Calcium carbonate, white chalk (E170). Chalk (calcium carbonate) CaCo3 Calcium carbonate formula

The article describes a food additive (anti-caking agent and anti-caking agent, dye, stabilizer) calcium carbonate (E170, calcium carbonate), its use, effects on the body, harm and benefits, composition, consumer reviews
Other additive names: calcium carbonates, chalk, E170, E-170, E-170

Functions performed

anti-caking agent and anti-clotting agent, dye, stabilizer

Legality of use

Ukraine EU Russia

Calcium carbonate, E170 - what is it?

Calcium carbonate is a very common chemical compound in nature. Food additive E170 is a well-known chalk, purified from accompanying impurities. The chemical formula of calcium carbonate is CaCO 3 .

The concept of food additive E170 combines:

• calcium carbonate E170i;
• calcium bicarbonate E170ii.

The industrial production of calcium carbonate consists in the extraction and purification of raw materials contained in such natural minerals as vaterite, aragonite and calcite. Calcium carbonate is the main component of marble, limestone, travertine and chalk. In food production, grades of calcium carbonate of the highest quality are used. The minimum amount of impurities is contained in the additive E170, obtained from marble.

Commercial calcium carbonate is sold in the form of a white, tasteless and odorless fine powder. It does not dissolve in water. Various forms of calcium carbonate are the "building material" for the shells of some sea creatures (mollusks, sponges), as well as the shells of chicken eggs.

Calcium carbonate, E170 - effect on the body, harm or benefit?

Calcium carbonate is harmless to health. Moreover, it is used in medicine as part of drugs that help compensate for the lack of calcium in the body. Additive E170 is very important for maintaining the vital activity of the human body. Calcium carbonate stabilizes blood pressure, takes part in the processes of maintaining the normal functioning of the heart, blood clotting, bone formation, and also significantly affects many other internal processes.

Food additive E170, calcium carbonate - use in food

Additive E170 is used in the food industry and in medicine. Its main functions in food products are: natural white food coloring, baking powder, acidity regulator, anti-caking and clumping agent, filler. Calcium carbonate is used in the production of certain types of cheese, condensed milk and cream, cocoa powder, chocolate, grape juice, baby food, etc.

Calcium is an element of the main subgroup of the second group, the fourth period of the periodic system of chemical elements of D. I. Mendeleev, with atomic number 20. It is denoted by the symbol Ca (lat. Calcium). The simple substance calcium (CAS number: 7440-70-2) is a soft, reactive, silver-white alkaline earth metal.

History and origin of the name

The name of the element comes from lat. calx (in the genitive case calcis) - "lime", "soft stone". It was proposed by the English chemist Humphrey Davy, who in 1808 isolated calcium metal by the electrolytic method. Davy electrolyzed a mixture of wet slaked lime with mercury oxide HgO on a platinum plate, which was the anode. A platinum wire immersed in liquid mercury served as the cathode. As a result of electrolysis, calcium amalgam was obtained. Having driven away mercury from it, Davy received a metal called calcium.

Calcium compounds - limestone, marble, gypsum (as well as lime - a product of burning limestone) have been used in construction for several millennia ago. Until the end of the 18th century, chemists considered lime to be a simple body. In 1789, A. Lavoisier suggested that lime, magnesia, barite, alumina and silica are complex substances.

Due to the high chemical activity of calcium in the free form in nature is not found.

Calcium accounts for 3.38% of the mass of the earth's crust (5th place in abundance after oxygen, silicon, aluminum and iron). The content of the element in sea water is 400 mg / l

isotopes

Calcium occurs in nature in the form of a mixture of six isotopes: 40Ca, 42Ca, 43Ca, 44Ca, 46Ca and 48Ca, among which the most common - 40Ca - is 96.97%.

Of the six naturally occurring calcium isotopes, five are stable. The sixth 48Ca isotope, the heaviest of the six and very rare (its isotopic abundance is only 0.187%), was recently discovered to undergo double beta decay with a half-life of 5.3×1019 years.

In rocks and minerals

Most calcium is contained in the composition of silicates and aluminosilicates of various rocks (granites, gneisses, etc.), especially in feldspar - anorthite Ca.

In the form of sedimentary rocks, calcium compounds are represented by chalk and limestone, consisting mainly of the mineral calcite (CaCO3). The crystalline form of calcite, marble, is much less common in nature.

Calcium minerals such as calcite CaCO3, anhydrite CaSO4, alabaster CaSO4 0.5H2O and gypsum CaSO4 2H2O, fluorite CaF2, apatites Ca5(PO4)3(F,Cl,OH), dolomite MgCO3 CaCO3 are quite widespread. The presence of calcium and magnesium salts in natural water determines its hardness.

