Stages of industrial production of mercury. Mercury: interesting facts

General information and methods of obtaining

Mercury (Hg) is a silvery-white heavy metal that is liquid at room temperature. When frozen, mercury turns white, in the solid state it is easily processed and has a granular fracture. Native mercury was known for 2000 BC. e. The peoples of ancient India and China, as well as the Greeks and Romans used cinnabar (natural HgS) as a paint, medicine and cosmetic. The Greek physician Dioscorides (1st century BC), heating cinnabar in an iron vessel with a lid, obtained mercury in the form of vapors that condensed on its inner surface. The reaction product was named hydrargyros

(from the Greek hydor - "water" and argyros - "silver"), i.e. liquid silver. The origin of the Russian name "mercury" is not established

Solid mercury was first obtained in 1759 in St. Petersburg by M. P. Braun and M. V. Lomonosov, who managed to freeze it in a mixture of snow with concentrated nitric acid.

Mercury is a very rare element. Its average content in the earth's crust is 4.5-10% (by mass). Approximately the same amount is found in igneous rocks. There are 35 known ore minerals containing mercury in concentrations at which the industrial use of these minerals is technically possible and economically feasible. The main ore mineral is cinnabar HgS

Mercury ores are divided into rich (~ 1% Hg), ordinary (0.2-0.3% Hg) and poor (0.06-0.12% Hg). Telethermal deposits of mercury ores, which are mined underground, are of the main industrial importance. Mercury is also found in developed open way volcanogenic deposits.

There are two main methods for extracting mercury - pyro- and hydrometallurgical. In the first case, ores or concentrates containing mercury in the form of HgS are subjected to oxidative roasting. The liquid mercury obtained as a result of roasting flows into special receivers. For subsequent purification, it is passed through a tall (1.0-1.5 m) vessel with 10% HN 0 3 , washed with water, dried and distilled in a vacuum. The second way to obtain mercury is to dissolve HgS in sodium sulfide and then replace mercury with aluminum. Methods for extracting mercury by electrolysis of sulfide solutions have been developed.

Physical Properties

Atomic characteristics. Atomic number 80, atomic mass 200.59 a. e. m., atomic volume 14.26 * 10 -6 m 3 / mol, atomic radius 0.157 nm, non-radius Hg 2+ 0.110 nm. Configuration of outer electron shells 5d 10 6s 2 . Ionization potentials J (eV): 10.43; 18.76; 34.21. Electronegativity 1.44. Solid mercury has a rhombohedral lattice with periods a=0.3463 and c=0.671 nm. There are seven known stable isotopes of mercury. mass numbers: 196 (prevalence 0.2%), 198 (10%), 199 (16.8%), 200 (23.1%), 201 (13.2%), 202 (29.8%) and 204 ( 6.9%).

Chemical properties

In compounds, it exhibits an oxidation state of +2 and +1.

Mercury is a relatively stable chemical element. In relation to oxygen, it ranks close to gold and silver. Of the metals of the znnk subgroup, mercury is the least active due to the high ionization energy. Normal electrode potentials of dissociation reactions 2 Hg -> - (Hg 2) 2+ + 2 e, (Hg 2) 2+ ^-2 Hg 2 ++2 e n Hg -> -- "- Hg 2+ + 2 e are equal respectively 0.80; 0.91 n ​​0.86 V. The electrochemical equivalent of mercury with an oxidation state of +1 is 2.0789 mg/C, and with an oxidation state of +2, 1.03947 mg/C. Mercury compounds are relatively unstable due to the constant tendency of mercury to change into atomic form.

In hydrochloric and dilute sulfuric acids, as well as in alkalis, mercury does not dissolve. Easily soluble in nitric acid, and when heated in concentrated sulfuric. Soluble in aqua regia. With weak acids, mercury does not give salts or forms unstable salts of the Hg 2 CQ 3 type, which, when heated to 180 ° C, decomposes into mercury, its oxide n CO 2.

With halogens, mercury forms almost non-dissociating, mostly toxic compounds. Iodine mercury Hgl 2, mercury chloride (calomel) Hg 2 Cl 2 and mercury chloride (mercuric chloride) HgCl 2 are of practical importance. Mercury iodine is produced by the action of potassium iodine on mercury dissolved in water. In analytical chemistry, this reaction detects the presence of mercury. Iodine mercury exists in two modifications - red and yellow. The transition from red to yellow modification occurs at 127 °C; the reverse transition proceeds slowly and requires supercooling. Calomel is colorless tetrahedral crystals, gradually darkening due to decomposition under the action of light into sublimate and mercury. Sublimate has a vnd of colorless rhombic crystals. Most often, sublimate is obtained by direct reduction of mercury.

