TREATMENT OF MOLTEN BLAST FURNACE SLAG AND TREATING APPARATUS

PROBLEM TO BE SOLVED: To provide a treating method of a blast furnace slag which can separately produce crystallized slag grains or glassy slag grains from the molten blast furnace slag with an one apparatus. SOLUTION: In the treating method for producing the slag grains with a blasting granulation from the molten blast furnace slag, gas is blasted to the flowing down molten blast furnace slag at the inlet in an outer cooling rotary cylinder 1 to form the slag as granular drips. The granular drips are brought into contact with the inner surface of the rotary cylinder 1 and rapidly cooled to the temp. in the range from the re-fusion limit temp. or lower to the crystallizing lower limit temp. or higher at the vitrified cooling speed or more and discharged from the outer cooling rotary cylinder 1. In the case of producing the crystallized slag grains, the high temp. slag grains discharged from the outer cooling rotary cylinder 1 are slowly cooled, and in the case of producing the glassy slag grains, the high temp. slag grains discharged from the outer cooling rotary cylinder 1 are further rapidly cooled to the crystallized lower limit temp. or lower at the vitrified cooling speed by blasting the gas with a cooling speed adjusting gas blasting means 3 at the outlet of the outer cooling rotary cylinder 1.