The term "gypsum residue" here refers to gypsum-containing by-products generated and discharged during phosphate fertilizer production, wet desulfurization, fluorine-based chemical processing, and other chemical processes, primarily composed of calcium sulfate dihydrate along with minor impurities. After collection, dewatering, impurity removal, and processing, such gypsum residue can be recycled as a resource for applications such as cement retarders, construction material additives, soil conditioners, or the production of gypsum products.