Bioleaching of a Complex Co-Ni-Cu Sulfide Flotation Concentrate by Bacillus megaterium QM B1551 at Neutral pH

ABSTRACT

Bioleaching of sulfide minerals at neutral pH has been rarely reported. In this study, a bacterium, Bacillus megaterium QM B1551, was isolated from Jinchuan sulfide tailings and used to leach a complex sulfide flotation concentrate for the extraction of Co²⁺, Ni²⁺ and Cu²⁺ at near neutral pH. A total of 38.2% Co, 44.7% Ni and 3.6% Cu were extracted from the sulfide concentrate in 5 days with an initial pH of 6. An enhanced Co²⁺, Ni²⁺ and Cu²⁺ extraction extent was achieved by first bioleaching the concentrate with Bacillus megaterium QM B1551 at 35°C and then followed by chemical leaching with 4 M sulfuric acid at 90°C. As a result, a total of 60.7% Co²⁺, 76.3% Ni²⁺ and 39.8% Cu²⁺ were extracted. On an industrial scale, the profits from the metal recovery by such a combined leaching procedure are optimum if considering the cost-benefit ratio.

KEYWORDS:

• Bacillus megaterium QM B1551
• bioleaching
• complex sulfide concentrate
• Bioleaching-chemical leaching

Acknowledgments

Xinglan Cui and Xin Wang contributed equally to this work. The authors really appreciated the two reviewers' comments on the manuscript, which greatly improved this manuscript. The authors were also very grateful to beamline BL14B at Shanghai Synchrotron Radiation Facility for providing the beam time.

Funding

This research is supported by National Basic Research Program of China (973 program, No. 2014CB846001), the Key Project of the National Natural Science Foundation of China (Grant No. 41230103) and the National Natural Science Foundation of China (Grant No. 41272003, No. 41402301 and No. 41402032).