Mercury is a chemical element with the element symbol Hgperiodic table of the elementsIt is located in the 6th cycle, the IIB family, the 80th place, commonly known as mercury, and other nicknames such as "white water, beautiful women, water glue, yuan water, lead essence, flowing beads, yuan beads, red mercury, sand mercury, spirit liquid, Huobao, Ziming". It is the only metal that exists in liquid state under normal temperature and pressure.
Mercury is a silvery white shiny heavy liquid that can evaporate at room temperature.Metallic mercury hasReducibility，Oxidized stateThere are two forms of expression:+2 and+1.Mercury is an inert metal, andoxygenThe combination is slow, but withsulfurIn the case of mixed grinding, it will react to produce non-toxicMercuric sulfide(HgS), which can be used to treat spilled mercury.Mercury insoluble in reducibilityacidAnd insoluble inalkali, but soluble inOxidizing acid, such asnitric acidThermalconcentrated sulfuric acid。Mercury is an element with strong neurotoxicity. Its single substance and various compounds have different degrees of toxicity, which can cause chronic poisoning.
Mercury has a long history of use and is widely used.In the Middle AgesalchemyMiddle andsulfur, salt alchemyHoly Three Elements。
From August 16, 2017《Minamata Convention on Mercury》Effective for China, it is specified that "from January 1, 2026, the production of mercury containing thermometers and mercury containing sphygmomanometers will be prohibited[1]。”On October 27, the list of carcinogens released by the International Agency for Research on Cancer of the World Health Organization (WHO) was preliminarily collated for reference. Mercury and inorganic mercury compounds were included in the list of three types of carcinogens.[10]On July 23, 2019, mercury and mercury compounds were included in the list of toxic and harmful water pollutants (the first batch)[2]。
Mercury has a very small distribution in nature and is considered to beRare metalsBut people discovered mercury very early.The natural mercury sulfide, also known as cinnabar, has been used as a red pigment for a long time because of its bright red color.Unearthed from Yin RuinsOracleCoated withCinnabarIt can be proved that China has used natural mercury sulfide before history.
According to ancient Chinese documentsFirst Emperor of QinBefore death, some princes also used infusion mercury in their tombs, such asDuke Huan of QiBuried in Linzi (now Zibo City, Shandong ProvinceLinzi District）The pool is made of mercury poured from its tomb.This means that China had already obtained a large amount of mercury in the 7th century BC or earlier.
In ancient China, mercury was also used as a surgical drug.1973Han Tomb at Mawangdui in ChangshaThe fifty-two prescriptions in the unearthed silk manuscripts were copied in the Qin and Han Dynasties. They are the most ancient medical prescriptions in China that have been excavated and may be in the Warring States Period.Mercury is used in four prescriptions.For example, use mercury and realgar to treat scabies.
In ancient China, working people used red sand (i.eMercuric sulfide）And calcine in air to obtain mercury.However, the generated mercury is easy to volatilize and difficult to collect, and the operator willMercury poisoning。The working people of China have accumulated experience in practice, and they have changed to airtight mercury production, some in bamboo tubes, and some in closed pomegranate jars.
According to the data of western chemical history, a small tube of mercury was found in an ancient Egyptian tomb, which is the product of the 16th - 15th century BC according to historical research.But the working people in ancient China first made a lot of mercury.[4]
Western alchemists also became interested in mercury.Western alchemists believe that mercury is the commonality of all metals - the embodiment of metallicity.What they think of as metallicity is an "element" that makes up all metals.
From August 16, 2017《Minamata Convention on Mercury》It came into force for China, which clearly stated that "from January 1, 2026, the production of mercury containing thermometers and mercury containing sphygmomanometers will be prohibited."[1]
On October 27, 2017, the list of carcinogens published by the International Agency for Research on Cancer of the World Health Organization (WHO) was preliminarily collated for reference. Mercury and inorganic mercury compounds were included in the list of three types of carcinogens.
On July 23, 2019, mercury and mercury compounds were included in the list of toxic and harmful water pollutants (the first batch).[2]
the distribution of mineral deposits
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Mineral reserves
Mercury is a naturally occurring element found in air, water and soil.
Mercury is a highly toxic and nonessential element, which widely exists in various environmental media andfood chain(especially fish), its tracks are all over the world.
