IMPROVED METHOD FOR PREPARATION OF BISMUTH VANADATE PIGMENT AND NOVEL BISMUTH VANADATE PIGMENT OF HIGH TINTING STRENGTH

摘要

Improved process for preparing bismuth vanadate pigments and solid solutions based on bismuth vanadate by a) mixing a solution of a bismuth(III) salt containing if necessary one or more further metal salts or a mixture thereof with the aqueous solution of a vanadate salt containing if necessary a molybdate, tungstenate or sulphate salt or a mixture thereof, and b) subsequently aftertreating the resulting suspension to convert the initially amorphously precipitated particles into crystalline compounds, characterised in that fluoride ions are used during mixing and/or in the course of the subsequent aftertreatment stage. The pigments thus produced are notable in application in particular for high colour strength and hiding power.