Thermal comminution is an industrial process specially suited to very abrasive material, when contamination with Fe from wearing parts of conventional crushing and grinding equipment must be avoided. It involves an initial step of heating the material to be comminuted, followed by sudden cooling (quenching) and finally by a conventional mechanical process to disassemble the particle aggregates. The thermal step is, in fact, a pre-fracturing process. The heating operation causes changes in phase of the minerals and changes in volume of these minerals and other substances included in pores and cracks. The cooling operation causes thermal shock reversions or the phase transformation and consequent generation of internal stresses, high enough to fracture the solid.