“Urban Mines” Recycling in Astec-irie Co., Ltd.

Abstract

This paper reviews recycling technologies in Astec-irie Co., Ltd. Repellent substances and valuable metals, such as precious metals and rare metals, contained in waste electronics were separated and concentrated using superheated steam, an aqueous iron (III) chloride solution, and AI. The electronic components and substrates were separated by melting the solder with superheated steam, and the repellent substance in noniron smelting was removed from them. The gold-plated parts contained in the electronic components were separated back into gold by dissolving the copper and nickel in the aqueous iron (III) chloride solution. The copper and nickel dissolved into the solution were separated and recovered respectively as solid components by adding iron powder. The useful metals were concentrated from the separated electronic components, which are sorted out using AI. As a result, valuable metals such as precious metals could be concentrated while reducing the concentration of repellents, thus making it possible to treat the removed repellents as useful substance.