Structure,Morphology And Properties Of Montmorillonite- Palygorskite Composite Clay

In this paper,sodium-montmorillonite from Liaoning-Kazuo,and palygorskite from Jiangsu-Xuyi as the raw material,a series of different compound ratio of montmorillonite-palygorskite composite clay samples has been prepared.The structure,morphology,physical and chemical properties of composite clay has been studied by X-ray diffraction,transmission electron microscope,electron microscope,Zeta potential analysis,rotational viscometer.On the basis,the composite ratio of montmorillonite: palygorskite = 9:1 was selected as the research object,and the effect of acidity on the structure,morphology,physical and chemical properties and application properties of the composite clay was systematically studied.It is found that with the increase of the proportion of palygorskite in the composite clay,the dissociation degree of crystallization of montmorillonite decreases and the dispersion degree.When Mt:Pal=1:9,Mt and Pal form a "crosslink point" as the center of Mt.The viscosity of the composite sample at this proportion point reaches the maximum and exceeds the viscosity of the single-component clay,while the viscosity of other proportion composite clay is lower than that of the single-component clay.The absolute value of Zeta potential and suspension stability were positively correlated with the content of montmorillonite,while the wettability was negatively correlated.The salt resistance of the composite clay was positively correlated with the content of montmorillonite in 0.5% NaCl solution,and positively correlated with the content of poriolite in 2% NaCl solution.The mass ratio of Mt:Pal=9:1 was selected to study the effect of acidity on the composite sample.The results showed that in the range of pH value from 1 to 13,with the increase of pH value,the composition of montmorillonite and palygorskite basically have no change,and the dissociation and dispersion degree of montmorillonite sheets,the separation and dispersion degrees degree of fiber cluster of palygorskite and the absolute value of Zeta potential all gradually increased with the increase of pH value from 1 to 13.The viscosity of the palygorskite samples increased first and then decreased.The viscosity of montmorillonite and the composite viscosity sample gradually increased,and increased rapidly after pH>12.When pH 13,reached the maximum value of 9151mPa·s,and the viscosity of the composite clay sample was smaller than that of the corresponding pH of montmorillonite.After discussing the clay composite ratio and action mechanism of acidity on the composite clay,it is concluded that the gelation property of composite clay is influenced by three factors: the separation and dispersion degree of montmorillonite and palygorskite,the surface potential of montmorillonite and palygorskite,and the size of sheets and fibers.The composite ratio and acidity of the composite clay affect the structure,morphology and surface electricity of the composite clay particles,and then affect the degree of separation,dispersion and surface potential,so that the gel properties change significantly.