Sulfate removal from alkali metal chlorate solutions
AssigneePPG Industries, Inc.
InventorsBernard A. Maloney, John E. Carbaugh
Life of this patent
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Abstract
A process for the removal of essentially chromium-free sulfate from a chromate and sulfate-containing chlorate liquor which includes mixing the chlorate liquor having a pH of between about 2.0 and 6.0 with a calcium-containing material at a temperature and for a time sufficient to form a sulfate-containing precipitate predominantly of glauberite, Na.sub.2 Ca(SO.sub.4).sub.2, and separating the substantially chromium-free glauberite from the chlorate liquor.
Claims18
A process of removing sulfate from aqueous alkali metal chlorate solutions comprising:
- (a) mixing a chromate and sulfate-containing aqueous alkali metal chlorate solution having a pH in the range from about 2.0 to about 6.0 with a calcium-containing material for a time and at a temperature sufficient to form a sulfate-containing precipitate, the precipitate being predominantly glauberite;
- and
- (b) separating the sulfate-containing precipitate from the solution.
A process of removing sulfate from an aqueous sodium chlorate solution containing sodium chloride, sodium dichromate and sodium sulfate, comprising:
- (a) mixing the aqueous sodium chlorate solution having a pH of between about 2.0 and about 6.0 with a calcium-containing material, thereby to precipitate a portion of the sulfate in the form of glauberite and non-glauberite species;
- (b) maintaining the resulting sodium chlorate solution and sulfate-containing precipitate at a temperature and for a time sufficient to substantially completely convert the non-glauberite species to glauberite;
- and
- (c) separating said glauberite from the sodium chlorate solution.
A process of reducing chromium contamination in a sulfate-containing precipitate from an aqueous chromate and sulfate-containing sodium chlorate solution comprising:
- (a) mixing the sodium chlorate solution having a pH of between about 2.0 and 6.0 with
- (b) a calcium-containing material for a time and at a temperature sufficient to form a sulfate-containing precipitate being substantially glauberite.
Dependencies are inferred from the claim text.