US1497699A - Concentration of ores - Google Patents

Description

Patented dune l 7, 1 924.:

T-En M" n. sarnn, ornnw Rooi'afELLn, new Yam, assienoa'ro'mnrnns' nncovnnr COMPANY, OF YORK, N. Y., A. CORPORATION 015 IMAIIIN'E.v

concnn'rnarron or case.

No Drawin g.

To all whom it may concern/.5

. Be it known that l, RALPH E. SAYRE, a citizen of the United States, residing at New Rochelle, in the county of Westchester, 5 State of New York, have invented certain new and usefullmprovements inthe Concentration of Ures; and I do hereby declare the followingto be a full, clear, and exact description of the invention, suchas will n enable others skilled in the art to which it appertains to-Inake and use the same.

This invention relates to the concentra-. tion of ore minerals, and the like, by flotation, and 11 2s for its object the provision of 15 certain improvements in flotation processes, and :"IDOI'B particularly the froth flotation processes.

- The present invention is based upon the discovery that the salts of substituted 2o dithiocarbamic acids are effective flotation reagents, particularly in non-acid or alkaline pulps. l have found that the salts-of substituted dithiocarbamic "acids have a marked selective action on sulfide minerals, as distinguished from gangue minerals, and when used as flotation agents in the customary flotation processes cause the sulfide mineral to'float'readily withan attendant high recovery of the metal "values. My investigations indicate that the salts of substituted dithioc'arbamic acids are substantially lacking in .frothing power, so that an appropriate frothing agent, such as pine-- oil, terpineol, or the like, should be' employed in conjunction therewith in carrying K out the flotation operation.-

The salts of substituted 'dithiocarbamic. acids (dithiocarbamates) may be' prepared in accordance with well-known methods. In

40 general, the most convenient procedure for preparingsuch saltsconsists in adding an alkali dissolved in alcohol to a mixture of carbodbisulfide and an amine. The aryl' dithiocarbamates (for example, potassium phenyldithioarbamate, C H NHS K) may be prepared in this manner employing an arylamine. "In; preparing the alkyl dithiobarbamates for example diethylammonium .dieth ldit hiocarbamate tc no ncsmu (0 an alkylamine may be dissolved in benzene and treated with carbon bisulfide.

In order to obtain the reaction product.

' in solid form, it is usually desirable to treat thereaction mixture with ether or with some other solvent in which the dithiocarbasubstituted dithiocarbamic acids are in e 'carbamates (such as the alkali and alkylties the aryl dithiocarbalnates are even more have ound that the readily soluble dithio- Application filed November as, 1923; serial-no. eraser),

mate is but slightly soluble. It is not necessary for the purposes of the-present invention to isolate thedithiocarbamate from the reaction mixture. Thus, in the practice of the present invention, the dithiocarbarnates may be used as crude reaction 'prdducts without being isolated from the reaction mixture.

-.-The alkali and alkylammonium salts pit eral readily soluble in water and alco ol. The heavy metalsalts (such as the lead, zinc, iron etc. salts) may be obtained as precipitates bytre'ating the dissolved dithioammonium dithiocarbamates) with a dissolved salt of the heavy metal. Thus, for example, lead-phenyl dithiocarbamate is pro duced by mixing solutions of lead acetate and potassium-phenyl dithiocarbamate. lln general, the heavy metal dithiocarbamates are only sparingly soluble even in hot water.

I; have found that while the alkyl dithiocarbamates possess marked flotation propereffective 'fiotatiop agents, and for this reason I prefer, in carrying out the present .invention, to use the aryl compounds.

In racticing the present invention, ll

carbamates give the best results when .introduced into {the flotation circuit immediately before the flotation operation. The Same procedure may be employed when. using the less-soluble dithiocarbamates, such as theheavy metal dithiocarbamates, the salts being dissolved in-hot water before bein introduced- .into the flotation circuit. W en using the heavy metal dithiocarbamates I prefer, however,to add the sparingly' soluble.dithiocarbamates to the ore pulp prior to the final grinding operation.

