Iron Ore Pelletization: Part II. Inorganic Binders

ABSTRACT

The addition of pellet binders often represents a compromise between the pellet grade and quality measures as strength, reducibility, and dustiness. Each inorganic compound present within the pellet plays a specific role in each aspect of creating a high-quality pellet. This review seeks to clarify the roles of both binders and coincidentally present inorganic compounds to highlight the interconnected nature of the pelletization process. The goals stemming from the final reduction process are drawn back through the pelletization process to present a clear rationale for why each material can be used to control the pellet quality. Major inorganic binders such as bentonite, colemanite, and lime are examined along with less commonly used alternatives. Each of these binders has specific interactions with common components of the pellet composition, including common ions in water chemistry such as calcium and magnesium. Additionally, major advances in understanding the formation of pellets utilizing inorganic binders are highlighted, such as differential scanning calorimetry to predict sintering heat requirements, roll-press mixing to improve the dispersion of clay binders, and cold bonding techniques as an alternative to sintering.

KEYWORDS:

• Pelletization
• clay binders
• induration efficiency
• differential scanning calorimetry
• cold bonding
• mineralogy

Acknowledgments

We would like to thank Benito Barbabela e Silva, J. Murilo Mourão, Laurindo de Salles Leal Filho, and Sandra Lucia de Moraes for providing very helpful discussion which helped to influence the content of this review. We would also like to thank Chad Stewart for his assistance with the differential scanning calorimetry project.

Disclosure statement

No potential conflict of interest was reported by the author(s).