Separation and recovery of glass, plastic and indium from spent LCD panels

摘要

The present paper deals with physico-mechanical pre-treatments for dismantling of spent liquid crystal displays (LCDs) and further recovery of valuable fractions like plastic, glass and indium. After a wide experimental campaign, two processes were designed, tested and optimized. In the wet process, 20%, 15% and 40% by weight of the feeding panels are recovered as plastic, glass and indium concentrate, respectively. Instead, in the dry process, only two fractions were separated: around 11% and 85% by weight are recovered as plastic and glass/indium mixture. Indium, that concentrated in the -212 μm fraction, was completely dissolved by sulphuric acid leaching (0.75 mol L~(-1) H_2SO_4 solution, 80 ℃, 10% vol H_2O_2, pulp density 10%wt/vol, leaching time 3 h). 100% of indium can be extracted from the pregnant solution with 5%wt/vol Amberlite™ resin, at room temperature and pH 3 in 24 h. Indium was thus re-extracted from the resin by means of a 2 mol L~(-1) H_2SO_4 solution, at room temperature and S/L of 40% wt/vol.