To effectively utilize the residual NOx removing performance of a used NOx removal catalyst.
The used NOx removal catalyst 2 used in an NOx removal equipment 1 and discharged is washed in a washing tank 3 and pulverized with a pulverizer 4. The pulverized NOx removal catalyst 2a is blown into waste gas 6 discharged from a melting furnace 5 in a temperature range in which the catalyst is active. The pulverized NOx removal catalyst 2a blown into the waste gas 6 and reutilized is collected in a dust collector 7, sent to the melting furnace 5 and melted to form slag 11. Since the used NOx removal catalyst 2 is pulverized, catalyst parts having NOx removing performance are exposed to the surface and NOx in the waste gas 6 is decomposed by this catalyst surface.
MORI TAKASHI
YAJIMA SHIRO