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
Coal chemical industry waste salt, generated from high-salinity wastewater treatment, poses a bottleneck for green transformation under the 'dual carbon' strategy due to its low value and high complexity. This study investigated a typical coal chemical industrial park in Northwest China, using principal component analysis (PCA) on actual waste salt samples to identify pollutant characteristics and assess resource utilization potential. Results showed total organic carbon (TOC) ranged from 707.9 to 7,737.9 mg·kg⁻¹, with benzo(a)pyrene concentrations frequently exceeding the limits of the 'Identification Standards for Hazardous Wastes' (GB 5085.3). Hardness ions and metal ions also surpassed relevant product standards. PCA classified the waste salts into three types: sodium sulfate type, sodium chloride type, and high-complexity mixed salt, each corresponding to distinct resource utilization pathways. The study proposes differentiated technical routes based on PCA classification, providing a feasible reference for classified management and technology selection. This research supports the national policy of 'harmless pretreatment + resource utilization' for waste salt, contributing to green and high-quality development of the coal chemical industry.