FLOTATION OF CASSITEEITE BY ALKYL SUBSTITUTED NITRO PHENOLS AND NITRO RESORCINOL ETHERS By Ishwarbhai Ashabhai Patel A THESIS Submitted to the School of Graduate Studies of Michigan State College of Agriculture and Applied Science in partial fulfillment of the requirements for the degree of DOCTOR OF PHILOSOPHY Department of Chemical Engineering 1953 ProQuest Number: 10008401 All rights reserved INFORMATION TO ALL USERS The quality of this reproduction is dependent upon the quality of the copy submitted. In the unlikely event that the author did not send a complete manuscript and there are missing pages, these will be noted. Also, if material had to be removed, a note will indicate the deletion. uest. ProQuest 10008401 Published by ProQuest LLC (2016). Copyright of the Dissertation is held by the Author. All rights reserved. This work is protected against unauthorized copying under Title 17, United States Code Microform Edition © ProQuest LLC. ProQuest LLC. 789 East Eisenhower Parkway P.O. Box 1346 Ann Arbor, Ml 48106- 1346 ACKNOWLEDGMENTS To Dr. Clyde C. DeWitt acknowledgment is made for recognizing the feasibility of using 2-Nitro ^4-Alkyl Phenols and 2-Nitro Resorcinol ethers as flotation agents for Cassfeterite ore; and for his interest in and guidance throughout this research work* Thanks are also due to Dr. Herold A Price of the Engineering Experiment Station for helpful suggestions and encouragement during this work* Ishwarbhai Ashabhai Patel candidate for the degree of Doctor of Philosophy- Final examination: February 26, 1953» 10-12 A.M., Room 301 Olds Hall. Dissertation: Flotation of Cassiterite by Alkyl Substituted Nitro Phenols and Nitro Resorcinol Ethers. Outline of Studies: Major Subject: Chemical Engineering Minor Subjects: Metalli*rgical Engineering and Physics# Biographical Items: Born: December 9» 1926; Chikhodra, Bombay State; India. High School Graduation: 19^5* Sharda High School, Anand; Bombay State India. Undergraduate Studies: V.P. College; Vallabh-Vidra-Nagar, Anand; Bombay State, India. (B.Sc. with Chemistry and Physics; University of Bombay, 19^9 .) Graduate Studies: M.S., 1951* (Chemical Engineering) Michigan State College# TABLE OF CONTENTS PAGE I. INTRODUCTION............................................ Purpose and Scope Theory ............................... 1 ........................................... 2 Previous Work on CassiteriteFlotation . . . II. ......... 7 EXPERIMENTAL W O R K ........................................ 10 Design of Collector Flotation Machine Particle Size III. 1 . . . . . . . . 11 ................................. 12 ............... 12 Pulp Density............................... 15 Addition of Reagents....................... 15 Experimental Procedure........................... 16 DATA AND RESULTS .................................... 17 Tables 1 - 8 .............. ... ..................... .. IS Graphs, Figures 3 - 2 2 ............................. . . 26 Discussion of R e s u l t s ................................46 General' Summary and Discussion..................... IV. §2 CONCLUSION................................................ 54 APPENDIX.............................................. General Discussion............................... .. 56 5j Synthesis of 2 - NitroResorcinol E t h e r s ............... 57 Synthesis of 2 - Nitro 4alkyl Phen o l s................. 60 BIBLIOGRAPHY..............................................63 LISf Or TABLES PAGE Table 1. Flotation of Cassiterite byN A P - 1 0 .................... 18 Table 2. Flotationof Cassiterite byN A P - 8 .................... 19 Table 3* Flotation of Cassiterite byN A P - 6 .................... 20 Table Flotation of Cassiterite by N R E - 1 0 .................... 21 Table 5» Flotation of Cassiterite byN E E - 8 .................... 22 Table 6, Flotation of Cassiterite byN R E - 6 .................... 23 Table J. Table 8. Flotation of Cassiterite byNAP-10 and NRE-10 Flotation of Cassiterite byNAP-10 .... 2k .............. 25 LIST OF FIGURES PAGE 1. Flotation Cell ( D r a w i n g ) ............................. 13 2. Flotation Cell (Photograph) . ......................... 1^ Percent Recovery and Enrichment as a Function of pH 3. 0.20 Lb./Ton C o l l e c t o r ............................... 26 h. 0.10 Lb./Ton C o l l e c t o r ............................. 5. 0.06 Lb./Ton C o l l e c t o r ............................... 28 6. 0.03 Lb./Ton Collector ... .. ................... 27 29 Percent Recovery and Enrichment as a Function of Collector Concentration 7. N A P - 1 0 ............................ 30 8. NAP-8 ............................................... 31 9. NAP-6 ............................................... 32 10. N R E - 1 0 ............................................... 33 11. NRE-8 ............................................... 34 12 . NRE- 6 ............................................... 35 Pounds Tin Recovered per Pound of Collector and Improvement Factor as a Function of pH 13. 0.20 Lb./Ton C o l l e c t o r ........................... 36 lH-. 0.10 Lb./Ton C o l l e c t o r ........................... 37 15» 0.06 Lb./Ton C o l l e c t o r ............................. . l6 . 0.03 Lb./TonC o l l e c t o r .................................35 3g LIST OF FIGURES (Cont.) PAGE Pounds Tin Recovered per Pound of Collector and Improvement Factor as a Function of Collector Concentration ........................................... ^0 17 . NAP-10 . 18. NAP- 8 ............................................... 