电子废弃物回收镓技术的研究进展

Techniques of recycling gallium from e-waste

含镓电子废弃物通常可分为废弃电子产品及其生产过程中产生的含镓废料两类,由于伴生重金属、易燃有机物等有害物质而具有环境和资源的双重属性,其资源循环近年来受到广泛关注。镓在电子废弃物中主要以化合物形式赋存,具有伴生元素多、物理化学性质稳定等特征。本工作系统梳理了含镓电子废弃物回收处理现状,总结了湿法冶金、火法冶金及生物冶金等技术在回收不同种类的含镓电子废弃物的应用,并通过对比不同物理化学属性的含镓物料使用回收技术以及分离、净化方式的不同,指出了目前现存的回收含镓电子废料的技术问题及未来的发展方向。要点:(1)目前含镓电子废弃物激增,废弃物的回收具有资源与环境双重价值。(2)湿法冶金是目前回收电子废弃物中的镓的主流方式,火法冶金、生物冶金等传统镓回收技术也可用于电子废弃物的回收。(3)不同的电子废弃物的镓回收需要不同的技术手段,一般采用火法或湿法从GaN废料回收镓;Ga As废料提镓多采用湿法获得;从IGZO(GZO)显示屏中提镓多采用酸浸后再纯化获得。(4)GaAs,GaN废料是镓回收的主要来源,IGZO(GZO)显示屏和CIGS废料所占比例较低。

As an important rare element,gallium has a wide range of applications in many fields such as industry,medicine,military,etc.However,due to the low concentration of gallium in the earth’s crust and its wide distribution,it exists in the form of chalcopyrite.It is generally recovered from the by-products of gallium-containing waste in traditional industries such as sphalerite,aluminum ore,fly ash,etc.Gallium-containing electronic waste can be divided into two types of waste electronic products and gallium-containing waste generated in the production process.To solve the problem of shortage of gallium resources,researchers currently recover gallium from gallium-containing electronic waste.Due to the associated heavy metals,flammable organic substances,and other harmful substances,it has the dual attributes of environment and resources extensive attention.Gallium mainly exists in the form of compounds in e-waste such as Ga N,Ga As,CIGS,IGZO,and has the characteristics of many associated elements and stable physical and chemical properties.Generally,the fire or wet method is used to recover gallium from Ga N waste;gallium of Ga As waste is mostly obtained by wet method;gallium is extracted from IGZO(GZO)display screen by acid leaching and then purified.This article systematically sorts out the current status of gallium-containing electronic waste recycling and treatment,summarizes the applications of hydrometallurgy,pyrometallurgy,and biometallurgy in recycling different types of gallium-containing electronic waste.The difference in the use of material recovery technology and the separation and purification methods points out the current technical problems and the future development direction of recycling gallium-containing electronic waste.Key learning points:(1)Gallium-containing electronic waste is proliferating,and the recycling of waste has both resource and environmental values.(2)Hydrometallurgy is currently the mainstream method for recovering gallium from electronic waste.Traditional methods such as pyrometallurgy and biometallurgy can also be used for the recovery of gallium from electronic waste.(3)Different types of electronic wastes require different methods to recover gallium.Generally,fire or wet methods are used to recover gallium from Ga N waste;the gallium in Ga As waste is usually obtained by wet method;the gallium extracted from the IGZO(GZO)display is mostly obtained by acid leaching and then purification.(4)Ga As and Ga N wastes are the main sources of gallium recycling,and the proportion of gallium recycling of IGZO(GZO)display and CIGS scrap is relatively low.