PURPOSE: To improve fluidity of mortar and concrete not fixed yet by spraying fine powder of square slag having an average particle diameter of ≤ a specific value upon a burner flame, heating and sphering.
CONSTITUTION: Slag discharged from blast furnace, converter, etc., or powdered by a proper method or granulated slag is further pulverized by using a roller mill, etc., and adjusted to ≤ about 100μm average particle diameter by using a classifier, etc. After the operation, the slag has 6,000-10,000cm2/g specific surface area. In order to sphere the slag, the fine powder of slag is fed to an air-supplying pipe, sprayed upon a burner frame at ≥1,380°C and heated, fused and sphered by surface tension. In the operation, the temperature of the burner should be 50-100°C higher than the melt temperature of the slag. A thinning pipe having a cross-sectional area of 1/10 to 1/40 cross-sectional area of the air-supplying pipe is arranged in the air-supplying pipe at a part at which a feed pipe for the fine powder of the raw material slag opens and transported air is jetted at 150-300m/second.
SHIROUCHI AKIJI
KUWAMOTO HIDEYOSHI
