MECHANOCHEMICAL ASPECTS OF COMMINUTION TH EORY

A system dealing with the mechanical dispersion of solids is presented ; knowledge is based on the author's research and experimentation, don e in the last decades. Phenomena are interpreted mainly in terms of so lid state physics and are only loosely connected to colloid chemistry. The approach of research was, however, purely colloid chemical, thus this work can be considered as a continuation of Professor Buzagh's sc ientific activity. The crystal structure of crystalline solids is dras tically changed by intensive mechanical forces: permanent lattice defe cts, polymorphic transformations, total amorphisation, homogeneous che mical reactions may occur and a definite increase of surface free ener gy can be observed; all these phenomena show that a high share of grin ding energy can be permanently stored in the ground material. Due to t his mechanical activation the solid will be capable of surface and sol id-state reactions, and consequently the dispersity of the system is d ecreased irreversibly and both the phase composition and chemical comp osition are changed in the direction of increased system stability. No vel type mechanochemical ''capillary'' reactions are described, too. R eactions and surface interactions can be modified to a certain extent by vapour adsorption. Thermal and adhesion properties of solids, expos ed to intensive grinding, and being in an active state or having been subjected to mechanochemical transformations are drastically changed a nd this change may influence several technologies involving grinding.