Lead Flow Analysis Of Typical Lead Smelting Process

The rapid development of lead smelting industry in China, but also to discharge a large amount of heavy metals such as lead, resulting in serious metal pollution incidents. Lead metal pollution problems from lead smelting process were focused in this paper. The lead smelting production process was divided into batching system, bottom-blown furnace, reduction furnace, fuming furnace, smelting lead pot, electrolyzer, electric lead pot, based on analysis of the production technology and pollutant generation and discharge in present lead smelter process. The substance flow analytical method for a production and a production flow was constructed based on the method of substance flow analysis, and the main parameters and evaluation indexes were established, such as the direct lead obtain rate, lead recovery, the recycling rate of primary waste. The generation, emission, flow and circulation of each process were studied. The physical and chemical properties of lead element flow was analyzed, and the analytical methods for waster water, lead slag and dust were ascertained, based on the type of waste generated emissions in lead smelting system.A optimization model of the lead flow was set up on the production unit, lead dust recovery unit and the pollutant treatment unit for how to reduce the amount of natural resources and lead concentrates into final waste emissions problem, as followed:The results indicated that the measures of raising the direct lead obtain rate μ1of the production unit, lead recycling efficiency μ2of lead dust recovery unit, the recycling efficiency μ3of the pollutant treatment unit and the reusing rate μ4of the pollutant treatment unit would reduce the influence of lead smelting production on environment. The method and model mentioned were used to analyze the typical lead smelting process (liquid high-lead slag direct reduction process), and a lead element flow diagram of liquid high-lead slag direct reduction process was built and analyzed. The lead recoveries of lead bullion smelting and lead refining system were98.35%and99.51%, respectively, but the direct lead obtain rates were74.38%and50.28%which indicated there was a large space for improvement compared with the overseas advanced level. Lead dust generation per unit of bullion lead was0.31t/t; and the results of physical and chemical properties analysis showed that:tiny particles of lead dust were produced, PM2.5of lead bullion smelting and lead refining system accounted for22.7%-63.93%and1.93%-10.62%respectively, the active state of dust were very high, lead dust should be prepared to collect and dispose. The analysis results of optimization model indicated that, the lead recycling efficiency and the direct lead obtain rate should be improved, and the fugitive emissionsshould be prevent, then reduced sludge and desulfurization gypsum slag which with low lead content, and improved the reusing rate of the pollutant treatment unit. Lastly, suggestions were presented in this paper to problems occurring in the production process.