Portland cement clinker quantity

Portland cement clinker potential phase composition is presented in Table 4. It could be seen that the C3A content in the clinker was 9.46% which is important for the cement hydration rate and cement sulfate resistance. Common Portland cement is not resistant to the sulfate influence because of the significant C3A content, whose hydrates react with sulfate ions resulting in expansive compounds. Portland cement with the higher resistance to sulfates must have low C3A content. Moderate to high content of mineral alite - C3S (54.72%) is usual for the Serbian cement plants and enables the addition of higher quantities of mineral admixtures without influencing the quality of final cement. 

The cement type manufactured in the largest quantities and used most is Portland cement . It consists of so-called Portland cement clinkers admixed with gypsum or anhydrite. 

The required quantity of dry raw material (i.e., without its inherent natural moisture) for the production of Portland cement clinker can be computed as... 

A quantity of sulphate (in the form of gypsum or a mixture of gypsum and anhydrite-II) is always added to the Portland cement clinker in the finish grinding... 

Portland cement also consumes large quantities of gypsum. About 5% of gypsum is added to the cement clinker before grinding. Addition of gypsum aids in increasing the early strength of the cement and prevents undesirable false set. 

Portland cement was invented in 1824. The raw materials used in its manufacture are limestone, quartz sand, clay and iron ore. These supply the necessary ingredients lime, silica, alumina, and iron. Properly proportioned quantities of the raw materials are pulverized and fired to result in cement clinkers. These are finely ground and mixed with up to five percent gypsum to make the finished product. Thousands of tons are produced annually in the USA. A small percentage of this total is used for grouting. 

The composition of calcium aluminate ferrite (the ferrite phase) in Portland cements may vary between about C2(Aq Fq 3) and C2(A3, Fg and thus it may be best expressed by the formula C2(A, F), even though the formula C4AF is also used occasionally. On the nanometer scale the stmcture of this phase consists of Ca ions, each of them surroimded by seven oxygen neighbors, combined with AP" and Fe ions distributed between octahedral and tetrahedral sites. In industrial clinkers the ferrite phase may also contain significant quantities of foreign ions the Fe is partly substituted by Mg and equal... 

Cement is made by heating limestone (ealeium earbonate) with small quantities of other materials (sueh as clay) to 1450°C in a kiln, in a process known as calcination, whereby a molecule of carbon dioxide is liberated from the calcium carbonate to form calcium oxide, or quicklime, which is then blended with the other materials that have been included in the mix. The resulting hard substance, called clinker , is then ground with a small amount of gypsum into a powder to make Ordinary Portland Cement , the most eommonly used type of cement (often referred to as OPC). 

Portland cement is fabricated by heating limestone with small quantities of materials carrying silica and alumina (such as clay) to about 1500°C in a rotary kiln this process is known as calcination. The resultant hard, sintered clinker is then ground together with a small amount of gypsum (ca. 3%) into a fine powder to produce so-called Ordinary Portland Cement (OPC), the most commonly used type of cement. 

The use of g3 sum to control setting in Portland cement accounts for considerable quantities of the use of this material.1 Control of the reaction rate of tricalcium aluminate (C3A),the constituent of cement that reacts most rapidly with water, is most commonly achieved through the addition of gypsum (sometimes hemihydrate is also used) to commercial Portland cement. This material is normally added to the cement clinker (in amounts of approximately 2 to 3%) before grinding. The cement manufacturers usually specify a sulfurtrioxide content of about 36%. Excess sulfate in the form of hemihydrate can cause flash set in portland cement. 

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