硫化铅精矿搭配硫尾矿渣富氧顶吹炼铅渣型理论分析

Theoretical analysis on slag type of lead sulfide concentrate and sulfur tailings slag in lead smelting by oxygen-enriched top blowing

基于富氧顶吹直接炼铅技术,提出硫化铅精矿搭配硫尾矿渣炼铅工艺,以实现硫尾矿渣的综合利用。熔炼过程渣型决定了炉渣的性质,进而影响熔炼过程能否顺利进行。根据熔炼过程渣相组成特点,以PbO-FeO-Fe_(2)O_(3)-SiO_(2)-CaO-ZnO渣系为研究对象,采用FactSage热力学软件计算并绘制该渣系相图。研究温度、w(Fe)/w(SiO_(2))、w(CaO)/w(SiO_(2))及ZnO质量分数等因素对炉渣熔化温度及液相生成区的影响。理论研究表明,w(CaO)/w(SiO_(2))的变化对炉渣熔化温度的影响与w(Fe)/w(SiO_(2))不同,且w(CaO)/w(SiO_(2))影响更为显著。炉渣中ZnO质量分数在6%~14%范围内增大时,炉渣的熔化温度变化较小;但当ZnO质量分数进一步增大时,炉渣的液相区逐步减小。在保证熔炼过程顺利进行的前提下,渣中ZnO的质量分数可控制在8%~10%范围内,有利于增大炉渣的液相区面积。验证试验表明,在熔炼温度为1 150℃、w(CaO)/w(SiO_(2))=0.3、w(Fe)/w(SiO_(2))=0.8条件下,采用富氧顶吹熔炼处理硫化铅精矿搭配硫尾矿渣可顺利进行,熔炼过程金属直收率为8%,渣中铅质量分数可达49.12%,烟尘率为13.18%。

Based on the oxygen-enriched top blowing direct lead smelting technology, a lead smelting process with lead sulfide concentrate and sulfur tailing slag was proposed to realize the comprehensive utilization of sulfur tailing slag. The slag type during the smelting process determines the property of the slag, which in turn affects the smooth progress of the smelting process. According to the slag phase composition characteristics of the smelting process, the phase diagram of PbO-FeO-Fe_(2)O_(3)-SiO_(2)-CaO-ZnO slag system were drawn and calculated using FactSage thermodynamics software. Effects of temperature, w(Fe)/w(SiO_(2)), w(CaO)/w(SiO_(2)) and ZnO mass fraction on the melting temperature and liquid phase generation zone of slag in oxygen-enriched top blowing smelting of lead sulfide concentrate and sulfur tailings slag were investigated. Theoretical research showed that the effect of the change of w(CaO)/w(SiO_(2)) on the melting temperature of slag was different from that of w(Fe)/w(SiO_(2)), and the effect of w(CaO)/w(SiO_(2)) was more significant. When ZnO mass fraction in the slag increased in the range of 6%-14%, the melting temperature of the slag changed little. However, as ZnO mass fraction increased, the liquid phase area of slag showed a decreasing trend. Under the premise of ensuring the smooth progress of the smelting process, ZnO mass fraction in the slag can be controlled within the range of 8%-10%, which was beneficial to increase the liquid zone area of slag. The verification experiment showed that under the conditions of 1 150 ℃, when the value of w(CaO)/w(SiO_(2)) was 0.3 and the value of w(Fe)/w(SiO_(2)) was 0.8, the treating of lead sulfide concentrate with sulfur tailings slag using oxygen-enriched top blowing smelting can be proceed smoothly, and the metal direct recovery rate during the smelting process was 8%, the lead mass fraction in the slag can reach 49.12%, and the fume rate was 13.18%.