湿法炼锌铜砷渣加压浸铜及同步固砷

Pressure Leaching of Copper and Synchronous Solidificating Arsenic from Copper-arsenic Precipitation in Zinc Hydrometallurgy

针对湿法炼锌冶炼过程中产出的铜砷渣进行综合回收利用,在研究铜砷渣矿物组成及热分解特性的基础上,开展了加压浸出铜及同步固砷工艺研究,考察了铜、砷元素的行为。结果表明:在反应温度135℃、反应时间4 h、液固比25∶1、硫酸初始浓度50 g/L、氧分压500 kPa、铁砷摩尔比值为1的条件下,浸出渣中铜含量仅为2.03%,铜浸出率达到97.72%,砷含量达到26.06%,砷浸出率仅为4.02%,浸出液中铜浓度达到20.47 g/L,砷浓度小于0.63 g/L,铜砷分离效果好;在反应过程中,Cu 3 As优先发生氧化溶解,铜的浸出需要一定时间,铜的浸出与砷的沉淀同时进行;浸出液pH值与浸出液中As浓度变化趋势基本一致;在反应前期,砷与铁生成臭葱石产生的酸可以补充铜浸出消耗的酸。

In view of the comprehensive recovery and utilization of copper-arsenic precipitation produced in the process of zinc hydrometallurgy,based on the study of mineral composition and thermal decomposition characteristics of copper-arsenic precipitation,pressure leaching of copper and synchronous arsenic fixation were studied,and the leaching behavior of copper and arsenic elements was investigated.The results show that,reaction temperature of 135℃,reaction time of 4 h,liquid-solid ratio of 25,initial sulfuric acid concentration of 50 g/L,oxygen partial pressure of 500 kPa and iron-arsenic molar ratio of 1,the copper content in the leaching residue is only 2.03%,the copper leaching rate is 97.72%,and the arsenic content is 26.06%,the arsenic leaching rate is only 4.02%.The concentration of Cu reaches 20.47 g/L and the concentration of As is less than 0.63 g/L.The separation effect of copper and arsenic is ideal.During the reaction process,Cu 3As undergoes oxidative dissolution firstly,and the leaching of copper requires a certain amount of time.The leaching of copper is carried out simultaneously with the precipitation of arsenic.The variation trend of the pH value of the leaching solution and the concentration of As in the leaching solution is basically consistent.In the early stage of the reaction,the acid generated by the formation of scorodite from arsenic and iron can supplement the acid consumed by copper leaching.