The invention describes a process of controlled comminution of a particulate solid material into a milling having particles of predetermined dimensions, and also a milling whirl chamber (B, C, D, E, F, H, G, I) having two end fac es (3 and 4) and a cylindrical side wall (5) with at least one nozzle (7) for injection of a working fluid into the chamber, means for introducing the particulate solid material into the chamber (8), a central axial passage (9) for discharge of the comminuted material in a flow of the working fluid from the chamber, and one or more mechanical elements (13, 15, 17, 19, 24, 28, 29 ) for control of the comminution process in the chamber. The process includes tangentially injecting the working fluid into the chamber, introducing the particulate solid material for creating in the chamber a vortex where the particulate material undergoes comminution in the flow of the working fluid, and controlling uniformity of the milling and dimensions of the particles therein by deliberately accele
