US 12,006,225 B2
Bayer process
Neil Hofstee, Brisbane (AU); Alistair Gillespie, Mount Crosby (AU); Tomas Mach, Brisbane (AU); and Warren Staker, Indooroopilly (AU)
Assigned to Rio Tinto Alcan International Limited, Montreal (CA)
Appl. No. 16/971,379
Filed by Rio Tinto Alcan International Limited, Montreal (CA)
PCT Filed Feb. 22, 2019, PCT No. PCT/AU2019/050152
§ 371(c)(1), (2) Date Aug. 20, 2020,
PCT Pub. No. WO2019/161455, PCT Pub. Date Aug. 29, 2019.
Claims priority of application No. 2018900584 (AU), filed on Feb. 23, 2018.
Prior Publication US 2021/0009435 A1, Jan. 14, 2021
Int. Cl. C01F 7/473 (2022.01); B01J 20/18 (2006.01); C01F 7/145 (2022.01); C01F 7/147 (2022.01)
CPC C01F 7/473 (2013.01) [B01J 20/18 (2013.01); C01F 7/145 (2013.01); C01F 7/147 (2013.01); B01J 2220/4887 (2013.01)] 15 Claims
OG exemplary drawing
 
15. A Bayer process for dissolving alumina contained in bauxite comprising controlling the concentration of oxalates in solution in Bayer liquor in a red side of the process to be as high as possible to drive oxalate removal from Bayer liquor in the red side of the process without resulting in oxalate precipitation in a precipitation step in a white side of the process, the process including: adding a reagent to Bayer liquor to minimize oxalate precipitation in the precipitation step in the white side of the process, controlling a bauxite reactive silica concentration in Bayer liquor to facilitate removal of oxalates from solution in Bayer liquor in the red side of the process, controlling and removing oxalates from solution in Bayer liquor in the red side of the process by absorbing oxalates into bauxite residues produced in the red side of the process and separated from Bayer liquor in the red side of the process.