Calcium chloride purification
AssigneeSunoco, Inc. (R&M)
InventorManoj V. Bhinde
Life of this patent
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Abstract
Significant amounts of soluble fluoride, known to create problems in processes requiring high quality grade calcium chloride, are removed from calcium chloride solution using hydroxyapatite as a removal mechanism. Under acidic conditions, calcium chloride solution is purified to about less than 10 ppm fluoride, significantly, to less than 1 ppm fluoride. At least 0.1 weight percent hydroxyapatite and concentrated hydrochloric acid are added to calcium chloride solution and slurried to remove fluoride and create a highly purified calcium chloride solution, substantially free of fluoride.
Claims11
A method of removing fluoride from calcium chloride comprising mixing calcium chloride solution with hydroxyapatite in the presence of an acid.
A method for removing soluble fluoride from a calcium chloride solution comprising:
- mixing said calcium chloride solution with hydroxyapatite and an acid to form a slurry at a pH less than about 2 for at least 1 minute, and filtering out a purified calcium chloride solution.
A method for producing ultra-low fluoride food-grade calcium chloride comprising mixing a calcium chloride solution with hydroxyapatite and an acid to form a slurry at a pH of less than 2 for at least 1 minute, and filtering out purified calcium chloride solution.
A method of producing calcium chloride with an ultra-low fluoride concentration comprising mixing hydroxyapatite, hydrochloric acid, and a calcium source.
Dependencies are inferred from the claim text.