Production of metallic halogen phosphorus particles with defined grain size distribution with improved powder permeability

摘要

A method for preparing metal halide phosphor particles, e.g. barium- and/or strontium-containing halide phosphor particles, of a selected particle size range with improved powder flowability which method comprises the following steps : (1) firing the raw mixture materials of said phosphor to produce a sintered phosphor mass that is pulverized, (2) mixing said pulverized phosphor mass, optionally after one or more firings, in a liquid mainly containing a water-miscible organic solvent with an organic acid dissolved therein, said acid being capable of forming with metal contained in the phosphor a salt the solubility of which in water at 20 DEG C is less than 0.5 g per 100 ml, and (3) subjecting the thus treated phosphor particles in wet and/or in dry state to a separation treatment to collect phosphor particles having a grain size smaller than 40 mu m but larger than 2 mu m.