摘要
根据同时平衡原理和质量平衡原理，推导出Ｚｎ－Ｃｌ－－ＮＨ３－ＣＯ３２－－Ｈ２Ｏ系金属氧化物及碳酸盐在水溶液中热力学平衡的数学模型，计算并绘出该体系的浓度对数－ｐＨ图，研究了各配位体及ｐＨ值对该平衡体系的影响．当溶液有ＮＨ３和Ｃｌ－存在时，ＺｎＯ的溶解度增大；ＮＨ３的浓度对ＺｎＯ的溶解度的影响最大，因而不宜用氨水作为Ｚｎ２＋的沉淀剂．当溶液中有ＣＯ３２－存在时，Ｚｎ的溶解损失小；即使溶液中含有一些ＮＨ３，但溶液中Ｚｎ的总浓度还是比较小．当溶液中有ＣＯ３２－存在时不仅使Ｚｎ完全沉淀时的ｐＨ值降低了，而且ｐＨ值的范围也加宽了，因而可选用Ｎａ２ＣＯ３，（ＮＨ４）２ＣＯ３等作为Ｚｎ２＋的沉淀剂．根据溶液中［Ｃｌ－］Ｔ，［ＮＨ３］Ｔ，［ＣＯ３２－］Ｔ的不同，通过这些浓度对数－ｐＨ图可以在理论上初步选择Ｚｎ２＋沉淀的最佳ｐＨ值范围．
ccording to the law of conservation of mass and the law of simultaneous equilibrium,the mathematics model of ZnCl-NH3CO2-3H2O thermodynamic equilibrium system has been developed,and the logarithm concentrationpH(lgcpH) diagrams of this system have been made.The effect of ligands and pH value was studied and discussed.The dissolvability of ZnO will be increase when NH3 and Cl- exist in the solution.It is improper to use amonia as precipitator of Zn2+, because NH3 can obviously increase the dissolvability of ZnO.The loss by solution of Zn is little when CO2-3 exists in solution,even if some NH3 exists in it.The pH of zinc deposition shows decrease and the range of pH is widened when CO2-3 exists in the solution.So we can choose Na2CO3,(NH4)2CO3 etc as precipitators of Zn2+.According to the different T,T,[CO2-3]T, we can choose optimum pH range of zinc deposition in the theory.
出处
《中南工业大学学报》
CSCD
北大核心
1998年第2期193-196,共4页
Journal of Central South University of Technology(Natural Science)
基金
国家"八五"科技攻关计划基金
关键词
热力学平衡
ZNO
ZnCO3
NH3
热力学
锌
thermodynamic equilibrium
ZnO
ZnCO3
NH3
chloride/logarithm concentrationpH diagrams
