GB1445330A - Process for forming particles - Google Patents

Abstract

1445330 Mills; comminuting fertilizers FISONS Ltd 26 July 1973 [3 Aug 1972] 36210/ 72 Heading B2A {Also in Division B5] A process for forming material into particles e.g. by agglomeration, comprises classifying the particles according to size, feeding those particles having a size above or below that desired to a storage member, controlling the rate of removal of the particles from the storage member and recycling the removed particles to the particle forming device. As shown in the Figure, the apparatus comprises a rotary drum granulator 1, a rotating drum drier 2 and a rotating drum cooler 3 from which the granular product is raised by elevator 4 to a vibrating screen classifier 5. Oversize particles are fed via a crusher 6 to a storage hopper 7 and undersize particles are fed via a chute also to hopper 7, particles of the desired size range being passed on for further treatment. Particles from hopper 7 are fed onto a belt weigher 8 which monitors the rate of particle flow thereon by regulating the hopper outlet area, and thence via belt 9 and elevator 10 to the granulator 1. The means removing material from hopper 7 may alternatively be a vibrating extractor or screw or a conveyor belt having means ensuring a uniform load thereon e.g. a doctor blade, means regulating the hopper orifice or means regulating the conveyor speed. Fresh raw material is fed from hoppers A, B or C or as liquids, directly into granulator 1. The particle-forming apparatus may alternatively be prilling or spheroidising apparatus. The material may be a fertiliser formulation e.g. of mono-ammonium phosphate, potassium chloride, and aqueous ammonium nitrate.