Iron ore pellet drying assisted by microwave: A kinetic evaluation

ABSTRACT

Drying is a critical process step to achieve excellent pellet quality in pelletizing process. The complexity and energy consumption toward moisture removing, especially for highly hydrated iron ore, increased the need for breakthrough enhancements to this process. The present study has evaluated kinetics parameters of the moisture release from iron ore green pellet using energy transmitted through microwave (frequency of 2.45 GHz). The influence of pellet size and output power on the moisture effective diffusivity (D_eff) and the drying activation energy (E_a) were evaluated. The results make possible to compare the cutting-edge approach with traditional convective drying. Pellet physical quality was investigated through the green crushing strength (GCS), which shows smooth reduction in earlier stages, however not affecting the final dry GCS results. Bonded hematite reduction and calcination of goethite was identified at the microstructure through reflected light microscopy, SEM showed micro cracks formation in several grains.

KEYWORDS:

• Pelletization
• drying
• iron ore
• microwave

Acknowledgment

The authors would like to thank Samarco Mining, CAPES-PROEX, CNPq and FAPEMIG for stimulating and supporting research.

Disclosure statement

The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the article.