Kilns

The cement kiln burns rawmix to produce clinker, which is then ground to make cement.

The cement kiln is the heart of the cement making process: this is today almost a cliché, but was not always quite so true. In the modern cement plant, the kiln is the most expensive and technically complex part of the plant, and because it must be run all the time (unlike other sections of the plant) it effectively defines the output capacity of the plant. It stands out also in that, unlike the other processes involved, the “pyroprocessing” stage of cement manufacture is absolutely unique to the industry, and has devoted to it a complex and specialized multi-disciplinary technology all its own.

Because of this, the cement kiln scarcely needs to be considered under the general category of “kilns”. In addition to its uniqueness, it also stands out among pyroprocessing equipment as by far the most economically significant world-wide. The blast furnace for iron production produces less than half the tonnage produced by cement kilns, although it runs ahead in terms of fuel usage. In terms of CO₂ production, Portland cement kilns – when using limestone as a raw material – are by far the largest industrial manufacturing source. The taming of these emissions is likely to further increase the sophistication of the kiln design.

It is for these reasons that the evolution of the cement kiln is the major preoccupation of this site. The following topics are discussed: