Method and apparatus for treating a layer of bulk material

An apparatus for cooling hot bulk material using a cooling gas at a temperature lower than a temperature of the hot bulk material, comprising:

• a grate comprising a plurality of separately driven adjacent planks which are elongate in the conveying direction, the grate being configured to convey a layer of the hot bulk material lying on the grate from a feed end of the apparatus toward a delivery end of the apparatus in a conveying direction and through which the cooling gas flows, the grate further comprising material-holding recesses on the surface of the grate which include air passage openings and being configured so that there is no vertical mixing movement in the layer of hot bulk material as the layer of hot bulk material is conveyed by the grate,
• a conveyance passage configured to convey the cooling gas into the apparatus so that the cooling gas passes from an underside of the grate to an upper side of the grate through the air passage openings and through the layer of hot bulk material on the grate,
• a drive moving the planks forward and backward in an advancing stroke and a return stroke in the conveying direction and controlling the motion of the planks in such a way that the return strokes of adjacent planks take place non-simultaneously and the advancing strokes of adjacent planks take place simultaneously,
• wherein the grate is configured to deliver the layer of hot bulk material at the delivery end of the apparatus.