Indium Prepared From Indium-Tin-Oxide (ITO) Target

ITO target, which is used in preparing ITO films by Magnetron Sputtering, is an electrode in manufacture conductive glasses. However, due to cuttings and waste products generated during the production of target materials, the utilization ratio of target sputtered coated films is just up to 30 %, and the rest of them becomes waste target. Therefore, Indium prepared from Waste Indium-Tin-Oxide (ITO) target are the main resources of reproduced Indium and recovery processing of waste target materials is in high theoretic and practical value. Owing to the semi-conductor mainly produced from high-purity Indium, as well as the basis materials of microelectronic device composed of high-purity Indium, Gallium, Phoshporus, Arsenic, the requirement of the purity of Indium is enhanced quickly with the development of semi-conductor industry.In the present study, the key factors in the hydrochloric acid dissolving-aluminum substitution-smelting-electrolysis process for the high-purity indium preparation from waste ITO target are investigated. The experimental results indicate that waste ITO target is well dissolved in hydrochloric acid (6mol/L) with the dosage of 4 times stoichiometry at 90℃. The separation of indium from tin is complete at pH 3.0-3.5, and optimal temperature for indium smelting is 350℃. The indium with purity above 99.9974% can be prepared under the optimal electrolysis condition, and the quality of the ingot indium is consonant with the international standard of YS/T 257-1998. The overall recovery of indium is 91%. The experiment has been done with advantages of low powder consumption, simple circuit, high recovery rate of Indium.