Non-isothermal reduction kinetics of high-aluminium iron ore pellets

There are two aspects containing in the non-isothermal reduction process in the shaft furnace. One is the surrounding gas temperature of the pellets changing with time and the other is the graded distribution of the internal temperature of the pellets. The reduction of the pellets in the shaft furnace will be regarded as the non-isothermal reduction formed by the constant temperature process of different temperatures. Results show that when the surrounding gas temperature of the pellets with time is a linear relation, the relation of the pellets temperature and time can be expressed as Tpellets = 0.10233τ + 219.7(K),and the experimental result of the change of the reduction degree with time is almost in complete agreement with the calculated result. When the surrounding gas temperature of the pellets with time is a nonlinear relation, the relation of the pellets temperature and time can be expressed as Tpellets = -6 × 10-21 τ 6 + 3 × 10-16 τ 5 - 6 × 10-12 τ 4 + 6×10-8 τ 3 and the temperatures of the gas - 0.0003τ2 + 0.6783 τ + 348.956 (K) phase and the solid phase are basically parallel in the most region of the shaft furnace.