(211d) Direct FeCO3 Reduction with H2

Loder, A., Graz University of Technology
Lux, S., Graz University of Technology
Siebenhofer, M., Graz University of Technology
The iron- and steel industry has a huge potential for reduction of CO2 emissions [1]. Direct reduction of siderite ore (FeCO3) to elemental iron may make use of H2, cutting down CO2 emissions by up to 60 %.

Direct FeCO3 reduction with H2 was investigated in terms of FeCO3 conversion and the amount of elemental Fe in the solid product. Five factors were tested for their influence on the reduction of a FeCO3-ore from the Erzberg in Austria: process temperature, particle size, initial mass of the ore, gas flow and hydrogen concentration. The reaction kinetics were investigated with models from Khawam and Flanagan [2].

The investigation of direct FeCO3 reduction with hydrogen was based on Design of Experiments. The factors process temperature, particle size, gas flow and the interaction of gas flow*temperature and gas flow*gas flow were identified as strong impact on FeCO3 conversion. The sigmoidal curve of the A4 model (Avrami-Erofeyev) [2] represents the experimental data of FeCO3 conversion vs. time best. The limiting effect of the temperature on maximum FeCO3 conversion was included in the model.

The information on the process parameters and the reaction rate law is needed for process and plant design for direct FeCO3 reduction with H2.

[1] M. A. Quader, S. Ahmed, R. A. R. Ghazilla, S. Ahmed, and M. Dahari, “A comprehensive review on energy efficient CO2 breakthrough technologies for sustainable green iron and steel manufacturing,” Renew. Sustain. Energy Rev., vol. 50, pp. 594–614, 2015.

[2] A. Khawam and R. D. Flanagan, “Solid-State kinetic Models: Basic and Mathematical Fundamentals,” J.Phys.Chem.B, vol. 110, no. 35, pp. 17315–17328, 2006.