The research results show that montmorillonite particles surface adsorption of water, the layer are arranged with rules, the density and viscosity than ordinary liquid water, known as the liquid water.The liquid water and the properties of layers of bentonite had great effects on process performance.Montmorillonite particles on the surface of the adsorption of water features, and the crystal layer q and octahedral cationic exchange of type and amount.Sodium montmorillonite particles on the surface of the liquid water has three molecular layer, smaller than calcium montmorillonite slightly, but from the liquid to liquid water is a gradual shift in the transition layer, 6 ~ 7 times greater than that of calcium montmorillonite.Therefore, sodium based on the swelling has good moisture adaptability, precision casting sand water can reduce the dosage, and the high moisture can still maintain good strength, lost wax casting is reflected in process performance, it has higher thermal wet tensile strength and ability to resist sand inclusion, more suitable for use tend to be larger in sand mold.
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