Most limestone is used in the construction industry principally as an aggregate and in the manufacture of cement. A high degree of chemical purity in these limestones is not usually necessary although some restrictions on contaminants may be made. Around 10 million tonnes of limestones are used annually for industrial purposes which require ‘high-purity’ limestone or limestones of specific physical properties which are, at least to some extent, related to the purity of the limestone. Such limestones are used in the iron and steel industry, in the chemicals industry, in glass making, in fillers and pigments and in a wide range of other industries. An increasingly important use of ‘high-purity’ limestone is in flue gas desulphurization schemes in power generation plants.
This paper describes the broad geological resources of high-purity limestone in England and Wales. Most high-purity deposits occur within the Carboniferous Limestone of the Peak District, the Mendips, South and North Wales, parts of the northern Pennines and around the fringes of the Lake District. Large areas of the Chalk outcrop also contain high-purity resources, particularly part of the Upper Chalk outcrop of southern England and in the Burnham and Welton chalk outcrops of northern England. The dolomites and dolomitic limestones of the Permian Magnesian Limestone also locally contain consistently pure deposits. Jurassic, Devonian and Silurian limestones are mainly of low chemical grade.