US1554216A - Froth-flotation concentration of ores - Google Patents

Description

Patented Sept. 22, 1925.

UNITED STATES- PATENT OFFICE.

CORNELIUS H. KELLER, OF SAN FRANCISCO, CALIFORNIA, ASSIGNOR TO MINERALS SEPARATION NORTH AMERICAN CORI'OBATION, OF NEW YORK, N. Y., A COB- IORATION O'I MARYLAND.

FROTH-FLOTATION CONCENTRATION OF ORES.

No Drawing.

To all (whom it may concern:

Be it known that I, CORNELIUS H. KELLER, a citizen of the United States, and a resident of San Francisco, county of San Fran-' cisco, State of California, have invented certain new and useful Improvements in Froth-Flotation Concentration of Ores, of.

which the following is a specification.

This invention relates to the froth-flotation concentration of ores, and isherein described as applied to the concentration of certain ores with mineral-frothing agents in the presence of'certain organic compounds containing sulphur.

It has been found that certain sulphur derivatives of carbonic acid greatly increase the efliciency of the froth-flotation process when used in connection with mineralfrothing agents. The increased efliciency shows itself sometimes in markedly better recoveries, sometimes in effecting-the usual recoveries with greatly reduced quantities of the usual mineral-f'rothing agents, and

sometimes in greatly reducing the time needed for agitation to produce the desired recoveries.

The invention is herein disclosed in some detail as carried out with salts of the sul- .phur derivatives of'carbonic acid containing an organic radical, such as an alkyl radical, and known as xanthates, as the new substance. These form anions and cations in solution. Excellent results were also obtained by agitating ore pulps with the complex mixture produced when 33%% of pine oil was incorporated with an alcoholic solution of potassium hydrate, and xanthates or analogous substances were produced by 40 adding carbon disulphide to this mixture.

The galena-bearing froth obtained with xanthates or analogous substances used at the rate of 0.2 pounds per ton of ore had a characteristic bright sheen, like a plumbagohearing froth, and seemed to make a more coherent froth than when other materials were used on the same ore.

In general the substances referred to are not mineral-frothing agents,producing only a sli ht scum, and some evanescent frothy bublrles, when subjected to agitation which would produce mineral-bearing froth on an ore pulp in the presence of a mineralfrothing agent. The substances are efiecin concentrating Application filed October 2a, 1923. 'Serial 110. 610,242.

tive in enabling a selective flotation of lead and zinc, and cause uncombined silver, if present, to tend to go into the lead concentrate rather than with the zinc, where these are separated in separate concentrates. Usually pre-agitation is unnecessary, thebrightening and other effects seeming to be practically instantaneous. The pulps may be either acid, alkaline or neutral according to circumstances. Two sticks of caustic potash weighing perhaps 15 grams were partly immersed in about 80 cc. of commercial carbon disulphide and kept for about ten days in a closed bottle containing some air in the warm region of the laboratory where were the hot plates used for drying. These eventually yielded a yellow or orange salt which was used with pine oil at the rate of approximately half a pound to a ton of ore Hibernia ore from Timber The test was with Butte Mining (Jompany.

a neutral pulp, and the concentrates were seen to be clean with brightened lead sulphide particles.

For laboratory purposes potassium xan thate was prepared as follows:

198.4 grams of 88.5% caustic potash was dissolved in 524 grams ethyl alcohol (denatured #5 formula) at a temperature of 124 F., in a reflux condenser. The solution was cooled to 58 F. It contained a large excess of alcohol over the theoretical amount needed for the subsequent reactions. To this was added, while stirring, and in a cooling bath, the theoretical amount of carbon disulphide. The reaction was substantially instantaneous, producing a thick pulp of potassium xanthate. The pulp was cooled and centrifuged in a laboratory machine, yielding crystals containing about 20% moisture. The yield thus obtained was 74.7%. Another 17.5% was obtained 'by evaporation of the mother liquor. Both the centrifuged crystals and the residue from the mother liquor gave excellent results in flotation. It was found in cases where sulphuric acid was used that the centrifuged material yielded better results than the uncentrifuged.

A pulp of Anaconda slimes which had been stored for several da s assaying 2.95% cop r (a part being oxi ed copper mineral was treated with cresylic acid as frothing agent and potassium xanthate, the latter used at the rate of half a pound to a ton of the slimes. With no pre-agitation, and fifteen minutes agitation in a laboratory subaeration machine these slimes yielded a concentrate containing 15.6% copper, a middling containing 0.48% copper and a tailing containing 0.082% copper. The small proportion of silver present was recovered in about the same proportions. Similar results were obtained with the use of sodium xanthate and General Naval Stores No. 5 flotation oil, a steam distilled pine oil.

