(1. 东北大学 材料与冶金学院,沈阳 110819;
2. 东北大学 多金属共生矿生态化利用教育部重点实验室,沈阳 110819)
摘 要: 通过热力学计算,得到ZnS-H2O系各物质高温条件下的GΘ值、φΘ值或pHΘ值以及各反应对应的电位表达式,分别绘制出不同离子活度、不同氧分压条件下的φ—pH图。由φ—pH图可以看出,随着离子活度的增大,S与Zn2+稳定区逐渐增大,但构成稳定区各反应的pH值上下限范围逐渐减小;随着氧分压的增大,水的稳定区逐渐增大。对ZnS进行了氧压浸出实验研究,采用全谱直读等离子光谱仪(ICP)、XRD和XRF等方法对浸出液和浸出渣进行分析、表征。结果表明:当初始酸浓度为15%、氧分压为1.1 MPa、浸出温度为160 ℃、液固比为8:1、浸出时间为90 min、搅拌速度480 r/min时,锌的浸出率为98.86%,硫的转化率为81.33%。实际结果与根据φ—pH图理论计算结果吻合。
关键字: 氧压浸出;ZnS-H2O系;φ—pH图;氧分压;离子活度
(1. School of Materials and Metallurgy, Northeastern University, Shenyang 110819, China;
2. Key Laboratory of Ecological Utilization of Multi-metal Intergrown Ores, Ministry of Education,
Northeastern University, Shenyang 110819, China)
Abstract:The values of GΘ, φΘ or pHΘ and relevant potential expressions were obtained through thermodynamical calculation, and φ—pH figures of ZnS-H2O system at different ionic activities and different oxygen partial pressures were obtained. With increasing the ionic activity, the stable regions of S and Zn2+ in the φ—pH figures become gradually large, but the limit of pH in the stable region becomes gradually small. With increasing the oxygen partial pressure, the stable region of H2O become large. The oxidative pressure leaching experiments of ZnS were done in autoclave, the leaching solution and leaching slag were characterized by inductively coupled plasma-atomic emission spectrometry (ICP), XRD and XRF. The results indicate that when the sulfuric acid concentration is 15%, oxygen partial pressure is 1.1 MPa, leaching temperature is 160 ℃, liquid-solid ratio is 8׃1, leaching time is 90 min and stirring rate is 480 r/min, the leaching rate of zinc is 98.86% and the conversion rate of sulfur is 81.33%. The experiment results well accord to the calculation results of φ—pH figures.
Key words: oxidative pressure leaching; ZnS-H2O system; φ—pH figure; oxygen partial pressure; ionic activity