Experimental Research of Elemental Differentiations in the Forming Process of Bauxite

Abstract: On the basis of physicochemical conditions of bauxite forming obtained by geologic analysis, in this paper the dissolving tests of (1) dissolution of A1₂O₃ and SiO₂ of kaoline in the solutions with different pH under oxidizing condition, (2) dissolution of A1₂O₃, SiO₂ and Fe₂O₃ of laterite under the above conditions, (3) dissolution of A1₂O₃, SiO₂ and Fe₂O₃ of laterite in CO₂-H₂O systems with different Eh and pH, (4)dissolu-tion of A1₂O₃, SiO₂ and Fe₂O₃ of laterite in the solutions of different organic acids with different concentration and (5) tentative test of removal of iron from hard clay by means of microorganisms are carried out. Elemental interdifferentiations in the forming process of bauxite and consistency of expremental research with geologic research are discussed. The results show that the interdifferentiation of Fe₂O₃ with A1₂O₃ is not easy under oxidizing condition. Interdifferentiation of SiO₂ with A1₂O₃ is easier in the oxidizing and neutral to weak acid conditions. In reducing conditions, dissolution and transportation of SiO₂ and Fe₂O₃, preservation and concentration of A1₂O₃ are favourable when the system is neutral to weak acid. It is possible that bacteria, organisms, organic acids play important roles in the interdifferentiation of SiO₂ and Fe₂O₃ with A1₂O₃.