4l 19. NAP- 6 5+2 20. N B S i - 1 0 ................................................. U3 21. NRE-S 22. NRE-6 .............................................. ............................................... ^5 Solid Surface Graphs, Percent Recovery, Enrichment, pounds Tin Recov­ ered per Pound Collector, and Improvement Factors Varying with pH and Collector Concentration 23. NAP:Recovery and Enrichment......................... Pocket 2^. NAPs Improvement Factor and Lb. Tin/Lb. Collector. . • Pocket 25. 26. NRE:Recovery and Enrichment. ............... Pocket NREsImprovement Factor and Lb. Tin/Lb. Collector. . . Pocket I N T R O D U C T I O N INTRODUCTION Tin generally exists as an oxide* as Cassiterite* Tin oxide is commercially known Its chemical formula is SnOg* Economically important deposits of comparatively pore cassiterite are found in Bolivia, Malaya, and China. In the United Statets of America there exists a large quan­ tity of tin ore which contains less than 3 percent of tin. With the increasing use of tin metal in war production and the fact that rich tin ores will presently not he available in large quan­ tities in these countries, a method should be developed to concentrate the low grade tin ores* One of the easiest and the cheapest methods for the concentration of cassiterite is froth-flotation. Froth flotation has been used quite successfully for some time in the separation of non-ferrous minerals. The method is particularly well adapted to the recovery of the insoluble sulfides of the metals. It has also been extended to the separation of the other oxide ores. Work has been done on the flotation of cassiterite using organic chemicals as frothers and col­ lectors, but the work has not yet been put on commercial basis*^ PURPOSE AND SCOPE The purpose of this investigation was to show that the Nitro alfcyl Phenols, and the Nitto resorcinol ethers act as collectors in the flotation of cassiterite. Three chemicals of each series are used having a carbon atom chain of 6 , 8 and 10 carbons, for each series* 2 For identification, the following short designations are employed for the chemicals which are used as collectors* (1) (2) (3) 2-Nitro H-hexyl p h e n o l -------------------- ----- ----- NAP-6 2-Nitro octyl p h e n o l ------- - - NAP-S 2-Nitro ^decyl phenol---------------------------------- NAP-10 (4) 2-Nitro hexyl resorcinol ether (5) 2-Nitro octyl resorcinol ether (6) 2-Nitro decyl resorcinol ether ----- - - - - - - - - - - NRE-6 -- - - - - NRE-S -------- NRE-10 THEORY Although the term flotation might lead one to "believe that the separation depends upon the densities of various particles, this is certainly not the case in froth flotation. that gravity separations are still in tial froth flotation has increased in The fact is true, of course, 50 use, but since^1912 , differen­ importance untilit is now used in the concentration of many economic minerals* Several steps are involved in the froth flotation process* steps are as follows: (l) the ore is These crushed to a state where the min­ eral particles are free of the accompanying gangue materials; (2 ) the crushed ore is suspended in water which contains various reagents, and these reagents together with agitation and air, cause the mineral par­ ticles to cling to the inside of the rising stabilized air bubbles; (3) the bubbles, lined with the mineral particles, are then skimmed from the surface. The concentrated mineral may be further concentrated by the same process or it may be suitably treated for the recovery of metal.^ 3 The four functional reagents; the frother, the collector, the activator and the depressant; used in froth flotation are defined by Wark and DeWitt^ as follows: FROTHERS: A frother is a substance (generally organic) which when dissolved in water, enables it to form more or less stable froth with air* Frothers are almost entirely organic compounds whose molecules contain one polar group and one nonpolar group. These frothers act upon the gas-liquid interface, and not at the surface of solids. They should not ionize appreciably, as this will give them collecting proper­ ties. Several investigators have shown 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 8 found that the frothing agent with the most negative slope on a surface tension-molar concentration curve was the most effective frother. Some of the commonly used frothers are: terpeniol, amyl alcohol, and soaps. pine oil, eucalyptus oil, The frother should not act as a collector, nor should it be used in excess. An excess of frother has a tendency to coat the ore particles thus excluding the collector anfl decreasing the efficiency of flotation. The amount of frother commonly used lies between 0.05 and 0.20 pounds per ton. COLLECTORS: A collector for any mineral is a substance (generally organic) which induces it to float at the air water interface, and, in the pres­ ence of frother to form more or less a stable mineralized froth. k Taggart^ states that the collectors mast "be soluble in water at least to a small degree. Collectors are similar to frothers, hut the collectors should be ionized to a greater extent. Furthermore, the polar part of the col­ lector should have a specific affinity for specific minerals, whereas the polar part of the frothers should have affinity for water only. 1«5 The purpose of the collector^ is to attach itself to the mineral and present an outward oily film to the air bubble. One end of the collector contains an active polar group, and the other end is a hydrocarbon chain (non-polar group). The length of the hydrocarbon group on a collector which permits flotation depends upon both the mineral to be recovered and upon the active polar group in the collector molecule. The present day views about the mechanism of the collector action are given by two hypotheses. (1) The chemical reaction hypothesis, and (2) the adsorption hypothesis. The chemical reaction hypothesis is stated as follows by Taggar$, hg Taylor and Knill . MA11 