| Title |
Characteristics of the Hot Fluidized Bed for Iron Ore Fine in a Wide Size Range |
| Authors |
정우창(Uoo Chang Chung) ; 이일옥(Il Ock Lee) ; 주상훈(Sang Hoon Joo) ; 정원섭(Woo Sub Chung) ; 정원배(Won Bae Chung) |
| Abstract |
Currently more than 80 % of raw iron ore is produced in a state of fines under 8 ㎜ in diameter in the world. In order to produce metallic products such as DRI (Direct Reduced Iron) and/or hot metal directly from fine iron ore without pretreatment, a fluidized bed technology should be adopted. In the present study, characteristics of a fluidized bed with iron ore fines in the size range of 1 to 5 ㎜ have been investigated at high temperature (700-850℃) in terms of the minimum fluidization velocity, fluidization patterns, the pressure drop, the solid hold-up in the reactor, etc. using a laboratory scale fluidized bed reactor. It was observed that the minimum fluidization velocity of particles in wide size range is equivalent to that of the particle of harmonic mean size. The optimum gas velocity for fluidization is about 1.2 to 1.3 times of the minimum fluidization velocity and this is similar to the result observed in the experiments in cold (room temperature) state. During heat-up and reduction in the reactor, iron ore particles are degraded due to the thermal and reduction reaction shocks. It was also found that the degradation of ore particles was completed in the early stage of reduction reactions, within 10 minutes. |