Recovery of ITO nanopowder from a waste ITO target by a simple co-precipitation method

Abstract

A simple co-precipitation method was used to recover ITO as a nanopowder from the waste ITO target residue in sputtering chambers. The waste ITO target was dissolved in HCl and then ammonia solution was added to make indium tin hydroxide (ITO precursor). After heat treatment up to 400 °C for 6 h, the colour of the ITO precursor changed from white to yellow. The prepared ITO nanopowder was homogeneous with a size of 10 nm and a polycrystalline structure. Over 95 wt% of ITO was recovered using this method. The In/Sn weight ratio was estimated to be 10 : 1, which is very close to commercial ITO. We tried to scale-up the preparation procedure by 20 times to reduce the amount of acid for a more environmentally friendly approach. The particle size was about three times larger than that obtained from the small scale and the In/Sn ratio was slightly different. However, they were still close to commercial ITO.