dissolved reagents which in flotation pulp, either by action on to-be-floated or on not to-be-floated particles affect their flotability function by reason of chemical reaction of the well recognized types between the reagent and the particles affected." The adsorption hypothesis which as adaptedby Warir*® may be stated as follows: The ions dissolved in a flotation pulp liquor adsorb at the mineral surface. The adsorption of each dissolved ion is specific^ i.e. it depends on the dissolved ion on the mineral. This specific ion adsorption is also a function of the concentration of the dis­ solved ion under consideration, as related to that of the other dissolved 5 ions. If and when a sufficient proportion of the mineral surface is covered "by the effective collector ions, the particles become flotable. The film that is formed, has non-polar groups projecting away from the mineral. These non-polar groups will seelc out the non-polar air in preference to 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 organic film is to give it the property of exhibiting a finite contact angle in the presence of air, i*€i«, to make it possible for the air to displace the water partially from the coated mineral surface in order to make the mineral particle q surface less easily wetted by water.-' In case of collectors, as in the case of frothers, the collector possessing the most negative slope of surface tension - concentration curve will be the most effective. ACTIVATORS An activator for any mineral is a substance (generally inorganic), the addition of which induces flotation in the presence of some collec­ tor that otherwise is without any effect on the mineral. Heavy metal sulfides are readily caused to float by the use of xanthate collectors. The oxidized minerals do not have this property. DEPRESSANT When two minerals from an ore are concentrated together in the froth, depressants may be used to restrict the flotation of one of them. A depressant for any mineral is a substance (generally inorganic), the addition of which prevents a collector from functioning as such for 6 that mineral. !Eheir action should he specific and their concentration in the pulp must he closely governed, because an excess may cause com­ plete depression of the minerals. are: Some of the commonly used depressants sodium silicate, sodium cyanide, sodium carbonate, sodium bicar­ bonate, sodium pyrophosphate, tartaric acid, citric acid, etc. Gaudin^^ states that the optimum quantities of the reagents to be used in froth flotation cannot be predicted, but that depends on such a variety of circumstances as to defy classification. However, the following points may be useful. (1) Increasing the fineness of grinding requires an increase of all reagents except frothers which may or may not have to be decreased. (2) Use of thick pulps result in some economy of the reagents. (3) Desliming the ore may permit a considerable reduction in the quantity of reagents of the type which are active at the mineral surface. (4) Changes in type of flotation machine may require some adjustment in the quantity of the reagents. The same is likewise true for changes in place or time or physical method of addition. A word of explanation might be added here, with regard to a few of the other terms used in this investigation. charge into the flotation cell. HEADS refers to the CONCENTRATE refers to the material collected in the overflow, and the solids remaining in the liquid are called the TAILS. The percentage recovery refers to the fraction of the total mineral in the heads that is present in the concentrate. 7 PREVIOUS WORK OH CASSITERITE The investigation on the flotation of cassiterite "began as early as 1920 , when Edser^ used the following flotation method and reagents* He took a sample of black Nigerian cassiterite and mixed it with white quartz gangue. He used a small amount of sodium oleate solution to­ gether with an alkaline gangue modifying reagent* culty observed by him in flotation. There was no diffi­ He obtained 90 percent recovery. In 1927, A. C. Vivian^ obtained as high as 90 percent recovery using 0.10 pound per ton of cupferron as a collector; and coal tar and creosote as the frothing agents* In 1939, 0. C. Ralston^ used oleic acid, linseed oil, and fish oil as the collectors; and tar oil, anthracene oil, and crude cresol as the frothers; and obtained 97 percent recovery. At the same time, Handy and Beard^ reported the use of soaps as the collectors. In 19^1, Oberbillig and Frink^ reported the use of oleic acid, palmitic acid and sodium oleate as collectors; and sodium hydroxide, and sodium carbonate as depressing agents. It was found that the above two inorganic chemicals showed greater depressing effect at higher con­ centrations but at lower concentrations they were not so powerful. They also reported the use of sodium silicate and tannin as powerful depressants for cassiterite. At lower concentrations ferric chloride, lead acetate and silver nitrate showed good depressing quality. In 19^1, Brown^ added oleum, cresote, (a crude blast furnace grade) pine oil, and potassium amyl xanthate respectively in the flotation of cassiterite and obtained satisfactory results. 