FROTH FLOTATION CONCENTRATION OF AZURITE AND MALACHITE ' 1N ALKALINE EARTH GANGUE MATERIALS Thesis 'fcr‘ the. Degree of ML 5. {WCHIGAN STATE COLLEGE Philip Alfred Lenton . 1943 - 7 A. -.~ “pa—‘-- e . __._. , This is to certify that the thesis entitled r r r- ‘ ‘v r— » - 7 . A .J‘- l - '.. .. v' ' 1 ' '- r ‘.,, .. ,1 , ., v f P V Ff. ’ Y Y— ; .I A l , r; v r . '..): has been accepted towards fulfilment of the requirements for '..Li. degree in 7?;m." L Major professor Date [2; 7L, ;_J’1.r' ' V'. I I. '. p. ‘ I 7‘ '.QA ‘..“ ‘1 - . ;‘ I ; Vikki: $4“. “I: g 1Q . . . N I...“ ~. p_!‘ .“I .- f a? 1 V" '1 3‘? 1 ',.:’ (.35, -l .‘ ‘s‘ ‘ J ’ " '7 Q ~'- ‘V, \‘J‘ \1 H. " i I T i“: n I v‘ r d ‘1'“ .32.. *" 4‘ J" V ‘Y .‘n .r . .3. ”If; 3 ,. .. E ,- . _o :0 , FROTH FIDTATION CONCENTRATION OF AZURITE AND MAIACHITE IN ALKALINE EARTH GANGUE MATERIAIS by PHILIP ALFRED ‘lfiTON A THESIS Submitted to the Graduate School of Michigan State College of Agriculture and Applied Science in partial fulfilment of the requirements for the degree of MASTER OF SCIENCE Department of Chemical Engineering 1943 THESIS- TABLE OF CONTENTS ACICNOWIEDGEEIENTSoooooeoeeeoeooooooeooooeooo INTRODUCTIONOOOOOOOOO00000000000000.0000... HISTORYoeeoeee0000000000900000000009...0000 THEORYOOOOO000......QOOOOOOOOOOOOOOQOOOOO.0 PICTURES OF APPARATUS............ooo... 15, PROCEDUREooeeeeeeeeeeeeeeeeeeeoeeeeeooeeoee DATA AND GRAPHS.....o...........o.o.o..oo.. DISCUSSION..........oooo.....o............. CONCIUSIONS................................ BIBIIOGRAPHY............................... 00001 14 15 20 44 55 57 ACKNOWLEDGEMENT The author is deeply indebted to Professor C. C. DeWitt for his guidance and for his valuable advice. Appreciation is also expressed to the members of the chemical engineering staff for their assist- ance and to Dr. J. A. Young for his aid in the identification of minerals. INTRODUCTION In Alaska, Arizona, and other sections of the North American continent there exist comparatively large quanti; ties of capper carbonate ores. The cepper exists as malachite (Cu005-Cu(0H)2) and azurite (20u003°Cu(0H)2). Unfortunately, there is present in the ores a large amount of impurities which consist principally of dolo- mite (CaCOS°MgC03) and calcite (CaCOB). Some of the ores, however, also contain large quantities of silica and some capper in the form of chrysocolla (CuSioaoZHzo). The separation of the cepper carbonate minerals from the alkaline earth gangue materials by froth flotation was undertaken as a research problem. Froth flotation has been used quite successfully for some time in the separation of precious metal minerals from gangue. However, the flotation of these copper carbonates has not, to the author's knowledge, been placed on a commercial basis because of the excessive amounts of reagents required for the separation. The literature was reviewed in an attempt to find a net collecting reagent and to investigate the vork already done on copper carbonate ores. Flotation tests were run and data collected by the use of a flotation cell built of Lucite in the Chemical Engineering Laboratories of Michigan State College. The separation of malachite and azurite from dolomite and calcite in synthetic mixtures containing 1% of the cepper mineral was successfully completed, employing xanthates as collecting agents. Many less successful runs were made using various collecting agents. In addition,tests were carried out using naturally occurring ores from Alaska and Arizona. The data presented herein have not completely solved this problem, but certainly the conclusions which can be reached from the results will prove very valuable to future work on this and similar research. HISTORY Although chalcocite (Cuzs) has been successfully separated from gangue for some time by froth flotation, the separation of oxidized copper minerals has not been satisfactorily accomplished. Taggart (4) lists three general methods attempted in the flotation of oxidized base-metal minerals. These are: (l) sulphide-filming processes; (2) solution and precipitation as sulphide or metal; and (3) selective oxide-flotation. The first method, although suitable in some cases, is not satis- factory in the case of most capper carbonate ores. A variation of the second method was used with oxidized cepper ores in Arizona. (5) The ores were leached with sulfuric acid and the copper was recovered by