SELECTIVE FLOTATION OF CHALCOPYRITE AND PYRITE AND THE EFFECT OF ORE TYPE

摘要

The depression of pyrite in the selective flotation of complex sulfide ores is a common problem associated with a number of deposits throughout the world. Mineralogical differences often prevent pyrite depression systems that have been optimized for a particular deposit from being successfully applied to another. Investigations were carried out to establish the link between ore deposits and the differential flotation behavior of chalcopyrite and pyrite. Differential flotation tests were performed on copper ores from five different locations in Australia (A, B, C, D) and North America (E). Flotation tests used the copper selective collector ethyl isopropyl thionocarbamate and the pyrite depressants lime-cyanide and sodium metabisulfite. The pulp potential in the rougher was monitored continuously using mineral electrodes constructed from pure specimens of chalcopyrite and pyrite. Water analyses were performed on selected flotation tests to identify differences in solution chemistry that may be affecting the performance of a particular depressant. Optimum flotation selectivity for four of those ores tested (A, B, D, E) was obtained using 6 mg/l sodium cyanide and 500 g/t lime. Selectivity for ore C was optimum using 500 g/t sodium metabisulfite. Flotation selectivity and chalcopyrite recovery were found to drop dramatically with depressant concentrations above 6 mg/l cyanide and 500 g/t metabisulfite. It is believed that these differences in flotation selectivity between ores are related to differences in mineral reactivity between deposits.