Thermodynamic analysis and process optimization of zinc and lead recovery from copper smelting slag with chlorination roasting

从氯化焙烧铜熔炼渣中回收锌和铅的热力学分析及工艺优化

An efficient chlorination roasting process for recovering zinc(Zn)and lead(Pb)from copper smelting slag was proposed.Thermodynamic models were established,illustrating that Zn and Pb in copper smelting slag can be efficiently recycled during the chlorination roasting process.By decreasing the partial pressure of the gaseous products,chlorination was promoted.The Box−Behnken design was applied to assessing the interactive effects of the process variables and optimizing the chlorination roasting process.CaCl_(2) dosage and roasting temperature and time were used as variables,and metal recovery efficiencies were used as responses.When the roasting temperature was 1172℃ with a CaCl_(2) addition amount of 30 wt.%and a roasting time of 100 min,the predicted optimal recovery efficiencies of Zn and Pb were 87.85%and 99.26%,respectively,and the results were validated by experiments under the same conditions.The residual Zn-and Pb-containing phases in the roasting slags were ZnFe_(2)O_(4),Zn_(2)SiO_(4),and PbS.

提出一种高效回收铜熔炼渣中Zn、Pb金属的氯化焙烧工艺。建立可揭示氯化焙烧过程中有效回收Zn、Pb的热力学模型。通过减小气相产物分压,可以促进氯化焙烧反应。选取CaCl_(2)用量、焙烧温度和时间作为工艺变量,Zn和Pb的回收率作为响应,采用Box−Behnken设计评估各工艺变量间的相互作用关系,优化氯化焙烧工业。最佳工艺条件为CaCl_(2)用量30%(质量分数)、焙烧温度1172℃和焙烧时间100 min,在此条件下,锌和铅的回收率分别为87.85%和99.26%,该结果与实验结果相吻合。焙烧渣中存在ZnFe_(2)O_(4)、Zn_(2)SiO_(4)和PbS含Zn、Pb相。