Extraction of alumina from the magnetic separation tailings derived from reductive roasting of bauxite residue

Abstract

Much work has been done to recycle iron from bauxite residue via reductive roasting-magnetic separation process, of which more than 85% iron could be recycled as powdered metallic iron, but insufficient efforts have been made to utilize the magnetic separation tailings which were rich in valuable components like aluminum, titanium etc. This study was therefore focused on the alumina recovery from the above-mentioned tailings based on alkali leaching. The effects of the parameters like concentration of leaching agent (NaOH), temperature and time to the extraction of alumina have been investigated. Besides, the influence of the up-stream reductive roasting process and sodium additives on the extraction of alumina have also been studied. The results showed the reductive roasting process was favorable to the extraction of alumina while the sodium additives demonstrated an adverse effect. 82.90% alumina was leached under the optimal conditions from a bauxite residuer containing 19.59 wt. %A120.