A. pulp of Cash Mine ore subjected first to agitation for ten minutes with a mixture of 0.3 pounds per ton of potassium xanthate with a small proportion of a 10% or a saturated solution of naphthalene in xylene, to yield a lead concentrate, and then subjected to agitation for ten minutes with copper sulphate 0.2 pounds per ton, Barrett 1 flotation oil 1.0 pound per ton, and General Naval Stores #5 flotation oil 0.1 pounds per ton, yielded the results shown in the following table. Attention is called to the recovery of 95% of the lead in a concentrate containing 87% of the silver but containing only 5% of zinc, while 70% of the zinc was recovered in the zinc concentrate.

ico ore was agitated for ten minutes with potassium xanthate 0.15 pounds per ton and the same amount of coal tar creosote to yield a lead concentrate. The remaining 0 pulp was agitated for fifteen minutes with 0.2 pounds per ton of copper sulphate, 1.2 pounds per ton of water-gas tar, and 0.05 pounds per ton of steam distilled pine oil. The results are shown in the following San Francisco Mines of Mexico. I

% Assays. Recoveries.

7 Ag. i (UL) Pb. Zn Ag Pb. Zn.

Heads 100. 0 l6. 5 9. 4 16. 1 12.2 67.0 64.0 12.0 49.4 83.2 9.1 28. 9 23. 6 3. 6 43. 4 41. 2 l1. 1 78. 0 Tails 58.9 4.5 1.5 6.0 9.4 5.7 12.9

Similar results were obtained with thisphate, 1.3 pounds Barrett No. 4: flotation oil,

and General Naval Stores No. 5 flotation oil 0.1 pounds, all per ton of ore, to yield a zinc concentrate.

During a seven and one-half hours run on current Anaconda slimes at the rate of one hundred and eleven tons per twentyfour hours in a mineral separation standard machine from a feed containing 3.28% copper, 0.26% being acid soluble copper, there was recovered a concentrate containing 11.43% Cu. and 30.9% insoluble,-the latter being a proportion desirable for smelting. The tailings contained 0.29%" copper of which 0.20% was acid soluble copper. This test was run at a temperature of 82 F. using for reagents, 7.89 pounds of kerosene acid sludge, 21.6 pounds of chamber sulphuric acid, 2.36 pounds of hard wood creosote, and 2.92 pounds of a twenty per cent solution of potassium xanthate in water all quantities being in pounds per short ton or ore.

Anaconda old gravity. concentration tailings reground for flotation were treated at the rate of four hundred and eleven tons per twenty-four hours in a mineral separation standard machine provided with a porous bottom in the spitzkasten through which air was admitted. From a feed containing 0.52% copper, of which 0.12% was 0 acid soluble copper there was recovered a concentrate containing 5.72% copper and 48% insolubles. The tailings from this contained 0.13% copper of which 0.08% was acid soluble. This test was run at a temperature of 50 F. using for reagents per ton of solids, 0.67 pounds of a 30% solution of potassium xanthate in water, 3.96 pounds of kerosene acid sludge, and 11.45 pounds of chamber sulphuric acid.

Anaconda ore slimes containing 3.28" copper, of which 0.45% was acid soluble, were subjected to froth-flotation concentration at 70 F. with 7.8 pounds per ton of dry hydrated lime, 0.132 pounds per ton of steam distilled pine oil, 0.38 pounds per ton of destructively distilled pine oil (G. N. S. #11 flotation), and 0.69 pounds per ton of potassium xanthate in solution, yielding concentrates containing 13.76% copper and 34.7% insolubles, with a tailing of 0.317% copper of which 0.173% was acid soluble. This represented a recovery of 92.2%.

The lime was mixed with water and fed as a watery paste with the slimes to the first agitator of a series of nine standard minerals separation agitators or mixing compartments through which the pulp passed in series at the rate of 97 tons in 2 1 hours. The #11 pine oil was added at the seventh agitator, and 0.6 pounds per ton of the xanthate at the ninth. The pulp returned through fourteen spitzkastens, each equipped with a Brown aerator and circulating deyice. At the sixth spitzkasten the balance of the xanthate was added. At the tenth spitzkasten the steam distilled pine oil was added. The froth from the first nine spitzkastens was collected as a finished concentrate, that from the remaining five was returned to'the first as a middling.

