PROCESS FOR CALCIUM HYPOCHLORITE

摘要

AN IMPROVED PROCESS FOR CALCIUM HYPOCHLORITE A process for producing calcium hypochlorite comprises wetting lime with an aqueous slurry of fine basic calcium hypochlorite crystals in a mixing zone to form an aqueous lime slurry. The aqueous lime slurry is reacted with a calcium hypochlorite solution in a crystallizing zone to produce a slurry of basic calcium hypochlorite crystals. The slurry of basic calcium hypochlorite crystals is separated in a first separation means into a slurry of fine basic calcium hypochlorite crystals and a slurry of coarse basic calcium hypochlorite crystals. The slurry of fine basic calcium hypochlorite crystals is returned to said mixing zone. The slurry of coarse basic calcium hypochlorite is conveyed to a second separation means to separate coarse crystals of basic calcium hypochlorite from a calcium hypochlorite mother liquor. Coarse crystals of basic calcium hypochlorite are admixed with lime and an alkali metal hypochlorite in a third mixing zone to form a mixed alkali slurry. The mixed alkali slurry is reacted with chlorine to form a paste of calcium hypochlorite dihydrate which is separated into a cake of calcium hypochlorite dihydrate and a paste liquor. The paste liquor is fed to the crystallizing zone. The cake of calcium hypochlorite dihydrate is dried to produce granular calcium hypochlorite. The novel process of the present invention produces crystalline basic calcium hypochlorite slurries having high filtration rates. In addition, the process provides improved crystal growth control and effectively prevents excess nucleation in the crystallization of the basic calcium hypochlorite.