Патент USA US2125337код для вставки
2,125,337 Patented Aug. 2, 1938 UNITED STATES PATENT ,OFFICE 2,125,337 FLOTATION REAGENTS AND LIETHOD OF USE Antoine M. Gaudin, Butte, Mont. No Drawing. Application December 24, 1929, ' Serial No. 416,291 5 Claims. (01. 209-166)‘ As an illustration of the depressing effect of This invention relates to the recovery of values from ores by subjecting the same to a ?otation mercaptans upon iron minerals as compared with the xanthates, a ?otation operation con operation in the presence of certain reagents. I have discovered that certain organic sub - ducted in a circuit containing pure pyrite in the 5 stances of the general formula RSH (in which R presence of 0.05 lb.- per ton of potassium ethyl denotes a hydro-carbon radical, S-sulphur, and xanthate, recovered the entire amount of the iron. Using the same amount of thio-beta-naph I-I—hydrogen), such as mercaptans and thio thol a concentrate was obtained which contained phenols, are particularly good collectors of cop per minerals, oxidized aswell as sulphides, as 97% of the iron. When pure chalcolcite was sub jected to a ?otation operation under the same 10 10'- well as of the sulphides of zinc. Likewise the ox circumstances with the above, two reagents the idation products of these organic hydro-sul phides such as the sulphides and di-sulphides recovery was 62% and 96% respectively. In the are substantially as good collectors as the mer same manner the recoveries of these minerals - captans themselves for the. sulphide minerals with 0.03 lb. per ton of potassium ethyl xanthate and isoamyl mercaptan, is respectively 93% and 16 86% for the pyrite and 57% and 92% for the chalcolcite. Similarly, in synthetic mixtures of pyrite and chalcolcite, xanthate favors the recovery of py rite, while mercaptans favor the recovery of the 20 copper mineral. Upon mixtures consisting of 25 grams of minus 200 and plus 400 mesh pure py-' only. 15 The use of these reagents in the recovery of minerals by ?otation is of particular advantage in that they are not good collectors for iron sul phides such as pyrite or'pyrrhotite, and hence their use on pyritic copper ores is particularly valuable in that they collect the copper minerals to the more complete exclusion of the iron min erals than is obtained through the use of other collectors, of which the xanthates are typical. The ability of mercaptans to collect oxidized 25 copper minerals makes the recovery of the ox rite, and 25 grams of the same size pure chal colcite, the following recoveries were obtained with amyl xanthate and amyl mercaptan, each used in the amount of .03 lb. per ton. idized content of sulphide ores more ei?cient since from 1/3 to 3/; of the total copper loss in sulphide copper ores by ?otation is due to their oxidized content. 30 Pyrite re Reagent covery Chalcolcite - recovery _ ' The mercaptans require less alkaline circuits than the xanthates for the securing of conditions 98 Amyl mercaptan- ................ __'.___- 82 30 Percent ' Percent Amy] xanthate ___________________________ - 96 ‘ which result in the depression of iron minerals and therefore the use of the former in place of xanthates effects economies~ in the use-of lime or ‘ea in corresponding alkali. . The higher alkyl mercaptans, that is, those in the series higher than ethyl mercaptan, to wit, propyl, butyl, amyl, hexyl, heptyl, octyl, are of particular advantage because of their greater 40 collecting ability and their lesser volatility as compared to the mercaptans lower in series. The lesser volatility is of prime importance from a practical standpoint because it lessens the dis comfort caused by the semi-poisonous vapors and loss of reagent. ‘ - ._ I have discovered that the oxidation products The pyrite which occurs in ores is generally substantially less ?oatable than the pure pyrite 35 used in the above tests. This is probably due to the presence of oxidized coatings on- its surface. The absolute values obtained in tests with ores are therefore not in agreement with those ob tained with pure minerals, but the relatively 40 greater ?oatability of pyrite with xanthate and ohalcolcite with mercaptan again manifests itself. For instance, a copper ore containing 1.72% cop per, largely as chalcolcitev and 4.3% iron, largely