Method for oxidation of flue gas desulfurization absorbent and the product produced thereby

Pellets having a diameter in the range from 0.5 mm to 5 mm composed of agglomerated particles having an average size range of from about 50.mu. to about 100.mu. and having binder components therein in an amount from about 1% to about 3%, by weight, with small amounts of impurities and inerts, the balance being essentially calcium sulfate.

In the dry flue gas desulfurization process wherein the gas is first dedusted to remove fly ash and thereafter is passed through a spray drier in which the gas is subjected to a spray of an absorbent liquid comprising milk of lime, the absorbent reacting with the sulfur dioxide in said gas while the liquid component thereof evaporates, thereby yielding a fine-grained dry spent absorbent composed primarily of calcium sulfite and calcium sulfate, the improvement whereby a useful product is obtained by treating the spent absorbent to produce pellets composed primarily of calcium sulfate, comprising providing the dry spent absorbent with relatively low-melting binder constituents in controlled amounts in the range from about 1% to about 3%, by weight, and oxidizing the absorbent in a fluidized bed reactor at a temperature of from about 700.degree. C. to about 1000.degree. C. at which temperature said binder constituents are in the liquid phase to form oxidized pellets having an average diameter of from about 0.5 mm to about 5 mm composed primarily of calcium sulfate particles having an average diameter of from about 50.mu. to about 100.mu. bound to each other by said binder constituents.