Metal recycling from waste memory modules efficiently and environmentally friendly by low-temperature alkali melts

Abstract

Recycling of waste electrical and electronic equipment has become an urgent global issue in recent years from the prospectives of resources recycling and environmental protection. In the present work, the recycling of waste memory modules (WMMs) through low-temperature alkali melts was investigated, based on the thermodynamic analysis of the nonmetallic reactions of brominated epoxy resin, glass fiber and memory chip with the molten mixed alkali. The effects of the reaction temperature and the ratio of alkali mixture on the removal rate of nonmetallic parts in WMMs were discussed under the condition of air atmosphere. The optimum process parameters were further confirmed by in-situ monitoring of the temperature during the whole reaction process. The mixtures with Cu, Fe and Ni as the main components were obtained after the treatment of WMMs in the molten alkali. These mixed metals were further separated into copper-rich and ferronickel-rich metals by physical magnetic separation. Moreover, the precious metals Au and Ag were enriched in Cu-rich alloys. This work provided an efficient and environment-friendly method for metal recycling from WMMs.