Beneficiation of Ga from alunite concentrates by selective acid leaching and alkaline precipitation

In this study beneficiation of Ga from alunite ore was investigated. The effects of the calcination temperature, H₂SO₄ concentration, leaching temperature and liquid-solid ratio on the dissolution characteristic of Ga, K and Al were studied. The results showed that increasing the calcination temperature, H₂SO₄ concentration and leaching temperature can improve the solubility of K and Al. However, higher H₂SO₄ concentration and lower leaching temperature can improve the dissolution of Ga, which was beneficial to recovery of Ga. On the basis of the solubility difference in H₂SO₄, a two-stage process of selective acid leaching and alkali precipitation of Ga was proposed. The concentration of Ga was increased significantly from 54 g/t in alunite ore to 4100 g/t in alkali precipitation product. The major elements of Al and K in alunite were recovered as the alum crystal with a purity of 99.62%.