Spray graining technique for preparing granular hydrated alkali metal dihaloisocyanurate

摘要

Granular alkali metal dihaloisocyanurate particles (such as sodium dichloroisocyanurate) comprised of a core of alkali metal dihaloisocyanurate encapsulated in a plurality of layers of hydrated alkali metal dihaloisocyanurate are produced by spraying a pumpable and sprayable aqueous slurry of hydrated alkali metal dihaloisocyanurate particles onto suspended particles of solid alkali metal dihaloisocyanurate in anhydrous or hydrated form above a moving bed of said particles. The solid particles coated with the slurry are heated to simultaneously evaporate and remove water from the slurry whereby said particles are coated with a layer of solid hydrated alkali metal dihaloisocyanurate.PPA portion of the moving bed of coated particles is removed from the spraying zone and further processed, if desired. In one embodiment, the hydrated particles are sized, and undersize and crushed oversize are recycled to the moving bed. In another embodiment, the coated particles, with or without sizing, are dried to produce granular particles having the desired moisture content or degree of hydration.PPThe resulting coated or layered granular particles of hydrated alkali metal dihaloisocyanurate have a high level of integrity and resist degradation and dusting when subjected to rather severe handling conditions. In addition, the novel granular hydrated alkali metal dihaloisocyanurate particles of this invention are highly stable when contacted with lighted cigarettes, organic materials and the like.