The quantity of the dithiocarbalnate fo be f employed in practicing the present invention 1 depends tosome extent upon the particular {00 salt being used and the particular ore being treated. In general, I have found that onefifth ,of-a pound, and less, per ton of dry ore givessatisfactory results. v

I prefer to employ the dithiocarbamates' 05 as flotation agents in a neutral (that is nonacid) 'or' alkaline pulp. Any alkali, such as caustic-soda, soda ash, orlinie, may be added to the ore pulp in order to make the pulp neutral 'or alkaline. 'Lime, on the whole,

is the most suitable a'nd'available alkali for this purpose. The alkali should'be'added to the-ore ulp before the final grinding.

' The thioca'rbamates' are of some value I as flotation. agents in acid typical flotation results obtained in the practice' ofthe present invention. In all of the floats reported in this table, 500 grams of a partiallcyoground copper sulfide ore (of the Utah pper Company). assaying 1.34%

' copper were ground for twenty minutes-in a pebble mill with 250 c. c. of water and an amount of lime equivalent tofour pounds per'ton of dry ore. The flotation operation wascarriedout in a laboratory size Callow rougher cell, after diluting-the ground ore pulp to'about 2.5 liters. The lead, iron and zinc dithiocarbamates were added to the ore pulp at the start'of the grinding operation, while the potassium dithiocarbamates were added after the grinding operation and im mediately preceding the flotation operation. In each case] a drop of'the terpineol was added to the ore pulp immediately preceding flotation.

Amount I Cone. Tunings Recov- Reagem gf ggf copper. copper. cry

Potassium pnenylditnio- Pou nd. Per cent. Per cent. Per cent. carbamate 0.2 14.5 0.28 80.8 Lead phenyldithiocarbamate U. 1 15. 5 0. 26 83. 2 Potassium o-tolyldithiocarbamate 0.1 14.1 0.32 77; 9 Iron o-tolyldithiocarbar .mate 0.1 15.6 0.30 79.1 Potassium a-uaphthyldithiocarbamate 0. 1 15. 3, 0. 29 80. 1 Zinc .anaphthyldithi .carbamatc' 0. 1 18. 4 0. 33 76. 8

It will be'understood by those skilled in j the art that the prese'nt invention is applia cable to the treatment by flotation of various kinds of mineral mixtures both natural and artificial. In the appended claims I have accordin ly employed the terms mineral' and ore 1n abroad sense 'to include'ores,

mineral'products. and all materials amenable to concentration or similar treatment'by the flotation processes.

Iclaimz I 1. The improvementin the concentration of minerals by flotation which comprises subjecting the mineral in the form of a pulp.

to a'flotation operation in the presence of a dithiocarbamate.

' 2. The improvement in the concentration of minerals by flotation which comprises subjecting the mineral in the form of a pulp to a flotation operation, in the presence of an aryl dithiocarbamate.

3. Th -improvement in the concentration of minerals by flotation whichv comprises subjecting the mineral in'the form of a nona cid pulp to a flotation operation in the presence of a dithiocarbamate.

4. The improvement in the concentration of minerals by flotation which comprises subjecting the mineral in the form of a nonacid pulp to a flotation operation in the presence of anaryl dithiocarbamate;

5. The improvement in the concentration of mineralsby flotation \vhich comprises subjecting the'mineral in the form of an alkaline pulp toa flotation operation in'the presence of a dithiocarbamate.

6. The improvement in the concentration of minerals; by flotation which comprises subjecting the mineral in the form of an alkaline pulp to a flotation operation in the presence of an aryl dithiocarbamate.

7. The improvement in the concentration of minerals by flotation which comprises subjecting the mineral in the form of a pulp made alkaline by the addition of lime to a flotation operation in the presence of an aryl dithiocarbamate.

8. The method of concentrating ores and the like which comprises subjecting the ore in the form of a suitable pulp to a flotation operation in the presence of a salt of a sub-' stituted dithiocarbamic acid.

9. The method of concentrating ores and the like which comprises subjecting theore in the form of a suitable pulpto a flotation operation in the presence of a salt of a substituted dithiocarbamic acid which salt is only sparingly soluble in water the like which consists insubjecting the ore in the form of a suitable pulp to a flotation 10. The method of concentrating ores and" I operation .in the. presenceof a heavy metal ,salt of asubstituted dithiocarbamic acid.

11; The method of concentrating ores and the like which consists inlsubjecting the ore in the form of a suitable .pulp to a flotation o oration in the presence of lead. phenyldit iocarbamate.

In'testimony whereof I aflix my si nature.

RALPH E. SA; RE;