Blast Furnace Lead Smelting Slag Fuming Volatile Zinc

Sintering roasting-blast furnace smelting process is still the main smelting method for producing lead at present.Lead slag has an extremely high recovery value because it contains valuable metals such as Zn,Pb and so on.Therefore,the recovery and utilization of lead slag can save precious resources,increase the comprehensive utilization ratio of raw material,raise economic benefit and reduce environmental pollution.The development situation of lead smelting was introduced,and the treatments of lead slag were emphatically reviewed.The fuming and volatilization of lead slag and the recovery process of valuable metals such as Ni,Co,Cu and Ag and so on are theoretically analyzed.The fuming process of fuming furnace is that pulverized coal and air are injected to the slag bath.The heat generated reduce ZnO and PbO to fume Zn and Pb as a vapour from the furnace bath and is immediately reoxidized above the bath to form ZnO and PbO fume.Compared with other processes,it has the following advantages:high metal recovery ratio,large throughput and low quality coal is useableness with heating agent and reductant. On the other side,this craftwork is prone to achieve mechanization and automatization,and waste heat make use effectually.It is widely used to treat lead slag,low grade zinc oxide ore,zinc leaching residue,electric arc furnace dust,tin-rich slag and middlings contained rich tin and so on.The physical properties of lead slag were researched by using modern analysis and testing technologies such as XRD and TG-DSC and so on.Then the optimum fuming process parameters are obtained by studying the influence of fuming temperature,fuming time,coal dosage,lime dosage and blast volume on volatilization ratio of zinc and lead in lead slag.This project is lead slag and 35%coal marshal 6%CaO,as fuming temperature 1473K,fuming time 70min,blast volume 10L·h^-1.Under the optimum conditions,the contents of Zn and Pb in the slag are reduced to 1.52%,0.19%from 14.82%,3.01% respectively,and volatilization ratio of zinc and lead can reach 90.32%,94.04% respectively.In order to reclaim valuable metals such as Ni,Co,Cu and Ag in the fuming residue, gypsum acts as sulphidizing agent and the exploratory experiments on matte smelting show that this method can get better conditions.The project is fuming residue and 4%gypsum,as smelting temperature 1523K,constant temperature time 20min.Under these conditions,the contents of Ni,Co,Cu and Ag in the matte are 2.47%,6.09%,7.76%,263g/t respectively, and recovery ratio of Ni,Co,Cu and Ag are 83.30%,98.08%,56.32%,81.95% respectively.The industrial flowsheet of the comprehensive treatment of lead slag is designed by experimental study.This article tries to provide theoretical basis for utilizing the slag.