It has also been found thatfor the frothflotation concentrationof certain ores, such as Calumet & Hecla, Britannia, Cananea and Moctezuma,. mother liquor obtained from centrifuging the above described xanthates in the process of manufacture of said xanthates may be used with about the same proportions of mother liquor as of the xanthate crystals specified with results as good or better than those abovegiven.

A pulp of 80 mesh Calumet and Hecla slimes containing 0.45% copper, mostly native, with considerable mineral occluded in the coarser particles of gangue, was agitated five minutes 'with 0.3 pounds potassium xanthate, thenwas agitated for twenty min-- utes with 0.4 pounds steam distilled pine 011, all per ton of ore. The concentrate thus obtained was agitated for fiveminutes and 'the froth separated to form a finished concentrate, the remainder forming a middling. The results are shown in the following table:

Re Wt. Assays coveries Cu. Cu.

A' Chinese graphite ore containing 49% carbon as graphite, chiefly in amorphous state, ground to mesh, was agitated ten minutes with 0.2 pounds potassium Xanthate and 0.15 pounds pine oil, both per ton of ore, yielding a froth concentrate and a tailing. The concentrate was reagitated for five minutes to yield a finished concentrate anda middling' The finished concentrate contained 72.8% carbon as graphite, the middling 36.8%, and the tailing 15.2%. These represented respectively 79.2%, 10.2% and 10.6% of the original graphite content of the ore.

In the absence, of xanthate the same ore required a larger amount of mineral-frothing agent and longer agitation to produce the same results.

Having thus described certain embodiments of the invention, what is claimed is:

1. The process of concentrating ores which ore with a mineral-frothing agent and a sulphur derivative of carbonic acid adapted to form in solution anions and cations and adapted to co-operate with the mineralfrothing agent to produce by the action of both a mineral-bearing froth containing a large proportion of a mineral of the ore, said agitationbeing so conducted as to form such a froth, and separating the froth.

2. The process of concentrating ores which consists in agitating a suitable pulp of an ore with a inineral-frothing agent and a salt of a sulphur derivative of carbonic acid adapted to form in solution anions and cations and adapted to 'co-operate with the mineral-frothing agent to produce by the action of both a mineral-bearing froth containing a large proportion of a mineral of the ore, said agitation being so conducted as to form such a froth, and separating the froth.

3. The process of concentrating ores which consists in agitating a suitable pulp of an ore with a mineral-frothing agent and a salt of an .alkyl sulphur derivative of carbonic acid adapted to co-operate with the mineralfrothing agent to produce by the action of both a mineral-bearing froth containing a large proportion of a mineral of the ore, said agitation being so conducted as to form such a froth, and separating the froth.

4. The process of concentrating ores which consists in agitating a suitable pulp of an ore with a mineral-frothing agent and a salt of an ethyl-sulphur derivative of carbonic acid adapted to co-operate with the mineralfrothing agent to produce by the action of both a mineral-bearing froth containing a large proportion of a mineral of the ore, said a tation being so conducted as to form such a froth, and separating the froth.

5. The process of concentrating ores which consists in agitating a suitable pulp of an ore with a mineral-frothing agent and an alkali-metal salt of an ethyl-sulphur derivative of carbonic acid adapted to co-operate with the mineral-frothing agent to produce by the actions of both a mineral-bearing froth containing a large proportion of a mineral of the ore, said agitation bemg so conducted as to form such a froth, and sepa- I rating the froth.

6. The process of concentrating ores which consists in agitating a suitable pulp of an ore with a mineral-frothing agent and an alkaline xanthat-e adapted to co-operate with the mineral-frothing agent to produce by the action of both a mineral-bearing froth containing a large proportion of a mineral of the ore, said agitation being so conducted as to form such a froth, and separating the froth.

'Z. 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 a Xanthate.

8. 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 potassium xanthate.

9. 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 a xanthate and a frothing agent.

10. The process of concentrating ores which consists in agitating a suitable pulp of an ore with a mineral-frothing agent and a sulphur derivative of carbonic acid containing an organic radical and adapted to co operate with the mineral-frothing agent to managers produce bearin froth containing a large proportion of a mineral of the ore, said agitation being so conducted as to form such a froth, and separating the froth.

11. The process of concentrating ores which consists in agitating a suitable pulp of an ore with a mineral-frothing agent and a salt of a sulphur derivative of carbonic acid containing an organic radical and adapted to co-operate with the mineralfrothing agent to produce by the action of both a mineral-bearing froth, said agitation being so conducted as to form such a froth,

and separating the froth.

In testimony whereof, I have aflixed my 3 signature to this specification.

CORNELIUS H. KELLER.

by the action of both a mineral- 2