Bulletin - United States Geological Survey, Issue 243

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Page 22 - ... 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 importance to be allowable to not exceeding 2 per cent of the...
Page 11 - The object lias been to treat the subject from the geological rather than the technical standpoint, although the technology of cement manufacture is also discussed with sufficient fullness for the purpose of the report.
Page 334 - ... (2) Natural cements, after burning and grinding, are usually yellow to brown in color and light in weight, their specific gravity being about 2.7 to...
Page 22 - 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...
Page 56 - ... per cent. of lime. With equal lime percentages, the cement carrying high silica and low alumina and iron will require a higher temperature than if it were lower in silica and higher in alumina and iron. But, on the other hand, if the alumina and iron are carried too high, the clinker will ball up in the kiln, forming sticky and unmanageable masses. Character of kiln coal. — The fuel most commonly used in modern rotary kiln practice is bituminous coal, pulverized very finely. Coal for this purpose...
Page 363 - it is attackable by weak acids and also by alkalies. It combines particularly with hydrated lime in setting, and gives rise to silicates and aluminates of lime identical with those which are formed, by entirely different reactions, during the setting of Portland cement. It is upon this property that the manufacture of slag cements, which assumes daily greater importance, is based.
Page 42 - ... ton or cubic yard of raw material, and this is the method followed by quarrymen or miners in general. To the cement manufacturer, however, such an estimate is not so suitable as one based on the cost of raw materials per ton or barrel of finished cement.
Page 48 - ... heated by waste kiln gases, in which the temperature is sufficient not only to dry the mixture, but also to partly powder it and to reduce most of the limestone to quicklime. The mixture is then pulverized and fed into rotary kilns. Of the three general processes above described, the second is unsuited to American conditions. The first and third are adapted to the use of the rotary kiln. The third seems to be the most economical, and has given a remarkably low fuel consumption in practice, but...
Page 335 - York, could be replaced by an equal amount of lime carbonate and the burnt stone would still give a hydraulic product. If, however, the clayey portion (silica, alumina, and iron oxide) of the Rosendale rock could be removed, leaving only the magnesium and lime carbonates, the burnt rock would lose all of its hydraulic properties and would yield simply a magnesian lime. This point has been emphasized because many writers on the subject have either explicitly stated or implied that it is the magnesian...
Page 54 - ... the destructive action of the molten clinker. The cement mixture is fed in at the upper end of the kiln, while fuel (which may be either powdered coal, oil, or gas), is injected at its lower end. The kiln, which rests upon geared bearings, is slowly revolved about its axis.

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