A desulfurization process using magnesium sulfites in a clear solution has the discharge from a wet scrubbing unit passed to a reaction tank. A silica-containing solid particulate material, such as sand, is added to the reaction tank and lime is added to precipitate calcium sulfite solids onto the particulate material. The resulting solids, a calcium sulfite coated, silica containing solid particulate material is readily dewatered and may be used as a cement manufacturing process.