Book: How the chemical elements were discovered. Finding palladium in nature

oh, but with a mixture of six elements - platinum metals, which by that time had not been discovered. For example, when osmium was absent in platinum, the metal was not volatile and did not catch fire; in the presence of osmium, the alloy was volatile and burned.

What year is considered the date of discovery of platinum? Metal has come a long way before it got the right to exist. Perhaps the most important date in the history of the discovery of platinum is 1750 ch, because it was then that it was studied and described in sufficient detail.

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Even at the end of the XVI century. Brazilian miners have repeatedly discovered a strange alloy in nature. He appeared under various names. It was supposed to contain gold and silver. Perhaps it was an alloy of palladium and gold. But the real discovery of the second of the platinum metals took place in 1803, thanks to the work of the English chemist W. Wollaston. While studying raw (unrefined) platinum, he dissolved it in aqua regia, removed the excess acid, and added mercury cyanide to the solution. A yellow precipitate fell out. By heating it with sulfur and borax, W. Wollaston obtained shiny metal balls. He named the new metal palladium (in honor of the Pallas asteroid discovered a year earlier by astronomer V. Olbers). The success of W. Wollaston is largely due to the fact that he correctly found the palladium precipitant - mercury cyanide, which does not precipitate other platinum metals.

The discovery of palladium received publicity in a rather curious way. The young Irish chemist R. Chenewiaks in 1804 advertised in the "Journal of Chemical Education" about a "new metal for sale", which represented co. an alloy of platinum with mercury. W. Wollaston, of course, did not agree with this opinion and defended his discovery with the article "On a new metal found in raw platinum." In it, he emphasized that the metal offered for sale (an allusion to the words of Chenevix. - Aug.), called palladium, is contained in platinum ores, although in small proportions.

Contemporaries (including L. Vauquelin) highly appreciated the achievement of W. Wollaston, especially since this scientist soon discovered another platinum metal - rhodium. The primacy of palladium isolation can probably be explained by the fact that it is the most common platinum metal. In addition, it is found in nature in its native state. This was shown (on the example of Brazilian platinum ores, which were the only source of research before the discovery of Ural platinum) in 1809 by W. Wollaston, and in 1825 by A. Humboldt.

Palladium served as the key to the discovery of relatives, which occurred at the turn of 1803 - 1804, that is, even before the news of palladin penetrated into wide circles.

The source of relatives was also raw platinum, of course, from the deposits of South America. It is not known only whether this was the same sample in which W. Wollaston discovered palladium. After dissolving a portion of raw platinum in aqua regia and neutralizing the excess acid with alkali, the discoverer Palladin first added an ammonium salt to precipitate the platinum as ammonium chloroplatinate. Mercury cyanide was added to the remaining solution (this is where skills in isolating palladium came in handy), palladium cyanide turned out to be in the sediment. After cleaning the solution from excess mercury cyanide and evaporating the solution to dryness, W. Wollaston observed a beautiful dark red precipitate, which, in his opinion, was double sodium chloride and a new metal.

This salt readily decomposed when heated in a stream of hydrogen, leaving behind a metal powder after removal of the sodium chloride. The scientist also prepared a new metal in the form of balls. Rhodium got its name in connection with the red color of its first received salt (in Greek, genus means "rose").

This element is perhaps the least common of all the platinum metals. For him, only one own mineral is known - will give birth, found in the gold-bearing sands of Brazil and Colombia. At the same time, several minerals are known for other platinum metals.

OSMIA AND IRIDIUM

Until now, there has never been a case in the history of science when four new elements, with similar properties, were discovered at once in one country, in England, within two years. Simultaneously with Wollaston, his compatriot S. Tennant was engaged in the study of platinum metals. But if the discovery of palladin and relatives belongs to W. Wollaston, then the isolation of osmium and iridium is associated with the names of other scientists, although the merit of S. Tennant is the greatest.

Palladium (lat. Palladium) in the periodic system is denoted by the symbol Pd - a chemical element with atomic number 46 and atomic mass 106.42. It is an element of the second triad (platinum metals) of the secondary subgroup, the eighth group of the fifth transitional period of the periodic system of Dmitry Ivanovich Mendeleev. Palladium is a silver-white noble metal similar in appearance to silver, but their similarities do not end there, because the forty-sixth element is the lightest of the platinum metals. In terms of density (12.02 g/cm3), palladium is closer to silver (10.49 g/cm3) than to its related platinum (21.5 g/cm3). Palladium is a heavy, refractory, malleable metal that is easily rolled into foil and drawn into thin wire.

Natural palladium consists of six stable isotopes: 102Pd (1.00%), 104Pd (11.14%), 105Pd (22.33%), 106Pd (27.33%), 108Pd (26.46%) and 110Pd ( 11.72%). The longest-lived artificial radioactive isotope is 107Pd, with a half-life of seven million years. Many isotopes of palladium are produced in comparatively small amounts in the fission of uranium and plutonium nuclei. In modern nuclear reactors, 1 ton of nuclear fuel with a burnup of 3% contains about 1.5 kg of palladium.

Palladium was discovered by the English physician and chemist William Wollaston in 1803 while studying raw platinum brought from South America, in that part of it that is soluble in aqua regia. Having dissolved the ore, Wollaston neutralized the acid with a solution of NaOH, after which he precipitated platinum from the solution by the action of ammonium chloride NH4Cl (ammonium chloroplatinate precipitates). Mercury cyanide was then added to the solution to form palladium cyanide. Pure palladium was isolated from cyanide by heating. Only a year later, Wollaston reported to the Royal Society that he had discovered palladium and another new noble metal, rhodium, in raw platinum. The very name of the new element - palladium (Palladium) Wollaston derived from the name of the minor planet Pallas (Pallas), discovered shortly before (1801) by the German astronomer Olbers.

The forty-sixth element, due to a number of its remarkable physical and chemical properties, has found wide application in many areas of science and life. So some types of laboratory glassware are made from palladium, as well as parts of equipment for the separation of hydrogen isotopes. Alloys of palladium with other metals find a very valuable application. For example, alloys of the forty-sixth element with silver are used in communication equipment (contact manufacturing). Temperature controllers and thermocouples use alloys of palladium with gold, platinum and rhodium. Certain alloys of palladium are used in jewelry, dentistry (dentures) and even used to make parts for pacemakers.

When applied to porcelain, asbestos and other supports, palladium serves as a catalyst for a number of redox reactions, which is widely used in the synthesis of a number of organic compounds. The palladium catalyst is used to purify hydrogen from traces of oxygen, as well as oxygen from traces of hydrogen. A solution of palladium chloride is an excellent indicator of the presence of carbon monoxide in the air. Palladium coatings are applied to electrical contacts to prevent sparking and increase their corrosion resistance (palladium).

In jewelry, palladium is used both as a component of alloys and on its own. In addition, the Bank of Russia mints palladium commemorative coins in very limited quantities. A small amount of palladium is consumed for medical purposes - the preparation of cytostatic drugs - in the form of complex compounds, similar to cis-platinum.

Biological properties

Scientists definitely cannot say anything about the biological role of palladium in living organisms, perhaps further studies of the properties of this platinoid will reveal its significance in certain biological processes.

Nevertheless, the role of this element in medicine is quite large. So in some countries (including Russia) a certain amount of palladium is used to obtain cytostatic drugs - in the form of complex compounds, similar to cis-platinum. Immediately after the discovery of the cytostatic effect of platinum by Rosenberg, scientists around the world began to study this phenomenon and synthesize more and more effective and safe platinum compounds for medical purposes. In recent years, the world's leading medical institutions and large companies have been trying to find bioactive drugs among other compounds of the platinum group, including palladium. This noble metal kills and slows down the growth of cancer cells no worse than platinum, but it is almost ten times less toxic. Anticancer drugs based on palladium are undergoing the latest clinical trials and may soon be in service with oncologists.

