Recovery of Strategic Materials from Canadian Bauxite Residue by Smelting Followed by Acid Baking-Water Leaching

摘要

Sustainable sourcing of raw materials is becoming an increasingly important factor to consider in the modern economic and technological landscape. The valorization of bauxite residue, a by-product of the Bayer process for alumina production, offers an opportunity to use a material commonly considered to be a waste stream as an abundant and readily available resource. In this study, a two-step process was developed to extract valuable materials from bauxite residue, employing carbothermic smelting, producing crude metallic iron and a slag phase which concentrates scandium, and other elements of interest, which are then extracted by acid baking-water leaching. Preliminary process tests were carried out, and fundamental investigation and characterizations were used to gain an understanding of the underlying physicochemical mechanisms. This waste valorization process is intended to be integrated into a larger near-zero-waste process to sus-tainably recover the valuable components of bauxite residue to help build the circular economy.