Intensified bioleaching of chalcopyrite by communities with enriched ferrous or sulfur oxidizers

Abstract

The chalcopyrite bioleaching by enriched ferrous or sulfur oxidizers was investigated. The bioleaching was also intensified three times by the enriched communities. The results indicated that copper recoveries extracted by the enriched ferrous and sulfur oxidizers (Fe-O and S-O) were 38.87% and 43.13%, compared with that by the original community (35.35%). The positive effects of re-introducing S-enriched community to Fe-O and S-O groups were observed with copper extraction rates up to 41.67% and 46.45%. CCA indicated that the community dynamics intensified by S-enriched community was closer to that of the no re-inoculated one, but the Fe-enriched community drove a great fluctuation. A mechanism model for S-enriched community intensifying chalcopyrite bioleaching was proposed. More sulfur oxidizers in community slowed down jarosite formation and maintained lower ORP, which was propitious to chalcopyrite dissolution. Meanwhile, they accelerated S0 decomposition and decreased pH, which promoted acid leaching of chalcopyrite at a low cost.