Application of sub-critical water for recovery of tin and glass substrates from LCD panel E-waste

Abstract

Tin and transparent glass substrate were efficiently recovered from color filter (CF) and thin-film transistor (TFT) glasses in LCD panel wastes using sub-critical water (sub-CW) at various treatment temperatures and reaction time. Treatment for 5 min using sub-CW added with NaOH resulted in a 95% recovery of tin from CF and TFT glasses. The tin oxide did not liquify in the liquid phase instead stayed in the organic multi-layers, which exfoliated together from the CF glass and TFT glass. This is a huge advantage because the organic multi-layers were readily separated by sub-CW and tin was recovered by filtration with ease. Transparent and clean glass was also recovered from LCD panel waste. The amount of tin oxide recovered depended on the sub-CW reaction temperature, reaction time and NaOH concentration. Treatment of smaller CF glass improved the recovery of tin. With this advance, we have showed that sub-CW method is technically feasible for tin oxide recovery in LCD waste.