The paper summarizes the results of an experimental study that focused on the production of high surface area materials from various sorbents. (NOTE: Injecting calcium-based sorbents into coal burning utility boilers to control SO2 emissions is being considered by the EPA as an acid rain control technology because capital equipment requirements are small and the process is entirely dry. Both theoretical calculations and experimental results indicate that SO2 capture is strongly related to the surface area of the calcined sorbent. Thus, an improved understanding of the formation of surface area is required for the complete optimization of the sorbent injection process.) Weight loss and B.E.T. surface area data were obtained as a function of residence time and furnace temperature for 14 different sorbents which were members of 4 distinct classes: limestones, dolomites, hydrated limes, and pressure hydrated dolomitic limes. The results demonstrate major differences between classes of sorbents. In general, the hydrated limes calcined faster and produced higher surface areas than the corresponding carbonates. The dolomitic materials also produced higher surface areas than the comparable calcitic sorbents. Pressure hydrated dolomitic limes performed the best, producing surface areas in excess of 140 sq m/g; the limestones performed the worst.