Synergistic promotion of low-temperature pyrolysis and chloride complexation in waste salt purification process

Organic waste salt is a high salt hazardous waste produced by the industrial processes. Presently, there is no viable method to reclaiming and treating this issue. Using the commercial pyrocatechol monois-propyl waste salt from the manufactured pyrocatechol monois-propyl ether, a process was developed for the synergistic extraction and purification of NaCl from pyrocatechol monoisopropyl ether (OP) salt leftovers by low-temperature roasting and wet techniques (acidic ambient chloride complexation and hydrogen peroxide oxidation). After treating OP waste salt with low-temperature pyrolysis (320 °C), acidic ferric chloride complexation (pH 2–3, 0.28% FeCl₃), and neutral hydrogen peroxide oxidation (5% H₂O₂), the NaCl in the OP salt residue was purified and recovered with a purity of 98.80%. In addition, the aromatic hydrocarbons in the pyrolysis residue generated iron chloride complexes containing –OH or –COOH in the acidic system, which hastened the dissociation of the NaCl from the organic matter on the surface of the wasted salt.