y

 

   

      
   

         

 

    

    

    

   

   

  

 

          

        
         

 

       

   

      

 

_ . . . . ‘1‘ 11<._.I’I-.".. 1|
1 x? ...... . . . . .1 .o_ ....1..1o‘ v.h_.—.._o..¢. —o~1m¢_O-‘,—.o..l¢ ...-..qu 113'
. 1 . 1 . . . 1 . , . ......o. ... f.»-¢bp000.n.r61'ao.vv
. 1 .11.... ... _. _ _ . . . 1 . .. ......o..‘.111....11.1o I .. . r. . €1.1‘io ...-.11...
. . ._ n . . .11...1. .... 1 1.. .1 .. .1 1......0111... . .. ... I . 1 . . . . . .. .. 21...... .0I011 .....10...1.' R 1 o
‘ ... 1: ianM1‘J' 76.1.0. .‘o. ......o..\o..v “.... ...)..~{ '0 .. ......Droooc. .6. ...... . . a V ._ ¢ .q .1 .v‘ I .... ..1 1.1 1 . .. ... . .1. u 1 d... c . o. _’«l.‘vo d..b19al~o. .lb‘b”..b‘...‘..3|‘fo.:._
kg 1. .11.. J . . . ....1 ......1...;.. . . 1. . . . . . 1.‘1.p'.....tolc..o.1 . 9.1“
.. 1.1 ' .. . .1 ...s. . . . 1.1 o r. 1 y... o. . .o . . o .1 . ..I...1Av ... ::00.“'.LJ
’.‘.Q‘\.. . . ...1..... . 1.0a.1l..o.v..:.co..ooo_‘.1.
... .. .4. .....NQ....¢.$.. o. 1.1....r1. 11 1.11)» on 1 4ol‘...‘
.01 .... . .1. ... ...... ..M.u1_.n......10.1.1.... ooH.H....¢.u..ul ”41.81
. 1....1..... .1“ z... . .v . ... c .4.1...IJ.‘Q.I1.0 . a. t”. .\
7 1 n u a 1 o
1 1... . I . .1. o. .1 .....fv:o.l1m .....1 .1“. .3.
v.1 I. .11. .a" V. 1’ . I ....
. 1L a ...1. o .4 ...-o1 1.. .... h
.1 .1 .1»: _ 1.11..
. . I ...I.... . 1
.... , . .... . . .1
. 1.. 1 o. 1.. .. .
. . .. .... 1 ... g .
n. 1 .0: 1 .1 1 . . 1 .
"...... .. .. ..11 1. 1 . 1n... . 11 .. o o .. . . .1
. 1 11.... . . C 1 . .1 o . .. 1 . 1 .
I O 1 . ..a. o o a a 1. . o I 1. 1
.1 ....11 ...11 1.1.1:... ._. .... .. .o 1......1... .....1.‘ .... 1. .. a. . . .1 . :11. . . .1... 1.... 1 . ...: . .1
. 4.. 1 1.... 1. .9 9.1.5. . .l01o1.... . ... ......c...11..ou 1.1.... . . 0o 1 . .... 1 11 1.1.1 ‘ .1 . . . u. . . . . . u
.1 . l I . I.
L w

. 1,... . o 4 o. . . . 0......119 _
.o ‘6. O c . 11:1
.1...o. . .....1..Q. "0.0.1... . .

 

                      

 

     

. wwvv 1" ",‘F'
F?

1.:

.bum'ulb—uioht.

Kwhnflikr D. or

1r...ou1Lh.I11.o. 2.1.10.
8.....1‘0
'1... 3111. 1”]! .
. . . . . .1...J.u1_.11t..?....91.1..4s§.1fi.“.1..q.1.11....1
w . , ... 1 .. 1 . . 1 . , . . . ... .. . 1 . . . 1 .. . 1 ... W111w3M’ILC1O‘.‘161n§.m1 IY—C.1l
w I... .1 . .. . 1. 1 u . . . . .1 I _ - O 1. . 1 . 1 1 I.
w
v
w

11 gyro-H

o
I

. .v.’|’1’.o,c1..-I1f

. . . . .. .. _ _ 1:11 1.51%....”1111...

J:
1,9"
i
i
.‘i
1

   

 

             

. . 1.1.. .9»: .tglogon?‘1!..\o .1 1“
. . . . .. . . , .. . 1 1 .. 1. . .. .ngwia’u "“615‘131I1Opzr-» I
I 9‘ 1 .1...o.|o..u.-1V - . 1\.\.... . 1.. . ... 1 . .. . . . _ ,.

r. . .14...1l|1..1.o . .?4.. .11..
31.6.1114...b.1¢..1.1t:w1)”o1t. 11.1. I
. ... 'DI.‘ ..‘13... rt“..."

.. . . 1w]. vttonn’ouavua. .... 1.011.
. .. ..I. x I. 11.1... . 1. . 1 1..!1|.1. .11). .1. ’1...“
v ......10“...7._". .1. ..1MI.o.v row..1| 1.11.11.51.11”. ...".an ogé “fl.” .1 91.
... 1 1. .111...- t. . . i . ..
..II . . J1. . ".11“. 111....1...|l 9......311d1110: 3.0.1.1131. .1. .
4- L n

F"-

 

 

 

           

 

... 7.1.1 .
.1. 0. 2.11.1111. . .1
1..1_....v?.~1l‘.:| 3:11.

.71.".-

.ot...o 1v...11 .[910-

                           

 

 

. 1 .. ....1 ..£1’.111I.n1101.. .1".
.1 ....1'1.‘ ,1'l1u.ac ...?‘151‘0'1‘.’ ”o."
.v
A
a. . .

 

 

. ‘5‘... .
.. l 1. 11!. ...: .11. .?¢-I.' D..Fs|)'.y1p..11 09.51. Ouk.“§n1

31.11..» {.1921 1.. ..

 

'. .‘aqua a; 2:9de' '9

       
       

 

     

   

 

1.. 11‘.
, . 1 . . . r. .(l...)..l..|.!.
. 1. . . . . . ,.. . 1.1.1....
. . . .. . 1 1. . 1 1 1 1 . . . . . 1".
O 1 . . . H . . .. . 1 .. 1 . .. . . . . . . . . . . . Inluno‘... 1.1 11.. o r... .1»...L|¢1I.1. .1 '1 1121'
1 O 1 '0 I . . , 1 . . . . 1 a '1' ...... v. 1.1.1.! ”Jpn“. u ’D.. . ~VC" [1‘ .vfi‘..-‘. 11.
. . .. . 1 O 11-1,..1111‘V1x111.14.\11 11
a . 1 .. ”1.3.1-1.. 1.1.1.. .1
.C . 11 . . .1 .1KI.
P . 1 . . u. .
. _ a. ..
. V 1 ' O C . 11.
a. . . ,
. .
mm? . . .
... . ..
m _
.1 a
s 1
. . 1. 1 .1
.0 1
o
o
p 1
o
c
O
w
* a
O
O
O
O
C .
.1 . .
‘l o . o a
O o I I 11 1 '0’.
O1. . 1 . . . 1 11 . 1 1 1 v 1 I 1 .1111. 1
.Q 1 1 I . . . 1 \. 1 1. 1 1 1.. 1.1
1 1 1 1. . o 1 o . , v o 1 11
. 1 . . 1 1 a 1 1. 1 1 11 I. _ 1 1..-
o . . o 1 1 1 1 I II
01 1 . 1 . . 1 1 I. I 1 l .. 1 1 n
O 1 o 1 1 1 1 . 1 .1 . 1 11 0 1 11' I
u . 1 .. . - .. 1- 1
1 . .11 I I I v I 1 .1
v 0 1 . I . I o 1 I .
n 1 . ‘11 .I 1 1o 1 1
1 . . 1 I 1.!
. . . 1 1 . . .1
"O 1 1 1 1 1 1 1 LI 0. u
1 11 1 1 1 . 1 .
fl . O 1. 1 oI \ 1 1 11 1 .11 I I
. 1 1. . . . . . 1 . 1. 1. 1 .11 1 1 . I 11 1
0 . 1 _ . 1 I 1 o 1 . 1
II . 1 l 1. I 1 .I
1 I 1 ‘ . v 1 'l I I
u . 1 1 o . 1 I 1 1 . 1 ..I .
O 1 1 . 1 ’1 r
1.. . . - . - 1 - 1 -
I- ‘ I - |
. . 1.1 1 1 I '1
1 1 II 1 1|
” 1 0 V 1 I I1 . 1.1 1 '
O. . 1 1 1
C . 1 . I I 1 1 I
H _ . . . 1 I 1 1 I 1 II . 1
O . l 1 I I . 1 1 11
. . . . O .1 I. I1 I
. s . .
w . . .
01
O".

 

. .5 . 1. . .3... 1 1 1, . 1 .1 1...-.... u. 11 O . ......1? .... .....1......1.41..r. .1 .1411...|.1a~. ..1 ...4”.”wua..9.o.;1.mfi1lo11e.‘1a.1rnm.1“.rau.oni..~
. . .. . 1 ..1... . . ..1 . 1 .1 1 1 .1... . 11.1.1 . .. 11.11. 1. .1 1...!
‘. I 1 6.. I1 1 _ ... . .. ..1 lo. a .. .... . . a 1 1. . 1......1.... 5&6... ...-Jag
1 . 1. o 1 . . . . 1” 1. .1 . . 1.. \3 . . v u... _ . 1K1.£
.. . . ,. _ .. . b... ... ..., 1 .1 1.11... 1. fuzz. e. $4....r116tz3 ........._....“has...) .1 .........r8_11..n.....11. .1.......u1......._... .1193... ....r. 1. . :v......_:...1 1.11........r1.1u. ..A.¢..:~.....1w..«s.. 4. ....a.
. ‘u. . 1 C. 1 .I . . . 11L. . O. . 1. . . . I . _ . . 1

 

THESIS

FWJWJ‘

LIBRARY

1'. ' ,,
hacks-mu Sims
\_1

3,} U‘iix’czsxt3'

I
u
3
59‘4”" ‘~' " «P1 010* ; -~Q'-.

 

 

  
  
 

  

alumna av
“ale 5 SOIS' {;
L7 00K BINDEHY'

Ummv amoens

  
    

 

ABSTRACT

PHOSPHORUS RESOURCES, UTILIZATION, AND
RELATED ENERGY EXPENDITURES
By

Robert Kirk Johnson, Sr.

Phosphate rock is the raw material for numerous indus-
trial and agricultural applications. Reserves are being
depleted steadily by increasing demand from a growing
population. Reuse of phosphorus in wastewater could post-
pone depletion although related energy requirements are
significantly higher.

Part I includes a cursory review of the biological
significance of phosphorus and the geological characteristics
of mineral rock phosphate deposits. Current data on re-
serves, production, consumption and market characteristics
have been compiled for the world and the United States.
Projections of consumption through the year 2000 were made
and schedules of a range of depletion rates have been formu-
lated. Rhosphorus in wastewater has been identified by
source and potential quantities available for reuse calculated.

Part II outlines energy expenditures of two alternative
.methods of phosphorus application. Energy requirements for
fertilizer phosphates have been evaluated from the time of
extraction through refinement, transport and application
to the soil. Similarly, energy expenditures resulting from
the use of municipal sewageeffluent have been traced through

collection, distribution and application to crops.

Robert Kirk Johnson, Sr.

It is concluded that application of effluent for the
purpose of plant nutrition and prolonging resource life is
not economically feasible at this time, within the framework
of this analysis. The advent of alternative power sources,
possibly nuclear, could make reuse schemes more favorable.
Additionally, the relative importance given non-economic
considerations, as abatement of environmental degradation and
effective planning of resource exploitation, could influence

evaluation of proposed recycling.

PHOSPHORUS RESOURCES, UTILIZATION, AND

RELATED ENERGY EXPENDITURES

By

Robert Kirk Johnson, Sr.

A THESIS
Submitted to
Michigan State University

in partial fulfillment of the requirements
for the degree of

MASTER OF SCIENCE

Department of Resource Development

1974

TABLE OF CONTENTS

LIST OF FIGURES . . . . . . . . . . . . . . .

LIST OF TABLES . . . . . . . . . .

INTRODUCTION .

PART I.

l.

PHOSPHORUS RESOURCES
Biology and the phosphorus cycle

1.1 Biological significance . . . .
1.2 Phosphorus cycle . . . . . . . .

Geology of phosphate rock .

2.1 Apatite deposits of igneous
origin . . . . .

2. 2 Guano and related deposits

2. 3 Sedimentary phosphorite and
weathering derivatives

Phosphorus rock reserves .

3.1 World reserves . .
3. 2 United States reserves

Phosphate rock production and con—
sumption . . . . . . . . . . . . .

U.l World production and consumption
4.2 United States production .
“.3 United States consumption . .

Consumptive patterns and future demand
for phosphorus . . . . . . . . . .

5.1 World population trends and
agricultural production . . .
5. 2 World consumption and future
demand . . .
5.3 United States consumption and.
future demand . . . . . .

ii

Page-
iv

vi

CDO\U'1U'I

KOO)

10
l2
12
l”
20
20

25
29

37

37
A0

A8

Table of Contents (con't.)

PART

II.

1:.

Depletion of phosphate reserves
6.1 World reserves .

6. 2 United States reserves

6. 3 Contingencies

Phosphorus reuse

ENERGY EXPENDITURES

Introduction

Fertilizer manufacture .

2.1 Phosphate rock mining

2.2 Phosphoric acid manufacture

2.3 Triple superphosphate manu—
facture . .

2.” Transportation and application

2.5 Summary . . . . . . .

Wastewater reuse

Reuse systems
Conveyance systems
Land application
Collection systems .
3. 5 Summary

WWWUO
EWMI—J

Summary and conclusions .

LIST OF REFERENCES

iii

Page
5A
5A
58
66

75
79

79
86

88
9O
91

95
95
96

99
101

101
10“
108

Figure

10

ll

12

13

14

LIST OF FIGURES

The phosphorus cycle
Major U. S. phosphate rock reserves

World and U. S. phosphate rock produc-
tion 0 O O O O O O O O O O O O O O 0

World phosphate rock and fertilizer
production, consumption and trade,
197l o o o o c o o o o o o o o 0

United States phosphate rock produc-
tion . . . . . . . . . . . . .

Flow of phosphatic materials in the
U. S. phosphorus industry .

Distribution of phosphatic materials
in the United States . . . . . . .

World phosphate consumption, 1950-1970,
projected consumption to 2000 . . . .

United States phosphate consumption,
1950- -l970, projected consumption to
2000 . . . . . . . .

Projected rates of growth of world
phosphate consumption . . . . .

Schedule of depletion, world phosphate
rock reserves . . . . . . . . . . . .

Projected rates of growth of United
States phosphate consumption . . .

Schedule of depletion, United States
phosphate rock reserves . . . . . . .

Relative quantities of high, medium,
and low grade phosphate rock produced
in the United States . . . . . . .

iv

Page

15

22

23

26

28

31

AA

50

56

57

59

60

6A

List of Figures (con't.)

Figure

Page
15 Typical section of the Phosphoria
Formation in southeastern Idaho . . . 80
16 Section of inclined winze, Arickeree
Phosphate Mine, Rich County, Utah . . 83
17 Flow of wastewater in reuse systems 97

LIST OF TABLES

Table Page
1 World phosphate rock reserves and 1970
production . . . . . . . . . . . . l3
2 United States phosphate rock reserves
and 1970 production . . . . . . . . . l6
3 Phosphatic fertilizers . . . . . . . . 33

4 Per capita daily food supply, 1960 and
2000 . . . . . . . . . . . 38

5 World population and phosphate fertili-
zer consumption, 1970 and predictions
for the year 2000 . . . . . . . . . . 41

6 Distribution of phosphorus in regional
markets . . . . . . . . . . . . . . M7

7 Predicted United States demand for

phosphorus in the year 2000 . . . . . 52
8 Sources of phosphorus entering U. S.
surface waters . . . . . . . . 67
9 Average effluent characteristics of
various treatment facilities . . . . . 71
10 Energy requirements of phosphate rock
mining operations . . . . . . . . . . 82
11 Energy consumption per metric ton of
phosphoric acid produced . . . . . . . 89

12 Movement of raw and finished fertilizer
materials and related energy consump-
tion . . . . . . . . . . . . . . . . . 92

13 Energy consumed by triple superphos-
phate manufacture, transport and
application . . . . . . . . . . . . . 93

14 Examples of alternative effluent
conveyance systems and related
energy consumption . . . . . . . . . . 98

vi‘

List of Tables (con't.)

Table Page
15 Energy consumption of selected
irrigation equipment . . . . . . . . . 100
16 Components of a theoretical wastewater
project for Clinton, Iowa and related
energy consumption . . . . . . . . . . 103

vii

INTRODUCTION

Phosphorus is one of the most important elements be—
cause of its irreplaceable function in biological processes
and its relative scarcity in the biosphere. Phosphorus from
large localized deposits is extracted and utilized in a
myriad of industrial and agricultural processes. Man's
careless pattern of use disperses phosphorus in the form of
wastewater to surface waters, effectively rendering it to
unavailable storage. The source of commercial phosphorus,
phosphate rock, is diminishing at an undetermined rate. The
most liberal estimates of the life of this resource place
the date of depletion at several hundreds of years. This
time period represents a very small segment of the natural
cycle required for the formation of deposits the type of
which are now being exploited.

It has been suggested that the reuse of phosphorus in
waste could postpone depletion of reserves hundreds of years.
One of the more popular schemes for reuse of the element
includes the application of sewage treatment plant effluent
to agricultural land by a variety of methods. A potentially
significant obstruction to land application techniques is the
amount of energy required for transmission of the liquid waste
to the agricultural site from the treatment facility. The
current status of fossil fuels in the United States and the

1

2
world and consequent higher energy costs will make power
requirements an increasingly larger percentage of operational
budgets.

