Hydrometallurgical Recovery of Indium from Flat-Panel Displays of Spent Liquid Crystal Televisions

Abstract

A recovery process for indium from waste liquid crystal display panels was developed on the basis of hydrometallurgical technology. The powdered sample was leached with 3 M HCl to extract its various metal constituents (indium, aluminum, tin, etc.). The mutual separation and subsequent recovery of the dissolved metals was achieved using two column adsorption tests: The first column was packed with a porous resin impregnated with Aliquat 336, a commercially available solvent extraction reagent based on a quaternary ammonium compound, and the resin contained in the second column was impregnated with Cyanex 923, also a commercially available solvent extraction reagent based on trialkylphosphine oxide. In the first column, tin, iron, and zinc were removed from the leach liquor. In the second column, only indium was selectively recovered. The metal ions trapped in these columns were eluted with 0.1 M H2SO4, yielding a solution purified indium solution with a concentration 10 times that of the feed solution.