| 摘要 |
PURPOSE: To obtain particles each being spherical as a single particle not as aggregated particles and suitable as the source material of a phosphor for a fluorescent lamp by mixing an aq. phosphate soln. and an acid soln. of rare earth element under specified conditions of the liquid temp. of each source material, the mixing rate, and the precipitation. CONSTITUTION: (1) First, a phosphate soln. and an acid soln. of rare earth elements are mixed for precipitation. In this process, temps. of each source material soln. is preliminarily controlled to obtain 0-20 deg.C temp. of the mixture soln. (2) Then before the precipitation begins, mixing of the whole source material solns. is rapidly completed. (3) This mixture soln. is left M standing or heated to start precipitation, and heated to 60-100 deg.C final liquid temp. to terminate the precipitation. (4) The precipitate is filtered, washed with water and dried or calcined to obtain the particles of the purpose. These particles are crystalline single spherical particles of rare earth element phosphate particles with D50 value ranging 2 to 10μm in the distribution of the particle size.
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