18 августа, 2015 
Pokraskin Bismuth vanadate pigments are obtained by a precipitation process in which caustic soda or sodium hydroxide is added to a solution containing bismuth nitrate, sodium or ammonium vanadate, sodium molybdate (where specified) and nitric acid. The precipitate of oxides and hydroxides is washed until it is free of salt. To form better crystals and hence improve the pigment properties, the intermediate product is tempered at 200 to 700 °C. Layers of stabilizer are then applied to the surface of the crystals in subsequent precipitation steps, and are sometimes also calcined. In the case of the thermostable type, these layers are dense, glass-like coatings composed mainly of silicates. Further washing, drying and milling operations follow. To produce free-flowing, low-dusting fine granules, the pigment suspension is spray-dried and automatically packed.
The wastewater from the production process is fed to a neutralization step in which soluble heavy metals are precipitated, and suspended pigment particles allowed to settle out. A denitrification step may be employed to lower the nitrate content.
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