Structural modification of fine powders of overburden rocks of saponite-containing bentonite clay

The kinetic regularities of the process of structural modification of highly dispersed powders of saponite-containing material after mechanical dispersion have been studied. As information criteria characterizing the restructuring of the crystal lattice of minerals, changes are used that occur with the specific surface of powders at different grinding times and the exothermic thermal effect (enthalpy change) in the temperature range of 810 – 820 °С. It has been determined that during mechanical grinding of a saponite-containing material for more than 20 minutes, intensive modification of saponite occurs, associated with its structural changes, leading to the formation of serpentine. It has been established that the traditionally used criterion for evaluating the process of mechanical grinding of raw materials by the specific surface of the powder in this case is not a sufficient information parameter when optimizing structural changes in experimental samples. The dominant parameter of this process is the enthalpy factor, which characterizes the thermal effect of the structural modification.