as pyrite, was subjected to ?otation with-the 45 following reagents, with the recoveries indicated. of the mercaptans, that is, the sulphides and di sulphides, are substantially as good collectors for the sulphide ores as the mercaptans themselves. On the other hand, unlike mercaptans they do not react with dissolved base metal salts so that they can be used with circuits containing various amounts of these salts without loss. In the case of certain ores the use of sulphides and di-sulphides makes possible a considerable saving 60 " Lb. per Iron re- Copper Reabent ton covery recovery Percent Percent 50 0.05 72 Amy] xanthatm. ................. _- 0. 05 91 92 Amy] mercaptan .................. _ . Ethyl xanthate _______________ __>.-.- 0. 05 74 93 81 In all of the above quoted tests a frother was. in the alkaline reagents which otherwise are re ' used in conjunction with the various collectors, quired to eliminate the soluble salts before using the amount of frother being the same in each mercaptans or other ?otation reagents, such as case. the xanthates. ' , I have also found that the mercaptans are par 55 2 2,125,337 . ticularly well suited to collect oxidized copper The following table illustrates a ?otation op eration conducted upon the copper-bearing sul minerals such as malachite, azurite, cuprite and melaconite. Thus an 80% recovery of malachite from a 10:40 mixture ofmalachite and calcite required 1.3 lbs. per ton isoamyl mercaptan or phide mineral, chalcocite. ‘ Reagents ‘1.9 lbs. per ton n-butyl mercaptan, Whereas 2.0 lbs. per ton isoamyl xanthate and 4.1 lbs. per ton n-butyl xanthate were required to give the same recovery. Similar results were obtained with 10 azurite. 0.05 amyl merca Recovery percent an _______________________ __'_ _________ _. 100 0.05 amyl mercaptan+0. 5#/'1‘ hydrated CuSO4 0.05 amyl sulphi . 27 _______________________ __'__ _ 0.05 arnyl sulph1de+0.25#/T hydrated CuSOi A particularly good ?otation of oxidized cop per minerals by mercaptans is of interest in the ?otation of sulphide ores since the. greater por (01.05 amyl s [J 100 _ de ______________________ __ __ _ 100 .05 amyl disulphide+0.25#/T hydrated OuSOl ________ _. tion of the copper loss in such minerals ‘is due Similarly with a' copper ore in which'the cop 15 to the presence of the values in oxidized form. per existed as chalcopyrite and chalcocite, to gether with some copper in solution, the follow ing results were obtained. A sulphide copper ore carrying chalcopyrite as the principal copper mineral, assaying 1.95% 10 99 15 copper, of which 0.17% was oxidized copper, gave a tailing of 0.26% copper when ?oated with 0.10 lb. per ton sodium ethyl xanthate. The Amount of Recovery Reagent reagent percent 20 copper content of the tailing was reduced to 0.12% when isoamyl mercaptan was substituted pound for pound for xanthate. Benzyl mercaptan; _______________________ _. Benzyl mercaptan _______ _ . ' The following data illustrates the advantage +Lime _ _ _ . _ _ _ _ _ _ _ _ _ _ _ _ _ , _ _ _ _ _ _ _ . __ Benzyl disulphide _________________________ _ _ 0. 10 40 0. l0 ________ _ _ 4. 0 84 0. 10 87 25 secured from the use of higher mercaptans, 25 showing the amount of reagent in pounds per - I have furtherdiscovered that mercaptans or thiophenols are much more e?icient as ?otation reagents for sulphide zinc-bearing ores than ton required to ?oat 80% of the ore indicated. . 30 Reagent Ethyl mercaptan .................. _. 35 10:40 mixture 1215333380 n-Propyl mercaptan... _______ _ . n-Butyl mercaptan____ ____ . plus 600 mesh calcite malachite and calcite . Isoamyl mercaptan ________________ _ _ xanthates. of minus 100 mesh chal_ 0. 14 ______________ __ 0. 06 2. 8 0. 035 1. 9 0. 02 1. 