TY JOUR TI ESTIMATION OF THE EFFICIENCY OF MECHANICAL ACTIVATION OF SILICA-CONTAINING ROCKS KW mechanical activation KW surface tension KW surface activity KW free surface energy KW specific surface area KW silica-containing raw material KW quartz sand JO Bulletin of Belgorod State Technological University named after. V. G. Shukhov AU Shamanina, A.V. AU Ayzenshtadt, A.M. AU Kononova, V.M. AU Danilov, V.E. PY 2021 IS 6 PB Belgorod State Technological University named after V.G. Shukhov