The formation of persistent organic pollutants such as polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs), known collectively as dioxins, is a recognized concern for cement manufacturing. Dioxins have the potential to form if chlorine is present in the input fuel or raw materials. Formation can be repressed, however, by the high temperatures and long residence times that are standard in cement kilns (Karstensen 2008). Minimizing dioxin formation is further achieved by limiting the concentration of organics in the raw material mix, and by quickly cooling the exhaust gases in wet and long dry kilns (WBCSD 2002; Karstensen.
