SO{sub x} emissions in firing ceramics

Emissions of sulfur oxides as SO{sub 2} and SO{sub 3}, commonly called SO{sub x}, are regulated under the US Clean Air Act (CAA) as Criteria Pollutants. A regulatory focus has remained on power industry SO{sub x} emissions since passage of the CAA. Moreover, it has been recognized for years that noticeable SO{sub x} emissions also are generated during the firing of traditional ceramics produced from a few, but not all, raw materials. The consequences of these emissions have included scumming and efflorescence phenomena as well as corrosion of metal structures in or near plants. There is increasing pressure from state regulatory agencies to limit SO{sub x} emissions, and Maximum Achievable Control Technology (MACT) criteria under the CAA continue to evolve. Therefore, it is important that ceramic producers understand the sources of SO{sub x} emissions and the strategies for reducing them. Moreover, with proposed new changes in the CAA by the Environmental Protection Agency (EPA), it is important for the ceramic industry to be able to exert appropriate influence in a time of regulatory uncertainty.