The Materials and Manufacture of Portland Cement

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Brown printing Company, 1904 - Cement - 93 pages
 

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Page 12 - By a Portland cement is meant the product obtained from the heating or calcining up to incipient fusion of intimate mixtures, either natural or artificial, of argillaceous with calcareous substances, the calcined product to contain at least 1.7 times as much of lime, by weight, as of the materials which give the lime its hydraulic properties, and to be finely pulverized after said calcination, and thereafter additions or substitutions for the purpose only of regulating certain properties of technical...
Page 10 - ... of the clayey materials. The burning takes place at a high temperature, approaching 3,000° F., and must therefore be carried on in kilns of special design and lining. During the burning, combination of the lime with silica, alumina, and iron oxide takes place. The product of the burning is a semifused mass called clinker, and consists of silicates, aluminates, and ferrites of lime in certain definite proportions.
Page 34 - The more important of the factors are: 1. Chemical composition of the material. 2. Physical character of the material. 3. Amount of material available. 4. Location of the deposit with respect to transportation routes. 5. Location of the deposit with relation to fuel supplies.
Page 19 - Rocks of this series may therefore vary in composition from pure calcite-limestones at one end of the series to pure magnesite at the other. The term limestone has, however, been restricted in general use to that part of the series lying in composition between calcite and dolomite, while all those more uncommon phases carrying more magnesium carbonate than the 45.65 per cent.
Page 10 - Portland cement. — Portland cement is produced by burning a finely ground artificial mixture containing essentially lime, silica, alumina, and iron oxide in certain definite proportions. Usually this combination is made by mixing limestone or marl with clay or shale, in which case the mixture should contain about three parts of the lime carbonate to one part of the clayey materials.
Page 21 - Portland cement manufacturer, these variations in physical properties are of economic interest chiclly in their bearing upon two points : the percentage of water carried by the limestone as quarried, and the ease with which the rock may be crushed and pulverized. To some extent the two properties counterbalance each other ; the softer the limestone the more absorbent is it likely to be. These purely economic features will be discussed in more detail in later chapters.
Page 17 - ... travertine marls" of certain Ohio and other localities : when it took place in isolated portions of the sea through the evaporation of the sea water it gave rise to the limestone beds which so frequently accompany deposits of salt and gypsum.
Page 39 - Ini the case of hard limestones, freshly quarried, the water will commonly range from 1-2 per cent. to 3 per cent., rarely reaching or exceeding the higher figure except in the very wet quarries or during a rainy season. Such limestones, comparatively dry when quarried, are frequently sent to the grinding mills without artificial drying.
Page 55 - For coal drying, as for the drying of raw materials, the rotary drier seems best adapted to American conditions. It should be said, however, that in drying coal it is usually considered inadvisable to allow the products of combustion to pass through the cylinder in which the coal is being dried. This restriction serves to decrease slightly the possible economy of the...
Page 76 - Selma chalk, which is of marine origin, and is composed, in part at least, of the microscopic shells of Foraminifera. This formation, throughout the western part of the belt covered by it in Alabama, is about 1,000 feet in thickness, and is made up of beds of chalky and more or less argillaceous limestone. In a general way it may be said that the lower and upper thirds of the formation contain 25 per cent...

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