Another rather important purpose of palladium and its alloys is associated with the high biological compatibility of this metal - the manufacture of medical instruments, parts of pacemakers and dentures. Even now, the use of traditional base alloys based on cobalt, nickel and chromium for orthopedic dentistry is significantly reduced due to the frequent occurrence of adverse reactions in a number of patients sensitive to the influence of base metals.

What will replace obsolete materials? The answer is obvious - noble metal alloys, including platinoids and palladium in particular. One of these alloys is palladant ("Superpal"), containing 60% palladium and 10% gold. The alloy has a beautiful silver-gray metallic color, reliable strength characteristics, and is biologically compatible. In maxillofacial surgery, it is used for the manufacture of extended bridges. Another alloy containing palladium is plagodent ("Super KM"). 98% consists of precious metals (except for palladium it contains gold and platinum), has a light yellow color and is intended for the manufacture of cast prostheses, inlays, semi-crowns, bridges, mainly with a ceramic or glass-ceramic coating.

Palladium is also used in the food industry. After it became clear in a number of countries that nickel was the cause of a surge in allergies in the population, many blamed dishes made from this material. However, subsequent studies disproved this hypothesis and established the true cause of the allergic reaction - nickel was found in food, and more specifically in margarine made from vegetable oil. The fact is that according to the technological process, the oil must become solid, for this it is hydrogenated, that is, the molecules are saturated with hydrogen using a catalyst. Nickel played the role of such for a long time. To intensify the process, the catalyst powder is intensively mixed with vegetable oil at high temperature, and then the catalyst is removed by filtration, however, nickel is not completely removed, and if the process fails, then a rather large amount of this allergen enters the final product.

It was possible to solve this problem thanks to the developments of scientists from the Petrochemical Institute named after A.V. Topchiev. They managed to create a catalyst based on palladium deposited on aluminum oxide. This introduction made it possible to solve several problems at once: palladium is inert and safe for humans, in addition, it is many times more effective than nickel, which means that it needs a thousand times less. There are other advantages of the palladium catalyst - it is easier to remove it from the final product and the structure of the molecules of the latter is "deciphered" by the body more easily than in the case of a nickel catalyst, so "palladium" margarine is easier to digest.

It is known that palladium is often used by jewelers in alloys with other precious metals. So alloys of the 583rd and 750th tests, called "white gold", can contain ten percent or more palladium. In our country, the government officially established palladium 500 and 850 samples. These samples are most common in jewelry.

Another popular palladium hallmark is 950. This is due to the fact that wedding rings are made of such a grade metal, as an alternative to white gold rings with rhodium plating. The fact is that rhodium is quickly erased from the surface of the ring, and not everyone will be able to renew the expensive coating every year. Palladium rings have exactly the same appearance as gold rings, but do not require annual renewal. In addition to standard palladium alloys, decorative palladium-indium compounds are sometimes used in jewelry production, forming a wide range of colors from golden to lilac. However, products made from such an alloy are very rare.

In 1988, for the first time, 25-ruble coins were minted from palladium in the series “1000th Anniversary of Old Russian Coinage, Literature, Architecture, Baptism of Rus'”. On a coin weighing 31.1 g of the highest 999 test, a monument to Prince Vladimir Svyatoslavovich in Kyiv is depicted. In Basel, at the International Numismatic Exhibition, this series was recognized as the best program of the year, receiving the first prize for the quality of execution.

The release of such coins was limited and did not last long, for this reason the coins have a high collectible value. The most valuable are two series of coins (1993-1994 issue): “The first Russian round-the-world trip. 1803-1806 "-" Sloop "Hope"" with a portrait of I.F. Kruzenshtern, "Sloop" Neva "(Yu.F. Lisyansky)". The second series “The First Russian Antarctic Expedition. 1819-1821 "-" Sloop "Mirny" (M.P. Lazarev)", "Sloop" Vostok "(F. F. Bellingshausen)". Also presented are coins of the series "Russia and World Culture" - "A. Rublev, M. P. Mussorgsky”, coins of the “Russian Ballet” series and dedicated to Russian monarchs.

There are many awards and prizes in the world that are awarded to outstanding scientists. There is a William Hyde Wollaston medal made of pure palladium. This award was established almost two centuries ago (1831) by the London Geological Society and was initially made of gold. Only in 1846, the famous English metallurgist Johnson extracted pure palladium from Brazilian palladium gold, which was intended exclusively for the manufacture of this medal. Among those awarded the Wollaston medal was Charles Darwin, and in 1943 the medal was awarded to the Soviet scientist Academician Alexander Evgenievich Fersman for his outstanding mineralogical and geochemical research. Now this medal is kept in the State Historical Museum.

However, this is not the only palladium medal. The second, awarded for outstanding work in the field of electrochemistry and the theory of corrosion processes, was established by the American Electrochemical Society. In 1957, this award was awarded to the works of the largest Soviet electrochemist, Academician A.I. Frumkin.

The merits of William Wollaston include not only the discovery of palladium (1803) and rhodium (1804), the production of the first pure platinum (1803), but also the discovery of ultraviolet radiation independent of J. Ritter. In addition, Wollaston designed a refractometer (1802) and a goniometer (1809).

The palladium industry in Russia appeared relatively late. It was not until 1922 that the State Refinery produced the first batch of Russian refined palladium. This marked the beginning of the industrial production of palladium in our country.

It is known that palladium is able to enhance the anti-corrosion properties of even such a metal resistant to aggressive environments, like titanium. The addition of palladium in just 1% increases the resistance of titanium to sulfuric and hydrochloric acids. So for a year in hydrochloric acid, a plate made of a new alloy loses only 0.1 millimeters of its thickness, while pure titanium thins by 19 millimeters over the same period. A solution of calcium chloride does not affect the alloy at all, while titanium annually loses up to two millimeters in an aggressive environment. What is the secret of such an alloy? The fact is that the acid interacts primarily with palladium and immediately the surface of the second component of the alloy is covered with the thinnest oxide film - the part, as it were, puts on a protective shirt. This phenomenon was called by scientists the self-passivation (self-protection) of metals.

Story

The honor of discovering palladium belongs to the Englishman William Hyde Wollaston, who isolated the new metal from the raw platinum of South American mines in 1803. Who is the man who is named after the pure palladium medal awarded annually by the Geological Society of London?

At the end of the eighteenth century, William Wollaston was one of the many obscure London doctors who practiced in poor working-class areas. A job that did not bring income could not suit an intelligent and enterprising young man. In those days, the doctor had to have the skills not only of a physician, but also to master the pharmaceutical business, which in turn required an excellent knowledge of chemistry. W.H. Wollaston turned out to be an excellent chemist - while studying platinum, he invented a new method for making platinum dishes and set up its production. It is worth mentioning that in those years, platinum glassware for chemical laboratories was a necessity, because the excitement around scientific discoveries was the same as in the days of alchemists around the philosopher's stone. It is no coincidence that at the turn of the XVIII and XIX centuries. discovered about 20 new chemical elements!

It is not surprising that the Englishman's new enterprise began to bring him a considerable income, sufficient to leave the unpromising medical practice. Products manufactured by Wollaston were in demand far beyond the foggy Albion, allowing the Englishman to engage in new chemical research without worrying about the money issue. Improving the technique of refining and cleaning platinum from impurities, the chemist came to the idea of the possibility of the existence of platinum-like metals.

The platinum that Wollaston had to work with was a by-product obtained from the washing of gold sands in the distant Colombian Republic. In addition to gold, it contained mercury impurities, which had to be removed. He dissolved raw platinum in aqua regia, after which he precipitated only platinum from the solution - with especially pure ammonia NH4Cl. It was then that Wollaston noted that the precipitated solution had a pink hue, which impurities such as gold and mercury could not give. By adding zinc to the colored solution, the chemist obtained a black precipitate, which he dried and then dissolved in aqua regia. It turned out that only part of the black powder was dissolved. Diluting the concentrate with water, Wollaston added potassium cyanide, as a result of which a copious orange precipitate formed, which turned gray when heated. The gray precipitate was fused into metal, which was less than mercury in specific gravity. Having dissolved the resulting metal in nitric acid, Wollaston obtained a soluble part, which was palladium and an insoluble part, from which he isolated another platinoid, rhodium.

