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THE TREATMENT OF CYANIDE
WASTE WITH LIME-SULPHUR
TO DESTROY ITS TOXICITY

Thesis for tho Degree of B. S.
MICHIGAN STATE COLLEGE

DaIe W. Granger
I94I

I"I"! E815

’-

 

THE TREATIEEN T
of
CYANIDE WASTE
with
LIME - SULPHUR
to

DESTROY ITS TOXICITY

A THESIS

Submitted to the

Faculty of

MICHIGAN STATE COLLEGE

Dale W. Granger
0‘.”

Candidate for degree of

Bachelor of Science

June 1941

TH 5:515

C {:10 " /

b’

ACKNOWLEDGMENT

The writer wishes to acknowledge his appreciation to

Mr. E. F. Eldridge for his thoughtful sugwestions and helpful

0

assistance in this study.

13609-1

COHTFNTS

Statement of the Problem

Survey of the Literature
The Toxic Action of Cyanides
DiSposal ty Dilution
Pending of the Waste
Reactions of Cyanides

Acid Treatment

"U

otassium Permenganate Treatment

Experimental Work
Determination of Cyanides in Water

Fish Test Treeted with Cyanide Solution

Interpretation of Results

Summary of EXperimental Results and Conclusions

References

C)!

11

15

17

STATEMENT OF THE PROBLEM

The primary objective of this study is to determine
the feasibility of the use of lime~sulphur in the treatment
of cyanide waste to destroy the toxicity or lethal effect of
this industrial sewage as it presents itself in the manufac—
ture of case hardened steels and in electro-plating processes.
It is the writer's belief that a more satisfactory
method of treatment of this waste can be found. The present
methods of treatment present problems which constitute a hazard

either to the safety of individuals or from some other standpoint.
SURVEY OF THE LITERATURE

Various salts of cyanide, chiefly sodium and potassium,
are used in the electro-plating industries for the plating of
copper, zinc, nickle, chromium and other metals. The washings
from these plated parts manufactured for every day needs con-
tain cyanides in varying concentrations and, hence, create a
problem of disposal in a safe and satisfactory manner.

Cyanides are very poisonous and when discharged into
streams as a method of disposal create a menace not only to
fish and other aquatic life, but to cattle and other animals
which may frequent the stream. Also there is always the pos-
sibility of humans' coming in contact with a stream so polluted.

The Toxic Action of Cyanides
The toxic action of the cyanides is exerted physiologically

to reduce or entirely eliminate the utilization of oxygen.(l)

This may be presented better by observing Proiessor Andrews
Karsten's, of South Dakota State School of Mines, experiments

(2)

on the effects of cyanide on trout. He states that he believes
the action of the cyanide was through the blood by the formation
of cyano-hemoglobin and points out that perhaps the hemoglobin
has a marked affinity for cyanide. Hence, the blood carried
cyanide rather than oxygen to parts of the body which require
oxygen. He observed that fish killed by cyanide had extremely
red gills.
$5)

Medical handbooks bea out his theory. The central nervous
system is first stimulated and then depressed and finally paralyzed.
The stimulation is especially marked in the medulla, so that the
respiratory center, vasomotor, vagal centers are stimulated, re—
sulting in an acceleration of the respiration, constriction of
the blood vessels, and slowing of the heart. The blood pressure
rises on account of vasoconstriction in Spite of the slowing of
the heart, but soon falls on account of vasodilation. The respira—
tions are at first accelerated as stated before, but soon become
slowed and shallow. Coma follows quickly, sometimes preceded by
convulsions; death being due to aSphyxia. Hydrocyanic acid enters
the blood very rapidly and, while in the circulation, profoundly
affects metabolism so that the tissues lose their power of absorb~
ing oxygen. Contrary to previous belief it does not fix oxygen
more firmly to the hemoglobin, but forms cyanohemoglobin which dif-
fers from ordinary hemoglobin in its bright red color, and which is
responsible for the bright red color of the blood.

4
M. M. Ellis( hf the United States Department of Commerce,

N3

Bureau of Fisheries, reported in his work that

l. Ammonium ferrocyanide of 150-?00 p.p.m. killed

orange Spotted sunfish in one hour.

