GB373663A - Improvements in or relating to the flotation concentration of minerals - Google Patents

Abstract

Carbon oxy-sulphide is prepared by passing carbon monoxide and sulphur vapour through hot clay or porcelain tubes or by subjecting the mixture to electrical discharge; or, on a small scale, by the action of sulphuric acid on potassium sulphocyanide, the product being purified by passing it through string caustic soda solution and sulphuric acid.ALSO:Compounds of the structure ROC : OSM where R is a hydrocarbon radical and M is hydrogen, a metal, or another ROC : OS group are used in the flotation concentration of ores. The compound may be an alkyl monothiocarbonate which may be prepared by passing carbon oxysulphide into a solution of a caustic alkali, (e.g. potassium hydroxide), in the desired aliphatic alcohol. Disulphides are obtained by the action of potassium ferricyanide on an alkyl monothiocarbonate, e.g. by the action of potassium ferricyanide on potassium ethylmonothiocarbonate dicarbethoxy - disulphide is obtained.ALSO:In the flotation concentration of ores there is added to the pulp a compound of the structure ROC : OSM where R is a hydrocarbon radical and M is hydrogen, a metal, or another ROC : OS group. The compound may be an alkyl mono-thio-carbonate or a disulphide of the structure ROC : OS : SO : COR, substances specifically refined to being derivatives of ethyl, amyl, butyl, benzyl, or cyclohexyl mono-thio-carbonic acid, e.g. potassium ethyl mono-thio-carbonate and the disulphide obtained by treating this compound with potassium ferricyanide and known as ethyl carbonic acid disulphide or dicarbethoxy disulphide. Examples are given of the use of one of the above reagents in the concentration of copper minerals from copper iron ores in neutral, acid, or alkaline suspension with cresol or pine oil as frothing agent; of copper from oxidized copper ores using coal tar creosote and pine oil as frothing agent; of lead and zinc from their respective ores; of gold and silver from an ore containing both these metals; and in the treatment of lead-zinc and copper-zinc ores in both of which cases a concentration is first carried out with cresol as frothing agent and with sodium carbonate, sodium cyanide and zinc sulphate as modifying agents to separate the lead and copper respectively, the zinc being then recovered by a second concentration using creosote, pine oil and copper sulphate. The alkyl mono-thio-carbonates are prepared by passing carbon oxy-sulphide into a solution of a caustic alkali, e.g. potassium hydroxide, in the alcohol containing the desired hydrocarbon radical. Carbon oxy-sulphide is prepared by passing carbon monoxide and sulphur vapour through hot clay or porcelain tubes or by subjecting the mixture to electrical discharge; or, on a small scale, by the action of sulphuric acid on potassium sulphocyanide, the product being purified by passing it through strong caustic soda solution and sulphuric acid. Specification 294,921, [Class 82 (ii), Washing granular &c.], is referred to.