Patent ID: 8043426

Claim:
A method for treating waste cement kiln dust containing alkaline metal salts comprising the steps of: a.) providing a cement kiln dust containing alkaline metal salts and water; b.) mixing the kiln dust and water to form a mixture containing calcium hydroxide by the hydration process; c.) drying the mixture from step b); d.) fractionating the dried mixture from step c) by sieving; e.) providing a fluid bed column reactor including an inverted cone-shaped gas distributor with a base, a truncated apex and a distributor plate having a plurality of openings disposed in a generally circular array at said base through which an ascending current of fluidized gas passes and on which base the particles rest when the reactor is shut down; and f.) carbonation of the dried fractionated and hydrated mixture from step d) with cement kiln exhaust gas containing a pollutant selected from the group consisting of acidic oxides of sulfur, nitrogen, carbon, halogen compounds and mixtures thereof in the fluid bed reactor to form a stable material.