FI76261C - FOERFARANDE FOER ANVAENDNING AV ORGANISKA DITIOSYROR VID FLOTATION AV MALM. - Google Patents

Description

76261

Method for using organic dithioic acids in ore flotation

Divided separated from application 821311

The present invention relates to the use of organic dithioic acids in ore flotation.

Organic dithioic acids are industrial products whose use has increased in recent years. They are used in particular in cosmetics, specifically as sunscreens, and in general in mixtures that can be used to protect the skin from ultraviolet rays. This use is described in FR patent 2,396,545, which discloses e.g. a method of combining unsaturated oils with diothioic acids to give compounds that protect the skin well from ultraviolet rays. On the other hand, these new ore foam collectors have been manufactured according to FR patent 2,429,617 and this appendix 7,914,692. In particular, these publications explain the use of esters, salts or acids R-S- (CH) CSSOH as collectors in the flotation of ores such as 3 n lead, chalcopyrite, zinc slurry and the like.

The invention relates to the use of some dithioic acids and their salts as collectors in ore flotation. Although it is already known to use dithiocarboxylic acids of the type RS- (CH) CSSH and their soluble salts as 2 n collectors, as described in FR Patent 7,914,692, at the top of page 2, it was not believed that acids without a thio group in the hydrocarbon chain RS- (CH) - could act as aggregators; According to the publication of FR patent 2,429,617 and its supplementary patent 7,914,692, the special properties of the collectors used in flotation were due to the presence of a thio group, regardless of the chain end of the compound used. However, according to the present invention, good 76261 2 collectors can be obtained even without a sulfur atom in the hydrocarbon chain when this ends in the group -CSSH or -CSSM, where M represents an alkali metal or ammonium. However, for a collector to be truly effective, its hydrocarbon chain must have a sufficiently high molecular weight, i.e., it is predominantly or greater; excellent results have been obtained with dithioic acids having a chain of C -C. Thus, for example, good results in foaming are obtained when the collectors are, for example, dithiouric acid, dithiomyristic acid, dithiopalmitic acid, dithio-oleic acid, etc., and their Na, K or NH salts.

4

The following non-limiting examples illustrate the preparation of aliphatic dithioic acids, as well as the use of such acids.

Example 1

A solution of 2 moles of sodium methylate in 1 liter of water. o methanol, cooled to 3 ° C and then saturated with dry hydrogen sulfide. To the solution thus obtained is added 2 moles of ethyl dithiopentanoate, o CH CH CH CH CSSC H. The solution is kept at 15 ° C for 15 h, 3 2 2 2 2 5 after which 120 ml of 10N HCl are added; sodium chloride precipitates and is removed by filtration.

The filtrate is evaporated under reduced pressure; methanol, excess H 2 S and HCl, as well as the mercaptoethyl C the rest is the starting dithioester, which has not changed. The two compounds are separated by fractional distillation. It should be noted, however, that the mixture thus prepared, i.e. 85 parts of dithio-valeric acid and 15 parts of ethyl dithiopentanoate, is well suited as an ore collection agent.

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Example 2

When it is desired to prepare dithioacetic acid having the same volatility as methanol, the latter is replaced by monoethyl ether of diethylene glycol. Therefore, 2000 ml of this ether are reacted with 23 g of sodium until the metal is completely dissolved; then saturating the solution with H S; then 0.95 mol of ethyl dithio-20 ° acetate CH CSSC H is added, and stirred for 18 h at 20 ° C.

3 2 5

The solution is then acidified with 200 ml of a solution of HCl in 5N anhydrous ether.

After filtration, the liquid is distilled under reduced pressure, first removing the ether and then recovering dithioacetic acid. The yield of this is 65%.

Example 3

Prepare a solution of 2 moles of dry NaSH per liter of dry methanol by saturating with H For methanol containing 1 mole of dry Na S. Saturation takes place at 2 + 2 ° C, followed by the addition of 2 moles of methyl dithiobutyrate CH CH CH CSS-CH. The mixture is then stirred for 3 h at 17 ° C. 130 ml of 10N HCl are then added and the precipitated NaCl is filtered off.

The filtrate is evaporated in vacuo to recover the methyl mercaptan CH SH and methanol formed.

3 The residue gives dithio-butyric acid CH CH CH CSSH with a yield of 3 2 2 of 87%.

Example 4 1 mole of dry Na S in 1 liter of ethylene glycol monomethyl 2 ether CH O-CH-CH-CH-OH is saturated with an excess of o 3 2 2 2 H 2 O at 0 ° C. 1 mole of methyl dithioacetate is then added and the operation is continued as in Example 2. A 63% yield of dithioacetic acid is obtained.