The world's mercury resources are about 700000 tons, and the basic reserves are 300000 tons.The major countries with mercury reserves and their basic reserves include Spain 90000 tons, Italy 69000 tons, China 81400 tons and Kyrgyzstan 45000 tons.Mercury deposits in the world are mainly distributed in the Tethys Himalayan tectonic belt.Mercury depositThe main type is carbonate type, followed by clastic rock type and magmatic rock type.Carbonate type is the most important, accounting for 90% of the reserves of mercury deposits.
Mercury deposits are located in the Lower Cambrian strata, and their occurrence and enrichment are strictly controlled by the structure, rock association and wall rock alteration.The main ore body is bedded and stratoid, and there are also bedded lenticular ore bodies with obvious stratabound characteristics. It is a stratabound deposit and is recognized as the most typical "bedded mercury deposit" in China, which is of great significance to the exploration and research of mercury at home and abroad.The ore is single, mainly cinnabar.The output is mainly star shaped and disseminated, followed by vein shaped and banded.The ore dressing and smelting performance is good.
Migration and transformation
（1） Mercury cycle is a typical cycle of heavy metals in the ecosystem. Mercury migrates and transforms in water, soil, atmosphere and biosphere as an element.
（2） Main characteristics of mercury migration and transformation:
(1) Mercury is the only heavy metal that can complete the cycle in the ecosystem.After mercury is discharged into the water, it passes through the food chain, and the fish in the mercury polluted waterMethylmercuryThe concentration can be ten thousand times higher than that in water.
(2) The mercury cycle shows complex processes including: migration of particulate matter;Settlement of dry and wet materials;Volcanic volatilization into the atmosphere;Enter water to deposit sludge;Methylmercury is produced under the action of bacteria;Entering organism;Accumulation in organisms.
(3) Biological methylation: under the action of microorganisms, inorganic mercury such as metallic mercury and divalent ionic mercury will be converted into methylmercury and dimethylmercury, which is called the biological methylation of mercury.
(4) Methylmercury is easy to be absorbed by human body, discharged slowly, and toxic.This is because methylmercury is easily soluble in lipids;Mercury is not easy to decompose in the body because of the carbon mercury bond in its molecular structure;It is a high nerve poison, mostly accumulated in the brain.
physical property
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physical property
melting point
-38.9 °C
boiling point
356.6 °C (lit.)
density
13.59 g/cmthree
character
Shiny silver white heavy liquid
It is the only metal that exists in liquid state at normal temperature and pressure.It has strong cohesion and is stable in the air. It evaporates mercury vapor at normal temperature, which is highly toxic.Natural mercury is a mixture of seven isotopes of mercury.Mercury is slightly soluble in water, and its solubility increases in the presence of air.Mercury is ubiquitous in nature. Generally, animals and plants contain trace amounts of mercury, so we have trace amounts of mercury in our food, which can be metabolized through excretion, hair, etc.
Alloy:Mercury is easy to form alloys with most common metals, which are collectively called amalgam (or amalgam).Metals that can form alloys with mercury include gold and silver, but do not includeironTherefore, iron powder has always been used to replace mercury.Other transition metals in the first row are difficult to form alloys, but they do not include manganese, copper and zinc.Other elements that are not easy to form alloy with mercury areplatinumAnd some other metals.Sodium amalgamIt is commonly used in organic synthesisreducing agent, also used forHigh pressure sodium lampMedium.When mercury contacts the pure metal of aluminum, they are easy to form aluminum amalgam, because aluminum amalgam can destroy the oxide layer of aluminum that prevents continuous oxidation（Brush experiment）Therefore, even a small amount of mercury can seriously corrode aluminum.For this reason, in most cases, mercury cannot be carried on the aircraft because it is easy to form an alloy with the exposed aluminum parts on the aircraft and cause danger.[5]
Liquid:As a metal, mercury exists strangely as a liquid at room temperature.The theory of relativistic shrinkage effect can provide an explanation for this unusual phenomenon.Similar to gold, the 6s orbit of mercury shrinks and tends to stabilize at the same time, leading to a so-called "inert electron pair" effect: the 6s orbit of mercurytwoThe shell is inert during bonding.6s of mercury can be seentwo6p excitation energy is far more than the corresponding excitation energy of cadmium and zinc.According to the general periodic law, the energy interval should followPrincipal quantum numberIncrease and decrease.Therefore, it is expected that the energy interval from zinc to cadmium will become smaller, while the energy interval from cadmium to mercury will suddenly increase.Here we can see again that it is the relativistic contraction effect that causes the full 6stwoThe shell is safe and stable, so 6s of mercurytwo6p energy interval increases sharply.As long as the required excitation energy is not available, it is inert for 6stwoThere is no strong bond between the mercury atoms in the shell.ground stateHgtwoOnly byVan der WaalsThey maintain each other, so the metal mercury is liquid at room temperature.[5]
chemical property
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1. It can volatilize rapidly under high temperature.React with azide, acetylene or ammonia to form explosive compounds.Contact with ethylene, chlorine, triazomethane and sodium carbide will cause severe reaction.The staff should take good care of protection. If they accidentally touch the eyes, they should immediately wash them with a large amount of flowing water.