In consideration of increased concern for the longevity
of this essential, finite mineral resource, combined with
inadequate knowledge of energy expenditures associated with
alternative management schemes, the following hypothesis
is advanced. Energy inputs required by reuse projects apply—
ing a unit of phosphorus contained in wastewater will be
significantly higher than those requirements related to the
application of an equivalent amount of phosphorus from
manufactured fertilizers.

The approached to be taken in addressing this hypothesis
is a theoretical comparison made to determine the relative
energy requirements of the two basic alternatives for appli—
cation of phosphorus. The first alternative to be evaluated
will be the application of manufactured fertilizer, triple
superphosphate, derived from mineral rock, proceeded by a
second method applying effluent from sewage treatment facil-
ities. A centrally-located farm in midwestern United States
will be used as the recipient of phosphorus. Discussion will
include methods of fertilizer manufacture, modes of trans—
portation and systems of wastewater utilization. Energy
expenditures will be compiled for operational activities,

excluding requirements of capital equipment and installation.

Methodology
Biological significance and cycling of phosphorus in

the natural environment will be evaluated. The location,

3
quality and volume of world and United States reserves of
rock phosphate will be compiled in detail from an extensive
review of the literature. Phosphorus production and patterns
of consumption shall be presented and projections to the year
2000 made. Schedules of reserve depletion will be formulated
for the world and the United States.

Energy requirements will be evaluated for alternative
methods of phosphorus application. Fertilizer manufacture
and use will be traced from representative mines in the
western fields and Florida through respective refining pro-
cesses, modes of transportation and application by farm
machinery. Conveyance of effluent from a treatment facility
to regional delivery points, distribution to the farm and
application by alternate techniques will be described. Data
for total energy expenditures shall be compiled at the con-

clusion of respective sections.

PART I. PHOSPHORUS RESOURCES

l. BIOLOGY AND THE PHOSPHORUS CYCLE
1.1 Biological significance

Phosphorus is a universal constituent of protoplasm
required for growth and reproduction in all forms of plants
and animals. Phosphorus shares its importance with other
elements (nitrogen, oxygen, hydrogen, carbon and sulfur) but
differs in availability. Other elements of major biological
significance are readily obtained where phosphorus is bound
in mineral rock.

Phosphorus does not occur in elemental form. All phos-
phorus is in the form of soluble and insoluble phosphates
which are found in the soil, freshwater and in the seas.
Soluble orthophosphates are present in relatively small
amounts, the concentration effectively controlled by solubili-
zation processes and cations as calcium, iron and aluminum
which are capable of forming highly insoluble orthophosphates.
In plants and animals phosphorus occurs as orthophosphates,
polyphosphates, ortho- and polyphosphate esters, phospho-
proteins and complex nucleotides.(l)

Insoluble mineral phosphates constitute the majority
of fixed phosphates in the soil and mineable rock deposits.
These compounds can be biologically utilized over a number
of years in many soil environs through activity of micro-
organisms, leaching by carbonate waters and other means.

Although the earth's supply of phosphorus remains constant,
5

6
the amount biologically available varys, at a rate which

is a function of its turnover.

1.2 Phosphorus cycle
The phosphorus cycle is illustrated in Figure l, which

includes major natural and cultural pathways. The cyclical
processes provide the basis for phosphorus concentration,
biological utilization and eventual return to the sea.

A portion of the earth's phosphorus is continually passing
out of the mineral reserve into living substance and sub-
sequently re-entering from living matter back to the mineral
reserve. Solubilization and growth proceeded by deposition
and decomposition provides the mechanism which assures an
almost universal distribution of biologically available
phosphorus over the surface of the earth.

The natural cycle of phosphorus occurs over extremely
long periods 0f time,requiring millions of years for
geologic uplift of depositions to complete the cycle. The
portion of the sequence influenced by man, however, has
effectively created a subcycle with a flow of phosphorus
to non-available storage greater than the flow from non-

(3)

available storage.

. ><3Ih<a 4(1thqu
A HHHcccscm Lcccmv
6.3ch maccccmcnc c5. A $sz 53:5; 455:: .||.I.|

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

\ all. III II mw¥<4 /
\ /
\ X /

\ \
.R x a
w o ... Vs .

u
r mzfiggtuulw. 0:33 .
. ~ _
+ \
3.330 \ _
2:3: _
. I _
u > a «E ... X _
20::qu + \ I. 3.3... ’ \
823m £3: a. / k \ \ c285 .
\ 032.000 2:30 ...—Ow A! I actozhuoz
amazom _ \ v // _
3:0980o \
co <
2cc§§ TIA "13.4.29. VAV inhoswcomk \
0. can. .
39.0 Au! // , v.00: \ _
l I Efizmsamw \
I

I l 50: 3820. \\

 

2. GEOLOGY OF PHOSPHATE ROCK

Phosphate rock is generally considered to be any rock
that contains one or more phosphatic minerals of sufficient
purity and quantity to permit its commercial use as a source

(4)

of phosphatic compounds or elemental phosphorus. There are

three general types of phosphate deposits, classified accord-
ing to the process responsible for their primary localization:(5)
l. Apatite deposits of igneous origin

2. Guano and related deposits

3. Sedimentary phosphorites

2.1 Apatite deposits of igneous origin

Apatite deposits occur primarily as intrusive masses
or sheets commonly associated with alkalic igneous rock
complexes. Deep weathering may yield a phosphate—rich
residuum at the surface during decomposition of calcite,
dolomite, and other more soluble minerals. Some of the
largest igneous deposits are found in the Kola Peninsula
of the Soviet Union, in Eastern Uganda and in the Republic
of South Africa. Their content may reach 36% P205 with
average grades between 20 and 25% P205.(6)

The remainder of igneous apatite deposits are either
less extensive or lower quality and consequently are of less
economic importance. Low yield deposits are found in Vir-

ginia, Norway, and southern Ontario.

8

9
2.2 Guano and related deposits
Large accumulations of guano are formed primarily by
seafowl with smaller quantitites deposited by bats and other
cave-dwelling mammals and birds. Bat guano is most abundant
in cave districts of temperate and tropical regions, however,
accumulations are small with mining seldom greater than a

(7)

few thousand tons. Seafowl deposits are mainly confined
to islands and coastal regions in low latitudes, the largest
of which lie along the west coasts of lower California,
South America, Africa, and islands near the equatorial currents.
Many guano deposits were once several hundred thousand metric
tons although most of the fossil accumulations are now de-
pleted. Current production is very low, less than 0.01% of
world phosphate rock production.(8)
Fresh seafowl droppings contain about 22% nitrogen and

4% P Decomposition proceeds rapidly and the relative

205'
phosphate content increases as the nitrogen and organic matter
decreases. Modern guano contains about 10% P205 whereas
leached guano contains 20-32% P205. In areas of rainfall the
soluble phosphates are carried to underlying rocks where they
may be deposited as cavity fillings or replacement. Through
this process, phosphates from guano have accumulated over long
periods of geologic time and formed significant deposits as
those found on the island of Nauru in Oceania where original
reserves of rock are estimated to have been 30 million metric

tons of rock averaging about 39% F205 (3)

10

The mineralogy of phosphatized rock derived from guano
depends on the composition of the host rock. Limestone as
found in coral reefs results in apatite while silicate of

volcanic origin yields aluminum or iron phosphates.

2.3 Sedimentary phosphorite and weathering derivatives

Most of the world's phosphate production comes from
marine phosphorites. The richest and largest of these form
at low latitudes in areas of ocean upwelling, chiefly along
the west coast of continents or in large Mediteranian seas
along the equatorial side of the basin. Lesser but signif-
icant concentrations form along the west sides of poleward-
moving warm currents on the eastern coasts of continents.

Rock assemblage in the cold—current environment is the
product of deposition on a shoaling bottom, over which
shoreward moving waters are progressively warmed. The
thickest accumulations of phosphorite form in areas of geo-
synclinal subsidence generally associated with carbonaceous
shale. The phosphorite is typically carbonaceous and pelletal
but nodules as well as skeletal material may be present in
lesser quantities.

Individual beds are generally a few meters thick and
often many kilometers wide containing up to 30% P205. Thicker
and richer deposits may occur locally but are highly lenti-
cular. Phosphorites deposited from upwelling are found in the
Phosphoria Formation in Idaho and adjacent states, extensive
deposits in western and northern Africa, and in the Middle-

East.

11

Phosphate deposits formed in warm-current environments
along the eastern coasts of continents generally consist of
phosphatic limestone or sandstone and are less extensive and
lower in quality than those formed from cold currents.
Depositions derived from warm—current activity are found in
the Bone Valley Formation of central Florida. The distribu—
tion of some deposits suggests estuarine deposition and may
have resulted from processes of circulation and nutrient
enrichment.(9)

Secondary processes have played a prominent role in con—
centrating the richest of the marine deposits. The highest
grade beds in the Western Phosphoria Formation appear to have
been extensively washed by marine currents and leached of
carbonates and sulfides. Weathering in the cycle accounts for
the formation of enriched residual and replacement deposits
from phosphatic deposits not otherwise mineable. Tennessee
"brown-rock" consists of present day residuum developed

through decomposition of phosphatic limestone.(lo)

3. PHOSPHATE ROCK RESERVES

3.1 World reserves

Phosphate rock occurs throughout the world and is mined
extensively on every continent although three regions -
the United States, the Soviet Union and North Africa —
constitute over eight-tenths of the world's developed
resources. These deposits have provided a dependable source
of phosphate rock in past decades and will continue to supply
foreseeable demand for the next few hundred years.

Table 1 contains a compilation of the world's known
and potential deposits of phosphate rock, equivalent quan-
tities of P205 and 1970 regional production statistics. The
North African region possesses the largest reserves while
North America produces the largest volume of rock. European
reserves are almost exclusively found in Northeastern Russia.
Total known and potential reserves of the world are nearly
160 billion metric tons of rock or about 43 billion metric
tons P205 equivalent at an average assay of 26.9% P205.

Many deposits contain relatively insignificant amounts

of phosphate rock. Recent discovery and exploitation of
reserves, particularly in underdeveloped nations,

has decreased dependency of smaller countries on major
producers for raw phosphate materials. The three major
producing regions have supplied the rest of the world

with rock and phosphorus derivatives, specifically resource

12

313

TABLE 1

WORLD PHOSPHATE ROCK RESERVES AND 1970 PRODUCTION
(million metric tons)

 

 

 

 

 

 

 

 

 

RESERVES PRODUCTION
(ref. 8)
Avg. Percent of Percent
Location Ref. Rock P205 Grade Total P205 Rock of Total
WORLD 159,303 42,974 27.0 100.0 85.32 100.0
AFRICA 71,426 22,555 31.6 52.5 19.84 23.2
Algeria ' 6 2,791 831 30.0
Angola ' 11:14 111 39 35.0
Egypt, Arab Rep. 8, 11:11 745 223 30.0
Mauritania 11:4 4 1 25.0
Morocco 6 59,590 19,138 32.1
Rhodesia 12 34 3 8.1
Senegal 11:13 -' 45 14 30.0
South Africa,
Rep. 11:12 363 22 6.0
Spanish Sahara 11:4 1,179 360 30.5
Tanganyika 12 9 2 20.0
Togo, Rep. 11:2 45 16 36.6
Tunisia 6 6,281 1,869 29.8
Uganda 11:7, 12 229 37 16.3
ASIA 8,134 2,027 24.9 4.7 5.76 6.8
China, P. Rep. 6 7,419 1,868 25.2
Christmas Island 1 :4 181 40 22.C
India 8, 11:9 144 42 29.2
Israel 11:8 7 2 27.0
Japan 2 24 8 35.0
Jordan 2 5 1 27.0
Lebanon 11:1 5 1 25.0
Syrian Arab Rep. 11:3 168 45 27.0.
Turkey 8 181 20 11.0
OCEANIA 2,127 408 19.2 0.9 2.63 3.1
Australia 8 1,887 323 17.1
Makatea Island 2 8 3 35.0+
Ocean & Nauru
Island 2 232' 82 35.0+
EUROPE 26,570 5,487 20.7 - 12.8 20.92 24.5
France & Poland 2 358 90 25.0
U.S.S.R. ' 6 26,212 5,397 20.6
NORTH AMERICA ’ 49,499 12,033 24.3 28.0 35.29 41.4
Mexico 11 10 140 22 15.6 '
United States 6 49,359 12,011 24.3
SOUTH AMERICA 1,547 464 30.0 1.1 0.88 1.0
Brazil 11:6 120 22 18.3
Columbia 11:8' 5 1 20.0

Peru 11:3 1,422 441 31.0

 

l4
deficient Europe and Japan which employ intensive agricul-

tural practices.

3.2 United States reserves

Twenty-three states in the United States have reported
phosphate rock deposits. Significant deposits are found in
Florida, North Carolina, Tennessee, and the western mountain
states (Idaho, Montana, Utah and Wyoming). The geographic
locations of important commercial reserves are summarized
in Figure 2. Current data on U. S. known and potential
reserves and recent U. S. production statistics have been

gathered in Table 2.

Florida reserves<lu>

 

Florida's major deposits of phosphate rock are modular
or pelletal conformations found in the Bone Valley Formation,
located in the west-central portion of the state. The forma-
tion covers an area of about 6,700 square kilometers with the
highest grade rock situated in the northern sector. A
typical bed consists of a 6 meter thick overburden of quartz
sand under which is a 2 meter leached zone containing 20-30%
calcium-aluminum phosphate minerals. A 5 meter thick bed
of matrix follows comprised of an unconsolidated mixture of
one-third phosphate pellets, one—third sand and one-third
clay and sand slimes. The pellets range in size from minute
to 2.5 cm in diameter.

The deposits are fairly continuous in both grade and
thickness over large areas although abrupt variations may

occur locally. Overburden ranging from 3 to 6 meters must

15

          

 

 

hoummv

 

 

.AzaoHoHEmcoz one oa.coooaoaz
pom Sufism ma.%c>ao&o2
.mo>momoh x009

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

epwndmoco .m .3 sends .m onswfim
cozmpto.
>622,
ocom
x09 Em: .... ._ .15”:
, . _ \ 532523
_ . .. \ 02.8....
sec. . .. 62.20; \\
\\\
. 02.5.
9.6.8 .
some new 2200 ..

 

 

.2520:

l6

oofieoam ca ooosaoca

on

 

 

mmuMum cumpmcz :H oopsaoca Any
commences ca Umvsfloca Adv
o.ooa :m.oa ma.mm o.ooa m.:m mHo.mH mmm.ms 0.0m omH.m Hofi.e a<eoe .m .a
m.mm H.Hm omo.: oem.~s m.m: mmm mam mcfieoszucooa
m.m m.:m mam oem.a m.mm mmm mmm ccoocoz
m.mH m.mm smm.a Neo.o m.=m Hom mHN.H oaooH
H.0H oa.a mo.z “mmpwpm cpopme3
H.A ms.o mm.m m.m o.Hm m=H.A m:=.m m.e~ HH mm mommoccoe
on on. on III: on a: a: m.mm mow mmo.m «GHHOAwo nanoz
III III III III: as m: me III III II: mfiwpooo
m.mm mo.o =m.mm m.Hz H.Hm mmm.= mmm.mm H.mm 3mm Heo.m oofitoam,
ADV Any any III: a: m: m: we as m: macnouaamo
III nII III IIII m.mm m ma III III II: momcmxh<
Adv Amy Amy III: «C we as III III III msmnma<
mono momm xoom moma cocoa meme xoom oooto memo Room
HMWMWAWM Hmmwwcwm S<Hezmeom zzoze
Am .menv Am .mehv
oneosoomm mm>mmmmm

 

ZOHBODQOmm ouma Qz< mm>mmmmm xoom ma<mmmomm mME<Bm QMBHZD

Anson owpums cowaawsv

m mqm<e

17

be removed in order to mine the matrix which is usually
3 to 10 meters thick. Areas presently mined are about 35
meters above sea level in flat terrain.

Florida's hard-rock deposits are located in the north-
central area of the state. The rock is in a belt about 30
kilometers wide and 200 kilometers long aligned on an approxi-
mate north-south axis. The beds vary greatly in thickness,
ranging from about one meter to over 30 meters in depth.

The hard-rock is covered by an overburden of clay and sand
which has been economically stripped to depths of greater than
20 meters. Mining in the area has been undertaken by as

many as 70 operations although present production is limited.

(10)

Tennessee reserves

 

Three types of phosphate rock are found in Tennessee
formations - blue, white and brown rock. Blue rock consists
of phosphate pellets cemented with calcium carbonate and
white rock occurs as a heavy, massive material with a knurly
structure, commonly found in thin beds. Neither of these
have been extracted at significant levels in recent years.

Brown rock is composed of residual francolite pellets,
quartz sand, and clay derived from the decomposition of lime-
stone depositions of about 350 million years ago. The phos-
phate was originally deposited in shallow seas, later to be
lifted gently and exposed by erosion. The brown rock often
occurs as fillers lying between layers of limestone. This
material covers a large irregular area traversing the center

of the state in a north-south direction. The overburden in

18
the brown rock fields runs from 0 to 15 meters thick,

averaging about 2 meters, while the matrix ranges from 1.5
to 3.0 meters thick averaging about 2 meters.

Tennessee phosphate rock reserves are of relatively
insignificant national importance. Commercial deposits are
expected to be depleted in 10 to 20 years, although low grade
deposits not currently considered as a reserve are available

(6)

in the region.

(15)

Western states' reserves

 

The Rocky Mountain phosphate rock field is referred to
as the Phosphoria Formation and covers an area of greater than
160,000 square kilometers in portions of Idaho, Montana,
Wyoming and Utah. This field is one of the largest in the
world and constitutes nearly 50% of U. S. reserves and greater
than 10% of world reserves. The remote location and consequent
high transportation costs prevented significant exploitation
until the early 1950's.

