METHOD OF SELECTIVE RECOVERY OF VALUABLE METALS FROM MIXED METAL OXIDES

摘要

The present invention relates to a process for recovering metals from indium tin oxide (ITO) scrap. It allows the selective recovery of indium and tin from waste ITO by means of a simple and environmentally benign dissolution-deposition method, with no requirement of using strong corrosive acid/alkaline chemicals (e.g. hydrochloric acid, nitric acid, sulfuric acid and sodium hydroxide) for dissolution and complicated procedures/operation. The dissolution baths can be reused without observable recovery deterioration. It significantly reduces the cost requirement in the recovery process.

主权项

1. A method for sequentially recovering indium and tin from ITO-containing waste comprising:
a) reducing the size of ITO-containing materials by shredding and crushing so as to form finely-divided particles; b) subjecting the finely-divided particles to chemical and physical cleaning for pre-treatment to substantially avoid the interference in dissolution step; c) transferring the pre-treated particles to a first dissolution bath comprising a first bath formulation at a bath temperature ranging from 60° C. to 120° C. with continuous stirring for 30-180 minutes to dissolve the pre-treated particles; d) adding 50-300% by volume of water into the solution containing the dissolved particles from step (c) to form a first mixture and filtering the first mixture so as to collect an indium-rich filtrate and a tin-rich filtrand; e) putting an indium plate in the indium-rich filtrate for 1-10 hours to remove the tin residue by a displacement reaction; f) recovering indium with purity not less than 99.9% from the indium-rich filtrate by a first deposition process; g) reusing the dissolution bath in step (c) for the next recovery cycle after water evaporation.