硫代硫酸盐回收废弃印刷线路板中金的研究新进展

Research status of recycling of gold from waste printed circuit boards with thiosulfate

查明WPCBs中金赋存特点、硫代硫酸盐浸金的原理和WPCBs中金的硫代硫酸盐浸出及其回收研究现状,能更好地为硫代硫酸盐回收WPCBs中金的应用发展指明方向。研究表明,WPCBs中金主要有以电触点材料、导电材料、金基焊料和电子浆料等金属形态存在;硫代硫酸盐浸金体系以O2为氧化剂、S2O3^2-为配位基、Cu^2+和NH4^+作为催化剂,Cu(NH3)4^2+既是氧传输载体,也是金氧化还原的关键,S2O3^2-为亚稳态的物质,易与溶液中其他离子反应,导致溶液成份复杂;为减小其他金属对后续金浸出的影响,应先脱除WPCBs中铜、铁和铝等;硫代硫酸盐浸金体系主要有“Na2S2O3+Cu^2+”、“(NH4)2S2O3+Cu^2+”和“S2O3^2-+NaCl”等三类。从硫代硫酸盐浸金液中回收金的方法有置换沉淀法、树脂吸附法、活性炭吸附法、微生物吸附法、溶剂萃取法、液膜分离法和电积冶金法等。

This paper summarized the occurrence characteristics of gold in WPCBs,mechanism of gold leaching with thiosulfate,gold leaching technology of Au in WPCBs with thiosulfate,and recovering gold from thiosulfate solution,which could be conducive to the development and improvement of thiosulfate recycling of gold from WPCBs.In WPCBs,gold was used mainly as electric contact materials,conductive materials,gold base solders and electronic paste,etc.In thiosulfate leaching system,oxygen is an oxidant,S2O23^-is the ligand,Cu^2+and NH 4+are catalyst,Cu(NH3)4^2+served as both oxygen carrier and the key to gold redox.The S2O3^2-is the metastable material,and is easy to react with other ions in solution,resulting in complex solution composition.In order to reduce the influence of other metals on subsequent gold leaching,the copper,iron and aluminum in WPCBs should be removed first.There are three main types of the thiosulfate leaching system:“Na2S2O3+Cu^2+”,“(NH4)2S2O3+Cu^2+”and“S2O3^2-+NaCl”.Gold in thiosulfate leaching solution is recovered by the replacement sedimentation,resin adsorption,active carbon adsorption,biosorption,solvent extraction method,membrane separation,and electrowinning,etc.