Sulfate removal from alkali metal chlorate solutions and production of alkali metal chlorate including said removal
AssigneeKrebs & Cie
InventorsIstvan Szanto, Marc Dietrich
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Abstract
A process for the removal of substantially chromium free sulfate from aqueous alkali metal solutions containing chromate and sulfate which includes mixing the solutions while having a pH of between about 2.5 and 4.5 with a calcium-containing material for a time and at a temperature sufficient to form a gypsum precipitate and separating that precipitate from the solutions; as well as a process for the production of alkali metal chlorate by electrolysis of alkali metal chloride including the removal of chromium free sulfate.
Claims16
A process of removing substantially chromium free sulfate from a chromate and sulfate-containing aqueous alkali metal chlorate solution comprising:
- (a) adjusting the pH of said chlorate solution to a value between 2.5 and 4.5;
- (b) mixing the pH adjusted-chlorate solution with a calcium-containing material for a time and at a temperature sufficient to form a sulfate-containing precipitate, the precipitate being predominantly gypsum;
- and
- (c) separating said gypsum precipitate from said solution.
A process of removing substantially chromium free sulfate from a chromate and sulfate-containing aqueous alkali metal chlorate solution comprising:
- (a) adjusting the pH of said chlorate solution to a value of between 2.5 and 4.5;
- (b) mixing the pH adjusted-chlorate solution with a calcium-containing material for a period of 1-2 hours and at a temperature of 30.degree. C.-50.degree. C. to thereby form a sulfate-containing precipitate, the precipitate being predominantly gypsum;
- and
- (c) separating said gypsum precipitate from said solution.
Dependencies are inferred from the claim text.