Chalk natural, purified and dried, it has no chemical impurities. Saturated with calcium, it is useful for use in food. Hard, dense and crisp chalk. Crack with a crunch. It is very useful and tasty.
Chalk quarry association “Don soda.” Donetsk region;
Slavyansk, p. Andreevka;
Chalk (as chalk; n Kreide; f craie;…. And creta) – weakly, fine-grained carbonate rocks kind of white or yellowish color, consisting mainly of calcium carbonate of natural origin or obtained by artificial means. For natural chalk is characterized by the absence of recrystallization and lamination, a large number of moves of different animals iloyadnyh (gruntoedov).
Chalk consists of fragments of skeletons of multicellular organisms (10%), the shells of single-celled rhizopods – foraminifera (10%), rubble and limestone formations of microscopic algae coccolithophorids (30-40%), fine-grained crystalline calcite (40-50%) and insoluble minerals (2 -3%). Occasionally encountered Cretaceous mollusk shells, skeletons of bryozoans, sea urchins and lilies, siliceous sponges, corals, flint nodules, pyrite and phosphorite. The chemical composition of the Cretaceous deposits of various changes within the following limits (%): 47-55 CaO; 0,1-1,9 MgO; 0,2-6,0 SiO2; Al2O3 0.2-4.0; 0,02-0,7 Fe2O3 + FeO; 40-43 CO2. The density of 2690- 2720 kg / m3; a porosity of 44-50%; natural moisture content 19-33%. Chalk is a poluzatverdevshy yl warm seas, deposited at a depth of 30 to 500 m. It is widely distributed in nature and is characteristic of the upper part of the Cretaceous and Lower Paleogene deposits, due to the development of lush coccolithophorids. The most significant band of Cretaceous sediments is common in Europe, from the Emba River in West Kazahstanedo UK. Their power reaches several hundred meters (in Kharkiv region – 600 m). In terms of physical properties and structural features of chalk are three varieties: white writing; marly, wherein a higher density and lower white, due to the presence of clay materials; chalk-like limestone – transition from the Cretaceous to the difference between the limestone.
The national economy chalk used for the production of lime, cement, soda, glass, school chalk. Applied as a filler for rubber, plastics, paper, paints and varnishes. In agriculture goes to liming and fertilization of animals, perfumes – for the preparation of toothpastes and powders.
chalk quality is mainly determined by its chemical composition, and for many industries regulated by the state and industry standards; GOST 17498-72 “Chalk Lines brand, the basic technical requirements.”; GOST 12085-73 “Chalk natural enriched (used in rubber, cable, paint and plastics industry)”; GOST 8253-79 “Chalk, precipitated”; OCT 21-37-78 “chalk and limestone for mineral feeding livestock and poultry” and others. The suitability of chalk for the production of lime and cement semi-works is determined by tests. On January 1, 1985 to take into account 219 CCCP chalk with balance reserves deposits explored by industrial categories, 1680000000. M. In addition, 31 chalk deposit with reserves of 3.534 billion. M accounted for in the balance sheet reserves of cement raw materials. Stocks chalk up 12% of total reserves of carbonate cement resources. Stocks of the largest Sebryakovsky (Volgograd region of the RSFSR) deposits of chalk for cement production 890 million. M. The deposits of chalk with reserves of 20 million. Tons or more are considered large. Large reserves of chalk have France, the United Kingdom, the German Democratic Republic, Denmark. In 1984 in CCCP 75 developed fields (all open pit) and produced 12.4 million tons.; In addition, 39.2 million. tons produced by 17 cement raw material deposits. Zhiguli Building Materials Plant (Kuibyshev region of the RSFSR) of limestone artificially receives chemically besieged chalk in an amount of 16 500 tonnes per year. In the US, there are only chalk deposits in the central and southern states, but the poor quality of chalk, so the United States imported high-grade chalk from France, the UK and Denmark.