Pigments coloured inorganic

A recent survey of the technical and environmental aspects of inorganic pigments by Schwarz and Endriss [33] has put the importance of these products into numerical perspective. Of a total worldwide production of some 5M tonnes of pigments, 96% are inorganic. Of this 4.8M tonnes, carbon black and various whites account for 84%, that is just over 4M tonnes. This means that world production of coloured inorganic pigments is approximately 0.8M tonnes. 

The major use (60%) for coloured inorganic pigments, such as iron oxides, is in the construction materials industry. Here they are used to colour roof and flooring tiles, fibrous cement and mortar. Many inorganic pigments are used in coloured baking enamels for metal appliances. Chromium oxide is used in the refractory industry, not for its colour but because of its ability to improve the properties of bricks used in furnace linings. 

The most important coloured inorganic pigments are iron oxides, which provide shades ranging from yellow and red to brown and black. These pigments are manufactured either from natural deposits or by synthetic routes. However, the S3mthetic products, which offer the advantages over their natural counterparts of higher chemical purity and better... 

This book is focused on the industrially important organic dyes and pigments and, to a certain extent, inorganic pigments and thus deals almost exclusively with colour generated by the mechanisms described by group (c). 

Pigments are coloured, black, white or fluorescent particulate organic or inorganic sohds, which are insoluble in, and essentially physically and chemically unaffected by, the vehicle or substrate in which they are incorporated. They alter appearance by selective absorption and/or scattering of light. 

This chromogen (1.13) is somewhat reminiscent of the indigoid and anthraquinone types but it has not yielded useful vat dyes. Bluish red pigments of the quinacridone class are especially important in violet and magenta colours or for deep reds in admixture with inorganic cadmium scarlets. 

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