Experimental investigation on pyrolysis of coking waste salts: Mechanism of organic compounds removal and salt agglomeration.

Evaporative crystallization of high-salinity wastewater produces hazardous waste salts. This study aimed to investigate coking waste salt (CWS) and employed pyrolysis to eliminate organic impurities. The pyrolysis mechanism, properties, and agglomeration characteristics of CWS were examined. Results showed that pyrolysis disrupts the functional groups of organic compounds, but benzene rings are resistant to removal. Below 500 °C, pyrolysis in air was more effective than pyrolysis in N2, whereas above 500 °C, the difference between pyrolysis in air and N2 was negligible. Agglomeration was primarily attributed to deliquescence caking, pyrolysis of organic matter, and low-melting-point salts. The optimal disposal method for CWS involved drying and crushing, followed by pyrolysis in air at 450 °C. This process minimized agglomeration and maximized organic matter removal. Our findings provide a robust theoretical basis and practical guidance for waste salt resource utilization.