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US 4,289,739 AGranted
Method of producing crystalline sodium aluminum phosphate
AssigneeFMC Corporation
InventorsJohn S. Chiang, Theodore F. Munday, Joseph M. Ilardi
Life of this patent
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Abstract
In the production of SALP tetrahydrate wherein sodium carbonate and aluminum hydroxide are added to aqueous phosphoric acid, the viscous reactive mixture is agitated with water to free the SALP tetrahydrate crystals from the gelatinous matrix. The crystals are recovered by filtration or centrifugation.
Claims17
In the method of manufacturing crystalline acidic sodium aluminum phosphate of the formula:
- NaAl.sub.3 H.sub.14 (PO.sub.4).sub.8.4H.sub.2 O
- by contacting a reactive sodium compound and a reactive trivalent aluminum compound with aqueous phosphoric acid, the sodium and aluminum compounds being in stoichiometric proportions to provide one sodium atom for each three aluminum atoms and the phosphoric acid being in excess of the amount required to react with all of said sodium and aluminum compounds, and concentrating the resulting solution to effect crystallization of the sodium aluminum phosphate, the improvement of separating the crystals of sodium aluminum phosphate from the resulting viscous crystallization mixture by rapidly diluting said mixture with water in the absence of added organic solvent while maintaining vigorous agitation to produce a liquid suspension of said crystals in aqueous phosphoric acid and immediately recovering the crystals from the aqueous phosphoric acid.
Dependencies are inferred from the claim text.