Rhodium got its name from the Greek word for “pink”, because rhodium salts give the solution a pink color. As for palladium, Wollaston named it after an earlier astronomical discovery. Shortly before the discovery of palladium and rhodium (in 1802), the German astronomer Olbers discovered a small planet in the solar system and named it Pallas in honor of the ancient Greek goddess of wisdom, Athena Pallas.

What did Wollaston do after the discovery of a new element? He did not immediately announce this, but circulated an anonymous advertisement for the sale of the new palladium metal in the store of the mineral dealer Forster. The message about a new noble metal - "new silver" interested many, including the chemist Richard Cheneviks. Having a typical hot-tempered and uncontrollable Irish character, Chenevix wanted to expose the "fraudulent trick" and, neglecting the high price, bought a palladium bar and began to analyze it.

Soon, the Irishman suggested that the metal was not a new element at all, but was made from platinum by alloying it with mercury according to the method of the Russian scientist A. A. Musin-Pushkin. This opinion Cheneviks hastened to express - first in a report read before members of the Royal Society of London, and then in the general press. In response, the anonymous advertiser announced that he was willing to pay £20 to anyone who could artificially prepare the new metal using Chenevix's proposed method. However, other chemists, and even Chenevix himself, with all their efforts, could not find either mercury or platinum in palladium ...

Only some time later, Wollaston officially announced that he was the author of the discovery of palladium and described a method for obtaining it from raw platinum. At the same time, he reported on the discovery and properties of another platinum metal - rhodium. In addition, he said that he was the anonymous seller of the new metal, who set a premium for its artificial preparation.

Such an interesting and extraordinary person was William Hyde Wollaston - a little-known London doctor and a world famous chemist - the discoverer of palladium and rhodium.

Being in nature

Palladium is one of the rarest metals, its average concentration in the earth's crust is 1∙10-6% by mass, however, this is twice as much as gold contained in the earth's crust (5∙10-7%). William Wollaston had to extract palladium from grains of Columbian native platinum, the only mineral known at that time to contain palladium. Nowadays, geochemists can name about 30 minerals that include this noble metal.

Like platinum, the forty-sixth element occurs in its native form (unlike the rest of the platinoids), while it may contain impurities of other metals: platinum, gold, silver and iridium. In appearance, it is rather difficult to distinguish it from native platinum, but it is much lighter and softer than it. Quite often, palladium itself is an impurity in native gold or platinum. So, palladium platinum containing 40% palladium was found in the ores of Norilsk, and in Brazil (Minas Gerais state) a very rare and little-studied variety of native gold was found - palladium gold or porpecite. In appearance, this mineral is very difficult to distinguish from pure gold, because it contains only 10% palladium.

About a third of the minerals containing palladium are little studied, some of them do not even have a name, this is due to the fact that the minerals of all platinum metals form microinclusions in ores and are difficult to study. One such mineral is allopalladium. This silvery-white mineral with a metallic sheen is very rare. All components of this mineral have not yet been fully identified, however, spectral analysis showed the content of mercury, platinum, ruthenium and copper in it. The most famous palladium minerals are palladite PdO, stannopalladite Pd3Sn2, stibiopalladite Pd3Sb (contains PtAs2 impurities), braggite (Pd, Pt, Ni) S (16-20% palladium), tarite PdHg. The last of these minerals was found back in 1925 in the diamond placers of British Guinea. Its composition was established by conventional chemical analysis: 34.8% Pd and 65.2% Hg.

The largest placer deposits of platinum metals (including palladium) are located in Russia - in the Urals. Other palladium-rich countries include the United States (Alaska), Colombia and Australia.

However, the main supplier of the forty-sixth element was the deposits of nickel and copper sulfide ores, in which palladium is a by-product of processing. After all, its content in such ores is three times greater than that of platinum itself, not to mention its other satellites. Large deposits of such ores are located in Africa (Transvaal) and Canada. In our country, the richest deposits of copper-nickel ores are located in the Arctic (Norilsk, Talnakh).

Palladium is found not only in the bowels of our planet, as evidenced by the chemical analysis of space "guests". So, in iron meteorites, up to 7.7 grams of palladium per ton of substance, and in stone - up to 3.5 grams. And on the Sun, it was discovered simultaneously with helium back in 1868.

It is not surprising that, having the richest reserves of platinum metal ores, Russia is one of the world's largest producers and exporters of palladium, as well as platinum, nickel and copper. Leadership in this area among Russian companies belongs to MMC Norilsk Nickel. Enterprises owned by the company are mining valuable metals on the Taimyr and Kola Peninsulas. The development of deposits in the Krasnoyarsk Territory is underway. It is believed that the deposit of the Taimyr Peninsula is one of the richest in the world in terms of palladium content in sulfide ores. For this reason, Norilsk Nickel is the owner of the largest palladium reserves in the world.

Application

Another very valuable property of palladium is its relatively low price. So in the late sixties of the last century, it cost about five times less than platinum. Over time, the price of the forty-sixth element rose, but so did the prices of other precious metals. It is this quality of palladium that makes it the most promising of all platinum metals, expanding the scope of its use.

Palladium, like other platinum metals, is an excellent catalyst. In its presence, many practically important reactions begin and proceed at low temperatures, for example, the processes of fat hydrogenation and oil cracking. Palladium accelerates the hydrogenation processes of many organic products much better than such a proven catalyst as nickel. The forty-sixth element is used as a catalyst in the production of acetylene, many pharmaceuticals, sulfuric, nitric, acetic acids, fertilizers, explosives, ammonia, chlorine, caustic soda and other products of organic synthesis.

In chemical production equipment, a palladium catalyst is most often used in the form of "niello" (in a finely dispersed state, palladium, like all platinum metals, becomes black) or in the form of PdO oxide (in hydrogenation apparatuses). Since the seventies of the XX century, palladium has been actively used by the automotive industry in catalysts for afterburning exhaust gases (neutralizers). By the way, neutralizers are necessary not only for cleaning car exhaust gases, but also for cleaning any gas emissions, for example, at thermal power plants. Industrial installations of this purpose are used in the USA, some EU countries and Japan.

Due to the fact that hydrogen actively diffuses through palladium, the latter is used for deep purification of hydrogen. Under low pressure, the gas is passed through palladium tubes closed on one side, heated to 600 ° C. Hydrogen quickly passes through palladium, and impurities (water vapor, hydrocarbons, oxygen, nitrogen) are retained in the tubes. To reduce the cost of the process, not pure palladium is used, but its alloys with other metals (silver, yttrium).

Palladium and alloys based on it are widely used in electronics - for coatings resistant to sulfides. A certain amount of this metal is used for the production of high-precision precision resistance rheochords (aerospace and military equipment), including in the form of an alloy with tungsten (for example, PdV-20M). In its pure form, palladium is found in ceramic capacitors with high temperature stability, which are used in the production of pagers, mobile phones, computers, wide-screen TVs and other electronic devices. Palladium chloride PdCl2 is used as an activating agent in the galvanic metallization of dielectrics - in particular, the deposition of copper on the surface of laminated plastics in the production of printed circuit boards in electronics.

The forty-sixth element is also needed in jewelry, both as a component of alloys and by itself. For example, the well-known concept of "white gold" refers to an alloy of gold, palladium and some other elements. For example, "white gold" of the 583rd test contains 13% palladium, and the white precious metal of the 750th test has the following composition: Au - 75%, Ag - 4%, Pd - 21% (for this sample, the composition may vary). "Pure" palladium jewelry contains an admixture of ruthenium of 5%.

