GB471861A - Improvements in and relating to froth flotation agents - Google Patents

Abstract

A thiocarbanilide derivative which is very finely divided and more soluble in water than thiocarbanilide itself is precipitated by mixing water with a solution of thiocarbanilide in sulphuric acid. The product, which is used as a froth flotation reagent, may be separated from the acid and used in the dry state or made into a sludge with water, or may be used as a sludge or a suspension in the dilute acid solution from which it is precipitated. The derivative may be precipitated on an inert insoluble carrier such as diatomaceous earth.ALSO:A froth flotation reagent is prepared by dissolving thiocarbanilide in sulphuric acid and mixing the solution with water to precipitate a derivative which is very finely divided and is more soluble in water than thiocarbanilide itself. The precipitate may be separated from the acid and used in the dry state or made into a sludge with water, or may be used as a sludge or a suspension in the dilute acid solution from which it is precipitated. Alternatively, the acid solution may be added direct to the pulp, the water in the pulp causing precipitation of the derivative. The derivative may be precipitated on an inert insoluble carrier such as diatomaceous earth which may be added to the pulp either dry or as a sludge. The concentration of various mixed sulphide ores is described. A mixed lead and copper concentrate may be obtained from an ore containing lead, copper, zinc, and iron sulphides either by direct flotation with a mixture of the thiocarbanilide derivative and cresol, or by adding sodium cyanide which depresses the zinc and iron and part of the copper, adding sulphuric acid to reactivate the copper, and then floating with the derivative and cresol. A lead-zinc-iron ore may be floated with the derivative, cresol, and sodium hydroxide with or without sodium cyanide to give a lead concentrate, the zinc being then floated, using copper sulphate and derivative, and the iron, if desired, being finally floated with xanthate. A copper-zinc-iron ore may be treated with sodium cyanide or zinc cyanide to depress the zinc and iron and, in part, the copper, and a solution of this carbanilide in concentrated sulphuric acid then added. The derivative is precipitated and the copper is reactivated by the sulphuric acid and can then be floated with the addition of a frothing agent. Alternatively, the sulphuric acid and the derivative may be added separately.