Iron Ore Pelletization: Part III. Organic Binders

ABSTRACT This part reviews the goals of introducing organic binders into iron ore pelletization. Organic binders present a relatively small number of unique binding options but provide an extraordinary amount of flexibility in how to apply them. The key factors that lead into an effective organic binder are good dispersion into the iron ore, the ability to maintain the dispersion of the iron ore during the binding process, and limited water retention. The factors leading into a useful organic binder are more complex, depending on the availability of the material locally and the downsides it may introduce in the form of impurities (e.g. in some cases sulfur, phosphorous) or from poor quality control, especially for waste materials. Organic binders are primarily important because they do not typically introduce silica into the pellet, they are effective at lower overall weight dosages, and are more readily available in some locations than high-quality bentonite binders. A significant amount of emphasis is placed on the impact of organic binders on pellet strength, as the typically low dosages and the combustion of organic binders during firing means that most other pellet properties that would be negatively impacted by the presence of a binder are non-issues. Controlling dustiness among pellets formed with organic binders is also a major concern with several novel methods explored in recent years.