Clinker is an artificial rock produced from limestone, clay and ferruginous additives.

These materials are ground together to obtain a precisely specific mixture, this homogeneous raw meal is heated in a rotary kiln up to 1450ºC to reach the sintering point.

Various types of kilns, using various processes are used, the biggest ones can produce up to 10.000 Mt/day.

Coming out of the kiln, the clinker is cooled down to about 100ºC and looks like round stones between 1 and 5cm in diameter of a dark gray color.

Clinker is composed by 4 majors oxides, i.e. calcium, silicium, aluminum and iron oxide. It is the basic material to obtain Portland Cement. It can be ground at the same factory where it was produced or it can be transported to another cement plant or grinding facility for transformation.