ABSTRACTA stabilization process for coal cleaning and coal combustion-related wastes has been developed that uses the energy derived from the fuel contained in the coal cleaning wastes. The wastes are pulverized, when necessary, formed into granules in a rotary pan agglomerator, and then fired to a sintering temperature. The result is a readily disposable product that is highly resistant to environmental degradation. Granules of refuse only, and of refuse/fly ash and refuse/FGD sludge mixtures have been investigated. About 90 wt% of the sulfur in the refuse/sludge mixtures is evolved as SO2 during the combustion/sintering portion of the process. Studies using a microreactor system have shown the generation of SO2 to be a function of temperature and to parallel the decomposition of the sulfur-containing compounds present. Based on laboratory tests, SO2 concentrations of 4–8 vol% are predicted in the SO2-rich off-gases. By-product sulfur recovery from the off-gases appears practical and attractive using current technology that is proven and well established.
Characterization of solid wastes from conventional coal combustion processes