The fluid bed cooler cools down the molding sand which is conveyed from a crusher through an upstream magnetic drum into the cooler. The machine (Fig. 1, Jöst GmbH & Co. KG) is not vibrating but stationary. The sand is fluidized by means of a special fluidization plate by a powerful vertical air flow. It then has flow characteristics like water. When fluidized, the heat is released via contact heat exchange to a tube matrix with high surface passed by water. As positive side effect light organic binder particles are discharged via air flow and the L.O.I. of the reclaimed sand is reduced.