2. Ammonium thiocyanate 200 p.p.m. was lethal to

fish.

5. Potassium cyanide of 0.1 to 0.5 p.p.m. in hard

water killed gold fish in 5-4 days.

4. Potassium ferricyanide of 9000 p.p.m. was not

lethal to minnows and gold fish.

5. Potassium ferrocyanide of 2000 p.p.m. was not

lethal to minnows and gold fish.

Washings from plating rooms will vary as to the type of
plating process and as to the management of he plant, but in
general they will run between 500-500 p.p.m. of cyanide. Care
should be taken that no vats are dumped during the process of
cleaning, but rather that the contents should be transferred to
another vat or tank. With good cooperation of the employees
there is no reason why concentrated cyanide should enter any

sewer or stream.

Disposal by Dilu io

 

Present methods of diSposal of cyanide waste are, in the
writer's opinion, none too satisfactory. Dilution by discharge

Ureat care

0

into streams is an easy method of diSposal, however,
should be taken that the dilution is sufficient to reduce the
cyanide content below that lethal to fish and other aquatic life.
For average plating room waste this-should be about one part in

two to three million. Care should be taken to introduce the waste

")4

evenly over the stream so that areas of high concentration of
cyanide do not pass down stream. At best this is a poor method
of diSposal and should be resorted to only in cases of accident
when no other method can be used.

Ponding_of the Waste

 

Ponding the waste is a frequent practice of many factories.
The ponds are made by throwing up an earth dyke about an area of
land forming a retention basis for the waste. It is good practice
to fence these ponds in and put up warning signs to the public.
The use of ponds is unsatisfactory in that wells in the vicinity
may become contaminated by seepage or children may come in direct
contact with the waste. The cyanide content of waste treated in
this manner will entirely disappear over a period of time if no
new waste is added. Several factors effect the rate of reduction
of the cyanide. Rain or dilation, seepage, temperature and chemi-
cal action with the elements all tend to aid this cause. No def-
inite time limit can be placed as to complete removal of the toxic
substances since the above mentioned factors all enter into the
destruction of the cyanide. Before a pond of waste is drained,
selected samples should be collected and tested for cyanide.
While this method of treatment is rated as a better means of
cyanide waste disposal than discharge direct to the stream, it is
none too good and should be resorted to only in case other methods
are not available.

Reactions of annides

 

Listed below are some reactions of the cyanides and perhaps

1
explain the elimination of cyanides by ponding.( )

U1

An aqueous solution of the cyanides is unstable and
hydrolysis takes place with the production of ammonia, thus:
KCN + H20 -—9 HCOOK + NH5
The cyanides are oxidized by ox*gen of the air and
cyanates are produced. These in turn are hydrolized in water
solution to produce ammonia and an acid carbonate.
KOCN + H20 ——-> N115 + KHCOS
The cyanides are decomposed by carbon dioxide with the
production of HCN a soluble and volatile gas which is gradually
evolved in air.
KCN + H2005 ——9 HCN + KHCOS
Acid Treatment
Two recent methods developed in the last ten years have
proved quite successful in the destruction and removal of the
cyanide in plating room waste.
When cyanides come in contact with acids, hydrogen cyanide
or hydrocyamic acid is formed which is extremely volatile and
can be removed from the waste by bubbling air through the waste.
The success of the treatment depends on the acid concentration
required, the period of aeration, the completeness of cyanide re—'
moval and the toxicity of the remaining waste.
In this process the plating room wastes are collected in
an acid resisting tank and the correct amount of sulphuric acid
in excess of 10% based on the p.p.m. potassium cyanide and alkals
inity of solution is added. The contents of the tank are aerated
for ten to sixteen hours, depending on the concentration of potas-
sium cyanide, to remove the hydrocyanic acid gas. Important

factors to watch in this treatment as observed by E. F. Eldridge(l)

are as follows:

1.

In calculating the correct amount of acid to use for
neutralizing the potassium cyanide, the natural alkal-
inity of the water must be neutralized. Hence a test
to determine the alkalinity in terms of calcium carbon-
ate must be run and the necessary amount of sulphuric
acid to react with it is calculated and added to amount

ecessary for the potassium cyanide treatment.

