氢氧化钠分解钼酸铅矿的热力学分析  

Thermodynamics analysis on sodium hydroxide decomposition of wulfenite

作　　者：张刚[1] 赵中伟[1] 李江涛[1] 陈爱良[1] 霍广生[1] 李洪桂[1] 

机构地区：[1]中南大学冶金科学与工程学院,湖南长沙410083

出　　处：《中南大学学报（自然科学版）》2008年第5期902-906,共5页Journal of Central South University:Science and Technology

基　　金：国家"863"计划资助项目(2006AA06Z122);湖南省国土资源厅矿产资源与合理开发利用科研专项计划资助项目(2006K06)

摘　　要：针对钼酸铅矿的氢氧化钠分解过程,根据电荷平衡和质量平衡的原理,运用热力学数据绘制25℃时Pb-Mo-H2O系组分的浓度对数-pH图。利用热力学平衡图对氢氧化钠分解钼酸铅矿的工艺条件进行讨论。研究结果表明:整个pH值范围内可分为3个物质稳定区,即pH<6.17时为H2MoO4的稳定区;6.17<pH<11时为钼酸铅的稳定区;pH>11时为Pb(OH)2的稳定区,在该范围内随着pH值升高,当Pb(OH)2达到过饱和时,溶液中开始析出Pb(OH)2沉淀,从而实现钼酸铅的碱分解过程。通过对Pb-Mo-H2O系的热力学分析,苛性钠分解彩钼铅矿在一定的pH值下是可行的,但在碱分解过程中Pb2+与羟基形成了配合物,主要是以Pb(OH)3-的形式存在而大量进入溶液,因此,尚需进一步除铅。According to the law of charge balance equilibrium and the law of conservation of mass, the logarithm concentration-pH diagram of Pb-Mo-H2O system was established on the basis of thermodynamic data at 25℃. Thermodynamic analysis was carried out to show the effect of technical conditions on sodium hydroxide decomposition of wulfenite. The results show that the whole pH value of the system is divided into three areas. The first one is the stable area of H2MoO4, which is located in the range of the pH value less than 6.17. The second area is the stable area of PbMo04, which is located at the pH value from 6.17 to 11. The third one is located in the range of the pH value higher than 11, which is the stable area of Pb（OH）2. In the third area, Pb（OH）2 is gradually supersaturated in solution with the increase of pH value, so the Pb（OH）2 is deposited as sediment. As a result, the processing of wulfenite leaching by sodium hydroxide is carried out. Additionally, feasibility of the processing of wulfenite leaching by sodium hydroxide is proved, but Pb^2＋ reacts with hydroxyl to form complexes which is leached into solutions. So removing the complexes lead from solution is needed.

关 键 词：钼酸铅矿 热力学 浓度对数-pH图 氢氧化钠 

分 类 号：TF111.31[冶金工程—冶金物理化学]