Method for producing an aqueous sodium chloride solution and use thereof
AssigneeSolvay (Societe Anonyme)
InventorsLeon Ninane, Jean-Francois Adam
Life of this patent
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Abstract
Method for producing an industrial aqueous sodium chloride solution (22) in which an aqueous solution of sodium chloride (20) containing polyvalent metals and constituting a mother liquor obtained from the precipitation (14) of hydroxides of said metals from an aqueous solution (6) of hydrochloric acid is obtained from washing (3,4) fumes (1) containing hydrogen chloride and originating from the oxidation of chlorinated products, is treated on a chelating Na-type resin. The aqueous sodium chloride solution obtained in this manner has applications in the production of aqueous sodium hydroxide solutions by means of electrolysis or electrodialysis and in the production of sodium chloride crystals by means of evaporation.
Claims12
A process for producing an aqueous sodium chloride solution comprising steps for:
- (a) washing a fume containing hydrogen chloride and metal compounds, the metal of said compound being polyvalent, with acidified water to dissolve said hydrogen chloride and metal compounds, to form an aqueous hydrochloric acid solution;
- (b) alkalinizing with sodium hydroxide said aqueous hydrochloric acid solution to a pH value of from 8 to 11, to form an aqueous suspension of metal hydroxide of said metal of said compounds;
- (c) separating said suspension into said metal hydroxide and a mother liquor containing dissolved polyvalent metal cations and aqueous sodium chloride;
- (d) treating said mother liquor on a chelating resin having sodium cations as interchangeable cations, to extract said dissolved metal cations from said mother liquor;
- and
- (e) separating an aqueous sodium chloride solution from the chelating resin.
A process for producing an aqueous sodium chloride solution comprising steps for:
- (a) washing a fume containing hydrogen chloride and metal compounds, the metal of said compound being polyvalent, with acidified water to dissolve said hydrogen chloride and metal compounds, to form an aqueous hydrochloric acid solution;
- (b) alkalinizing with sodium hydroxide said aqueous hydrochloric acid solution to a pH value of from 8 to 11, to form an aqueous suspension of metal hydroxide of said metal of said compounds;
- (c) separating said suspension into said metal hydroxide and a mother liquor containing dissolved polyvalent metal cations and aqueous sodium chloride;
- (d) treating said mother liquor on a chelating resin having sodium cations as interchangeable cations, to extract said dissolved metal cations from said mother liquor;
- (e) separating an aqueous sodium chloride solution from the chelating resin;
- and
- (f) electro(dia)lysis of said aqueous sodium chloride solution.
A process for producing sodium chloride crystals comprising steps for:
- (a) washing a fume containing hydrogen chloride and metal compounds, the metal of said compound being polyvalent, with acidified water to dissolve said hydrogen chloride and metal compounds, to form an aqueous hydrochloric acid solution;
- (b) alkalinizing with sodium hydroxide said aqueous hydrochloric acid solution to a pH value of from 8 to 11, to form an aqueous suspension of metal hydroxide of said metal of said compounds;
- (c) separating said suspension into said metal hydroxide and a mother liquor containing dissolved polyvalent metal cations and aqueous sodium chloride;
- (d) treating said mother liquor on a chelating resin having sodium cations as interchangeable cations, to extract said dissolved metal cations from said mother liquor;
- (e) separating an aqueous sodium chloride solution from the chelating resin;
- and
- (f) evaporating said aqueous sodium chloride solution to obtain sodium chloride crystals.
Dependencies are inferred from the claim text.