Producing crystallisation seeding material for water purificn. - by precipitating insoluble calcium salts or phosphate(s) in fluidised bed reactor using particles discharged from reactor after crushing

摘要

The method is intended for producing seeding material to act as crystallisation nuclei for the pptn. of insoluble calcium salts in a fluidised bed reactor used for water purificn.. This material is produced by crushing (9,10) at least a proportion of the particulate ppte discharged from the reactor, pref. after drying (4) this ppte.. The crushed material is pref. screened (11) to produce one or more fractions between 0.1 and 0.6mm particle size. The sharp irregular calcium carbonate particles thus produced may be used as seed material in a fluidised bed water softening reactor into which water and alkali are separately fed. Alternatively such particles of calcium carbonate or phosphate may be similarly used to ppte calcium phosphate in effluent water.