US1723295A - Process for flotation of ores - Google Patents

Description

. 15 ore body,

Patented Aug. 6, 1929.

PATENT OFFICE.

ADOLPHE H. NEY, OF NEW YORK, N. Y.

PROCESS FOR FLOTATION F ORES.

No Drawing.

This invention relates to a new and improved process for the concentration of ores by the method known as froth flotation and particularly to the use and employment in said ore concentration process, of chemicals and substances and transformation products thereof, hitherto unknown as being 0 advantage or utility as agents or assisting an auxiliary substances in said ore concentration process as customarily practiced. The process of concentrating ore, commonly designated froth flotation consists in producing by suitable means upon the surface of an aqueous suspension of a finely comminuted a froth. Under suitable conditions, this froth carries to the surface of the liquid, a concentrate containing a higher percentage of the metallic or other valuable constituents of the ore treated than it originally contained. T is concentrate is continuously or intermittently removed and further treated to recover and purify its valuable constituents.

A varietyof substances has been hitherto proposed and employed as agents or assisting and auxiliary media for producing the concentrating effect, or as they are called promoters and many of these substances are indeed effective in a greater or lesser degree in that their addition to or presence in the operation of flotation produces or effects the formation of a concentrate containinga higher percentage of the valuable constituents ofthe ore than the latter originally contained. The relative value of such flotation agents also depends on the amount necessary to be eifective, and the time required to produce such eflect, and their price.

Examples of such promoters are, for instance, the products of the reaction of an excess of disulphurdichloride upon certain aromatic amines, an

' able constitution:

R being a substituted aryl radical. These products may be consideredas the intramolecular anhydrides, or sultams, of a substituted thiosulphanic acid: R.S.S0.0H., R beposition by the amino group.

I have discovered that a group of comsponding sulphates,

d which have the proban aryl radical, substituted in the ortho-- sees the constitution:

Application filed May 2, 1927. Serial No. 188,397.

pounds closely related structurally to the above and hitherto not employed or proposed for thls purpose are very efiicient flotation agents. These compounds are derivatives of thiosulphuric acid HS:SO .OH-or its salts: l\IES.SO,.OMc, in which the hydrogen or metal-atom of the'sulphhydrate group: SH (SMe) is substituted by an organic radical. The prototype thiosulphate C .H .S.SO .ONa, has been discovered and described by Bunte, Berichte der deutschen chemischen gesellschaft, 7, (187 4;), 64:6 and he as well as later investigators have prepared and described other members of this group, such as n-propyl-, iso-butyl-, amylthiosulphate, as well as benzythiasulphate. Co1upare:ber.7 (1874;) 1162; (Spring) .-15. (1882). 1938; (Spring and Legros).25. (1892). 988-; 26 (1893) 993.996; (Otto and Rossing).-41 (1908) 1650; (A. Gutmann); 42 (1909) 228 (A. Gut1nann).-Trans. Chem. Soc. 91 (1907) 2021; 93 (1909). 1395, 1401; (Price and Slater) .Gazz. Chim. It.- 20, (1890). 25 (Pu'rgatti).

Representatives of these groups of compounds may be prepared by allowing an alkylor arylalkyl-halide, such as ethylbromide or benzylchloride to react upon sodiumthiosulphate in aqueous or aqueous-a1- coholic solution at temperatures from 30 C. to 100 C. In place of the halides the correas for example, sodiumethylsulphate or diethylsulphate may be used with equal success; also, the alkyland arylalkyl-radicals may be substituted withother groups such as the hydroxy-, alkyloxy-, carboxy-, sulpho-, amido-, cyan-, etc., group. If the alkyl group is-substituted by a further negative group, such as halogen, it is possible, according to the conditionsemployed, to replace either one or both of the negative groups by the thiosulphuric-rest, as for instance with ethylendibromide both: 1 Y

may be obtained without difliculty.

By allowing an organic acidhalide, such as benzoylchloride, acetylchloride, etc., to react in an analogous manner with sodiumthiosulphate, analogous compounds possessing similar properties may be obtained. They pos- R.C.O.S.SO,.ONa. R

indicating an alkyl, aryl or arylalkyl group,

. which may be substituted.dihalides of ditively.

By reacting the chlorides of organic sulphonic acids,for example paratoluosulphochloride with sodiumthiosulphate, bodies of similar properties having the probable constitution: R.SO .S.SO .ONa can be obtained.

Aromaticor purely aromatic-analoga of these compounds: R.S.S0.0Na and M050 S.R.SO .ONa, in which R a substituted arylgroup can also be obtained although by different reactions. Negatively substituted cyclic hydrocarbons such aschlorbenzol, do not react With sodiumthiosulphate barring certain exceptions.-Aromatic compounds capable of assuming, or possessing, quinoid character,

however, as a rule, smoothly react with thio-- sulphate under formation of substituted aromatic thiosulphates of the type:

a 7 NH, mu-c 11 S.SO .ONa

"Patent. 47 92 of 1900.

