GB515937A - Improvements in or relating to the concentration of minerals by froth flotation - Google Patents

Abstract

515,937. Concentrating minerals. MINERALS SEPARATION, Ltd. June 3, 1938, Nos. 16754 and 16755. Convention dates, June 5, 1937, and Dec. 18, 1937. [Class 82 (ii)] [Also in Group III] A xanthomolybdic acid compound is used as a collecting agent in the froth flotation concentration of minerals. The compound, which can be employed in conjunction with other collectors such as xanthates and dithiophosphates, is prepared by acidification of a solution of a xanthate and a molybdate, the preferred proportions corresponding to 2 molecules of xanthic acid to 1 of molybdic acid. The xanthomolybdic acid compound is precipitated as an oil which solidifies on standing ; it may be purified by solution in ammonia and reprecipitation with acid. The compound may be added in the solid form to the ore during grinding or to the pulp as a solution in an organic liquid such as acetone, chloroform, or ether, or the mixture obtained on acidification of the xanthate-molybdate solution may be added. The concentration of the following ores is described, a xanthomolybdic acid compound being used in each case in addition to the reagents specified :-(1) copper ores using pine oil and lime ; (2) lead ores using soda ash and cresol; zinc ores using copper sulphate and pine oil ; gold and silver ores using pine oil and cresol; molybdenum ore using sodium cyanide and terpineol. In the concentration of a copper-molybdenum ore a copper concentrate is first obtained by using cresol and xanthate with a depressing agent such as starch or other protective colloid to inhibit flotation of molybdenite ; the tailings are then subjected to flotation with pine oil and a xanthomolybdic acid compound to give molybdenite concentrate which is cleaned by refloating with cyanide and pine oil. In the treatment of mixed sulphideoxide copper ores the sulphides may be floated by the use of the xanthomolybdic acid compound and pine oil, the remaining pulp being thickened, leached with sulphuric acid to dissolve the oxide copper which is then precipitated as metallic copper by addition of iron and floated with pine oil, Barrett oil, and the xanthomolybdic acid compound. Alternative treatments comprise (a) removing the oxide copper by leaching and filtering prior to flotation, and (b) dissolving the oxide copper by treatment with sulphuric acid, precipitating by adding iron, and floating the sulphide copper and metallic copper together. Specification 223,860, [Class 82 (ii)] and U.S.A. specification 2,070,076, are referred to.