electro- deposition. The third method, that of selective flota- tion of the oxidized copper mineral, has been used on Katanga ores containing malachite and azurite. (3) Several attempts have been made to separate malachite and azurite from gangue by selective flotation. DeWitt and von Batchelder (8) achieved some success in separating azurite and malachite from a siliceous gangue, using oximes as flotation reagents. The experiments were carried out with synthetic mixtures containing slightly less than 1% of the cepper mineral. Recoveries were recorded as high as 97.7%, with the concentrate reaching about 34% cepper in the case of malachite. Lower values were recorded for azurite. The pH of the solution was kept in the range of 4.0 - 5.0. With regard to the separation of malachite and azurite from synthetic mixtures containing calcite, Gaudin and Martin (12) contributed much. The mixtures that they worked with contained 10 grams of the capper mineral to 40 grams of the calcite or, in other words, 20% of their ore was mineral. Experiments with fatty acids as col- lecting agents showed that, although the malachite and azurite floated, a separation from the calcite was not possible because the calcite also floated equally as well. Results obtained by these authors using various xanthates as collectors were presented and proved to be much more satisfactory. Practically complete recovery of malachite and almost complete separation from calcite were obtained using potassium iso-amyl xanthate as the col- lecting agent. The concentration of the reagent necessary for this separation was three pounds per ton of ore. Results obtained by the use of mercaptans and other organic hydrosulphides as collectors were also fairly good. In a later paper, Gaudin and Anderson (11) continued this work. Many new collectors were unsuccessfully tried. The effect of pH upon the separation of malachite from calcite was shown and, according to their results, the recovery changed considerably with a change in pH. When inorganic reagents were added before adding the collector, a depression of the malachite resulted. However, the addition of lead or zinc nitrate improved the separation remarkably. A good separation was obtainable using two pounds per ton of potassium secondary butyl carbinol xanthate as a collector after first conditioning with the lead or zinc nitrate. THEORY Although the term flotation would lead one to be- lieve that the separations depend upon the densities of the various particles, this is certainly not the case in froth flotation. The fact is true, of course, that gravity separations are still in use, but, since 1912, (5) differential froth flotation has increased in importance until it is now used in the concentration of practically all minerals. Several steps are involved in the froth flotation process. They are as follows: (1) the ore is crushed to a state where the mineral particles are free of the gangue material; (2) the crushed ore is suspended in water which contains various reagents, and these reagents, together with agitation and air, cause the mineral particles to cling to the rising stabilized air bubbles; (3) the bub- bles, lined with the minerals, are then floated from the surface and the concentrated mineral may then be either further concentrated by the same process or it may be suitably treated as such for the recovery of the metal.(7) The four functional reagents used in froth flotation are defined by Wark (5) thus: "A frother is a substance (generally organic) which, when dissolved in water, enables it to form a more or less stable froth with air. 10 "A collector for any mineral is a substance (generally organic) which induces it to float at the air-water interface and, in the presence of a frother, to form a more or less stable mineralized froth. "An activator for any mineral is a substance (generally inorganic) the addition of which induces flotation in the presence of some collector that other- wise is without effect on the mineral. "A depressant for any mineral is a substance (generally inorganic) the addition of which prevents a collector from functioning as such for that mineral." Frothers are almost entirely organic compounds whose molecules each contain one polar group and one non-polar group. These frothers act upon the gas-liquid interface, not at the surface of solids. They should not ionize appreciably as