8 In 19^-, Sean and Ambrose^ reported that according to French Pat­ ent 755 ,895 , a mixture of sodium oleate and the sodium salt of the butyl ester of ricinoleic acid is effective in the cassiterite flotation. Two hundred grams of sodium oleate, and 200 grams of the sodium salt of the ricinoleic acid per ton gave 99*7 percent recovery, with 35 times enrichment. They also reported the successful flotation of cassi­ terite with the use of 0.25 pound sodium oleate, 0.10 pound Ninol ^31 * and 1 pound of oleic acid per ton. Frother 4o (du Pont) could be sub­ stituted for Hinol ^31 with slightly inferior results. Gaudin et al 21 reported the satisfactory use of sodium oleate as a collector in the presence of a frothing agent# oleate used was 0.20 pound per ton. The amount of sodium It was also reported that six pounds of heptylic acid or one pound of nonylic acid per ton is required to obtain complete recovery of pure cassiterite. Cassiterite had a tendency to float before quartz, when these reagents were used, perhaps, due to the relative higher adsorption of the fatty acids. Better sep­ aration was obtained by increasing the amount of the reagents. Thirty hundredths pound per ton of cupferron was also used in a neutral cir­ cuit in the presence of 0.50 pound per ton of terpineol as the frothing agent. , 19 In 19^6, Gaudin et al discovered oleic acid, saturated long chained fatty acids, lauryl pyridinium iodide, lauryl amine, and lauryl amine hydrochloride to be very good flotation reagents, a n d ^ hydro­ carbon oil such as Nujol as useful collecting agents. were obtained with smaller particle size (325 mesh). Better results Sodium cyanide, 9 sodium silicate were used as the modifying agents. range was found to he 6.75 to 7.10. In 194-7 » Hergst et al Satisfactory pH Pi advanced the idea that a polar group like •S a -S0i| , or -SOtj was needed in a reagent for it to be an excellent tin collector. They stated that pH up to 9 was quite satisfactory, but pH below 5 gave less recovery. They presented no data supporting this view, nor has any such data been found in the literature of cassiterite flotation. In 1950» Graham, Thomson*^ concluded that the typical non-polar structure like that of parrafin chain salts was needed in collectors for the flotation of cassiterite. E X P E R I M E N T A L W O R K DESIGN OF THE COLLECTOR In designing the collector for the flotation of cassiterite, consideration was first given to the general physical and the chemical properties of the mineral. The specific gravity of the cassiterite i s 7.3 grams per cubic centimeter, while that of silica is 2 .3 grams per cubic centimeter. Large particles of cassiterite and silica are readily amenable to gravity separation. is indicated when the particles are fine. However, flotation separation It is with the latter size material that this presentation is actually concerned. On the basis of the article by Hergt, Rogers, and Sutherland, 26 reagents containing either -SOi|” or S0 ^“* are excellent collectors, these investigators present no data to support their conclusions. It was found that the use of 4 alkyl 2 sodium benzene sulfonate was later g patented by Commonwealth Council • There seems to be no connection 26 between the previous paper and this patent. Gaudin and Sun stated that hydrated hydrogen, hydroxyl, and sulfate ions fit particularly well into the continuation of cassiterite lattice, the oxygen of these various ions has the same dimensions as the dxygen ion of the cassiterite. Otto, Neunhoeffer^ suggested that a compound containing a phenyl radical with a nitro group in ortho, and methyl group in para positions would be the best for this work. used the xanthates of the above in his investigation. He From these two ideas it was concluded that a compound named 2-Nitro U alkyl phenol might also serve as a collector. The problem was thus resolved into a 12 study of 2 Nitro resorcinol ethers and the 2 Nitro ^ alhyl phenols as flotation collectors for cassiterite. The substituted alfcyl groups for each series were n-hexyl, n-oetyl and n-decyl. FLOTATION MACHINE The flotation edll used for this investigation was a laboratory size sub-aeration type cell, made of lucite; whose details are shown in Figures 1 and 2. The agitator was driven through a V-belt from an electric motor, step pulleys made possible variation in the agitator speed. Froth overflowed from the cell into a Buchner funnel, the fil­ trate from the Buchner funnel was conducted to the suction bottle con­ nected to a small vacuum pump, the suction bottle was so arranged that by cutting off the vacuum, it was possible to drain the filtrate into the feed bottle. Liquid contained in the feed bottle was fed into the cell during a run to maintain constant pulp level. Air was supplied to the bottom inlet of the cell from a low pressure blower. Reagents were added to the cell from a special titrating burette, having a long curved tip which made it possible to introduce the reagents well below the actual liquid surface, into the zone where they would be promptly dispersed into the pulp. PARTICLE SIZE Pf) Gaudin, Groth, and Henderson state that the usual particle size for flotation of any mineral varies between 50 and 100 microns. corresponds to about 150 to 300 mesh. This For this investigation minus 1*5 -120 - mesh was used because Gaudin J states that for cassiterite, 13 expressed A/r Lucife Ce// y&ei/ttjn FIGURE * /CO &*. tt-OTAT/OA/ CjELL 14 FLOTATION CELL Fig. Si 15 particle size below 100 mesh gives less recovery. It is also stated that when the particle size is reduced below 5 microns, a slime is formed, which does not respond to flotation action. While this theory lacks complete confirmation^® removal of the slime particles is gen­ erally good flotation practice* PULP DENSITY An increase in the apparent density of the pulp causes particles to rise to the surface more easily. Thus a higher concentration of the minerals in the suspension tends to aid flotation; but it also increases harmful effect of slime. The usual amount of solids in the pulp varies from 20 to 30 percent for optimum condition. In this investigation 25 percent solids were used* ADDITION OF REAGENTS Reagents were added to the pulp in the following order: Collector and Depressing agent or Activator. Frother, Excess