Reduction Kinetics of Fine Hematite Ore Particles in Suspension

Reduction Kinetics of Fine Hematite Ore Particles in Suspension

Chen, Z. (TU Delft (OLD) MSE-3; Flemish Institute for Technological Research)
Zeilstra, Christiaan (Tata Steel Europe Limited)
van der Stel, Jan (Tata Steel Europe Limited)
Sietsma, J. (TU Delft Team Kevin Rossi)
Yang, Y. (TU Delft Team Yongxiang Yang)

2021

Suspension reduction kinetics of hematite ore particles at 1710 K to 1785 K was described by the Johnson-Mehl-Avrami-Kolmogorov model with Avrami exponent of 1.405. The apparent activation energy is 105.5 kJ mol⁻¹ with the rate determining step of nucleation and growth. The reduction degree of the hematite at the endpoint is a linear function of temperature and the logarithmic oxygen potential of the reacting gas. A peak function of reaction rate constant with particle size has been verified in this work, and the maximum value of the reaction rate is located at around 85 µm particle size. The influence of heat transfer on the reaction process has been evaluated. The results suggest that the heating-up process for large particles, 244 µm particles, for instance, cannot be ignored. It can retard the reaction rate compared to small particles. Normally, the reaction rate constant decreases linearly with the increase of ln[p(O₂)] of the reacting gas mixture. However, 95 vol pct CO₂ in the reacting gas can accelerate the reaction rate of thermal decomposition of hematite due to the emissivity of CO₂ gas. It results in a higher reaction rate of 110 µm particles in 95 vol pct CO₂-containing gas than that in other less CO₂-containing gases.

http://resolver.tudelft.nl/uuid:1487b2c7-b877-405c-a28c-d62d44a2ee99

https://doi.org/10.1007/s11663-021-02269-5

1073-5615

Metallurgical and Materials Transactions B - Process Metallurgy and Materials Processing Science, 52 (5), 3393-3402

Institutional Repository

journal article

© 2021 Z. Chen, Christiaan Zeilstra, Jan van der Stel, J. Sietsma, Y. Yang