A Study of Flotation and Leaching Behaviour of Bornite and Chalocpyrite
MetadataShow full item record
This study was carried out to investigate the flotation and leaching behaviour of bornite and chalcopyrite when they are together as principal sulphide minerals. Bench scale flotation performance was examined both in the absence and in the presence of a collector, PEX. In the absence of a collector, chalcopyrite floated significantly better than bornite. In the presence of a collector there was a reversal in selectivity, with bornite recovery presiding over that of chalcopyrite. Chalcopyrite recovery was marginally improved from the collectorless flotation case while bornite experienced vastly improved recoveries in the presence of a collector to surpass the recovery of chalcopyrite. The gap between floatability of bornite and chalcopyrite became more prominent under oxygen-deficient conditions induced by nitrogen flotation, which significantly decreased flotation rate of both minerals, but the floatability of bornite was still much higher than that of chalcopyrite. It is suggested that galvanic interactions promote the interaction of bornite with a collector while retarding interactions of chalcopyrite with the collector. Collectorless flotation of chalcopyrite observed under oxidizing conditions using air is thought to be prevalent even in the presence of a collector obscuring the selectivity of the process. Leaching of the mixtures of bornite and chalcopyrite at mass ratios of 1:1, 1:3 and 3:1 are performed under various conditions to investigate the possible changes in leaching behaviour in relation to galvanic interactions. Leaching at 90°C in the presence of 0.1 M ferric ions in 0.1 M sulphuric acid provided the best results with 90% copper extraction from the mixtures in 6 hours. Observed copper extractions suggested increased copper extraction from chalcopyrite with this approach. The introduction of cupric and ferrous ions into solution, together with variation of solution potential made it difficult to assess in details on the effects of galvanic interactions due to these parameters being known to improve copper extraction from chalcopyrite. Galvanic interactions together with the presence of cupric ions were held mainly responsible for the increased copper extraction.