this would give them collecting preperties. (Proper control of flotation processes is difficult if the frothers collect also.) Several investigators have showed that the frothing power of a reagent is related to the lowering of surface tension when that reagent is added to water. For example, DeWitt and Makens (9) found that the frothing agent with the most negative slepe on a surface tension-molar concentration curve was the most efficient frother. Collecting agents are similar to frothers in that they are also heteropolar, but collectors should be ionized to a greater extent. Furthermore, the polar part ll of collectors should have a specific affinity for specific minerals whereas the polar part of frothers should have affinity for water only. (3) The purpose of the collector is to cover the mineral at least partially with an organic compound. Two Opposing theories have been presented to explain the mechanism of this film formation. Taggart and his collaborators believe that this film is an insoluble precipitate. This may result either from double decomposition at and with mineral surface atoms or by adsorption at the mineral interface from saturated solutions of difficultly soluble substances. The Opposing adsorption theory adopted by Wark (5) suggests that the collector ions are merely adsorbed at the mineral surface. The adsorption is dependent upon the degree of insolu- bility of the compound formed by the cation of the mineral surface and the anion of the collector. Both of these contentions are supported by experi- mental data, and it would not be surprising if there were cases where one was applicable and other cases where the apposite theory was true. At any rate, the result is essentially the same in either manner of formation. The film that is formed has non-polar groups projecting away from the mineral. These non-polar groups will, of course, seek out the non-polar air in preference to the polar water, with the result that the mineral particles adhere to the air bubbles. In other words, "the object of coating a mineral with an insoluble or tenacious organic 12 film is to give it the property of exhibiting a finite contact angle in the presence of air--i.e., to make it possible for the air to displace the water partially from the coated mineral surface in order to make the mineral particle surface less easily wetted by water." (7) As in the case of the frothers, in a homologous series of collectors, the one possessing the most negative slepe of the surface tension-concentration curves will be the most effective. A word of explanation might be added here with regard to a few of the other terms used in this paper. "Heads" refers to the charge into a flotation cell. "Concentrate" refers to the material collected in the overflow and the solids remaining in the liquid are called "tails". The percentage recovery refers to the fraction of the total mineral in the heads that was present in the concentrate. . é . - ' ' I' il‘ .-.-- ; 1 . g‘ ' ' ' - :1. g - l 1|] 111 l hill"; :- 2 a s». .-, '3 I waif-r I. ”Ln A :q . . . . . . I _ - '7? APPARATUS SIDE VIEW 15 APPARATUS FRONT VIEW l4 15 PROCEDURE All minerals and ores used in the research were first crushed to size in a small Chipmunk Jaw crusher. After crushing, the material was sized, using a standard set of screens. A Denver screen shaker was used in the sizing in most cases although some screening was done by hand. The portion passing through the 40 mesh screen but remaining on the 60 mesh screen was taken for experimentation almost exclusively. The capper minerals, ores, and the concentrates from the flotation runs were analyzed for cepper using the method of Park. (15) The samples were dissolved in concentrated nitric acid. The solution was aided by the use of two or three drops of concentrated hydrochloric acid which did not affect the analysis appreciably. After treatment with ammonium hydroxide and ammonium bifluoride, potassium iodide was added and the iodine liberated was titrated with .1 N sodium thiosulfate solution. The latter was prepared according to Willard and Furman. (6) In the case of the larger concentrates, aliquot portions were taken for analysis after the samples were dissolved. The flotation runs were carried out in a flotation cell constructed of the transparent Incite so that the material in the cell could be observed. The cell, 100 gram 16 