Recovery of gold from waste electrical and electronic equipment (WEEE) using ammonium persulfate

This paper presents a novel methodology to recover gold from waste electrical and electronic equipment (WEEE) using ammonium persulfate ((NH4)(2)S2O8). Gold was recovered as a fine coating using substrate oxidation without shredding or grinding process. The WEEE sample was characterized giving values of Au: 1.05 g/kg, Fe: 86.00 g/kg, Ni: 73.64 g/kg, Cu: 26.65 g/kg. The effect of (NH4)(2)S2O8 concentration (0.22-1.10 M), oxygen (0.0-1.4 L/min) and L/S ratio (10-30 mL/g) on the main responses (substrate oxidation and Au recovery) was investigated implementing response surface methodology with numerical optimization. A quadratic model was developed and quantities greater than 98% of Au were recovered. The findings presented suggest that, optimized quantities of ammonium persulfate in aqueous highly oxygenated media could be used to extract superficial gold from WEEE. (C) 2016 Elsevier Ltd. All rights reserved.