Mercury dissolves in molten white phosphorus, but does not form chemical compounds and, upon cooling, is released from the melt in a chemically unchanged form.

Mercury sulphide can be obtained by simply rubbing mercury with sulfur at room temperature. Mercury sulfide HgS can be easily obtained by exposing mercury to hydrogen sulfide elevated temperatures.

In air, mercury at room temperature does not oxidize. With prolonged heating to temperatures close to the boiling point, mercury combines with atmospheric oxygen, forming red mercury oxide (I) HgO, which, upon further heating, again decomposes into mercury and oxygen. In this compound, the oxidation state of mercury is + 2. Another mercury oxide is also known - black. The oxidation state of mercury in it is +1, its formula is Hg 2 0 In all mercury (I) compounds, its atoms are interconnected, forming divalent groups - Hg 2 - iln - Hg - Hg -. A similar relationship is also preserved in solutions of mercury (I) salts.

The existence of HgH 2 hydride, obtained as a result of the interaction of mercury nodide and lithium - aluminum hydride, is known. However, mercury hydride is very unstable and decomposes already at 148 K.

Mercury hydroxides are unknown. In those cases where they can be expected to form, they, due to their instability, immediately split off water, forming anhydrous oxides.

In addition to the halides, other mercury salts are also known. Among them, mercury sulfide HgS; salts of mercury (I) cyanic and thiocyanic acids are known, as well as "mercury fulminate" - a salt of fulminating acid - Hg (ONC) 2. Almost all suns of mercury (I) are poorly soluble in water. The exception is Hg nitrate (N 0 3) 2 . When mercury is exposed to ammonia, numerous complex compounds are formed, for example, white fusible precipitate HgCl -2 NH 3, white infusible precipitate HgNH 2 Cl, etc. Two main types of organomercury compounds are known: R - Hg - R "n R - HgX, where R and R "are organic radicals, X is an acid residue. Ethn compounds can be obtained by the interaction of mercury salts with magnesium or organolithium compounds by replacing hydrogen in organic compounds with mercury (mercuration), by adding mercury salts to unsaturated compounds, and, finally, by decomposing dnasonium salts in the presence of mercury salts (Nesmeyanov's reaction) .

When metals are dissolved in mercury, amalgams are formed (only metals wetted by mercury are susceptible to amalgamation). They do not differ from conventional alloys, although in excess of mercury they are semi-liquid mixtures. In this case, amalgams can be either ordinary (true) solutions (Sn, Pb) and mixtures (Zn, Cd), or chemical compounds (group I elements). According to the interaction with mercury, metals can be divided into five groups:

Metals whose solubility has not been precisely established (Ta, Si, Re, W, Sb);

Metals practically insoluble in mercury [solubility not higher than 2-10-5% (by mass): Cr, Co, Fe, V, Be];

Metals with very low solubility (at the level of the metals mentioned above), but forming chemical compounds with it (Ni, Ti, Mo, Mn, U);

Metals that do not react with mercury at normal temperatures

but interacting with it at elevated temperatures or after preliminary grinding (Al, Cu, Hf, Ge);

Metals that form solid solutions with mercury, and some of them also chemical compounds.

The compounds resulting from amalgamation readily decompose below their melting point, releasing excess mercury.

State diagrams of Au - Hg , Ag - Hg , Pt - Hg and Sn - Hg have characteristic transition points corresponding to the decomposition of chemical compounds formed during amalgamation under various temperature conditions. With these compounds, mercury forms a series metal connections Steels alloyed with carbon, silicon, chromium, nickel, molybdenum and niobium are not amalgamated.

Areas of use

Mercury is widely used in the manufacture of various instruments (barometers, thermometers, manometers, vacuum pumps, normal elements, polarographs, electrometers, etc.); in mercury lamps, switches, rectifiers; as a liquid cathode in the production of caustic alkalis and chlorine by electrolysis; as a catalyst in the synthesis of acetic acid; in metallurgy for gold and silver amalgamation; in the manufacture explosives(explosive mercury); in medicine (calomel, sublimate, mercury-organic and other compounds); as a pigment (cinnabar); in agriculture as a seed disinfectant and herbicide (organic mercury compounds); in shipbuilding for painting (paint component) of marine vessels, as well as in medical practice.

