Process for removing sodium sulfate from highly concentrated solution of sodium chloride

摘要

A process for removal of sodium sulfate from a highly concentrated solution of sodium chloride solves the problem of reducing the concentration of sodium sulfate in the electrolyte used in the production of chlorine, so that the electrolyte can be returned back into the production process for repeated use.;After dechlorination the solution of drained electrolyte is collected in an accumulating vessel, wherein the solution is cooled down to 15 °C - 20 °C and its pH value is set to 9 to 13 by means of NaOH solution. The solution is then poured into a conically shaped vessel equipped with an assembly for deep-freezing, wherein the solution is frozen to -5 °C to -20 °C to facilitate the formation of sulfate crystals. In the melting phase of the process the sodium sulfate crystals segregate from the solution and drop to the bottom of the conical vessel.