2. Generally, it does not react with hydrogen or rare gases, but can be directly combined with all halogens and sulfur vapors.It is not oxidized by air at normal temperature. When heated to boiling, it can slowly react with oxygen to generate mercury oxide.React with ammonia in air to produce millon base (HgtwoNOH·2HtwoO)。
3. It does not oxidize at room temperature, but can volatilize. It is oxidized to mercury oxide when heated.It can be fused with other metals except iron to form an alloy (amalgam), which is toxic, and vapor inhalation has cumulative hazards.Sodium amalgam is a common reducing agent in organic synthesis, and also used in high-pressure sodium lamp.When mercury contacts the pure metal of aluminum, it is easy to form aluminum amalgam. Because aluminum amalgam can destroy the oxide layer (brush test) that prevents the continuous oxidation of aluminum metal, even a small amount of mercury can seriously corrode aluminum metal.For this reason, in most cases, mercury cannot be carried on the aircraft because it is easy to form an alloy with the exposed aluminum parts on the aircraft and cause danger.[5]
4. Dissolve in nitric acid and hot concentrated sulfuric acid to generate mercuric nitrate and mercuric sulfate respectively, and mercurous salt will appear in excess of mercury.It can dissolve many metals to form an alloy, which is called amalgam.The valence is+1 and+2.Like silver, mercury can react with hydrogen sulfide in air.Mercury has a constant volume expansion coefficient, its metal activity is lower than zinc and cadmium, and hydrogen cannot be replaced from acid solution.Generally, the valence of mercury compounds is+1 or+2. The mercury compounds with the valence of+4 only have mercury tetrafluoride, while the mercury compounds with the valence of+3 do not exist.[11]
Introduction to toxicology
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It should be noted that,TraceIngestion of liquid mercury will not cause serious toxic reaction[6](It is reported that it can form organic compounds in the organism), but mercury vapor and mercury salt (except for some extremely low solubility such as mercury sulfide) are highly toxic, which can cause brain and liver damage after oral administration, inhalation or contact.General use of thermometeralcoholInstead of mercury, the thermometers used in the People's Republic of China (excluding Hong Kong, Macao and Taiwan) are still using mercury.China plans to phase out the use of mercury thermometers by 2015.
The most dangerous mercury organic compounds areDimethylmercury[(CHthree)twoHg]，Only a few microliters (10-9mthreeOr 10-6dmthreeOr 10-3cmthree）DimethylmercuryContact with skin can cause death.
Mercury can be accumulated in organisms and easily absorbed by skin, respiratory tract and digestive tract.Minamata diseaseIt is a kind of mercury poisoning.Mercury destructioncentral nervous systemIt has adverse effects on mouth, mucosa and teeth.Long term exposure to high mercury environment can lead to brain damage and death.Although the boiling point of mercury is very high, the saturated mercury vapor at indoor temperature has reached several times of the toxic dose.[7]
Preparation method
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1. The cinnabar is heated in flowing air, reduced to obtain mercury vapor, and the vapor is condensed and collected to obtain mercury metal.
