伊毛缟石对蒙脱土和高岭土分散凝聚特性的影响

[目的]探究伊毛缟石对蒙脱土和高岭土分散凝聚特性的影响,为水土保持和环境保护工作提供理论依据。[方法]采用浊度法测定黏土的分散性、离子交换法测定黏土电荷特性、电子显微镜观察等实验方法,将蒙脱土和高岭土溶液分别按一定比例混合伊毛缟石溶液,观察伊毛缟石对蒙脱土和高岭土分散凝聚特性的影响。[结果]伊毛缟石和蒙脱土的1∶1混合溶液,在全部pH值范围内保持凝聚;未脱铁处理的高岭土在pH值为5.9以下凝聚,在pH值为6.0以上分散,添加约5%的伊毛缟石使它的分散凝聚特性逆转。[结论]从微观上看,无论在酸性还是碱性条件下,伊毛缟石混合溶液都呈凝聚状态。酸性时,伊毛缟石的可变电荷和结晶性黏土矿物的永久电荷之间的引力形成凝聚;碱性时,伊毛缟石的表面变成中性形成凝聚。

Effects of Imogoliteon on Colloidal Stability of Montmorillonite and Kaolinite

[Objective] Exploring the influence of imogolite on the dispersion and coagulation characteristics of montmorillonite and kaolinite, to provide a theoretical basis for soil and water conservation and environmental protection work.[Methods] Montmorillonite and kaolinite solutions were respectively mixed with a certain proportion of imogolite solution. After that, turbidimetric method and ion exchange method were used for the measurements of the dispersion of clay and charge characteristics of clay; and electronic microscope was used to observe the effect of imogolite on the dispersion & flocculation characteristics of montmorillonite and kaolinite.[Results] The mixture kept coagulated in any pH value when imogolite and montmorillonite was mixed in a of proportion of 1:1; solution of Kaolin without iron removal processing was observed agglomerated when pH value was below 5.9 but dispersed when pH value was more than 6.0. The aggregation characteristics of kaolin without iron removal processing reversed when about 5% of imogolite was added.[Conclusion] From the microscopic point of view, imogolite mixed solution was in coagulated state whether in acidic or alkaline condition. When the solution of imogolite was acidic, it agglomerated because of the gravitational coagulation between variable charge of itself and the permanent charge of clay crystallinity minerals; when the solution was alkalinity, the surface of imogolite became neutral and agglomerated.