Influence of grinding method on complex sulphide ore flotation: a pilot plant study

Abstract

The present work deals with pilot plant investigations on the influence of conventional- and autogenous grinding methods in the flotation of a complex sulphide ore. The study includes the investigation of the particle size and shape analysis and the pulp chemical measurements — E h, pH, O 2, concentration of cations and anions, at several stages of the grinding and flotation circuits. The rougher flotation concentrates of the Cu-Pb and Zn circuits were analysed to evaluate the flotation behaviour of chalcopyrite, galena and sphalerite. The results indicate better liberation of minerals in coarse size fractions for the pulp ground by autogenous mill while conventional grinding shows higher degree of liberation in the fine size range. Metallurgical analyses of the final flotation concentrates shows higher recoveries of Cu, Pb and Zn for the pulp ground by autogenous milling. The grades of Cu and Pb were better with conventional grinding but the recoveries were less than those obtained by autogenous grinding. Several interesting observations concerning pulp chemistry (e.g. the concentration of Fe ions is lower in pulps ground by conventional method than by autogenous means!) are discussed.