Palladium is used for the manufacture of special chemical glassware (for example, for the production of hydrofluoric acid) - stills, vessels, pump parts, retorts. Part of the metal is spent on the manufacture of corrosion-resistant parts of high-precision measuring instruments.

In the glass industry, palladium alloys are used in crucibles for melting glass, in spinnerets for the production of rayon and viscose thread.

Palladium and its alloys are also used in medicine - the manufacture of medical instruments, parts of pacemakers, dentures. In some countries, a small amount of palladium is used to obtain cytostatic drugs - in the form of complex compounds, similar to cisplatin.

Production

We know that William Hyde Wollaston isolated palladium while studying the latest methods of refining platinum. Dissolving raw platinum in aqua regia and precipitating only pure noble metal from the solution with ammonia, the chemist noted the unusual pink color of the solution. A color of this kind could not be explained by the presence of known impurities in raw platinum, from which Wollaston concluded that some platinum metals were present in samples of the ore he studied.

Having acted on the resulting solution of an unusual color with zinc, the English chemist obtained a black precipitate, which he dried and tried to re-dissolve in aqua regia. However, not all of the powder was dissolved. Diluting this solution with water and adding potassium cyanide (in order to avoid the precipitation of small amounts of platinum remaining in the solution), William Wollaston obtained an orange precipitate, which turned gray when heated, and when fused turned into a drop of metal, which the scientist tried to dissolve in nitric acid. The soluble part was palladium.

In such a complex and obscure language, the scientist himself described the discovery of a new metal. Modern methods for obtaining pure palladium from natural raw materials, based on the separation of chemical compounds of platinum metals, are very complex and time consuming. Most refining firms and corporations are reluctant to share their trade secrets. We can only say that the production of palladium is one of the stages in the processing of raw platinum and the production of platinum metals. The metal is obtained according to the following scheme: from the filtrate remaining after precipitation of (NH4)2, as a result of refining, a sparingly soluble complex compound dichlorodiammine palladium Cl2 is obtained, it is purified from impurities of other metals by recrystallization from a solution of NH4Cl. By calcining this compound in a reducing atmosphere of hydrogen, palladium is obtained in the form of a sponge:

Cl2 + H2 → Pd + 2NH3 + 2HCl

Sponge palladium is alloyed in a high frequency vacuum electric furnace. By reducing solutions of palladium salts, fine-crystalline palladium is obtained - palladium black. The electrodeposition of palladium is carried out from nitrite and phosphate acid electrolytes, in particular using Na2.

Other refining methods are also used, in particular, based on the use of ion exchangers.

It is known that in the mid-eighties of the last century, the annual mining and production of palladium in Western and developing countries was about 25-30 tons. No more than ten percent was obtained from recycled palladium. At the same time, the USSR accounted for up to two-thirds of the total world production of the precious metal. In our time (according to 2007 data), palladium production amounted to 267 tons, of which Russia accounted for 141 tons, South Africa - 86 tons, the USA and Canada - 31 tons, other countries - 9 tons. These statistics show that production, as well as the extraction of the forty-sixth element, is increasing, and the role of the leader still remains with our country.

Palladium products are mainly produced by stamping and cold rolling. From this metal, it is quite easy to obtain seamless pipes of the desired length and diameter. In addition, palladium is produced in ingots of 3000-3500 grams, as well as in the form of ribbons, strips, foils, wires and other semi-finished products.

The metals trading market is seeing a surge in demand for palladium. It is possible that in the near future the existing supply on the market will no longer be enough to meet the growing demand for the metal, as a result of which the price of palladium will rise even higher. Thus, palladium becomes the best investment among precious metals.

Physical properties

Palladium is a noble platinum metal of silver-white color with a face-centered cubic lattice of the copper type (a = 0.38902 nm, z = 4). Included in the first triad of platinoids, palladium, nevertheless, in appearance is more similar to silver than to platinum. At the same time, all three metals are outwardly very similar, which cannot be said about their density. In this aspect, palladium (density 12.02 g/cm3) is much closer to silver (10.49 g/cm3) than to platinum (21.5 g/cm3).

In addition to the fact that the forty-sixth element is the lightest of the platinum metals, it is also the most fusible of them - the melting point of Pd is 1,552 ° C, while the melting point of platinum (Pt) is 1,769 ° C, the melting point of rhodium ( Rh) 1960 °C, the melting point of ruthenium (Ru) is 2250 °C, for iridium (Ir) the melting point is 2410 °C, and the melting point of osmium (Os) exceeds 3000 °C. The same situation is with the boiling point of platinum metals - the lowest is for palladium (3980 °C), for rhodium and platinum about 4500 °C, for ruthenium about 4900 °C, and for iridium (5300 °C) and osmium (5,500 °C) the highest boiling points of all platinoids.

Other temperature characteristics of the forty-sixth element: heat capacity (at a temperature of 0 ° C) 0.058 cal / (g ∙ ° C) or 0.243 kJ / (kg ∙ K); thermal conductivity 0.17 cal/(cm∙sec∙°C) or 71 W/(m∙K). The linear coefficient of thermal expansion at 0 °C is 11.67∙10-6.

The similarity of the appearance of palladium with silver and platinum, its ability to polish well, resistance to corrosion and, as a result, the absence of tarnish - all these qualities made the forty-sixth element one of the jewelry metals. In a palladium frame, precious stones stand out effectively. Watches in white gold cases are very popular. It would seem, where does palladium? The fact is, “white gold” for watch cases is gold that has been decolorized with the addition of palladium. The property of palladium to "bleach" large amounts of gold is well known. Other metals also benefit from palladium. So its addition to titanium (less than 1%) is able to turn this metal into an alloy that is absolutely resistant to aggressive environments. Pure titanium is able to resist aqua regia and nitric acid, but is unstable to concentrated hydrochloric and sulfuric acids. Alloyed with palladium, titanium calmly endures their impact.

Like platinum, palladium is a ductile and malleable metal that can be welded, rolled, drawn, stamped and drawn even at room temperature. For heated palladium, these qualities improve, it is possible to obtain the thinnest sheets, wire, seamless pipes of the required length and diameter from it. Brinell hardness 49 kgf/mm2. The modulus of normal elasticity for the forty-sixth element is 12600 kgf/mm2. Relative elongation at break 24-30%. Tensile strength 18.5 kgf/mm2. It is noteworthy that the mechanical characteristics of palladium are not constant, which is important for technology. So after cold working, the hardness of this metal increases by 2-2.5 times, but decreases after annealing. Additives of related metals also affect the properties of palladium: the addition of 4% ruthenium and 1% rhodium doubles the tensile strength!

Like all platinum metals, palladium is paramagnetic, its magnetic susceptibility χs∙10-6 (at a temperature of 18 °C) is 5.4 electromagnetic units. The electrical resistivity at 0 °C is 10 Ohm∙cm∙10-6. Palladium has a unique ability to absorb hydrogen: in one volume of palladium, under normal conditions, more than eight hundred volumes of hydrogen are dissolved. In this case, the element retains a metallic appearance, but cracks and becomes brittle.

Chemical properties

Before describing the chemical properties of palladium, it is necessary to mention that this is the only element with an extremely filled outer electron shell: there are 18 electrons in the outer orbit of the palladium atom. What is the importance of this fact? The fact is that with such a structure, the atom simply cannot but have the highest chemical resistance. Therefore, even the all-destroying fluorine does not affect palladium under normal conditions. In compounds, palladium is divalent, trivalent, and tetravalent, most often divalent. At the same time, the forty-sixth element is the most active of the platinum metals, close in chemical properties to platinum. In air, palladium is stable up to a temperature of 300-350 °C, after which it begins to oxidize with oxygen, forming a dull film of palladium oxide PdO on the surface:

2Pd + O2 → 2PdO

Interestingly, palladium oxide PdO decomposes into metal and oxygen after “passing” the threshold of 850 °C, and at this temperature, metallic palladium becomes resistant to oxidation again.