Calcium, which migrates vigorously in the earth's crust and accumulates in various geochemical systems, forms 385 minerals (fourth in terms of the number of minerals).

Migration in the earth's crust

In the natural migration of calcium, a significant role is played by the “carbonate equilibrium”, associated with the reversible reaction of the interaction of calcium carbonate with water and carbon dioxide with the formation of soluble bicarbonate:

CaCO3 + H2O + CO2 ↔ Ca (HCO3)2 ↔ Ca2+ + 2HCO3−

(the equilibrium shifts to the left or right depending on the concentration of carbon dioxide).

Biogenic migration plays an important role.

In the biosphere

Calcium compounds are found in almost all animal and plant tissues. A significant amount of calcium is part of living organisms. So, hydroxyapatite Ca5(PO4)3OH, or, in another way, 3Ca3(PO4)2·Ca(OH)2 is the basis of the bone tissue of vertebrates, including humans; shells and shells of many invertebrates, egg shells, etc. are composed of calcium carbonate CaCO3. In living tissues of humans and animals, 1.4-2% Ca (by mass fraction); in a human body weighing 70 kg, the calcium content is about 1.7 kg (mainly in the composition of the intercellular substance of bone tissue).

Receipt

Free metallic calcium is obtained by electrolysis of a melt consisting of CaCl2 (75–80%) and KCl or from CaCl2 and CaF2, as well as by aluminothermic reduction of CaO at 1170–1200 °C:

4CaO + 2Al = CaAl2O4 + 3Ca.

Aluminothermy (aluminothermy; from lat. aluminum and Greek. therme - heat, heat) - a method of obtaining metals, non-metals (as well as alloys) by reducing their oxides with metallic aluminum.

Physical properties

Calcium metal exists in two allotropic modifications (allotropy (from other Greek αλλος - “other”, τροπος - “turn, property”) - the existence of the same chemical element in the form of two or more simple substances, different in structure and properties: the so-called allotropic modifications or allotropic forms.). Up to 443 °C, α-Ca with a cubic face-centered lattice is stable (parameter a = 0.558 nm), above β-Ca is stable with a cubic body-centered lattice of the α-Fe type (parameter a = 0.448 nm). The standard enthalpy ΔH0 of the α → β transition is 0.93 kJ/mol.

With a gradual increase in pressure, it begins to show the properties of a semiconductor, but does not become a semiconductor in the full sense of the word (it is no longer a metal either). With a further increase in pressure, it returns to the metallic state and begins to exhibit superconducting properties (the superconductivity temperature is six times higher than that of mercury, and far exceeds all other elements in conductivity). The unique behavior of calcium is similar in many ways to strontium (i.e. parallels in the periodic table are preserved).

Chemical properties

Calcium is a typical alkaline earth metal. The chemical activity of calcium is high, but lower than that of all other alkaline earth metals. It easily reacts with oxygen, carbon dioxide and moisture in the air, which is why the surface of calcium metal is usually dull gray, so calcium is usually stored in the laboratory, like other alkaline earth metals, in a tightly closed jar under a layer of kerosene or liquid paraffin.

In the series of standard potentials, calcium is located to the left of hydrogen. The standard electrode potential of the Ca2+/Ca0 pair is −2.84 V, so that calcium actively reacts with water, but without ignition:

Ca + 2H2O \u003d Ca (OH) 2 + H2 + Q.

With active non-metals (oxygen, chlorine, bromine), calcium reacts under normal conditions:

2Ca + O2 = 2CaO

Ca + Br2 = CaBr2.

When heated in air or oxygen, calcium ignites. With less active non-metals (hydrogen, boron, carbon, silicon, nitrogen, phosphorus and others), calcium interacts when heated, for example:

Ca + H2 = CaH2, Ca + 6B = CaB6,

3Ca + N2 = Ca3N2, Ca + 2C = CaC2,

3Ca + 2P = Ca3P2 (calcium phosphide), calcium phosphides of CaP and CaP5 compositions are also known;

2Ca + Si = Ca2Si (calcium silicide), calcium silicides of compositions CaSi, Ca3Si4 and CaSi2 are also known.

The course of the above reactions, as a rule, is accompanied by the release of a large amount of heat (that is, these reactions are exothermic). In all compounds with non-metals, the oxidation state of calcium is +2. Most of the calcium compounds with non-metals are easily decomposed by water, for example:

CaH2 + 2H2O \u003d Ca (OH) 2 + 2H2,

Ca3N2 + 3H2O = 3Ca(OH)2 + 2NH3.

