| 摘要 |
PURPOSE:To manufacture easily the oxysulfide of a rare earth element with high purity and little ununiformity in quality by reacting the hydroxide of the rare earth element with sulfuric acid or a sulfate and by heating the reaction product in an atmosphere contg. gaseous hydrogen. CONSTITUTION:A slurry of one or more kinds of hydroxides of rate earth elements prepd. by adding an alkali to an aqueous soln. of the oxides or the like of the rare earth elements is reacted with sulfuric acid or a sulfate such as magnesium sulfate in water preferably under heating. The reaction product is optionally roasted at about 600-1,200 deg.C in an oxidizing atmosphere such as the air, and it is roasted at about 600-1,200 deg.C for about 1-5hr in an atmosphere of gaseous hydrogen or a gaseous mixture of gaseous hydrogen with an inert gas. The oxysulfide of a rare earth element of high quality can be obtd. in a high yield. The oxysulfide is used as a superior base material for a fluorescent substance.
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