| 摘要 |
PURPOSE:To perform the pre-reducing baking of a pellet in a high pre-reducing ratio at a relatively low temp., by successively performing drying, coking by thermal decomposition and hardening with respect to the pellet granulated by using a petroleum residue oil as a binder in a moving grate furnace. CONSTITUTION:In a moving grate furnace 2 consisting of a drying chamber 2A, a coking over 2B and a hardening chamber 2C, a powdery iron ore O is granulated by using a petroleum residue oil as a binder in a granulating apparatus 1 to form a pellet Pg which is, in turn, supplied to the above mentioned drying chamber 2A where the raw pellet Pg is dried at 200-350 deg.C by gas G1. Subsequently, the petroleum residue oil being the binder is thermally decomposed and coked at 550-650 deg.C by gas G2 in the coking oven 2B and the dried pellet is subjected to pre-reducing and further heated to 850-950 deg.C to promote reduction by the generated gas in the hardening chamber 2C while metal iron is formed on the surface of the pellet to obtain a high strength pre-reduced pellet Pc which is, in turn, supplied to a reducing furnace 3. |
