Recovery of hydrochloric acid from galvanizing industrial effluents

Abstract

ABSTRACTThe recovery of hydrochloric acid and its separation from iron, zinc and minor elements, in the galvanizing pickling baths, were studied by solvent extraction (SX) and distillation and by distillation and crystallization. Several extractants were tested, the tri-isooctyl amine, Alamine 308, the primary aliphatic amine Primene JM-T and the mixture of four trialkylphosphine oxides, Cyanex 923. Only Cyanex 923 enabled distillation. The results indicated the feasibility of the processes to treat a real effluent using Cyanex 923 and to obtain high HCl concentrations in the distillate (256–330 g/L).