The mining industry seeks innovative and sustainable solutions for its production processes in the face of the international macroeconomic scenario. The Brazilian iron mining industry is among the largest in the world, with iron ore being one of its main export products.

The majority of Brazilian iron ore is found in the Alegria Complex, located in the state of Minas Gerais, Brazil. The geological context of this region includes the presence of friable itabirite formations. At greater depths, where weathering processes are typically less active, iron ore bodies tend to have lower iron content and higher hardness/compactness.

The use of iron ores with lower iron content and higher compactness, responsible for generating more waste during beneficiation, is occurring at a time when mining must develop technologies to reduce its environmental impact. As an alternative to depositing waste in dams, the sandy material can be filtered and stacked. However, the ultrafine portion (slimes) of the waste, which is rich in iron and not efficiently filtered through vacuum processes, possesses challenges and opportunities.

This study evaluated the effectiveness of adding different percentages of ultrafine iron ore (slimes) in the pelletization process as an alternative to its disposal as waste. The ultrafines are obtained during the ore beneficiation process, and their reuse was aimed primarily at metallurgical recovery during beneficiation, as they can contain up to 48% iron in their composition. The results of this alternative use is reduction in its potential as an environmental liability and the reutilization of this waste, promoting a more sustainable mining production by significantly contributing to the management of non-renewable resources. Additionally, this initiative makes the segment more competitive by utilizing low-cost raw materials.

The results of this study evaluates iron ore pellets produced from pellet feed incorporating high-specific-surface material, the ultrafine portion. Samarco’s pilot pelletizing plant conducted tests to assess the chemical, physical, metallurgical quality, and microstructural phase formation in pellets produced from different levels of specific surface area in the pellet feed. Degradation during handling tests of the pellets were also performed, considering resistance to surface and volumetric fragmentation due to impact. The results show the ideal process constraints for specific surface, loss on ignition, incorporation content of ultrafines, and chemical quality for pellet production within the highest standards of excellence historically practiced by Samarco, with significant gains in impact resistance and decrease of degradation during handling of the pellets.