{:3

t‘rj

xperiments have shown that 10? more acid should be

used than is theoretically needed in the reaction to
obtain best results.

The pH of the solution during treatment should never

be higher than between 5 and 6 and may be lower for
complete removal of the cyanides.

About 7.5 cubic feet of air is required per gallon of
waste treated and should be admitted to solution through
diffuser plates placed in bottom of the tank. They
should have an area of about one quarter of the area of
the tank.

A stack of not less than 40 feet in height and an aha-
tight hood should be attached to the tOp of the tank
through which a forced air fan blows the hydrocyanic
acid gas into the air. The gas is very toxic to humans
and utmost care should be observed at all times to handle
this method of treatment in a safe way. It is this
reason alone (safety) that marks this type of treatment

as being not too satisfactory.

Potassium Permrnganate Treatment

Oxidation of the cyanides with potassium permanganate(l)
is the other method of more recent tree ment. This reaction
will occur in either a neutral or alkaline solution and is as
follows:

EKCN + 2‘KI'JnO4 + 31-120 .9 21‘3n(OH)4 + EKOCN
Sufficient time must be alloted for the complete reaction to
take place; usually tvelve to sixteen hours are necessary.
By equation 1.62 parts by weight of KMnO4 are required to
exactly oxidize the one part of KCN or its ecuivalent.

In this process, as in the latter, the wastes are drawn
to a holding tank which should be equipped with a sludge hopper
and drawn—off valve. They are treated with the calculated
quantity of KMnO4. Thorough mixing for about thirty minutes
by use of diffused air plates followed with a settling period
of fifteen hours completes the treatment. At the end of this
period the clear supernatant liquid should be diluted one to
one and then may be drained to the sewer or to the stream. The
sludge, although not toxic in concentrations between 600 to
1000 p.p.m., will kill fish above that. Hence it probably would
be best to build a small sludge drying bed for sludge diSposal
althOUgh Small amounts of the sludge added to a stream with a
liberal flow would probably not cause any trouble.

A study on the treatment of 10,000 gallons of cyanide waste
of 100 p.p.m. was made to determine the cost of the above methods.
Using the acid treatment, the cost was $2.04, and using KHnO4,

the cost was $2.15. This included treatment of the alkalinity

of the water and aerating cost.
1 .
A further study by Eldridge( )proved conclus1vely that

the addition of cyanide to sewage sludge greatl inhibits its

4

\

digestion, hence eliminating the possible use of municipal
sewage treatment plants as a satisfactory method of diaposal

of cyanide waste.

EXPFRTHTN'AL YORK

The aim of this work vas to determine whether or not
if potassium cyanide were treated eith a solution of line-
sulphur the toxic effects of the cyanide would be destroyed.
Potassium cyanide, used, was obtained from the Olds
Motor Works and contained 93% KCN by analysis. The commercial

lime-sulphur purchased from Carrier-Stephens Chemical Co.

showed an analysis as follows:

CU

aume - ”20 at 1500.

Calcium thiosulohate - 1.5%

:0.“
(3/0

Water and other inert ingredients ~ 88.
Lime and sulphur in solution - 81.5%
One of the first problems presenting itself in this work
was the method of testing or checking the results f treatment.
The first method used was a colorimetric test as follows:
Determination of Cyanides in Vater
Solutions:
(1) Acetone containing 4 grams of free sulphur per 100 cc.

(2) Concentrated nitric acid.

(5) Ferric nitrate solution concsining 5 grevs ferric
nitrate per 100 cc.

(4) Permenent color standards from potassium chlorOpletin—
ate (a) and cobaltus chlorid (b).

(a) Dissolve 0.4 ‘rem of potessium chloroplstinete in
a smell amount of water, add ?0 cc concentrated 101 and dilute
to exectly 100 cc with distilled water.

(b) Dissolve 4.8 greus cobaltus chloride (CCCl .GH 0)
in a Smell amount of distilled water, add ?0 cc of concentrated
HCl and make up to exactly 100 CC.

Add the erect amounts of (e) and (b) as given in the fol-

lowing table to 100cc. Nessler tubes end meke up to the Kerk.

