US1839155A - Process of concentrating ores by flotation - Google Patents

Description

Patented Dec. 29, 1931 UNITED STATES PATENT oFFlCl-lg--.

HERBERT A. LUIBS, OF PENNB GROVE, NEW JERSEY,

AND ARTHUR L. rox, OF

WILMINGTON, DELAWARE, ASSIGNORS TO E. I. DU PON'I. DE NEMOURS & COMPANY, OI WILMINGTON, DELAWARE, A CORPORATION 01' DELAWARE PROCESS OI GONCENTRA'HNG OBES BY FLOTA'IION No Drawing.-

' This invention relates to improvements in the process of concentrating ores and minerals by flotation, particularly by the use of certain types of compounds which have not hitherto been employed for this purpose. It has been found that the concentration of ores by flotation can be greatly facilitated if we use in the flotation operation certain organic compounds containing the groupSH.

It has been discovered that marked flotation effects are obtained with organic complounds containing the group-SH, in which may be replaced by a metal, as the alkali metals or lead, said group being attached to a carbon of an organic radical which, if it is an aryl radical, is preferably free from amino groups ortho to the mercapto group, said carbon being in turn attached to at least one other carbon atom or to hydrogen.

All of these compounds are effective but some to a less degree than others. Many of them are extremely powerful flotation agents. The aliphatic mercaptans, for example, are

excellent flotation agents, whether they are normal or branch-chain compounds. Thev .cane and anthraquinone series are effective flotation agents, such for example as anthraquinone alpha mercaptan. Partially or completely hydrogenated cyclic compounds are also useful. As examples we may mention decahydro-naphthyl-mercaptan, tetrahydro-naphthyl merca tan. Heterocyclie compounds are also e ective, such for ex- Application filed December 13, m1. Serial No. 289,816.

ample as thiophene mercaptan, 'furyl mercaptan, pyrldyl mercaptan, thionthrene 'mercaptan, quinoline mercaptan. Such compounds also as benzyl mercaptan and furfuryl mercaptan may also be used.

In order to illustrate the effectiveness of these compounds, the following examples of processes involving their employment in representative flotation operations are submitted:

Example 1 Five hundred grams of copper ore (0.95% Cu) from the Inspiration Consolidated Copper Company were ground in a pebble mill with 450 cc. of water and 0.35 g. of hydrated lime. This pulp was transferred to a mechanically agitated flotation machine and conditioned therein for. 1 minute with pine oil and .005 g. of ethyl mercaptan. Water was then added to give a pulp of approximately solids. This dilution caused circulation of the pulp thru the spitz, and froth formation. The froth was removed for 10 minutes. A similar test was made using isoglieiilyl. mercaptan. The results are tabulated Percent Percent Percent Product a :6 ggs: Cu in Cu re- Hate tailings covered Ethyl mercaptan .025 13. 23 0.33 69.3 I20 mercaptan .050 11.55 0.36 67.2

Emample II Five hundred grams of copper ore (0.95% Cu) from the Inspiration Consolidated C0 per Company were ground in the pebble mill with 450 cc. of water and 0.35 g. of hydrated lime. This pulp was divided 'into three parts and transferred to mechanically agitated flotation machines and each part conditioned therein for one minute with pine oil and one of the aromatic mercaptans listed in the following tabulation. Water was then added to ve a pulp of approximately 20% solids. his dilution caused circulationof the froth thru the spitz, and froth formation. The froth was removed for 10 minutes. The results are indicated below:

Per cent P t Product Cu in Cu relbsJton concentamngs covered irate Blank test-pine all alone..." 0. 16 2.28 0. 90 7. 0 thiocreeol (with pine oil) 0. 014 22. oo 0. 39 59. 7 hlophenol with pine oil) 0. 01B 10. 70 0. 32 68. 0

Thio-b-naphthol (with pine oil) 0. M 9. a0 0. 45 54. 5

0.24 lb. of pine oil used, in othert'ests 0.16 lb. used.

iso-am l mercaptan.

methy -mercaptan. propyl-mercaptan. n-butyl-mercaptan. isopropyl-mercaptan. p-dichlor-phenyl-mercaptan.

v p-dichlor-phenyl-dimercaptan.

o-dichlor-phenyl-dimercaptan.. I p-methyl-iso-propyl-phenyl-mercaptan. mercapto-ortho-cresol. benzyl-mercapta-n.

Of the many compounds which fall within the scope of our invention, thiophenol may be mentioned as one of our preferred embodiments.

We have also found that remarkably strong flotation action is obtained with compounds of the general type sn in which H may be replaced by a metal, and

in which R is an organic radical, to a carbon of which is attached the group s -c sH The carrying into efiectLof the process with to several such reagents is Illustrated below.

