伊利石单元粒子及其研究意义

单元粒子是单晶体构成的细小的粘土颗粒,是由一种或多种层状结构的硅酸盐构成的混层粘土的基本单元。多数伊利石单元粒子以混层晶体的建筑砌块的形式产出,砌块与砌块之间,在 a、b方向通过砌块的边缘界面相砌合而连接,在 c轴方向通过平面界面相砌合而连接。还对伊利石单元粒子的生长机理及形成过程中的形态变化、利用伊利石单元粒子的厚度划分成岩作用阶段等方面的研究成果进行了综述。伊利石单元粒子的形成过程有三个阶段：蒙脱石伊利石化过程中2nm厚的伊利石粒子的成核作用阶段、成核作用与生长作用阶段和表面控制生长阶段。伊利石单元粒子生长过程中,伊利石单元粒子呈现从板状体到条状体的生长,而板状颗粒又呈现各种螺旋生长图案,有圆形、残缺的圆形、多边螺旋、平行阶梯状螺旋、交错螺旋等。伊利石单元粒子的厚度分布服从对数正态型,其峰值为10.5nm。单元粒子与纳米科技两者的主要研究内容和所采用的方法基本一致,建议今后将研究单元粒子与研究纳米粘土矿物学有机地结合起来。

ILLITE FUNDAMENTAL PARTICLE AND ITS SIGNIFICANCES

The fundamental particle is the very fine clay particle composed of single crystal,and is the basic unit of mixed-layer clays formed by one or several kinds of silicates with the sheet structure. Most of illite fundamental particle were found to occur as “building blocks” of mixed-layer crystals（MacEwan crystallites）. Between the “blocks”, the adjacent edges were joined with bonded blocks in a, b direction, and the adjacent surface interfaces are joined with blocks of longer bond in c direction. The recent achievements for illite fundamental particle including the formation mechanisms, the shape variations in the formation process, and the diagenetic stages division were also summarized in the paper. There are three stages in the formation process of illite fundamental particle：①the nucleation stage of 2-nm thick illite particle at the incipient process of montmorillonite illitization; ② the simultaneous nucleation and growth stage  and ③ the surface-controlled growth stage. Illite fundamental particles showed platy to lath shapes. Platy particles exhibited various spiral growth patterns, i.e. circular, malformed circular, polygonal single unit-cell layer spirals, polygonal parallel step spiral, interlaced spiral patterns, etc. The crystal thickness distribution of illite fundamental particle submit to the lognormal-type distribution which maximum value is 10.5nm. Because the major contents and methods of fundamental particle are basic similar to  those in the nanoscience and technology, it is suggested that the relationship between illite fundamental particle and the nano-clay mineralogy be regarded together in future.