To the problem of the clay particles energy potential assessment

Clay is a natural material, which surface of the particles is energetically active. This clay property is widely used in the industry as sorbents. However, clay sorption activity is different for various pollutants, and work aimed to increase their sorption activity is still under way. This work objective was to study the pressure influences on the activity of the clay particles surface. The experiments showed that increase of pressure results in the decrease in the content of clay minerals, while other minerals change in different manner. It has been statistically proved that pressures P = 125 MPa and P = 750 MPa are bounding values that allows identifying the three classes. The first class is related to the pressures under 125 MPa, the second comprises the range from 125 MPa to 750 MPa, and the third class is for the pressures above 750 MPa. In each class, the intensity and direction of the proceeding of processes of mineral clay composition alteration have specific features. Based on theoretical and experimental studies it was established that the less the value of indicator Mk, the higher the energy potential of the particle surface. It achieves the maximum values (Mk = 14.7) in montmorillonite clay under pressure of 125 MPa, and, conversely, with an increase in pressure up to 2200 MPa the Mk value decreases (Mk = 17.7). A different behavior was observed in kaolinite clay. The energy potential on the particle surface increases with an increase in pressure from Mk = 26.3 to Mk = 18.8 (P = 2000 MPa). Mathematical models, which make it possible to predict energy potential on the surface of montmorillonite and kaolinite particles depending on the pressure, have been developed based on the found statistical relations.