PHYSICOCHEMICAL MECHANICS OF MICROSTRUCTURAL TRANSFORMATIONS OF SWELLING CLAY MINERALS

An original model of microstructural transformations during swelling of clays is considered, and a thermodynamic and physical-mechanical description of the specifi c features of clays in the process of swelling in vapors and aqueous solutions is given. The model proposed to explain these properties is based on the idea of mutual movement of clay particles in clay rock aggregates during swelling with the formation of new pores between clay particles forming crystallites and aggregates. The model is based on a mechanism of utilizing excess surface energy of clay particles with account for the infl uence of certain parameters of the medium, for example, solution concentration, through a change in the mutual orientation of clay particles, mainly due to rotations or shifts relative to each other with the formation of a free surface available for further wetting. In a thermodynamic description, such a process will manifest itself in a change in the energy of surface interaction on the wetted areas of particles when moving during mutual shifts and rotations. Changing in this case is also one of the most important parameters of the clay rock — microporosity. In this work, this phenomenon was studied experimentally using the methods of static moisture capacity and Mössbauer (gamma-resonance) spectroscopy. The proposed model makes it possible to explain the features of the clay swelling process and compare the observed experimental data with the theoretical description of the clay swelling process.
An original model of microstructural transformations during swelling of clays is considered, and a thermodynamic and physical-mechanical description of the specifi c features of clays in the process of swelling in vapors and aqueous solutions is given. The model proposed to explain these properties is based on the idea of mutual movement of clay particles in clay rock aggregates during swelling with the formation of new pores between clay particles forming crystallites and aggregates. The model is based on a mechanism of utilizing excess surface energy of clay particles with account for the infl uence of certain parameters of the medium, for example, solution concentration, through a change in the mutual orientation of clay particles, mainly due to rotations or shifts relative to each other with the formation of a free surface available for further wetting. In a thermodynamic description, such a process will manifest itself in a change in the energy of surface interaction on the wetted areas of particles when moving during mutual shifts and rotations. Changing in this case is also one of the most important parameters of the clay rock — microporosity. In this work, this phenomenon was studied experimentally using the methods of static moisture capacity and Mössbauer (gamma-resonance) spectroscopy. The proposed model makes it possible to explain the features of the clay swelling process and compare the observed experimental data with the theoretical description of the clay swelling process.
Author:  M. G. Khramchenkov, F. A. Trofi mova, R. É. Dolgopolov
Keywords:  clay rocks, crystallites and aggregates, microporosity, clay swelling, low permeability
Page:  315