2. After crushing and flotation enrichment, cinnabar ore is roasted in air or heated with quicklime to distill mercury.This method is commonly used in industry.[12]
application area
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The most common applications of mercury are industrial chemicals and applications in electronic or electrical products.Mercury is also used in thermometers, especially when measuring high temperatures.More and more gaseous mercury is still used to manufacture fluorescent lamps, while many other applications are gradually eliminated due to problems affecting health and safety, and Galinstan alloy, which is less toxic but much more expensive, is replaced.In addition, the uses of mercury include:
1. It can decompose gold from its minerals, so it is often used in gold mines.
2. Used for making barometer, diffusion pump and other instruments.
3. Gaseous mercury is used for mercury vapor lamps.
4. Used to make liquid mirror telescopes.A telescope that uses rotation to make the liquid form a paraboloid shape and uses it as the main mirror for astronomical observation. Its price is one-third of that of an ordinary telescope.
5. Mercury switches, pesticides, preservatives in the production of chlorine and potassium hydroxide, electrodes, batteries and catalysts in some electrolytic equipment.
Medical field
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Mercury from《This Sutra》。《The Classic of Materia Medica》: Mercury, which is said in the Sutra to come from red sand, is that coarse cinnabar is picked from the rocks and used as a furnace to place sand in the middle. The lower part is connected with water, and the upper part is covered with an implement. With the addition of fire, the smoke will fly up, and the mercury will slip down, and its color will be small and white.As for those from the Western Qiang, they are also burning like this.However, there are a lot of plants growing in the mountain. As for the self splitting of a mountain, people can pick up large pieces of sand and stones like buckets, which can be burned. Therefore, the amount of mercury coming from the west is much more than that from the south.《Materia Medica Derivation》: Mercury is coagulated when lead is obtained, and it is coagulated when sulfur is obtained. It is dispersed when jujube meat is grinded.Do not calcine it into greasy powder and cream.Sipping and killing lice.《Compendium》: Mercury, if lost on the ground, is collected with Sichuan pepper powder or tea powder.《Fengyuan in this sutra》: Mercury is insidious and cannot enter people's stomach.Today, I ate mercury by mistake. I weighed heavily in my stomach. I cut it into two jin of pig fat and baked it in small pieces. I could eat it with raw honey.
pharmacological action
1. Mercury (mercury) compounds have disinfection, purgative, diuretic effects, and are now not used or rarely used.The elemental mercury does not cause pharmacological effects. The dissociated mercury ion can combine with the alkyl group and interfere with the metabolism and function of cells.The elemental mercury cannot be absorbed from the gastrointestinal tract, but its surface can form oxides or sulfides when exposed to the air, so it can sometimes cause mild diarrhea and diuresis after ingestion.Most people who swallow mercury have no symptoms. Mercury is excreted from feces. A few people may have some symptoms, and very few (sensitive or other unknown causes) may cause immediate death.
2. Mercury is a protoplasm toxin, which can interact with the pathogenBiological respirationThe sulfhydryl group in the enzyme binds to inhibit its viability, and finally suffocates it to death.
3. Mercury excretion is mainly from the kidney, followed by the large intestine.
Pharmacology
Mercury can corrode the digestive tract, damage the kidneys and capillaries.Acute poisoning is mostly caused by accidental ingestion of mercuric chloride, with symptoms caused by digestive tract corrosion. After absorption, kidney damage will occur, resulting in urination and capillary damage, resulting in plasma loss, and even shock.Early application of dimercaptopropanol and other symptomatic measures are most effective.Chronic poisoning is generally seen in industrial poisoning, where stomatitis and toxic encephalopathy occur, and the latter shows depression, shrinking and other mental symptoms and muscle tremor.
Common selection
1. The treatment of scabies is not bad for years: one or two of mercury, one or two of alum, one or two of cnidia, one or two of realgar, one or two of rumpus.When applying medicine, half a kilogram of pig fat was refined, and all of them studied the mercury stars. Then they applied it and served it three or two times a day.（《Shenghuifang》Mercury cream)
2. Treatment of dry ringworm: mercury, beard powder.Study the tune and paint it.（《Behind elbow》）
3. Cure heat sores, scabies, itching and unbearable pain: mercury, wucatkin.Crisp and apply.(Near Effective Recipe)
4. Cure myrica canker: mercury, black lead, yellow lead, frankincense, myrrh, each five cents.At the end of the day, the paper roll was used as a small wrench, the oil was dyed and the lamp was lit, and the sunburn (fumigation) occurred three times.(Compendium)
5. In the treatment of hemorrhoids, there are more than two insects itching in the valley path: two taels of mercury and two taels of jujube paste.With the same research phase, Nian, such as jujube shape, wrapped in thin cotton, the lower part.In case of pain, add powder to make pills.(Mei Shiji's Prescriptions)
