Al-Mg MMH溶胶和钠土悬浮体的相互作用机理

通过流变参数、电泳淌度和pH值的测定,研究了无机盐(CaCl₂、KCl、NaCl)和pH值对铝镁混合金属氢氧化物与钠土悬浮体间相互作用的影响。发现随着混合金属氢氧化物含量的增加,钠土体系的pH值逐渐降低,而动切力(YP)先上升,经最大值后逐渐下降;当钠土体系为NaCl所饱和时,相同混合金属氢氧化物加量下YP的上升幅度明显减小,在实验混合金属氢氧化物浓度范围内,YP未出现峰值。混合金属氢氧化物/钠土体系的YP随pH值的变化曲线呈抛物线形,加入相同浓度的无机盐,△YP、△pH(绝对值)按CaCl₂KCl～NaCl次序递减。

The Interaction Mechanism of Al-Mg MMH Sols with Na-montmorillonite Suspensions

The effects of inorganic salts(NaCl,KCl and CaCl₂)and pHvalues on the interaction between Al-Mg MMHsol(aluminum magnesium mixed metal hydroxides)and Na-montmorillonite(Na-Mt)suspensions have been studied by the measurments of rheology,electrophoretic mobility and pH.The results show that the increase of MMHin Na-Mt suspensions produced an increase in YP(yield point)at first and then a decrease after a maximum but a gradual decrease in pH.The results are interpreted as meaning that the MMHsols can interact with Na-Mt suspensions through an ion exchange mechanism.In the presence of saturated NaCl,a much less change of YPand no YPmaximum under the experimental concentrations of MMH can be explained by DLVOtheory.Due to the effects of pHon ion exchange reaction the change of YPwith pHof MMH/Na-Mt systems is in terms of parabolic curve.Inorganic salts lower YPand pHin the order of CaCl₂>KCl～NaCl,and the order is found to be consistent with that for experimental estimates of the number of unit layers in face-to-face association.This would imply that the metallic ions must function as the exchangeable cations.