Palladium does not react with water, dilute acids, alkalis, ammonia hydrate. This is due to the position of the forty-sixth element in the series of standard potentials, where it is located to the right of hydrogen. But palladium interacts with concentrated sulfuric and nitric acids, dissolves in aqua regia:

Pd + 2H2SO4 → PdSO4 + SO2 + 2H2O

Pd + 4HNO3 → Pd(NO3)2 + 2NO2+ 2H2O

3Pd + 4HNO3 + 18HCl → 3H2 + 4NO + 8H2O,

and also goes into solution upon anodic dissolution in hydrochloric acid. When dissolved in aqua regia, palladium forms hexachloropalladic (IV) acid H2, which decomposes upon boiling to H2 and Cl2.

At room temperature, palladium reacts with wet bromine and chlorine:

Pd + Cl2 → PdCl2

Palladium dichloride PdCl2 - red crystals, easily soluble in water and hydrochloric acid. Moreover, as a result of the last reaction, tetrachloropalladic (II) acid H2 is obtained.

At temperatures of 500 ° C and above, the forty-sixth element can interact with fluorine and other strong oxidizing agents, as well as with sulfur, selenium, tellurium, arsenic and silicon.

The interaction of palladium with hydrogen is very interesting - the metal is able to absorb a large amount of this gas (at room temperature, one volume of palladium absorbs up to 950 volumes of hydrogen) due to the formation of solid solutions with an increase in the crystal lattice parameter. Hydrogen is found in the metal in atomic form and has a high chemical activity. The absorption of a large volume of hydrogen does not pass without a trace for palladium - the metal swells, swells, and cracks. The absorbed gas is easily removed from palladium when heated to 100°C in vacuum.

In addition to absorbing hydrogen, palladium has the property of transit of this gas through itself. So, if hydrogen is pumped under pressure into a vessel made of palladium, and then the sealed container is heated, then hydrogen will “flow out” from the palladium vessel through the walls, like water through a sieve. At 240°C, 40 cubic centimeters of hydrogen pass through every square centimeter of a millimeter-thick palladium plate in one minute, and as the temperature rises, the permeability of the metal becomes even more significant.

Like all platinum metals, palladium forms many complex compounds. Complexes of bivalent palladium with amines, oximes, thiourea, and many other organic compounds have a planar square structure and this differs from the complex compounds of other platinoids. Those almost always form bulky octahedral complexes. Modern science knows more than one thousand complex compounds of palladium. Some of them are of practical use - at least in the production of palladium itself.

Banking analysts write about the insufficient satisfaction of demand for palladium - and after all, industry, medicine, and the jewelry industry need the precious metal.

Meanwhile, according to scientists, every year almost a palladium shower falls on the surface of our planet. Well, maybe not a downpour, but the faithful seven kilograms arrive from space every year!

Where does such wealth come from?

We are the children of the stars...

... and in the literal sense, and most of the body. More - because some of the chemical elements that make up both human and celestial bodies were formed outside the stars. Palladium is the “son” of two processes occurring in the Universe at once. Some of it is synthesized in reactions that take place in massive stars. Part of the palladium, as well as the rest, is formed during supernova explosions.

The metal ejected into interstellar space sooner or later becomes part of a gas and dust cloud, from the mass of which stars and planets condense. Colliding and colliding, celestial bodies are crushed - these are the fragments that the Earth collects in its journey through the orbits of the galaxy. The aforementioned seven kilograms of palladium are contained in two thousand tons of meteorites that fall on our planet per year ...

A considerable amount of palladium is concentrated in the burnable nuclear fuel of nuclear power plants. For obvious reasons, it is impossible to use metal from uranium-plutonium slag in any way. So right away - you can’t, but after 10-15 million years (quite a bit by the standards of the Universe) - you can!

Two centuries since the discovery of palladium

The honor of discovering palladium belongs to a not too diligent English doctor, who showed remarkable research insight and excellent commercial resourcefulness.

William Wollaston, at that time already a full member of the London Royal Society for the Knowledge of Nature, in the last years of the 18th century started a profitable business for the production of platinum tableware. Experimenting with the ore residue, Wollaston allocates new metals, one of which the scientist gives the name "palladium", and the second - "rhodium".

The name palladium is rather accidental. In the early 1800s, the Greek goddess Pallas Athena was famous for her name given to a recently discovered asteroid. In 1803, two years after the momentous event, Wollaston gave the "new silver" the fashionable name of a wise warrior.

Richard the unbeliever

At the beginning of the 19th century, science served as entertainment for many enlightened people. Not without a slight hoax and Wollaston. The announcement he gave read: a noble metal has been discovered, similar in appearance and properties to m. Offered for purchase...

The ambitious Irish chemist Richard Cheneviks, who had just received the highest award of the Royal Society, decided to turn his success into a triumph, and publicly promised to bring the fraudster to clean water. According to Cheneviks, the unknown charlatan simply used the little-known Musin-Pushkin method, which made it possible to fuse mercury with platinum.

Having redeemed the ingot that was being sold, Chenevix hastily conducted research, and soon reported at a meeting of the academic council about his own correctness. It remains only to expose the forger!

And then an announcement appears in the newspaper: someone promises to pay 20 pounds to anyone who can fuse platinum with mercury so that “new silver” is obtained ...

With rage turning into frenzy, Chenevix begins the experiments. At the same time, other chemists in London are working with him. Needless to say, none of them manage to either synthesize palladium or isolate platinum and mercury from the ingot bought by Chenevix.

A year after the start of the epic, Wollaston gives a detailed account of the discovery. Soon he was elected president of the Royal Society. Richard Chenevix has to quit chemistry...

Extraction and use of palladium

Today, geologists count three dozen minerals that include palladium. A considerable amount of metal is included in the native formations of gold, silver and platinum. There is almost half of palladium in Norilsk platinum! Brazilian prospectors have found gold nuggets with a ten percent content of the noble metal.

Deposits of palladium ores, as a rule, coincide with deposits of other non-ferrous metals, including nickel, mercury, and copper. According to modern estimates, the most promising palladium reserves are concentrated in Norilsk.

amazing properties of palladium made it indispensable in the chemical industry. The ability of palladium to absorb hydrogen in a volume of almost a thousand times the volume of the metal is amazing! The use of palladium catalysts in the technological cycle of margarine production made it possible to abandon the previously inevitable contamination of the food product with nickel.

Hot palladium is easily permeable to hydrogen. A millimeter-thick metal plate installed as a membrane removes hydrogen from complex gas compositions and solutions that do not otherwise release hydrogen.

Palladium alloys do not oxidize even under an electric arc which paved the way for them into the electrical industry. Titanium with a small addition of palladium exhibits properties of increased resistance to a variety of chemical stresses. Medicine cannot do without palladium: the metal is used in dentistry, cardiology, and pharmaceuticals.

Palladium in jewelry

By itself, palladium is very decorative and can compete in expressiveness with silver, and even more so with platinum. Alloys containing palladium are highly valued by jewelers.
The so-called "" is most often nothing more than a combination of gold and palladium. The soft, discreet luster of precious metal is the best frame for! An alloy of palladium with indium - depending on the concentration of the ingredients - can have a color from a characteristic golden to a pronounced lilac hue.

Wedding rings made of an alloy with a high content of palladium (palladium samples - 500, 850, ligature - silver) are visually indistinguishable from rhodium-plated gold rings. At the same time, the owner of the jewelry does not need to periodically renew the rhodium plating. And the price of palladium is somewhat inferior to gold.

The addition of palladium to platinum makes the product more expressive and improves the technological properties of the material.

Palladium is one of the elements of the periodic table, which is part of the platinum group.

