GB626641A - A process for the production and purification of common salt and other components from brine, including the dehydration of glauber salt - Google Patents

Abstract

Impurities in solid sodium chloride are removed by treatment with hydrochloric acid solution, which is subsequently recovered from the dissolved impurities by distillation. In an example, a brine solution is, if desired, treated with solid soda ash, or a concentrated solution thereof to precipitate magnesium carbonate, which when dried may be added to table salt, and the filtrate evaporated to dryness in a multiple effect evaporator and/or by a solar process. The solid salt is treated with hydrochloric acid solution of 1.10-1.15 sp. gr. at 0-110 DEG C., preferably under reflux, ands the solution then withdrawn. The salt is washed with a saturated salt solution, and traces of acid neutralized with soda. Sodium sulphate resulting from the evaporation of the hydrochloric acid for reuse, is refluxed up to boiling with an aqueous solution of pure ethyl alcohol, or denatured alcohol, or decolourized methylated spirits containing say 2-75 per cent water. Sodium chloride present in the sulphate is thereby dissolved. Glauber salt is separated from the cooled solution and washed with an alcohol solution. If dehydrated sodium sulphate is required, refluxing above 34 DEG C. is effected.