It is hardly necessary to prove that mercury is a peculiar metal. This is obvious, if only because mercury- the only metal that is in a liquid state under conditions that we call normal. Why liquid mercury is a special question. But it is precisely this property, or rather the combination of the properties of a metal and a liquid (the heaviest liquid!), that determined the special position of element No. 80 in our life. Much can be said about mercury: dozens of books are devoted to liquid metal. The same story is mainly about the variety of uses of mercury and its compounds.
Mercury's involvement in the glorious clan of metals long time was in doubt. Even Lomonosov hesitated whether mercury could be considered a metal, despite the fact that in the liquid state it has almost full range metallic properties: thermal and electrical conductivity, metallic luster and so on. When mercury is cooled to - 39°C, it becomes quite obvious that it is one of the "light bodies that can be forged."

Properties of mercury

Mercury has rendered great services to science. How can one know how much the progress of technology and the natural sciences would have been delayed without measuring instruments- thermometers, manometers, barometers and others, the action of which is based on the unusual properties of mercury. What are these properties?

• First, mercury is a liquid.
• Secondly, a heavy liquid is 13.6 times heavier than water.
• Thirdly, it has a rather large coefficient of thermal expansion - only one and a half times less than that of water, and an order of magnitude, or even two, more than that of ordinary metals.

There are also “fourths”, “fifths”, “twenties”, but it is hardly necessary to list everything.
Another curious detail: "millimeter of mercury" is not the only physical unit associated with element number 80. One of the definitions of the ohm, the unit of electrical resistance, is the resistance of a column of mercury 106.3 cm long and 1 mm 2 in cross section.
All this is not only about pure science. Thermometers, pressure gauges and other devices "stuffed" with mercury have long become the property of not only laboratories, but also factories. And mercury lamps, mercury rectifiers! The same unique combination of properties has given mercury access to a variety of branches of technology, including radio electronics and automation.
Mercury rectifiers, for example, have long been the most important and powerful type of electrical rectifier most widely used in industry. Until now, they are used in many electrochemical industries and in vehicles with electric traction, although in last years they are gradually being replaced by more economical and harmless semiconductor rectifiers.
Modern Combat vehicles also uses the remarkable properties of liquid metal.
For example, one of the main parts of a fuse for an anti-aircraft projectile is a porous ring made of iron or nickel. The pores are filled with mercury. Shot - the projectile has moved, it acquires everything great speed, rotates faster and faster around its axis, and heavy mercury protrudes from the pores. It closes the electrical circuit - an explosion.
Often you can meet her where you least expect. Sometimes it is alloyed with other metals. Small additions of element No. 80 increase the hardness of the lead-alkaline earth metal alloy. Even when soldering, sometimes mercury is needed: solder made from 93% lead, 3% tin and 4% mercury is the best material for soldering galvanized pipes.

Mercury amalgams

Another remarkable property of mercury is the ability to dissolve other metals, forming solid or liquid solutions - amalgams. Some, such as silver and cadmium amalgams, are chemically inert and hard at temperatures human body but soften easily when heated. They make dental fillings.
Thallium amalgam, which hardens only at -60°C, is used in special designs of low-temperature thermometers.
Antique mirrors were covered not with a thin layer of silver, as is done now, but with an amalgam, which included 70% tin and 30% mercury. In the past, amalgamation was the most important technological process when extracting gold from ores. In the 20th century, it could not stand the competition and gave way to a more advanced process - cyanidation. However, the old process is still used today, mainly in the extraction of gold, which is finely embedded in ore.
Some metals, in particular iron, cobalt, nickel, are practically not amenable to amalgamation. This makes it possible to transport liquid metal in plain steel tanks. (Pure mercury is transported in glass, ceramic or plastic containers.) In addition to iron and its analogues, tantalum, silicon, rhenium, tungsten, vanadium, beryllium, titanium, manganese and molybdenum are not amalgamated, that is, almost all metals used for alloying become. This means that mercury is not afraid of alloyed steel.
But sodium, for example, amalgamates very easily. Sodium amalgam is easily decomposed by water. These two circumstances have played and continue to play a very important role in the chlorine industry.
in the production of chlorine and caustic soda by electrolysis table salt cathodes made of metallic mercury are used. To obtain a ton of caustic soda, one needs from 125 to 400 g of element No. 80. Today, the chlorine industry is one of the largest consumers of metallic mercury.

• THE FIRST SUPERCONDUCTOR. Almost a century and a half after the experiments of Priestley and Lavoisier, Hg turned out to be involved in another outstanding discovery, this time in the field of physics. In 1911, the Dutch scientist Geike Kamerling-Onnes investigated the electrical conductivity of mercury at low temperatures. With each experiment, he reduced the temperature, and when it reached 4.12 K, the resistance of mercury, which had been successively decreasing before, suddenly disappeared completely: electricity passed through the mercury ring without fading. Thus, the phenomenon of superconductivity was discovered, and element No. 80 became the first superconductor. Now dozens of alloys and pure metals are known that acquire this property at a temperature close to absolute zero.

