PELLET EXCELLENT IN PROPERTY TO BE REDUCED AND ITS MANUFACTURE

摘要

PURPOSE:To manufacture a pellet free from the generation of a reduction retarding phenomenon by specifying the length in the diametral direction of a pellet to form a blast furnace charging raw material. CONSTITUTION:Iron ore, generated powder from one's own factory, limestone, dolomite, serpentine, etc., are quantitatively quarried from raw material tanks 1 to 4, are mixed with water and kneaded in a mixing tank 7 and are charged to a compression extruder 11 via a hopper 9 to form a columnar raw pellet 12 having about 6 to 7mm diameter and about 6 to 21mm length by 3 to 3.5kgf/ cm2 pressure. This raw pellet 12 is sieved by a screen 14, among which the one having about 5 to 15mm grain size is fed to housing 18 and is dried at 220 to 270 deg.C in a drying chamber to evaporate stuck water. Then, the pellet is preheated at 1000 to 1150 deg.C in a preheating chamber, is thereafter fired at 1250 to 1280 deg.C in a firing chamber and is cooled to a room temp. in a cooling chamber to manufacture a pellet 19 having =6mm length in the diametral direction. In this way, the pellet 19 free from the generation of a reduction retarding phenomenon can be obtd.