粗铅冶炼过程中砷镉铊的走向分布及治理措施

Distribution and treatment measures of arsenic,cadmium and thallium in the process of crude lead smelting

在粗铅冶炼工艺中,铅精矿和其他含铅物料中的砷、镉、铊分布于各工序环节,不利于有价金属资源的回收,而且加大了冶炼废弃物的处理难度,另外还对人体健康和环境造成负面影响。现有文献对于砷、镉、铊在粗铅冶炼过程中的分布及趋向还未见报道,本文根据某冶炼企业实际生产情况,统计了2021年及2022年分别为期14d的两套物料平衡数据,对砷、镉、铊在各冶炼工序的分布进行了分析,得到以下结论。砷的分布情况:在底吹炉工序中,约85%砷进入高铅渣,约9%砷进入烟灰,约6%砷进入硫酸净化污酸系统;在还原炉工序,约70%以上砷形成铅铜锍进入粗铅,约20%砷进入还原炉烟灰,10%以下的砷通过还原渣进入烟化炉。镉、铊的分布情况:高度富集于底吹炉和侧吹炉烟灰中,其中底吹炉烟灰中富集比例为85%~95%,只有5%~15%进入高铅渣转至还原炉工序,极少部分进入硫酸系统。企业采用开路底吹炉烟尘方式减少粗铅冶炼系统中砷、镉、铊的含量,开路标准是烟尘含镉超过20%时从收尘系统开路,当烟尘含镉低于15%停止开路,取出的烟尘可直接作为回收镉的原料外售。本文分析结果及解决方法可为同类企业控制冶炼系统中砷镉铊的分布提供参考。

In the process of crude lead smelting,arsenic,cadmium and thallium in lead concentrate and other leadcontaining materials are distributed in each process,which is not conducive to the recovery of valuable metal resources,but also increases the difficulty of smelting waste treatment,and has a negative impact on human health and the environment.The distribution and trend of arsenic,cadmium and thallium in the smelting process of crude lead have not been reported in the existing literature.Based on the actual production situation of a smelting enterprise,this paper statistics two sets of material balance data for 14 days in 2021 and 2022 respectively,and analyzes the distribution of arsenic,cadmium and thallium in each smelting process.The distribution of arsenic is as follows.In the bottom blowing process,about 85%arsenic enters into high lead slag,about 9%arsenic enters into dust,and about 6%arsenic enters into sulfuric acid purification system;In the process of the reduction furnace,about 70%of the arsenic forms lead copper matte into the crude lead,about 20%of the arsenic enters the reduction furnace dust,and less than 10%enters the fuming furnace through the reduction slag.The cadmium and thallium is highly enriched in the bottom blown furnace and side blown furnace soot,of which the enrichment ratio of the bottom blown furnace dust is 85%to 95%,only 5%to 15%enter the process of transferring the high lead slag to the reduction furnace,and very little enters the sulfuric acid system.Enterprises adopt transferring bottom blown furnace dust to reduce the content of arsenic,cadmium and thallium in the crude lead smelting system.The transfer standard is when the dust contains more than 20%cadmium,and stop transfer when the dust contains less than 15%cadmium.The dust taken out can be directly sold as raw materials for cadmium recovery.The analysis results and the solution in this paper can provide reference for similar enterprises to control the distribution of arsenic,cadmium and thallium in smelting system.