Cement clinker

タイトルまたは説明

Clinker is a nodular material produced in the kilning stage during the production of cement and is used as the binder in many cement products. The lumps or nodules of clinker are usually of diameter ***5 mm and dark grey in color.

It is produced by heating limestone and clay to the point of liquefaction at about ***0°C****0°C in the rotary kiln. Clinker, when added with gypsum (to control the setting properties of cement and ensure compressive strength) and ground finely, produces cement.

Clinker can be stored for long periods of time in a dry condition without degradation of quality, hence it is traded internationally and used by cement manufacturers when raw materials are found to be scarce or unavailable.

The composition of clinker is examined by two separate approaches:

1. mineralogical analysis, using petrographic microscopy and/or x-ray diffraction analysis
2. chemical analysis, most accurately by x-ray fluorescence spectrometry

The four main components of clinker are:

• Alite: approximately tricalcium silicate (typically about *5% of the total)
• Belite: approximately dicalcium silicate (typically about *5% of the total)
• Aluminate: very approximately tricalcium aluminate (typically about 7% of the total)
• Ferrite: very approximately tetracalcium aluminoferrite (typically about 8% of the total)