addition of the collectors and frothers was avoided* Dean and Ambrose^ show that a conditioning period for certain cationic agents may seriously decrease the extent of flotation. The reagent is more effective immediately after addition than any other time. Their data show that 90 percent yield may be decreased to 10 percent by an eight minute conditioning period before flotation. In this investigation a conditioning period of five minutes was allowed for each run before adding any reagents, but after adding the 16 reagents no conditioning period was allowed. Collection of the froth followed immediately after the reagent addition. The cassiterite and silica sand were diy ground in a one foot by one foot Abbe porcelain ball mill; pebbles were used as the grinding medium* The ground materials were separated using Tyler standard sieves which pass minus -120 - mesh. overgrinding of the materials. Proper care was taken to avoid In preparing a synthetic mixture the appropriate quantities of the ground cassiterite and silica sand were added separately to the cell and mixed therein. The total charge in the cell was 100 grams of solids and 300 grams of water for each run* The frother used in all the runs was steam distilled pine oil* It was added in small quantity as required. Not more than 0*2 pound per ton of solids was used* The collectors tested were made up as alcoholic solutions, 0.0005 grams of the chemical per milliliter of the solution. Reagents used for adjusting pH were C.P* hydrochloric acid, and C*P. potassium hydroxide, both as 5 percent solutions* All the pH measurements were made using Hydrion test papers from a set of narrow range papers providing at least two checks on any single pH figure* EXPERIMENTAL PROCEDURE In most of the following flotation tests only a frother, a col­ lector and the pH adjusting agents were used* Approximately 70 millili­ ters of water, the pH of which was adjusted to that specified for run were placed into a feed bottle* turned on. The agitator, air and the vacuum were The water and the samples were introduced into the clean 17 cell, in such quantities as to leave a space of 5 for frothing blanket* 10 milliliters The pH was adjusted at once to that desired. A conditioning period of five minutes was then allowed, at the end of which one small drop of pine oil was added. When the froth was rees­ tablished, the collector was added at a regular dosage every minute from the dispensing burette for six to ten minutes of period as desired. The froth for this period was collected on a medium filter paper in the Buchner funnel. Water was drained from the funnel by vacuum filtration, and the froth was removed to evaporating dish, and dried at 115°C. tailings from the cell were removed and the cell was well washed. was determined by the volumetric method of Pearce-Lource. The Tin Volumetric determination of Tin. One gram of froth (dry basis) was weighed exactly, and was taken into a nickel crucible. To this was added three grams of sodium car­ bonate and both were mixed well. This mixture was then covered by the addition of seven grams of sodium peroxide, and fused and allowed to cool. The crucible with the fused content was placed into a beaker and the content was taken up with 50 milliliters of water and 100 milli­ liters of concentrated hydrochloric acid. The solution was transferred to a flask and a nickel coil, was introduced. The solution was boiled for 30 minutes, to reduce iron, the reduction was indicated by a color change from yellow to green. The solution in the flask was cooled; a carbon dioxide atmosphere was maintained by the addition of sodium car­ bonate. The nickel coil was washed with an acid solution and removed. With the temperature of the solution below 22°C., tin was determined by titrating the solution with standard 0 .10N iodine using starch as the indicator. D A T A AND R E S U L T S 18 TABLE 1 FLOTATION OF CASSITERITE BY NAP-10 (Figures 3-6,7,13-16,17,23,24) Synthetic ore: 98 grams sand and 2 grams cassiterite Tin in synthetic ore: 0,032 percent Time of run of experiments: 6 minutes Synthetic ore size: minus 120 mesh pH Collector Concentrate Lbs. per ^ Enrich- Percent Ton gras. Tin ment Recovery Derived Lbs. Tin per lb. Collector Data Improvement Factor 3 .2 12.586 .200 6.26 80.5 2.56 504 6 .2 8.585 .374 11.70 99.7 3.22 1166 9 .2 9.58 .300 9.38 89.7 2.87 850 12 .2 9.145 .200 6.25 57.2 1.82 357 3 .1 9.37 .374 9.37 87.6 7.00 822 6 .1 8.075 .398 12.40 99.6 6.37 1235 9 .1 5.46 .450 14.05 76.5 4.91 1075 12 .1 8.57 .300 9.38 80.5 5.14 755 3 •06 9.11 .200 6.25 57.0 6.08 356 6 .06 9.154 .300 9.38 85.8 9.15 806 9 .06 6.87 .351 10.94 75.2 8.05 823 12 .06 7.7 .200 6.26 48.2 5.13 302 3 .03 10.285 .050 1.56 16.05 3.42 25 6 .03 7.58 .415 12.94 82.8 21.0 1073 9 .03 7.42 .351 10.94 81.2 15.05 890 12 *03 8.86 .250 7.82 69.2 14.75 541 19 TABLE 2. FLOTATION OF CASSITERITE BY NAP-8 (Figures 3-6,8,13-16,18,23,24) Synthetic ore: 98 grams sand and 2 grams cassiterite Tin in synthetic ore: 0.032 percent Time of run of experiments: 6 minutes Synthetic ore size: minus 120 mesh pH Collector Concentrate Lbs. per Jo Enrich-Percent ment Recovery Ton gms. Tin .2 6 .2 9 8.643 47.4 1.51 259 14.68 .175 5.47 80.0 2.57 438 .2 7.0 87.5 2.82 1096 12 .2 13.6 3 .1 6 CVJ 5.47 • .175 o 3 Derived Data Lbs. Tin Improveper l b . ment Collector Fac‘ 12.50 .200 6.25 85.0 2.72 532 6.22 .450 14.05 87.5 5.60 1230 .1 9.22 .300 9.37 86.2 5.53 807 9 .1 8.05 .350 10.94 87.2 5.63 955 12 .1 13.73 .200 6.25 86,0 5.50 538 3 .06 8.175 .250 7.8 63.8 6.82 497 6 .06 6.31 .350 10.94 69.0 7.36 755 9 .06 4.405 .450 14.05 61.8 6.61 890 12 .06 4.8 .374 11.7 56.2 5.98 658 3 .03 6.75 .402 12.5 84.5 18.10 1060 6 .03 5.096 .200 6.25 31.8 6.80 198 9 .03 5.45 .350 10.94 -59.5 12.70 653 12 .03 5.025 .350 10.94 55.0 11.70 603 20 TABLE 3 FLOTATION OF CASSITERITE BY NAP-6 (Figures 3-6,9,13-16,19,23,24) Synthetic ore: 98 grams sand and 2 grams. cassiterite Tin in synthetic ore: 0.032 percent Time of run of experiments: 6 minutes Synthetic ore size: minus 120 mesh pH Collector Concentrate Enrich­ Percent Lbs. per % ment Recovery Ton gms. Tin Derived Lbs. Tin per lb. Collector Data Improve­ ment Factor 5 .2 10.785 .175 5.47 59.0 1.88 323 7 .2 11.245 .250 7.81 87.8 2.81 684 10 .2 6.97 .300 9.37 65.3 2.09 613 5 .1 9.32 .200 6.25 58.3 3.73 364 7 .1 11.685 .225 7.02 82.1 5.26 576 10 .1 9.95 .200 6.25 62.2 3.98 384 5 .06 9.145 .200 6.25 57.2 6.2 357 7 .06 9.75 .200 6.25 60.9 6.5 381 10 .06 9.31 .225 7.03 51.4 6.98 361 5 .03 8.655 .150 4.68 40.6 8.65 190 7 .03 8.77 .150 4.68 41.2 8.77 193 10 .03 5.16 .250 7.81 40.3 8.60 314 21 TABLE 4 FLOTATION OF CASSITERITE BY NRE-10 (Figures 3-6,10,13-16,20,25,26) Synthetic ore: 98 grams sand and 2 grams cassiterite Tin in synthetic ore: 0.032 percent Time of run of experiments: 6 minutes Synthetic ore size: minus 120 mesh Collector Concentrate Lbs. per Jo Enrich- Percent Ton gms. Tin ment Recovery .2 8.19 7 .2 11.692 10 .2 9.50 5 .1 8.512 7 .1 10.15 83.2 2.66 845 8.42 98.5 3.15 850 .300 9.37 89.0 2.85 835 10.15 86.4 5.14 870 9.045 .325 10.15 91.4 5.88 930 11.075 .252 7.82 86.2 5.14 673 8.445 .275 8.60 72.5 7.72 623 8.90 92.5 9.87 823 11.94 85.2 9.92 1020 .325 • COJ • 10 Derived Data Lbs. Tin Improveper lb. ment Collector Factor o 5 UJ TO pH 5 .06 7 .06 10.40 10 .06 7.78 5 .03 7.155 .300 9.38 67.0 14.3 628 7 .03 8.635 .300 9.38 81.0 17.25 760 .03 7.435 .325 10.15 75.4 16.10 767 K\ CO rA * 1 0 .285 22 TABLE 5 FLOTATION OF CASSITERITE BY NRE-8 (Figures 3-6,11,13-16,21,25 ,26) Synthetic ore: 98 grams sand and 2 grams cassiterite Tin in synthetic ore: 0.032 percent Time of run of experiments: 6 minutes Synthetic ore size: minus 120 mesh pH Collector Concentrate Lbs. per % Enrich­ Percent Recovery Ton gms. Tin ment DERIVED DATA Lbs. Tin Improve­ per lb. ment Collector Factor .2 8.44 .305 9.39 79.2 2.57 745 7 .2 7.865 .374 11.70 92.3 2.94 1083 10 .2 6.08 .350 10.94 66.5 2.13 727 5 .1 9.5 .200 6.25 59.4 3.80 371 7 .1 9.7 65 .250 7.80 76.2 4.88 594 10 .1 10.61 .150 4.70 49.8 3*18 234 3.59 476 .06 7.0 .1535 61.0 7 .06 8.90 .1535> 7.80 69.6 4.65 542 10 .06 7.40 .300 9.38 69.3 7.40 650 5 .03 8.055 .250 7.81 62.8 13.40 490 7 .03 8.51 .260 8.13 69.0 14.75 562 10 .03 5.8 .250 7.81 45.3 9.66 354 • 5 0 00 5 23 TABLE 6 FLOTATION OF CASSITERITE BY NRE-6 (Figutes 3-6,12,137l6,22,25,26) Synthetic ore: 98 grams sand and 2 grams cassiterite Tin in synthetic ore: 0.032 percent Time of run of experiments: 6 minutes Synthetic ore size: minus 120 mesh pH Collector Lbs. per Ton Concentrate gms. Tin Enriehm'R&reent ffient Recovery Derived Data Lbs. Tin Iraproveper lb. ment Collector Factor 5 .2 10.235 .250 7.82 80.0 2.56 626 7 .2 8.20 .300 9.38 76.7 2.46 720 10 .2 6.315 .225 7.03 44.3 1.42 311 5 .1 9.40 .275 8.60 80.7 5.17 702 7 .1 6.875 .350 10.94 75.3 4.82 826 10 .1 6.25 .250 7,81 48.7 3.12 381 5 .06 7.435 .372 11.60 87.0 9.20 1010 7 .06 5.86 .300 9.38 55.0 5.86 515 10 .06 3.875 .300 9.38 36.3 3.87 350 5 .03 6.485 .150 4.69 30.4 6.48 143 7 .03 5.52 .200 6.25 34.5 7.38 216 10 .03 4.365 .200 6.25 27.3 5.55 171 24 TABLE 7 FLOTATION OF CASSITERITE BY NAP-10 AND NRE-10 In this table the effect on final concentration Is shown by increasing the original percent of tin in the synthetic ore. Time of run of experiments: 6 minutes Synthetic ore size: minus 120 mesh Collector % Tin in Na2SiO^ Concentrate Type Lbs.per synthetic EnrichTon mixture #/Ton gms. ment Percent Recovery o HI• None 8.13 11.25 91.5 • H O PH None 8.64 11.50 99.3 .953 None 41.275 1.84 76.0 .20 .953 None 34.575 2.47 85.2 NAP-10 .20 .10 None 4.50 18.00 81.0 7 NAP-10 .20 .10 None 7.08 14.0 99.2 5 NAP-10 .20 .953 None 29.90 1.416 42.3 7 NAP-10 o CVl • .953 None 38.80 2.44 94.7 5 NAP-10 .20 .953 1 11.71 2.52 29.5 7 NAP-10 .20 .953 1 18.615 2.36 44.0 7 NAP-10 .2 18.20 2.25 41.0 7 NAP-10 o o OJ OJ • • .953 .953 .5 25.44 2.52 63.7 7 NAP-10 .20 1.60 .75 16.10 4.67 75.3 7 NAP-10 .20 1.60 .75 15.70 4.72 74.2 5 NRE-10 .20 7 NRE-10 .20) 5 NRE-10 .20 7 NRE-10 5 25 TABLE 8 In this table, the Bolivian ore and the black ore of high percent tin is used. Time of ruh of experiments: 6 minutes Synthetic ore size: minus 120 mesh Collector used: .20 pound per ton FLOTATION OF CASSITERITE BY NAP-10 pH Type of % Tin in Ore mixture NaoSiO-, #/Ton ^ Concentrate gms. Enrichment Percent Recovery 5 Bolivian .44 1 8.53 2.90 24.74 7 Bolivian .44 1 10.10 2.40 24.24 7 Black 13*20 None 17.84 3.70 66.00 7 Black 13* 20 None 16.10 4.47 73.20 26 vo r-i -5fr~f OJ r-1 o VO CO OJ O rH OJ CO OS X exX 3 - o vo o LO o o KV o OJ o rH Figure o +3 ro o vo a> 30 vo r-l :cvi H 1o «-4 iU3 JC.I8A O O 0H <& OJ rH VO o m o o C?\ o 00 o c^- o vo o o o tn o OJ o rH Lb.collector/Ton Figure 8 NAP-8 'O o feed OJ 32 i—i OJ H O GO vo OJ rH ^uanrqoTJ^t3 A*i9Aooay % Figure N AP-6 vo -4 - OJ O CO V O ^ - C U O rH VO O C HRE-10 VO ^.uamtro jjtu^ AJqa o o s h % vo o CO o c* o vo o o o 34 vo rH i—! OJ i—I o H CO VO OJ vo o KV O gusonroTJUfl /!sI9 A 0 0 9 H % OJ rH VO O O o o\ o CO o d- o vo o O o OJ o rH Lb.collector per Ton feed Figure 11 OJ 35 'O fH -cj- i—I CM i—| O OJ CO OJ o OJ T.xi9urq;0TJru3 XJ9A003>TX o -H OJ O 'O D O o\ a CO o t- o \o o o O OJ O H 36 o o O O O O o o O C VO OJ CO O -d’ xd __ -- cd-- _cd___ ed__ __ e4 o cu rH On K Q, txo^ovj q.U0oi9AOJ[ciraj trrt ‘flirt a o ^ d ^ T W ‘qt 5 CO rH VO H H OJ rH O rH CO MD Figure 13 .2 lb.collector per ton feed VO 37 o 00 o o CXI j=± o o o o CO o OJ o r—i I—I ton feed ON VO Figure 14 .1 lb.collector per 00 aoq.o^i[ %u9Ui9A0jdmi joaoonoo *qx asci uia*qq iH VO On 03 CO VO 38 o o 00 o o