The history of the discovery of palladium and its occurrence in nature, biological, chemical and physical properties of palladium, the use of palladium in the jewelry industry, investment in palladium, production of palladium, facts about palladium

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Palladium is, definition

Palladium is extremely heavy and very refractory ductile and malleable metal, which is very easily rolled into foil and drawn into a thin wire. In terms of density, which is 12 g/cm3, palladium is still closer to silver, whose density is 10.5 g/cm3, than to related platinum (21 g/cm3). Palladium occurring in nature consists of six stable isotopes: 102Pd (1.00%), 104Pd (11%), 105Pd (22%), 106Pd (27%), 108Pd (26%) and 110Pd (11%). The longest-lived and artificial radioactive isotope is 107Pd with a half-life of more than seven million years. Many isotopes of palladium are produced in small amounts in the fission of uranium and plutonium nuclei. In modern nuclear reactors, 1 ton of nuclear fuel with a burnup of 3% contains about 1.5 kilograms of palladium.

Palladium is one of the elements of the periodic table of chem. elements named after Mendeleev. In the table, this element has a serial number 46 and is located in the fifth period of the elements.

Palladium is noble to metals belonging to the platinum group. By itself it has a white - silver color.

Palladium is the only chemical element with an extremely filled outer electron shell. There are 18 electrons in the outer orbit of the palladium atom.

Paladin is an element that is often used in the production of white gold or as the base of a palladium alloy. Even 1-2% palladium is enough to give gold a silvery white hue. But most often white gold 583 contains 13% palladium. It is most suitable for setting diamonds.

Palladium is an element capable of enhancing the anticorrosion properties of even such a metal resistant to aggressive environments as titanium. The addition of palladium in just 1% increases the resistance of titanium to sulfuric and hydrochloric acids.

Paladin is the material from which most of the medals awarded to outstanding scientists, as well as athletes, are made.

The history of the discovery of palladium

Such an interesting and extraordinary person was William Hyde Wollaston - a little-known London doctor and a world famous chemist - the discoverer of palladium and rhodium.

Finding palladium in nature

The largest placer deposits of platinum metals (including palladium) are located in Russia - in the Urals. Other palladium-rich countries include the United States (Alaska), Colombia and Australia.

Biological properties of palladium

Interestingly, palladium oxide PdO decomposes into metal and oxygen after “passing” the threshold of 850 °C, and at this temperature, metallic palladium becomes resistant to oxidation again.

Palladium does not react with water, dilute acids, alkalis, ammonia hydrate. This is due to the position of the forty-sixth element in the series of standard potentials, where it is located to the right of hydrogen. At room temperature, palladium reacts with wet bromine and chlorine.

At temperatures of 500 ° C and above, the forty-sixth element can interact with fluorine and other strong oxidizing agents, as well as with sulfur, selenium, tellurium, arsenic and silicon.

The use of palladium in the electronics industry

The use of palladium in everyday life

In the glass industry, palladium alloys are used in crucibles for melting glass, in spinnerets for the production of rayon and viscose thread.

The use of palladium in medicine

The use of palladium in the jewelry industry

Palladium is beautiful in its own way, perfectly polished, does not tarnish and is not subject to corrosion. In a palladium setting, precious stones, especially diamonds, stand out spectacularly. Today, palladium and white gold jewelry is very popular. Here, “white gold” must be understood in the truest sense of the word: it is gold that has been decolorized by the addition of palladium. Palladium is able to "whiten" almost six times the amount of gold.

Palladium is not often seen as a base for jewelry - this precious metal is used as a component of various jewelry alloys. It is often used in the production of white gold or as the basis for a palladium alloy. The fact is that even 1-2% of palladium is enough for gold to acquire a silvery-white hue (nickel additive provides a yellowish color, and rhodium gives a slight blueness). But most often white gold 583 contains 13% palladium. It is the best fit for setting diamonds.

And when added to platinum, palladium provides plasticity to the metal. The metal itself is too soft to be used in its pure form. Therefore, alloys are the most optimal solution for this noble metal, however, as well as for the rest.

In nature, palladium is found together with platinum - it can be extracted using a special technology. In appearance, palladium resembles silver. In 1803, it was called "new silver" because of its silvery hue. However, this is where the similarity ends - the chemical and physical-mechanical properties of silver and palladium differ like heaven and earth. Although palladium does not oxidize in air and is not exposed to external factors, it is easily soluble in nitric and sulfuric acids. In general, its extraordinary malleability can be noted - from one gram of palladium you can stretch the longest wire and roll out the thinnest sheet.

Therefore, plastic palladium has found application in the electronics industry, and in instrument making, and, of course, in the jewelry industry. On world markets, palladium is quoted along with gold, silver and platinum.

In the manufacture of jewelry, not pure palladium is used, but its alloy with various chemical elements, the most common of which are nickel, cobalt and ruthenium. The Government of the Russian Federation has officially set 500 and 850 samples of palladium. These are the most common types of samples that most jewelry has.

In addition, 950 assay is very popular, from which wedding rings are often made, as an alternative to white gold with rhodium plating. Rhodium quickly wears off with constant contact with the skin of the hands, and going to a jewelry workshop every year to renew the coating is not acceptable for everyone. Palladium rings have exactly the same appearance as gold rings, but they do not need to be processed annually.

The use of palladium as money

Their release was completed several years ago and did not last long, so these coins have a high collectible value. Of greatest interest is the series “The first Russian trip around the world. 1803-1806 "-" Sloop "Hope"" with a portrait of I.F. Kruzenshtern, “The Neva Sloop (Yu.F. Lisyansky)” and the series “The First Russian Antarctic Expedition. 1819-1821 "-" Sloop "Mirny" (M.P. Lazarev)", "Sloop" Vostok "(F.F. Bellingshausen)". The minting quality is “proof”, the content of pure metal in the coin is 31.1 g, the face value is 25 rubles, issued in 1993-94. Also presented are coins of the series "Russia and World Culture" - "A. Rublev", "M.P. Mussorgsky”, coins of the “Russian Ballet” series and dedicated to Russian monarchs. Quantity is limited. In addition to being rare, palladium coins can serve as a gaming investment tool - since 1997, palladium prices on the world market have ranged from $150 to $1,000 per troy ounce.

A quarter of a century later, the following message appeared in the Mining Journal, published in Russia: “In 1822, G. Brean was instructed by the Spanish government to purify and turn into ingots all the platinum collected in America for many years. On this occasion, processing more than 61 pounds of raw platinum, he separated two and a quarter pounds of palladium, a metal discovered by Wollaston and, due to its extreme rarity, is valued five and a half times higher than gold.

Today, when the content of all elements in the earth's crust has been calculated with relative accuracy, it is known that it contains about ten times more palladium than gold. However, the total reserves of palladium, like other metals of the platinum group, are rather scarce - only 5-10 - 6%, although geochemists can name about 30 minerals that include this element. Unlike other platinoids, palladium, like platinum itself, also occurs in its native state. As a rule, while it contains impurities of platinum, iridium, gold, silver. Often, palladium itself is found in nature as an admixture to native platinum or gold. In Brazil, for example, found the rarest variety of native gold (porpezite), which contains 8 - 11% palladium.

Since placer deposits of palladium are quite rare, the main raw materials for its production are nickel and copper sulfide ores. Palladium, however, plays a modest role as a by-product of ore processing, but this does not make it any less valuable. Transvaal and Canada have large deposits of such ores. And relatively recently, Soviet geologists found in the Norilsk region extensive deposits of copper-nickel ores, which are characterized by the presence of platinum metals, mainly palladium.

This element is present not only on our planet - it is also found on other celestial bodies, as evidenced by the composition of meteorites. So, in iron meteorites, up to 7.7 grams of palladium per ton of substance, and in stone - up to 3.5 grams. Everyone knows that there are spots on the Sun. But what's in the sun

there is palladium, apparently not everyone knows. Scientists discovered palladium there at the same time as helium, back in 1868.