Similarly, benzoquinons, hydroquinons and their substitution products, especially chlorsubstitution products react under suitable conditions with one or several molecules of sodiumthiosulphate under formation of hydroquinone-monothiosulphate, hydroquinonedi-thiosulphate and hydroquinone-tetra-thiosulphate, which on oxidation yield the corresponding quinonemono or polythiosulphonic acid, or the corres onding di- 'or polysulphides. Compare: erman Patent. 175070.

These compounds are, in form of their alkali salts, in general, well crystallizing bodies, easily soluble in water and, though less readily, in alcohol. Under the influence of reducing agents, or even under the influence of hydrollzing agents, such as diluted mineral acid at the boil, they are transformed into the corresponding thiophenols, while upon treatment with oxidizing agents, they yield according to the nature of the oxidizing agent used and the experimental conditions dior polysulphides, presumably, for instance, according to the following equation:

2R.S.SO .ONa+O+H O= nssmeuanso may be substituted.The solubility of these compounds in water decreases with the increase of their molecular weight, as does their stability, evidenced by an increased tendency to conversion into disulphidic form.

' I have prepared a considerable number of members, of this class of compounds, for exfication according ample: sodiummethyl-, sodiumethyl-, sodium-n-propyl-, sodium-iso-propyl-, sodiumiso-butyland sodium-iso-amyl-thiosulphate, by the reaction of the corresponding alkylhalids or alkylsulphates upon thiosulphate, in several instances by both methods, and I have prepared benzylthiosulphate from benzylchloride and thiosulphate; I have also prepared the reaction products of sodiumthiosulphate with the following compounds: chloroacetic acid, glycerolmonochlorhydrinc, glyc erolmonochlorhydrine, glyceroldichlorhydrine, ethylendichloride (both one and both chlorinatoms replaced by the thiosulphate rest) benzolsulphochloride, paratoluolsulphochloride and malonylchloride. When subjected to flotation testsall these compounds were found to be excellent promoters, particularly sodiumethylthiosulphate, sodium-isopropylthiosulphate, and sodiumbenzylthiosulphate.

sodium-isobutyl-thiosulphate the following example is given:

Example.

600 grs. of a sulphidic copper bearing ore containing'1.2% copper were ground to fineness of #60 mesh with some water, 5 grs.

slaked lime and 0.25 grs. sodium-ethyl-thiosulphate added and the mixture transferred to a flotation cell, diluted and aeration started. Pine oil was added in drops as needed to produce frothing and the froth removed at intervals. Aeration was continued for 30 minutes, whereupon the collected froth was filtered and dried. It weighed, when dry, 67 grs. and contained 10% of copper; an ex traction of 93.2% of the copper present having thus been effected.

When replacing in parallel tests the sodium-ethyl-thiosulphate by similar amounts of sodium-isopropylthiosulphate, sodiumisobutylthiosulphate and sodium-benzylthiosulphate, results very closely approximating that described above were obtained.

It is understood that my invention is not limited to the proportions of materials given nor to the nature of subsidiary agents employed. Neither do I wish to be restricted to the use of any particular method or modus of working or operation, or to-any particular type of apparatus or machinery, all these things being capable of variation and modito the nature of the ore treated and the result desired. It is further to be understood that my invention is not limited to the compounds specifically mentioned herein, nor to those which I have actually examined as to their efficiency as fiotation agentsviz: 27 different compounds of this classbut I wish it expressly to be understood that my invention includes all and any I it by replacement of the hydrogen or metalgroup by an organic aving the constitu- R-S-fi-O-Me R being an organic radical, which may be substituted and may contain the thiosulphate rest a second time or more times.

Their general efficiency as promoters in ore flotation appears to be-and probably isdue in part to their tendency to assume under 'oxidative influences, disulphidic form.

When employing these compounds as flotation agents, it is not necessary that they be pure; excellent results, for instance, are obtained when the crude mixture obtained from the reaction of one molecule of sodiumthiosulphate and molecule of (liethylsulphate, consisting of approximately 70% sodiumethylthiosulphate and 30% sodiumsulphate, is used as flotation agent. It is evident that this point is of great importance in regard to the economy of the process, and cost of material. v

Having thus described the nature of my said invention and in what manner it may be applied, I declare that what claim is:

1. The method of concentrating ores by froth flotation which includes subjectingthe crushed mineral to a froth floating process I in the presence of a derivative of thiosul- "phuric acid, in which the hydrogen atom of the sulphydrate group is replaced by an alkyl group. r

2. The method of concentrating ores by froth flotation which comprises subjecting themineral in form of an alkaline pulp to a froth flotation operation in the presence of sodiumalkylthiosulphate and a suitable frothing agent.

3. The method of concentrating ores by froth flotation which comprises subjecting the mineral in the form of a pulp rendered alkaline with lime to a froth flotation operation in the presence of sodiumalkylthiosulphate and a suitable frothing agent.

In testimony whereof I affix my signature.

ADOLPHE H. NEY.