vo Q 3 o o OJ o o o o o CO o o o o vo o o OJ CO Figure 15 .06 lb.per ton feed JC ft luamoAOjdrTji ao ^ o a x i o o * q i .19d u T X ' q q oo rH f-r oo <— I ON ft oo vo co 39 o GO rH i—I i—I rH cu vo CD o\ i— 1 00 q.uaraaAOtidmx Ejo^oartoo 'gq/tiTi -qq CO VO 00 O CO 1—I rH -P vo © HH © o o o o o CO iH o VO rH ->fr fH O O CO O O O rH O O OJ H O o o o s 40 o o Cu KQ CD o aoq.o'Bj q.u9niSA0jdnrx j o ^ o s x i o o *q x jrad u T ^ ' S c n & cu *4 VQ o O O c H q v rH o - H ^ C H M H O cO v o ^j- c v j O 41 o o CO o o VO -C=|-- --<=d-- O O o O OJ ni__--C=1-- O o o r-i O o 00 o o VO o o --f o o OJ OJ o O o o jo'j.o'eg q.usraaAOJcdini “JO'i'j a i i u ’ o •q i , jyd ttt ; ’sqr OJ Q\ VO O o o o —I CO H VO -=t i —I O J o fH CO VO OJ o Lb.oolleotor/Ton Figure 18 NAP-8 VO feed Vi) 1800 o o VO 1—1 o o -cfrH O o OJ rH O o o O o CO O O \o o o -cf o o OJ 42 o rH OJ O CD quaniSAOjduix j:oq.oaiioo *qi jcact an. *sqq OJ VO o o o o CO VO fH OJ H o rH QO VO OJ o o 43 o o 00 rH O O VO rH o o H O O OJ rH o o o o o O O CO VO o o -3' o o OJ H o OJ m VO 0 ’ ^ Increase in collector concentration does increase the recovery and enrichment. In this investigation it was found that by using longer chain length, collector concentration as low as 0.03 pound per ton was quite satisfactory, while by using shorter chain length collector con­ centration as high as 0.10 pound per ton was required. The isometric three dimensional representation of this investiga­ tion is shown at the end of this thesis in a pocket; which gives better picture of this investigation. C O N C L U S I O N 55 CONCLUSION The following conclusions are drawn from the data presented* (l) It is shown that Nitro alkyl phenols and Nitro monoalkyl resorcinol ethers function as collectors for cassiterite in the synthetic mixture of cassiterite with silica sand* ?2) It is shown that these collectors are specific for pure and concen­ trated ores in presence of depressing agent like sodium silicate. (3) It is shown that pH, collector concentration, and the length of carbon atom chain affect in varying degrees the flotation of cassiterite* (*0 Both series of the collectors are equally good, and easily pre­ pared from commercially available raw materials. (5) Variation of pH from six to nine gave satisfactory results in this investigation. (6) pH seven is most desirable. Recovery as high as 99-7 percent was obtained. Enrichment as high as 14 times was obtained using synthetic mixture of cassiterite and silica sand. A P P E N D I X 57 GENERAL DISCUSSION The following two series of the organic compounds were prepared for this investigation: (1) 2 - Nitro 4 alkyl phenols, (2) 2 - Nitro resorcinol ethers* There are several methods for preparing these chemicals, hut the easiest and the one which gives high recovery was selected for each series. For use as a flotation agent, a predetermined structure is desired hut branch chain is not necessary. SYNTHESIS OF 2 - NITRO RESORCINOL ETHERS The complete reaction for preparing 2 - Nitro resorcinol ethers can he given by the following two steps: OH (1) 0 OH oH + na _ OH (2) f j K y oR HCl OH ( %■ + HUO, ----»] 3 5-10° 0 . \/oft HoO 2 In the above reactions R can be n-hexyl or n-decyl n-octyl (CgH^j), group. The resorcinol monoalkyl ethers were prepared according to Kharman, G-hatyas and Shternow.-^ One mole of resorcinol (119 grams) was dissolved in 225 milli­ liters of absolute ethyl alcohol, in a one liter flask provided with an air tight stirrer, a reflux condenser, and a dropping funnel. One 58 mole of n-octyl chloride (150 grams) was added and the mixture was heated to refluxing. Then one mole of potassium hydroxide (5b.l grams) in l6S milliliters of water, was added slowly over a period of about three hours* Separation was affected by a simple extraction method as discussed below. Water was added to the cooled mixture which was placed in a sep­ aratory funnel. Then there was added 750 milliliters of diethyl ether followed by hOO milliliters ©f tion, 6 N sulfuric acid to insure acid extrac­ A copious precipitate of potassium sulfate was formed. The two liquid layers were separated from the funnel, and the acid layer was again extracted with 250 milliliters of diethyl ether. The combined ether extract was washed repeatedly with cold water until no reaction was given with ferric chloride solution. plete removal of the unreacted resorcinol. This was a test for the com­ The etherial layer was extracted repeatedly with 5 percent sodium hydroxide solution. The alkaline extract was shaken with ether, the washed alkali was acidi­ fied with 50 milliliters of 6 N hydrochloric acid. was shaken out again with pure ether. The separated oil The evaporation of the ether gave about 25 milliters of heavy red oil. Distillation of this material through a fifteen centimeter open fractionating column with an adiabatic jacket gave 20 milliliters (1 U .5 grams) of clear red product. A similar procedure was used for decyl and hexyl resorcinol ethers. n-Decyl chloride, n-octyl chloride and n-hexyl chloride were prepared by the method given in organic synthesis, Coll. Vol. 1 octyl bromidds. 29 J for normal 59 The following are some of the physical properties of these com­ pounds: No. Compound B.P. Yield 1 Hexyl resorcinol ether lU0-150°C (5 mm.) 2 Decyl resorcinol ether l60-l65°C (5 ™a*) 3 Octyl resorcinol ether 155-158°C (5 mm.) 21$ Colour Light yellow &ed 7$ For preparing the nitro compounds from the above ethers the procedure followed was that of Cecil M. Galloway. 0.17 mole of octyl resorcinol ether was dissolved in SO milli­ liters of benzene; and the dissolved mixture was taken into a dropping funnel. 