Pigment alumina

The spray method was used to produce alumina pigments doped with Cr, Mn, and Co. In these experiments, Al(.vec-OBu)3 was mixed with solutions of the corresponding metal nitrates in. veobutoxide, the resulting liquids were nebulized, and then the droplets were hydrolyzed (76). The major purpose of these studies was to obtain inorganic pigments and to evaluate their color properties by altering the amount of dopants in the aluminum oxide matrix. For the same reason, the vanadium... 

Transparent white pigments (extenders) commonly used in inks, in order of decreasing transparency, ate alumina hydrate, magnesium carbonate, calcium carbonate, blanc fixe (precipitated barium sulfate), talc, and clay. Extenders ate sometimes used to reduce the color strength and change the theology of inks. 

Though functionally and chemically similar, fillers and pigments ate distinguished from one another in that fillers are added at the wet end of the paper machine, and serve to fill the sheet pigments are added at the size press and serve to alter the surface of the sheet. The most common fillers are mineral pigments, eg, clay, titanium dioxide [13463-67-7] calcium carbonate, siUca [7631-86-9], hydrated alumina [21645-51 -2], and talc [14807-96-6]. 

Anhydrous aluminum chloride, AIQ, is manufactured primarily by reaction of chlorine [7782-50-5] vapor with molten aluminum and used mainly as a catalyst in organic chemistry ie, in Friedel-Crafts reactions (qv) and in proprietary steps in the production of titanium dioxine [13463-67-7] Ti02, pigment. Its manufacture by carbochlorination of alumina or clay is less energy-intensive and is the preferred route for a few producers (19). 

Two pigment production routes ate in commercial use. In the sulfate process, the ore is dissolved in sulfuric acid, the solution is hydrolyzed to precipitate a microcrystalline titanium dioxide, which in turn is grown by a process of calcination at temperatures of ca 900—1000°C. In the chloride process, titanium tetrachloride, formed by chlorinating the ore, is purified by distillation and is then oxidized at ca 1400—1600°C to form crystals of the required size. In both cases, the taw products are finished by coating with a layer of hydrous oxides, typically a mixture of siUca, alumina, etc. 

Uniformity and Reproducibility. For most ceramic pigments rapid, uniform, and reproducible conversion to the desired product requires great care in production (40). Adjustment of each lot to standard, using toners, is usually required. The Victoria green garnet, the manganese alumina pink comndum, and the chrome—tin pink sphene are noteworthy for their difficulty in making reproducible product. 

In this article, we will discuss the use of physical adsorption to determine the total surface areas of finely divided powders or solids, e.g., clay, carbon black, silica, inorganic pigments, polymers, alumina, and so forth. The use of chemisorption is confined to the measurements of metal surface areas of finely divided metals, such as powders, evaporated metal films, and those found in supported metal catalysts. 

Red mud Production of alumina Minor utilization, rest in lagoons Pigment in paints and plastics... 

Cobalt ores are often found in association with copper(II) sulfide. Cobalt is a silver-gray metal and is used mainly for alloying with iron. Alnico steel, an alloy of iron, nickel, cobalt, and aluminum, is used to make permanent magnets such as those in loudspeakers. Cobalt steels are hard enough to be used as surgical steels, drill bits, and lathe tools. The color of cobalt glass is due to a blue pigment that forms when cobalt(II) oxide is heated with silica and alumina. 

Titanium dioxide (E171, Cl white 6) is a white, opaque mineral occurring naturally in three main forms rutile, anatase, and brookite. More than 4 million tons of titanium dioxide are produced per year and it is widely used for industrial applications (paints, inks, plastics, textiles) and in small amounts as a food colorant. ° "° Production and properties — Titanium oxide is mainly produced from ilmenite, a titaniferous ore (FeTiOj). Rutile and anatase are relatively pure titanium dioxide (Ti02) forms. Titanium oxide pigment is produced via chloride or sulfate processes via the treatment of the titanium oxide ore with chlorine gas or sulfuric acid, followed by a series of purification steps. High-purity anatase is preferred for utilization in the food industry. It may be coated with small amounts of alumina or silica to improve technological properties. 

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