54. Limestone (l, ll)

Limestone should meet the following requirements:

a) the content of calcium oxide (CaO) calculating the amount of calcium carbonate (CaCO3), the contents of which should be less than 75%;

b) the clay content is determined methylene solution in accordance with EN 933-9 and should not exceed 1.20 g / 100 g To test lime must be ground to a fineness of about 5,000 cm2 / g. Specific surface area is determined in accordance with EN 196-6.

c) the total organic carbon (TOC) for the EN 13639 test methods shall comply with one of the following criteria:

- LL: not exceed the mass fraction of 0.20%;

- L: must not exceed the mass fraction of 0.50%.

     Izvestnyak- widespread monomineral rock composed of calcite; it can be easily determined by a violent reaction with hydrochloric acid. Due to the wide distribution, ease of handling and chemical properties of limestone is mined and used to a greater extent than other species, second only to the sand and gravel deposits. The limestones are of different colors, including black, but the most common breed of white, gray or have a brownish tint. The bulk density of 2.2-2.7. This soft rock, easy to scratch the knife blade. Limestone effervesce rapidly by reaction with a dilute acid. In accordance with its sedimentary origin has a layered structure. Net Limestone consists of calcite (rarely with a low content of other forms of calcium carbonate - aragonite). Present and impurities. The limestones are found in almost all continents except Australia. They were formed in different geological epochs. Seam Thickness varies from a few centimeters to hundreds of meters. The limestones are common in the United States and take up 75% of the country. In Russia, the limestone common in the central regions of the European part of, as well as common in the Caucasus, the Urals and Siberia. Limestone (in the broadest sense) have an extremely diverse range of applications. They are used in the form of lump limestone, crushed stone, piece (Saw, wall) and quarry stone, facing slabs, mineral crumbs, crushed sand, mineral powder, mineral wool, limestone powder. The main consumers - the cement industry (limestone, chalk, marl), construction (obtaining building lime, concrete, plaster, mortar, masonry walls and foundations; decorative-facing work, etc.), road and rail construction, rock placement for coastal protection and waterworks, metallurgy (limestone and dolomite - fluxes and refractories processing nepheline ore into alumina, cement and soda), agriculture (limestone flour in farming practices and animal husbandry), oil and coke, food (especially sugar), pulp and Paper, glass (limestone, chalk, dolomite), leather (limestone), rubber, cable, paint and varnish industry (chalk as a filler). Other areas of application - polishing products, non-ferrous metals and nacre (limestone), electric welding (chalk to cover the electrodes), writing chalk (chalk), insulation of building structures and technological equipment (mineral wool), etc.