Important reserves are the result of depositions of
phosphatic material about 100 million years ago. From the
time of its formation the strata has been greatly compressed,
folded and uplifted resulting in beds that often dip at high
angles, frequently greater than 45 degrees.

Rock of the Phosphoria Formation often occurs in the form‘
of soft, weathered shales having a dark, somewhat oily appearance
and a high carbon content. The highest grade rock (30-45%
P205) is dense and usually appears partly modular, cemented

together with finegrained carbonates.

. 19
The thickest beds of high assay rock lie in an area

extending from the southeast corner of Idaho across the south-
west tip of Wyoming. Most high grade deposits can be
mined only by underground methods, however, there are a
few rich outcroppings which are worked by surface mining
in southeast Idaho and western Wyoming.

There are at present 33 phosphate rock mines in the
United States operated by 28 mining concerns. The majority
of the mines, 14, are in Florida while Tennessee and the
western states have operations at 8 and 11 sites, respec-

tively.(l6)

4. PHOSPHATE ROCK PRODUCTION AND CONSUMPTION
4.1 World production and consumption

Phosphate rock is the primary raw material of the
world's phosphorus and phosphate derivative industry,
representing 94-96% of total phosphate production. Basic
slag (a steel-making by-product from phosphoric iron ore)
forms a secondary source contributing 4-6% of production.
European usage of slag is higher than that of the world,
constituting about 25% of phosphatic raw material for that
region.(l7) Worldwide distribution of phosphate rock by
final use places fertilizer manufacturing as the greatest
consumer at 85% of total production. The detergent and animal
foodstuffs industries account for 8-9% and 6-7% of the total,
respectively.

World phosphate rock production was relatively static
from the establishment of the industry ca. 1910 until the
late 1940's. In the 20 year period between 1950 and 1970,
annual production increased more than 60 million metric tons,

from 24 to 88 million metric tons.(8)

The expansion of
production has supplied the world with raw material for
escalating fertilizer demand as well as a myriad of new
uses. Prominent among these is sodium tripolyphosphate
(STPP) used for detergent building. From the time of its
inception as a laboratory curiosity in the late 1940's, STPP

grew rapidly in a few years to the major industrial consumer
20

21
of phosphorus and continues to consume 5—10% of total P20
(18)

5
production.

Production of phosphate rock continues to increase
although rates are substantially lower than those experienced
in the early 1960's (Figure 3). Foreign exchange shortages,
world political unrest, less-than-anticipated purchases by
international agencies and inclement weather reducing agri-
cultural production in some areas has restricted consumption
and created a surplus of production capacity. In 1969-1970,
the world installed capacity of phosphate rock production
was approxiately 90 million metric tons annually. However,
the industry utilized only about 75% of capacity and a
surplus of about 18 million metric tons was realized by the
industry worldwide.(l7)

The distribution of rock phosphate and phosphatic fertili-
zer production, consumption, and international movement is
represented in Figure 4. Three major producing areas shown -
North and Central America, North Africa, and the Soviet Union -
constitute nearly 90% of the world's rock phosphate production.
Exportation of rock is undertaken by less developed countries
while more technically advanced nations export moderate
amounts of intermediary and finished phosphorus products
(primarily acid phosphates) as well as rock.

' Many regions of the world employing intensive, techno-
logically advanced agricultural practices are also deficient
in rock phosphate reserves, specifically Western and Eastern
Europe and Japan, all of which are heavy importers of rock.

Exports and imports are roughly aligned according to

22

 

1001
nWofld

80-
3.1
O
O
(I:
Cf)
g 60-
[—4
O
H
m \
E
23 40?

-v"
CZ) I- \"-- ”as.
H I
s x
E . 2’
4. 20" "o. ’
s o”‘-
"~"I 5"-
0 .

 

1950 1955 1960 1955 1970 1975

Figure 3. World and U. S. phosphate rock production.
' (from Harrel6)

23

ROCK PRODUCTION (ref. 8) WORLD 85.4

USSR 20.8 N. 8 C. America 35.3 Africa 19.9
1 N. S.
1 l »

,//" 7 A Oceania 2.6
.R.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Eu 0.1 I O
rope S America 0 9 China 1.2
Asia 4.6
ROCK EXPORTS, (ref. 17) WORLD 32.8
I
USSR 5.4 N. & C. America Africa 15.2 E
7.5 N. ° S.
, 1 1 l
I
Asia 1.4 Oceania 3.3
ROCK IMPORTS (ref. 17) WORLD 32.8
Europe 23.1 5 Asia 5.4 ,
wast : East I Japan Rest 1
l
C. America 1.4 Oceania 2.9
‘FERTILIZER PRODUCTION - P205 (ref. 19) , WORLD 19.4
‘ , -
Europe 7.7 E USSR N. 5 C. America
West i East 2.1 5.6 1 L 1
S. America 0.2] . ioéggnia 1.2
Asia 1.
Africa 0.7
P.R. China 0.5
_FERTILIZER CONSUMPTION - P205 (ref. 19) WORLD 18.8
If ,7 , ,
Europe 7.4 E USSR N. & C. America ASIA
west : East 1.9 4.8 II J.REST l I
I , , I
S. America 0.5 // I

P.R. China 0.5 Oceania 1.2‘
Africa 0.5

Figure 4. World phosphate rock and fertilizer
production, consumption and trade,
1971. (million metric tons)

24

conventional free world-Communist bloc delineations; the
United States exports to non—Communist nations; nearly 75%
of exports from the Soviet Union are destined for Eastern
Europe; North Africa exports to all major importers.(l7)
Despite its essential nature, phosphate rock is a low—priced
commodity and competition in world and domestic markets is
strong in spite of rising costs experienced by the entire
industry.(6)
Refinement of rock phosphate and phosphatic fertilizer
production is extensively undertaken in North America and
Europe where consumption nearly mirrors production. Countries
employing less advanced agricultural techniques use corres-
ponding lower amounts of manufactured phosphate fertilizers.
The People's Republic of China has only recently begun to
utilize small amounts of refined phosphorus in place of
natural manures. While feeding one-quarter of the earth's
population, China produces a little more than 2% of the world's
phosphate rock (while possessing sizeable reserves), imports
about 3% of the world's exports of rock, and produces and
consumes about the same quantity of phosphatic fertilizers.
As the earth's population continues to grow and the agricul-
tural practices employed by countries like China and India
become more sophisticated, world demand for raw fertilizer
materials will increase sharply. If global predictions of
population and income growth materialize, fertilizer produc—
tion over the next 30 years must triple to satisfy food

demands.(20)

25
4.2 United States production

Production of phosphate rock in the United States
originated in South Carolina and Florida. Florida continues
to produce the bulk of U. S. phosphates, as illustrated in
Figure 5. Reserves are sizeable after many years of inten-
sive production although not as large as those found in the
Western States. Florida's proximity to low cost ocean ship-
ping combined with the geologic nature of phosphate reserves
permitting strip mining has enabled extensive development
of that state's resources.

The Phosphoria Formation of the western states had not
been exploited to any significant degree until the early
1950's. Located approximately 1,050 kilometers from the
Pacific Ocean in mountainous terrain, movement of western
phosphates has been restrained by high transportation costs.
Western reserves are unlike those found in Florida and Tennes-
see in that less than 50% of obtainable rock may be surface
mined, the balance of which must be mined underground further
constraining development.(21)

The flow of phosphate materials from the mineral re—
source to major agricultural and industrial applications is
illustrated in Figure 6. Phosphorus in mineral form is
first concentrated and/or separated into several grades
for marketing and distribution within the industry. Most
rock does not result in an end product directly but passes
through a variety of other forms first. Low grade rock,

less than 30% P is predominently processed by thermal

205’
methods to elemental phosphorus. Rock containing greater

26

 

 

 

40-
5' ”(us
6 -'
g 30‘ f. .h ,I'FLA.
Cl] .° I
E"? .' I
B i
O 20- '
E /
E /
E ’1'
z , 3 .’”fl
0 uu' /\ «f’
:3 101 ,»-’r\/' V’
A ~~
H
2 ”\ ”\
,«V--. ’ ‘ ‘---WEST
W ATENN.
O r . 1 . . 4
19 1955 1950 1955 1970 1975

Figure 5. United States phosphate rock production.
(from Harrel6)

27

Figure 6. Flow of phosphatic materials in
the U. S. phosphorus industry.
(after Logue18)

 

28

 

 

 

.33: man—Z.
.meSwumbwhm ,
mahocmmoan
Uwcmmuo
mummmmocm
umwomuhs
poem .

 

 

 

 

 

.uwmm:u\~mwuum:@CK
.90... o «sesame:—

 

a

 

rmsmozmmozm negated

 

1.

 

 

quUQma QQEMWEB

 

 

, a

 

_~momm so

mv»
mhmub 30m

 

 

“mum Hoe. -
mmm cauocmmoamuemsm

 

.3055. #5306.

LEMNHQHkmmm
NMHQEOU

 

 

  

UZHQZNQN

 

— 202.03% <—

 

HummHQ

 

 

 

 

 

 

oumammocm, - oumcmmonm
Eswcoesm summsm Esflcoes.
Imwom mmumuucoozou sozoelws

 

 

 

mmumcumonm-
nouuwz

 

 

 

 

 

» l

Suwanee herwwuumm
IQHU< UHmdmmmomm

 

 

 

 

 

 

 

 

MUQEEQ QHUE

 

 

 

 

16.8.... No.85:

 

 

 

mmmooms REE

 

 

 

 

 

«meme .87; _
6636 :6.me -

 

 

H.

l a

Fiance me Seances w

“me 118348-852.er _

 

 

29
than 30% P205 is refined by the "wet-process"; aciduation

with a strong mineral acid, usually sulfuric acid. Most
industrial applications utilize phosphoric acid obtained
from the thermal process while fertilizer is derived chiefly

from wet-process acid.

4.3 United States consumption

Consumption of phosphorus in the United States is
dominated by agricultural usage. More than three-quarters
of all phosphates refined are channeled into fertilizer
production with the balance in a variety of industrial
products, shown in Figure 7.

The largest industrial use of phosphorus is detergent
building. About 7% of total rock production goes into the
formulation of commercial household detergents and cleaning
compounds. Most of the phosphorus is in the form of indus-
trial grade phosphoric acid derived from thermal process
elemental phosphorus with a small percentage from wet—process
acid. The major detergent builder is sodium tripolyphosphate
with lesser amounts of tetrasodium tripolyphosphate.

About 3% of consumption is used in plating, polishing
and other surface treatments of metals. Phosphoric acid is
used in baths for polishing and brightening aluminum, copper
and their alloys. A phosphatizing process is employed
which forms a protective layer of phosphate salts on metal
surfaces.

Another 3% of consumption is used in animal and fowl
feed supplements. Animal malnutrition has been associated

with phosphorus-deficient diets because of low nutrient

 

30

in the United States. (from Harre1

Figure 7. Distribution of phosphatic materialg
and U.S.D.I., Minerals Yearbook, 19718).

31

PHOSPHATE DISTRIBUTION

FortIIIzer 76%

 

 

FERTILIZER DISTRIBUTION

 
  
  

Concentrated
Simple Super-
phosphate

SuperphOSphato 31.0 %

Ammonlum 0.0. . .. . . .
Phosphate 9.3% ,' ' 0 0 o

 
      
 
 
     
    

53;; ' Other 8.1 x

Dlammonlum
Phosphate 36.7 X

32

levels in natural feed supplies. These supplements must
possess very low fluorine levels which are derived from
dicalcium phosphate prepared from thermal process phosphoric
acid. The fluorine present in U. S. domestic rock prohibits
its use for animal consumption. The resulting demand for
defluorinated rock represents the only imports of phosphatic
material into the United States.

The "other" or undistributed category includes a
multitude of end products, all requiring small amounts of
phosphorus. Among these are intermediary or finished
phosphates for soft drinks, matches, water softening materials,
insecticides, dentifrices, rat poison, and many others.

Three-quarters of all rock phosphate produced in the
United States is consumed in the manufacture of fertilizer.
Fertilizer production primarily involves conversion of rock
to more soluble phosphorus compounds which may be effectively
utilized by plants. The chemical process of solubilization
of phosphate rock with acids is basic to the industry.
Continued technological improvements have resulted in more
economical production of higher analysis, better quality
products.

Phosphoric acid (H3POQ) is the basis of phosphatic
fertilizer production. It is the initial ingredient for super—
phosphates and ammonium phosphates and functions as an I
intermediate for liquid and solid mixed fertilizers. Table
3 contains an analysis of phosphoric acids and fertilizers

which employ them as a primary input.

33

Amm .momv .cmmHQOHS mom

mCOHpmocoEEooom LONHHHpnom .mmma aHHOQ .0 .m one mmosq .m .m ..m .9 «concoumhflco ”condom

 

 

ma om m: N: zommmAzmzv cpwnomonm EsficoEEmHQ
Ha mm m: m: zommmqmz mpmzdwogo SoficoEE<
0 mm mm mm mflsomvzmeo .nooon escape
0 mm m: m: mAzomvzmmo .AOQSm woumppcoocoo
0 mm om Hm mfizomvnmmo concomOSQLOQSm HmEsoz
o ooa we we NOmmzm mzommm Uflom camocomocohomsm
o ooa :m :m 20mm: Uflom cahonmmonm
o o mum em maoo.mAeomvmoom oooeonoeo Room
OHQSHom oaomHHm>< Hence mHsEpom Show
Lepmz &
zmoomBHz m m
BZMommm u o m Bzmommm

 

mmmNHAHBmmm me<mmmomm

m mdm¢9

34

Conversion of rock into fertilizer material begins
with a complex beneficiation process that involves wet
screening, hydroseparation and concentration by flotation.
Following beneficiation, the rock is converted to phosphoric
acid by the "wet-process" or the thermal process.(23)'
Wet—process acid is produced by the action of sulfuric acid
on ground beneficiated rock. The acid is then separated
and concentrated. The thermal process reduces rock phosphate
with coke in an electric-arc furnace resulting in a more
pure acid but at considerably higher cost. Because of this

cost factor, the ratio of wet-process acid to thermal

process acid used in fertilizers is about four to one.

Superphosphate is a derivative of phosphoric acid which
was first processed in England in the 1840's. The procedure

consists of reacting sulfuric acid with phosphate
rock to obtain phosphoric acid followed by aging or curing
the mixture. The result is a dry porous material, "normal"

r."(2u) From its

superphosphate, CaHu(POu)2 or simply "supe
inception up to the 1950's, superphosphate was the major
source of fertilizer phosphorus throughout the world. It
proved to be an efficient, easily manufactured material
with few problems associated with storage and application.
Superphosphates have been consistantly regarded as the best
of available phosphorus carriers over a wide range of soils,
climatic conditions, and crop management practices.
Concentrated superphosphate is manufactured utilizing

the same techniques employed to obtain superphosphate.

However, orthophosphoric acid is used to aciduate phosphate

35
rock in the place of sulfuric acid. The resulting compound

contains more than double the available P205.(25) Concen-
trated superphosphate has figured predominately in fertilizer
manufacture since ca. 1950 and reached the level of produc-
tion nearly double that of Simple superphosphate shown in
Figure 7. The specific advantage realized with the use of
concentrated superphosphate is the increased P205 content and
subsequent reduction in transportation, handling, bagging,
storage, etc.

Concentrated superphosphate can be further refined to
produce triple superphosphate yielding 55-56% P205, presently
a low volume fertilizer material. The same aciduation process
is employed although triple superphosphoric acid (76-85%

P205) is used.(26)

Additional savings in transportation and
handling may be realized.

Phosphate materials are combined with nitrogen to form
a variety of mixed fertilizers. Forms receiving the greatest
usage are ammonium phosphates, which include a sizeable
number of fertilizers produced by ammoniation of phosphoric
acid.(27) Ammonium phosphates may be formulated as a mono-
ammonium or diammonium salt or mixtures of the two. They
may be used for direct soil application or as an intermediate
in mixed and blended fertilizers.

The chemical and fertilizer industries undertake con-
tinual research in development of new techniques and pro-
cesses for phosphorus refinement and application. Many new

fertilizer products experience low initial usage and are

included in the "other" classification of Figure 7. A

few recently developed fertilizers are as follows:

36
(28)

ammonium polyphosphate (15-60—0): produced from
superphosphoric acid

powdered monoammonium phosphates (ll-48-O):
produced from superphosphoric acid; one of the least
expensive forms to transport

ammonium phosphate—urea (18-45-0): produced from urea
and concentrated phosphoric acid

metal ammonium phosphate (8—40—0—14 mg): effective
fertilizers with slow-release nitrogen; expensive

potassium phosphates (0-56-36): high concentration
of nutrients but difficult in manufacturing

5. CONSUMPTIVE PATTERNS AND FUTURE DEMAND FOR PHOSPHORUS
5.1 World population trends and agricultural productiOn

The population of the earth in 1970 was slightly greater
than 3.6 billion people, reflecting a worldwide annual in-
crease of about 2% over past decades. The rate of growth is
expected to slow to about 1.7% at the end of the century and
the year 2000 is predicted to see nearly 6.5 billion inhab-

(29)

itants. Less developed regions (much of Asia and Africa,
Central and South America, and parts of Oceania) are more
heavily populated than developed regions by a ratio of about
2.3 to l. Accelerated growth is experienced by less developed
areas which exhibit rates well above the world mean. Most

of Asia is expected to increase at a rate of 2.5% or greater
while Africa may exceed 3.0% by 2000. United Nations pre—
dictions estimate the ratio of people in less developed
regions to developed regions to be even more lopsided in

2000, about 3.5 to 1.

