铝土矿形成过程中元素分异的实验研究

Experimental Research of Elemental Differentiations in the Forming Process of Bauxite

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。

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.