Analysis of Treatment and Resource Utilization of Coal Chemical Waste Salt: Current Status and Prospects

• • Coal chemical waste salt comprises >90% NaCl and Na2SO4, with organic pollutants (e.g., phenols, PAHs) adsorbed on crystal surfaces and inorganic impurities (heavy metals, hardness ions) posing significant environmental risks; TDS of concentrated brine can exceed 35,000 mg/L. • • Treatment follows a 'remove impurities first, then separate salts' route: organic removal via pyrolysis, advanced oxidation, or biochemical methods; inorganic deep removal via chemical precipitation-adsorption-membrane coupling; salt separation via evaporative crystallization (solubility differences) or membrane methods like electrodialysis. • • Ion-exchange membrane caustic soda production is viable for NaCl reuse, but strict control of Fe3+ and TOC is critical; for Na2SO4, the 'short-process ammonium-alkali' method is mature with engineering demonstrations, while bipolar membrane electrodialysis shows green potential but faces economic and stability challenges. • • The current standard system lacks effective integration between waste salt products, pollution control, and resource utilization; a holistic framework from pollution control to product standards to resource use is needed to drive clean, industrial, and value-added development.