The term "spent desulfurization agents" here refers to desulfurization materials such as limestone, lime, magnesium oxide, activated carbon, and other desulfurization materials used in flue gas, gas, or liquid desulfurization processes in industries such as iron and steel metallurgy, power, and chemical production. These materials have lost their original desulfurization function due to reaction consumption, performance degradation, or substandard quality, or although not completely losing their utility value, have been discarded. After collection, classification, and processing, they can be resourcefully utilized in recycling pathways such as by-product gypsum, regenerated adsorbents, construction materials, soil amendment, etc.