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1. (WO1994001497) METHOD FOR PREPARING HIGHLY-COLORIFIC HIGH-PURITY BISMUTH VANADATE BASED PIGMENTS

Pub. No.:    WO/1994/001497    International Application No.:    PCT/BE1993/000047
Publication Date: Jan 20, 1994 International Filing Date: Jul 8, 1993
IPC: C01G 31/00
C09C 1/00
Applicants: COLOUR RESEARCH COMPANY (CORECO) LTD.
VERMOORTELE, Frank
BUYSE, Emile, Joseph
Inventors: VERMOORTELE, Frank
BUYSE, Emile, Joseph
Title: METHOD FOR PREPARING HIGHLY-COLORIFIC HIGH-PURITY BISMUTH VANADATE BASED PIGMENTS
Abstract:
A method for preparing a bismuth vanadate based pigment by (1) reacting an acidic bismuth nitrate solution with an alkaline ammonium metavanadate solution and optionally with other salts, to form a bismuth vanadate based precipitate in a highly acidic reaction medium with a pH of 1-2; (2) adding a base until the pH of the reaction medium is around 7; (3) raising the temperature to over 80 °C in around 30 minutes while holding the pH at 7 by means of a base; (4) stirring for 30 minutes to over 2 hours until the pH is around 6.5; and (5) filtering, washing and drying the pigment. The resulting products and their use in dyeing paints, lacquers and/or plastics are also disclosed.