Estimation of the annual consumption and in-use stock of gold for small electrical and electronic equipments (EEEs), and the amount of gold contained in discarded EEEs in Japan

Abstract

The recovery of gold from secondary sources like electronic wastes has received much attention because of the many industrial applications and high market prices of precious metal. Electrical and electronic equipments (EEE5) account for approximately 10% of annual demand for gold in Japan as well as in the world. Therefore, waste of EEEs (WEEEs) contains much amount of gold, whose grade can be much higher than that of natural ore. Substance flow analysis (SFA) is a useful tool for determining the flow and in-use stock of substances in specific geographic regions. In this work, we estimated the annual consumption and in-use stock of gold for small EEEs, and the amount of gold contained in discarded EEEs during 1984-20 12. As a result, the maximum amount of consuniption for EEEs production, in-use stock in EEEs and discard in WEEEs were 8.87 tin 2006, 44.5 tin 2005 and 6.90 tin 2008, respectively. Mobile phone accounted for the largest share of the recent consumption and discard of gold, whereas, audio system has accounted for the largest share of the in-use stock for many years. This difference was caused by the average lifetimes and parameters of Weibull distributions for EEEs.