Finnsementti

Manufacture

Main stages of cement manufacture:

  • quarrying, crushing and raw grinding of limestone
  • sintering of Portland clinker
  • grinding of cement

Quarrying the limestoneThe main raw material in cement is Finnish limestone, which is quarried, crushed and sorted prior to raw grinding. In addition to calcium carbonate (CaCO3) that is attained from limestone, the manufacturing of cement requires silicon dioxide (SiO2), ferric oxide (Fe2O3) and aluminium oxide (AI2O3), which are attained from the surplus stone of limestone quarries and other industry by-products. The feeding ratios of raw materials are based on the chemical composition and the materials are fed into the raw grinding mill in which they are ground to a fine powder.

Producing cement clinkerCement clinker is produced in a 100-metre-long rotary kiln. The raw meal is fed into the rotary kiln through the cyclone tower where it is heated up by flue gases exiting the kiln. Calcium oxide, silicon, aluminium and iron compounds become calcium compounds and are sintered into cement clinker when the material’s temperature reaches +1400 °C. At the back end of the kiln the cement clinker is cooled quickly in air coolers to approximately 200 °C. At this point the clinker is reminiscent of coarse gravel.

Raw grindingCement is manufactured by grinding clinker, additives and gypsum in a ball mill. Finnsementti uses limestone and blast-furnace slag as additives. Gypsum is ground into the mixture to adjust the setting time of the cement. The properties of the cement are adjusted using the clinker’s composition, the relative portions of the additives and the fineness of the powder, among other things.

Finnsementti is the only Finnish manufacturer of cement. Harnessing our century-long experience, we produce consistently superior cement and create jobs within our industry. The majority of Finland’s cement demand is produced at Finnsementti’s plants in Pargas and Lappeenranta. In addition to cement, our offering includes various concrete admixtures, mineral additives and special aggregates.

Finnsementti Oy
P.O. Box 115
Lars Sonckin kaari 16
02601 Espoo, Finland
Tel. +358 (0)201 206 200
info@finnsementti.fi