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ABSTRACT: BACKGROUND: Electrolytic manganese residues are the largest and most dangerous waste stream from the electrolytic manganese metal industry, and recovery of Mn from manganese residues is one of the main methods of recycling this waste. Bioleaching of electrolytic manganese residues for Mn extraction was investigated in this study.RESULTS: An extraction efficiency as high as 99.7% was achieved at 1% slag pulp concentration, 2320 mg L−1 extraction concentration and 80% extraction efficiency was attained at 8% slag pulp concentration, indicating the application potential of bioleaching in Mn extraction from manganese residues.CONCLUSION: The extraction of Mn from manganese residues depended exclusively on the non-contact mechanism. The acidic dissolution of soluble Mn2+ induced by sulfur-oxidizing bacteria resulted in 91.9% Mn extraction, while the reduction dissolution of insoluble Mn4+ by iron-oxidizing bacteria caused 5.8% Mn extraction. The combined action of sulfur-oxidizing bacteria and iron-oxidizing bacteria assured the maximum Mn extraction. EDS and XRD analysis of bioleaching residues further demonstrated the bioleaching mechanism involved. Copyright © 2011 Society of Chemical Industry
Journal of Chemical Technology & Biotechnology 03/2011; 86(6):832 - 837. · 2.17 Impact Factor
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ABSTRACT: Extraction of manganese from electrolytic manganese residues using bioleaching was investigated in this paper. The maximum extraction efficiency of Mn was 93% by sulfur-oxidizing bacteria at 4.0 g/l sulfur after bioleaching of 9days, while the maximum extraction efficiency of Mn was 81% by pyrite-leaching bacteria at 4.0 g/l pyrite. The series bioleaching first by sulfur-oxidizing bacteria and followed by pyrite-leaching bacteria evidently promoted the extraction of manganese, witnessing the maximum extraction efficiency of 98.1%. In the case of sulfur-oxidizing bacteria, the strong dissolution of bio-generated sulfuric acid resulted in extraction of soluble Mn2+, while both the Fe2+ catalyzed reduction of Mn4+ and weak acidic dissolution of Mn2+ accounted for the extraction of manganese with pyrite-leaching bacteria. The chemical simulation of bioleaching process further confirmed that the acid dissolution of Mn2+ and Fe2+ catalyzed reduction of Mn4+ were the bioleaching mechanisms involved for Mn extraction from electrolytic manganese residues.
Bioresource technology 11/2010; 102(2):1683-7. · 4.25 Impact Factor
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ABSTRACT: For fabrication human-eye comfortable LED street lighting sources, specific optical beam shaping systems with rectangular illumination distribution were designed based on non-imaging optics. Furthermore, thermal dissipation and high efficiency and reliability driving solutions were presented.
Nano-Optoelectronics Workshop, 2008. i-NOW 2008. International; 09/2008