Despite the fact that palladium is about one and a half times heavier than iron, among its "colleagues" -platinoids, it has a reputation for being lightweight: in terms of density. (12 g / cm3) it is significantly inferior to osmium (22.5), iridium (22.4), platinum (21.45). It also melts at a lower temperature (1552° C) than other platinum group metals. Palladium is easily processed even at room temperature. And since it is quite beautiful, polishes well, does not tarnish or corrode, jewelers willingly took it to work: they make frames for precious stones from it, for example.

We are already accustomed to such newspaper stamps as "black gold" - this is how they call oil, "soft gold" - fur, "green gold" - forest. When people talk about "white gold", they usually mean cotton. But it turns out that gold can be white in the most literal sense: even small additions of palladium remove the yellowness “from the face” of gold and give it a beautiful white hue. Watches, settings for precious stones, bracelets made of white gold are very spectacular.

Acquaintance with palladium for titanium also turned out to be very pleasant. It is known that this metal is characterized by high corrosion resistance: even such omnivorous "predators" as aqua regia or nitric acid cannot "feast on" titanium, however, under the action of concentrated hydrochloric and sulfuric acids, it is still forced to correlate. But if it is slightly “fortified” with palladium (the addition is less than 1%), then the ability of titanium to resist these oxidizing agents increases dramatically. Such an alloy has already been mastered by our factories: it is used to manufacture equipment for the chemical, nuclear, and oil industries. During a year of exposure to hydrochloric acid, a plate made of a new alloy loses only 0.1 millimeters of its thickness, while pure titanium “looses” by 19 millimeters over the same period. A solution of calcium chloride alloy is not at all tough, and titanium without an admixture of palladium has to pay an annual tribute to this aggressor - more than two millimeters.

How does palladium manage to have such a beneficial effect on titanium? The reason for this was the phenomenon recently discovered by scientists of the so-called self-passivation (self-protection) of metals: if literally microdoses of noble metals - palladium, ruthenium, platinum are introduced into alloys based on titanium, iron, chromium or lead, then the resistance of alloys against corrosion increases by hundreds, thousands and even tens of thousands of times.

In the alloy corrosion laboratory of the Institute of Physical Chemistry, scientists tested the effect of palladium on chromium steel. Parts made of this material are corroded by many acids in a few days. The fact is that positive metal ions pass into the acid solution, and hydrogen ions penetrate from the solution into the crystal lattice of the metal, which readily combine with free electrons. The resulting hydrogen is released and destroys the steel. When a part made of the same steel, but with a “homeopathic” addition of palladium (a fraction of a percent), was immersed in acid, the corrosion of the metal lasted only ... a few seconds, and then the acid turned out to be powerless. The study showed that the acid interacts primarily with palladium and immediately the surface of the steel is covered with the thinnest oxide film - the part, as it were, puts on a protective shirt. Such "armor" makes steel practically invulnerable: the rate of its corrosion in boiling sulfuric acid does not exceed tenths of a millimeter per year (previously it reached several centimeters).

Palladium itself also easily falls under the influence of some other elements: it is worth introducing into it, for example, a small amount of related metals - ruthenium (4%) and rhodium (1%), as its tensile strength is approximately doubled.

Alloys of palladium with other metals (mainly silver) are used in dental technology - they make excellent prostheses from it. Palladium covers especially critical contacts of electronic equipment, telephones and other electrical devices. From palladium, spinnerets are made - caps with many tiny holes; in the production of the finest wire or artificial fibers, a specially prepared mass is pressed through these holes. Palladium serves as a material for thermocouples and some medical instruments.

But perhaps of greatest interest are the unique chemical properties of palladium. Unlike all elements known to science today, it has 18 electrons in the outer orbit of the atom; in other words, its outer electron shell is filled to the limit. Such a structure of the atom determined the exceptional chemical resistance of palladium: even the all-destroying fluorine, under normal conditions, is no more dangerous for it than a mosquito bite for an elephant. Only by calling for help at high temperatures (500 ° C or more), fluorine and other strong oxidizing agents can interact with palladium. Palladium is able to absorb or, in the language of physicists and chemists, occlude in large quantities some gases, mainly hydrogen. At room temperature, a cubic centimeter of palladium can absorb about 800 "cubes" of hydrogen. Of course, such experiments do not go unnoticed for the metal: it swells, swells, and cracks.

No less surprising is another property of palladium, also associated with hydrogen. If, for example, a vessel is made of palladium and filled with hydrogen, and then, after plugging it, heated, the gas will calmly begin to flow through ... the walls of the vessel, like water through a sieve. At 240°C, 40 cubic centimeters of hydrogen pass through each square centimeter of a millimeter-thick palladium plate in one minute, and with increasing temperature, the permeability of the metal becomes even more significant.

Like other platinum metals, palladium serves as an excellent catalyst. This property, combined with the ability to pass hydrogen, underlies the phenomenon recently discovered by a group of Moscow chemists. We are talking about the so-called conjugation (mutual acceleration) of two reactions on one catalyst, which is palladium. In this case, the reactions seem to help each other, and the substances taking part in them do not mix.

Imagine an apparatus hermetically divided by a thin palladium partition (membrane) into two chambers. One contains butylene, the other contains benzene. Palladium, greedy for hydrogen, pulls it out of butylene molecules, the gas passes through the membrane into another chamber and there it willingly combines with benzene molecules. Butylene, from which hydrogen has been taken away, turns into butadiene (raw material for the production of synthetic rubber), and benzene, having absorbed hydrogen, becomes cyclohexane (capron and nylon are made from it). The addition of hydrogen to benzene proceeds with the release of heat; This means that in order for the reaction not to stop, heat must be removed all the time. But butylene is ready to give up its hydrogen only "in exchange" for a certain number of joules. Since both reactions take place "under the same roof", all the heat generated in the first chamber is immediately used in the other. The effective combination of these chemical and physical processes is made possible by a thin palladium plate.

With the help of membrane palladium catalysts it is also possible to obtain ultrapure hydrogen from petroleum feedstock and associated gases, which is necessary, for example, for the production of semiconductors and high-purity metals.

These days, palladium is relatively cheap - its price is five times less than platinum. An important circumstance! It allows us to hope that there will be more and more work for this metal every year. And electronic computers will help him find new areas of activity. Solving such problems is up to the computer, of course, provided that scientists provide them with the necessary "information for reflection."

Today, no one is surprised by the fact that computers play chess, manage technological processes, translate from foreign languages, and calculate the flight paths of spacecraft. Why not make it a duty

The use of palladium in computers

Computer creation of new alloys with unique properties?

Such a problem was set before themselves several years ago by the scientists of the Institute of Metallurgy named after A. A. Baikov. First of all, they had to find a common language with the machine, on which they could give commands to it. And such a language - the necessary algorithms - scientists managed to develop. The results of studies of about 1,500 different alloys were entered into the memory block of the Minsk-22 computer, and, in addition, the "questionnaire data" of metals - the electronic structure of their atoms, melting temperatures, types of crystal lattices and many other information characteristic of each of the metals. Knowing all this, the machine had to predict which previously unknown compounds could be obtained, indicate their main properties, and therefore select suitable applications for them.

Imagine that these tasks would be solved, as before, in a "manual" way - through ordinary experiments. This would mean that to each metal it is necessary to add various amounts of another metal, chosen for one reason or another, to prepare samples from the resulting alloys, then subject them to physical and chemical studies, etc. Well, if you set yourself the goal of studying all possible combinations of not two, but three, four, five components? Such work would take tens or even hundreds of years. In addition, experiments would require a huge amount of metals, many of which are expensive and scarce. It is quite possible that the terrestrial reserves of such rare elements as, for example, rhenium, indium, palladium, would simply not be enough for such experiments.

For an electronic computer, numbers, symbols, formulas serve as food for the mind, and its “labor productivity” is higher: in a matter of moments it is able to give out huge scientific information.