3 _ In the above experiments the mercaptans or thioalcohols were added to the ?otation cell as 40 alcoholic solutions. Obviously the reagent may be added to the ball mill prior to ?otation or to the ?otation cell ‘or to some conditioning or that the copper activated sphalerite is particu larly amenable to ?otation by reagents which are well suited to the ?otation of cupriferous ores. Among these reagents are the organic hy 40 drosulphides and their oxidation products as above set forth. emulsifying tank between the grinding and ?ota- . tion stages. Reagent additions may be made in 45 the solid or liquid form or' in solutions in some inert solvent such as methyl alcohol, an amine, a phenolic compound or one of the usual ?ota tion oils, such as pine oils. The greater solu bility of mercaptans as compared with .thio 50 phenols is of distinct advantage in this particular. The use of the higher hydrosulphides is ad vantageous as compared with the use of the lower hydrosulphides in that the. former are con siderably less volatile than the latter and this, 55 together with the fact that smaller amounts of the higher hydrosulphides are required, minimizes the danger of the reagent occurring in the air . It has been known for some time that the 30 use of soluble copper salts makes zinc sulphides more amenable to ?otation reagents. I have found that the bene?cial effects of copper salts in the ?otation of zinc sulphide is due to the formation of a thin coating of copper sulphide 35 upon the surface of the mineral and furthermore I have found that the use of mercaptans or _ thiophenols in ?oating copperractivated sphal erite makes possible the ?oatability thereof over a 45 substantially-extending alkaline range, which is not secured by the use of xanthates . Thus, with a certain amount of xanthate‘, material depres sion results at pH 12, whereas such an e?ect doesrnot manifest itself when using the same 50 amount of- the corresponding mercaptan until about pH 13. This discovery is 'of practical value in the treating of iron-bearing zinc ores or pyritic copper ores. It is illustrated in the following table: 55 Recoveries. to a dangerous concentration. Reagents Further, I have discovered that the oxidation 60 products ofv organic hydrosulphides, especially sulphides and disulphides, are substantially as good collectors for sulphide minerals as are the 65 Zn 0 .10 K. ethyl xanthate _______ __ 2 . CaO __________________ _>..._ by organic'sulphides and disulphides. 0. 0. salts. Flotation of sulphide ores containing solu ble salts is therefore prohibited if organic hydro 70 sulphides are used as reagents unless the pulp is ?rst freed of the soluble salts by the addition of a precipitation agent or other metal ion abstract ing agent.- The use of sulphides ‘or disulphides of the above type obviatesthe necessity and cost of adding such a precipitation agent. Fe 0 .75#/T CuSO4, :- 11,0 ______________ __. .... __ hydrosulphides themselves. Copper-bearing sul phide minerals in particular are readily ?oated Unlike organic hydrosulphides, organic sul phides do not react with dissolved base-metal percent 65 2 0 .m/r amyl 011804, mercaptan 5 mo ____________ 0 .08 4.0 0:10 70 ' A great many organic compounds of the gen eral-formula RSH are known and probably, many ' others exist which have not been speci?cally identi?ed. I have found that ethyl, propyl, butyl, amylphexyl and heptyl mercaptans as well as 75 3 2,125,387 their oxidation products, are particularly e?lcient for the purpose ‘set forth. Broadly speaking, the reactions of these various compounds are similar of an alkyl mercaptan higher in the series than ethyl mercaptan. , ‘ 3. A method of recovering oxidized copper ore values from the gangues in crude copper ore, and hence they are to be construedlin this appli cation as being typical and I do not wish to be I which consists in subjecting the crude ore' to a froth ?otation operation in the presence of amyl limited speci?cally to any of the particular re agents named, but the claims appended hereto should be construed broadly. What I claim is: 1. A method of recovering values from oxidized 10 ores which consists in subjecting the same to a ?otation operation in the presence of an alkyl mercaptan higher in the series than ethyl mer captan. 15 2. A method of recovering values from oxidized copper and zinc ores‘ which consists in subjecting the same to a-?otation operation in the presence mercaptan. 4. A method of recovering values from ores containing both sul?des and oxidized products of the same metal which comprises subjecting 10 the same to a ?otation operation in the presence of an alkyl mercaptan higher in the series than ethyl inercaptan. 5. A method according to claim 4 in which the ore contains copper sulfide and oxidized copper 15 compounds. _ ANTOINE M. GAUDIN.