ABSTRACT
Portland cement is manufactured as follows. A calcareous material (limestone) and a siliceous material (clay, shale) are ground together, usually with the addition of an iron powder in certain proportions, to form a raw meal (for dry technology), or a slurry (wet technology), which is fed into a rotary kiln and calcined at temperatures up to 1450ºC. Partial melting occurs to form a clinker which is rapidly cooled. This can be stored before it is mixed with a certain amount of gypsum and interground. The nal product is called Portland cement.