capacity, was built of one-fourth inch Incite sheets glued together by a special acetone-Lucite cement. (14) The material in the cell was agitated by a stainless steel impeller driven by a one-sixth horsepower electric motor. An air compressor introduced air through the bottom of the cell. The air line, in addition to step cooks for control, also contained a calcium chloride tower packed with glass wool to remove any oil from the compressor. The froth overflow, at the front of the cell, was sloping and a baffle was placed before it to prevent particles from being pushed over by the action of the stirrer. A small outlet was made in the bottom of the cell for the removal of the tails after a run. The froth overflowed into a Buchner funnel and the filtrate was removed by a vacuum created by a water aspirator. This filtrate was drawn up into a small reservoir and, from time to time, the vacuum was released and the filtrate was returned to the cell. In this way, although the level in the cell was not constant, re-use of the froth water was possible and no make up water was necessary. In preparation for a test, the impeller and the air were started, the ore was placed in the cell followed by water, and then the accurately weighed collector, in solution, was added. Unless otherwise indicated, there was, in all runs, an agitation period of three minutes. A frother, pine oil, was used in most of the tests and 17 this was put in the cell by dipping a small wire into the pine oil and then dipping the wire into the water in the cell. After three minutes, more water was added and the air was increased so that the froth overflowed into the funnel. The froth was collected for six minutes, after which time the material on the filter paper was dried, first by the vacuum from the water aspirator and then in an electric oven at 1000 C. for twenty to sixty minutes. The drying time depended on the size of the concentrate. After drying, the concentrate was weighed and analyzed for cepper. The concentration of copper and the percentage recovery could then be calculated. After some runs a sample of the solution remaining in the cell was taken and the pH was measured with a Beckman pH meter. After all runs the tails were removed and inspected visually, sometimes with the aid of a micro- scepe. In the first series of tests an effort was made to find a suitable collector to separate azurite from dolo- mite. The runs were made on synthetic mixtures containing ninety-nine grams of dolomite and one gram of azurite. For the more successful collectors, the xanthates, various graphs were prepared showing the effect of the concen- tration of the collector upon recovery and concentration. The most successful collector, potassium n-decyl xanthate, was also used in runs separating malachite from dolomite, malachite from calcite, and azurite from calcite, where the 18 copper mineral was 1% of the mixture. Several experimental runs were made on an ore from Alaska using potassium n~decyl xanthate as the collector. Among these were some dilution runs, showing the effect of diluting the ore with dolomite. Other more successful runs were made by first "desliming" the ore. Before flotation the ore was washed in a beaker and the liquid was decanted. This process was repeated several times until the liquid seemed to be free of any green color. In some cases the washings were analyzed for cepper also. Less successful runs were made on fine Alaskan ore after a similar "washing" operation. Runs were made on an ore from Arizona using potassium n-decyl xanthate as a collector on the washed ore. An unsuccessful attempt was made to float the Alaskan ore in an acid circuit using salicylaldoxime as a . collecting agent. Sulfuric acid was used for acidification. The xanthates used in this research were prepared by the methods suggested by Foster. (10) The lower xanthates were made by first dissolving potassium hydroxide in the alcohol to form the alcoholate and then allowing the alcoholate to react with excess carbon disulfide. The yellow precipitate was filtered, washed, and recrystal- lized from mixtures of acetone and benzene. In the preparation of potassium n-decyl xanthate, a saturated solution of potassium hydroxide was added to the alcohol and the carbon disulfide was added to the mixture in an ice bath. Constant agitation was provided and the precipitate formed was purified by recrystallization. 