凹凸棒石粘土沉降分散行为研究

Deposition and Dispersion of Attapulgite Clay

采用重力沉降分析法研究了酸碱度、表面活性剂、溶剂等对凹凸棒石粘土沉降分散行为的影响,并进行了理论分析.研究表明,溶液的pH、表面活性剂浓度和分散介质类别均影响凹凸棒石粘土的沉降分散行为;凹凸棒石粘土表面及介质的极性变化是凹凸棒石粘土沉降分散行为改变的重要因素.凹凸棒石粘土的沉降分散行为具有规律性:即溶液的酸碱电解质浓度越大,凹凸棒石粘土分散稳定性越好.分散介质的极性越大,凹凸棒石粘土的分散状况越好.表面活性剂能明显促进凹凸棒石粘土在低介电常数有机介质中的分散状况,高浓度的表面活性剂促进凹凸棒石粘土分散及其稳定性的增强.凹凸棒石粘土表面及介质的极性增大会使凹凸棒石粘土粒子间斥力增强,促进粒子破碎,改善粒子的粒径分布,同时使粒子在电斥力作用下分散稳定性增高.

A gravitational depositional experiment was established to study the effects of acidity, surface-active agent and solvent on sedimentation and dispersional behavior of attapulgite clay in various media. The results shows that pH values of solution, concentration of surface-active agent and the kind of solvent can efectively influence the dispersional behavior of attapulgite particles. The variation of the polarities of the attapulgite surface and the media is the main reason that causes changes of depositional and dispersional behaviors of the attapulgite particles. It is clear that the higher the concentration of acid or alkaline electrolytes, the better the dispersional stability, and the stronger the polarity of dispersants, the better the dispersional stability. Surface-active agents can probably facilitate the decentralization of attapulgite clay in organic dispersants with low dielectric constant, and thus the comparatively high concentration of surface-active agents is crucial to the decentralization of attapulgite clay. The polarity augmentation of either the attapulgite surface or the media will increase the strong repulsive power, which facilitates the crush of the particles, thus improving the distribution of particle bulk. At the same time, the action of electronic repulsive power heightens the suspension stability of attapulgite solution.