Question

What is the approximate composition of Portland cement? What raw materials are used in the manufacture of this cement? Describe method.

Answer 1

Portland cement is nothing but the common type of cement in general use as basic ingredient of concrete, mortar etcThus, answer to this question includes the fact that it is similar to normal cement composition which includes limestone and gypsum.

Complete answer:
We have studied about basic cement composition and its synthesis in the lower chemistry classes. Portland cement is the generic term used in virtually all concrete.
Portland cement consists mainly of compounds of lime mixed with silica and alumina. Typical composition of Portland cement is as follows:
$CaO\to 50-60$
$Si{{O}_{2}}\to 20-25$
$A{{l}_{2}}{{O}_{3}}\to 5-10$
$F{{e}_{2}}{{O}_{3}}\to 1-2$
$MgO\to 2-3$
$S{{O}_{3}}\to 1-2$
It also has few amounts of oxides of iron, magnesium and sulphur.
-The method of preparation of Portland cement involves high temperature.
-Initially, clay, shale and limestone is ground well to form powder and then baked in a kiln of temperature above 600$^{o}C$ and then fusion temperature which is about1450$^{o}C$.
-This forms cement clinkers which are then mixed with gypsum to get the cement.
- There are also several types of Portland cement depending upon the method of production among which the above described method is more commonly used.
- Portland cements are also used for emergency construction and repairs and construction of machine bases and gate installations.

Additional information:
Portland cement’s name is derived from its resemblance to Portland stone which was quarried on the isle of Portland in England named by Joseph Aspdin who obtained a patent in 1824.

Note:
Portland cement is most commonly called as Type IV Portland cement which is generally known for its low heat of hydration. Do not confuse that Portland cement and cement are completely different.