The Ca2+ ion is colorless. When soluble calcium salts are added to the flame, the flame turns brick red.

Calcium salts such as CaCl2 chloride, CaBr2 bromide, CaI2 iodide and Ca(NO3)2 nitrate are highly soluble in water. CaF2 fluoride, CaCO3 carbonate, CaSO4 sulfate, Ca3(PO4)2 orthophosphate, CaC2O4 oxalate and some others are insoluble in water.

Of great importance is the fact that, unlike calcium carbonate CaCO3, acidic calcium carbonate (hydrocarbonate) Ca(HCO3)2 is soluble in water. In nature, this leads to the following processes. When cold rain or river water, saturated with carbon dioxide, penetrates underground and falls on limestones, their dissolution is observed:

CaCO3 + CO2 + H2O \u003d Ca (HCO3) 2.

In the same places where water saturated with calcium bicarbonate comes to the surface of the earth and is heated by the sun's rays, the reverse reaction occurs:

Ca (HCO3) 2 \u003d CaCO3 + CO2 + H2O.

So in nature there is a transfer of large masses of substances. As a result, huge gaps can form underground, and beautiful stone "icicles" - stalactites and stalagmites - form in the caves.

The presence of dissolved calcium bicarbonate in water largely determines the temporary hardness of water. It is called temporary because when boiling water, the bicarbonate decomposes, and CaCO3 precipitates. This phenomenon leads, for example, to the fact that scale forms in the kettle over time.

Calcium carbonate

Calcium carbonate (chalk, calcium carbonate, limestone) is an inorganic chemical compound, a salt of carbonic acid and calcium. Chemical formula - . In nature, it occurs in the form of minerals - calcite, aragonite and vaterite. Calcium carbonate is the main constituent of limestone, chalk and marble. Insoluble in water and ethanol.

Registered as white food coloring (E170).

Used as white food coloring E170. In the form of calcium carbonate, chalk is used for writing on boards. It is used in everyday life for a variety of purposes: for whitewashing ceilings, painting tree trunks, for alkalizing soil in gardening.

Purified from impurities, calcium carbonate is widely used in the paper and food industries, in the production of plastics, paints, rubber, household chemicals, and in construction. Paper manufacturers use calcium carbonate simultaneously as a bleach, filler (replacing expensive fibers and dyes), and deoxidizer. Manufacturers of glassware, bottles, fiberglass use calcium carbonate in large quantities as a source of calcium - one of the main elements needed for glass production. It is widely used in the manufacture of personal care products (such as toothpaste), and even in the medical industry. In the food industry, it is often used as an anti-caking agent and separator in dried dairy products. When used in excess of the recommended dose (1.5 g per day), it can cause milk-alkaline syndrome (Burnett's syndrome). Recommended for diseases of bone tissue.

Plastics manufacturers are one of the main consumers of calcium carbonate (more than 50% of total consumption). Used as a filler and dye, calcium carbonate is needed in the production of polyvinyl chloride (PVC), polyester fibers (crimplen, lavsan, etc.), polyolefins. Products from these types of plastics are ubiquitous - these are pipes, plumbing, tiles, tiles, linoleum, carpets, etc. Calcium carbonate makes up about 20% of the coloring pigment used in the manufacture of paints.

The vast majority of calcium carbonate extracted from minerals is used in industry. Pure calcium carbonate (eg for food or pharmaceutical use) can be made from a pure source (usually marble).

Alternatively, calcium carbonate can be prepared by calcining calcium oxide. Water is added to this oxide to give calcium hydroxide, and then carbon dioxide is passed through this solution to precipitate the desired calcium carbonate.

Applications of metallic calcium

The main use of calcium metal is as a reducing agent in the production of metals, especially nickel, copper and stainless steel. Calcium and its hydride are also used to obtain hard-to-recover metals such as chromium, thorium and uranium. Alloys of calcium with lead are used in batteries and bearing alloys. Calcium granules are also used to remove traces of air from electrovacuum devices.

Alloying

Pure calcium is used to alloy lead, which is used for the manufacture of battery plates, maintenance-free starter lead-acid batteries with low self-discharge. Also, metallic calcium is used for the production of high-quality calcium babbits BKA.

Nuclear fusion

The 48Ca isotope is the most efficient and widely used material for the production of superheavy elements and the discovery of new elements in the periodic table. For example, in the case of using 48Ca ions to produce superheavy elements in accelerators, the nuclei of these elements are formed hundreds and thousands of times more efficiently than when using other "projectiles" (ions).

