Sustainable recycling of pure aluminum from waste chips under supergravity-enhanced separation: A cleaning process

Abstract

Large quantities of chips containing high levels of aluminum are always inevitably produced during machining process of aluminum products, which is a valuable renewable resource. In this paper, an environmental-friendly method for direct and continuous recovery of same-level recycled Al from waste chips under supergravity-induced was proposed. The oxide film covering the surface of the molten Al-chips was easily disrupted under super-gravity, and subsequently almost all of Al melt detached from the oxide film and flowed rapidly through the microporous ceramic foam filter, with a yield ratio of more than 97 %. During this process, all fine broken oxide-film particles and large amounts of primary iron-rich particles in the melt were captured in the complex channels of the filter, resulting in clean 1xxx series recycled Al with free inclusions and impurity iron content of less than 0.28 wt%. In addition, a sustainable process and a continuous centrifugal unit for recycling aluminum chips were designed, the economic and environmental advantages of which demonstrate the feasibility of sustainable regeneration of aluminum chip resources on an industrial scale via supergravity technique.