Journal Article

The Effect of the Endothermic Reaction Nature on the Iron Ore Pellet Reduction Using Hydrogen

Du, Sichen, Fogelström, Julia Brännberg, Hessling, Oscar, Kojola Niklas

2022

Overview

A novel experimental setup for simultaneous weight, surface temperature, and center temperature tracking of a single iron ore pellet under reducing conditions has been utilized. Studies conducted in the setup indicate that the reduction of iron ore pellets in a pure hydrogen atmosphere is controlled by several transport steps inside the pellet. It is further shown that for a period of time during reduction, the reduction rate is limited by the heat transfer inside the sample. Any attempt to make accurate and robust models of the hydrogen based iron ore reduction process must therefore consider heat transfer in the pellet. The reduction is observed to take place in a reduction zone extending along the pellet radius, consisting of a mix of different phases. The amount of the different phases varies with radial position and time, as does the observed temperature gradient between the surface and the center of the pellet. Representative literature data on actual transfer coefficients of this system is therefore not available. Apparent thermal conductivities for the different experimental temperatures are evaluated based on the experimental data and found to be significantly lower than the corresponding value for dense iron.

• Publisher: Springer Nature B.V
• Subject: Atmospheric models / Endothermic reactions / Heat transfer / Hydrogen reduction / Iron compounds / Iron ores / Pellets / Reduction / Temperature