An aqueous process was developed to regenerate spent alkaline sorbent materials used to control SO/sub 2/ in flue gases from coal burning power plants. Two alternate regeneration processes were also studied. Dry sorbent injection, directly into the flue gas duct of a coal-burning power plant, has been investigated by GFETC as an SO/sub 2/ control technology since 1975. The sorbent reacts with sulfur dioxide in the flue and is then collected in a baghouse or in an electrostatic precipitator. Sodium alkalis such as trona, nahcolite, and sodium bicarbonate are utilized as the sorbent material. The spent sorbent material collected in a baghouse consists of coal-derived flyash, sodium sulfate derived from reacted sorbent, and sodium carbonate derived from unreacted sorbent. Regeneration of sorbent from spent sorbent material is highly desirable to alleviate the sorbent cost and availability problems of a nonregenerative desulfurization system, and to alleviate the leaching and pollution problems of soluble sodium compounds when disposing of spent sorbent materials in landfills. Consequently, this project was initiated to develop a continuous, aqueous-based process for regeneration of sodium carbonate-type sorbents from spent sorbent/flyash materials. The specific project objectives are to: (1) retain process simplicity and to avoid difficult process conditions, so that it would be adaptable to a utility power station;(2) to maximize the recovery of sodium values in the spent sorbent; (3) to minimize the process costs and energy requirements; (4) to maximize the reactivity of the regenerated sorbent; and (5) to produce process waste materials that may be disposed of in an environmentally-acceptable manner.