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US 6,911,191 B2Granted
One-step oxidation of wet-process phosphoric acid
AssigneeAgrium U.S. Inc.
InventorsDaniel Carl Neuman, Russell Dean Alcorn, Bryce Richard Carpenter
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Abstract
A one-step method for production of green-colored, stabilized wet-process phosphoric acid in which black-colored, wet-process phosphoric acid containing incidental metallic impurities and a carbonaceous content of less than 1000 ppm is oxidized to produce a green-colored liquid having a carbonaceous content less than 500 ppm. A typical green-colored liquid product produced by this one-step process has an emf of greater than 800 mv.
Claims17
A method for making a green-colored, stabilized wet-process phosphoric acid comprising:
- providing a black-colored wet-process phosphoric acid having a P2O5 content of from 30% by weight to about 75% by weight which contains incidental metallic impurities and a total carbonaceous content of less than about 1000 ppm;
- oxidizing said wet-process phosphoric acid at a temperature less than 400° F. with a chloride- or nitrogen-based oxidizing agent, said oxidizing of said wet-process phosphoric acid being conducted until a clear green-colored liquid product is obtained with a carbonaceous content less than 500 ppm.
Dependencies are inferred from the claim text.