(388ag) Increasing the Clay Content and Size of Iron Ore Pellets Reduces Their ‘Dustiness'

Potentially hazardous dust is generated when making, handling, and shipping iron ore pellets. Fugitive dust is considered a surrogate for hazardous air pollutants such as Pb, Hg, and incomplete combustion products, and may be a health concern in its own right. Dust generation may depend on many factors, such as the size of iron ore pellets and their microstructure (which is influenced by binders). To test this hypothesis, iron ore pellets were made in the laboratory from an un-fluxed, magnetite concentrate at various sizes and using bentonite clay as a binder. Pellets were made at various sizes ranging from 6.3 – 12.7 mm in diameter, with bentonite clay doses ranging from 0 – 8.9 kg/t, and tested on MTU’s dust tower. Pellet dustiness ranged from 10 to 100 mg dust per kg pellets, similar to levels observed in industry-made pellets. Pellet dustiness decreased with increasing pellet size and bentonite clay content.