title: Enrichment of Sc2O3and TiO2from bauxite ore residues.
abstract: As a major byproduct generated in the alumina industry, bauxite ore residue is an important reserve of scandium and titanium. In this study, the feasibility and mechanism of enriching Sc2O3and TiO2from a non-magnetic material, which was obtained from carbothermal reductive roasting and magnetic separation of bauxite ore residue, were investigated based on a two-step (acidic and alkali) leaching process. It was revealed that approximately 78% SiO2and 30-40% of CaO, FeO and Al2O3were removed from a non-magnetic material with 0.0134wt.% Sc2O3and 7.64wt.% TiO2by phosphoric acidic leaching, while about 95% Al2O3and P2O5were further leached by subsequent sodium hydroxide leaching of the upper-stream leach residue. A Sc2O3-, TiO2- rich material containing 0.044wt.% Sc2O3and 25.5wt.% TiO2was obtained, the recovery and the enrichment factor of Sc2O3and TiO2were about 85% and 5, respectively. The enrichment of Sc2O3was attributed to higher pH (>3.3) of phosphoric acid solution than its dissolution pH0, and the enrichment of TiO2was mainly associated with the insoluble perovskite (CaTiO3) in the acidic solution at ambient temperature. As Sc2O3and TiO2cannot be dissolved in the alkali solution, they were further enriched in the leach residue.
authors.affiliation: School of Minerals Processing & Bioengineering, Central South University, Changsha, Hunan 410083, China.
authors.forename: Bona
authors.initials: B
authors.lastname: Deng
authors.affiliation: School of Minerals Processing & Bioengineering, Central South University, Changsha, Hunan 410083, China. Electronic address: liguangh@csu.edu.cn.
authors.forename: Guanghui
authors.initials: G
authors.lastname: Li
authors.affiliation: School of Minerals Processing & Bioengineering, Central South University, Changsha, Hunan 410083, China.
authors.forename: Jun
authors.initials: J
authors.lastname: Luo
authors.affiliation: School of Minerals Processing & Bioengineering, Central South University, Changsha, Hunan 410083, China.
authors.forename: Qing
authors.initials: Q
authors.lastname: Ye
authors.affiliation: School of Minerals Processing & Bioengineering, Central South University, Changsha, Hunan 410083, China.
authors.forename: Mingxia
authors.initials: M
authors.lastname: Liu
authors.affiliation: School of Minerals Processing & Bioengineering, Central South University, Changsha, Hunan 410083, China.
authors.forename: Zhiwei
authors.initials: Z
authors.lastname: Peng
authors.affiliation: School of Minerals Processing & Bioengineering, Central South University, Changsha, Hunan 410083, China.
authors.forename: Tao
authors.initials: T
authors.lastname: Jiang
keywords: Alkali leaching; Enrichment; Phosphoric acid; Sc(2)O(3); TiO(2)