辉锑矿铁源固硫还原熔炼直接炼锑

Reducing and sulfur-fixing smelting of stibnite to produce antimony by one-step using iron materials as sulfur-fixing agent

以Na_2CO_3-NaCl熔盐作为熔炼介质,提出以铁源为固硫剂的辉锑矿还原固硫直接熔炼,以解决当前炼锑工艺存在的温度高、流程长等缺点。结果表明:在Sb_2S_3-FeO-C反应体系中,Sb_2S_3的还原固硫反应分步进行,Sb_2S_3先与FeO发生交互反应生成Sb_2O_3和Fe S,Sb_2O_3再被还原剂还原成金属锑。以Fe_2O_3为固硫剂的熔炼实验得到最佳工艺条件为:α_(Fe_2O_3)=1.0、碳粉质量为精矿质量的40%、熔炼温度850℃、熔炼时间60 min。在此最佳条件下,锑直收率为91.48%,粗锑品位94.31%。较传统火法炼锑工艺,熔炼温度降低300℃以上,熔炼过程中硫以FeS形式被固定,消除低浓度二氧化硫烟气的污染。

In the views of the shortcomings in the current antimony smelting process which are high energy consumption and a long flow, a new process was proposed to smelt antimony directly from stibnite by reducing and sulfur-fixing reaction in NaCl-Na_2CO_3 molten salt. The reaction mechanism of reductive sulfur-fixation process of Sb_2S_3 was investigated. The results show that, for Sb_2S_3-FeO-C system, Sb_2O_3 and Fe S are generated by sulfur-fixation reaction between Sb_2S_3 and FeO. And then, Sb_2O_3 can be consecutively reduced to Sb by reductive agent. The influencing parameters during smelting process are comprehensively investigated, including sodium salt content and composition, ferric oxide dosage, smelting temperature and smelting time. The optimum conditions are determined as follows:α_(Fe_2O_3)=1.0, mC:mconcentrate=40%, smelting temperature of 850 ℃ and smelting time of 60 min. Under the optimal smelting conditions, the average direct recovery rate of antimony and grade of crude antimony are 91.48% and 94.31%,respectively. Comparing to the traditional pyro-metallurgical process, the smelting temperature of present process is reduced at least 300 ℃. And sulfur is fixed in the form of FeS in the smelting process, so low concentration of SO_2 emission could be avoided completely.