This paper presents the results of research on mechanical activation of dry mica in an ultra centrifugal mill with a peripheral comminution path. The variable parameters of the mill operation were: rate of rotor revolution (no = 10.000 and no = 20.000 r.p.m.), circle sieve mesh (80, 120, 200 and 500 μm) and the current intensity. The following technological parameters were studied: mechanical activation time, rotor velocity, mill capacity and specific energy consumption. The mechanically activated powder was examined by application of thermal and thermogravimetric analyses, analysis of the degree of mechanical activation and the specific surface area, as well as X-ray diffraction analysis. The optimal results of the mechanical activation were obtained with a full mill load, using a circle sieve mesh of 80 μm and nominal rate of rotor revolution of 20.000 r.p.m. It was shown that the mechanically activated mica obtained employing these process parameters had passed into the amorphous state.

Keywords: Mica, Amorphous materials, Ceramics, Thermogravimetric analysis (TGA), Crystal structure.