Example III Five hundred grams of copper ore (0.95%

Cu) from the Inspiration Copper Company 5 were ground in a pebble mill with 450 cc.

water and 0.35 g. hydrated lime. The pulp was then transferred to a mechanically tated flotation machine, and conditioned or one minute with ine oil and one of the flotation a cute in icated below. Water was then ad ed to give a pulp of approximately 20% solids. This cause circulation of the pulp throu h the spitz, with froth formation. The froth was removed for 10 minutes.

The amounts of reagent used and the recovery of copper are shown below 1n connection with each specific reagent employed:

Amt. Peromt Pu'cmt P.- out Cuin Culn Ounoonct covered ton Mg salt 01 dithiobenzoic acid (with pine oil) cm 11.1 an 00.1 Crude dithioiuroic acid (with pine oll) ace 11.0 am can Zinc salt of dithioiuroic acid (with pine oil) M! 12.1 an no Sodium salt of dithiohydroxynaphthoic acid (with pine oil) 0.02 as us 514 Ne salt of dithioproplonlc acid (with pine oil) cos 14.9 as 41.0 Blank test (pine oil alone)..." an 2.: 0.00 1.0

'o.24 lb. of pine oil used W or usual am a, the use of um pine oil causing the inclusion of more gangue in the concentrate, thereby lowering the percent coppc thu'eln.

Many other compounds of the type may also be used. As examples we may mention dithiosalicyclic acid, dithiotoluic acid, p-methoxy-dithiobenzoic acid, dithiobutyric acid, dithiogluconic acid, 'dithioacetic acid, dithiovaleric acid, or their salts. Naturally compounds of this type are not all equally efiective. Among our preferred compounds of this particular grou are the magnesium and sodium salts of dithiofuroic acitci1 and the sodium salt of dithiobenzoic ac1 The new flotation agents are also, in general, adapted for use in selective flotation operations but some of them, for example, thiophenol and thiocresol, and the magnesium salt of dithiobenzoic acid, have the property, to a very remarkable degree, of selective flotation and may be employed to advantage, for example, in floating copper sulfide in preference to iron sulfide.

It is obvious fromthe foregoing illustrations that the class of com unds described constitutes unusually e ective flotation agents. These compounds are adapted for use over a wide range of conditions. Where employed for selective flotation with complex ores the ores may'of course contain more than two minerals and the process of selection carried out by merely repeating the flotation step for each ore it isdesired to recover.

The usual conditioning agents may, of course, be employed with the new flotation agents, as illustrated in the examples.

, froth flotation operation It. will be understood that the invention is not limited to thespecific classes of compounds or the specific compounds themselves mentioned above for illustrative purposes, but many other compounds not mentioned above, but which come within the scope of the following claims, may be employed. It

is to be understood that where the terms'ali-- is attached.

2. In the concentration of ores and minerals by flotation, the step which comprises subjecting the ores, in the form of a pulp, to a froth flotation operation in the presence of a compound of the type in which H'may be replaced by a metal, and R is an aromatic radical, to a carbon of which the group is attached.

3. In the concentration of ores and minerals by flotation, the ste which comprises sub ecting the ore, in the orm of a pulp, to a in the presence of a compound of the type sn', inwhich H may be replaced by a metal, and R is a radical of the group consisting of aliphatic, aromaticand heterocyclic radicals, to a carbon of which the grou is attached.

4. In the concentration of ores and minerals by froth flotation, the ste which comprises subjecting the ore, in t e form of a pulp, to a flotation o eration in the presence of a dithiofuroic aci compound.

5. In the concentration of ores and minerals by froth flotation, the step which com- 7 prises subjecting the ore, in the form of a pulp, to a flotation operation in the presence of a salt of dithiofuroic acid.

6. In the concentration of ores and minerals by froth flotation, the step which comprises subjecting the ore, in the form of a pulp, to a flotation operation in the presense of a compound of the group consisting of dithiofuroic acid and dithiobenzoic acid compounds.

7. In the process of concentrating ores and minerals, the step which comprises subjecting an ore containing copper and iron, said ore being in the form of a pulp, to a froth flotation operation in the presence of an organic compound adapted to raise copper sulfide and depress iron sulfide, said compound being of the type lit-0 in which H may be replaced by a metal, and

R is an organic radical, to a. carbon of which the group is attached.

8. In the process of concentrating ores and minerals, the step which comprises subjecting an ore, containing at least two metals, in the form of a pulp to-a froth flotation operation in the presence of a compound adapted to raise one metal and depress another, said compound being of the group. consisting of dithiofuroic acid and dithiobenzoic acid.

In testimony whereof we afiix our signatures.

HERBERT A. LUBS. ARTHUR L. i