CaO-SiO_2-FeO体系中选择性分离锌铅的实验研究

Study on Selective Separation of Zn and Pb from CaO-SiO2-FeO Slag System

为了探讨CaO-SiO2-FeO体系中选择性分离回收Zn,Pb的可行性,在系统分析该体系中Zn,Pb挥发行为的基础上,研究了温度、基体成分及Cl含量等因素如对Zn,Pb挥发率的影响.结果表明,低温、低碱度、低FeO含量、低Cl含量条件下,Zn与Pb的挥发率差异达到最大,原因在于该种条件下Zn倾向于以ZnFe2O4等复杂化合物形式滞留在渣基体中,而Pb以氯化物形式挥发;在此基础上,对实验后的渣基体进行升温、并添加一定量的C粉等还原剂后,渣中Zn会以单质形式挥发分离,从而实现粉尘及飞灰熔融处理过程中Zn、Pb的选择性分离回收.

In order to reveal the feasibility of selective separation of zinc and lead from CaO-SiO2-FeO slag system,based on the research about the vaporization behaviors of zinc and lead,the difference between the vaporization rates of zinc and lead from the slag system under different conditions such as temperature,slag composition,and Cl content was studied.The results showed that in the conditions of lower temperature,lower Cl content,and keeping the basicity and FeO content of slag at lower level,the difference between the removal rates of zinc and lead reached the maximum value.The reason behind this is that under this condition,Zn tends to be combined with slag matrix to form complicated compounds such as ZnFe2O4,while Pb has a less affinity with matrix and is apt to volatile in the form of chlorides.Furthermore,at higher temperature with the addition of carbon powder,most of zinc can be removed from the residue in the form of metallic zinc vapor.This research can provide theoretical guidance for selective recovery of zinc and lead resources from the dust and fly ash during smelting process.