Abstract

This paper investigates the 1-D diffusion process of bentonite particle, which is affected by the friction related to the fractal structure of colloid pore. The expression of the pore tortuosity containing pore fractal dimension is deduced to determine the friction, and the evolution rule of pore fractal dimension during diffusion with bentonite volume fraction is reached. The rationality of the modified fractal model is validated via 1-D diffusion test and nuclear magnetic resonance (NMR). Then the influences of electrolyte concentration, initial volume fraction of bentonite, and surface charge density on the colloid diffusion process are analyzed. The results show that the diffusion of bentonite decreases with the increase of electrolyte concentration, and increases with the increase of initial volume fraction and surface charge density. The interfacial volume fraction is correlated with the concentration of electrolyte solution, but not with the initial volume fraction and surface charge density.

摘要

本文研究了膨润土颗粒的一维扩散过程，该过程受与胶体孔分形结构相关的摩擦力的影响。推导出包含孔隙分形维数的孔隙曲折度表达式来确定摩擦力，得出了孔隙分形维数在扩散过程中随膨润土体积分数的演化规律。通过一维扩散测试和核磁共振（NMR）验证了改进的分形模型的合理性。然后分析了电解质浓度、膨润土初始体积分数和表面电荷密度对胶体扩散过程的影响。结果表明，膨润土的扩散随着电解液浓度的增加而减小，随着初始体积分数和表面电荷密度的增加而增加。