Optimisation of extraction of valuable metals from waste LED via response surface method

Abstract

AbstractThe valuable metals were separated and extracted from waste light-emitting diodes (LEDs) by pyrolysis and leaching process. About 98.16% Ga and 99.54% Y were recycled from the LEDs after the pyrolysis by sieving process in advance. The effects of various leaching conditions on the extraction of Fe, Cu and Ag were investigated by single factor experiments and response surface method. About 90.15% Fe was selectively extracted from the waste LEDs by H2SO4 leaching without oxidant, and 99.55% Cu and 99.36% Ag were recovered from the iron leaching residue by acid leaching with the addition of HNO3. The XRD and SEM−EDS analyses confirmed that the iron and copper were effectively extracted from the waste LEDs by the developed process.