The use of calcium compounds

calcium hydride

Calcium hydride is a complex inorganic substance with the chemical formula CaH2.

White. Decomposes when melted. Sensitive to atmospheric oxygen. Strong reducing agent, reacts with water, acids. It is used as a solid source of hydrogen (1 kg of CaH2 gives 1,000 liters of H2), a desiccant for gases and liquids, an analytical reagent for the quantitative determination of water in crystalline hydrates.

By heating calcium in a hydrogen atmosphere, CaH2 (calcium hydride) is obtained, which is used in metallurgy (metallothermy) and in the production of hydrogen in the field.

Optical and laser materials

Calcium fluoride (fluorite) is used in the form of single crystals in optics (astronomical objectives, lenses, prisms) and as a laser material. Calcium tungstate (scheelite) in the form of single crystals is used in laser technology, and also as a scintillator.

calcium acetate

Calcium acetate is the calcium salt of acetic acid. A colorless crystalline substance that is highly soluble in water. Formula (CH3COO) 2Ca

In the laboratory, it is obtained by the action of acetic acid on calcium carbonate until the evolution of gas ceases.

2CH3COOH+CaCO3→(CH3COO)2Ca+H2O+CO2Used in the laboratory to produce dimethyl ketone (acetone). This reaction is carried out by heating the calcium acetate.

(CH3COO)2Ca→CH3C(O)CH3+CaCO3

Calcium acetate is registered in the food industry as a food additive E263

calcium sulfide

Calcium sulfide is an inorganic binary chemical compound with the formula CaS.

Known mineral Oldhamite (eng. Oldhamite) consisting of calcium sulfide with impurities of magnesium, sodium, iron, copper. The crystals are pale brown to dark brown.

Physical properties

White crystals, cubic face-centered lattice of NaCl type (a=0.6008 nm). Decomposes when melted. In the crystal, each S2− ion is surrounded by an octahedron consisting of six Ca2+ ions, while each Ca2+ ion is surrounded by six S2− ions.

Slightly soluble in cold water, does not form crystalline hydrates. Like many other sulfides, calcium sulfide undergoes hydrolysis in the presence of water and smells like hydrogen sulfide.

It is used for the preparation of phosphors, as well as in the leather industry to remove hair from hides, and is also used in the medical industry as a homeopathic remedy.

calcium carbide

Calcium carbide CaC2 is widely used to obtain acetylene and to reduce metals, as well as in the production of calcium cyanamide (by heating calcium carbide in nitrogen at 1200 ° C, the reaction is exothermic, carried out in cyanamide furnaces).

Chemical current sources

Calcium, as well as its alloys with aluminum and magnesium, are used in reserve thermal electric batteries as an anode (for example, a calcium-chromate element). Calcium chromate is used in such batteries as the cathode. A feature of such batteries is an extremely long shelf life (decades) in a usable condition, the ability to operate in any conditions (space, high pressures), and a high specific energy by weight and volume. The disadvantage is the short duration. Such batteries are used where it is necessary to create colossal electric power for a short time (ballistic missiles, some spacecraft, etc.).

Refractory materials

Calcium oxide, both in free form and as part of ceramic mixtures, is used in the production of refractory materials.

Medicines

Calcium compounds are widely used as an antihistamine.

• Calcium chloride

Calcium chloride (CaCl2) is a drug that replenishes Ca2+ deficiency. Solutions of calcium chloride were used as an antiallergic agent (internal).

The Ca2+ preparation compensates for the deficiency of Ca2+, which is necessary for the process of transmission of nerve impulses, contraction of skeletal and smooth muscles, myocardial activity, bone tissue formation, and blood coagulation. It reduces the permeability of cells and the vascular wall, prevents the development of inflammatory reactions, increases the body's resistance to infection and can significantly enhance phagocytosis (phagocytosis, which decreases after NaCl intake, increases after Ca2+ intake). When administered intravenously, it stimulates the sympathetic division of the autonomic nervous system, enhances the release of adrenaline by the adrenal glands, and has a moderate diuretic effect.

Approximately 1/5-1/3 of the orally administered drug is absorbed in the small intestine; this process depends on the presence of vitamin D, pH, dietary habits, and the presence of factors that can bind Ca2+. Absorption of Ca2+ increases with its deficiency and the use of a diet with a reduced content of Ca2+. In plasma, about 45% is in complex with proteins. About 20% is excreted by the kidneys, the rest (80%) is removed with the contents of the intestine.

