对Bi2S3-ZnO-Na2CO3低温熔盐体系进行热力学分析,计算了在700~1 500 K温度下体系中各反应的标准吉布斯自由能变化值(ΔG TΘ),并绘制了相应的ΔG TΘ—T图。热力学分析结果表明,在700~1 100 K温度范围内,Bi2S3中的Bi会被C还原成金属Bi进入金属相中,S将以ZnS形式进入固体物渣中。根据分析结果,在700~1 100 K温度下,以Na2CO3等钠盐为熔剂、ZnO为固硫剂、粉煤为还原剂,开展了验证试验。试验得到了直收率达98%的粗铋,S几乎100%以ZnS的形式固定在渣中,与热力学分析结果一致。
The thermodynamic analysis of Bi2S3-ZnO-Na2CO3 low temperature molten salt system was carried out.Based on calculating reactions entropy() of this low temperature molten salt system at 700-1 500 K,the relationship between and reaction temperature(T) within this temperature range was obtained.The results of thermodynamic analysis show that bismuth in Bi2S3 can be reduced by carbon to metal Bi and then get into the metal phase,and sulfur can be fixed in ZnS and get in solid slag.By using soda and other sodium salt as flux,zinc oxide as sulfur additives,coal or coke powder as reducing agent,two verification experiments were carried out at 700-1 100 K.The verification test results show that crude bismuth can be obtained at this low temperature.Bismuth direct yield is greater than 98%,and all sulfur embraced in raw materials can be fixed as zinc sulfide.The verification test results are in accordance with the thermodynamic analysis results.