Use of Limestone in Cement Production

In many countries, cement production represents the second largest outlet for limestone and is exceeded only by the use of limestone for aggregate in construction and building. The world production of Portland cement is in the order of 1420 million tonnes per year [9.1]. The amount of limestone required varies with the grade of cement and the raw materials used, but is estimated to be approximately 1.0 tonne per tonne of cement. Thus the global cement industry uses roughly 1,400 million tonnes per year of limestone, or about 32 % of the extracted limestone. 

Many lime producers make Portland cement as a co-product to maximise the use of a limestone deposit and minimise tipping of low grade material. For this reason, and because cement is such an important user of limestone, the process of cement production is described briefly in this chapter. 

Portland limestone cements are a relatively recent development. They consist of intimate blends of Portland cement and limestone, in which the limestone acts as an extender [9.2, 9.3]. About 1 million tonnes of limestone was used in 1990 in this application in the European Union [9.1], and, following the publication of a European Prestandard for the product in 1992 [9.2], the amount is likely to grow rapidly. 

Masonry cement [9.4, 9.5] is a traditional product which consists of Portland cement as the primary strength-developing constituent and an inorganic component which may be ground limestone. 

High-alumina cement is produced by reacting limestone with bauxite. The use of limestone for this process is in the order of 250,000 tonnes per year. 

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