Na_2CO_3-NaCl-C-PbSO_4-CuO体系热力学分析及应用研究

Thermodynamic Analysis and Application of Na_2CO_3-NaCl-C-PbSO_4-CuO System

对Na2CO3-NaCl-C-PbSO4-CuO低温熔盐炼铅体系进行热力学分析,绘制了600～1 200 K时体系中主要反应的△GθT-T图.结果表明,在600～1 200 K范围内,PbSO4可以被还原成金属Pb,硫能够固定在CuS中,钠盐可转变成Na2CO3形态存在,且在1 123 K时,体系中的稳定物相以金属Pb、CuS和Na2CO3为主.提出了Na2CO3-NaCl-C-PbSO4-CuO低温熔盐炼铅新工艺.在1 153 K下,以废铅酸蓄电池胶泥为原料、Na2CO3-NaCl为熔剂、CuO为固硫剂、焦粉为还原剂,进行了验证试验.产出的粗铅品位98.10％,铅直收率93.27％,铅的总回收率99.25％,93.81％的硫以CuS形式被固定在渣中,过程无SO2气体产生,与热力学分析结果相符合.

Thermodynamic analysis of Na2 CO3-NaCl-C-PbSO4-CuO low temperature alkaline system for lead smelting was carried out. Curves between △GθT and reaction temperature （T） of different reactions at 600- 1200 K were obtained based on calculation. The results show that PbSO4 can be reduced to metal lead, sulfur can be fixed in CuS, and sodium salt can be converted into Na2CO3 at 600-1200 K. The stable phases of the system are mainly composed of metal lead, CuS and Na2CO3 at 1123 K. New process to smelt Iead in Na2 CO3-NaCl-C-PbSO4-CuO low temperature molten salt was proposed. Verification test was carried out at 1 123 K applying spent lead-acid battery colloid sludge as material, Na2 CO3-NaCl as flux, CuO as sulfur additives, and coke powder as reducing agent. Grade of crude lead is 98.10% with lead direct yield of 93.27% and lead total yield of 99.25%. 93.81% of sulfur embraced in raw materials can be fixed as CuS without SO2 emission through whole process. The verification test results are in accordance with thermodynamic analysis results.