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The reduction kinetics of hematite in the presence of coke as a reductant was studied via isothermal and non-isothermal thermodynamic analyses. The isothermal reduction of hematite was conducted at a pre-determined temperature ranging from 1423 to 1573 K. The results indicated that a higher reduction temperature led to an increased reduction degree and an increased reduction rate. The non-isothermal reduction of hematite was carried out from room temperature to 1573 K at various heating rates from 5 to 15 K·min~(-1). A greater heating rate gave a greater reduction rate but decreased reduction degree. With an increase in temperature, both the reduction rate and the reduction degree increased at a smaller rate when the temperature was less than 1150 K, and they increased at a higher rate when the temperature was greater than 1150 K before completion of the reduction reaction. Both the isothermal and the non-isothermal reduction behaviors of hematite were described by the Avrami–Erofeev model. For the isothermal reduction, the apparent activation energy and pre-exponential factor were 171.25 kJ ·mol~(-1) and 1.80 × 10~5 min~(-1), respectively. In the case of non-isothermal reduction, however, the apparent activation energy and pre-exponential factor were correlated with the heating rate.
The reduction kinetics of hematite in the presence of coke as a reductant was studied via isothermal and non-isothermal thermodynamic analyzes. The isothermal reduction of hematite was conducted at a pre-determined temperature ranging from 1423 to 1573 K. The results indicated that a higher The non-isothermal reduction of hematite was carried out from room temperature to 1573 K at various heating rates from 5 to 15 K · min -1. A greater heating With an increase in temperature, both the reduction rate and the reduction degree increased at a smaller rate when the temperature was less than 1150 K, and they increased at a higher rate when the temperature was greater than 1150 K before completion of the reduction reaction. Both the isothermal and the non-isothermal reduction behaviors of hematite were described by the Avrami-Erofee v model. For the isothermal reduction, the apparent activation energy and pre-exponential factor were 171.25 kJ · mol -1 and 1.80 × 10 -5 min -1, respectively. In the case of non-isothermal reduction , however, the apparent activation energy and pre-exponential factor were correlated with the heating rate.