ON (a) (b)
p.p.m. cc cc
0.5 4.5 1.0
1.0 6.0 1.6
2.0 12.5 5.8
5.0 15.2 6.0
4.0 ?4.5 10.0
5.0 58.0 12.5
Procedure:

(1) To about 110 cc of the sample to be tested in a beaker
add 20c of the acetone and sulphur mixture. (Be sure to shake
the mixture thoroughly so that the sulfur is well mixed with the
acetone before adding it to the sample. Then add it quickly
before the sulfur has time to settle.)

(9) Heat the solution to boiling. Boil gently until cloudi-
ness disappears. Should the cloudiness reappear upon cooling,

heat until it does disappear permanently.

(5) When cool, add 1 cc of concentrated nitric acid and
5 cc of ferric nitrate solution.
(4) Filter into a Nessler tube to the 100 cc mark and

1

compare the color with the permanent standards prepared above.

0‘)

This test failed to check results because it depenr upon
the combination of the free sulphur with KCN to form potassium
thiocyanate. Upon addition of Fe(N05)3, it forms ferric thio-
cyanate which gives the characteristic red color. However, in
the treatment with lime—sulphur this reaction has already taken
place and the red coloration is obtained even though no cyanide
as such is present.

The standard silver nitrate test was next attempted. Com-
plete procedure for this test may be found on page 14 of "Analysis
of Water and Sewage" by Theroux, Eldridge and Mallmann. This
test is given for chlorides but may be used for cyanides as well.
The test also failed because a silver sulphide precipitate is
formed from the excess lime-sulphur and interferes with the test.

Since chemical tests cannot be used, it was decided at
this time to use goldfish as a check on the treatment by placing
them in treated solutions to determine if the toxicity had been
destroyed. All tests completed in the laboratory were checked

by gold fish and the table which follows shows the collected

data:

TABLE NO. 1

Fish Test with Treated Cyanide Solution

11

 

 

 

 

 

 

 

No. of Concentration c.c. Dilution Amount Time of fish
Test of KCN used of used to die
Lime—sulphur in minutes
1 - - - - .01 of 1% 100000 57
2 — - - - .01 of 1% 100000 1495
5 10.2 p.p.m. 100000 none none Died during night
4 10.2 p.p.m. 100000 '.01 of 1% 2500 " " "
5 10 2 p.p.m. 100000 .01 of 1% 50cc 1500, apparently OK
6 10.2 p.p.m. 100000 .01 of 1% 5000 Died after 24 hrs.
7 10.2 p.p m. 100000 .01 of 1% 15000 Died after 48 hrs.
8 100.0 p.p.m. 100000 .1 of 1% none 45
9 100.0 p.p.m. 100000 .1 of 1% 2500 80
10 100.0 p.p.m. 100000 .1 of 1% 5000 90
11 100.0 p.p.m. 100000_ .1 of 1% 7500 105
12 100.0 p.p.m. 100000 .1 of 1% none 90
15 100.0 p.p.m. 100000 .1 of 1% - — 110
14 100.0 p.p.m. 100000 .1 of 1% - — 115
15 100.0 p.p.m. 100000 .1 of 1% 7500 65
16 100.0 p.p.m. 100000 .1 of 1% 10000 65
17 100.0 p.p.m. 100000 .1 of 1% 12500 65
18 100.0 p.p.m. 100000 .1 of 1% 15000 65
19 100.0 p.p.m. 100000 ..01 of 1% 5000 20
20 100.0 p.p.m. 100000 .01 of 1% 10000 15
21 100.0 p.p.m. 100000 .01 of 1% 15000 15

 

 

 

 

 

 

solution to determine if it were toxic itself to fish life.

L
‘1

J
I

_:_ri
T

Test number one was a blank test run on a .01% of lime—sulphur

The dilu-

tion was made from distilled water because tap water causes precipita-

tion of sulphur.

This gold fish lived 57 minutes in this solution,

however, death was undoubtedly due to lack of diss01Ved oxygen in

the solution. Test number two follows exactly the same steps as number

one except that the solution was aerated.

