center of gravity of the total system so that the latter is induced to perform translatory vibrations whose direction is the same as the direction of the resulting vibration generating force under the influence of the vibration generating forces material components fed into the system are enduced to move in a manner which effects upward migration of the sand and activated coke particles on the inside surface of the tubular material carrier migrating particles of the bottom layer finally cause surface particles to slide back so that the material performs a continuous revolving motion in the direction of arrow moreover thorough mixing of several material components is achieved by causing the forces to act directly on the individual material particles so that they perform a relative mixing motion in addition to the revolving motion because of friction and particle surface serration as well as different particle inertia these phenomena combine to cause an ascension of the activated coke 13 across the specifically heavier sand 12 on the inclined surface of the mixture stream in the material carrier this permits good degassing of the coke particles 13 which are moving freely for a short period the activated coke particles 14 which are sliding down along the material surface are drawn again into the sand at re entry 15.