Лако-красочные материалы — производство

All commercial bismuth vanadate pigments are based on pure bismuth vanadate with monoclinic or tetragonal structure. The most important properties of all bismuth vanadate pigments are — Excellent brightness of shade — Very good hiding power — High tinting strength — Very good weather fastness — High chemical resistance — Easy dispersibility — Environmentally friendly […]

Bismuth vanadate occurs naturally as the brown mineral pucherite (orthorhombic), as clinobisvanite (monoclinic) and as dreyerite (tetragonal). However, these deposits are of no practical importance to the pigment industry. Its synthesis was first reported in 1924 in a patent for pharmaceutical uses [3.104]. The development of pigments based on BiVO4 began in the mid-1970s. In […]

Greenish yellow pigments based on bismuth orthovanadate [14059-33-7], BiVO4, mar­ket introduction 1985, represent a class of pigments with interesting coloristic prop­erties. They extend the familiar range of yellow inorganic pigments, e. g. iron yellow, chrome yellow, cadmium yellow, nickel titanium yellow, and chromium titanium yel­low. In particular they substitute the greenish yellow lead chromate and […]

Two basic manufacturing processes are distinguished: the precipitation process and the powder process. Common to both of them is that the raw materials must be free of transition metal compounds, which form deeply colored sulfides (e. g. Cu, Fe, Ni, Co, Pb) [3.103]. In the precipitation process, a cadmium salt solution is reacted with sodium […]

Cadmium pigments are lightfast, stable at high temperatures, intensely colored and migration-resistant, but have only limited weather resistance. Their specific gravity is between 4.2 and 5.6 g cm-3 and their average particle size between 0.2 and 0.5 pm. They have very good hiding power and still find application in the coloring of engi­neering plastics and […]

The term “cadmium pigments” is understood in the pigment industry to refer to the pure sulfides and sulfoselenides as well as zinc-containing sulfides of cadmium. Cadmium pigments containing mercury were still used up to the middle of the last century but, because of their toxic properties, are no longer industrially significant. Cadmium sulfide occurs naturally […]

Statistical information is rarely available. The world demand in 1999 was estimated to be15,000-20,000 metric tons. The worldwide turnover with MMO was estimated to about US$ 300 millions for the same year. The main producers are BASF, CERDEC, Ciba, Heubach (Europe), Engelhard, Ferro (USA). 3.2 Cadmium Pigments | 121 3.2

Mixed metal oxides benefit from a low surface porosity (BET surfaces are typically in the range 3-6 m2 g-1 for rutile yellows and 3-10 m2 g-1 for cobalt greens and blues), resulting in low oil absorption numbers. As a consequence, high pigment loadings in color concentrates (pigment pastes, colorants and masterbatches) can be achieved. A […]

The high temperature process explains the excellent heat stability of mixed metal oxides. One known exception is chrome antimony titanate. This compound is heat stable with regard to its composition, but it can still change color upon heat treatment in some engineering plastics or some specific enamels. It is assumed that this unwanted effect relates […]

Mixed metal oxide pigments are manufactured by a solid state chemical reaction at very high temperatures of approximately 800 to 1300 °C. Raw materials include metal oxides and salts, that can be converted into oxide upon heating. During the high temperature calcination process, the mixture of metal oxides is converted into a new chemical compound, […]