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US 5,399,197 AGranted
Bismuth phosphovanadate and/or bismuth silicovanadate based yellow pigments and processes of manufacturing thereof
AssigneeColour Research Company (CORECO) Ltd.
InventorsFrank Vermoortele, Emile J. Buyse
Life of this patent
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Abstract
A bismuth vanadate based yellow inorganic pigment is disclosed together with a process for making bismuth based yellow inorganic pigments.
Claims19
A bismuth-vanadate-based yellow inorganic pigment, having the formula:
- Bi.sub.a L.sub.b M.sub.c N.sub.d O.sub.4
- where:
- L is selected from the group consisting of Si, and
- the combination of Si and one or more of the elements selected from the group consisting of Ti, Oe, and Zr, and
- the combination of Si, one or more of the elements selected from the group consisting of Ti, Ge, and Zr, and one or more of the elements selected from the group consisting of B, Al, Oa, In and Tl;
- M is selected from the group consisting of V, and
- the combination of V and one or more of the elements selected from the group consisting of V, Nb, Ta, Unp and P;
- N is an element selected from the group consisting of Mo and W;
- .ltoreq. a.ltoreq.4/3;
- 0.ltoreq.b<1;
- 0<c.ltoreq.1;
- and
- 0.ltoreq.d<1;
- provided that if c is greater than zero and b is equal to zero then M is V and one or more of the elements selected from the group consisting of V, Nb, Ta, Unp and P;
- further provided that if b and d are equal to zero then M does not include P.
12 more elements
A process of manufacturing a bismuth-vanadate-based yellow inorganic pigment comprising the steps of:
- (a) mixing an acid solution of bismuth nitrate with an aqueous solution of vanadate ions and one or more aqueous solutions selected from the group consisting of aqueous solutions of phosphate ions, silicate ions, molybdate ions, tungstate ions, Ti salts, Ge salts, Zr salts and Nb salts to form a precipitate and mother-waters;
- (b) separating the precipitate from the mother-waters;
- (c) washing the precipitate;
- and,
- (d) calcining the precipitate at a temperature of 400.degree. to 700.degree. C. for 0.5 to 5 hours to form a calcinated pigment.
2 more elements
A process of manufacturing a bismuth-vanadate-based yellow inorganic pigment comprising the steps of:
- (a) mixing powders of bismuth compounds, vanadium ions and one or more ions selected from the group consisting of the ions of silicon and phosphorus, and
- (b) calcining the resulting mixture at a temperature ranging from about 400.degree. to about 1100.degree. C. for a period of time ranging from about 1 to about 50 hours.
Dependencies are inferred from the claim text.