title: Effects of thermal treatments on the characterisation and utilisation of red mud with sawdust additive.
abstract: Extremely large amounts of red mud (bauxite residue) are generated globally every year from alumina refining industries, which are being disposed of on engineered landfills. The objective of this study is to investigate the effects of thermal treatments on red mud for development of utilisation strategies. Thermal treatments of red mud samples and their characterisations were investigated under inert (N2) and oxidative (air) conditions with and without sawdust addition at 200-600°C. After calcination, the resulting samples were analysed using thermogravimetric-infrared spectroscopy (TG-IR) for functional group transformations, thermogravimetric analysis (TGA) for thermal loss profiles and X-ray diffraction (XRD) for mineral transformations. The characterisation results showed that in N2 environment, boehmite in red mud was transferred to transition alumina at around 400°C while losing water from structural components. The addition of sawdust for incubation and calcination of red mud in air increased the surface area, whereas that in nitrogen atmosphere lead to reduction of hematite to magnetite at around 500°C. The incorporated carbon materials played a major role in increasing the surface area especially for pore size less than 2.5 nm. This treated red mud with altered mineral composition and improved properties for binding contaminants can be used for environmental remediation and in the process of metal recovery such as iron.
authors.affiliation: Global Center for Environmental Remediation, Faculty of Science and Information Technology, University of Newcastle, Newcastle, Australia CRC for Contamination Assessment and Remediation of the Environment, Environmental Science Building, Mawson Lakes, Adelaide, Australia.
authors.forename: Yanju
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Global Center for Environmental Remediation, Faculty of Science and Information Technology, University of Newcastle, Newcastle, Australia CRC for Contamination Assessment and Remediation of the Environment, Environmental Science Building, Mawson Lakes, Adelaide, Australia ravi.naidu@newcastle.edu.au.
authors.forename: Ravi
authors.initials: R
authors.lastname: Naidu
authors.affiliation: Centre for Environmental Risk Assessment and Remediation, University of South Australia, Mawson Lakes Campus, Australia.
authors.forename: Hui
authors.initials: H
authors.lastname: Ming
authors.affiliation: Global Center for Environmental Remediation, Faculty of Science and Information Technology, University of Newcastle, Newcastle, Australia CRC for Contamination Assessment and Remediation of the Environment, Environmental Science Building, Mawson Lakes, Adelaide, Australia.
authors.forename: Rajarathnam
authors.initials: R
authors.lastname: Dharmarajan
authors.affiliation: Global Center for Environmental Remediation, Faculty of Science and Information Technology, University of Newcastle, Newcastle, Australia CRC for Contamination Assessment and Remediation of the Environment, Environmental Science Building, Mawson Lakes, Adelaide, Australia.
authors.forename: Jianhua
authors.initials: J
authors.lastname: Du
mesh_terms: D000536:Aluminum Hydroxide / Q000737:chemistry; D000537:Aluminum Oxide / Q000737:chemistry; D001315:Australia; D019652:Extraction and Processing Industry / Q000379:methods*; D005290:Ferric Compounds / Q000737:chemistry; D007220:Industrial Waste / Q000032:analysis; D013055:Spectrophotometry, Infrared; D013696:Temperature; D013818:Thermogravimetry; D018505:Waste Management / Q000379:methods*; D014934:Wood; D014961:X-Ray Diffraction
chemical_list: D005290:Ferric Compounds; D007220:Industrial Waste; C000499:ferric oxide; D000536:Aluminum Hydroxide; C069471:aluminum oxide hydroxide; D000537:Aluminum Oxide
keywords: Red mud; adsorbent; characterisation; iron recovery; thermal treatment; utilisation