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NAVIGATION

Corporate Profile

Cement Facts

History of Cement
Cement Industry in Malaysia
Manufacture of Ordinary Portland Cement
Raw Materials Preparation
Raw Materials Proportioning & Grinding
Clinker Burning
Cement Grinding
Cement Storage & Despatch
Cement Quality

 

A brief history on cement

Cement of the Early Days
Cement can vaguely be defined as any compound that can be used to bind two materials together e.g. wood, bricks etc. Today the term is generally synonymous with Portland Cement, which is one of several types produced.
The first recorded use of cement was by the Egyptians, who used it to build their pyramids, about 5,000 years ago. The cement used during that period was made from lime and gypsum. In the later periods of civilization, volcanic materials were ground with lime and sand to produce a better cement. During the rise of the Roman Empire this "technology" spread throughout Europe. In December 1755 in Plymouth, England, a wooden lighthouse was razed to the ground. The job of rebuilding this lighthouse was given to John Smeaton. In an effort to construct a fire resistant building he experimented with many types of building materials, cement being one of the materials being studied. He discovered that siliceous limestone produced superior cement, he thus used limestone and volcanic lime to build the now famous "Eddystone Lighthouse". In 1818 Louis Joseph Vicat discovered that burnt clay when mixed with lime also resulted in cement. These were the first steps in the manufacture of Portland cement.

Development of the Cement Industry
In 1824 Joseph Aspidin mixed powdered limestone and clay with water and moulded them into slabs. These were then burned until carbon dioxide was liberated, he then ground the slabs into a fine powder. This cement when used gives a colour and strength similar to the stones from the island of Portland, hence the term Portland Cement.

20 years after this Isaac Charles Johnson ground half molten clinker from a kiln , he observed that the strength of this cement was slow to rise but ultimately produced a higher strength in the end. He then formulated the theory that to produce good cement the raw materials have to be burnt to a half molten state. Publication of his theory interested numerous cement manufacturers who concentrated in this method of production, which caused the quality of Portland cement to improve by leaps and bounds. In 1870 the quick setting of the cement was solved by W. Michaelis, who observed that addition of gypsum prolonged the setting time.

Development of the Kiln
Up to this point the lime components of the cement were burnt in shaft or ring kilns. These were originally used to burn quick lime and bricks respectively. In 1873, Ransom an English technician, invented the first rotary kiln, this was 18 inches in diameter and 12 feet long, which was not a success at all. He later increased the diameter to 2.5 feet and lengthened it to 18 feet, this was met with partial success. As with most things he eventually discarded the idea but gave the rights to an American company to continue further experiments. The experiments led to kilns that were some 260 feet long. It has been observed that successful rotary kilns require a diameter of greater than 3 meters, the kilns these days have diameters exceeding 4 meters and 80 meters in length. Prior to the dry process kilns the older kilns had diameters in excess of 6 meters and lengths of 170 meters. These dimensions have been reduced with the development of suspension pre-heaters.
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