Recovery of alkali and alumina from bauxite residue (red mud) and complete reuse of the treated residue. (1st July 2018)

• Record Type: Journal Article
• Authors: Wang, Yanxiu; Zhang, Ting-an; Lyu, Guozhi; Guo, Fangfang; Zhang, Weiguang; Zhang, Yuhai
• Is Part Of: Journal of cleaner production. Volume 188(2018)
• Page Start: 456
• Page End: 465
• Publication Date: 2018-07-01
• Subjects: Bauxite residue -- Calcification-carbonisation process -- Alkali and alumina recovery -- Complete reuse; Factory and trade waste -- Management -- Periodicals; Manufactures -- Environmental aspects -- Periodicals; Déchets industriels -- Gestion -- Périodiques; Usines -- Aspect de l'environnement -- Périodiques; 628.5
• DOI: 10.1016/j.jclepro.2018.04.009
• Languages: English
• ISSNs: 0959-6526

Abstract

Abstract: Bauxite residue is an alkaline solid waste produced during the extraction of alumina from bauxite, which causes serious environmental problems and safety risks. In this study, alkali and alumina were recovered from Bayer bauxite residue using a novel calcification-carbonisation process. This produced a non-hazardous and near-neutral residue (C-C residue), the properties of which facilitated its subsequent reuse. After the calcification-carbonisation treatment, 46.5% of the alumina was extracted and the Na2 O content in the final residue (C-C residue) dropped to less than 0.3%. In addition, the feasibility of using C-C residue in the production of cement and the preparation of soil was analysed. The results showed that the chemical composition of C-C residue is very close to that of Portland cement clinker, which allows the dosage of bauxite residue in cement production to be increased. A comparison of the C-C residue with a general soil showed that the former performed well for many soil parameters, such as alkalinity and salinity, and has great potential for application in soil preparation. Thus, the calcification-carbonisation method, combined with cement production or soil preparation, is a sustainable process for completely reusing Bayer bauxite residue and facilitating bauxite waste minimisation. Graphical abstract: Highlights: A novel C-C process was proposed to recover alkali and alumina from Bayer bauxite residue. Bauxite residue was transformed structurally into a near-neutral and nonhazardous residue. The potential use of C-C residue was analysed based on a series of characteristic contrasts. Extracting metals first and then reusing residue was proposed to realise zero discharge.