Process for removing sulfur dioxide contained in a gas

摘要

A SO2 containing gas, for example a stack gas, is purified according to a multi-step process, which comprises washing said gas with an aqueous ammonia solution, treating the resulting solution with hydrochloric acid, whereby SO2 and an aqueous ammonium chloride solution are obtained and separated. The ammonium chloride solution is then reacted with magnesium oxide to recovery ammonia and the resulting magnesium chloride is cracked to produce hydrochloric acid and magnesium oxide, the ammonia, hydrochloric acid and magnesium oxide being recycled to the process.