难处理锡铅共生精矿绿色高效冶炼工艺

Green and high-efficiency smelting process for refractory lead-tin symbiotic concentrate

  • 摘要: 针对难处理锡铅共生精矿,开发了一种“固砷-还原固硫低温熔炼”的冶炼工艺,对比传统富氧顶吹、底吹锡铅还原工艺,新工艺锡直收率提升60%~70%,铅直收率提升70%~90%,锡、铅直收率均接近98.5%;还原反应温度降低300~600 ℃,两段式升温可有效避免铅、砷等重金属粉尘及低浓度SO2的排放,一步炼制法可大幅提高锡铅回收率,降低成本。其中固砷反应的较优工艺参数为:反应温度200~300 ℃,反应时间 > 20 min,固砷剂的用量是锡铅精矿中As氧化物反应理论质量的2倍以上,锡铅合金中的含砷量稳定在0.000 3%左右,排出烟气中As含量稳定在0.003‱。还原剂低温熔炼的较优工艺参数为:反应温度750~1 200 ℃,反应时间 > 80 min,还原剂用量与投入锡铅精矿质量的比例 > 5%,固硫剂的用量是锡铅精矿中金属硫化物反应理论质量的0.5倍及以上,锡铅合金中的Sn直收率稳定在97.2%~98.1%,Pb直收率稳定在95.4%~98.2%,锡铅合金中的硫元素占比稳定在0.001%左右。

     

    Abstract: In this paper, a smelting process of "low temperature smelting of arsenic-reduction and sulfur-fixing" was developed for handling refractory tin-lead symbiotic concentrate. Compared with traditional oxygen-enriched top-blowing and bottom-blowing tin-lead reduction process, the new process boasts prominent advantages: the direct recovery of tin and lead are close to 98.5%, with an increment of 60%~70% and 70%~90%, respectively; the reduction reaction temperature is reduced by 300~600 ℃, the two-stage heating can effectively avoid the emission of lead, arsenic and other heavy metal dust and the low-concentration SO2, and the one-step refining method can greatly improve the recovery rate of tin-lead and reduce costs. The best process parameters for arsenic solidification reaction are: reaction temperature, 200~300 ℃; reaction time, over 20 min; the dosage of arsenic solidification agent, more than twice the theoretical mass of As oxide in tin-lead concentrate; the arsenic content in lead-tin alloy and flue gas, stably at 0.0003% and 0.003‱, respectively. The best process parameters of low-temperature smelting of reducing agent are: reaction temperature, 750~1 200 ℃; reaction time > 80min; ratio of the dosage of reducing agent to the mass of tin-lead concentrate > 5%; the dosage of sulfur-fixing agent, 0.5 times or more of theoretical mass of metal sulfide in tin-lead concentrate; the direct recovery of Sn and Pb in tin-lead alloy, stably at 97.2% ~ 98.1% and 95.4%~98.2%; sulfur element in tin-lead alloy, stably at about 0.001%.

     

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