Increased need for Ca2 + (pregnancy, lactation, period of increased body growth); bleeding of various etiology and localization (pulmonary, gastrointestinal, nasal, uterine, etc.); allergic diseases (serum sickness, urticaria, febrile syndrome, itching, angioedema); bronchial asthma, dystrophic alimentary edema, spasmophilia, tetany, pulmonary tuberculosis, rickets, osteomalacia, lead colic; hypoparathyroidism, hypocalcemia, increased vascular permeability (hemorrhagic vasculitis, radiation sickness), parenchymal hepatitis, toxic hepatitis, nephritis, eclampsia, weakness of labor, poisoning with Mg2+ salts, oxalic and fluoric acids; paroxysmal myoplegia (hyperkalemic form); inflammatory and exudative processes (pneumonia, pleurisy, adnexitis, endometritis, etc.); eczema, psoriasis.

When taken orally - gastralgia, heartburn. With intravenous administration - a feeling of heat, flushing of the skin of the face, bradycardia, with rapid administration - ventricular fibrillation of the heart. Local reactions (with intravenous administration): pain and hyperemia along the vein.

Do not inject subcutaneously or intramuscularly - tissue necrosis is possible (high concentrations of CaCl2, starting from 5%, cause severe irritation). With intravenous administration of CaCl2, a sensation of heat appears first in the oral cavity, and then throughout the body (previously used to determine the speed of blood flow - the time between the moment it was injected into a vein and the appearance of a sensation of heat).

Slows down the absorption of tetracyclines, digoxin, oral Fe preparations (the interval between their doses should be at least 2 hours). When combined with thiazide diuretics, it can increase hypercalcemia, reduce the effect of calcitonin in hypercalcemia, and reduce the bioavailability of phenytoin.

• Calcium gluconate

White powder, granular or crystalline. Soluble in water, practically insoluble in alcohol and ether. Contains up to 9% calcium.

The Ca2+ preparation compensates for the deficiency of Ca2+, which is necessary for the transmission of nerve impulses, contraction of skeletal and smooth muscles, myocardial activity, bone tissue formation, and blood coagulation.

Indications

• Diseases accompanied by hypocalcemia, increased permeability of cell membranes (including blood vessels), impaired conduction of nerve impulses in muscle tissue.

• Hypoparathyroidism (latent tetany, osteoporosis), vitamin D metabolism disorders: rickets (spasmophilia, osteomalacia), hyperphosphatemia in patients with chronic renal failure.

• Increased need for Ca2+ (pregnancy, lactation period, period of increased body growth), insufficient Ca2+ content in food, violation of its metabolism (in the postmenopausal period).

• Increased excretion of Ca2 + (prolonged bed rest, chronic diarrhea, secondary hypocalcemia against the background of long-term use of diuretics and antiepileptic drugs, corticosteroids).

• Bleeding of various etiologies; allergic diseases (serum sickness), urticaria, febrile syndrome, itching, itchy dermatoses, reactions to the administration of drugs and food intake, angioedema); bronchial asthma, dystrophic nutritional edema, pulmonary tuberculosis, lead colic; eclampsia.

• Poisoning with Mg2+ salts, oxalic and fluoric acids and their soluble salts (when interacting with calcium gluconate, insoluble and non-toxic calcium oxalate and calcium fluoride are formed).

• Parenchymal hepatitis, toxic liver damage, nephritis, hyperkalemic form of paroxysmal myoplegia.

Patients with mild hypercalciuria, a decrease in glomerular filtration rate, or a history of nephrourolithiasis should be administered under the control of urinary Ca2+ concentration. To reduce the risk of developing nephrourolithiasis, drinking plenty of water is recommended.

• calcium glycerophosphate

Calcium glycerophosphate (Latin calcium glycerophosphate) is the calcium salt of 1,2,3-propanetriol monohydrogen phosphate or dihydrogen phosphate.

Molecular formula: C3H7CaO6P

Characteristics: white crystalline powder, odorless, bitter taste. Soluble in dilute hydrochloric acid.

Pharmacological action: compensates for calcium deficiency, tonic. Restores the level of calcium in the body, stimulates anabolic processes.

Indications: hypocalcemia, decrease in overall resistance and tone in case of malnutrition, overwork, exhaustion of the nervous system, rickets.

Contraindications: hypercalcemia.

Dosage and administration: inside, adults - 0.2-0.5 g, children - 0.05-0.2 g 2-3 times a day.

In addition, calcium compounds are introduced into preparations for the prevention of osteoporosis, into vitamin complexes for pregnant women and the elderly.

