AN ASSESSMENT OF INFLUENCE OF SELECTED CHARACTERISTICS OF FEED ON THE RESULTS OF BALL MILL GRINDING PROCESS COURSE FOR POLISH COPPER ORES

Abstract

The article concerns issues related to the copper ore ball mill grinding process, operating at different technological parameters. The aim of the study was to investigate the influence of various operating parameters and feed characteristics on selected technological effects (comminution degree, yields of the finest particle size classes, ready for downstream flotation operations). The research program included grinding tests of two lithological types of Polish copper ore (dolomite and sandstone) and their mixtures in the proportions: 70% dolomite +30% sandstone and 30% dolomite +70% sandstone. Material was treated under wet and dry grinding in Bond’s ball mill. Three different grinding time were applied together with three levels of mill’s rotational speed. The feed material with three different particle size compositions was used in the rests. The results show that increases in yields of fine particle size fractions for each sample are dependent on the particle size composition of feed, grinding time and rotational speed of mill. Together with increasing of grinding time, fine particle size fraction contents increase too, especially for the coarse feed without fine particles. In general, higher comminution degrees were obtained for ore mixtures, the most favorable results for a mixture of 30% sandstone +70% dolomite, where S 50 equaled 358 and S 90 = 178. Correlation analysis showed that in fact all technological parameters under investigation were significantly related to the obtained comminution effectiveness.