利用逆流氯化法从锌浸渣中浸出铅

Leaching lead from zinc leaching residue by countercurrent chlorination

研究了逆流氯化法在锌浸出废渣提铅中的应用,即利用CaCl2将不可溶的含铅相转变为PbCl2。通过考察氯化钙浓度、浸出温度、浸出时间、液固比和pH对锌浸渣中铅提取的影响,明确浸出过程的主要因素。研究结果表明,锌浸渣中的铅以PbSO4形式富集,回收价值高。对比5个因素的影响,浸出时间和pH对铅提取的作用较小。以铅质量分数14.14%的锌浸渣为研究对象,确定了适宜的工艺条件:氯化钙浓度为3.15 mol/L,浸出温度为45℃,浸出时间为120 min,液固比为6∶1,pH值为2,铅的浸出率可以达到85.78%。此外,动力学研究表明,锌浸渣中铅的浸出受内扩散控制,表观活化能为17.59 kJ/mol。

The application of countercurrent chlorination method in lead extraction from zinc leaching residue was studied,in which the insoluble lead-containing phase was directly transformed to PbCl2 by using CaCl2.By investigating the effects of calcium chloride concentration,leaching temperature,leaching time,liquid-solid ratio and pH on the extraction of lead from zinc leaching residue,the main factors were clarified.The results show that,lead in zinc leaching residue is enriched in the form of PbSO4,thus it has high recovery value.Among the five factors,effects of leaching time and pH on lead extraction were small.Taking zinc leaching residue with a lead mss fraction of 14.14% as research object,the appropriate process conditions were determined as,concentration of calcium chloride 3.15 mol/L,leaching temperature 45℃,leaching time 120 min,liquid-solid ratio 6∶1 and pH 2,and the extraction of Pb can reach 85.78%.In addition,the kinetic studies show that,the extraction of lead from zinc leaching slag is controlled by internal diffusion,and the apparent activation energy is 17.59 kJ/mol.