Comparative smelting of thermally pretreated electronic waste

Abstract

Used electronic inverters were processed thermally to eliminate organic matrix components through oxidative incineration (IN), oxidative steam gasification (SG), and pyrolysis (PY). Such prepared material was melted at 1250°C with sodium/calcium silicate waste glass under reductive and oxidative atmospheres. The highest Cu recovery in the form of a gravitationally separated metallic phase was found for oxidative smelting of the PY sample and reductive smelting of the IN sample. Recovery of precious metals was analyzed, taking Cu recovery as the reference. It was found that the recovery of Pd was better than copper recovery in each experiment, and the recovery of Au was only in the oxidative smelting of the SG sample and reductive smelting of the IN sample. Recovery of Ag and Cu was similar but only for the reductive smelting of the PY and SG samples. It was demonstrated that Cu, as well as Au, Ag, and Pd recovery, substantially depends on the transport of metals through the metal/slag interface.