PRODUCTION OF WHITE GYPSUM

摘要

PURPOSE:To obtain an exhaust gas desulfurization gypsum having improved quality and whiteness by lowering the dust content in gypsum obtained from a wet-type limestone-gypsum exhaust gas desulfurization process. CONSTITUTION:A gypsum having high whiteness is produced by using a liquid cyclone having scrubbing function in a classification operation of a process for producing exhaust gas desulfurization gypsum from the absorbed liquid of a wet-type limestone-gypsum exhaust gas desulfurization process. The gypsum production process comprises (1) a step to extract an absorption liquid containing gypsum particles and dust from the gypsum crystallization zone of a wet-type limestone-gypsum exhaust gas desulfurization process, (2) a step to classify the absorption liquid to separate a fraction composed mainly of large sized gypsum particles from other fractions containing dust and (3) a step to adjust the water-content of the separated fraction composed mainly of large-sized gypsum particles to a prescribed level to obtain an exhaust gas desulfurization gypsum.