The presence of anywhere from 1% to 10% of sulfur in the pulverized coal burnt by electric power generation plants, produces in the flue gas high concentrations of sulfur dioxide (SO2), a gas which if left untreated in the atmosphere, produces acid rain. Flue gas desulfurization (FGD) using powderized trona (sodium sesquicarbonate), in dry sorbent desulfurization systems, has gained widespread acceptance. Trona reacts with SO2 to produce dry reaction products that are then removed either in dust collectors or electrostatic dust precipitators (ESP). The reaction efficiency depends upon, among other factors, the particle size distribution of the trona being reacted.
Hosokawa produces complete trona grinding systems using air classifying mills, which are being successfully used with proven effectiveness around the world.