GB515592A - Improvements in or relating to the separation of minerals - Google Patents

Abstract

515,592. Concentrating ores. SMIDTH & CO. AKTIESELSKABET F. L. June 8, 1938, No. 17051. Convention date, Sept. 10, 1937. [Class 82 (ii)] In the froth flotation separation of minerals from carbonaceous ores, i.e. ores which contain graphite or other carbonaceous matter, the flotation of the carbonaceous constituents is prevented or reduced by the addition, as a depressing agent, of a lignum sulphonate such as calcium or sodium lignin sulphonate. The pulp is preferably conditioned with the depressing agent prior to the addition of the collecting and frothing agents. The process is particularly applicable to the concentration of carbonaceous precious metal ores and carbonaceous limestones &c. The usual collecting agents may be used, e.g. xanthates for sulphide minerals, and fatty acids, their mixtures with fuel oil, fatty acid soaps and emulsions, fatty acid and rosin acid mixtures, saponified tall oil, and positive ion agents, for oxidized ores. The concentration of a carbonaceous pyritic gold ore is described, the reagents used being calcium lignin sulphonate and one or more of pine oil, secondary butyl xanthate, copper sulphate, soda ash, and alkyl dithiophosphate. Products suitable for cement manufacture may be obtained by froth flotation of the calcite from a carbonaceous argillaceous limestone, calcium or sodium lignin sulphonate being used in conjunction with oleic acid, a frother consisting of a mixture of branched and straight chain aliphatic monohydric alcohols obtained, together with methanol, by catalytic hydrogenation of carbon oxides, and, in some cases soda ash. In an alternative method the aluminium silicates may be floated from the calcite by using in conjunction with the lignin sulphonate and the frother a positive ion agent, giving in solution a positive ion containing an aliphatic hydrocarbon group of at least 8 carbon atoms, e.g. dodecyl amine hydrochloride or a mixture of the hydrochlorides of the amines in which the alkyl groups correspond to the fatty acids in coconut oil. If desired, the ore pulp may first be subjected to froth flotation without the addition of a depressing agent for the carbonaceous matter, the concentrate containing the carbonaceous matter being then refloated in the presence of a lignin sulphonate. Specifications 515,608 and 515,609 are referred to.