Purification of wet process phosphoric acid
AssigneeAlbright & Wilson Limited
InventorsEdward J. Lowe, Michael W. Minshall, Arthur Wilson
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Abstract
Wet process phosphoric acid is heated by passing alternating current through the acid, preferably in carbon apparatus to concentrations above 76% P.sub.2 O.sub.5 and preferably temperatures above 500.degree. C. to remove sulphate and fluoride and convert organic and basic impurities into a filterable precipitate; the acid is separated from the precipitate preferably after dilution with water to provide a high purity crystallizable product.
Claims39
A method for the production of purified phosphoric acid or phosphatic derivatives of wet process phosphoric acid which comprises heating wet process phosphoric acid in an evaporator vessel having carbon walls which are electrically conducting and which are stable to the concentrated phosphoric acid at the evaporation temperatures, to evaporate water therefrom to leave a concentrated acid by direct electrical resistance heating by passing an alternating current through said wet process acid until the concentration of said acid is at least 76% by weight P.sub.2 O.sub.5, precipitating solid impurities in said concentrated acid and separating solid impurities from the purified phosphoric acid or phosphatic derivative.
Dependencies are inferred from the claim text.