Gallium distribution between slag and metal phases during the carbothermal reduction of bauxite

Abstract

This article investigated the recoverability of the Ga in bauxite by carbothermal reduction. Currently, Ga is mostly manufactured from bauxite through the Bayer process as a by-product of alumina, but it is worthwhile to consider alternative processes under stricter environmental regulations and a shortage of high-quality bauxite. This study focused on the Pedersen process, which is the alumina production process consisting of carbothermal reduction and alkaline leaching. The metal and slag phases were prepared by carbothermal reduction of bauxite at 1873 K, and then aluminium in the slag was leached with (Na₂CO₃+ NaOH) solution at 348 K. Evaluation by inductively coupled plasma atomic emission spectroscopy and inductively coupled plasma mass spectrometry revealed that almost all Ga in bauxite was transferred to the metal phase, and the distribution to the slag phase was negligible in carbothermal reduction, which agrees with the thermodynamic consideration. These results suggest that the gallium recovery from pig iron is necessary to produce Ga in the Pedersen process.