Red iron oxides

European matches, mosdy of brown or black tips, are basically identical with U.S. matches ia their formulations, except that they contain ia addition red iron oxide or manganese dioxide of pigment grade ia the match heads (2). Match materials, testing methods, and related matters have been reviewed (7,8). 

Synthetic Iron Oxides. Iron oxide pigments have been prepared synthetically since the end of the seventeenth century. The first synthetic red iron oxide was obtained as a by-product of the production of sulfuric acid from iron sulfate containing slate. Later, iron oxide pigments were produced direcdy by the thermal decomposition of iron sulfates. In the 1990s, about 70% of all iron oxide pigments consumed are prepared synthetically. 

Iron Oxide Reds. From a chemical point of view, red iron oxides are based on the stmcture of hematite, a-Fe202, and can be prepared in various shades, from orange through pure red to violet. Different shades are controlled primarily by the oxide s particle si2e, shape, and surface properties. Production. Four methods are commercially used in the preparation of iron oxide reds two-stage calcination of FeS047H2 O precipitation from an aqueous solution thermal dehydration of yellow goethite, a-FeO(OH) and oxidation of synthetic black oxide, Fe O. ... 

The largest volume of synthetic red iron oxide is produced by the two-step calcination of iron(II) sulfate. In the first step, the iron(II) sulfate heptahydrate is dehydrated to a monohydrate ... 

Wet preparation of red iron oxides can involve either a hydrothermal process (see Hydrothermal processing) or a direct precipitation and growth of iron oxide particles on specially prepared nucleating seeds of Fe202- In the hydrothermal process, iron(II) salt is chemically oxidized to iron(III) salt, which is further treated by alkahes to precipitate a hydrated iron(III) oxide gel. The gel can be dehydrated to anhydrous hematite under pressure at a temperature around 150°C. 

Synthetic red iron oxides are prepared in a variety of grades from light to dark. These are sold under a variety of names, eg, Indian red, Turkey red, and Venetian red. 

Transparent red iron oxide is composed mainly of hematite, a-Ee202, having primary particles about 10 nm. It is prepared by a precipitation reaction from a dilute solution of an iron salt at a temperature around 30°C, foUowed by a complete oxidation in the presence of some seeding additives,... 

Consumer articles often use colorants (qv), reodorants, or finishing agents. Carbon black (qv) provides the best technological properties for industrial appHcations, so most mbber articles are black. Red iron oxide or other inorganic pigments are used to color mineral-filled articles. Organic... 

Red iron oxides are usually prepared by calcining the yellow oxides to form Fe202- The shade of the ted oxide depends on the characteristics of the original yellow pigment, and the conditions of calciaation and ranges from light to dark red. The product is 96—98.5% Fe202-... 

Inhibitive Pigment a pigment which retards or prevents the corrosion of metals by chemical and/or electrochemical means, as opposed to a purely barrier action. Red lead and zinc chromate are examples of inhibitive pigments as opposed to red iron oxide which has little or no inhibitive action. 

Green - chrome oxide, cobalt green, polychloro copper phthalocyanine Orange - cadmium sulphide/selenide Red - iron oxide... 

Laux Also called the Aniline process. A process for making red iron oxide pigment in the course of making aniline by reducing nitrobenzene with scrap iron ... 

REDEX process, 3 606 Red-figures ceramic techniques, 5 745 Red fuming nitric acid, 17 188 Redingtonite, 6 4 7 It Red iron oxide(s), 19 397, 398-399 wet preparation of, 19 399 Redistribution technology, 19 816 Red Lake C... 

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