Mineral-Pigment Solutions

Huber Engineered Materials Mineral-Pigment Solutions Bayer... 

Reddish blue (Cl Blue 29), pink (Cl Red 259), and violet (Cl Violet 15) shades can be produced. Cl Blue 29 has FDA sanction for indirect food contact, and is widely used in cosmetics (ASTM D262). Most manufacture has shifted away from North America and Western Europe. Suppliers include Mineral Pigment Solutions Inc. (MPSI), formerly Whittaker, Clark and Daniels Holiday Pigments, trade name Artizan Habich GmbH Nubiola (Barcelona) and PD Industries and Ultramarine Pigments Ltd of India. 

J. Rius, E. Elkaim and X. TorreUes, Structure determination of the blue mineral pigment aerinite from synchrotron powder diffraction data The solution of an old riddle, European Journal of Mineralogy, Vol. 16, No 1,127-134,2004. 

Hot springs may contain lots of different minerals in solution. Upon reaching the surface, these waters cool off and the compounds held in solution will precipitate around vents or pools. The most common deposits around hot springs are composed of calcite or common opal. Both of these minerals are colorless when pure, but are often colored by other materials in the water. Oxides of iron are the most common pigments in these situations. In shades of brown, red, and yellow, iron oxide may color an entire deposit, or appear episodically, dyeing some layers and not others. 

Cobalt(II) phosphate octahydrate [10294-50-5], Co2(P0272 8H20, is a red to purple amorphous powder. The product is obtained by reaction of an alkaline phosphate and solutions of cobalt salts. The material is insoluble in water or alkaU, but dissolves in mineral acids. The phosphate is used in glazes, enamels, pigments (qv) and plastic resins, and in certain steel (qv) phosphating operations (see Enamels,PORCELAIN ORVITREOUS). 

Capillary Flow Moisture which is held in the interstices of solids, as liquid on the surface, or as free moisture in cell cavities, moves by gravity and capiUarity, provided that passageways for continuous flow are present. In diying, liquid flow resulting from capiUarity appUes to liquids not held in solution and to aU moisture above the fiber-saturation point, as in textiles, paper, and leather, and to all moisture above the equiUbrium moisture content at atmospheric saturations, as in fine powders and granular solids, such as paint pigments, minerals, clays, soU, and sand. 

Obviously, in solution, 83 is not stable against oxidation. It is stable in the mineral lapis lazuli, and the industrial ultramarine blue pigment [28]. In these materials, the radical 83 is encapsulated in the -cages of the sodalite structure, which protects it against oxidation. In ultramarine pigments, another radical anion polysulfide, 82 , has been observed. 

Production. The raw material for the production of cadmium yellow pigments is high-purity cadmium metal (99.99 %), cadmium oxide, or cadmium carbonate. If the metal is used it is first dissolved in mineral acid. A zinc salt is then added to the solution the amount added depends on the desired shade. The zinc salt is followed by addition of sodium sulfide solution. An extremely finely divided cadmium sulfide or cadmium zinc sulfide precipitate is formed, which does not possess any pigment properties. This intermediate product can also be obtained by mixing the cadmium or cadmium-zinc salt solution with sodium carbonate solution. An alkaline cadmium carbonate or cadmium zinc carbonate precipitate is formed which reacts in suspension with added sodium sulfide solution. 

Production. Cadmium red pigments are produced in a similar way to the cadmium yellow pigments. The cadmium salt solution is prepared by dissolving the metal in mineral acid and then sodium sulfide is added. A certain amount of selenium powder is dissolved in the sodium sulfide solution to obtain the desired color shade. In an alternative procedure, the cadmium solution is mixed with sodium carbonate solution to precipitate cadmium carbonate which is reacted with the selenium-containing sodium sulfide solution. 

This remaining pigment often, however, contains small quantities of oil, either saponified or oxidised. These may be removed by means of dilute alcoholic caustic potash, when this is without action on the colour, or the oxidised fatty acids may be extracted with phenol, which readily dissolves them and does not act on mineral colours. On the other hand, small quantities of certain pigments may pass into the ethereal solution in combination with the fatty acids these may be separated by shaking the ethereal liquid with an appropriate acid, in which the mineral substances are then sought. 

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