Sb2S3?ZnO?C体系热力学分析及应用

对Sb₂S₃-ZnO-C低温焙烧体系进行了热力学分析,首先分析了Sb-S-O和Sb-Zn-S-O系的优势区图,表明硫化锑直接转化为金属锑是可行的,且随着温度升高,Sb和ZnS的共存稳定区对氧分压和硫分压的要求降低;计算了在500～1 000 ℃下体系中各反应的标准吉布斯自由能变 (ΔG^θ),表明Sb₂S₃与ZnO交互反应极易首先进行,而后发生Sb₂O₃直接还原;对Sb₂O₃和ZnO的还原平衡CO含量计算表明,Sb₂O₃较ZnO易还原。高低品位两种硫化锑精矿的焙烧试验证实了热力学分析的准确性,锑生成率和固硫率分别达90%以上和89%左右,并有进一步提高的空间。

Thermodynamic Analysis of Sb2S3-ZnO-C System and Its Application

A thermodynamic analysis was conducted for the low-temperature roasting of Sb₂S₃-ZnO-C system. The analysis of predominance area of Sb-S-O and Sb-Zn-S-O systems in the diagram indicated that it was feasible for Sb2S3 to be directly converted into Sb. And the oxygen partial pressure and sulfer partial pressure for the coexistence of Sb and ZnS was decreased with the temperature rising. The calculation of the Gibbs free energy change (ΔG^θ) of the possible reactions in the system at the temperature of 500~1 000 ℃ showed that the interaction between Sb₂S₃ and ZnO was liable to be occurred firstly, followed by the reduction of Sb₂O₃ to Sb. The calculation of CO content for equilibrium of reduction of Sb₂O₃ and ZnO indicated that Sb₂O₃ was prone to reduction as compared to ZnO. The roasting tests with both high- and low-grade antimony sulfide concentrate verified the accuracy of thermodynamic analysis, showing the yielding rate and sulfur-fixing rate of antimony were over 90% and around 89%, respectively, which could still be further improved.