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US 5,399,335 AGranted
Process for preparing bismuth vanadate pigments
AssigneeCiba-Geigy Corporation
InventorRobert M. Sullivan
Life of this patent
Estimating the term…
Abstract
Bismuth vanadate (BiVO.sub.4) is prepared by reaction in nitric acid suspension of a solid bismuth-containing compound and a solid vanadium-containing compound while being subjected to milling at a temperature from 20.degree.-100.degree. C. The bismuth vanadate prepared by this process is a bright, high tinting yellow pigment particularly useful in pigmenting polymers and paints.
Claims22
A process for the preparation of yellow pigmentary bismuth vanadate which comprises
- (a) preparing a suspension of 10-50% by weight, based on the total suspension, of a mixture of a solid bismuth compound and a solid vanadium compound where the molar ratio of bismuth:vanadium is 1:1 to 1:0.8, and of 90-50% by weight, based on the total suspension, of an aqueous mineral acid solution at a pH about 1,
- (b) wet grinding the suspension from step (a) at a temperature between 0.degree. C. and 100.degree. C. until the bismuth compound and the vanadium compound are transformed into the yellow pigmentary bismuth vanadate, and
- (c) isolating the bismuth vanadate from the mineral acid solution.
Dependencies are inferred from the claim text.