To compound problems encountered with sheer numbers of
people in underdeveloped countries, income levels and pro—
duction of food is disproportionately low in relation to the
rest of the world. Table 4 contains United Nations estimates
of caloric and protein intake in "low-calorie" and "high-
calorie" countries. To achieve FAO target consumption levels

by the year 2000, the low-calorie regions would have to

realize an annual increase in agricultural production of

37

38
TABLE 4

PER CAPITA DAILY FOOD SUPPLY, 1960 AND 2000

 

 

Kilo- Animal Protein
Calories Grams
l. 1960
Low-calorie countries 2,150 9
High—calorie countries 3,050 44
2. Target — Year 2000
Low—calorie countries 2,450 21

 

Source: Food and Agriculture Organization of the United
Nations. 1962. Population and Food Supply, Basic Study
No. 7. (ref. 30)
about 3.3%. Livestock production would require a slightly
higher growth rate to more than double animal protein in-
take.

To feed 6.5 billion people at current levels of con-
sumption, food production will have to double by the year
2000. Numerous approaches have been put forth as panaceas
for worldwide hunger, some valid, others not so plausible.
Prominent among valid hypotheses are increasing the amount
of land under cultivation and extensive use of fertilizers.(3l)
Bringing more land under cultivation holds some promise
although the effect will be of consequential magnitude only
in certain regions. There are approximately 32.5 million
square kilometers of potentially arable land and another
32.5 million of potentially grazable land in the world with

(32)

about 50% of each catagory utilized. Europe tills nearly

90% of arable land, Asia greater than 80%, the Soviet Union

39
and North America between 50 and 60%, while Africa, South
America, and Australia have 20% or less under cultivation.
Agricultural practices in past years have seen more extensive
land use, particularly in the Far East. More than one—half
of the increase in the world's cereal grain production in
recent years has come from land expansion.(33) Africa,
South America and Australia have the potential of realizing
higher production levels by increasing agricultural land use.
However, Asia, and to a lesser extent Europe, are severely
constrained by current land-use patterns and must pursue other
alternatives. The problem will be especially severe in Asia
where 60% of the people are located and 88% of the land is
used in agriculture. Therefore, a viable alternative for
large areas of the world is employment of more intensive
~agricultural practices.

Increasing yield per unit of land holds potential in
expanding the volume of agricultural production. High-
protein, high—yeild varieties of grains, irrigation and
greater use of fertilizers are a few of the methods available.
Probably the most widely recommended means of increasing
yield is through more intensive use of fertilizers, specif-
ically phosphorus carriers. Production is straight forward,
raw materials are procured with relative ease and the
mechanics of effective application is well known. Barriers
to implementation of high volume fertilizer usage exist in
the massive scale which would be required. The world's
phosphate industry does not have the capacity to supply the

entire world with phosphatic fertilizers at the same level

40
it supplies countries consuming great quantities. If India
were to apply fertilizers at the same per capita rate as
East or West Europe, the needs of that nation alone would be

nearly 90% of the present world consumption.

5.2 World consumption and future demand

Soil enrichment and maintenance with phosphate fertilizers
will serve an important function in future food production.
The volume demanded is a function of a variety of variables,
most notably population and agricultural practices of indiv-
idual nations. Table 5 contains information on world popula-
tion and agricultural consumption of phosphatic fertilizers
for regions and selected countries in 1970. United Nations
estimates of median population in the year 2000 are listed
from which phosphatic fertilizer usage is projeted. Per
capita consumption ranges from 0.47 to 63.05 kilograms
annually with a world average of 5.62.

The United States consumes the largest quantity of any
single nation although Oceania uses the greatest amount of
P205 per capita. The Australian government has subsidized the
use of fertilizer phosphates in a massive program to lessen
dependence on sheep and wool production.(3u) Land is being
upgraded from sheep grazing to cattle grazing and crop land
and diversification has been accomplished and maintained.

Areas employing intensive agronomic techniques generally
consume greater than 10 kilograms per person annually. Regions
of the world with relatively unsophisticated practices use much

less; Asian agricultural consumption (excluding Japan) is

41.

smwuoncmm movsaocfi Amv

 

 

som.m som.m mm mo.mo me.H ma aHzamoo
.moe.m meo.H mm: sm.m mm: omH «onmz< meson
oma.m em: Hmm ma.H was mm . aonmza gamezmo
.mom.m mom mw.mm omm.m mom noooom ocean:
moz.o ssm.m mmm ew.em Hmm.e mom .. «OHmmz< memoz
mo:.ma mom.H mew es.a mom mam aonm<
mme.e . ooo.m omm mm.» oem.s mam ammo
mea.m mam Hm.ma mma.m mmm one:
mwm.m oma mm.mfl moa.m ems . anon
ome.ma sem.m mom om.mfi Hem.» no: maomam
moo.a and oe.m emu soa canoe
MMH mam mm.o on ans 0 camocoocH
mma mam s:.o mm sma Ace copmaxom
mom moo.a oe.o om: mmm voCH
mmm mam.a oo.o mam see cease do .m.a
moo.mm Hem.s mee.m m.H ome.m omo.m <Hm<
mom.m:a esm.om sme.o me.m ems.om ome.m memo:
comooo\mx m.mm maceofl oems 1mm .oonv Anew gas .ooov 1mm .ooov cosooooo
@ coHpQESmcoo @ scapqeswcoo scepmasaom COHuQESmcoo scannedmcoo cofiumHSQom
nonaaaonom nonasaonom ooom noonsaenom meme nonaaaonom oema
mono ooom m0ma ooom oosoeo tom mono egos
osma

 

Amomm weep causes unemsonp mmcomuoa COHHHaEV

ooom m<mw are mom mZOHBoHQmmm Qz<
ouma AonBmEszoo mmNHqHBmmm m9¢mmmomm Dz< ZOHB<ADmOm Qdmoz

m mqm<B

42

less than one kilogram per person annually.

The first set of predictions of phosphate consumption
in the year 2000 from Table 5 is derived from 1970 per capita
usage combined with population forecasts for 2000. Assuming
a static condition in all variables except population, annual
world consumption will increase more than 50% to about 30
million metric tons. From these projections, a viable lower
limit can be established for future consumptive patterns
up to the year 2000. These data are plotted in Figure 8 and
designated "1".

A tentative upper limit can be formulated utilizing
the same procedure. If all the less developed nations of
the world applied phosphates at rates employed by more
developed regions, consumption by the year 2000 would in-
crease by a factor of ten. Assigning a figure of 22.5
kilograms per capita annual consumption (an approximate
median of higher usage regions), the world's annual consump-
tion would reach nearly 150 million metric tons P205.
Regions with levels greater than 22.5 kilograms are held
constant. These data are also plotted in Figure 8 and indi-
cated by "I'". It is doubtful that the world would have
the capability in the year 2000 to annually purchase, trans-
port and distribute this quantity of fertilizer, equivalent
to about 500 million metric tons of raw materials. However,
the range defined by high and low projections creates realis-
tic limits in which a more accurate future use pattern may

be forecast.

Figure 8.

43

World phosphate consumption, 1950—1970,
projected consumption to 2000. (from
Harrel6 and Table 5)

I & I': population based estimates,
Table 5

11: OECD projection

III: U. S. Bureau of Mines projections

 

 

44

 

 

45.35.45.059

48—0.»

 

10v

18
[Oo—

 

 

 

.694.

0% sum omen uomm

45
A number of national and international agencies monitor

the phosphate rock and derivative industries of the world.
The Organization of Economic Co-operation and Development
(OECD), a "free-world" international association, has under-
taken numerous analyses of phosphate rock reserves, phosphate
fertilizer and world trade and consumption of these com-
modities. The Development Center of the OECD has predicted
future use patterns utilizing a more comprehensive structure

(17)

than population—based estimates made earlier. Factors
cited are:

l. estimates of installed capacity of regions for

production of rock, fertilizers and industrial
commodities

2. fertilizer capacities by manufacturing process;
aciduation, thermal and nitrification

3. the rate of installation of future production
facilities

A rate Of growth is forecast for the 1970's based on extra-
polation of historical data within the above constraints.
Total annual world consumption will expand by 7.7% because of
rapid increases in individual developing countries of about
20% and in the Soviet Union of about 11%. The balance of the
century is expected to show an overall slowing of the trend
caused by decreasing rates of increase in the United States
and Europe as well as stabilizing use patterns in developing
nations. Projection of OECD estimates puts consumptive
levels in the year 2000 at about 100 million metric tons P205,
about 15 kilograms per capita. This data is shown in Figure

8 and marked "II".

46

The United States Bureau of Mines is another organiza-
tion which scrutinizes mineral commodities and formulates
predictions of future consumptive patterns. Phosphate demand
has been estimated by the Bureau on the basis of projected
historical trends influenced by limitations of financing,
transportation, distribution and utilization capabilities.(l6)
Continued grthh at the rate of 6% experienced in the 1950's
and 1960's would place 2000 annual consumption at about 125

million metric tons P20 Investigations cite the uncertainty

5.
of projections caused by problems of a technical, political

or economic nature encountered by developing nations. There-
fore, a lower growth rate of 4.2% has been formulated placing
2000 levels of consumption at about 98 million metric tons

P205 or 15.7 kilograms per person. This trend is reflected

in Figure 8, designated "III".

Additional activities by individual nations could
significantly affect development of world phosphate consump—
tion and Shift projected curves. These items are by their
nature uncertain and consequently are not numerically in—
cluded in calculations of long-run demand. The distribution
of phosphates under "free-market" conditions varies regionally.
Present industrial use by the United States and other developed
areas is as great as 25% while other regions consume a very
low percentage in industry. (Table 6) Although different
final production methods are utilized for agricultural and
industrial phosphates, both draw on the same pool of resources

and require the same initial transportation, extraction

47
TABLE 6

DISTRIBUTION OF PHOSPHORUS IN REGIONAL MARKETS

 

 

Agriculture Industry
North America 74.9 25.1
West Europe 78.1 21.9
Japan 84.4 15.6
East EurOpe 94.5 5.5
Oceania 97.2 2.8
Others 98.1 1.9
TOTAL 84.7 15.3

 

Source: Organization for Economic Co-operation and Develop-
ment, 1972. Phosphate Rock and Phosphatic Fertilizers
in the World. (ref. 17)

and beneficiation. Countries in which consumer demand is

given greater recognition may experience competition for

resources.

A consideration of greater potential impact is the
possible, albeit unlikely, implementation of massive fertili-
zer programs in those countries with a very large population
and very low present consumption levels. Evidence of such
practices was shown earlier by the Australian government's
phosphate fertilizer subsidy program. The People's Republic
of China, India, Pakistan-Bangladesh and Indonesia collectively
represent 43.7% of the world's people in 1970 and 44.6% of 2000
estimates. (Table 5) All of these nations consume less than
one kilogram P205 per person annually in agriculture. One or
more of these countries rapidly adopting intensive agricultural

practices comparable to those of North American or Europe would

48

cause a marked deviation in world consumptive patterns,
severely affect the international price of raw fertilizer
materials and place considerable stress on the production

capabilities of the world phosphate industry.

5.3 United States cOnsumption and future demand

Consumption of phosphorus in the United States has
evolved into a sophisticated, highxnxunmg operation. The
pattern of use and diversity of end products is typical of
developed nations of the world. The U. S. produces and
consumes more phosphates than any other country and channels
the greatest amount of phosphatic materials into industrial
usage. (Figure 7 and Table 6) The structure of the indus-
try as a whole is unique compared to most of the world in
that it exhibits vertical integration, possessing sizeable
reserves and facilities for utilization to the point of
application.

Annual percentage increases in domestic consumption
will be significantly lower than the rest of the world
while absolute values will continue to be high. The potential
role of the United States in supplying world demand for
phosphatic fertilizers shifts projections upward by as much
as 100%.

The U. S. population in 2000 is estimated at 305 million‘
(Table 5). Combined with 1970 per capita consumption the
resulting projections place agricultural and total annual
'consumption at 8.8 and 11.1 million metric tons, respectively.

These data are plotted in Figure 9, designated "I" and "I'".

Figure 9.

49

United States phosphate consumption,
1950—1970, projected consumption to
2000. (fr m U.S.D.I., Minerals Year-
book, 1971 and Table 5)

I & 1': population based estimates

II & 11': U. S. Bureau of Mines projections

III: U. S. Comm. on Population Growth and
the American Future projections

 

 

50

. . . N
82
. onu—
one
. .. . F
Oma—

 

 

455530.294
1.5.0...
H' I I I I I I IOoOIOOOIOOOIO‘OV
~H.I|l.n.ll..lil l.l.l.l.l.|\u.\n‘l\a“h.ql.lo .
\\\\\\ \o“0\
11111 \.. . .
‘1‘ \.. o
‘1‘ \o .o o
111 \. . .
\\\\\ \\o. o o
H. \\\\\ \ \. . . . . Op
\ . . .
\ . . .
~H|\\. . . . .
"I ..
ON
on

d
SNOJ. OHM!" NOI'I‘IIIV

to;

51

Like the rest of the world, the key determinant of demand

is population, although the effect is significantly greater
in the United States. The mature U. S. industry precludes
any implementation schemes which could double or triple con—
sumption in a Short period of time. Additionally, a greater
share of total U. S. consumption is directed toward consumer
oriented products, and involved in industrial processes, both
of which are subject to pOpulation pressures and demand.

The Bureau of Mines has forecast growth of phosphate
consumption to the year 2000, correlating population growth
with fertilizers and detergents. Gross National Product is
used as an indicator of demand for animal feed supplements
and industrial uses other than detergents with technical and

(16)

other contingencies included where applicable. These
data are summarized and presented in Table 7 and median values
are illustrated in Figure 9 (II and II').

The 1970 per capita rate of 28.88 kilograms annually
is expected to be maintained in future periods resulting in
about 17 million metric tons P205 annually. The role of the
U. S. in feeding the world's people now and in the balance
of the century could possibly double demand to about 33
million metric tons.

Demand for detergents and soaps is also derived from
population statistics. However, the use of phosphorus in
these products is threatened by reduction or prohibition
of use in relation to environmental degradation and could

possibly result in demand dropping to zero by 2000. There-

fore, a conservative maximum estimate of about one-half

52
TABLE 7
PREDICTED UNITED STATES DEMAND FOR PHOSPHORUS

IN THE YEAR 2000
(million metric tons P205)

 

 

 

 

 

Low Median High
Agricultural:
Fertilizer 16.91 24.87 32.82
Industrial:
Detergents and soaps 0.00 0.26 0.52
Plating and polishing 0.88 0.95 1.01
Animal feed 0.63 0.76 0.88
Other 3.79 3.91 4.03
TOTAL 22.21 30.75 39.26

 

Source: Lewis, R. W. 1970. Phosphorus, pp. 1139-1155.

In Mineral Facts and Problems. U. 8. Dept. of

the Interior, Bureau of Mines, Circular 650.

(ref. 6)
million metric tons P205 is offered in the event of feasible
phosphate removal from sewage effluent.

There are no substitutes for phosphorus in animal feed
and it is estimated that future demand will correspond with
GNP growth, resulting in about 880,000 metric tons P205
annual consumption. Similarly, no technological shifts are
foreseen for other industrial uses and demand is expected
to increase to about 4.9 million metric tons P205 by 2000.

A final evaluation is offered which bases findings of
mineral forecasts on comprehensive macroeconomic input-output

relationships. In reports to the U. S. Commission on

Population Growth and the American Future, considerable

53
weight has been given to economic and technological aspects
of phosphorus, production and use of commodities and domes-

tic supplies.(35)

Projections of phosphate demand are
preceeded by reviews of population dynamics and United
States participation in world trade. The conclusion reached

places 2000 annual consumption at 26.7 million metric

tons P205, illustrated in Figure 9 (III).

6. DEPLETION 0F PHOSPHATE RESERVES
6.1 World reserves

Knowledge of phosphate rock reserves has increased
regularly in the past 75 years. Estimates of known reserves
in 1925 were 6.4 billion metric tons, which was increased
to 16 billion in 1942.(36) In the early 1950's, the figure
had risen to 43 billion metric tons<37> and further to 50
billion in the 1960's.(23) Compilation of current data
contained in Table 1 establishes a current estimate of
phosphate rock at 159 billion metric tons representing about
43 billion metric tons P205.

Phosphate rock has been regarded by many as a commodity
with no end, in much the same manner other fund resources
have been viewed and consequently mismanaged. Reports of

(2)

phosphates depict reserves as vast, of infinite duration,
giving rise to no questions of depletion or problems,(38)
and others employing similar adjectives. The time of
depletion of phosphate reserves has been estimated to occur
as rapidly as the year 2200,(39’ 40) and as far distant as

(41)

1000 years. Reserves are more than adequate to satisfy
short-run demand for the next 200 years. However, a fund

resource is by definition finite and the escalating pressure
on phosphate resources may make depletion an eventuality in

a relatively short period of time.

54

55

The actual date reserves will be exhausted is dependent
upon the volume of materials consumed. Assuming the fore-
casts up to the year 2000 are credible, projections from
that point have been made at various rates of growth for
annual world consumption. Additional assumptions are re-
quired prior to formulation of the estimates:

1. Cumulative consumption for the period 1970-2000

will be about 1,823 million metric tons P205, there-

by reducing reserves to 41,147 million metric tons

P O .

2 5

2. Total reserves have been increased 15% to offset

future discoveries, based on past exploration and

potential unknown reserves in undeveloped regions

of the world. The base figure is thereby adjusted

to 47,319 million metric tons P205 in 2000.

3. Annual consumption for the base year is estimated

at 100 million metric tons P205 from projections in

Figure 8.

4. Capacity of the industry to mine and refine rock
is sufficient to satisfy demand.

The combined result of the base data and assumptions is shown
in Figure 10. The five curves plotted represent growth rates
from zero to four percent per annum.

