Determination of the Optimum Granulometric Composition of Bentonite and Limestone in the Production of Pellets for Metallization

When assessing the quality of pellets for metallization (DR-grade) with varying bentonite and limestone particle sizes, it was found that regrinding bentonite and limestone beyond optimal values does not significantly improve the quality of green, dry, and fired pellets, and in some experiments, it leads to a deterioration in the rheological properties of bentonite. Increasing the content of –44 μm in limestone does not affect pellet quality. Traditional requirements for bentonite and limestone (in this case: –71 μm content in bentonite and limestone at 93 and 94%, respectively) for the production of pellets from finely ground concentrate (high enrichment, DR-grade, metallization) are optimal. The grinding requirements for bentonite and limestone for the production of blast furnace pellets (BF-grade) and pellets for metallization (DR-grade) are identical. The optimal balance is considered to be between the maximum achievable pellet strength and the minimum costs of grinding additives.