US1763851A - Concentration of ores - Google Patents

Description

Patented June 17, 1930 PATENT OFFICE BENJAMIN I. JOHNSON, F GARFIELD, UTAH CONCENTRATION 013 031518 No Drawing.

This invention relates to the concentration of ores, minerals and the like by flotation, and has for its object the provision of certain improvements in flotation processes, and more particularly the froth flotation process.

The present invention is based upon the discovery that tetrathio diphospho organic compounds are effective flotation agents. I have found that these compounds, in which two 0 molecules of an organic phosphorus and sulphur containing compound are made to combine into a single molecule, with two phoshorus atoms bonded through two intervenmg and linked sulphur atoms, have a marked selective action on the sulphide minerals as distinguished from gangue minerals; and when used in a flotation process, float the sulplhide minerals readily with an-attendant hig recovery of the metal values.

I have also found that smaller amounts of these tetrathio diphospho organic compounds are needed to produce equivalent or better results in the flotation operation than other organic flotation agents heretofore generally used.

My investigations indicate that certain of the tetrathio diphospho organic compounds have insfiflicient frothing power to constitute a complete agent in froth-flotation, so that an appropriate frothing agent, such as pine oil, cresylic acid or the like, may be employed in conjunction therewith, in carrying out such froth-flotation operation.

The flotation agent which is typical of these tetrathio diphospho organic compounds may be conveniently made by addmg diethyl dithio phosphoric acid, or its metallic salt, during continuous stirring, to strong sulphuric acid, which must be cooled as soon as the reaction commences, to prevent decomposition. The reaction, which continues for upwards of twenty minutes, accompanied by evolution of sulphur dioxide, may be represented as follows:

2 c o rssn B so omlmmss-ssmomom so, 211.0

The principal product of this reaction is a crystalline solid, of mild odor, which melts at 7 2-7 3 0., without decomposition or change in properties.

Application filed October 31, i928. Serial No. mazes.

I propose to call this product tetraethyl tetrathio diphosphate, although other names may be equally appropriate. The following 1s a comparison of determined and theoretical constants of this product:

Determined Theoretinal Percent sulphur. 35. 4 Per cent phosphorus 16. 6 Molecular weight 369. 85

R 0 I Rao i s R10 i mo expresses what I believe to be the constitution so of the class of com ounds which I intend to claim for use in otation. In the general formula, R R R and B, may represent any alkyl or aryl radicals or substituted derivatives thereof. The radicals maybe all alike, as in the tetraethyl compound described in detail above; or some, or all, may be different. Methyl, propyl, phenyl and "cresyl radicals may be mentioned, for example, as among those which can be represented by the s mbols R R R, and R above. While'I believe that the above formula correctly represents the reaction product of an alkyl or aryl dithio phosphoric acid or its metal ic salt with an oxidizing a cut, it is understood that where I have used t is formula in the claims such reactionproduct is indicated thereby.

Generally, these tetrathio diphospho organic compounds may be prepared throu h the reaction of any of the organic di=th1o 1.00

phosphoric acids, or their metallic salts, with any suit-able reagent that will effect the oxidation described. I may use any suitable oxidizing agent, such as sulphuric acid, the halogens, hypohaloids, chromic acid, dichromates or permanganates. Typical results obtained by adding these reagents to a mineral ore pulp and subjecting the resulting mixture to flotation are tabulated as follows:

Utah Copper Company mill heading ground to a fine pulp and modified with burned lime and sodium cyanide was subjected to flotation in a J anney Laboratory machine. Gresylic acid was used at the rate of .3 ounds per ton of ore and tetraethyl tetrathio diphosphate used at the rate of .05 lbs. in Test 1 and at the rate of .025 lbs. in Test 2.

Heading Concentrate per cent Fe Rougher per cent Cu Rougher per cent Tailing per cent Fe Test Per cent Per cent Cu Fe I have found that these tetrathio diphospho organic compounds are effective flotation agents when mixed with a pulp so modified as to show either acid, alkaline or neutral reaction, and the resulting mixtures subjected to flotation operations.

I claim:

1. The improvement in the concentration of ore by froth flotation which comprises subjecting the ore in the form of a pulp to a froth flotation operation in the resence of the reaction product of diethyl 'thio phosphoric acid with strong sulphuric acid.

2. The improvement in the concentration of ore by froth flotation which comprises subjecting the ore in the form of a pulp to a froth flotation operation in the presence of the reaction product of a metallic salt of diethyl dithio phosphoric acid with strong sulphuric acid.

3. The improvement in the concentration of ore by froth flotation which comprises subjecting the ore in the form of a pulp to a froth flotation operation in the presence of tetraethyl tetrathio diphosphate.

4. The improvement in the concentration of ore by froth flotation which comprises subjecting the ore in the form of a pulp to a froth flotation operation in the presence of a compound represented by the formula B40 in which R R R, and R stand for any alkyl or aryl organic radicals or substituted derivatives thereof.