Double-screw trough conveyor for mixing, dewatering and heating

摘要

Installation for mixing, dewatering and calcining a solids mixture, having a double-screw trough conveyor (1) with direct or indirect heating (6), two hopper bunkers (3) with discharge control devices located at the inlet end of the conveyor, and a product outlet (4). Because the byproduct feed materials typically have a 500 micron particle size, 20% moisture content, and a tendency to stick and cause blockages, the conveyor inlet section has a full scroll flight and an anti-bridging device. A unit with 1m initial mixing, 6m heating and 1m cooling zone operated at 160kg/h and a maximum superficial trough fill depth of 40 mm achieved a final temperature of 480 deg C after 57 minutes. Heating may be applied from a radiant source above trough, or indirectly through the bottom of the trough.