• HOW TO CLEAR Hg. In chemical laboratories, it is often necessary to purify liquid metal. The method described in this note is perhaps the simplest of the reliable ones and the most reliable of the simple ones. A glass tube with a diameter of 1-2 cm is attached to a tripod; the lower end of the tube is pulled back and bent. Diluted water is poured into the tube nitric acid with about 5% mercuric nitrate Hg 2 (N0 3) 2 . From above, a funnel with a paper filter is inserted into the tube, in the bottom of which a small hole is made with a needle. The funnel is filled with contaminated mercury. On the filter, it is cleaned of mechanical impurities, and in the tube - from most of the metals dissolved in it. How does this happen? Mercury is a noble metal, and impurities, such as copper, displace it from Hg 2 (N0 3) 2; some impurities are simply dissolved by acid. Purified mercury is collected at the bottom of the tube and, under the influence of its own gravity, is transferred to a receiving vessel. By repeating this operation several times, it is possible to quite completely clear it of impurities of all metals standing in the series of voltages to the left of mercury.

Clear mercury from noble metals, such as gold and silver, is much more difficult. To separate them, vacuum distillation is used.

• SOMETHING LIKE WATER. Not only the liquid state makes it related to water. The heat capacity of mercury, like water, with increasing temperature (from the melting point to +80°C) consistently decreases and only after a certain temperature "threshold" (after 80°C) begins to slowly increase. If element #80 is cooled very slowly, like water, it can be supercooled. In a supercooled state, liquid mercury exists at temperatures below -50° Ct; usually, it freezes at -38.9°C. By the way, for the first time it was frozen in 1759 by the St. Petersburg academician I.A. Brown.
• NO ONE-VALENT MERCURY! This statement will seem untrue to many. Indeed, even at school they teach that, like copper, mercury can show valencies +2 and 1+. Compounds such as black oxide Hg 2 0 or calomel Hg 2 Cl 2 are widely known. But Hg here is only formally univalent. Studies have shown that all such compounds contain a group of two mercury atoms: -Hg 2 - or -Hg-Hg-. Both atoms are divalent, but one valence of each of them is spent on the formation of a chain, similar to the carbon chains of many organic compounds. The Hg 2 +2 ion is unstable, unstable and the compounds in which it enters, especially mercuric hydroxide and carbonate. The latter quickly decompose into Hg and HgO and, accordingly, H 2 0 or CO 2 .

POISON AND ANTIDOTE.
I would prefer the worst death to work in the mercury mines, where the teeth crumble in the mouth ...
R. Kipling
Vapors of mercury and its compounds are indeed very toxic. Liquid mercury is dangerous primarily due to its volatility: if it is stored open in a laboratory room, then a partial pressure of mercury of 0.001 will be created in the air. This is a lot, especially since the maximum permissible concentration of mercury in industrial premises is 0.01 mg per cubic meter of air.
The degree of the toxic effect of metallic mercury is determined primarily by how much it managed to react in the body before it was removed from there, that is, it is not mercury itself that is dangerous, but its compounds.
Acute poisoning with mercury salts is manifested in intestinal upset, vomiting, swelling of the gums. A decline in cardiac activity is characteristic, the pulse becomes rare and weak, fainting is possible. The first thing to do in such a situation is to find out the patient is vomiting. Then give him milk and egg whites. It is excreted from the body mainly by the kidneys. In chronic poisoning with Hg and its compounds, a metallic taste in the mouth, friability of the gums, severe salivation, slight excitability, and memory loss appear. There is a danger of such poisoning in all rooms where Hg is in contact with air. Particularly dangerous are the smallest drops of spilled mercury, crammed under baseboards, linoleum, furniture, in the cracks of the floor. The total surface of small mercury balls is large, and evaporation is more intense. Therefore, accidentally spilled Hg must be carefully collected. All places where the smallest droplets of liquid metal could linger must be treated with a solution of FeCl 3 in order to chemically bind mercury.

• Spacecraft of our time require significant amounts of electricity. Engine regulation, communication, Scientific research, the operation of the life support system - all this requires electricity ... So far, the main sources of current are batteries and solar panels. The energy requirements of spacecraft are growing and will continue to grow. Spaceships of the near future will need power plants on board. At the heart of one of the variants of such stations is a nuclear turbine generator. In many ways, it is similar to a conventional thermal power plant, but the working fluid in it is not water vapor, but mercury. Heats up its radioisotope fuel. The cycle of operation of such an installation is closed: mercury vapor, having passed through the turbine, condenses and returns to the boiler, where it heats up again and is again sent to rotate the turbine.
• ISOTOPS. The natural element consists of a mixture of seven stable isotopes with mass numbers 196, 198, 199, 200, 201, 202 and 204. The heaviest isotope is the most common: its share is almost 30%, more precisely, 29.8. The second most common isotope is mercury-200 (23.13%). And the least of all in the natural mixture of mercury-190 - only 0.146%.

Of the radioactive isotopes of element No. 80, and there are 23 of them known, practical value purchased only mercury-203 (half-life 46.9 days) and mercury-205 (5.5 minutes). They are used in the analytical determination of mercury and the study of its behavior in technological processes.

• THE BIGGEST DEPOSITS ARE IN EUROPE. This is one of the few metals, the largest deposits of which are located on the European mainland. The largest deposits of mercury are Almaden (Spain), Monte Amyata (Italy) and Idriya (Yugoslavia).
• NAME REACTIONS. For the chemical industry, it is still quite important not only as a material for cathodes in the production of chlorine and caustic soda, but also as a catalyst. For example, from acetylene according to the reaction of M.G. Kucherov, discovered in 1881, acetaldehyde is obtained. The catalyst here is a mercury-containing salt, such as sulfate HgSO 4 . But when dissolving spent uranium blocks, mercury itself was used as a catalyst. The Kucherov reaction is not the only "named" reaction involving mercury or its compounds. The reaction of A.N. Nesmeyanov, during which, in the presence of mercury salts, organic diazonium salts are decomposed and organomercury compounds are formed. They are used mainly for the production of other organoelement compounds and, to a limited extent, as fungicides.

Influence on emotions. It affects the body as a whole and, of course, the psyche. It has been suggested that mercury intoxication can cause outbursts of unbridled anger. Ivan the Terrible, for example, often used mercury ointments for joint pain and, perhaps, his increased excitability is the result of mercury poisoning? Doctors thoroughly studied the symptoms of mercury poisoning, including psychophysical ones: a feeling of an impending catastrophe, delirium, hallucinations ... Pathologists who examined the ashes of the formidable king noted an increased content of mercury in the bones.

They indicate that mercury leaked out during a fire in the building of the Research Institute of Vacuum Technology. In the fire seat, the concentration of mercury vapor exceeded the MPC, but outside the territory (as well as in the territory itself after work on the neutralization of mercury) there was no deviation from the limits of the standards.

For an objective picture and unambiguous exclusion (or confirmation) of large-scale mercury contamination, it is necessary to carry out not one measurement, but several dozen, and in different time. Without such data, one can only point out that with a really large release, the concentration of mercury would vary greatly in different areas of the city. And if someone 15 or 20 kilometers from the fire site complains of symptoms of mercury poisoning, then nearby the number of poisoned people should clearly number in the thousands: the population density in the capital in some places exceeds 50 thousand inhabitants per square kilometer.

In other words, rumors of a serious and threatening everyone residents of the leak seem extremely doubtful. The Moscow air is dirty, but it is unlikely because of mercury. Moreover, problems with smog began long before the fire: the smell of burning came to the city in the summer, and then the smoke was attributed to peat bogs burning in the Tver region. But since we are talking about mercury, we decided to make a selection of ten statements about the toxicity of this element.

1) Mercury - extremely dangerous substance. If you accidentally drink a drop of mercury, you can die immediately.

Metallic mercury, contrary to popular belief, is neither a potent poison nor a particularly toxic substance. Suffice it to say that a case is described in the medical literature when a patient swallowed 220 grams of liquid metal and survived. For comparison: the same amount of table salt can lead to lethal outcome(unless, of course, someone is able to eat a glass of salt). Detailed guide In chapter " deaths» deals with mercury chloride poisoning, but does not contain a single mention of fatal mercury poisoning in the form of pure metal. In addition, mercury has been and continues to be used to make dental fillings based on amalgam, an alloy of mercury with other metals. Such fillings are recognized as safe enough and it is not recommended to replace amalgam with other materials without special need.

Pure mercury in liquid form, even if swallowed, is not particularly dangerous. But this cannot be said about metal vapors, much less about mercury compounds.

2) Mercury is dangerous because it evaporates and produces toxic fumes.

It really is. Mercury vapor is formed where the metal is exposed to the open air. They have no smell, no color, and - as a rule - taste, although sometimes people feel a metallic taste in their mouths. Constant inhalation of polluted air causes mercury to enter the body through the lungs, which is much more dangerous than swallowing the same amount of metal.

3) If the thermometer crashed in the apartment, you must carefully sweep and wash the floor.

