铝土矿形成过程中元素分异的实验研究

根据铝土矿形成的物化条件,本文进行了有关条件下高岭土和红土中硅、铝、铁的溶解试验,讨论了铝土矿形成过程中元素的分异作用及实验研究与地质研究的一致性。结果表明,氧化条件下,铁铝不易分异;在中偏酸性时,硅铝较易分异。还原条件下,中偏酸性时,有利于硅和铁的溶解迁移和铝的保存富集。在硅、铁和铝的分异过程中,细菌、有机质和有机酸可能起着重要作用。

Experimental Research of Elemental Differentiations in the Forming Process of Bauxite

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.