Figure 11 contains curves representing depletion of
world phosphate rock reserves corresponding to individual
growth rates in Figure 10. At zero rate of growth from the
year 2000, the maximum length of time until reserves are
exhausted is about 505 years, or until about 2475. The
minimum time, derived from the four percent rate of increase,
is about 105 years, or 2075. Neither of these appear
plausible although values within the range give a more
realistic estimate, possibly 0.5 to 1.5%, placing the date

somewhere in the latter half of the 22nd century.

MILLION METRIC TONS no,

 

 

 

‘KNIOOOE “%
.1
50.0004
. 3%
10,000:
1
5P”: 2%
1.000:
1 1%
5004
100 0%
2600 2150 2200
YEAR
Figure 10. Projected rates of growth of world phos—

phate consumption.

BILLION METRIC TONS P,0,

 

57

 

 

50
404
30‘
0%
20'
1%
10-
4 .
0 v n I w
2000 2050 2100 2150 2200
Y E A R
Figure 11. Schedule of depletion, world phosphate

rock reserves.

58

6.2 United States reserves

Patterns of consumption are forecast from the year 2000
for the United States in the same manner utilized for world
resources. Similarly, fundamental assumptions are made prior
to derivation of estimates:

1. Cumulative demand for the period will be 517

million metric tons, reducing reserves to 11,494

million metric tons P205.

2. Total reserves are increased 15% to offset future

discoveries, adjusting the base figure to 13,218

million metric tons P205.

3. Annual consumption in the base year is estimated

at 27 million metric tons P205 from projections in

Figure 9.

4. The industry will be capable of supplying demand.
Annual growth rates from zero to four percent are projected
from base year 2000, shown in Figure 12. Figure 13 contains
curves representing depletion of U. S. phosphate rock re-
serves corresponding to the various growth rates in Figure
12. At the zero percent rate, reserves could be expected
to endure for another 520 years to about 2490 while the

four percent rate would deplete reserves by about 2075,

105 years hence.

6.3 Contingencies

There are a number of issues surrounding phosphorus
resources which confound smooth projection curves, both
aggravating and enhancing the status of reserves. Phosphorus
on the sea floor exists in the form of teeth, bones and

nodules. Detrital material of this nature is remarkably common

on the bottom, consisting of tricalcium phosphate contain-

.(42)

ing about 34% P205 Although they could not feasibly

MILLION METRIC TONS P20,

59

 

 

 

10,0001- 4 x 3 x
5,000-
.
i
2
1,000- X
I
I
500‘
1 X
1001
50 -
0 96
10 I T T 1
2000 2050 2100 2150 2200

YEAR

Figure 12. Projected rates of growth of United
States phosphate consumption.

BILLION unmc TONS 750,

15.01

12.5‘

gs
?

N
a
1

9'
C)
1

2.5-I

4%

60

1%

2%
3%

 

 

 

Figure 13. Schedule

T t V 5

2160 2300

r

YEAR

of depletion, United States

phosphate rock reserves.

61

be mined alone, they could be recovered as a byproduct from
any deepnsea mining operation. Phosphorite nodules are com-
prised of tricalcium fluorcarbonate phosphate which forms

on sand, gravel and calcareous organic remains. The size
varies from one millimeter up to one meter and generally
consists of less than 30% P205.

Sea floor deposits of phosphate occur in areas where

detritus and other sediment is excluded, usually by isolation
on tOp of shallow banks or at the seaward edge of continental

shelves.(u3)

Known deposits are found off Southern California,
off Peru-Chile, off Southeastern United States and near the 1
Republic of South Africa. Estimates of teeth and bones are

not available and only elementary guesses have been made
concerning ocean—bed deposits, placing U. S. reserves at a
potential one billion tons of rock. These data are not
included in reserve estimates offered earlier due to in-
sufficient information concerning location, grade and
feasibility of extraction.

Other factors exist which do not affect the volume of
known reserves and are not included in the framework of
projections made to the year 2200. Rather they influence
the economics of mining and refining procedures.

Florida has produced more than 80% of the United States'
output of rock phosphate for domestic consumption and export
markets for the entire history of the industry. This position
of prominence was aided by proximity to low-cost bulk trans-

portation via ocean vessels. Conversely, the Phosphoria

Formation in the western states is approximately 1,050

62
kilometers inland from the nearest deep—water port. As

the United States draws more heavily upon these reserves,
inherent higher freight costs will be incurred.

Florida mines have similarly benefitted from the geology
of the region's formation. The ratio of overburden to matrix
is a prime determinant in the economic feasibility of a given
mine. The ratio of Florida's mines is low, about 1:1 or
1:1.5, allowing exclusive use of open—cut mining. Much of
the Western Phosphoria Formation, however, is contained in
rugged mountains with much folding and intense deformation.
Future extraction will necessitate underground mining with

(44) This factor should be a

consequent increases in cost.
salient point in evaluating future exploitation of phosphate
resources in the United States as nearly one—half of U. S.
reserves are found in western deposits and about 35% of

total U. S. production will require underground mining.

In addition to presence and accessibility of phosphates,
the quality of rock produced is of significant importance.
Mining in the United States has experienced an overall down-
ward trend in the grade of rock extracted in the last 30
years. Figure 14 illustrates the ratio of grades of rock
produced by each major center and the United States. The
greatest percentage of high quality rock produced was in
1950 where the ratio of highzmediumzlow grade rock phos-
phate (>34%, 28-34%, <34% P205, respectively), is about 5:4:1.
The ratio derived from recent production is about 1:8:1,

reflecting a progressively lower percentage of high quality

material available.

 

63

Figure 14. Relative quantities of high, medium,
and low grade phosphate rock pro-
duced in the United States. (from
U.S.D.I., Minerals Yearbook, 19718)

 

 

 

Percent of Total Production

WESTERN
STATES

 

 

 

TENNESSEE

 

 

 

 

 

 

FLORIDA

 

 

 

100

TOTA L
U. S.

 

 

 

 

 

65
Florida production typifies the condition of the indus-
try. In the same time period, the ratio has progressed
from about 5:520 in 1950 to 1:9:0 in 1971. The implications
of the trend shown in Figure 14 are evident; less high grade
rock is available for production, requiring greater
amounts of all raw materials to furnish the same unit of

finished phosphorus.

7. PHOSPHORUS REUSE

A final consideration which may affect resources
is recycling of phosphorus presently classified as waste.

The potential impact of recycled phosphatic materials is
far-reaching; reducing surface water degradation brought
about by current methods of disposal, altering consumptive
use patterns of finished products in agricultural application
and influencing levels of production of phosphate rock and
depletion of reserves.

Natural and cultural pathways of the phosphorus cycle
have been illustrated in Figure l. Man's influence is in
effect a short curcuit or sub-cycle of the natural process.
The natural cycle requires millions of years from the time
of deposition of materials to geologic uplife, completing
the process and resulting in available formations. Man's
current pattern of use, however, has shortened the
cycle by dispersing phosphorus in low concentrations to
available bodies of water. Continued unwise use of the
resource will result in reducing most of the world's supply
of phosphorus to a "non-available" status where recovery
would require very high energy expenditures.(u5)

Natural and cultural sources of phosphorus entering
U. S. surface waters are contained in Table 8. The principle
cultural sources are domestic sewage and runoff. These

activities contribute more than 60% of all phosphorus dis—

charged to surface waters or about 50% more than that of
66

 

67

monogamono mo Hm>oEop $om ADV
0mm Rom u xoop mo oommw owmmo>m Adv

Am: .mopv .woma sopmz .m .02 .m .Ho> .mwoaocnooe Ugo oocoflom prcoesopfi>cm
.npSOLU Hmwfl< mmooxm mo Emanomm map on nomopaa¢ ofiaomecoz < .< .m .QOmswpom "oonsom

 

 

 

 

o.ooa mam.msm.a osw.mmm mmompom age gaeoe
N.Hm :Hm.moo.m mmm.mws mmm.a:m gamaeqpo qaeoe
w.mH Hza.mmm m:s.msa oma.~s mpoaemmo Hmefis<
H.0H oms.mm: wam.wma omm.om coma empm>auazo
m.H m:w.mw :mwnma mmm.m puma coop:
coocsm
ADV opmwz wcfinmmz
s.mm mow.:mm.H H::.sm: oms.mma eooo .smesn mmwmzmm
aampegpo
m.mm mmm.mm: mHo.sHm oamseaz qaeoe
s.mm mm:.am: oaz.mwfi coocsm ammo pmmpom
m.: www.mm mmm.:m mpcmfim afipasea
w.o Asm.m mam.: Hamccfimm
q<mse<z
Hmpoe mo Amv pcoam>flsvm momm monoammocm
pcoopom Xeom opmcomosm

 

mmMB<3 mo<mmbm .m

Amcou oappoev

.D UszmBzm mbmommmomm mo mmombom

m mqm<8

68

the natural system. Domestic sewage represents the largest
share of phosphorus discharged, 35.7% of the total.

The unfortunate consequence of massive flow of nutrients
to lakes and streams is degradation of the receiving waters
through accelerated aging or eutrophication. Eutrophication
is a natural process which involves the biological produc-
tivity and consequent aging of natural bodies of water. The
effects are the same, whether the process proceeds naturally
or is hastened by activities of man. They include excess
growth of algae and other plant life, depletion of dissolved
oxygen, undesirable tastes and odors and a general lowering
of aesthetic values.(u7)

Carbon, nitrogen and phosphorus are generally considered
to be limiting nutrients in aquatic productivity. While
carbon and nitrogen have an atmospheric reservoir available
to the aquatic environment, phosphorus is circulated almost
exclusively by processes of erosion, sedimentation and bio-

(48) Discharge of wastewater containing

logical activity.
soluble phosphorus effectively creates a subcycle in the

natural routine and increases the rate of aging in aquatic
environs.

A 1971 survey of "problem lakes" conducted by the
Wisconsin Water Resources Center specified 353 lakes in the
United States which were reported to be in advanced eutrophic‘
states with nuisance algal growth and/or aquatic vegetation.(u9)
Municipal sewage treatment plant effluent was recognized

to be the cause in over 75% of those lakes evaluated. A

summary of this facet of the study is as follows:

69

Number of eutrophic lakes receiving

 

municipal 194 5,328 square kilometers
feedlot discharge 14 299 square kilometers
other discharge 145 1,431 square kilometers
TOTAL 353 7,058 square kilometers

Domestic sewage is the best source available for man-
ipulation and recycling via agricultural spray application.
Phosphorus in sewage is derived primarily from human excre-

ment and detergents. The fraction from human excreta varies

 

F
with diet, usually 454—545 grams per person annually while i
the contribution from detergents is 1,362—l,589 grams.(50)
Legislation by several state and local governments in the
early 1970's now regulates levels of phosphorus in detergents E

and consequent input to receiving waters. The measures

reduce the level of phosphorus in sewage although the increase

in population served by municipal sewage treatment systems

has negated the overall effect to a degree. During the period

from the mid-1950's to the late 1960's, 40% of the increase

of phosphorus resulted from an increase in the number of

people discharging into municipal systems rather than greater

phosphorus usage in personal products.(50)
Agriculture, the largest consumer of refined phosphatic

materials, represents the most viable end use for phosphate

in wastewater. Recycling on moderate scales has been practiced

since the late 1800's. Many American and foreign projects

utilize some combination of reclamation, reuse and recycling

of wastewater. One well known project was initiated at

Pennsylvania State University in 1963 in which secondary

70
treatment plant effluent is sprayed on crop land and mixed

hardwood and conifer woodlots. The results have been in-
creased vegetation growth, prevention of discharge of pollu-
tants to local receiving waters and contribution of high
quality water to the local ground water supply.(51)
Muskegon, Michigan provides a second example of reuse

schemes. A comprehensive plan utilizes the county's
municipal and industrial wastes in a lagoon—irrigation sys-
tem for growing crOps on sandy soil normally considered non-

agricultural land. Wastewater reuse has been used in this

case for improvement of nutrient—deficient soils as well as

 

waste disposal and elimination of effluent discharge into

Lake Michigan.(52)

The average composition of municipal sewage and the
effect of various treatment processes on phosphorus is listed
in Table 9. The volume of phosphorus available for reuse
is relatively unaffected by primary and secondary treatment
processes although effluent from pond systems contains about
one-half that of the other systems.

The phosphorus concentration of untreated sewage given
in Table 9 is a range of 6 to 20 mg P/l. The estimated volume
of domestic municipal wastewater generated annually in the
United States is 29 billion cubic meters (175 million people
served, 0.454 m3 water/day, 365 days).(5u’ 55) The resulting
range of phosphorus contained in the municipal sewage is
174,000 to 580,000 metric tons while equivalent values of
are 399,000 to 1,329,000 metric tons. These quantities

represent 6.7-22.3% of P205 consumed as fertilizer in the

United States during 1970 (Table 5).

71

TABLE 9

AVERAGE EFFLUENT CHARACTERISTICS OF
VARIOUS TREATMENT FACILITIES

 

 

 

Treatment

Primary Secondary

(ms/l) (ms/l)
Total Dissolved Solids 1,402 1,138
BOD 152 36
Total Nitrogen 37 21
Chlorides 461 200
Sulfate 180 300
Alkalinity 635 587
Sodium 329 239
Potassium 22 16
Calcium 96 75
Magnesium 34 45

 

Phosphorus mg/l

Raw Sewage 6—20
Primary 11.0
Secondary
Trickling filter 13.0
Activated sludge 12.9
Pond system 6.7

 

Source: Pound, C. E. and R. W. Crites, 1973. Character-
istics of Municipal Effluents. (ref. 53)

72
The concentration of nutrients in industrial wastewater
has been investigated by Vollenweider and found to contain
from two to nine times as much phosphorus as that found in

(56)

municipal sewage. The highest levels are contained in
wastewater from food processing operations as beet sugar
processing, breweries, slaughterhouses and others. Concen—
trations range from 2 to 274 mg P/l with a mean value of
approximately 54 mg P/l for the food industry as a whole.

The volume of wastewater produced annually by food processing
operations is about 4.5 billion cubic meters (205 million

54) '

people, 19.8 m3/person/year).( The corresponding values

for phosphorus and P205 are 240,000 and 550,000 metric tons,

 

respectively, which represents 9.2% of P205 consumption as
fertilizer. Combined with estimates made for municipal sew—
age, the range now represents 15.9 to 31.6% of P205 consump-
tion in agriculture and the equivalent of 8.7 to 17.2% of
the rock phosphate produced in the United States in 1970.

Externalities associated with a nutrient reuse system
are significant and numerous. Public health is an area of
concern, both from potential ground water contamination and
the affect of airborne pathogens. Soil and vegetation
response requires monitoring as nearly all chemical elements
are toxic at some concentration. Public acceptance may also
influence the success of reuse programs because the private
farmer is the final step in the process.

These and the many other factors unique to each general
location and wastewater source are outweighed by the cost

of application, particularly the Operating cost incurred in

73

transmission of effluent to the reuse site. For example,
the additional operating cost to a system of 57,000 cubic
meters per day capacity (15 MGD) pumping effluent 1.6
kilometers (1.0 miles) is about 50% of total treatment costs.(57)
A significant portion of the cost increase, about 10%, is
derived from power required to pump and distribute effluent
throughout the system. One-half of power requirements is
used in transmission to the site alone. As the distance from
the treatment facility to the site increases, expenditures
of energy increase at a considerably higher rate, constituting
a much larger percentage of total cost. The implementation
of large scale, long distance recycling programs will be
inhibited by current high energy costs. Alternative energy
sources, possibly nuclear power generation, could lower
barriers and aid in promotion of effective reuse—recycling-
reclamation efforts.

Part II is concerned with energy consumption of processes
which contain as a final step the application of phosphorus
on agricultural crops. Energy requirements are outlined from
the point of mineral excavation to use on farm land. A
similar framework is constructed for transmission of sewage
treatment plant effluent to the farm via pipelines and irriga-

tion equipment.

 

PART II. ENERGY CONSUMPTION

1. INTRODUCTION

In 1970 the United States utilized the equivalent to

20,000 billion kilowatt-hours of energy, 96% of which origi-
(58)

nated from fossil fuels. Demand for energy has increased

at an annual rate of about 4% from 1950 to 1970 and is ex- L

pected to continue to increase to about double present con—

(38)

sumption by the year 2000. Demand for electricity, which

 

represents about one-third of all fossil fuels consumed, is
projected to quadruple in the same period.(59)

Pressure on finite resources of fossil fuel from esca-
lating demand will result in rapid depletion. As stores
decline, the costs of obtaining fuel from both foreign
and domestic sources will rise rapidly. The net effect has
resulted in a situation of increasing severity, frequently
termed the "energy crisis."

Energy used in mining, the chemical industry and
agriculture constitutes a significant portion of total U. S.
requirements. Combined mining operations account for 10%
of total industrial fossil fuel requirements and 7% of
electricity generated while the chemical industry uses 25%
of all industrial electricity.(38) Agriculture is an
important consumer of liquid petroleum, about 10% of total
United States usage, and about 3% of total electricity.
Efficient power usage at this magnitude is crucial to both

75

76

resources and profitability.

Those operations and processes which require large
inputs of energy will become increasingly influenced by
conditions of reduced supply, increased demand and consequent
higher costs. Within this context, the use of fertilizers
will be compared to the reuse of wastewater for plant nutrition.
The comparison presented is a non-monetary evaluation of
required energy to mine, refine, transport and apply a given
unit of phosphate derived from mineral rock as opposed to

obtaining the same quantity in wastewater from a municipal

 

sewage treatment facility. Triple superphosphate, the fer-
tilizer consumed in greatest quantity, is used in the example
as the phosphorus-carrying fertilizer.