Not only incorrect, but also frankly wrecking statement. When one drop is divided into two, the specific area and, accordingly, the rate of evaporation of the substance double. Therefore, do not try to brush mercury with a broom or a rag into a scoop, and then throw it into the trash can or flush it down the toilet. In this case, part of the metal will inevitably fly out in the form of tiny balls, which quickly evaporate and pollute the air much more actively than the original drop. And we hope that none of the readers will collect mercury with a vacuum cleaner: it not only crushes the drops, but also heats them up. If you already have one spilled drop, then simply drive it with a wet brush into a hermetically sealed jar and then hand it over to the DEZ (Single Customer Directorate; first, it’s better to call and find out if they accept it. The recommendation is given for Russia, in other countries the rules may differ) . You can use a piece of paper or, if the drop is small, a small syringe.

American researchers who experimented with mercury in 2008 found that one drop of 4 millimeters in diameter even in a small room of 20 cubic meters after an hour gives only 0.29 micrograms of mercury vapor per cubic meter. This value is within the limits of both the US and Russian standards for atmospheric pollution. However, when mercury was smeared with a mop, the concentration of its vapors rose to over one hundred micrograms per cubic meter. That is, ten times higher than the MPC for industrial premises and hundreds of times higher than the “general atmospheric” norm! Wet cleaning, as experiments have shown, does not save mercury after sweeping, and the floor remains contaminated with thousands of small drops after repeated wiping with a wet cloth.

4) If a thermometer is broken in the apartment, then the room is long years becomes life threatening.

This is true, but not always. The evaporation of metallic mercury after some time slows down due to the coating of the metal with a film of mercury oxide, so drops that have rolled into the cracks can lie for years and even decades. Handbook of forensic science Environmental Forensics: Contaminant Specific Guide with reference to several studies, it is said that mercury somewhere under the floor or behind the baseboard ceases to pollute the atmosphere over time, but only on the condition that its balls are not mechanically affected there. If a mercury ball falls into a gap between parquet boards, where it is constantly shaken when walking, evaporation will continue until the drop has evaporated completely. A three-millimeter ball, estimated by physicists in 2003, evaporates in three years.

5) Mercury poisoning manifests itself immediately.

True only for high concentrations of mercury.

Acute poisoning occurs when air is inhaled for several hours, in which more than one hundred micrograms per cubic meter. At the same time, serious (requiring hospitalization) consequences occur at even higher concentrations. To seriously poison yourself with mercury, one broken thermometer is not enough.

For chronic mercury poisoning, based on those presented in the already mentioned Toxicological profile for mercury data, concentration needed heavy metal at least over ten micrograms per cubic meter. This is possible if broken thermometer swept away with a broom and did not neutralize the mercury, however, even in this case, the inhabitants of the room are unlikely to feel unwell immediately. Mercury in relatively low concentrations does not lead to instant nausea, weakness and fever, but can, for example, cause incoordination and trembling of the limbs. Rashes can also occur in young children, but there is no specific set of symptoms by which even a layman could identify chronic mercury poisoning.

6) Mercury is present in fish and seafood.

Truth. Pure mercury is converted to methylmercury by some bacteria and then moves up the food chain, primarily in marine biosystems. The last phrase means that at first the plankton containing methylmercury is eaten by fish, then these fish are eaten by predators (other fish) and each time the concentration of methylmercury in organisms increases due to its ability to accumulate in animal tissues. Studies conducted by oceanologists have shown that the amount of mercury in the transition from water and substances dissolved in it to plankton increases by tens or even hundreds of thousands of times.

The concentration of mercury in tuna meat reaches 0.2 milligrams per kilogram. Mercury contamination of fish has become a serious problem, the solution of which requires the coordinated work of environmentalists and industry representatives around the world. However, for the majority of Russians, who, in principle, rarely eat fish (18 kilograms per year versus 24 kg in the United States), this source of mercury is not so significant.

7) If you break a fluorescent lamp, it will pollute the room with mercury.

Truth. In 2004, a group of American scientists saw a row of lamps inside a plastic barrel, which was immediately covered with a lid. Experience has shown that fragments slowly release mercury vapor and up to forty percent of the toxic metal contained inside can come out of the remains of a light bulb.

Most compact lamps contain about 5 milligrams of mercury inside (there are brands with amounts reduced to one milligram). If we take into account that on the first day about half of those forty percent that, in principle, can leave fragments, is released, then one lamp broken in a room will exceed the “atmospheric” MPC by five to ten times, but will not go beyond the “working-industrial” MPC . Fragments that have lain for a week are already practically harmless from the point of view of air contamination with mercury vapor, so because of one broken light bulb You can't get mercury poisoning.

Another thing is to break several dozen large fluorescent lamps at once. Such actions, as practice shows, lead to acute mercury poisoning.

