The paper discusses the development of new flyash/lime sorbents for removing SO2 from coal-fired flue gas. Flyash/lime weight ratios of 1:1 to 10:1 and several additives to these sorbents for promoting their reactivity were evaluated in a bench-scale reactor simulating conditions in a fabric filter. Of the additives tested, Na2HPO4.7H2O, (NH4)2HPO4, and H3PO4 significantly enhanced the reactivity of the dry sorbents with SO2. Alternative sources of silica were reacted with lime, and the resultant dry sorbents were shown to be highly reactive with SO2. Of the siliceous materials tested, several diatomaceous earths, montmorillonitic clays, and kaolins were identified as containing reactive silica. The morphology of the sorbents developed was characterized. This information, along with the reactor test results, was used to rate the sorbents for pilot plant evaluation.