Options for using electronic waste as an alloy resource: dilution with Al scrap

Abstract

The increasing use of electronic appliances has resulted in millions of tons of outdated devices and electronic waste, a small percentage of which is recycled. This work focuses on opening new gates by using electronic waste as an alloy source to produce important industrial alloys rather than using pure elements, which results in the depletion of earth resources and environmental hazards. The samples studied were prepared by diluting the waste (metal constituents) into scrap aluminum (Al)-based alloys. The microstructures, phase characterization, and chemical or elemental analyses of the prepared samples were investigated. The results of the chemical analysis showed an increase in the content of some elements such as silicon (Si), iron (Fe), chromium (Cr), copper (Cu), and nickel (Ni) compared to the initial Al-base charge main constituent, proving the formation of complex solid solutions. Throughout the study, the microstructural and phase analyses showed the formation of rhombic dodecahedron primary α-AlFeCrSi phase instead of the needle-shaped β-Al5FeSi. This can be explained by the presence of Cr (added from waste) that can eliminate the harmful effects of the primary Fe-rich intermetallic phases by transforming those into solid solutions.