Nuclear chemistry

Metallurgy

Materials science

Bioleaching

Copper extraction techniques

Dissolution

Physical chemistry

Chalcopyrite

Environmental chemistry

Sulfur

Chemistry

Copper

In nature, sulphide minerals are the main sources for extraction of some metals for industrial uses, such as copper, lead, zinc and nickel. One of the most important and explored copper sulphide is chalcopyrite, being the most abundant copper mineral in nature. Metals can be extracted using microorganisms, leading the bioleaching to an economic and environmentally sustainable process. In this research, it was developed different iron and sulfur oxidizer consortium to promote chalcopyrite (CuFeS2) solubilization. All consortium were obtained from previous enrichment in a specific culture of 15 ore samples provided by Companhia Vale S.A. Four iron oxidizer and four sulfur oxidizer consortium were prepared, and named Dep SOS-4, S3A, SO3 and D1. X ray diffraction of the Dep SOS-4 and S3A samples showed mainly quartz content (SiO2), whereas the SO3 and D1 samples showed covellite (CuS), pyrrothite (FeS), chalcopyrite (CuFeS2) and sulfur (S) presence too. The iron oxidizer consortium were adapted to grow with chalcopyrite and then used in shake flasks experiments with chalcopyrite. A mix of consortiums was performed, but without a previous adaptation to the chalcopyrite. The Eh values increased during the bioleaching of the inoculated flasks, stabilizing around 550 mV, which affects metal solubilization due to an increase in the Fe/Fe ratio. The iron oxidizer consortium resulted in a better dissolution of the chalcopyrite when compare with the control, sulfur oxidizer consortium and pure strain At. thiooxidans FG01. However, it was not observed any significant difference between the consortium and At. ferrooxidans LR in the chalcopyrite dissolution. In the respirometric tests with chalcopyrite as substrate were observed lower consumption of oxygen to the iron oxidizer consortium (Dep SOS -4, S3A, SO3 and D1) in relation to At. ferrooxidans LR. Higher oxidation activity was observed for both consortium and pure strain when the substrate was changed to Fe. Verifying the rDNA bands using DGGE gel analysis, it was observed that all bands from iron oxidizer consortium were similar to the pure strain At. ferroxidans LR bands and, sulfur oxidizer consortium bands were similar to the pure strain At. thiooxidans FG01.

UNESP-UNIVERSIDADE ESTADUAL PAULISTA CAMPUS DE ARARAQUARA PROGRAMA DE PÓS-GRADUAÇÃO EM BIOTECNOLOGIA CONSÓRCIOS MICROBIANOS ASSOCIADOS A AMBIENTES DE MINAS: OBTENÇÃO, AVALIAÇÃO FISIOLÓGICA E MOLECULAR