In this solution the

12

gold fish lived 25 hours with no ill effects. Temperatures of
the aquarium and lime-sulphur solution were checked and found
to be 660F and 65°F, respectively. This was done to prevent
any shock to the gold fish upon being transferred from one

solution to another. At the end of this test a very fine 1i ht—

colored, brownish precipitate had formed. A small amount col—

lected in a test tube and treated with standard Silver nitrate

ne that some

.3

1J0

gave a heavy brownish black precipitate indicat

‘ 0

form of a sulphide had been produced, possibly calcium sulphide.
Tests numbers 5, 4, and 5 were run as follows: Test
number 5 contained one liter of 10.2 p.p.m. of KCN. No lime—
sulphur solution was added. The solution was aerated from the
beginning of the eXperiment (10:00 a.m.) for five hours. The
gold fish was apparently in good shape at 6:00 p.m.; however,
it died during the night. Test number 4 contained one liter of
10.2 p.p.m. of KCN and was treated with 2500 of 0.01% lime-
sulphur solution. Air was likewise bubbled through this solu-
tion for five hours. The gold fish also was in apparent good
health at 6:00 p.m. but died during the night. Test number 5
contained one liter of 10.2 p.p.m. KCN and was treated with
5000 of 0.01% lime-sulphur solution. This mixture was aerated
for five hours as in tests 5 and 4. This gold fish lived for
25 hours or 1500 minutes and exhibited no ill effects from the
treatment, hence was assumed to be in good health. H wever,
24 hours later this gold fish which had been p aced in frssl

aerated tap water was dead.

It may be well to explain here that all solutions of

both lime-sulphur and potassium cyanide were made from distilled
water. Aeration employed was for the purpose of building up
the dissolved oxygen supply in the solution.

Tests numbers 6 and 7 were run to check the results found
in number 5. Test number 6 contained one liter of 10.2 p.p.m.
KCN and 5000 of lime-sulphur solution. The gold fish in this
solution died between 56 and 48 hours after start of the treat-
ment. Aeration was continuous. Test number 7 contained one
liter of 10.2 p.p.m. KCN and 150 cc of .01 of 1% lime-sulphur

solution and was continuously aerated. The gold fish lived

J

icated

5‘

in this solution between 48 and 60 hours. This check int
possibilities of treatment even though the fish had died, perhaps
due to some other outside factor which was not under control.

With this thought in mind from past results a further
check was desirous. Hence, new solutions of potassium cyanide
were made up of l00 p.p.m. concentration. It was believed that
since the KCN concentration had been made ten times stronger
that likewise the concentration of the lime-sulphur solution
should be increased to 0.1%.

Test number 8 contained one liter of 100 p.p.m. 0N sol—
ution and was run as a blank. The gold fish lived 45 minutes.
Test number 9 contained one liter of 100 p.p.m. K01 and 2500
of 0.1 of 1% lime—sulphur solution. The gold fish lived 80 min.
in this solution. Test number 10 contained one liter of 100 p.p.m.
KCN and 500C of 0.1 of 1% lime—sulphur solution. The gold fish
lived 90 minutes in this solution. Test number 11 contained one

liter 100 p.p.m. KCN and 75 cc of 0.1 of 1% lime—sulphur solution

14

The gold fish lived 105 minutes in this solution. The last four
fish, 8, 9, 10 and 11 were all aerated continuously until the
fish had died. Although the fish lived over an hour in these
solutions as treated, they all exhibited very marked evidences

of the toxicity of the solution. About one-half hour after being
placed in these treated synthetic wastes, the gold fish raced
around in the tank, coming to the surface, often gulping air and
even jumping from the water. They seemed to lack a sense of bal~
ance and were often observed swimming on their sides or back. In
about 15 or 20 minutes more the fish had quieted down considerably,
becoming very lackadaisical. The fish seemed to lack strength to.
swim and often sank to the bottom. The gills became very red and
a reddish band had develOped completely around the body of the
gold fish at the point where the gills are attached to the body.

Tests number 12, 15 and 14 were run with the previous
solutions used in tests number 9, 10, and 11. No additional
treatment was used except to aerate the solution continuously.
These three experiments were run to check the possibilities of a
delayed effect of treatment. Results from these tests were as
follows: The fish in test 12 died in 90 minutes, in number 15,
110 minutes and in number 14, 115 minutes. This seems to prove
beyond any doubt that there was no delayed action.

