Characterization of Pollutants in Coal Chemical Industry Waste Salt and Its Resource Utilization Potential: A Case Study of a Coal Chemical Industrial Park in Northwest China

• • PCA classification of waste salts into three types (sodium sulfate, sodium chloride, high-complexity mixed) enables tailored resource utilization pathways; sodium sulfate type (Q1, Q4, Q5, Q6) and sodium chloride type (Q2) are primary targets for recycling, while high-complexity mixed salts (Q3-A, Q3-B, Q7) require advanced treatment due to main salt content ≤60%. • • Total organic carbon (TOC) in waste salts ranged from 707.9 to 7,737.9 mg·kg⁻¹, with benzo(a)pyrene concentrations frequently exceeding GB 5085.3 limits, indicating significant organic contamination that must be addressed via advanced oxidation or thermal treatment before reuse. • • The park generated 32.6×10⁴ t of waste salt in 2023, with 90% classified as general industrial solid waste and 10% as hazardous waste; among general industrial solid waste salts, coal chemical waste salt accounted for 85%, and among hazardous waste salts, over 70% originated from coal chemical processes, underscoring the scale and urgency of management. • • Resource utilization potential is limited by pollutant composition and stability; for sodium sulfate and sodium chloride type salts, advanced oxidation and crystallization purification are required to meet product standards, while high-complexity mixed salts currently rely on harmless treatment (pyrolysis, oxidation) to reduce environmental risk, with long-term need for efficient separation technologies.