铅锌混合硫化精矿的低温熔盐还原固硫熔炼

Reductive sulfur-fixation smelting of lead and zinc sulfide mixed concentrate in soda molten salt at low temperature

针对铅锌混合硫化精矿烧结-密闭鼓风炉还原熔炼工艺(ISP)熔炼温度高、能耗大和大气污染严重等弊端,提出一种低温熔盐炼铅分离铅锌的新工艺。采用单因素实验法研究固硫剂ZnO和碳酸钠的用量、熔炼温度及熔炼时间等工艺参数对铅的直收率及ZnO固硫率的影响。结果表明:确定最佳条件为ZnO扩大实验的结果良好和精矿的质量比为0.36:1,碳酸钠和精矿的质量比为3.2:1,熔炼温度为880℃和熔炼时间为60 min。在此优化条件下扩大实验的结果良好:铅直收率为97.15%,粗铅品位为98.52%,ZnO固硫率为95.42%,水浸渣含Zn 55.80%(质量分数)。XRD物相分析表明:硫主要被固定在ZnS中,Na_2CO_3熔盐的物相未发生改变,可循环使用。

In view of serious shortcomings,such as high smelting temperature,large energy consumption and atmospheric contamination,existed in the imperial smelting process（ISP）,a low-temperature molten salt smelting process to directly produce lead from the lead and zinc mixed sulfide concentrates was proposed.The influencing factors,including the smelting temperature,reaction time and dosage of ZnO and salt,were investigated in detail using single-factor experiments.The results show that the optimum conditions are determined as follows：mass ratio of ZnO and concentrate is 0.36：1,mass ratio of Na2CO3 and concentrate is 3.2：1;smelting temperature is 880℃ and smelting time is 60 min.Under above-mentioned optimum conditions,some encouraging results are obtained as follows：the direct recovery rate of lead reaches 97.15%,the grade of crude lead reaches 98.52%,the sulfur-fixing rate for ZnO reaches 95.42%,the mass fraction of zinc in the leaching slag is 55.80%（mass fraction）.The XRD results indicate that sulfur is mainly fixed in the form of ZnS,whereas,the Na2CO3 molten salt does not react with other components,serving only as a reaction medium.