Thermodynamic Analysis of Alkaline Leaching of Solid Wastes Bearing Zinc
For the hydrometallurgical processing of solid wastes bearing zinc by alkaline leaching, the E-pH equilibrium diagrams of the systems every component were drawn according to thermodynamics calculation. ZnO, ZnCO3 and Zn2SiO4 were the predominant mineralogical phases in solid wastes bearing zinc. According to diagrams, ZnO, ZnCO3 and Zn2SiO4 can be dissolved by strong alkaline solution. Compared with ZnO and ZnCO3, higher concentration of OH－ was required to dissolve Zn2SiO4. In strong alkaline solution, most of zinc ions exist in the form of Zn(OH)4 2－. The apparent equilibrium constant (KC) for reaction of ZnO dissolved in NaOH solution was investigated. It has been found that KC increased with the NaOH concentration increasing up to 4.2 mol/L. The KC dropped down when sodium hydroxide is over 5mol/L because the high sodium hydroxide concentration increased the viscosity of the solution, which would tend to reduce the diffusion rate of the ions. Thus, a NaOH solution of 4-5 mol/L(160-200g/L) was considered suitable for leaching reaction.
Cheng-long ZHANG Jing-wei WANG Jian-feng BAI You-cai ZHAO
School of Urban Development and Environmental Engineering, Shanghai Second Polytechnic University,Sh State Key Laboratory of Pollution Control and Resource Reuse, Tongji University, Shanghai, China, 20
国际会议
The Fifth International Conference on Waste Management and Technology(第五届固体废物管理与技术国际会议)
北京
英文
646-648
2010-11-01（万方平台首次上网日期，不代表论文的发表时间）