Patent ID: 6210583
Filing Date: 2001-04-03
Classification: B01D,C02F,Y02P

Abstract:
A process for treating a spent caustic stream, comprising:(a) feeding the spent caustic stream to a multi-stage countercurrent liquid-liquid extractor, the extractor having an upper end and a lower end, the spent caustic being introduced proximate to the upper end;(b) feeding a solvent stream to the lower end of the extractor;(c) withdrawing a spent caustic raffinate stream from the lower end of the extractor;(d) distilling the spent caustic raffinate stream in a steam distillation unit to provide a pretreated spent caustic stream,(e) subjecting the pretreated spent caustic stream to wet air oxidation to produce an oxidized spent caustic stream containing sodium sulfate, and(f) contacting the oxidized spent caustic stream with an oxygen/ozone gas mixture for a time sufficient to produce a further quantity of sodium sulfate.