Abstract: An impact rotor arranged concentrically to the axis of a drum has preferably four beating blades which are wave-shaped on the outer peripheral side.

Abstract: A method for regenerating foundry old sand which method combines impact and shearing stress of the sand grains which occurs with simultaneous dust removal. The dust removed by suction contains non-burned bentonite and carbon parts which can be re-used in the same way as the regenerated material of core sand. Environmental pollution and quantities for dumping are drastically reduced.

Abstract: The clay-bonded used casting sand is treated in a drum rotated about a horizontal axis by continuously feeding a sand additive to the drum in an amount sufficient to maintain the quantity of sand in the drum at about 26-40 percent by volume of the drum to compensate for the amount of shell material drawn off by pneumatic dust removal devices so as to maintain an optimal relationship between the volume of the drum in the quantity of sand in the drum over the entire period of treatment. The amount of sand fed to the drum may be controlled by the amount of current consumed by a motor used for rotating the drum.

Abstract: Arranged in the upper region of a drum which rotates about an axis there is a dust box for dust removal. The box is connected with a line, which leads outwards, by way of a laterally arranged discharge channel. Arranged between the dust box and a baffle rotor which rotates about the axis are baffle areas which form labyrinth-like passages for the dust to the dust suction openings in the dust box.

Abstract: Regeneration of clay-bonded used foundry sand for reuse instead of new sand. A dry mass of used sand is rubbed for such a length of time, is accelerated suddenly and delayed, and is freed continuously of fine components, until the fine matter, active bonding clay and oolitization degree fall below certain threshold values such that the regenerated product substantially gains the characteristics of new sand. An apparatus for regeneration treatment contains a horizontal revolving sand drum (10), an impact rotor (30) disposed inside said drum in the area of the fall stream (46) of the used sand and a pneumatic dust removal device (36) disposed in the inside of the drum. A chemical secondary treatment of the regenerated product can be carried out advantageously in the same installation in order to bind remaining fine matter to the surface of the grains of sand and simultaneously to seal the pores of the grains.