Structural Modification of Fine Powders of Overburden Rocks of Saponite-Containing Bentonite Clay

Abstract—The kinetic regularities of the process of structural modification of highly dispersed powders of a saponite-containing material after mechanical dispersion are studied. Changes in the specific surface of the powders at different grinding times and exothermic thermal effects (changes in enthalpy) in a temperature range of 810–820°C are used as information criteria characterizing the rearrangements of the crystal lattice of the minerals. It is determined that, in the case of mechanical grinding of a saponite-containing material for more than 20 min, its structural changes leading to the formation of serpentine occur intensely. It is found that, in this case, the traditionally used criterion for evaluating the process of mechanical grinding of raw materials by the specific surface of the powder is not a sufficient information parameter when optimizing the structural changes in experimental specimens. The predominant parameter of this process is the enthalpy factor that characterizes the thermal effect of the structural modification.