A mid-western farm situated 50 kilometers from Clinton,
Iowa is presented as a typical recipient of plant nutrients
from characteristic facilities in the United States. The
location was chosen for a number of reasons, the first of
which concerns transportation. Clinton is an equal straight-
line distance, about 1800 km, from the center of the Florida
phosphate producing region at Tampa and the center of the
western region at Montpelier, Idaho. Clinton is also one of
Iowa's major riverports on the Mississippi River, presenting
a comparison of overland rail shipments and bulk shipments
via water. The 50 km distance from Clinton to the hypothetical
farm is assumed to represent normal movement of fertilizers
from distribution centers to consumers. For wastewater reuse
projects, Clinton has a population of about 38,000 people,

capable of producing 6.3 million cubic meters of wastewater

77
annually containing 38 to 126 metric tons of phosphorus
equivalent to 87 to 289 metric tons P205.
The rate at which plant nutrients will be applied to the
hypothetical farm is taken from U. S. Department of Agricul-

ture recommendations which range from about 40 to 50 kilograms

P205 per hectare (36—48 pounds/acre). Usage by general crop

 

classification is as follows:(60)
close—growing (wheat, barley) 39.6 kg P205/ha
permanent pasture 43.9 kg P205/ha
hay 49.9 kg P205/ha
intertilled (corn, soy beans) 51.1 kg P205/ha

Phosphatic fertilizer usage is assumed to be 46 kg P205
per hectare. A11 processes evaluated culminate in applica-
tion of nutrients to a ten-hectare plot of land, requiring

a total of 460 kg or 0.46 metric ton P20 which equals the

5
content of one metric ton of 46% P205 triple superphosphate.
An equal amount of phosphorus derived from wastewater is
applied to the same theoretical plot of land.

The segment of the example producing fertilizer from
mineral phosphates begins with a survey of thee different
types of phosphate mines; Western underground mining, Western
surface strip mining and Florida strip mining. the manufac- ‘
ture of phosphoric acid, a basic component for triple super-
phosphate, is produced by the wet process or aciduation and
the thermal process with electric furnaces. Production of

triple superphosphate proceeds acid manufacture. Transport

of raw and finished materials and the application of

78

fertilizer to the soil constitutes the last step. A summary
includes rock and fertilizer movement from the West and
Florida, transported by alternate methods and applied in
Iowa.

Phosphorus from wastewater is traced from the waste
treatment discharge to the farm. Requisite steps in the
process are collection and storage in lagoons, transfer to
regional delivery points adjacent to farms and distribution
to individual farms. Once on the site, application of the

water is accomplished by a fixed-set irrigation system

 

(underground piping) or by a center—pivot, portable system.
The comparison of alternative methods encompasses con-

sumption of energy by established operations, excluding

capital outlays. The power requirements of individual

operations is discussed followed by summarization.

2. FERTILIZER MANUFACTURE

2.1 Phosphate rock mining

Extraction of mineral phosphate is undertaken by surface
or strip mining and to a lesser extent by underground methods.
Ore in Western deposits, characterized by Figure 15, is
removed by both methods. Subsurface mining is employed
where beds at greater depths permit while surface stripping
is employed for shallower outcrops. Western mining is selec-
tive, removing high-grade ore for shipment and stockpiling
low content rock for future use.

Rock from the Central Florida region differs from Western
phosphates in that it is contained in a matrix of sand and
clayey—sand. While Western phosphates require little or no
treatment following extraction, almost all Florida rock is

(61) The ratio of

(62)

subjected to some form of ore dressing.
waste to ore is about 30:1 in Western operations where
that of Florida mines is about 7:1.(63) However, waste

from Western mines is removed by strippers prior to excava-
tion of ore whereas more than one-half of the Florida mine
waste must be treated with the phosphate rock. To obtain one~
unit of Western phosphate suitable for fertilizer manufacture,
about 30 units of overburden and waste are removed. To

obtain that same unit from Florida rock, 6.75 units of over-

burden and matrix must be excavated and three units hydrau—

lically transported to a treatment facility. There it is
79

 

8200'-

8100'-

 

80

 

 

Waste
B C D
Wells Rex
leostono Chart
Cap Rock ‘Wasto
l l 1
0 25 50
METERS
Figure 15. Typical section of the Phosphoria

Formation in southeastern Idaho.
(after Service and Popoff15)

"A" Bed: +31% P20

5
"B" Bed: +27% P205
"C" Bed: +20% P205

"D" Bed: 18% P205, interbedded layers of
high-grade phosphate and clay seams

 

 

 

81
processed, concentrated to one unit, dried and stockpiled.

Estimates of energy consumption by the three mining
techniques are represented in Table 10, followed by a brief
explanation of each. Formulation of required inputs is
difficult and economic evaluation of prospective mine sites
are often accompanied by contingency factors as great as 25%.
Generalizations are not applicable to Western phosphate
deposits, even within a single region, because of intense
deformation of phosphate-bearing strata. The following are
examples of mine operations with estimates of power require-

ments as an indicator of approximate consumption.

 

Western strip mining

 

An investigation by the Bureau of Mines evaluated a
stripping operation of phosphoria outcrop in Caribou County,

Idaho.(62)

Phosphatic shale was removed from the deposit

and transported 2.4 kilometers by truck to a collection point.
Drilling, blasting, ripping, stripping, loading and hauling
required about 130 kwhr per metric ton of 31.5% P205 rock
produced. The actual power consumed was about 3.9 kwhr

per mt of material handled but 32 mt of waste for every ton

of ore produced combined to give the value shown.

Western underground mining

Underground mining is distinguished from surface mining
in a number of ways. Initially, the deposit must be developed,
that is, shafts must be driven into the body of rock for ore
removal. An example of an underground phosphate mine, the

Arickeree Mine in Rich County, Utah, is shown in Figure 16.

82

TABLE 10

ENERGY REQUIREMENTS OF PHOSPHATE
ROCK MINING OPERATIONS

 

 

 

 

 

 

 

 

 

 

 

Energy
Ref. Source kwhr/mt Rock
Western Surface Mine
stripping 62 oil 152.4
electric 5 6
158.0
haulage—ore 62 oil 157.4
—waste oil 10.3
167.7
TOTAL 325.7
Western Underground Mine
extraction electric 155.0
haulage-ore oil 90.0
-waste oil 360.0
450.0
TOTAL 605.0
Florida Strip Mine
stripping 64 electric 12.4
hydraulic transport- 65
monitors electric 14.5
water supply electric 2.4
16.9
beneficiation 62 oil 50.1
electric 50.7
100.8
drying 63 oil 344.5
conveying 66 electric 0.7
TOTAL 475.3

 

83

 

 

 

 

 

 

 

ourcnop ..
.. 5'
£‘ ~:
-
x7
1 ’1’!
I’,”’
l’ ’
’ I
l”’
WINZE
I”
I
I”’
,3! ADIT
I’I
I I
\I I-
M
x?"
I ,’
I’,’
7951?:
I T 1
0 25 50
METERS

Figure 16. Section of inclined winze, Arickeree
Phosphate Mine Rich County, Utah.
(after Wideman67)

84
This location.contains one inclined winze (main shaft) and
three adits (horizontal shafts) which lead to the side of
the mountain. Total length of these shafts is about 350
meters, each about 1.8 by 3.6 meters, resulting in 18,485
mt of waste material which was excavated prior to production
of the first ton of rock phosphate. Following development,
drifts were driven off the winze at 90 degrees into the phos-
phate deposit. Broken rock is hoisted from lower levels to
the 100 level adit, moved out to the surface and transported ‘5,-
by truck to a collection center.

Power requirements of underground mining operations are La:

 

difficult to determine and often unavailable for specific
minerals. Data regarding phosphate mines and related energy
usage are incomplete and a series of underground mine examples
are presented from which a reasonable approximation of re-
quired energy may be derived. Mines removing a variety of

minerals in the western phosphate producing region are as

 

follows:

Mine kwhr/mt Rock
Example Reference Rock Type Excavated
l 68 Variety 33.2

2 69 Granite 59.7

3 ' 70 Granite 94.3

4 71 Sandstone 95-5

5 shaft 72 Sandstone- 715.1

Siltstone
drift Halite 480.7

85

The lowest value is an average of Western metal mines re—
quiring little development. The highest is a vertical shaft
lined with concrete for an atomic test in the New Mexico
desert. Two of the examples, numbers 3 and 4, approximate
the conditions of the Arickeree Mine in geologic nature and
depth from which an estimate of 100 kwhr per mt is taken.
The development of the Arickeree Mine required an es—
timated 1.85 million kwhr, (18,485 mt @ 100 kwhr/mt). As
the amount of ore removed increases, the initial cost of
development is spread over the life of that particular mining
operation and the total energy consumed per ton decreases.
Therefore, the first 1000 mt of phosphate rock will require
1948.5 kwhr per mt, the second 1000 mt, 1024.3 kwhr per mt,
and so on until the deposit is depleted. After about 35,000
mt of rock production the energy consumed per ton is equal
to that of strip mining. Energy consumption is estimated
to be about the same as that given for surface mining, or
155 kwhr per mt. A greater volume of waste material exca-
vated and hauled from the underground mine is responsible
for the disproportionate consumption of energy by the two

western mines.

Florida strip mining

 

Mining in central Florida is simplified compared to
that of the western states because of the geological nature
of the area. The matrix of phosphatic materials averaging
about 6 meters is located above the flat Hawthorne limestone
formation of that region with an overburden of about 7.6

meters above the matrix.

86

Mining in the Bone Valley Formation is accomplished by
what is commonly referred to as the "Florida phosphate mining

"(73)

procedure. Stripping is undertaken by large electric
walking draglines which first removes the overburden followed
by excavation of the matrix. The matrix is put into a
shallow sump where monitors direct jets of water at high
pressure to break up lumps and create a slurry. The slurry
is then pumped to processing plants at distances up to 12
kilometers. At the plant the matrix undergoes beneficiation,
a series of processes where the material is washed, deslimed
(removal of fine clay particles), sized and subjected to
flotation (recovery of minute particles of phosphate). The
concentrated rock is dried in oil—fired rotary—drum dryers

and conveyed to stockpiles for shipment to phosphoric acid

plants.

2.2 Phosphoric acid manufacture
Phosphate rock is a low-value, high-volume commodity

and the location of phosphoric acid production facilities

is primarily resource oriented. Nearly 70% of wet—process

acid plants are located in close proximity to mines in

Florida, North Carolina and Western States with an additional

14% located near Gulf of Mexico ports to take advantage of

(41)

low—cost ocean transportation of Florida rock. Thermal
process acid plants are located in a similar manner with 87%
of total production capacity adjacent to mines. Transporta-
tion of rock from stockpile to acid plants is usually done
by conveyors which consume negligible amounts of energy,
(66)

usually less than one kilowatt-hour per metric ton.

 

87
Following receipt of raw phosphatic materials, the rock
is ground and crushed to uniform size, sorted and classified.
Power requirements for grinding and related operations is
dependent on the type and condition of rock phosphate and
the desired finished product. Consumption is generally 15

to 18 kwhr per mt.(7u)

Weteprocess phosphoric acid

 

Conversion of concentrated phosphate rock to phosphoric
acid is accomplished by two general methods, the wet process
and the thermal process. The production of wet-process acid
involves aciduation of rock followed by agitation of the
mixture and curing. In an operation characteristic of the
industry, one metric ton of phosphate is produced as 85%
phosphoric acid (H3P0u) containing 54% P205 and consuming
197.5 kwhr.(75) Raw material required is 3.08 mt of 31%-
32% P205 rock and 2.30 mt 100% sulfuric acid (H2SOM).
Sulfuric acid manufacture consumes approximately 8.8 kwhr
per mt produced which contributes a total of 20.2 kwhr.(76)
Recovery of phosphate from the rock is usually 93-95%. Low

consumption of energy has contributed to the prominent posi-

tion of wet—process acid in fertilizer manufacture.

Thermaleprocess phosphoric acid

Thermal-process acid begins with the production of
elemental phosphorus in large electric furnaces proceeded
by oxidation and conversion of the phosphorus to phosphoric
acid. A typical facility employing three 44,000 kilowatt

furnaces requires 6,586 kwhr to produce one metric ton of

88

(75)
5.
In this example, 9.88 mt of rock containing 11% P205 was

phosphate in 85% phosphoric acid containing 54% P20

used although any quantity of rock containing about 1.08
mt P205 can be used to produce a ton of acid. Recovery
of phosphorus from the rock is generally 91-93%.

The greater power requirements of the thermal process
has resulted in low consumption of that acid in the fertilizer
industry. Production facilities are often located adjacent
to low-cost energy sources as the Tennessee Valley Authority
power plants in Tennessee and Alabama. The high quality of
elemental phosphorus from furnace operations is best suited
for industrial applications where most of the product is
marketed. One distinct advantage to furnace production of
phosphorus is that very low—grade ore may be used. Future
production of phosphorus may require greater use of thermal
installations.

Details of power consumption for both general phosphoric

acid manufacturing processes are contained in Table 11.

2.3 Triple superphosphate manufacture

Production of triple superphosphate is comprised of the
same basic processes used to produce phosphoric acid although
phosphoric acid is used in the aciduation rather than sul-
furic acid. Production follows a sequence of operations

(26) The

beginning with grinding of the phosphate rock.
rock is then reacted with acid, mixed with mechanical agita-
tors in large vats and fed into dryers. The resulting

product is granular in form which is conveyed to curing piles

 

pE\ansx o.mmmo

 

o.mw
o.mH
o.o:mo

ps\tezx o.mmH

ae\teaa m.eaa

 

m.om
m.mmH

pE\te3x m.om

cofipoesmcoo mwzoco A<BQB

msoocmaaoomfle
Azommm 0p :mv coflmso>coo

coapmpooo ooOCLBM oahpooao

ps\ae3x m.ma a as mm.m .mcaeefiam xeoa

"mmmOommld<EmmmB

coHpQEBmcoo mwpoco A¢BOE

pE\L£3x w.w © pE m.m .opsuommscme Uflom OHLBMHSm
mpHOprooao
es\aezx m.©H a pa mo.m .weflecflam soot

”mmmoommlem3

 

QMODmomm QHU< OHmOmmmomm
mo ZOE QHKBMZ mmm ZOHBmSszoo wwmmzm

HH mqm<B

90
where it remains for a period of days. The triple super—

phosphate is then shipped in bags or bulk to markets.

The production of one metric ton of triple superphos-
phate containing 46% P205 requires .65 mt of 85% phosphoric
acid containing 54% P205 and .36 mt phosphate rock contain-
ing 31.5% P205. Related energy consumption is 128.6 kwhr
per mt fertilizer, the bulk of which from fuel oil consumed
in the drying Operation.(76)

Detail of energy consumed by the production of one

metric ton of 46% P205 triple superphosphate follows:

Triple superphosphate:

 

 

rock grinding, .36 mt @ 16.5 kwhr/mt 5.9 kwhr

electricity 7.7

dryers 115.0
128.6 kwhr

2.4 Transportation and application

Transportation of fertilizer materials occurs between
raw material sources and processing centers and from manu-
facturing plants to markets. As mentioned earlier, phosphoric
acid manufacture is located near or at the site of phosphate
rock production and transportation costs are negligible.
Nearly 70% of U. S. sulfur and sulfuric acid production takes
place in Texas and the mines and acid plants located in the
coastal plain area supply the Florida industry with acid.(77)
Northern Texas sulfur production provides acid for western
states manufacture of fertilizer. The acid is transported

to Tampa by ship from Galveston and by rail from northern

Texas, near Amarillo, to the Montpelier, Idaho area. Finished

91
triple superphosphate is shipped from Tampa to New Orleans
by water and up the Mississippi River to Clinton, Iowa.
Fertilizer from the western states moves by rail to Clinton.
From Clinton, the triple superphosphate is moved by truck to
farm locations. Pertinent transportation information includ-
ing fuel consumption and equivalent energy consumption for
individual shipments is included in Table 12.

The rate of phosphatic fertilizer application is variable,
depending on soil type, moisture content, crops and other
factors. Intertilled crops like corn are generally fertilized
at the time of planting and again, later in the growing sea-
son. Close-growing crops as wheat and barley are fertilized
once at or before planting. An average of 140 liters of
fuel per hectare are consumed by tractors and similar equip—

(80) An

ment for farming operations in each growing season.
estimated 7% of consumption, or 10 liters, may be attributed
to average fertilizing operations, representing about 96.8
kwhr per hectare fertilized or 968 kwhr for a ten hectare
farm. It is assumed that average power usage given is

sufficient to apply one metric ton of 46% P205 triple super-

phosphate over one growing season.

2.5 Summary

The manufacture, transport and application of triple
superphosphate fertilizer is combined and summarized in Table
13. The majority of energy consumed in both examples is by
mining operations. Application of fertilizer is next with

about one-third of total consumption for each situation.

