含铅废渣料还原造锍熔炼回收铅和银工艺

Recovery of lead and silver from lead-bearing wastes using reducing-matting smelting process

针对铅锌冶炼企业产出大量含铅固体废弃物难以环保经济回收的难题,提出从多种含铅废料中回收二次铅的还原造锍熔炼新工艺.在热力学计算的基础上,进行以铅膏、铅渣、铅烟灰和黄铁矿烧渣的设计混合料为熔炼对象,以氧化铁为固硫剂,焦粉为还原剂,苏打和芒硝作为添加剂的工艺实验,研究熔炼过程中各影响因素对铅和银直收率的影响.得到优化的工艺条件:Fe O/Si O2质量比为1.10,Ca O/Si O2质量比为0.30,添加剂组成中Na2CO3/Na2SO4质量比为7∶3,焦粉用量为含铅物料质量的15%,熔炼时间为2 h,熔炼温度为1200℃.在此条件下综合实验中铅直收率为85.95%,银直收率为83.15%.新工艺具有固硫、综合利用和一步炼铅的优点.

In view of the difficulty in environmental and economic treatments of lead-bearing wastes generated in lead and zinc smelter,a new reducing-matting smelting process was proposed to recycle secondary lead from multiple lead-bearing wastes in this paper. In the process,the designed mixture of lead sludge,lead slag,lead ashes and pyrite cinder was used as a smelting object,and ferric oxide,soda and mirabilite and coal powders were a sulfur-fixing agent,additive and reductant,respectively. The effects of factors on the direct recovery rates of lead and silver during the smelting process were studied in detail based on thermodynamic calculations. The optimum conditions are obtained as the following： the mass ratio of FeO to SiO2 is 1. 10,the mass ratio of CaO to SiO2 is 0. 30,the mass ratio of Na2CO3 to Na2SO4is 0. 7∶ 0. 3,the dosage of coal powders is 15% of lead-bearing wastes,the smelting temperature is 1200 ℃,and the smelting time is 2 h. Comprehensive experiments show that under the optimum conditions,the direct recovery rates of lead and silver are 85. 95% and 83. 15%,respectively. The process has significant advantages of sulfur fixation,comprehensive utilization and one-step lead smelting.