title: Analysis of reasons for decline of bioleaching efficiency of spent Zn-Mn batteries at high pulp densities and exploration measure for improving performance.
abstract: The reasons for decline of bioleaching efficiency of Zn and Mn from spent batteries at high pulp densities were analyzed; the measures for improving bioleaching efficiency were investigated. The results showed that extraction efficiency of Zn dropped from 100% at 1% of pulp density to 29.9% at 8% of pulp density, with Mn from 94% to only 2.5%. It was almost the linear reduction of the activity of the sulfur-oxidizing bacteria with increase of pulp density that witnessed declined bioleaching efficiency of Zn; it was the complete inactivation of the iron-oxidizing bacteria at 2% of pulp density or higher that witnessed declined bioleaching dose of Mn. By means of reducing initial pH value of leaching media, increasing concentration of energy matters and exogenous acid adjustment of media during bioleaching, the maximum extraction efficiency of almost 100% for Zn and 89% for Mn at 4% of pulp density was attained, respectively.
authors.affiliation: School of Chemical Engineering and Environment, Beijing Institute of Technology, Beijing 100081, PR China. xinbaoping@bit.edu.cn
authors.forename: Baoping
authors.initials: B
authors.lastname: Xin
authors.forename: Wenfeng
authors.initials: W
authors.lastname: Jiang
authors.forename: Xin
authors.initials: X
authors.lastname: Li
authors.forename: Kai
authors.initials: K
authors.lastname: Zhang
authors.forename: Changhao
authors.initials: C
authors.lastname: Liu
authors.forename: Renqing
authors.initials: R
authors.lastname: Wang
authors.forename: Yutao
authors.initials: Y
authors.lastname: Wang
mesh_terms: D001419:Bacteria / Q000254:growth & development / Q000378:metabolism*; D001673:Biodegradation, Environmental; D015169:Colony Count, Microbial; D011211:Electric Power Supplies; D052918:Environmental Restoration and Remediation / Q000379:methods* / Q000592:standards*; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008345:Manganese / Q000302:isolation & purification*; D010100:Oxygen; D013052:Spectrometry, X-Ray Emission; D013997:Time Factors; D014961:X-Ray Diffraction; D015032:Zinc / Q000302:isolation & purification*
chemical_list: D008345:Manganese; D015032:Zinc; D010100:Oxygen