92

OQHHommm

 

 

**
Hose HomOHo *
Amp .mopv .mwma .moammnm Ugo mppmHEono mo xoonpcmm Amv
Amp .mopv .wcfipoocfiwcm cofipwpmommcmpe .Hmma .3 .3 .zmm AHV "oopsom
ma.mm **mm.m am.m mezzo. sooso om spoon
oadwpp Spam copcflao
mm.moH mm.HH :m.w mmzoo. aflmp moma LOQSm
. OHQfipp coucfiao poaaoapcoz
wo.mmfi om.HH mm.oa mosoo. soon: moea spoon
OHQHLB coucfiao MQEmB
mo.>m mm.HH mw.m mmqoo. Hams nmaa Uflom .Hsm Loaaoopcoz OHHHLME<
mm.ooH *mm.aa om.m wowoo. Looms mmma UHom .Hsm MQEmB copmo>amu
pE\anx Amv pE poo AHV whoowcmhe Ex mpHUoEEoo oE Eopm
H\chx UTEBmsoo ExIpE\H mo oocmpmfim
osfim> Hosm possmcoo moo:
mwposm Hosm

 

ZOHBmSszoo wwmmzm QMB<qmm Qz<
mA<HmMB<Z mmNHAHBmmm DmmmHsz Qz¢ 3<m mo Bzmzm>oz

NH mqm<e

93

 

 

 

me<mmmommmmmbm mqumB

wqmmd Qz< emomm2¢m8 «mmDBo<sz<z OB QmmHDGmm wommzm

0mm so: so 209 QHmemz mzo

ma mdm<8

o.ooa m.mmom o.ooa s.mmmm gases
w.om o.mom o.mom oo.H m.mm o.mom o.wom oo.H one<qudm<
m.: m.mma w.mmfi oo.H m.: m.::H m.::H oo.H .aomsm manage
m.m m.ama H.5m om.m H.s m.omm a.ooa om.m oeoo oasoeasm
ZOHBaBmommzeme
0.: m.me o.mmfi oo.H 0.: o.mmfi o.mma oo.H mmaeo<m22<2
.mmdpm quHme
m.a s.mma m.smfl mo.o o.a a.mma m.sma mo.o mmpeoamozsz
mHoa onomdmomd
m.: m.sHH e.mmm om.o m.m H.Hsfi m.mss om.o spoon manage
m.mm m.mooa s.mmm wo.m m.m: m.moefi m.mss mo.m oaoo oflsohomohm
20Heoaoomd moom
Hoooe sass os\shss os Hoooe seas os\shsx us
no s soaoooso do s soaoooso
mmBaEm zmmemmz aonoqm
m

94

Transportation is also significant, requiring more than 10%
of energy in both examples. The operation creating the
greatest variance between Florida and western facilities is
the production of rock. Florida rock requires greater treat-

ment and consequently consumes greater quantities of energy.

3. WASTEWATER REUSE

3.1 Reuse systems

Two basic methods are employed in application of liquid
wastes to soils, high-rate systems and low—rate systems.(8l)
Both systems apply wastewater intermittently, alternating
application with resting or drying periods. High—rate
systems apply large quantities of liquid, from a few meters
to several meters per week. Basins containing several meters
of water are preferred but furrows or large—capacity sprink-
lers can be used on land with uneven contour. Infiltration
and drying periods are usually several weeks.

Low—rate systems apply 2.5—5.0 cm per week usually
with sprinkler or spray irrigation equipment although furrows
or borders are used if the topography of the site is favor-
able. Duration of application is generally a few hours
each day or every few days. The quality of renovated waste-
water is highest with low-volume systems employing spray
or sprinkler techniques.

The majority of application systems are spray or sprink-
ler irrigation which has the greatest range of suitable soil
types and has proven effective in agricultural operations.(82)
Over 300 U. S. communities practice the use of wastewater
with some irrigation technique.

Wastewater reuse projects consist of several basic

elements. Requesite components are a source of wastewater,
95

96

storage compounds, means of conveying liquids, methods of
land application and often facilities which collect renovated
water. The flow of wastewater and processes within the sys-
tem are illustrated in Figure 17. Individual projects may
reorder the sequence of components from that shown but basic
processes required for operation will exist in most.

The operational framework of Figure 17 is representative
of a system of wastewater reuse offered for Clinton, Iowa
for comparison of fertilizer and sewage treatment plant
effluent as alternative sources of plant nutrition. Each
segment of the project will be discussed and related energy
consumption given. Findings are summarized and applied to

the example of a farm 50 km from Clinton.

3.2 Conveyance systems

Liquids are transferred by gravity flow pipelines or
by pipe under pressure, determined in part by the topography
of the land being traversed. Pressure lines employ very
large pump stations at the beginning of the line while gravity
flow is used with lift pumps at frequent intervals. Examples
of both are contained in Table 14. These data and much of
that to follow is taken from proposed treatment systems
formulated for the U. S. Army Corps of Engineers in conjunc—
tion with regional wastewater management studies done for
southeastern Michigan.(83)
The proposed Clinton, Iowa waste reuse example beings
at the point where secondary effluent is discharged from an

existing treatment facility. The liquid waste is transferred

to storage lagoons adjacent to the plant. The water is then

 

97

 

 

DOMESTIC INDUSTRIAL
WASTE ‘ , WASTE

 

 

 

 

 

 

 

SEWERAGE
SYSTEM

 

    

  

WASTE
TREATMENT

  

 

STORAGE
LAGOONS

 

CONVEYANCE
SYSTEM

 

 

      
 

LAND
APPLICATION

I

[COLLECTION OF I

 

 

 

RENOVATED WATER

 

I DISCHARGEg]

 

Figure 17. Flow of wastewater in reuse systems.

 

98

 

 

 

Amw .Mopv .poosowmcoz powwzoummz smwޣOHz campmmospsom
.mEopmmm oocmmo>coo pom psoEmeDB :oowmq .mwma .ocH chflhoosfiwcm posmm “Condom
Amcoaaow COHHHHEV hampos canso COHHHHE *
Asov AH.NHV
mom.:fi m.oam. ooa.: H :mm. m.mH ooosom .:
Aaomv Am.msv
HHo.mH s.mmm ooe.so H mmH.H m.SHH oooaom .m
ANHV A:.mv
omm.m m.mm m:m m m:o. H.mH soa>oso .m
Amv Ao.smv
moo.s o.eH :me ma mmo. :.:: aoa>oao .H
Ex\EoS\h£3x Ex\u£ a: mQOprpm Awev Amoafiev Eoummm
Houoe oesm *EoE ex come
roam nomads
saaoo
onBmzamzoo wwmmzm Qm9¢qmm 02¢
mzmemwm moz<mm>zoo Bzmqumm m>HB¢zmmeq¢ mo mmqmz<xm

:H mqmde

99

transmitted 50 km to a regional delivery point near indiv-
idual land application sites.

The southeastern Michigan locations of the systems in
Table 14 are not dissimilar to the flat plains of eastern
Iowa where Clinton is situated. Approximate averages of
8,470 and 13,940 kwhr/million cubic meters/km are taken for
gravity and pressure systems, respectively, and will be

presented in the summary.

3.3 Land application

Several techniques are employed for application of waste-
water to the soil. Spray or sprinkler irrigation is the method
receiving the greatest use in agriculture while other methods,
as furrow and border surface irrigation are less popular.

Spray Operations utilize a variety of equipment, one of which
is the fixed-set sprinkler system using a permanent under—
ground distribution network. The major advantages of a

fixed system is its adaptability to any crop or soil type,

(84)

low labor costs and low application rates. An inherent
disadvantage is the capital expense for required underground
pipelines.

A second type of spray applicator is the center—pivot
system, a self—propelled lateral supported by wheeled towers.
The rig irrigates a circular area with laterals up to 400 ‘
meters in length. The primary advantage of this method is
low cost, generally 20% of a fixed—set to irrigate the same

space. Disadvantages are higher labor costs and lack of

adaptability to irregular—shaped or uneven fields.

100

Table 15 contains energy requirements for the operation
of two center—pivot systems and a fixed-set system. The
center-pivot rig is driven by small electric motors on the
wheeled tower, consuming 10% of total requirements. The
fixed-set consumes the greatest amount of energy because of

the pressure system. These data are also represented in the

 

summary.
TABLE 15
ENERGY CONSUMPTION OF SELECTED
IRRIGATION EQUIPMENT
System kwhr/mcm*

Center-pivot
76% coverage

pump station 182,430

irrigation rigs 18,243
' 200,673

91% coverage

pump station 243,241

irrigation rigs 30,404
273,645

Fixed-set

pump station 374,416

 

1rmillion cubic meters

Source: Dow Engineering, Inc. 1972. Irrigation and Col-
lection Facilities for Southeastern Michigan Waste-
water Management Program. (ref. 85)

 

101
3.4 Collection systems

The final energy consuming component of a wastewater
reuse project is the collection of renovated wastewater.
Drainage is often required for maintenance of aerobic con-
ditions, which is determined by the characteristics of the
individual site, as poorly drained soils or a high water

table.(8u)

The tile drain also serves to collect the ren-
ovated water for further reuse or discharge to adjacent
streams. It is assumed that the hypothetical farm in Iowa
will require a collection system.

A series of gravity-flow underground laterals collect
the percolate which is lifted by low-head pumps and discharged
into open canals and directed to its final use. Power

(85)

requirements are 50,386 kwhr/million cubic meters.

3.5 Summary

The comparison of alternative systems of plant nutrition
culminates in the application of .46 mt P205 to the soil.
For fertilizer, this represents the amount of P205 contained
in one metric ton of 46% P205 triple superphosphate, which
would be applied to ten hectares of farmland, approximating
normal usage. The volume of water required to obtain the
same amount of phosphorus is variable, dependent upon the
concentration of phosphorus in the wastewater. The range
of phosphorus in treated secondary effluent is 6.7—13.0
mg P/l or 15.3—29.8 mg P205/l (Table 9). If the available
wastewater contained 6.7 mg P/l, the required volume of

water to obtain .46 mt P205 would be 30,412 cubic meters.

102
Less would be required for the upper range of 13.0 mg P/l,
or 15,516 cubic meters.

Table 16 contains components of a reuse project with
energy consumption appropriate to the volume of water re-
quired to obtain .46 mt P205, given upper and lower limits
of phosphorus concentrations. The greatest quantity of energy
consumed is in the conveyance of wastewater which is directly
proportional to the distance pumped. The lower portion of
Table 16 combines alternative systems to obtain four possible
combinations. The lowest value utilizes gravity flow of ef-
fluent with center—pivot irrigation while the highest value

uses pressure mains and a fixed—set system of irrigation.

 

2103

 

one: oo:.ea

mpouos cacao cedaaasm

 

hnzx mHH.:m coauooaaoo II pomIooxfim II Chammoum
has: HH>.=H 9:3: Nmm.mm coapooaaoo II uo>aaInoucoo II ocsmmonm
are: o:m.ma sass Hmm.mm coaoooafloo II pomIooxfim II soa>oto
has: m:m.oH sass emm.om eoaooodaoo II oo>aoIsoocoo II aoH>oto
toss was one: mmm.H agoe\snzx omm.om
onaomqqoo
one: oom.m onsx emm.HH esos\tn:x mfl:.:sm oooIooxam
ass: :HH.m sass moH.o aeoexunzx meo.oom oo>aoIaoocoo
one<onmH

Less mam.OH Less eoH.Hm eso2\snzx ooo.~mm
a ex om m ex\meoE\anzx ozmqma opsmmopm

one: m:m.o czar mmo.ma agoexonzx oom.wm:

mgmpos cacao mam.mfi
H\m0ms we m.mm

H\m we o.ma

nympoe canso ma:.om
axmoms we m.mH
axm we e.o

I as om o ex\.2oexahzx osm.m aoa>oto

moz<~m>zoo

 

m

0

m

eon .zoequo mom someomm
mmamm qaoHemmomme a 2H mme<3mem<3 2H omzH<ezoo
s so 209 onemz o:. soda: oz< wm>zoo oe ommHoomm sommzm

wH m4m<a

4. SUMMARY AND CONCLUSIONS

Phosphorus is one of the most important elements
required for life because of its relative scarcity in the
natural environment and the irreplaceable function it
serves in plant nutrition. Large localized deposits of
phosphate bearing rock are exploited to supplement soils
in agricultural production. Man's activities have removed
phosphorus from the earth, used it in a myriad of processes
and disposed of much of it to available surface waters
where recovery would require very high energy expenditures.
Man has effectively created a sub-cycle of the natural

phosphorus cycle requiring millions of years for completion.

Phosphorus consumption

 

Phosphorus has many applications in industry and
agriculture with fertilizer manufacture representing 75 to
98% of requriements for individual nations. World popula-
tion estimates for the year 2000 indicate an increase of
about 80% to approximately 6.5 billion people. Food produc-
tion facilities will be heavily taxed to provide enough food,.
even at subsistence levels. Phosphatic fertilizer is seen
as one important input for increasing the yield of agricultural
cropland.

Forecasts of phosphorus consumption for the year 2000

indicate a 500% increase in world demand while that of the
104

105
United States is expected to increase by about 400% in the

same period.

Phosphorus reserves

 

Phosphate reserves have been historically regarded as
providing an endless supply and have experienced little or
no resource conservation or planned exploitation. A 40-year
trend in U. S. mine production indicates decreasing phos-
phorus content in ore removed. United States reserves,
particularly those found in the western states, are increas-
ingly less accessible and will require greater amounts of
energy to remove and process the contained phosphate.

Schedules of depletion have been formulated based on
population growth, patterns of consumption, potential future
demand and other factors. World reserves are predicted to
endure for 105 to 505 years while United States reserves
reflect a slightly broader range of 105 to 520 years. A
plausible date of depletion is estimated to occur for both
in the latter half of the 22nd century, assuming present

patterns of consumption continue.

Phosphorus reuse and related energy consumption

 

An alternative to the use of mined and refined phosphorus
is recycling of phosphorus which has been used and disposed
of as waste. A maximum estimate of 1.9 billion metric tons
P205 representing more than 30% of P205 consumed in fertilizers
is discharged annually in the United States in municipal

and industrial wastewater.

106

Application of phosphorus in wastewater for plant nutri-
tion encounters many barriers, the most significant of which
is the large amount of energy required. Reuse projects
implemented in a period of time experiencing rapid depletion
of fossil fuel reserves and consequent scarcity will realize
abnormally high operating costs derived from the purchase
of energy.

The comparison made of alternative systems of supple- t
mental plant nutrition reflects a significant variation be- h

tween energy requirements associated with phosphatic fertil-

 

izer usage and wastewater reuse. Energy consumed by appli- X
cation of a given unit of phosphorus contained in waste— i
water was four to ten times greater than an equivalent amount
contained in manufactured fertilizer. These data, summarized
from preceeding sections, are as follows:
Fertilizer manufacture, transpor-
tation and application
Florida phosphates 3,235.7 kwhr/mt
Western states phosphates 2,625.5 kwhr/mt

Wastewater reuse
gravity flow, center-pivot system

P conc. 6.7 mgP/l 20,667 kwhr/mt

P conc. 13.0 mgP/l 10,545 kwhr/mt
Pressure flow, fixed-set system

P conc. 6.7 mgP/l 34,116 kwhr/mt

P conc. 13.0 mgP/l 17,406 kwhr/mt

Transmission of the large volume of water carrying minute
concentrations of phosphorus consumed the greatest amount
of energy. Total power requirements are influenced greatly

by the distance from the source of the wastewater to the

107

site of application and the concentration of phosphorus in

available wastewaters.

Total cost evaluation

 

This analysis has compared alternative methods of,
supplemental plant nutrition, internalizing requisite com-
ponents of each system. Evaluation has been confined to a
single input to agricultural production, albeit a very
important one, and the sources from which it may be derived.

Utilization of phosphorus contained in waste material has

 

been presented as a substitute for rapidly diminishing rock :
phosphate reserves, requiring a significantly higher expen- r
diture of energy. The unfavorable status of wastewater re-
use for obtaining phosphorus which has been shown in this
paper reflects a singular analysis of one segment of a
situation requiring more comprehensive evaluation.
Other salient factors should be considered in an en-
compassing total—cost accounting of material recycling,
including both resources and wastewater. Readily accessible
reserves of phosphate rock are undergoing rapid depletion
which will cause higher levels of energy usage to extract
and process remaining supplies. Other plant nutrients,
each requiring large amounts of energy for commercial prepara-
tion, are available for agricultural use via land application
of municipal sewage effluent. The net result of comprehen-
sive assessment of these and other contributing factors will
be to enhance the economic position of wastewater reuse.
Analyses similar to that given phosphorus are necessary for

each segment in a total—cost evaluation.

10.

LIST OF REFERENCES

Katchman, B. J. 1961. Phosphates in life processes,
pp. 1281-1343. In: J. R. VanWazer, Jr. (ed.), Phos—
phorus and its compounds. Vol. 11. Technology,
biological functions, and applications. Interscience
Publications, Inc., New York.

Sauchelli, V. 1965. Phosphates in agriculture.
Reinhold Publishing Corp., New York. 277 pp.

Hutchinson, G. E. 1952. The biogeochemistry of
phosphorus, pp. 1-35. In: L. F. Wolterink (ed.),
The biology of phosphorus. Michigan State College
Press, E. Lansing, Michigan.

Bates, R. L. 1969. Geology of the industrial rocks
and minerals. Dover Publications, New York. 459 pp.

McKelvey, V. E. 1967. Phosphate deposits. Contribu-
tions to economic geology. U. S. Department of the
Interior, U. S. Geological Survey Bulletin 1252-D.

U. S. Government Printing Office, Washington, D. C.

21 pp.

Lewis, R. W. 1970. Phosphorus, pp. 1139-1155. In:
Mineral facts and problems. U. S. Department of the
Interior. Bureau of Mines Circular 650. U. S. Govern-
ment Printing Office, Washington, D. C.

Hutchinson, G. E. 1950. The biogeochemistry of verte-
brate excretion. American Museum of Natural History
Bulletin. Vol. 96. 554 pp.

U. S. Department of the Interior. Bureau of Mines.
Minerals Yearbook - 1935 through 1971. Metals,
minerals and fuels. Vol. I & 11. U. S. Government
Printing Office, Washington, D. C.

Pevear, D. R. 1966. The estuarine formation of the
United States Atlantic Coastal Plain phosphate. Eco-
nomic Geology, 61(2): 251-255.

 

Smith, R. W. and G. I. Whitlatch. 1940. The phosphate
resources of Tennessee. Tennessee Division of Geology
Bulletin No. 48, Nashville, Tennessee. 444 pp.

108

11.

12.

13.

l4.

l5.

l6.

17.

109

U. S. Department of the Interior, Bureau of Mines,
Mineral Trade Notes. U. S. Government Printing Office,
Washington, D. C.