7. Treatment of underarm odor: mercury, beard powder.Add two flavors, grind and apply with flour fat.
Drug contraindication
1. It is not suitable for taking orally, especially for pregnant women.
2. External use should not be excessive or prolonged to avoid poisoning.
3、《Extracts of Materia Medica》: People who suffer from scabies are usually smeared with mercury, which is slippery and heavy, and should be careful when it goes straight into the meat.
4、《Herbal Classic》: Head sores must not be used. If you are afraid of getting into the muscles and collaterals, you must slow down the muscles and bones. It should be applied externally rather than taken internally.
test method
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Determination of total mercury
Atomic fluorescence spectrometry
Principle: After the sample is heated and digested by acid, the mercury in the sample is dissolved by potassium borohydride (KBHfour）Or sodium borohydride (NaBHfour）It is reduced to atomic mercury, which is brought into the atomizer by carrier gas (argon). Under the irradiation of a special mercury hollow cathode lamp, the ground state mercury atom is excited to a high energy state. When it is deactivated and returned to the ground state, it emits fluorescence of a characteristic wavelength. Its fluorescence intensity is proportional to the mercury content, and is quantified by comparison with the standard series.
Cold atomic absorption spectrometry
Principle: mercury vapor has a strong absorption effect on the resonance line with a wavelength of 253.7 nm.After acid digestion or catalytic acid digestion of the sample, mercury is converted to ionic state. In strong acidic medium, stannous chloride is reduced to elemental mercury. With nitrogen or dry air as the carrier, elemental mercury is blown into the mercury analyzer for cold atomic absorption measurement. In a certain concentration range, its absorption value is proportional to the mercury content, and compared with the standard series for quantification.
Dithizone colorimetry
Principle: After the sample is digested, mercury ion can form orange red complex with dithizone in acid solution, which is soluble inTrichloromethane, quantitative comparison with standard series.
Methylmercury determination
Gas chromatography
Principle: Methylmercury in the sample is grinded with sodium chloride and then added with hydrochloric acid (1+11) containing copper ions. After complete extraction, the supernatant is adjusted to a certain acidity through centrifugation or filtration, adsorbed with sulfhydryl cotton, eluted with hydrochloric acid (1+5), and finally extracted with benzene and analyzed by gas chromatography with an electronic capture identifier.
Cold atomic absorption method
Principle: the same as gas chromatography.But in alkaline medium, it is measured by mercury detector, and compared with the standard series for quantification.[8]
Disposal of leakage
The widely used thermometer, sphygmomanometer and other equipment have caused environmental problems such as mercury pollution in the room. Do not panic if you break the mercury thermometer in the room. You can immediately hold the mercury beads visible to the naked eye with a piece of paper (because of the great cohesion of mercury, you can't pick up mercury with a cotton swab, which is extremely unscientific and irresponsible) and put them into a sealed water bottle,If there are small mercury beads that can be pushed together with a piece of paper, the mercury will be automatically gathered into small balls and then collected.For safety, nitric acid can be used to wipe the mercury contaminated ground when there are some simple chemicals to completely eliminate mercury pollution.The reaction of mercury with sulfur can be carried out without heating.Therefore, the scattered mercury can be covered with sulfur powder to make sulfur and mercury combine to form HgS, so as to prevent mercury vapor from entering the air and causing poisoning.[9]In order to completely remove mercury pollution, iodine vapor fumigation can also be used to fumigate the room several times until the cuprous iodide test paper does not change color.[7]Experiments have proved that the mercury leaked daily can be stuck and collected with household transparent tape, which is better than paper. This method can be used to deal with mercury leakage of thermometer and sphygmomanometer.
Storage method
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1. Store in a cool and ventilated warehouse.
2. Keep away from kindling and heat sources.The warehouse temperature should not exceed 30 ℃.It shall be stored separately from combustibles and acids, and mixed storage is strictly prohibited.The storage area shall be equipped with leakage emergency treatment equipment and appropriate materials.[11]
