Indium recovery from discarded LCD panel glass by solvent extraction

Indium is one of the key components in an LCD. In this work a potential recycling method involving leaching and solvent extraction was studied. Leaching of crushed LCD glass was investigated using HCl, HNO3, or H2SO4. Results of leaching kinetics showed that nearly complete leaching of indium can be achieved using 1 M HCl and 1 M H2SO4 in less than 8 h. A screening test was performed for the extraction and separation of indium from HCl or H2SO4 with DEHPA, TBP, and Cyanex 272 or Cyanex 923. More than 99% of indium from the aqueous feed can be recovered with a purity of 90%, by extracting metal ions from 1 M or 0.1 M H2SO4 to 0.1 M DEHPA diluted in kerosene, and back-extracting with 1 M HCl.