TY - JOUR

T1 - Iron Ore Reduction by Hydrogen Using a Laboratory Scale Fluidized Bed Reactor

T2 - Kinetic Investigation—Experimental Setup and Method for Determination

AU - Spreitzer, Daniel

AU - Schenk, Johannes

N1 - Publisher Copyright: © 2019, The Author(s).

PY - 2019/7/24

Y1 - 2019/7/24

N2 - The reduction kinetics of hematite iron ore fines to metallic iron by hydrogen using a laboratory fluidized bed reactor were investigated in a temperature range between 873 K and 1073 K, by measuring the weight change of the sample portion during reduction. The fluidization conditions were checked regarding plausibility within the Grace diagram and the measured pressure drop across the material during experiments. The apparent activation energy of the reduction was determined against the degree of reduction and varied along an estimated two-peak curve between 11 and 55 kJ mol−1. Conventional kinetic analysis for the reduction of FeO to metallic iron, using typical models to describe gas–solid reactions, does not show results with high accuracy. Multistep kinetic analysis, using the Johnson–Mehl–Avrami model, shows that the initial stage of reduction from Fe2O3 to Fe3O4, and partly to FeO, is controlled by diffusion and chemical reaction, depending on the temperature. Further reduction can be described by a combination of nucleation and chemical reaction, whereby the influence of nucleation increases with an increasing reduction temperature. The results of the kinetical analysis were linked to the shape of the curve from apparent activation energy against the degree of reduction.

AB - The reduction kinetics of hematite iron ore fines to metallic iron by hydrogen using a laboratory fluidized bed reactor were investigated in a temperature range between 873 K and 1073 K, by measuring the weight change of the sample portion during reduction. The fluidization conditions were checked regarding plausibility within the Grace diagram and the measured pressure drop across the material during experiments. The apparent activation energy of the reduction was determined against the degree of reduction and varied along an estimated two-peak curve between 11 and 55 kJ mol−1. Conventional kinetic analysis for the reduction of FeO to metallic iron, using typical models to describe gas–solid reactions, does not show results with high accuracy. Multistep kinetic analysis, using the Johnson–Mehl–Avrami model, shows that the initial stage of reduction from Fe2O3 to Fe3O4, and partly to FeO, is controlled by diffusion and chemical reaction, depending on the temperature. Further reduction can be described by a combination of nucleation and chemical reaction, whereby the influence of nucleation increases with an increasing reduction temperature. The results of the kinetical analysis were linked to the shape of the curve from apparent activation energy against the degree of reduction.

UR - http://www.scopus.com/inward/record.url?scp=85069686534&partnerID=8YFLogxK

U2 - 10.1007/s11663-019-01650-9

DO - 10.1007/s11663-019-01650-9

M3 - Article

AN - SCOPUS:85069686534

VL - 50.2019

SP - 2471

EP - 2484

JO - Metallurgical and materials transactions. B, Process metallurgy and materials processing science

JF - Metallurgical and materials transactions. B, Process metallurgy and materials processing science

SN - 1073-5615

IS - 5

ER -