To extract a constituent of fluorescent substance other than rare earth compds. from a fluorescent substance.
A Ba0.9Eu0.1MgAl10O17 fluorescent substance is mixed with an aluminum fluoride reactant for 1hr by using a mortar (the reactant addition step). The resultant mixture is put in an alumina-made boat, which is then placed in an alumina-made core tube in a tubular atmospheric furnace. Nitrogen gas and hydrogen gas are introduced into the core tube, and the temp. of the mixture is elevated at a temp. rise rate of 400°C/hr by energizing an electric heater and is kept at 1,200°C for 2hr. Then, the mixture is cooled at a temp. fall rate of 200°C/hr to room temp. (the thermal reaction step). After the reaction step, the thermal reaction product of the mixture remains in the boat. Thus, after adding the reactant to a fluorescent substance, the resultant mixture is heated to give a thermal reaction product and a part of the product is subjected to extraction.
KITAMURA KOJI
SHIGETA TERUAKI
HORII SHIGERU
MATSUOKA TOMIZO