8) Most city dwellers are chronically poisoned by mercury.

A highly dubious claim. The concentration of mercury in the air of cities is indeed higher, but so far there is no convincing evidence that this leads to any diseases. Mercury eventually ends up in the atmosphere and water near many volcanoes. There are deposits that have been developed since antiquity, whole ones have been built near them and their inhabitants do not suffer from poisoning.

Reveal Negative influence both mercury and other substances (or not substances, but, say, microwave radiation from mobile phones) at low doses is quite difficult. What manifests itself only after many years requires long-term observations. But over the course of twenty or thirty years, people usually develop a variety of illnesses, many of which may have nothing to do with the suspected substance. If you observe a few tens of thousands of people, then some of them will develop chronic diseases and even malignant tumors anyway, without any connection with mercury, radiation or another factor. Even the well-known harm of smoking today was not immediately revealed: only closer to the middle of the last century, doctors were able to unequivocally link smoking with lung cancer.

Representatives of “alternative medicine” often talk about chronic mercury poisoning, but they cannot be considered objective sources. Many of them simultaneously sell some sort of “detox program,” often with the promise of curing diseases supposedly caused by mercury, such as cancer or autism. The official position of American doctors now is that the drugs used to remove mercury from the body (the so-called chelate compounds) will harm healthy people rather than help. At least three cases of fatal poisoning have been described as a result of attempts to "cleanse the body of mercury."

9) Mercury is found in vaccines.

Mercury is part of thiomersal, a preservative used in some vaccine preparations. One dose of the vaccine usually contains about 50 micrograms of the substance. For comparison: the lethal dose of the same substance (established in experiments on mice) is 45 milligrams (45,000 micrograms) per kilogram of body weight. One serving of fish can contain about the same amount of mercury as a dose of vaccine.

Thiomersal was blamed for the increase in the number of cases of autism, but back in the early 2000s, this hypothesis was refuted by an analysis of statistical information. Also, assuming mercury is the issue, the increase in autism cases over the past few decades remains unclear. Formerly people contacted with mercury much more actively.

10) Mercury pollution is a problem of the last decades.

This is not true. Mercury is one of the oldest metals known to mankind, as is cinnabar, mercury sulfide. Cinnabar was actively used as a red dye (including for the production of cosmetics!), while mercury was used in a number of processes, from applying gilding to making hats. When gilding domes St. Isaac's Cathedral fatal poisonings sixty craftsmen received mercury, and the expression "mad hatter" reflects the symptoms of chronic poisoning when dressing skins for men's hats. Until the middle of the 20th century, toxic mercury nitride was used in the processing of skins. Mercury was also included in the composition of many drugs, and in dosages incomparable with thiomersal. Calomel, for example, is mercury(I) chloride and has been used as an antiseptic along with sublimate, mercury(II) chloride.

In recent decades, the use of mercury in medicine has declined sharply due to the toxicity of this metal. You can meet the same calomel only in homeopathic preparations. Or in "folk" medicine - a number of mercury poisonings have been recorded after the use of Chinese traditional medicine preparations.

Help: Why is mercury poisonous?

Mercury interacts with selenium. Selenium is a trace element that is part of thioredoxin reductase, an enzyme that reduces the protein thioredoxin. Thioredoxin is involved in many vital processes. In particular, thioredoxin is needed to fight cell-damaging free radicals, in which case it works in conjunction with vitamins C and E. Mercury irreversibly damages thioredoxin reductase, and it stops reducing thioredoxin. There is not enough thioredoxin, and as a result, the cells cope worse with free radicals.

DEFINITION

Mercury- the eightieth element of the Periodic table. Designation - Hg from the Latin "hydrargyrum". Located in the sixth period, IIB group. Refers to metals. The core charge is 80.

Mercury is not widely distributed in nature; its content in the earth's crust is only about 10 -6% (wt.). Occasionally, mercury is found in its native form, interspersed in rocks; but it is chiefly found in nature as the bright red mercuric sulfide HgS, or cinnabar. This mineral is used to make red paint.

Mercury is the only metal that is liquid at room temperature. As a simple substance mercury is a silvery white (Fig. 1) metal. Very fusible metal. Density 13.55 g/cm 3 . Melting point - 38.9 o C, boiling point 357 o C.

Rice. 1. Mercury. Appearance.

Atomic and molecular weight of mercury

DEFINITION

Relative molecular weight of a substance (M r) is a number showing how many times the mass of a given molecule is greater than 1/12 of the mass of a carbon atom, and relative atomic mass of an element (A r)- how many times average weight atoms chemical element more than 1/12 of the mass of a carbon atom.

