Heat stable iron oxides
AssigneePfizer Inc.
InventorDennis B. Vanderheiden
Life of this patent
Estimating the term…
Abstract
A thermally stable oxide product comprising particulate iron oxide coated with an insoluble metal metaphosphate in the amount of at least 1 percent by weight based on the weight of said product, wherein said iron oxide is hydrated ferric oxide or ferroso-ferric oxide, and wherein said metal is aluminum, barium, calcium, magnesium, iron or zinc, and said product is characterized by a procedural decomposition temperature of at least about 230.degree. C. for the hydrated ferric oxide and about 180.degree. C. for the ferroso-ferric oxide and a heat soak .DELTA.E of at most about 4.0 for the hydrated ferric oxide and about 5.0 for the ferroso-ferric oxide. A process claim is also asserted.
Claims13
A coated particle comprising an iron oxide and a protective coating of insoluble metal metaphosphate wherein the coating comprises between about 1% and 20% of the total particle weight.
A thermally stable oxide product, said product comprising particulate iron oxide coated with an insoluble metal metaphosphate in the amount of at least 1% by weight based on the weight of said product, wherein said iron oxide is a hydrated ferric oxide or ferroso-ferric oxide and wherein said metal is aluminum, barium, calcium, magnesium, iron or zinc, and said product is characterized by a procedural decomposition temperature (pdt) of at least about 230.degree. C. for the hydrated ferric oxide and about 180.degree. C. for the ferroso-ferric oxide and a heat soak .DELTA.E of not more than about 4.0 for the hydrated ferric oxide and 5.0 for the ferroso-ferric oxide.
Dependencies are inferred from the claim text.