摘要
高岭石矿物在自然界的形成途径可归纳为四种:①长石经绢云母中间阶段形成高岭石矿物;②长石直接转化成高岭石矿物;③从溶液中直接沉淀出高岭石矿物;④由胶体晶化作用形成高岭石矿物。本文通过以参加形成高岭石矿物各组分的热力学参数为基础,建立pH—logαK^+,logαH_4SiO_4—logαK^+/αH^+,logαCa^(2+)/α~2H^+—logαK^+/αH^+等图解,对不同方式形成高岭石的热力学条件进行了解释。分析表明,高岭石矿物形成与稳定取决于pH值、水介质中阳离子的种类和离子浓度。温度的增加可加速高岭石矿物的形成。
It is concluded that Kaolinite minerals can be formed in the nature in four different ways: 1) transformation of feldspar into kaolinite through an intermediate sericite stage; 2) direct transformation of feldspar into kaolinite; 3) direct precipitation of kaolinite from the solution; 4) formation of kaolinite by collid crystallization. In this paper, pH—logα_(K^+),logα_(H_4)SiO_4—logα_(K^+)/α_(H^+),logα_(Ca)^(2+)/α~2H^+—logα_(K^+)/α_(H^+) diagrams are established on the basis of thermodynamic parameters of various components involved in the formation of kaolinite minerals and the thermodynamic conditions for the formation of kaolinites in different ways are explaned. It is shown that the forming and stabilization of kaolinites is mainly dependant on pH, cation type in hydrous medium and ion concentration. The temperature increase may speed up the forming of kaolinite minerals.
