Fig. 2From: Gold recovery from waste printed circuit boards of mobile phones by using microwave pyrolysis and hydrometallurgical methodsLeaching efficiencies of (A) copper by using different concentrations of sulfuric acid and (B) gold by using thiourea (TU), thiosulfate (TS) and aqua regia (AR). The asterisk symbol represents that the lixiviant was a mixture of sulfuric acid and hydrogen peroxideBack to article page