The output will be about 30 tons of "clinker" ready to be ground into cement.
(It may be noted that here and generally in this article "burn" is used in the technical sense; it is technically correct to speak of cement clinker Surninq being "burned," although it is not a fuel; in accurate terms it is the fuel which is burned, and it is the heat it generates which raises the clinker to a high temperature, i.e.
_ rying space or urry Kiln Lower shaft containing hot clinker Grate.,› Upper shaft containing raw material FIG.
the burner where the temperature is highest, and is there heated so highly that the union of the lime, silica and alumina is complete, and fully burnt clinker falls out of the kiln.
Rotatory kilns of various other makes are now in use, but the same principles are embodied, namely, the employment of a rotating inclined cylinder for burning the raw materials, a burner fed with powdered coal and a blast of air, and some device such as a cooling cylinder or cooling tower by which the clinker may be cooled and the air correspondingly heated on its way to the burner.