The possibility of Rare Metal Recovery from white LED Bulbs

White LED bulbs – dominant in lighting technology – can become a significant secondary source for the recovery of valuable rare metals, if a proper extractive metallurgical technology is developed. We have found an efficient way to separate the “phosphors” (phosphor coated LED chips) from the metallic base shells in dilute sodium carbonate and calcium hydroxide solutions. The leaching reactions of the separated phosphors was studied thermodynamically and the process was examined experimentally. The contained base metals and rare earth elements could be efficiently leached in 1 M HCl acid in 1 h, only Ga and In showed inert behavior toward acid solubilization. The separation of the valuable components has been devised by standard hydrometallurgical techniques.