Since in the free state mercury exists in the form of monatomic Hg molecules, the values ​​of its atomic and molecular weight match. They are equal to 200.592.

Isotopes of mercury

It is known that in nature mercury can be found in the form of seven stable isotopes 196 Hg (0.155%), 198 Hg (10.04%), 199 Hg (16.94%), 200 Hg (23.14%), 201 Hg ( 13.17%), 202 Hg (29.74%) and 204 Hg (6.82%). Their mass numbers are 196, 198, 199, 200, 201, 202 and 204, respectively. The nucleus of the atom of the mercury isotope 196 Hg contains eighty protons and one hundred and sixteen neutrons, and the rest differ from it only in the number of neutrons.

There are artificial unstable radioactive isotopes of mercury with mass numbers from 171 to 210, as well as more than ten isomer states of nuclei.

mercury ions

At the outer energy level of the mercury atom, there are two electrons that are valence:

1s 2 2s 2 2p 6 3s 2 3p 6 3d 10 4s 2 4p 6 4d 10 4f 14 5s 2 5p 6 5d 10 6s 2 .

As a result of chemical interaction, mercury gives up its valence electrons, i.e. is their donor, and turns into a positively charged ion:

Hg 0 -1e → Hg + ;

Hg 0 -2e → Hg 2+.

Mercury molecule and atom

In the free state, mercury exists in the form of monatomic Hg molecules. Here are some properties that characterize the atom and molecule of mercury.

Mercury (English Mercury, French Mercure, German Quecksilber) is one of the seven metals of antiquity. She was known at least for 1500 years BC, even then they knew how to get her from cinnabar. Mercury was used in Egypt, India, Mesopotamia and China; it was considered the most important starting substance in the operations of the sacred secret art for the manufacture of drugs that prolong life and are called pills of immortality. In IV - III centuries. BC. mercury as liquid silver (from Greek water and silver) is mentioned by Aristotle and Theophrastus. Dioscorides later described the production of mercury from cinnabar by heating the latter with coal. Mercury was considered the basis of metals, close to gold, and therefore was called Mercury (Mercurius), after the planet Mercury closest to the sun (gold). On the other hand, believing that mercury is a certain state of silver, the ancient people called it liquid silver (from where the Latin Hydrargirum came from). The mobility of mercury gave rise to another name - living silver (lat. Argentum vivum); The German word Quecksilber comes from the Low Saxon Quick (live) and Silber (silver). It is interesting that the Bulgarian designation for mercury - zhivak - and the Azerbaijani - jiva - are probably borrowed from the Slavs.

In Hellenistic Egypt and the Greeks, the name Scythian water was used, which makes it possible to think about the export of mercury from Scythia at some point in time. In the Arab period of the development of chemistry, the mercury-sulfur theory of the composition of metals arose, according to which mercury was revered as the mother of metals, and sulfur (sulphur) as their father. Many secret Arabic names of mercury have been preserved, which testifies to its importance in alchemical covert operations. The efforts of Arab, and later Western European alchemists, were reduced to the so-called fixation of mercury, i.e., to its transformation into a solid substance. According to the alchemists, the resulting pure silver (philosophical) easily turned into gold. The legendary Vasily Valentin (XVI century) founded the theory of the three principles of alchemists (Tria principia) - mercury, sulfur and salt; this theory was further developed by Paracelsus. In the vast majority of alchemical treatises, outlining the methods of transmutation of metals, mercury is in the first place either as the initial metal for any operations, or as the basis of the philosopher's stone (philosophical mercury). Of the secret alchemical (part of Arabic origin) or mystical names for mercury, we give the names nitrogen (Azoth, or Azoq), Zaibac, Zeida, Zaibar (Saibar), Ventus albus, Argentum vivum, and others. Alchemists distinguished many types of mercury and accompanied it with the common name Mercurius various epithets (mercury of metals, minerals, mercury syroy, weak, etc.). The origin of the Russian and Slavic names for the metal (Czech rtut", rdut", Slovenian ortut", Polish rtec, trtec) is unclear. In ancient Russian literature, this word is found already in the 16th century. Philologists believe that it is associated with the Turkic utarid, meaning the planet Mercury. This assumption is supported by the alchemical name Tarith - according to Ruland: "the same as Ruscias" (Russian?). A. M. Vasiliev believes that the connection with the Turkic root indicates the influence on our ancestors with the planets. At one time, the author of these lines pointed out the possibility of a purely Slavic word formation of the name mercury from ore, rudra or ore, denoting red, blood, red paint and red in general. This comparison is based on the red color of cinnabar - the compound from which mercury was obtained It is known that since ancient times cinnabar has been mined in some areas of modern Donbass.This issue requires additional research.