11:1 51(2): 44 August 1960
11:2 52(4): 40 April 1961
11:3 54(2): 44 February 1962
11:4 63(5): 41 November 1966
11:5 64(5): 26 May 1967
11:6 64(7): 31 July 1967
11:7 64(9): 37 September 1967
11:8 65(7): 12 July 1968
11:9 66(5): 28 May 1969
11:10 66(8): 21 August 1969
11:11 67(4): 24 April 1970
11:12 68(3): 29 March 1971
11:13 68(6): 15 June 1971
11:14 68(8): 37 August 1971

Pelletier, R. A. 1964. Mineral resources of south-
central Africa. Oxford University Press, Capetown.

277 pp.

McKelvey, V. E., J. B. Cathcart, Z. S. Altschuler,

R. W. Swanson and K. L. Buck. 1953. Domestic phosphate
deposits, pp. 347-376. In: W. H. Pierre and A. G.
Norman (eds.), Soil and fertilizer phosphorus in crop
nutrition. Agronomy-A Series of Monographs. American
Society of Agronomy. Vol. IV. Academic Press, Inc.,
New York.

Mansfield, G. R. 1942. Phosphate resources of Florida.
U. S. Department of the Interior. U. S. Geological
Survey Bulletin 934. U. S. Government Printing Office,
Washington, D. C. 82 pp.

Service, A. L. and C. C. Popoff. 1964. An evaluation
of the western phosphate industry and its resources
(in five parts). 1. Introductory review. U. S.
Department of the Interior, Bureau of Mines Report

of Investigations 6485. U. 8. Government Printing
Office, Washington, D. C. 86 pp.

Harre, E. A. 1971. Fertilizer trends, 1971. Tennes-
see Valley Authority. National Fertilizer Develop-
ment Center Bulletin Y-40. Muscle Shoals, Alabama.

44 pp.

Organization for Economic Co—operation and Develop-
ment. 1972. Phosphate rock and phosphatic fertilizers
in the world (role of international aid). No. 29,387,
Paris. 130 pp.

18.

19.

20.

21.

22.

23.

24.

25.

26.

27.

110

Logue, P. 1961. Utilization and economics of phos-
phorus and its components, pp. 987—1023. In: J. R.
VanWazer, Jr. (ed.), Phosphorus and its compounds.
Vol. 11. Technology, biological functions, and
applications. Interscience Publications, Inc., New
York.

United Nations, Food and Agriculture Organization.
1971. Annual Fertilizer Review, 1971. Rome.

Brown, L. R. 1970. Human food production as a process
in the biosphere. Scientific American, 223(3): 160-
170.

Swanson, R. W. 1967. Geology of the western phosphate
field, pp. 32-38. In: S. L. Groff (ed.), Proceedings
of the 1966 industrial seminar, western phosphate
region. Montana Bureau of Mines and Geology. Special
Publication No. 42. Butte, Montana.

Christenson, D. R., R. E. Lucas and E. C. Doll. 1972.
Fertilizer recommendations for Michigan. Cooperative
Extension Service Bulletin E-550. Michigan State
University, East Lansing, Michigan. 32 pp.

Phillips, A. B. and J. R. Webb. 1971. Production,
marketing, and use of phosphorus fertilizers, pp. 271-
301. In: R. A. Olson (ed.), Fertilizer technology

and usET' Soil Science Society of America, Inc.,
Madison, Wisconsin.

Sauchelli, V. 1960. Normal superphosphate: chemistry
and technology, pp. 129-166. In: V. Sauchelli (ed.),
Chemistry and technology of fertilizers. American
Chemical Society Monograph Series, No. 148. Reinhold
Publishing Corp., New York.

Rogers, H. T., R. W. Pearson and L. E. Ensminger.
1953. Comparative efficiency of various phosphate
fertilizers, pp. 189-242. In: W. H. Pierre and A. G.
Norman (eds.), Soil and fertilizer phosphorus in crop
nutrition. Agronomy-A Series of Monographs. American
Society of Agronomy, Vol. IV. Academic Press, Inc.,
New York.

Payne, J. H., Jr. 1961. Fertilizer manufacture,

pp. 1071—1148. In: J. R. VanWazer, Jr. (ed.), Phos-
phorus and its compounds. Vol. 11. Technology,
biological functions, and applications. Interscience
Publications, Inc., New York.

Pesek, J., G. Stanford, and N. L. Case. 1971.
Nitrogen production and use, pp. 217-270. In: R. A.
Olson (ed.), Fertilizer technology and use. Soil
Science Society of America, Inc., Madison, Wisconsin.

 

28.

29.

30.

31.

32.

33.

34.

35.

36.

37.

38.

39.

111

Slack, A. V. 1968. Fertilizer developments and trends.
Noyes Development Corp., Park Ridge, New Jersey. 405 pp.

United Nations, Department of Economic and Social
Affairs. 1973. World population prospects assessed
in 1968. Population studies No. 53, New York.

United Nations, Office of Public Information. 1962.
Population and food supply. Freedom from Hunger Cam—
paign. Basic Study No. 7, New York.

Ehrlich, P. R. and J. P. Holden. 1969. Population and
panaceas, a technological perspective. Bioscience,
19(12): 1065-1071.

 

Committee on Resources and Man. 1969. Resources and
man. National Academy of Sciences, National Research
Council. W. H. Freeman and Co., San Francisco. 259 pp.

Organization for Economic Co-operation and Develop-
ment. 1967. The food problem of developing countries.
No. 23,479, Paris. 114 pp.

Anonymous. 1973. The Australian phosphate fertilizer
industry. Phosphorus and Potassium. The British
Sulfur Corp., Ltd., London. N0. 65. pp. 29-35.

Fischman, L. L. and H. H. Landsberg. 1972. Adequacy
of nonfuel minerals and forest resources, pp. 77-101.
In: Population, resources, and the environment. U. S.
Commission on Population Growth and the American
Future, Commission Research Reports, Vol. III. U. S.
Government Printing Office, Washington, D. C.

Mansfield, G. R. 1942. Phosphate deposits of the world.
Industrial and Engineering Chemistry, 34(1): 9-12.

 

Jacob, K. D. 1953. Phosphate resources and processing
facilities, pp. 117-166. In: K. D. Jacob (ed.),
Fertilizer technology and resources in the United
States. Agronomy—A Series of Monographs.. American
Society of Agronomy, Vol. III. Academic Press, Inc.,
New York.

Landsberg, H. H., L. L. Fischman and J. L. Fisher.
1963. Resources in America's future, patterns of
requirements and availabilities, 1960-2000. Resources
of the Fugure, Inc. The John Hopkins Press, Baltimore.

1917 DP-

VanWazer, J. R., Jr. 1961. Occurrence and mining, pp.
955-986. In: J. R. VanWazer, Jr. (ed.), Phosphorus

and its compounds, Vol. 11, Technology, biological
functions, and applications. Interscience Publications,
Inc., New York.

 

40.

41.

42.

43.

44.

45.

46.

47.

48.

49.

112

Anonymous. 1971. Report on global ecological problems.
BulIetin of the Ecological Society of America, 52(4):
9-1 .

Legal, C. C. and O. D. Myrick, Jr. 1968. History and
status of phosphoric acid, pp. 1-90. In: A. V.

Slack (ed.), Phosphoric acid. Fertilizer Science and
Technology Series, Vol. I, Part 1. Marcel Dekker, Inc.,
New York.

Mero, J. L. 1960. Minerals on the ocean floor.
Scientific American, 203(6): 64-72.

 

Maxwell, A. E., K. O. Emery and B. H. Ketchum. 1968.
Ocean science and marine resources, pp. 17-68. In;
E. A. Gullian (ed.), Uses of the seas. The American
Assembly. Columbia University, Prentice-Hall, Inc.,
Englewood Cliffs, New Jersey.

Bell, L. V. 1967. A history of the western phosphate
industry, pp. 2-9. In: S. L. Groff (ed.), Proceedings
of the 1966 industriEI seminar, western phosphate region.
Montana Bureau of Mines and Geology, Special Publication
No. 42, Butte, Montana.

Bahr, T. G., R. A. Cole and H. K. Stevens. 1972.
Recycling and ecosystem response to water manipulation.
Institute of Water Research Technical Report No. 37,
Miihigan State University, East Lansing, Michigan.

12 pp.

Ferguson, F. A. 1968. A nonmyopic approach to the
problem of excess algal growth. Environmental
Science and Technology, 2(3): 188-193.

 

 

 

American Chemical Society. Subcommittee on Environ-
mental Improvement. 1969. Cleaning our environment,
the Chemical basis for action. Washington, D. C. 249

pp.

Kramer, J. R., S. E. Herbes and H. E. Allen. 1972.
Phosphorus: Analysis of water, biomass, and sediment,
pp. 51-100. In: H. E. Allen and J. R. Kramer (eds.),
Nutrients in natural waters. Environmental Science

and Technology Series, Wiley-Interscience Publications,
New York.

Ketelle, M. J. and P. D. Uttormark. 1971. Problem
lakes in the United States. Water Resources Center.
Technical Report No. 16010 EHR, University of Wiscon-
sin, Madison, Wisconsin.

 

50.

51.

52.

53.

54.

55.

56.

57.

58.

59.

60.

113

Grundy, R. D. 1971. Strategies for control of man-
made eutrophication. Environmental Science and
Technology, 5(12): 1184-1190.

 

 

SOpper, W. E. and L. T. Kardos. 1973. Vegetation
responses to irrigation with treated municipal waste—
water, pp. 271—294. In: W. E. Sopper and L. T. Kardos
(eds.), Recycling treated municipal wastewater through
forest and cropland. Pennsylvania State University
Press, University Park, Pennsylvania.

Muskegon County Board. 1969. Muskegon County plan
for managing wastewater. Muskegon County Metropolitan
Planning Commission, Muskegon, Michigan.

Pound, C. E. and R. W. Crites. 1973. Characteristics
of municipal effluents, pp. 49-62. In: Proceedings of
the Joint Conference on Recycling Sludge and Effluents I
on Land, July 9-13, 1973. Champaign, Illinois, National
Association of State Universities and Land-Grant
Colleges, Washington, D. C.

 

U. S. Department of the Interior. Federal Water Pollu—
tion Control Administration. 1968. The Cost of Clean
Water, Vol. 1., Summary Report. U. S. Government
Printing Office, Washington, D. C. 39 pp.

Todd, D. K. (ed.) 1970. The water encyclopedia.
Water Information Center, The Maple Press Co., Port
Washington, New York. 559 pp.

Vollenweider, R. A. 1968. Scientific fundamentals

of the eutrophication of lakes and flowing waters,

with particular reference to nitrogen and phosphorus

as factors in eutrophication. Organization for Economic
Co-operation and Development. Directorate for Scientific
Affairs, No. 66,748, Paris.

Nesbitt, J. B. 1973. Cost of spray irrigation for
wastewater renovation, pp. 334-338. In: W. E. Sopper
and L. T. Kardos (eds.), Recycling trEEted municipal
wastewater through forest and cropland. Pennsylvania
State University Press, University Park, Pennsylvania.

Train, R. E., J. A. Busterud and B. E. Willard. 1973.
Energy and the environment. Council on Environmental
Quality. U. S. Government Printing Office, Washington,

D. C. 58 pp.

Hammond, A. L. 1972. Energy options: Challenge for
the future. Science, 177: 875—876.

U. S. Department of Agriculture. 1967. Fertilizer use
in the United States by crops and areas. Agriculture
Research Service Statistical Bulletin No. 408. U. S.
Government Printing Office, Washington, D. C.

61.

62.

63.

64.

65.

66.

67.

68.

69.

114

Ruhlman, E. R. 1958. Phosphate rock (in two parts).

Part 1. Mining, beneficiation, and marketing. U. S.

Department of the Interior. Bureau of Mines Informa-

tion Circular 7814. U. S. Government Printing Office,
Washington, D. C. 33 pp.

Spencer, R. N. 1971. Multiple zone mining plus
beneficiation of western phosphate rock. U. S. Depart—
ment of the Interior. Bureau of Mines Report of Inves-
tigation 7512. U. S. Government Printing Office,
Washington, D. C. 18 pp.

LeBaron, I. M. 1960. Phosphate rock, mining, washing,
and beneficiation, pp. 68-85. In: V. Sauchelli (ed.)
Chemistry and technology of fertilizers. American
Chemical Society Monograph Series, No. 148. Reinhold
Publishing Corp., New York.

Rumfelt, H. 1968. Excavation and loading, cyclical
methods - shovels and backhoes, pp. 427-444. In:

E. P. Pfleider (ed.), Surface mining. American Institute
of Mining, Metallurgical, and Petroleum Engineers,

Inc., New York.

Scott, S. A. and T. R. Young. 1968. Hydraulic trans-
portation, pp. 622-636. In: E. P. Pfleider (ed.),
Surface mining. American Institute of Mining, Metallur-
gical, and Petroleum Engineers, Inc., New York.

VanKleunen, J. P. 1968. Belt Conveyors, pp. 589-609.
In: E. P. Pfleider (ed.), Surface mining. American
Institute of Mining, Metallurgical, and Petroleum
Engineers, Inc., New York.

Wideman, F. L. 1958. Mining inclined beds of phos-
phate rock, San Francisco Chemical Co. mines, Rich
County, Utah. U. S. Department of the Interior.
Bureau of Mines Information Circular 7849. U. S.
Government Printing Office, Washington, D. C. 27 pp.

Jackson, C. F. and J. H. Hedges. 1939. Metal-mining
practices. U. S. Department of the Interior. Bureau
of Mines Bulletin 419. U. S. Government Printing
Office, Washington, D. C. 512 pp.

McWilliams, J. R. and E. G. Erickson. 1959. Methods
and costs of shaft sinking in the Coeur D'Alene Disa
trict, Shoshone County, Idaho. Department of the
Interior. Bureau of Mines Information Circular 7961.
U. S. Government Printing Office, Washington, D. C.

49 pp-

70.

71.

72.

73.

74.

75.

76.

77.

78.

115

Olds, E. B. and E. W. Parsons. 1957. Methods and
costs of deepening the Crescent Shaft, Bunker Hill and
Sullivan Mining and Concentrating Company, Kellogg,
Shoshone County, Idaho. U. S. Department of the
Interior. Bureau of Mines Information Circular 7783.
U. S. Government Printing Office, Washington, D. C.

19 pp.

Bolmer, R. L. 1962. Sinking methods and costs fOr a
small vertical shaft with steel supports: Keystone Mine,
Crested Butte, Colorado. U. S. Department of the
Interior. Bureau of Mines Information Circular 8086.

U. S. Government Printing Office, Washington, D. C.

25 pp.

Howes, M. H. 1962. Methods and costs of shaft sinking,
U. S. Atomic Energy Commission Project Gnome, near
Carlsbad, N. Mex. U. S. Department of the Interior.
Bureau of Mines Information Circular 8195. U. S.
Government Printing Office, Washington, D. C. 49 pp.

Falkie, T. V. 1969. A survey of current open pit
practices in Florida phosphate, pp. 248—257. In;

H. L. Hartman (ed.), Case studies of surface mining.
The American Institute of Mining, Metallurgical, and
Petroleum Engineers, Inc., New York.

Waggaman, W. H. and V. Sauchelli. 1952. Superphosphate,
its manufacture and properties, pp. 238-289. In; W. H.
Waggaman (ed.), Phosphoric acid, phosphates and phos-
phatic fertilizers. American Chemical Society Mono-
graph Series, No. 34. Reinhold Publishing Corp., New
York.

Waggaman, W. H. 1952. Comparison of sulfuric acid

and thermal reduction processes for manufacturing
phosphoric acid, pp. 210—225. In: W. H. Waggaman (ed.),
Phosphoric acid, phosphates and phosphatic fertilizers.
American Chemical Society Monograph Series, No. 34.
Reinhold Publishing Corp., New York.

Bixby, D. W., R. L. Rucker and S. L. Tisdale. 1966.
Phosphatic fertilizers, properties and processes.
Technical Bulletin No. 8. The Sulfur Institute, Wash-
ington, D. C. 89 pp.

Ellison, S. P. Sulfur in Texas. 1971. The University
of Texas. Bureau of Economic Geology, Handbook No. 2.
Austin, Texas. 48 pp.

Hay, W. W. 1961. An introduction to transportation
engineering. John Wiley and Sons, Inc., New York.

505 pp.

 

79.

80.

81.

82.

83.

84.

85.

116

Handbook of Chemistry and Physics. 1972. The Chemical
Rubber Publishing Co., Cleveland, Ohio.

De Graff, H. F. and W. E. Washbon. 1943. Farm-tractor
fuel requirements. New York Agricultural College
(Cornell) Bulletin No. AE449. Ithaca, New York. 4 pp.

Bouwer, H. 1973. Land treatment of liquid waste:

the hydrologic system. pp. 103-111. In: Proceedings
of the Joint Conference on Recycling Sludge and Ef-
fluents on Land, July 9—13, 1973. Champaign, Illinois,
National Association of State Universities and Land-
Grant Colleges, Washington, D. C.

Pound, C. E. and R. W. Crites. 1973. Wastewater
treatment and reuse by land application. Volume I -
Summary. Office of Research and Development. ‘U. S.
Environmental Protection Agency. U. S. Government
Printing Office, Washington, D. C. 80 pp.

Bauer Engineering, Inc. 1972. Lagoon treatment and
conveyance systems, southeastern Michigan wastewater
management. Final report. Detroit District, U. S.
Army Corps of Engineers. 174 pp.

Dow Engineering, Inc. 1973. Wastewater irrigation
using privately owned farmland in southeastern Michigan.
Phase IV Report. Detroit District U. S. Army Corps of
Engineers. 84 pp.

Dow Engineering , Inc. 1972. Irrigation and collection
facilities for southeastern Michigan wastewater manage-
ment program. Detroit District U. S. Army Corps of
Engineers. 195 pp.

 

N STATE UNIVERSITY LIBRARIES

lllll ||le|||| Illlll

M1111
. 31293 3062 2918