摘要
对锡铁精矿硫化焙烧过程中锡、铁反应热力学和铁还原动力学特征进行了分析，并对热力学分析结果进行了实验验证。结果表明：焙烧温度高于1273K，随温度升高Sn稳定区增大，SnS、SnO、SnO2稳定区缩小，Sn和SnO硫化趋势较Sn02大，提高锡硫化挥发效率应将锡物相定向还原生成金属Sn或SnO；反应温度高于958K时，对锡铁精矿进行硫化焙烧，锡的还原硫化历程为SnO2→Sn→SnS，铁的深度还原历程为Fe2O3→Fe3O4→FeO→Fe；焙烧温度1073-1473K和CO分压0．6～0．8范围内，可同步实现锡铁精矿中锡的有效硫化脱除和铁的深度还原，较好地佐证了热力学分析结果。Coats—Redfern法计算可知锡铁精矿铁还原反应表观活化能为7．44kJ／mol，其还原过程由内扩散、外传质或两者共同控制。
A study was implemented in order to analyze the reaction thermodynamics of tin and iron phases as well as the characteristics of iron reduction kinetics in the process of tin-bearing iron concentrates sulfidation roasting, and prove the thermodynamic results by experiments. The results shows that, the tin stable zones are gradually increased with roasting temperature being higher than 1273 K, while others＇ decreased, namely SnS, SnO and SnO2. The sulfidation trend of Sn and SnO are larger than SnO2, and the tin should be directly reduced to metallic Sn or SnO so as to improve the volatilization efficiency of tin phases. When roasting temperature is over 958 K, the tin dioxide reduction-sulfidation process is SnO2→Sn→SnS, and the iron oxide is Fe2O3→Fea O4→FeO→Fe. Tin can be effectively removed and iron can be deeply reduced in tin-bearing iron concentrates when roasting temperature is between 1073--1473 K and partial pressure of carbon monoxide is between 0. 6-0. 8, which corroborate thermdynamics analysis results well. Activation energy of iron phase reduction process which depends on internal diffusion, or external mass transfer or both appears to be 7.44 kJ/mol by Coats-Redfern.
基金
国家自然科学基金(51304092)
关键词
锡铁精矿
硫化焙烧
还原动力学
资源综合利用
tin-bearing concentrates, sulfidation roasting, reduction kinetics, comprehensive utilization of resources
