Feasible conversion of solid waste bauxite tailings into highly crystalline 4A zeolite with valuable application

• Published in: Waste management (Elmsford) Vol. 34; no. 11; pp. 2365 - 2372
• Main Authors: Ma, Dongyang, Wang, Zhendong, Guo, Min, Zhang, Mei, Liu, Jingbo
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01-11-2014; Elsevier
• Subjects: 4A zeolite; ADSORBENTS; Alkali fusion; Aluminum base alloys; Aluminum Oxide - chemistry; Applied sciences; BAUXITE; Bauxite tailings; Bayer process; BY-PRODUCTS; Byproducts; Calcium - chemistry; Calcium carbonate; CALCIUM CARBONATES; Calcium ion exchange capacity; CALCIUM IONS; CHEMISTRY; CHINA; CONVERSION; CRYSTALLIZATION; ENVIRONMENTAL IMPACTS; Exact sciences and technology; FLOTATION; HEAVY METALS; Industrial Waste - analysis; INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; Ion Exchange; Ion exchangers; MANAGEMENT OF RADIOACTIVE WASTES, AND NON-RADIOACTIVE WASTES FROM NUCLEAR FACILITIES; Mining; Other wastes and particular components of wastes; Pollution; POROUS MATERIALS; Recycling; REMEDIAL ACTION; Solid Waste - analysis; SYNTHESIS; TAILINGS; Wastes; ZEOLITES; Zeolites - chemistry; China, People's Rep; Alkali fusion; Bauxite tailings; 4A zeolite; Crystallization; Calcium ion exchange capacity; Flotation; Decontamination; Environment impact; Reaction product; Solid waste; Zeolite; Ion exchange; Tailings; Public health
• ISSN: 0956-053X; 1879-2456
• DOI: 10.1016/j.wasman.2014.07.012

•Concept to convert waste to valuable product is carried out in this study.•An industrially feasible and cost-effective approach was developed and optimized.•Highly crystalline and well-defined zeolite was produced under moderate conditions.•The zeolite derived from the bauxite tailings displayed high ion exchange capacity.•Bauxite tailings have potential application in heavy metal ions adsorbent.
Bauxite tailings are a major type of solid wastes generated in the flotation process. The waste by-products caused significant environmental impact. To lessen this hazardous effect from poisonous mine tailings, a feasible and cost-effective solution was conceived and implemented. Our approach focused on reutilization of the bauxite tailings by converting it to 4A zeolite for reuse in diverse applications. Three steps were involved in the bauxite conversion: wet-chemistry, alkali fusion, and crystallization to remove impurities and to prepare porous 4A zeolite. It was found that the cubic 4A zeolite was single phase, in high purity, with high crystallinity and well-defined structure. Importantly, the 4A zeolite displayed maximum calcium ion exchange capacity averaged at 296mg CaCO3/g, comparable to commercially-available zeolite (310mg CaCO3/g) exchange capacity. Base on the optimal synthesis condition, the reaction yield of zeolite 4A from bauxite tailings achieved to about 38.43%, hence, this study will provide a new paradigm for remediation of bauxite tailings, further mitigating the environmental and health care concerns, particularly in the mainland of PR China.