再生铅低温碱性固硫熔炼的实验研究

针对我国传统再生铅生产工艺所存在的熔炼温度高、能耗大、铅和低浓度SO2烟气污染严重等弊端,在对NaOH-C-PbSO4-ZnO低温碱性炼铅体系进行理论分析的基础上,提出了一种再生铅的低温碱性固硫熔炼新工艺.以废铅酸蓄电池胶泥(以下简称胶泥)为实验原料,采用单因素实验法分别考察NaOH用量、熔炼温度、焦粉用量及固硫剂ZnO用量对金属铅直收率和ZnO固硫率的影响.获得优化实验条件如下：m(NaOH)/m(胶泥)=60%,熔炼温度为860℃,m(焦粉)/m(胶泥)=10%,m( ZnO)=m(理论量).在此优化条件下进行综合扩大实验,铅的直收率为99.09%,获得粗铅品位为98.86%,ZnO固硫率为93.37%. X射线衍射图谱分析可知,反应后原料中硫主要以ZnS的形式固定在渣中,NaOH绝大部分转变为Na2 CO3,生产过程中无SO2气体排放.

Extraction of lead from secondary lead through a low-temperature alkaline and sulfur-fixing smelting process

In view of serious shortcomings existing in a traditional secondary lead pyrometallurgical process such as high smelting temperature, large energy consumption and low concentration of SO2 fume together with lead vapor pollution, a low-temperature alka-line and sulfur-fixing smelting process of secondary lead was proposed in this work based on a thermodynamic analysis of the NaOHC-PbSO4-ZnO low-temperature alkaline system. The effects of NaOH amount, smelting temperature, coke amount and ZnO addition on the alkaline and sulfur-fixing smelting of spent lead-acid battery colloid sludge ( hereinafter referred to as colloid sludge) which was used as the test material were investigated by single factor experiments. The optimum conditions were determined as follows:m( NaOH)/m( colloid sludge) =60%, temperature 860℃, m( coke)/m( colloid sludge) =10%,and m( ZnO) =m( theoretic) . Un-der these above-mentioned optimum conditions, the average direct recovery ratio of lead was 99. 09%, the average grade of crude lead was 98. 86%, and the average sulfur-fixing rate for ZnO was 93. 37%. XRD spectra indicated that sulfur contained in the material was mainly fixed in the solid residue in the form of zinc sulfide, most of NaOH was converted into Na2 CO3 , and no SO2 emission existed in the smelting process.