Abstract:

The increment of sodium montmorillonite crystalline interspace caused by tap water is greater than KCl, NaCl, CaCl2 solutions with different salinities; adding different types of salts into water can stabilize sodium montmorillonite clay mineral and inhibit the expansion of crystalline interspace. The increments of crystalline interspace affected by different salinities and types of solutions are different. Comparing three kinds of solution KCl, NaCl, CaCl2, the variation caused by KCl solution is the least; the crystalline interspace variation is only 1.32% under the saturated KCl solution. When sodium montmorillonite contacts with different types of solution, the crystalline interspace increment decreases and gradually tends to be stabilized with the increasing of solution dosage. The hydrate expansion capacity of sodium montmorillonite has no direct relationship with the total solution dosage; when the clay mineral is soaking in water, interspace will not expand unlimitedly as the increase of the total volume of water. When contacted with the same dosage but different types of solution, the crystalline interspace changes as complex exponential function with the increase of contact time; in shows the characteristic of mutation increasing in the initial stage and quickly tending to be stabilized.

Key words: sodium montmorillonite, salt solution, soak, dosage, crystalline interspace