METHOD AND APPARATUS FOR GRANULATION

摘要

A method of melt granulation for powdery material is disclosed wherein the powdery material is discharged onto the upper surface of a heated rotary spreader (10) for migration under centrifugal force to the periphery of the spreader accompanying by melting of a portion of the material and enrobing of non-melted particles by the melted material for discharge as enlarged granules from the periphery of the spreader. To improve the quality of the granules produced, the feed material is supplied to the spreader at two separate locations. The first location is the central position (10a) of the spreader to provide the melted material and the second location is adjacent to the periphery (10c) of the spreader. The spreader is preferably in the form of a concave bowl or inverted truncated cone or dish. Feed material is supplied to the first location by a screw feeder (30) extending down the side of the dish and at the second location by a rotary vaned distributor (50) locatated within the dish which radially flings the feed material onto the inclined dish wall. The process and apparatus is particularly useful for the production of non-sticky granules which are difficult to form when a single central feed of material is used.