Abstract:

Thermal-weightlessness is utilized to determine the type boundary line and relative content of bound water on montmoril-lonite and the results of isothermal adsorption have been tom-pared. The results show that each water relative content and total water mass on hydro-montmorillonite场the method are incon-sistent to them by isothermal adsorption. Thermal weight loss a-nalysis ( 25~250`0)results show that water on hydro-mont-morillonite is free water, loose bound water and sirong bound water which respectively corresponding to the water loss in 25-75^oC，75~120^oC，and 120~230^oC.According to thermal-weightlessness regularity(25~250^oC)，it also has two clear turning points which are plp。p/ps=0.9~0.98，the two turning points are the-special humidity of clay一water system. The rela-
five vapor pressure 0. 9 is the boundary line between the strong bound water and the loge bound water(osmotic bound water ) on clays, the relative vapor pressure 0. 98 is the boundary line between the loge bound water and free water on clays. The method verifies the "two special humidity" by isothermal adso p-lion and the boundary line of bound water on clays.

Key words: hydro clay, thermal weightlessness, bound water, relative content, special