Determination of direct reduction kinetics of Menteş hematite ore in fluidized bed reactor

Within the scope of this study, the iron ore obtained from the Menteş region of Kayseri province was calcined. Afterwards the calcined ore was reduced at 800 ºC, 850 ºC and 900 ºC process temperatures in a laboratory scale fluidized bed reactor with gas mixtures containing various amounts of CO and/or H2 at flow rate of 6 times the minimum fluidization velocity. The instantaneous conversion of the ore during the experiments was calculated from the gas analyzer data, which simultaneously recorded the composition of the flue gas leaving the reactor. On the other hand, the final reduction and metallization degrees of the ore at the end of the experiment were determined by chemical analysis and compared with the final values calculated by gas analysis, and the results obtained by both methods were found to be compatible. Within the scope of the study, full reduction and metallization was achieved in the samples reduced at 800 ºC and 850 ºC with the reducing gas mixture containing 25% CO, 25% H2, 50% N2. In other experiments, the degree of metallization varied between 62-100% in proportion to the amount of H2 in the reducing gas stream, and the lowest conversion values were recorded at 900 ºC for all gas compositions studied. The sintering caused by high temperature was effective in the emergence of this situation. In the last part of the study, it was determined that the reduction kinetics of Menteş iron ore with gas reactants under fluidized bed conditions fit the "Two Dimensional Diffusion, D2(α)" (g(α)=(1-α)ln(1-α)+α=ki.t) model. The calculated activation energy value of 19.73 kJ/mol also supported this finding.