Water Sorption Properties of Homoionic Montmorillonite

Abstract

Homoionic samples of four montmorillonite clays, selected on the basis of the properties which control their economic uses, were prepared by treating with two normal neutral solutions of ammonium acetate, lithium, sodium, potassium, calcium, and magnesium chloride. Atterberg plastic and liquid limits, slopes of the liquid limit curves, and water sorption curves were determined. Among the results suggested, the following are particularly considered:1.The plastic state is reached when enough water is put into the system to fill all the pore space and to supply all the montmorillonite layers with water adequate for rigid layers plus a slight additional amount.2.The type of cation is not the only factor which controls the properties of montmorillonite.3.The structure of the lattice also appears to determine the properties of montmorillonite.

Influence of smectite content on the deformation behaviour of clay

“…As previously presented, Na + -smectite has a significantly higher volume change potential compared to Ca ++ -smectite. Thus, the Atterberg limits and deformation properties are found to greatly depend on the adsorbed cations (White 1955;Sridharan et al 1986). The change in behaviour can be explained by the diffuse double layer theory (Olphen 1977), which is briefly outlined in the present section.…”

“…The lowest volume change potential is usually found for Ca ++ -smectite and the highest for Na + -smectite (Taylor and Smith 1986). Determining the plastic limit and liquid limit of smectite yields approximately w p = 60-100 % and w L = 125-700 %, respectively, which results in a plasticity index, I p in the range of 50 % to 600 % (White 1955). The large variability in the consistency indices, which may be identified even between two smectites with the same adsorbed cation, may be caused by differences in the crystal lattice, as presented in section 2.4.…”

“…The large variability in the consistency indices, which may be identified even between two smectites with the same adsorbed cation, may be caused by differences in the crystal lattice, as presented in section 2.4. As seen from the range of I p , the effect of adsorbed cation on the smectite mineral is profound for the consistency characteristics (Grim 1962;White 1955).…”

“…Due to strong hydrogen bonds between the individual kaolinite sheets, the expansion of kaolinite usually is quite limited when exposed to water (Taylor and Smith 1986;White 1955). Thus, kaolinite minerals exhibit quite small plasticity indices compared to other clay minerals (White 1955;Trankjaer and Christensen 2012).…”

“…Thus, kaolinite minerals exhibit quite small plasticity indices compared to other clay minerals (White 1955;Trankjaer and Christensen 2012). The plastic limit, w p , and liquid limit, w L , for pure kaolinite minerals, are approximately 30 % and 60 %, respectively, yielding a plasticity index of approximately I p = 30 %.…”