To provide a solid slag of high strength and high quality.
In a slag cooling tower 10, a temperature of an upper part 53 of a fluid bed is determined to be higher than that of a lower region 52 of the fluid bed. A cooling speed of the molten slag is lowered by reducing the temperature difference between the upper part 53 of the fluid bed and the molten slag introduced to the upper part 53 of the fluid bed, and the solid slag cooled by some degree at the upper part 53 of the fluid bed, can be discharged after being further cooled at the lower part 52 of the fluid bed. Whereby the slag can be sufficiently cooled while sufficiently lowering the cooling speed of the molten slag in comparison with a case when the temperature of the fluid bed is approximately unified in the height direction.
MATSUMOTO KENJI
Shiro Terasaki
Yoshiki Kuroki