0.18 mole of nitric acid with 12 ml. of water was placed in a three necked flask fitted with a reflux condenser, an air tight stirrer, and a dropping funnel. © ing down to 8 C. The acid mixture was cooled by an external cool- The mechanical stirrer was then started, and the octyl resorcinol ether solution was added dropwise from the funnel, maintaining the temperature of the mixture at 5-10°C« After completing the addition of the octyl ether from the funnel, the reaction mixture was stirred for half an hour. The reaction mixture was diluted with water and the benzene layer was separated* distillation. The bezene was separated by The residue was vacuum distilled* The same procedure was followed for hexyl and decyl resorcinol ethers to obtain nitro compounds. high as 80 percent. The recovery in this step was as 60 SYNTHESIS 01 2 NITRO k ALKYL PHENOLS The reactions involved are as follows: t^h3 (1) (Jj OCHj + RC0C1 Q CO w c?H OCMjj (2) j^J + HBr -------- Q co + CH^Br SP * OH * OH (3) (^) + HG1 + NH2NH2 + N 2 + HgO ---- ► C1O R OH W 0 + “ °3 5^ o5 T >? 0 U + H2° * Anisole ketone was prepared according to Pieser and Hershberg. 11 In a three necked flask fitted with a mechanical stirrer, a reflux condenser and a thermometer; one mole of anisole (108 grams), 600 milliliters of tetrachloroethane as a solvent and 1 .2 moles of hexanoyl chloride (l6l grams) were placed, and cooled to 5°C by an external cooling by ice salt mixture* The mechanical stirrer was started, and 1.^ moles of anhydrous aluminum chloride (187 grams) were added gradually over a period of three hours. It was allowed to stir for half an hour more, maintaining the reaction temperature ^4—3°C. The red reaction mixture was allowed to stand for three days at room temperature. 6i The fatty acid chlorides were prepared according to the method of Armour Chemical Company. 2 The reacting mixture after three days was poured into a four liter beaker containing hydrochloric acid and cracked ice. Brownish precipi­ tate separated out when the mixture was allowed to stand for a few hours. The tetrachloroethane layer was separated and was extracted with 1200 milliters of diethyl ether. The ether extract was treated with concentrated sodium carbonate solution. The ether extract was distilled to boil off the ether, tetrachloroethane and unreacted anisole. The residue was treated with hydrobromic acid^^ as follows: In a three necked flask fitted with a stirrer, a reflux condenser and a thermometer, the above residue was taken and to this was added one mole of US percent hydrobromic acid. The mixture was allowed to reflux by external heating, and stirring begun. to go for three hours. The reaction was allowed Next day, the excess hydrobromic acid was re- moved, and the residue subjected to the VITolfe-Kishner reduction. 36 In a three liter, three-necked flask, the above residue was placed with 1500 milliliters of diethylene glycol; 190 grams of potassium hydroxide and 130 milliliters of 85 percent hydrazine hydrate. A thermometer, a mechanical stirrer and a take off condenser were joined to the flask. The mixture was allowed to reflux for one and one half hours and then the water was drained off, by the take-off condenser until the temperature of the reaction mixture reached 195°C. Then it was allowed to reflux for four hours longer, and allowed to stand over­ night. 62 The above reaction mixture was acidified by adding concentrated hydrochloric acid and extracted with 2000 milliliters of benzene. The benzene was evaporated out, and the residue was vacuum distilled. The same procedure was followed for preparing 4 octyl phenol and 4 decyl phenol. The boiling points of these alkyl phenols are given below* No. Compound B.P. Pressure 1 4 hexyl phenol 118-122°C 4-5 mm. 2 4 octyl phenol 130-l4o°C 6-8 mm* 3 4-decyl l46-150°C 6-8 mm* phenol The nitration of these compounds was carried out according to Cecil M. Galloway 13 , as described for resorcinol ethers. The physical properties of the nitro compounds are as follows: No. Compound B.P. Pressure Yield 1 2 Nitro 4 hexyl phenol l42-46°C 15 mm. 50$ 2 2 Nitro 4 octyl phenol 152-55°C 15 55$ 3 2 Nitro 4 decyl phenol l60-62°C 15 mm. 52$ B I B L I O G R A P H Y 6 * + BIBLIOGRAPHY British Patent 292,632 (April 3,1928). 1 Anthoine, R . , and Blarney, R* 2 Armour chemical company. Preparation and Analysis of Patty Acid Chlorides, Tech. Ing. Bull. Ho. 4a. (Sept. 29 , 1948). 3 Bishop, W. T., 4 Bragg, W. L. Atomic Structure of Minerals, Cornell University Press, (1937)• 5 Brown, L. 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Pub. 2826B, 18£, 591-600 (1950). Mining Engineering, Tech* HH Schuhmann, R., Jr., and Prakash, Brahm. Pub* 2827B, 188, (1951)* Mining Engineering, Tech* H5 Spedden, H. Rush, and Hannah, William S., Jr. (March 19H8)* H6 Sulman, H. I. U7 Taggart, A. A. Handbook of Mineral Dressing. John Wiley and Sons, Hew York, (l9H5y7 U8 Taggart, A. A., Taylor, T. C., and Knoll, A. F. Min. and Met., 81, 219, (1930). H9 Vivian, A. C. 50 Wark, I. W. Principles of Flotation, Australian Inst. Min. and Met., Melbourne, (19387** Mining Tech.. 12. U. S. Patent 955,012, (April 12,1910). Trans. Am. Inst. Mining Magazine, j>6 , 3^8-351* (1927)* IMPROVEMENT FACTOR * T I N / w COLLECTOR FIG. 24 400 NAP-IO 200 .06 3 *03 600 400 N A P -8 •06 .06 3 .03 6 N AP-6 200 3 0 0 ^COLLECTOR / TON '^COLLECTOR/TON o b- LIBRARY an S T A T E U N I V E R S I T Y L A N S I N 3 . M I C H IG A N IMPROVEMENT FACTOR *T IN /# C O L L E C T O R FIG- 2 6 600 NRE-IO 200 •06 03 200 0 •06 .06 5.03 5 .03 N R E -6 ^ < 0 6 0 3 ^COLLECTOR / TON ^C OLLE C TO R / T O N ENRICHMENT % RECOVERY FIG. 2 5 60 N R E - IO 40 20 .06 5 -03 N R E -8 40 20 .06 NRE-6 20 06 03 ^C O L LE C TO R /T O N 06 5 -03 ^ C O L L E C T O R /T O N ENRICHMENT X RECOVERY 40 NAP- 8 20 .06 03 N A P -6 20 06 5 .03 ^ C O L L E C T O R /T O N .06 # C O L LE C TO R /TO N