19 DATA 20 21 SOURCE OF MINERAIS DOLOMITE Obtained from the Inland Stone and Lime Company at Manistique, Michigan. CAICITE Obtained from the Michigan Alkali Company. This limestone probably came from the region of Alpena, Michigan. AZURITE Obtained from the Ward Natural Science Company. Found by analysis to contain 45,6% Cu. MAIACHITE Obtained from the Ward Natural Science Company. Found by analysis to contain 52.65% Cu, ALASKAN ORE Obtained from the Kennecott Copper Company by courtesy of E. T. Stannard. Contains azurite and male- chite with apparently traces of chrysocolla. Found by analysis to contain 9.38% Cg; Calcite and dolomite present in large quantities. ARIZONA ORE Obtained from the Phelps Dodge Company by courtesy of F. Kohlhaas. Contains malachite as the predominate capper mineral but also contains fairly large amounts of chrysocolla and traces of other cOpper minerals. Found by analysis to contain 3.94% CuL Silica present in large quantity. _* 22 The following runs were made on a synthetic mixture of one gram of azurite and ninety-nine grams of dolomite. The collectors were all used at a concentration of two pounds per ton. C OLLECT OR Benzyl Amidoxime Malcnic Hydroxamic Acid Sodium Pectate‘ Reagent * 425 Oleic Acid Acetc Hydroxamic Acid Diphenyl ** Thio Carbazone FROTHER Pine Oil N o no Pine Oil TABLE 1 % RECOVERY 2.04 3.50 2.12 23.1 11.9 4.40 % CONCENTRATION OF MINERAL .47 .64 .91 1.81 .59 .83 * Sample furnished by the American Cyanamid Company. ** Dissolved in ethyl alcohol instead of water. 23 TABLE 1 (Cont.) COLLECTOR FROTEE 7% RECOVERY % CONCENTRATION OF MINERAL Oleic * Pine 011 20.8 .55 Acid Salicyl- " " 7.65 1.28 aldoxime PrOpion " " 2.42 .89 Hydroxamic Acid PrOpion " " 3.40 .69 Amide Trimethyl " " Negligible Cetyl Ammonium Bromide Trimethyl " ” No analysis-~recovery poor Benzyl Ammonium Hydroxide Duprex-20 ** N '1 n N H n * The acid was mixed with 2.6 m.l. of kerosene. ** A methylated pectin furnished by General Foods Company through the courtesy of Dr. Kramer. 24 The following runs were made on a synthetic mixture of one gram of azurite and ninety-nine grams of dolomite. The collectors were used at a concentration of two pounds per ton. The frother was pine oil. TABLE 2 COLIECTOR SODIUM TETRA- % RECOVERY % CONCENTRATION PHOSPHATE OF MINERAL Amyl * None 48.0 6.65 Xanthate .087 gm. ** 3.57 .81 .102 gm. *** 20.9 5.67 Potassium None 87.9 17.3 n-Heptyl Xanthate .113 gm. *** 87.5 24.9 * Sample from the American Cyanamid Company. ** The sodium tetra-phosphate was added and the mixture was agitated for one minute before the collector was added. *** The collector was added and the mixture was agitated for three minutes before the sodium tetra- phosphate was added. The use of sodium silicate and Reagent 712 (American Cyanamid Company) as depressants was also tried with no success. 25 The following runs were made on a synthetic mixture of one gram of azurite and ninety-nine grams of dolomite. The frother used was pine oil. TABLE 3 COLLECTOR CONCENTRATION 3% RECOVERY $6 CONCENTRATION OF COLLECTOR 0F MINERAL Potassium .5 #/ton 44.0 9.40 n-Amyl 1.0 " 57.3 19.4 Xanthate 2.0 " 75.2 22.6 Potassium .5 #/ton 61.7 13.0 n-Hexyl 1.0 " 85.0 21.5 Xanthate 2.0 " 83.5 18.7 Potassium .5 #/ton 66.6 22.4 n-Heptyl 1.0 N 90.1 2701 Xanthate 2.0 " 87.9 17.3 Potassium .1 #/ton 2.98 .88 n-Decyl .3 " 12.1 5.63 Xanthate .4 " 59.6 12.2 .5 " 88.5 22.1 .7 " 98.5 19.9 1.0 " 96.1 19.5 2.0 " 97.1 15.1 26 zoo °K-n3— x... at. a- Mate k 80 ,_ . i 7 iK-II- es’ll leaflet: 2 5 ~ , w a - IL : I ' IK‘II' 5’4"” :X‘A (ACCQ 9 Q i i Q r 40 , ‘32 l ‘3‘ ; O * u [t 20 , u 0 hit k§ 40 w sh 2k We 3?? 20 8% 00 0.5 1.0 1.3- 2.0 I XAN THA 72:, LB. / rozv Graph 1.--Flotation of azurite from azurite- dolomite mixtures with normal potassium xanthates. 27 The following runs were made on the synthetic mixtures as indicated, using potassium n-decyl xanthate as the collector. MIXTURE Malachite- Dolomite Malachite- Calcite Azurite- Calcite CONCENTRATION OF COLLECTOR .3 #/ton . n .7 " 1.0 " 2.0 " e5 #/t0n .7 n 1.0 ” 05 #/ton .7 " 1.0 " 2.0 " TABLE 4 % RECOVERY 11.7 78.5 97.5 98.5 97.3 8.60 28.0 75.8 87.7 16.0 67.3 76.1 85.7 Pine oil was used as the frother. % CONCENTRATION OF MINERAL 1.24 21.4 25.8 20.4 15.5 1.76 5.70 8.55 8.40 2.16 8.20 10.5 8.75 1 Graph 2.