The biological role of calcium

Calcium is a common macronutrient in plants, animals and humans. In humans and other vertebrates, most of it is found in the skeleton and teeth in the form of phosphates. The skeletons of most groups of invertebrates (sponges, coral polyps, mollusks, etc.) are composed of various forms of calcium carbonate (lime). Calcium ions are involved in the processes of blood coagulation, as well as in maintaining a constant osmotic pressure of the blood. Calcium ions also serve as one of the universal second messengers and regulate a variety of intracellular processes - muscle contraction, exocytosis, including the secretion of hormones and neurotransmitters, etc. The calcium concentration in the cytoplasm of human cells is about 10−7 mol, in intercellular fluids about 10− 3 mol.

The need for calcium depends on age. For adults, the required daily allowance is from 800 to 1000 milligrams (mg), and for children from 600 to 900 mg, which is very important for children due to the intensive growth of the skeleton. Most of the calcium that enters the human body with food is found in dairy products, the remaining calcium is found in meat, fish, and some plant foods (legumes are especially rich). Absorption occurs in both the large and small intestines and is facilitated by an acidic environment, vitamin D and vitamin C, lactose, and unsaturated fatty acids. The role of magnesium in calcium metabolism is also important, with its deficiency, calcium is “washed out” of the bones and deposited in the kidneys (kidney stones) and muscles.

Assimilation of calcium is prevented by aspirin, oxalic acid, estrogen derivatives. Combining with oxalic acid, calcium gives water-insoluble compounds that are components of kidney stones.

Due to the large number of processes associated with calcium, the content of calcium in the blood is precisely regulated, and with proper nutrition, deficiency does not occur. Prolonged absence from the diet can cause cramps, joint pain, drowsiness, growth defects, and constipation. A deeper deficiency leads to permanent muscle cramps and osteoporosis. Abuse of coffee and alcohol can be the causes of calcium deficiency, as part of it is excreted in the urine.

Excessive doses of calcium and vitamin D can cause hypercalcemia, followed by intense calcification of bones and tissues (mainly affecting the urinary system). A prolonged excess disrupts the functioning of muscle and nerve tissues, increases blood clotting and reduces the absorption of zinc by bone cells. The maximum daily safe dose for an adult is 1500 to 1800 milligrams.

World Health Organization Recommended Daily Values ​​for Calcium.

Children under 3 years old - 600 mg.

Children from 4 to 10 years old - 800 mg.

Children 10 to 13 years old - 1000 mg.

Adolescents 13 to 16 years old - 1200 mg.

Youth 16 and older - 1000 mg.

Adults 25 to 50 years old - 800 to 1200 mg.

Pregnant and breastfeeding women - 1500 to 2000 mg.

According to the results of American studies, calcium citrate (citrate) is most easily absorbed. So, in a study conducted with the participation of women in the postmenopausal period, it was found that the absorption of calcium citrate is 2.5 times higher than that of carbonate.

Reduced or zero acidity of the stomach is quite common. It is mainly characteristic of

older people, when the need for calcium is especially high to prevent osteoporosis. It has been established that after 50 years, low acidity is observed in approximately 40% of people. Under these conditions, the absorption of calcium carbonate, which requires hydrochloric acid to dissolve in the stomach, drops to 2%. And the absorption of calcium citrate, which does not require hydrochloric acid to dissolve in the stomach, is 44%. As a result, under conditions of reduced acidity, calcium citrate supplies 11 times more calcium to the body than carbonate.

Main sources of calcium

A lot of calcium is found in dairy products, meat, fish and seafood, nuts, turnip greens, dandelion, tofu, cabbage, legumes.

• poppy 1460
• sesame 783
• nettle 713
• plantain 412
• sardines in oil 330
• wild rose 257
• almond 25
• hazelnut 226
• soy beans dry 201
• cow's milk 120
• fish 30-90
• cottage cheese 80
• bran bread 60
• meat, offal, cereals, beets - less than 50

Assimilation of calcium is prevented by aspirin, oxalic acid, estrogen derivatives. Combining with oxalic acid, calcium gives water-insoluble compounds that are components of kidney stones.

Many natural substances are actively used by man in industry, pharmaceuticals and cosmetology. When used correctly, they can bring us enormous benefits, but even when we systematically encounter such elements in medicines, foodstuffs and cosmetics, we most often do not suspect all the variety of their qualities. Calcium carbonate can also be attributed to such substances, the use and properties of which we will now discuss in a little more detail.

Application of calcium carbonate

Calcium carbonate is mostly mined by man from various kinds of minerals, after which it is actively used in industry. So after cleaning from impurities, this substance is actively used in the creation of paper, food, plastics, paints and rubber. He found a place in the development of household chemicals, as well as in construction.

