铜阳极泥湿法预处理除杂同步富集稀贵金属

Removing impurities and enrichment of rare and precious metals of copper anode slime by hydrometallurical pretreatment

铜阳极泥高效预处理除杂是分离精炼稀贵金属的前置关键环节。本文基于铜阳极泥的理化特征,提出H_(2)SO_(4)-H_(2)O_(2)体系常压选择性自催化氧化除杂同步高效富集稀贵金属新工艺,考察了多种因素对Cu、As、Se、Te浸出率的影响。结果表明:铜阳极泥主要物相为PbSO_(4)、CuSO_(4)、Ag_(2)Se、Cu_(2)Te、Cu_(2)Se和Cu等,在H_(2)SO_(4)用量120 mL/kg、H_(2)O_(2)用量260 mL/kg、液固质量比5∶1、反应温度35℃和反应时间1 h的优化条件下,Cu、As的浸出率分别为98.33%、58.22%,Se、Te的浸出率分别仅为7.49%和23.97%,而Au和Ag均未浸出。浸出渣微观组织为尺寸50~100 nm的镶嵌式团状颗粒,主要由PbSO_(4)、Se、Ag_(2)Te和Ag物相组成,原料中Cu_(2)Te、Cu_(2)Se和Ag_(2)Se物相明显消失。浸出渣中Ag和Au的含量分别为9.33%和0.293%,富集比为1.5,Cu含量由14.30%降至0.39%,满足后续贵金属分离精炼要求。该工艺在常温常压下实现了铜阳极泥中杂质的高效分离和稀贵金属的定向富集。

Efficient pretreatment for removing impurities of copper anode slime is a crucial pre-requisite step in the separating and refining of rare and precious metals.In this paper,based on the physical and chemical characteristics of copper anode slime,a novel process of selective autocatalytic oxidation impurity removal and efficient enrichment of rare and precious metals in H_(2)SO_(4)-H_(2)O_(2) system was proposed.The effects of various factors on the leaching rates of Cu,As,Se and Te were investigated.The results show that the main phases of copper anode slime are PbSO_(4),CuSO_(4),Ag_(2)Se,Cu_(2)Te,Cu_(2)Se and Cu.Under the optimum conditions of H_(2)SO_(4) dosage of 120 mL/kg,H_(2)O_(2) dosage of 260 mL/kg,liquid-solid mass ratio of 5∶1 reaction temperature of 35℃and reaction time of 1 h,the leaching rates of Cu and As are 98.33%and 58.22%,respectively;the leaching rates of Se and Te are only 7.49%and 23.97%,respectively,while Au and Ag are not leached.The microstructure of the leaching residue is shown as mosaic agglomerate particles with 50-100 nm in size,mainly composed of PbSO_(4),Se,Ag_(2)Te and Ag phases.The phases of Cu_(2)Te,Cu_(2)Se and Ag_(2)Se in the raw materials disappear obviously.The contents of enriched Ag and Au in leaching residue are 9.33%and 0.293%,respectively.The enrichment ratio is 1.5,and Cu content decreases from 14.30%to 0.39%,which achieves the requirements of subsequent precious metal separation and refining.The process achieves efficient separation of impurities and targeted enrichment of rare and precious metals at room temperature and atmospheric pressure of copper anode slime.