Alkali roasting of bomar ilmenite: rare earths recovery and physico-chemical changes

• Published in: Open Chemistry Vol. 13; no. 1
• Main Authors: Sanchez-Segado, Sergio, Lahiri, Abhishek, Jha, Animesh
• Format: Journal Article
• Language: English
• Published: De Gruyter Open 01.01.2015; De Gruyter
• Subjects: Leaching; Rare Earth oxides; Selective separation; Synthetic Rutile; Titanium
• DOI: 10.1515/chem-2015-0033
• ISSN: 2391-5420

In this work, the alkali roasting of ilmenite (FeTiO ) is presented as a process route for integrated beneficiation of the mineral for rutile-rich phase and rare earth oxides; the latter is released as a consequence of physical changes in the ilmenite matrix, during the water leaching after roasting. The oxidative alkali roasting transforms ilmenite mineral into water-insoluble alkali titanate and water-soluble ferrite. After roasting the insoluble alkali titanate is separated from rare-earth oxide mixture in colloidal form and water-soluble ferrite. Further leaching of alkali titanate is carried out with oxalic (0.3M) and ascorbic (0.01M) acid solution which removes the remaining Fe ions into the leachate and allows precipitation of high-purity synthetic rutile containing more than 95% TiO . Iron is removed as iron oxalate. The physico-chemical changes occurred during the roasting and leaching processes are reported by comparing the role of alkali on the roasting process and product morphologies formed.