76261 4

Example 5

To a solution of 2 moles of NaSH and an excess of H 2 O in ethyl alcohol prepared as in Example 3 is added 2 moles of ethyl myristyl thia-1-dithioacetate, C H SCH CSSC H. The mixture is then stirred for 18 h, after which 120 ml of 10N HCl are added. The precipitated NaCl is separated off and distilled to give myristyl-thia-1-dithioacetic acid C H SCH CSSH 71% yield. This acid is 14 29 2 very useful for use in separating chalcopyrite or lead residue from ores.

Example 6

To a solution of 2 moles of NaSH in methanol prepared as in Example 3 is added 2 moles of ethyl dithiocaproate CH (CH) CSSC H. Work is continued 3 2 4 2 5 as in the previous examples. A 76% yield of dithiocaproic acid CH (CH) CSSH is obtained.

3 2 4

Example 7

Work as in the previous example, but using ethyl dithiolaurate instead of dithiocaproate; dithioluric acid CH (CH) CSSH gives a yield of 69%.

3 2 10

Example 8 2 moles of sodium ethanolate are dissolved in 1 liter of dry ethanol and treated by impregnation with H 5 at 5 ° C.

2

To the resulting solution is added 1 mole of ethyl tetrathiadipate C H -SSC-CH CH CH CH -CSSC H and the mixture is stirred for 20 h at 25 ° C at 18 ° C. The precipitated NaCl is then separated off and then fractionally distilled as in the previous examples.

Tetrathionadipic acid HSSC- (CH) -CSSH gives a yield of 67%.

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Examples 9-14

In accordance with the technique described on page 4 of FR patent 2,429,617, the effect of the collectors according to the present invention on a slurry of 3.3 g, at a pH of 5, per liter of various ores has been studied. The following results are obtained:

Recovered

Example Ore Collector% ore 9 Lead flour Dithiovaleric acid 95 from Example 1 10 Chalcopyrite - "- 94 11 Zinc low -" - 46 12 Lead flux Dithiolauric acid 91 13 Chalcopyrite - "- 96 13- Chalcopyrite Without builder 32 14 Zinc scavenger Dithiurine

Example 15

To a solution of 2 moles of NaSH in methanol prepared as in Example 3 is added 2 moles of carboxymethyl dithiobenzoate C H -CS -CH -CO H. The mixture is stirred. 2 2 for 16 h at 17 ° C. 120 ml of 10N HCl are then added and the precipitated NaCl is filtered off. The filtrate is evaporated in vacuo to give the thioglycolic acid and methanol formed. The residue is dithiobenzoic acid C H -CS H and 6 5 2 yield 85%.

Example 16 1 g of carboxymethyl vinyl 4-dithiobenzoate is suspended in a solution of 1 g of sodium in 50 ml of dry methanol, pre-saturated with hydrogen sulfide. (This solution may be replaced by a solution of an equivalent amount of 76261 6 sodium hydrogen sulphide in dry methanol saturated with hydrogen sulphide).

After one hour, the polymer has dissolved; stirring is continued for 6 h. Add concentrated inorganic acid and water; once the poly (vinyl-4-dithiobenzoic acid) has precipitated, it is identified by conventional spectroscopic methods.

Because it is very sensitive to oxidation of air, it must be precipitated using reactants and solutions carefully saturated with an inert gas. The following is the structural formula of this polymer: ^ V.

--CH2 --- CH-- · "I Jn (o)

CH2H

Various polymers have been obtained starting from carboxymethyl-vinyl-4-dithiobenzoate copolymers and styrene, methyl methacrylate, acrylamide, vinylpyrrolidone, methacrylic acid, etc. The above procedure is modified by adding other solvents to make the copolymer.

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Claims (6)

76261 A process for foaming ore, in particular lead, chalcopyrite and zinc flux, using a sulfur-containing substance as a collector, characterized in that a dithioic acid of the formula is used as the collector: RCS H 2 wherein R is alkyl or alkenyl having 4 to 20 carbon atoms, linear or branched, does not contain sulfur; or its sodium, potassium or ammonium salt. Process according to Claim 1, characterized in that R contains 6 to 18 carbon atoms. Process according to Claim 1, characterized in that the dithioic acid is selected from the group consisting of dithio-myristic, dithiopalmitic and dithio-oleic acids and their sodium, potassium and ammonium salts. Process according to Claim 1, characterized in that the dithioic acid is dithiovaleric acid or its sodium, potassium or ammonium salt. Process according to Claim 1, characterized in that the dithioic acid is dithiocaproic acid or its sodium, potassium or ammonium salt. Process according to Claim 1, characterized in that the dithioic acid is dithiolauric acid or its sodium, potassium or ammonium salt.