tribasic phosphoric acid reacts with calcium are three types of salts.This calcium hydrogen phosphate CaHPO4, calcium dihydrogen phosphate Ca (H2PO4) 2 and orthophosphate, or calcium phosphate, whose formula is given: Ca3 (PO4) 2.This salt is an inorganic substance, under standard conditions is a solid, and the liquid passes (melts) at a temperature of 1200 C. The density equal to 2.81 g / cm³, the molar mass - 310.2 g / mole.Calcium phosphate is poorly soluble in water at 20 C mass fraction did not exceed 0.0025%.Unlike most of the other compounds, the level of its solubility decreases with increasing temperature.Thus, in heating this salt is able to form deposits.
Calcium phosphate is a white crystalline substance, which is part of the mineral apatite (belongs to the class of phosphates containing up to 56% CaO, about 41% P2O5), phosphorite (fibrous or dense aggregates apatite containing more than 18% P2O5)and hydroxyapatite (the main component of bone tissue of humans and animals).Prove the origin of some deposits of feces or dead animals.Other fields (eg, in the ancient seas) formed as a result of life "fosforobaktery."But in some places the deposits of this mineral are purely mineral origin.All of them are widely distributed in nature and are used in the national economy.
Apatite is the raw material for phosphorus, phosphoric fertilizers and phosphoric acid, as well as applied in ferrous and non-ferrous metallurgy, production of glass and ceramics.Natural mineral phosphates are rocks of different origin, but more sedimentary, they are used for further enrichment and the production of phosphate fertilizers.Apatite and phosphorite reserves are of great importance for agriculture, as used not only to produce fertilizer, but also as a source of calcium for feeding birds or animals: fodder calcium phosphate produced in accordance with GOST 23999-80.
Mineral inorganic - apatite - is used in more than twenty manufacturing processes.Its use in the production of abrasives, glass and ceramics, as well as for producing free phosphoric acid and phosphorus.The process proceeds according to the scheme: 3SiO2 + Ca3 (PO4) 2 + 5C → 3CaSiO3 + 5CO + 2P.This substance is also claimed in the food industry: available as a food additive E341 according to GOST P 53945-2010, which, along with the 1- and 2-substituted salts of phosphoric acid include calcium phosphate.Production of this product involves strict requirements to the feedstock.In the production of food additives used phosphoric acid grade A GOST 10678-76, calcium hydroxide according to GOST 9262-77 and chemically precipitated chalk GOST 8253-79.
mineral containing calcium phosphate plays an important role in the human body.Hydroxyapatite can be represented by the formula 3Sa3 (PO4) 3 • Ca (OH) 2.It is the main component, and the building material of human bones.This mineral is a part of dental enamel in the form fluorapatite.The daily requirement for large and phosphorus is in the range from 800 to 1500 mg.During the metabolism of phosphorus compounds in the human body corresponds to the liver, and this process is regulated hormones and vitamin D. Miscellaneous diseases of bones and teeth are developed with a deficiency of phosphorus in the body.Calcium phosphate is supplied with food and strengthens bones and teeth, and in combination with other minerals supports the cardiovascular system, and prevents the occurrence of colon cancer, regulates the function of the nerves involved in the construction of collagen helps to reduce cholesterol.Phosphates are derived from feces and urine every day for around 4 g of salt of phosphoric acid.
main sources of calcium phosphate human - cow's milk and dairy products, cereals, fortified juices, cheese, goat's milk, salmon, sardines and anchovies.Being poorly soluble in water is calcium phosphate in a high concentration in the milk, since there is a colloidal system in the form of micelles - particles of very small insoluble core, which is surrounded by solvent molecules and adsorbed ions.Included in the milk casein rather, calcium caseinate, which relates to the phosphoproteins as it contains a phosphate group.However, experts recommend to avoid an excess of calcium phosphate, especially in the form of fortified foods or additives, if a person has either of the following diseases: parathyroid, kidney stones or during the ongoing treatment comprising tetracycline antibiotics.
