US2289996A - Process of separating chalcopyrite ores - Google Patents

Description

Patented July. 14, 1942 2,289,996, rnoonss or sl'll'AgfilsNG CHALCOPYRITE Anderson W. Ralston and Ervin W. Segebrecht,

A, Chicago, Ill., asslgnors to Armour and Company, Chicago, Ill., a corporation of Illinois No Drawing.

Application November 13, 1939,

Serial No. 304,267

3 Claims.

This invention relates to the recovery of copper pyrites from orescontaining the same, and it comprises processes wherein such ores are subjected to froth flotation in the presence of primary aliphatic amines having from twelve to eighteen carbon atoms and water-soluble salts thereof.

Chalcopyrite ores contain copper as a double sulflde of copper and, iron. In addition to the valuable .copper and iron constituents much silica in the form of quartz is found in the ore. At the present time these chalcopyrite ores, and by that we mean any ore containing double sulfide of copper and iron, are subjected to froth flotation for the separation of the copper con stituents. Many diiferent flotation agents have been proposed for effecting this separation. Many of them, however, are quite. expensive, relatively large amounts of costly complex organic compounds being required. What is deisired in the art is a flotation agent which can be used under all conditions of acidity or alkalinity'in the. aqueous slurry of ore pulp, which will not be expensive on a cost-per-tcn basis, and which is readily available. We have now discovered that primary aliphatic amines having from twelve to eighteen carbon atoms, as well as amine salts thereof, are highly effective agents for performing this separation. We have discovered that only very small quantities of these agents are required in contrast to much larger amounts of other flotation agents hitherto proposed. Moreover; we have discovered that both the amines as such and their corresponding water-soluble salts are effective. The importance of this is that the flotation can be performed successfully regardless of the acidityor alkalinity of the ore pulp. Consequently, we need not so control the pH value of the pulp that is on the alkaline side or the acid side, as

conditions might dictate.

Although the amine salts hate been suggested as flotation agents for the separation of phos-' phate ores andother non-sulfide ores, we are not aware that these agents have been hitherto proposed for the separation of the speciflc ore of which the presentfinvention is concerned. In

amines, as well as their salts are highly effective. on the other hand, the primary amines alone are very much better agents for the froth flotation separation of phosphate ores, When phosphate ores are floated with amines the silica appears in the concentrate and the phosphate values in the tailings. When chalcopyrite is subjected to flotation it is the chalcopyrite which appears in the concentrate and the silica in the tailings. 'Thus each and every ore behavesdifferently when subjected to froth flotation in the presence of a primary aliphatic amine or its corresponding water-soluble salt, and no pre-' dictions can be made with respect to the behavior of one ore from the behavior of another.

We emphasize this point so that it may be understood that insofar as the amines and their salts are used as flotation agents, whether they are commercially suitable with respect to cost, and what constituent in the orefloats, can only be determined by'experiment and cannot be predicted in advance.

In the present invention we have discovered that both the primary amines and the corresponding water-soluble salts are effective, and each causes commercially practical amounts of the copper iron sulfide to be concentrated in the concentrate.

our copending application filed of even date herewith, we describe the use of primary aliphatic amine salts. as flotation agents for the separation of copper sulfide from ores containing' the same. But, as pointed out in-that application, the amine 'salts are very much more effective than the corresponding amines. In the presentapplication we have discoveredthat the 55 usually the hydrochloride or the acetate.

All those primary aliphatic amines, and water- 'soluble salts thereof, which have twelve or more containing twelve or more carbon atoms. ,Such

nitriles can be readily prepared by reacting mixtures of fatty acids with ammonia, and the mixtures of fatty acids can inturn be obtained from any of the common fats by saponiflcation and recovery ofthe fatty acids from the correspondingsoaps. a

For purposes of illustration we shall describe our invention with particular reference to the use of dodecylamine and dodecylamine acetate.

This amine is readily obtained from the corresponding fatty acid.

The ore used had the following analysis: SiOz 48.11%, copper 12.01%, iron 17.51%. The ore was ground and admixed with water in the.

into a flotation cell flllea with water and t e suspension adjusted to a pH of 8.1 by the addition of sodium hydroxide, Docecylamine, in the amount equivalent to 0.05 pound per ton of ore was then added and the mixture subjected to froth flotation. The ore used amounted .to 494.65 parts by weight. After flotation a concentrate amounting to 252.26 parts by weight was obtained. This concentrate analyzed'as follows: SiOz 7.30%, Cu 24.50% and Fe 31.00%.

The tailings amounted to 252.39 parts by weight and analyzed as follows: SiOz 87.30%, Cu 2.33% and Fe 4.56%.

From this data it is apparent that 98.57% of the silica appeared in the tailings and 7.44% in the concentrate, 90.7% of thecopper appeared in the concentrate and 9.03% in the tailings and 86.72% of the iron appearedv in the concentrate with 13.28% in the tailings. This gives a copper recovery of 90.97%, an iron recovery of 86.72%

i and a selectivity co-efiicient of 28.3.

Of special interest is the very small amount of primary amine used. We know of no separation hitherto practised on chalcopyrite which uses so little flotation agent.

We' shall now give an example using dodecylamine acetate as a flotation agent. In this case the chalcopyrite ore analyzed 49.61% of .silica as S102, 15.21% of copper and 17.15% of water-soluble salts thereof.

On this basis all of the silica appeared in the tailings and none in the concentrate, 97.42% of the copper appeared in the concentrate and 2.58% in the tailings, and 95.91% of the iron appeared in the concentrate and 4.09% in the tailings. This gives a copper recovery of 97.42% and an iron recovery of 95.91%. The selectivity index is, therefore, infinity since no silica appears in the concentrate.

From the foregoing results, which can be duplicated when other primaryamines and water-soluble salts having six or more carbon atoms are used, it is apparent that these flotation agents are highly effective when only small amounts thereof are used. Although more of the agent can be added to the slurry of ore such is wasteful.

We have not described the flotation step in detail since that is well known to those skilled: in the art. Our invention is primarily concerned with the use of the aforesaid flotation agents for the separation'of chalcopyrite from ores containing the same.

Having thus described our invention, what we claims is:

1. In the froth flotation of copper iron sulfide from ores containing the same the step which comprises subjecting the ore to froth flotation in the presence of a flotation reagent consisting of at least one primary amine compound chosen from the group consisting of primary aliphatic amines having at least twelve carbon atoms and 2. The process as in claim 1 wherein the flotation agent comprises dodecylamine.

3. The process as in claim 1 wherein the flotation agent comprises dodecylamine acetate.

ANDERSON w. RALSTONs ERVIN w. SEGEBRECHT