Abstract:The process of neutralization + sedimentation + flocculation + integrated clarification" is currently one of the commonly used methods for treating desulfurization wastewater from thermal power plants. The main by-product is desulfurization sludge, which belongs to solid waste. Accurate analysis of the hazardous characteristics of desulfurization sludge is crucial for subsequent disposal, utilization, and environmental protection supervision. Taking the desulfurization sludge generated from flue gas desulfurization in a thermal power plant as the subject, we optimized the sampling and sample preparation steps for desulfurization sludge, conducted typical physicochemical characteristic analysis, and performed in-depth analysis on the corrosivity, flammability, reactivity, acute toxicity, leaching toxicity, and toxic substance content of the desulfurization sludge. The results showed that the desulfurization sludge does not exhibit corrosivity, flammability, reactivity, acute toxicity, or leaching toxicity. Toxic substances such as mercury, arsenic, selenium, beryllium, lead, nickel, cadmium, barium, cobalt, tin, zinc, fluoride, and petroleum solvents were detected in the desulfurization sludge, but the maximum detected values were far below the limit requirements of GB 5085.3-2007, indicating no hazardous characteristic of toxic substance content. Based on comprehensive assessment, the desulfurization sludge does not exhibit hazardous characteristics and is not classified as hazardous waste. Through risk assessment, it can be further identified as Class II general industrial solid waste, with controllable risks to the soil environment. This study provides technical support for the further resource utilization of desulfurization sludge, promoting the development of China"s circular economy and ecological environment protection.