Calcium carbonate is quite actively used in the manufacture of personal care products (for example, it is added to toothpaste), as well as in the medical industry. In food production, it usually plays the role of an anti-caking agent, as well as a separator in various dairy products.

Properties of calcium carbonate

Calcium carbonate is a white powder or crystals. It has no smell or taste. Such a substance is practically insoluble in water, but quite soluble in dilute hydrochloric or nitric acid, while the dissolution process is accompanied by active release of carbon dioxide. The substance "calcium carbonate" is the source of forty percent of calcium.

medicinal properties

Calcium carbonate is able to neutralize hydrochloric acid, contributing to a significant decrease in the acidity of the digestive juice. The drug has a fairly rapid effect, however, after the cessation of the buffer effect, there is a slight increase in the production of gastric juice.

Consumption of calcium carbonate helps to reduce the activity of osteoclasts and slow down bone resorption. Such a substance well optimizes the electrolyte balance.

Among other things, calcium carbonate directly supplies the human body with calcium, which is actively involved in the processes of blood clotting, as well as in the formation of bone tissue. Calcium is also needed for the excellent functioning of the heart and for the full transmission of nerve impulses.

Application in medicine

The active substance Calcium carbonate can be used to treat patients with excessive acidity of gastric juice, as well as for diseases of the digestive system that occur against the background of such a disorder. Such ailments include exacerbation of the chronic form of gastritis, acute type of gastritis or duodenitis, symptomatic ulcerative lesions of various etiologies. Also on this list is an ulcer at the stage of exacerbation, reflux esophagitis, erosive lesions of the mucous membranes, heartburn (after excessive intake of nicotine, coffee, medications and dietary disorders).

Also, the use of calcium carbonate may be appropriate in the correction of osteoporosis, caries and rickets in children, in the treatment of tetany and osteomalacia. It is advised to take it with an increased human need for calcium, which is observed during breastfeeding, at the stage of active growth, during pregnancy and other similar conditions.

Sometimes calcium carbonate is used as adjuvant therapy for allergic reactions and hypocalcemia.

Additional Information

dosage of calcium carbonate. Application

Calcium carbonate is administered orally, without reference to the time of the meal, twice or thrice a day in the amount of 250-1000 mg.

It should be borne in mind that when consuming high doses of this drug for a long time, it is extremely important to systematically monitor the level of calcium in the patient's blood, as well as monitor the performance of the kidneys. If calcium carbonate tablets are produced in the form of tablets intended for the prevention and correction of caries, osteoporosis, and rickets, they should not be used as an antacid composition.

Contraindications for calcium carbonate

The use of calcium carbonate is categorically not recommended if the patient has hypersensitivity to this element, as well as with hypercalcemia (overdose of vitamin D, hyperparathyroidism and bone metastases). Such a medication is contraindicated in nephrourolithiasis, multiple myeloma, chronic renal failure, phenylketonuria and sarcoidosis.

Side effects of calcium carbonate

In some cases, the use of calcium carbonate can provoke allergic reactions, sometimes such treatment causes dyspeptic phenomena, represented by flatulence, epigastric pain, nausea, diarrhea or constipation. When consuming more than two grams of calcium per day, the patient is likely to develop hypercalcemia. In addition, some patients with this treatment are faced with the problem of a secondary increase in gastric secretion.

Please note that exceeding the recommended dosage may lead to an overdose of calcium carbonate. This condition requires gastric lavage and activated charcoal. In addition, symptomatic correction can be carried out, and, if necessary, measures are taken to maintain vital functions.

Thus, the active substance calcium carbonate, the properties of which we have just examined, has a fairly wide range of applications and can be of great benefit to a person.

Ekaterina, www.site

P.S. The text uses some forms characteristic of oral speech.

Calcium carbonate is a solid white crystals, odorless and tasteless, insoluble in water, ethanol and easily soluble in acids with the release of carbon dioxide. It is an inorganic chemical compound, a salt of carbonic acid and calcium. It occurs in nature in the form of minerals that differ in crystal structure - widespread calcite, aragonite and vaterite, is the main component of limestone, chalk and marble, one of the most common compounds on Earth.

Density of calcium carbonate

Density (calcite) 2.74 g/cm³, (aragonite) 2.83 g/cm³.

Melting point of calcium carbonate

Melting point (calcite) 825° C, (aragonite) 1339° C,

Decomposition temperature of calcium carbonate

Decomposition temperature 900-1000°C.

Calcium carbonate formula

Chemical formula: CaCO 3 .

Obtaining calcium carbonate

Calcium carbonate is obtained by reacting milk of lime with carbonic acid or calcium chloride (CaCl 2) with sodium carbonate (Na 2 CO 3) in an aqueous solution.