--rlotation of malachite from malachite- dolcmite mixtures with potassium n-decyl xanthate. c ONCEN TRA 76', PH? (‘fo MALACH/TE RECOVER y ,psn CENT 100 Ch 0 60 40 20 40 20 O 0 0.5 A l——- —__4 _._, i L 1.0 I ——-—< i 4 Yfii—q ‘ i '2.0 DEC YL XAN THA TE 1 LB. / TON 28 100 J I WM! (M: J!!! PER CENT RECOVER y , cozvcawrnA 7:, PER cew 7' M/NERAL °o MI. “I: to I \ 0.5 1.0 105 05c r1. XANTHA TE , 2.0 L8./7‘0N A 29 Graph 3.--1'lotation of azurite and malachite from calcite mixtures using potassium n-dccyl xanthate as a collector. 30 The following runs were made on one hundred gram samples or the Alaskan ore. The collector used was potassium n-deoyl xanthate and the frother was pine oil. TABLE 5 CONCENTRATION % RECOVERY % CONCENTRATION OF COIlECTOR OF COPPER .5 #/ton 9.23 20.2 .5 " 8.08 17.2 1.0 " 11.5 20.4 2.0 " 12.6 18.1 40 20 RECOWSPY; xasp czvvr 40 1D 20 COAmzwvznArzy IQE5’1QSN7'CZV¥WDQ ’ O O: 1.0 1.5 2.0 L DECYL XANTHA re: , L a. / TON Graph 4.--Flotation or copper minerals from an Alaskan ore using potassium.n-decyl xanthate as a collector. 32 A run was conducted on one hundred grams or the Alaskan ore which was less than 100 mesh. The collector was potassium n-decyl xanthate at a concen- tration of one pound per ton. Pine oil was the frother. % RECOVERY % CONCENTRATION OF COPPER 29.2 * 14.7 * This is making the assumption that this ore had the same original analysis as the 40-60 ore. 53 pH Values of Solutions Material Avg. PH Azurite-Dolomite 8.0 Malachite-Dolomite " Azurite-Calcite 8.0 Malachite-Calcite " Alaskan Ore 6.9 Arizona Ore 8.1 The following runs were made on one hundred gram samples of the Alaskan ore. The collector was potassium n-decyl xanthate at a concentration.or one pound per ton. The frother was pine oil. Sodium carbonate solution was used to regulate the pH. TABLE 6 SODIUM CARBONATE pH % RECOVERY’ % CONCENTRATION OF COPPER None 6.9 11.5 20.4 1.25 gme. 9.0 14.0 28.1 2.50 gms. 9.5 14.2 31.0 3:: 40 Q $3 at: so — It“ ._ in? A- ' f o t \N {3% 40 Q3 1 lkk r, 3%: 20 t 20 We 101.4 7 Q O to so so pH Graph 5.--Erfect or pH othhe flotation or an Alaskan ore with potassium n-decyl xanthate as a collector. 35 The following results were obtained using mixtures of the Alaskan ore and dolomite as indicated. Pine oil was used as a frother and the collector was potassium n-decyl xanthate at a concentration of one pound per ton of material. TABLE 7 % AIASKAN ORE % RECOVERY % CONCENTRATION OF COPPER 100 11.5 20.4 50 12.9 14.8 25 15.1 17.7 18 58.5 50.0 15 55.2 50.5 10 95.5 21.3 5 94.2 10.0 100.0 5.55 2 A run using a saturated dolomite solution instead of water as the flotation medium gave the following results. The heads was one hundred grams of the ore. % RECOVERY % CONCENTRATION OF COPPER 10.2 25.1 zoo Q 0 Ad”.— PIR CENT .. \ cho VER y , 20 \_ 4O CONC£IV 77‘“ 7'5, PER cswr COPPER .. 4/1 J OZ 0 20 40 ~ so so 100 ALASKAN one; PER cavr Graph 6.--Flctation of copper minerals from.Alaskan ore-dolomite mixtures using potassium n-decyl xanthate at a concentration of one pound per ton of mixture as a collector. 36 37 The following run was made on one hundred grams of the Alaskan ore, using pine oil as a frother and .salicylaldoxime as the collector. The concentration of the collector was two pounds per ton of ore. Before addition of the collector the solution was made acid by the addition of three milliliters of concentrated sulfuric acid. pH % RECOVERY % CONCENTRATION OF COPPER 4.8 2.82 5.45 Runs using propionhydroxamic acid as a collector at pH values of 3.8 and 5.4 also gave poor results. 38 The following results were obtained from one hundred gram samples of Alaskan ore which were "deslimed" before flotation. The frother was pine oil and the collector was potassium n-decyl xanthate. TABLE 8 CONCENTRATION % RECOVERY % CONCENTRATION OF COIIEETOR OF COPPER 1.0 #/ton 32.4 46.4 1.5 " 65.5 44.4 2.0 ” * 98.6 ** 51.4 * An analysis of the slimes washed out showed that they contained 2.5% of the original copper. The total of more than 100% copper is due to the method of sampling. ** This run was repeated with the same result. 39 100 TF‘ L. 80 // 2 3 / ct / In so “ / Q j q 40 A / 8 / w . T Q: 20 o 0% 7T c; 0 4o '93 «4% 0M 2" 20 3E 0. o 0 our .20 zsr .20 ascrz.x4~nvwant , Ltlz’TZVV Graph 7.--FlOtation of copper minerals from a deslimed Alaskan ore with potassium n-decyl xanthate as a collector. 40 The following results were obtained from one hundred gram samples of Arizona ore which were ”deslimed" before flotation. The frother was