PURPOSE: To prevent green ore briquets from mutual adhesion and increase the strength thereof in a short time period of curing by a method wherein the cold- briquetted ore such as iron ore is passed through a hot, humid atmosphere at a specified temperature.
CONSTITUTION: Portland cement is added to iron-containing powder material such as particulate iron ore, iron-containing dust, etc. in a weight ratio of 0.08W1, and the mixture is granulated into green pellets having a water content of 5% by a granulating machine with a granulating pressure of 2ton/cm2. The green ore pellets 17 are thrown into a shaft furnace 1 through a chute 14, and piled on the furnace bottom 5 provided with slanted surfaces 6. A mixture of hot air and steam for forming the hot, humid atmosphere having a temperature of not lower than 70°C and a water content of not lower than the saturation point is blown in from pipes 2, 8. Simultaneously, an ore-discharging turntable 9 below the bottom 5 is rotated and the ore pellets being discharged via gaps 7 are raked out by a scraper 12. In this case, the green pellets in the furnace are allowed to descend through the hot, humid atmosphere at a descending rate of not lower than 0.1m/hr, thereby maintaining the strength of the pellets while preventing them from mutual adhesion.
ICHIDATE MINORU
KUBO TOSHIHIKO
