What is Clinker?

Portland cement clinker is a dark grey nodular material made by heating ground limestone and clay at a temperature of about 1400 °C – 1500 °C.

The nodules are ground up to a fine powder to produce cement, with a small amount of gypsum added to control the setting properties.

Nodules range in size from 1mm to 25mm or more and are composed mainly of calcium silicates, typically 70%-80%. The strength of concrete is mainly due to the reaction of these calcium silicates with water.


Caprina LLC is one of the most prominent exporters in the field of different types of cement and clinkers, it set out to begin its business as a commercial and marketing Iranian corporation.

Throughout the year, this business is trying to provide all products needed by its customers, including importers, wholesalers, chain stores, and domestic and international food factories.

Composition of Clinker

The composition of clinker is examined by two separate approaches:

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

Composition of Clinker

Portland cement clinker contains four principal minerals:

•Alite: approximately tricalcium silicate (typically about 6

5% of the total)
•Belite: approximately dicalcium silicate (typically about 15% 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)

Other substances may be present in small amounts

Salt phases – various combinations of sodium, potassium and calcium cations with sulfate and chloride anions, such as:

•Arcanite – K2SO4
•Calcium Langbeinite – K2Ca2(SO4)3
•Aphthitalite – K3Na(SO4)2
•Sylvite – KCl

Other substances may be present in small amounts

Low-temperature phases – various intermediate chemical species that have escaped further thermal processing, such as:

•Spurrite – Ca5(SiO4)2(CO3)
•Ternesite – Ca5(SiO4)2(SO4)
•Ellestadite – Ca10(SiO4)3(SO4)3(OH)2
•Ye’elimite – Ca4(AlO2)6(SO4)

Other substances may be present in small amounts


Portland cement clinker is ground to a fine powder and used as the binder in many cement products. A little gypsum is sometimes added. It may also be combined with other active ingredients or chemical admixtures to produce other types of cement including:

ground granulated blast furnace slag cement

pozzolana cement

silica fume cement

Clinker, if stored in dry conditions, can be kept for several months without appreciable loss of quality.

Because of this, and because it can easily be handled by ordinary mineral handling equipment, clinker is traded internationally in large quantities. Cement manufacturers purchasing clinker usually grind it as an addition to their own clinker at their cement plants.

Manufacturers also ship clinker to grinding plants in areas where cement-making raw materials are not available.

Cement and clinker are not the same material.

Cement is a binding material used in construction whereas clinker is primarily used to produce cement.

The main differences between clinker and cement are given below.

Difference between Clinker and Cement

Clinker Cement
1 Clinker is a nodular material which is used as the binder in cement products. Cement is a binding agent that sets and hardens to adhere to building units such as stones, bricks, tiles etc.
2 Clinker is a granular substance containing spherical pellets of diameter 3-25 mm. Cement is such a fine powdery substance that each pound of cement contains 150 billion grains.
3 Clinker is a granular substance containing spherical pellets of diameter 3-25 mm. Cement is such a fine powdery substance that each pound of cement contains 150 billion grains.
4 Clinker is produced inside the kiln during the cement manufacturing process. Raw mix is heated and then rapidly cooled to produce the marble-sized pellets of clinker. Cement is produced by grinding clinker (added with different active ingredients to achieve the desired properties of cement) into a fine powder.
5 The composition of a typical good quality clinker for general use: 37-72% of 3CaO.SiO2; 6-47% 2CaO.SiO2; 2-20% 2CaO.Al2O3; 2-19% 4CaO. Al2O3.Fe2O3 Composition of the most common type of cement: 85% clinker, 1.5-3.5% gypsum by SO3 content, and up to 15% admixtures.
6 The primary use of clinker is to manufacture cement. Cement is used in construction to make concrete as well as mortar and to secure the infrastructure by binding the building blocks. It is also used for water-proofing, filling or sealing gaps, and making decorative patterns.

Types of Clinker

Types of Clinker

The most common type of clinker is produced for Portland cement and its blends. The types of clinker vary depending on the type of cement for which the clinker is produced. Aside from the Portland cement blends, some special types of cement clinker are listed below:

1.Sulfate Resistant Clinker
2.Low Heat Clinker
3.White Clinker
4.Low-alkali Clinker
5.Belite Calciumsulfoaluminate Ternesite (BCT)

1. Sulfate Resistant Clinker

It contains 76% alite, 5% belite, 2% tricalcium aluminate, 16 % tetracalcium aluminoferrite, and 1% free calcium oxide.

Its production has decreased in recent years because sulfate resistance can easily be obtained by using granulated blast furnace slag in cement production.

2. Low Heat Clinker

It contains 29% alite, 54% belite, 2% tricalcium aluminate and 15 % tetracalcium aluminoferrite, with very little free lime.

It is no longer produced because cement produced from ordinary clinker and ground granulated blast furnace slag has excellent low heat properties.

3. White Clinker

It contains 76% alite, 15% belite, 7% tricalcium aluminate, no tetracalcium aluminoferrite, and 2% free lime, but the composition may vary widely.

White clinker produces white cement which is used for aesthetic purposes in construction.

The majority of white cement goes into factory-made pre-cast concrete applications.

4. Low-alkali Clinker

Reduction of alkali content in clinker is done by either replacing the raw-mix alumina source with another component (thus obtaining a more expensive material from a more distant source),

or installing an “alkali bleed”, which involves removing some of the kiln system’s high temperature gases (which contain the alkalis as fume), resulting in some heat wastage.

5. Belite Calciumsulfoaliminate Ternesite (BCT)

This concept is used in producing a type of clinker with up to 30% less carbon dioxide emission.

Energy efficiency improves and the electricity costs for the manufacturing process are about 15% lower as well.

Types of Clinker

How to export Clinker

We can organize the transport to the ideal port for loading or onward transit.

Also we offer dynamic international freight forwarding and logistics packages for our customers, whether it is

a road or rail freight,

air or ocean cargo.

How to export Clinker How to export Clinker