To check further with these higher concentrations of both
potassium cyanide and lime-sulphur solutions, a series of four
more tests were run with increased amounts of lime-sulphur
solution of 0.1% added. Test number 15 contained one liter of
100 p.p.m. KCN and 75cc of 0.1% lime-sulphur solution. Test

number 16 contained one liter of 100 p.p.m. KCN and 100 cc of

15

0.1% lime—sulphur solution. Test number 17 contained one liter

of 100 p.p.m. KCN and 125cc of 0.1% lime-sulphur solution. Test
number 18 contained one liter of 100 p.p.m. of KCN and 150 cc of
0.1% lime-sulphur. All solutions were aerated continuously until
the death of the gold fish. All the fish died within 65 minutes
after starting the experiment. In this series of tests, as before,
the gold fish acted very excited and swam about considerably, and
then after a few minutes became very quiet with the characteristic

deep red colored gills. In these increased doses of lime-sulphur,

the treated mixture of potassium cyanide became quite cloudy and
seemed to contain a very fine colloidal precipitate. This may
have aided in bringing the life of the gold fish to a more rapid
end, as this fine material could possibly have clogged the gills.

A final set of three tests was made with a higher dilution
of lime—sulphur. Test number 19 was prepared by mixing one liter
of 100 p.p.m. of KCN and 50cc of .01% lime-sulphur together.
The solution was aerated continuously. The gold fish lived in
this solution 20 minutes. Test number 20 was prepared by mixing
one liter of 100 p.p.m. KCN with 100 cc of .01% lime-sulphur
solution. The solution was aerated continuously and the fish
died in 15 minutes. Test number 21 was prepared by mixing one
liter of 100 p.p.m. KCN with 150 cc of .01% lime-sulphur solu-
tion. This was also aerated continuously and the fish died in
15 minutes.

INTERPRETATION OF RESULTS
In lower dilutions of both potassium cyanide and lime-

sulphur, the experiments were more successful, however, outside

physical or chemical factors may have caused this difference.

16

With the higher concentrations, the results were very unfavor-
able. The action of the gold fish indim ted that the treat—
ment was not satisfactory. Their reactions to the lethal ef-
fects of the treated cyanide waste proved quite conclusively
that they were suffering from lack of oxygen. This was due

to the toxic effects of the cyanide. The physiological action

of t‘e fish was exactly that of a cyanide poisonin: as des-

3
cribed in medical handbooks. Their reactions are first stimu—
lated and later depressed until finally death occ urs due to

aSphyxia. The fish had extremely red gills which was likewise

a s1gn of cyanide p01son1ng.

S'MTARY OF FY PF RIHEKTAL RFE UL T

(I)

, AIJD CF VCLUSICNS

From the results of the eXperimental test run, it appears
that the lime-sulphur lacked the ability to convert the cyanide
to a cyanate or some other cyanide compound w' hich is stable and
much less or not at all toxic to fish life. This fact was
shown more conclusively in the stronger concentrations of potas-
sium cyanide. However, there is some chemical reaction which
occurs when KCN and lime-sulphur are mixed together. A concen-
trated solution of KCN mixed with a small amount of lime-sulphur
quickly formed a yellow colored precipitate which may have been
free sulphur.

1

It is the writer's opinion tnat further study is warranted
of this treatment by persons having more time as well as a better
understar nding of the chemistry involved. Having been called to

active duty in the army cut short the experimental work of this

thesis.

l7

Barr u 1: x , ~ i

O

(l) "The Removal lof Cyanides froux Platin 3 Room Vaste". Micnivan

Engineering EXperiment Station Bulletin #5?.

(2) "The Fffects of Cyanide on Trout". The Black Hill.s En aim er.

.4

The South Dakota State School of Mines. May 1954.

(5) "Practical Veterinary Pm acolov', Materia, Medica, Thera-

peutics" by Howard Jay Milka ,D.V.M.

(4) "Detection and Measurements of Stream Pollution" by M. M.
Ellis.
United States Department of Commerce; Bureau of Fisheries,

Bulletin #3?.

 

 

 

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‘.