The separation and recovery of indium, gallium, and zinc from spent GZO(IGZO) targets

- A recovery technology of In, Ga and Zn from spent GZO(IGZO) targets was studied.
- This process includes leaching, extraction, stripping, precipitation, calcination.
- The obtained products are reusable metal oxides with high purity.
- In, Ga and Zn recovery is essential for waste reduction and resources circulation.

As the waste of ZnO base display panel increased in recent years, it is a big issue to treat the spent gallium zinc oxides (GZO) and indium gallium zinc oxides (IGZO) targets. A recovery process of indium, gallium, and zinc has been studied. The process was arranged to leach the targets by nitric acid and extract the rare metal individually. To optimized the separation of indium and gallium, the pH value, concentration of extractant and stripping agents, organic-aqueous ratio and reaction time were investigated. In the first step, indium was extracted by Di-(2-ethylhexyl) phosphoric acid (D2EHPA) to the organic phase. By controlling the conditions, gallium and zinc remained in the aqueous. After indium extraction, gallium was extracted by same extraction agent in different conditions with almost no zinc extracted. Indium and gallium were then stripped by hydrochloric acid separately. With the optimal conditions, the recovery of both indium and gallium could be up to 99.9%. After separation, these three metals were recycled and reused by precipitation and calcination as metal oxides with the purity over 99.5% and then back to the manufacture processes eventually.