It is widely believed that dust suppression is a solved problem, and many surfactants are sold as commercial dust suppressants. But, it was recently reported by industry personnel that the available dust suppressants were not effective for iron ore. It was therefore important to find out why wetting reagents were not effective for iron ore. Are there other reagents such as hygroscopic materials and binders which will be more effective? How can these dust suppressants be evaluated on a laboratory scale?

A novel laboratory method consisting of a specialized drop tower apparatus was developed for iron ore that, for the first time, produced a direct, quantitative measurement of ore dustiness. Using this apparatus, it was found that surfactants did not have an effect on total airborne dust quantities and particulate matter concentrations generated from iron ore. However, hygroscopic materials like calcium chloride, and magnesium chloride, reduced airborne dust by as much as 58% +/- 13%. Another, non-corrosive suppressant reduced particulate matter concentrations by as much as 86% +/- 5%.