A physicochemical model of gallium behaviour in the weathering profile

Abstract

Introduction: The article presents original and literature data on the standard Gibbs free energy of 23 gallium ions and complexes in an aqueous solution, as well as its three possible mineral phases. Methodology: "Selector" program and a method of physicochemical computer modelling were used to analyse gallium behaviour in the process of phyllitic schist weathering. Results and discussion: The content of Ga in schists was similar to its average content in the earth's crust and was equal to 103 weight %. It was established that in the weathering profile gallium is stored as a solution of Ga(ОH)30, Ga(ОH)4- (predominant), and Ga(ОH)52- hydroxocomplexes. Conclusions: Gallium can occur in the oxidation zone, however, in very small quantities, due to its isomorphism with aluminium and entering the gibbsite lattice. In the reduction zone of the profile Ga2S3 sulphide may occur.