Application of calcium carbonate

Calcium carbonate (calcium carbonate, chalk, calcium salt of carbonic acid) is used:

• in the paint and varnish industry, in the production of paints and finishing materials;
• in the chemical industry in the production of calcium carbide;
• in the glass industry in the manufacture of glass;
• in construction in the production of putties, various sealants, etc.;
• in agriculture, as a lime fertilizer and for the complex agrochemical cultivation of fields;
• as a filler for rubber compounds, paper, linoleum;
• in medicine as an antacid, antiulcer, remedy for calcium deficiency;
• in the cosmetic industry in the production of tooth powder, as a filler in cosmetics;
• in the food industry, as a food additive dye E170.

Table 1. Physical and chemical parameters of calcium carbonate

Electrical properties of fillers based on calcium carbonate (2 tables):

Table 2.

Table 3

Table 4. Physical properties of different types of carbonates.

Chalk is a white sedimentary rock, soft and crumbly, insoluble in water, of organic (zoogenic) origin.

The basis of the chemical composition of chalk is calcium carbonate with a small amount of magnesium carbonate, but there is usually a non-carbonate part, mainly metal oxides. The chalk usually contains an insignificant admixture of the smallest grains of quartz and microscopic pseudomorphs of calcite after fossil marine organisms (radiolaria, etc.). Large fossils of the Cretaceous period are often found: belemnites, ammonites, etc.

Chalk - one of the most common and widely used types of fillers for composite materials is fine chalk (calcium carbonate). It is used as a filler in the production of dry building mixes; grout, plaster; paintwork materials; plastics; rubber; paper; cable products. Chalk is obtained in two ways:

Grinding rocks and sediments (natural or natural calcium carbonate);

Chemical precipitation (chemically precipitated calcium carbonate).

In rubber production, chalk is used to improve wear resistance, increase durability and elasticity in various temperature conditions, save expensive rubber and other components. Also used as an anti-adhesive for dusting rubber compounds.

white chalk: color (whiteness 78-96%), high natural dispersion, round shape of particles, easy dispersibility, relatively low hygroscopicity, low abrasiveness.

The properties that make it difficult to use chalk are its ability to aggregate with little moisture due to the high "connectivity" of the particles. This leads to its freezing and caking in bunkers, making it difficult to transport and use. To eliminate these phenomena, the chalk is subjected to surface treatment - hydrophobization, which consists in applying surface-active substances to the surface of the particles, which give the chalk the properties not to be wetted by water and cause good flowability. As water-repellent additives, stearic acid, stearin and calcium stearate or mixtures thereof are used in an amount of up to 2% by weight of the chalk. Hydrophobic chalk is a white powder with a volumetric weight of at least 700 g/dm3, its moisture content is not more than 0.2%.

Dibutyl sebacate (dbs) noos - (CH2) 8 - soon.

Description: Dibutyl sebacate is a colorless viscous liquid; soluble in toluene, acetone, hexane, ethanol. Practically insoluble in water, propylene glycol, glycerin.

Application: dibutyl sebacate is a plasticizer for polyvinyl chloride and its copolymers. polyvinyl butyral, cellulose ethers and esters, polystyrene, polyacrylates, rubbers. It is allowed to be used in polymer films for food packaging. It is also used for plasticizing varnish coatings based on polystyrene, chlorinated rubber, urea-formaldehyde resins. Gives coatings increased frost resistance. . Migration dibutyl sebacate from polyvinyl butyral gives the film increased fragility.

Specification. Appearance: Transparent liquid without mechanical impurities. Chromaticity according to the platinum-cobalt scale units. Khazen, not more than: 50 Density at 20 0 C. g / cm 3: 934-938 Acid number mg. KOH/g, not more than: 0.04 Saponification number mg. KOH/g: 354-359 Flash point deg. C, not below: 183 Specific volume cm 3 /g: 1.07 Physical properties dibutyl sebacate.

Molecular weight 314 Melting point - 12°C Boiling point 344-345°C, Vapor pressure at 60°C 0.4 Pa Solubility in water 0.005% (25°C), water in Dibutyl sebacate 1.6% (20°C) .

Plasticizers are low-volatile, high-boiling liquids, practically insoluble in water, under normal conditions resistant to hydrolysis and atmospheric oxygen. The flash and ignition temperature, the maximum permissible concentration of plasticizer vapors in the air of the working area of ​​industrial premises are given above.

Esters of o-phthalic acid in terms of effects on the body belong to the 2nd hazard class, and esters of sebacic and adipic acids - to the 3rd hazard class.