Thiourea Leaching: An Update on a Sustainable Approach for Gold Recovery from E-waste

Abstract Electronic waste is a dominant global issue with over 50 million tons generated annually. Still, as an amalgamation of precious and rare raw materials, electronic considerable economic resource the most valuable components located on printed circuit boards. Gold widely used in electronics numerous applications, although principally for contact points external connectors. The recovery gold, due to its high value, one main motivations recycling e-waste. Although pyrometallurgy hydrometallurgy processing are still preferred modes use high-energy consuming pyro-methods, gold cyanidation that uses harmful lixiviants increasingly discouraged. Thiourea has received attention alternative lixiviant leaching fast reaction kinetics less nature. This review aims provide up-to-date evaluation thiourea-gold studies from waste, emphasis recent progression classic chemical method more sustainable hybrid bioleaching-based system, while challenges highlighted. complementary methods applied retrieval pregnant solution also described focus have potential closed-loop key objective material circular economy. Graphical