X-ray microtomography for sequential imaging and analysis of iron ore pellets under reduction

This work has been a part of the development of a method where x-ray microtomography and image analysis are used to quantify the crack distribution and propagation in iron ore pellets during reduction.Reduction experiments on 7 pellets, were performed in 4 steps during the transformation from hematite to magnetite at 500 °C. The pellet microstructure is imaged and visualized at each step using x-ray microtomography and the crack distribution characterized with image analysis.For the chosen pellet composition, networks of cracks are already visible in the unreduced state and show a successive growth during the first 30 minutes of reduction. As the transformation to magnetite is complete, crack growth has stopped and in several cases a partial regression is observed.It can be concluded that the use of X-ray microtomography has the potential to become an important tool for material characterization in iron ore pellet research due to its ability to gather information from the bulk of the material at several different stages of a process.Godkänd; 2012; 20120614 (ysko