Patent GB-362927-A (GB)
Title: Improvements in or relating to ore concentration
IPC: B03D1/012
Filed: 1930-09-01
Abstract: Heterocyclic xanthic acid derivatives.--A xanthic acid derivative of a five atom heterocyclic ring substance four atoms of the ring being carbon, e.g. furan or thiophen, is used as a flotation agent in the froth flotation concentration of ores.  The following preparations are described:--(1) furfuryl xanthate either (a) by adding to furfuryl alcohol approximately molecular proportions of potassium or sodium hydroxide, then carbon disulphide and washing the crystalline product with ether, or (b) by adding carbon disulphide to a solution of furfuryl alcohol in ether in which metallic potassium has been dissolved; (2) an aqueous solution of the product of (1) (a) above is added to copper sulphate solution and a yellow precipitate obtained; simultaneously an oily liquid, probably a dixanthogen is formed with this precipitate; (3) an oily liquid is formed by treating the aqueous solution of the product of (1) (a) above with iodine; the addition of suitable lead or zinc salts also yields an oily liquid; (4) a strongly alkaline product containing furfuryl xanthate is obtained by grinding together molecular proportions of caustic potash, furfuryl alcohol and carbon disulphide and preventing the reaction from proceeding to completion.  The Specification as open to inspection under Sect. 91 (3) (a) is not limited to the use of xanthic derivatives of the five atom ring compounds and describes the preparation of a flotation agent by boiling together thiophen, sulphur chloride, and metallic zinc. This subject-matter does not appear in the Specification as accepted.ALSO:A xanthic derivative of a substance containing in its molecule a closed chain of five atoms, four of which are carbon, e.g. furan or thiophen, is used as a flotation agent in the froth flotation concentration of ores.  The following reagents are referred to: (1) furfuryl xanthate preferably prepared either (a) by adding to furfuryl alcohol in approximately molecular proportions first a solution of potassium hydroxide or sodium hydroxide and then carbon disulphide and washing the crystalline product with ether, or (b) by adding carbon disulphide to a solution of furfuryl alcohol in ether in which metallic potassium has been dissolved; (2) the precipitate obtained by adding an aqueous solution of the furfuryl xanthate prepared as described in (a) above to copper sulphate solution; (3) the oily liquid probably a dixanthogen formed simultaneously with the precipitate in reaction (2) above; (4) the oily liquid formed by treating the aqueous solution of the product obtained in reaction (1) (a) above with iodine; (5) a strongly alkaline product containing furfuryl xanthate obtained by mixing caustic potash, furfuryl alcohol, and carbon disulphide and preventing the reaction from proceeding to completion. Examples are given of the flotation treatment of copper ores, including mixed sulphide and oxidized copper ores, zinc ores, and lead ores and of two stage treatments for the differential flotation of copper and zinc in copper-zinc ores and of lead and zinc in lead-zinc ores, both of which may contain silver which is also recovered, using one of the reaction products described above, an oil, and various modifying agents, e.g. lime, soda, sodium cyanide, zinc or copper sulphate, or sodium silicate.  The Specification as open to inspection under Sect. 91 (3) (a) is not limited to the use of xanthic derivatives of the five atom ring compounds and describes the preparation of a flotation agent by boiling together thiophen, sulphur chloride, and metallic zinc. This subject-matter does not appear in the Specification as accepted.