As a result of painstaking work carried out under the guidance of Corresponding Member of the USSR Academy of Sciences E. M. Savitsky, it was possible first to predict with the help of a computer, and then to obtain many interesting materials in nature. One of the first compounds born by computers were palladium alloys, including an unusually beautiful lilac alloy of palladium and indium. But the main thing, of course, is not in color. The business qualities of the new "employees" are much more important. And, I must say, they are top notch. Thus, the alloy of palladium and tungsten created by the institute made it possible to increase the reliability and service life of many electronic devices by more than 20 times.

“Computer forecasting,” says E. M. Savitsky, “of course, is not done for alloys that can be obtained by simply mixing components, but where complex compounds are needed and it is required to obtain alloys that can withstand huge pressures and ultrahigh temperatures that resist magnetic and electric fields, where the help of a computer is needed. The machine has already suggested to scientists about eight hundred new superconducting compounds and almost a thousand alloys with special magnetic properties. In addition, the computer recommended metallurgists to pay attention to about five thousand compounds of rare earth metals, of which only a fifth is known so far. Valuable guidance was also received from the machine regarding transuranium elements.

According to E. M. Savitsky, “the possibilities for the synthesis of inorganic compounds are endless. Based on them, the number of obtained compounds can be increased tenfold already in the coming years. And undoubtedly among them will be substances with completely new and rare physical and chemical properties necessary for the national economy and new technology.

In conclusion, we will talk about two medals made of palladium. The first of them, bearing the name of Wollaston, was established by the London Geological Society a century and a half ago. At first, the medal was minted from gold, but after the English metallurgist Johnson extracted pure palladium from Brazilian palladium gold in 1846, it is made only from this metal. In 1943, the Wollaston medal was awarded to the remarkable Soviet scientist Academician A.E. Fersman and is now kept in the State Historical Museum of the USSR. The second palladium medal, awarded for outstanding work in the field of electrochemistry and the theory of corrosion processes, was established by the American Electrochemical Society. In 1957, this award was awarded to the works of the largest Soviet electrochemist, Academician A.I. Frumkin.

Palladium production

Sponge palladium is alloyed in a high frequency vacuum electric furnace. By reducing solutions of palladium salts, fine-crystalline palladium is obtained - palladium black.

Other refining methods are also used, in particular, based on the use of ion exchangers. It is known that in the mid-eighties of the last century, the annual extraction and production of palladium in Western and developing countries was about 25-30 tons. No more than ten percent was obtained from recycled palladium. At the same time, the USSR accounted for up to two-thirds of the total world production of the precious metal. In our time (according to 2007 data), palladium production amounted to 267 tons, of which Russia accounted for 141 tons, South Africa - 86 tons, the USA and Canada - 31 tons, other countries - 9 tons. These statistics show that production, as well as the extraction of the forty-sixth element, is increasing, and the role of the leader still remains with our country.

Palladium is a profitable investment

Since 2006, the metal trading market has seen an increase in demand for palladium. The current supply on the market may not be enough to meet the growing demand for the metal soon, pushing the price of palladium even higher. Thus, palladium becomes the best investment among precious metals.

Palladium is a platinum group metal with unique properties that are especially valuable for research and manufacturing applications. By adding palladium to titanium or chromium steel, their high corrosion resistance becomes almost absolute. From alloys with palladium, materials are made for the chemical, nuclear, and oil refining industries.

Like other platinum group metals, palladium is an excellent catalyst. This property is widely used in the automotive industry. Palladium has an amazing ability to absorb certain gases, especially hydrogen. Because of this, it is beginning to be used in the development of fuel cells for hydrogen energy. With the development of technology, the consumption of platinum and palladium has increased more than 20 times in the last half century. In addition, palladium is also very beautiful and easy to process. It resembles platinum, but weighs less, has an even bewitching brilliance. An extremely rare metal is mined from ores, which usually also contain gold, nickel, copper, and sometimes occurs in native form. The main raw material for its production is copper-nickel ores, during the processing of which palladium is a by-product.

Almost all world reserves of ores containing platinum group metals belong to Russia and South Africa, moreover, South African ores contain more platinum, and Russian ones have more palladium. There are also small amounts of palladium in the bowels of Canada, the USA, Zimbabwe, China and Finland. The largest proven reserves of palladium are located beyond the Arctic Circle. According to Norilsk Nickel, proven and probable ore reserves in deposits on the Taimyr Peninsula contain 62 million ounces of palladium and 16 million ounces of platinum. (Russia - Canada: competition in the non-ferrous metals market).

Since the 1970s, the automotive industry has become a major area of application for platinum group metals. Platinum, palladium and rhodium are used in the production of catalysts that serve to reduce the toxicity of exhaust gases. For a long time, platinum was used almost exclusively for this purpose. Catalyst manufacturers such as Johnson Matthey, who had close ties to South African mining companies, were interested in this. They deliberately didn't use the cheaper palladium - and there's not much of it in South Africa - and in doing so, they helped keep their suppliers high, while remaining virtually a monopoly themselves.

The situation began to change in 1988, when Ford Motor Company (F) mastered the production of catalysts using palladium instead of platinum. By the mid-1990s, both metals were already being used approximately equally for the production of autocatalysts. With the tightening of environmental regulations, the consumption of platinum metals continues to grow. Over the past 5 years, the world's largest automakers have increased their use of palladium in vehicle exhaust systems by 32%.

In the 1990s, palladium began to rapidly replace platinum from the industry. While in 1990 almost six times more platinum was used in the production of autocatalysts than palladium, since 1995 palladium has dominated, and in 1999 the ratio became 4 to 1 in favor of palladium. The "Palladium Decade" (1990-1999) coincided with a period of widespread use of autocatalysts throughout the world. The corresponding increase in demand for platinum metals from the automotive industry has been covered almost entirely by palladium, with relatively stable platinum usage. In physical terms, the use of PGM in autocatalysts has increased almost 4 times over 10 years, and palladium - 25 times!

In the first half of the 1990s, the increase in demand for palladium was covered by the existing production capacity, and prices were kept at the level of 100 - 150 dollars per ounce, i.e. 3-4 times lower than for platinum. But a further increase in demand led to a shortage of palladium in the market starting in 1997, which led to a significant increase in prices. In 1999, the price of palladium equaled the price of platinum, and in 2000 it became more expensive than platinum - a clear sign of the "overheating" of the market. Manufacturers of autocatalysts were forced to refocus on platinum, reducing purchases of palladium.

In recent years, the price gap between platinum and palladium has been in the range of 3.5-5 and is still very far from a normal price ratio (about 1 to 2).

Meanwhile, given the low price of palladium compared to platinum, demand for palladium from autocatalyst manufacturers is growing again. Demand for palladium for autocatalyst use increased by 0.9 tons to 142.3 tons in 2008, according to Johnson Matthey.

In the field of beauty, palladium begins to crowd out platinum. Palladium is beautiful in itself, and adds nobility to other metals: its small additions give gold a unique white hue, “white gold” serves as an excellent setting for precious stones. According to the largest trading house and jewelry manufacturer from New York Fortunoff, palladium products already account for 10% of the jewelry market. According to Johnson Matthey, palladium demand in the jewelry industry rose 1.7 tons to 24.3 tons in 2008 after falling for two years in a row. Fortunoff spokesperson Ruth Fortunoff said: “We definitely expect sales growth to continue. People don’t come specifically for palladium jewelry yet, but when they see the prices and get to know the metal, they become its fans.” The average price of a palladium engagement ring is around $600, while a ring made of platinum costs twice as much. In an era of crisis, this becomes especially relevant.

Exchange-traded funds begin to play a special role in the precious metals market. Their precious metal-backed shares are listed on the stock exchange and traded in the same way as corporate shares. Analysts believe that the new funds will increase the demand for precious metals and attract additional investment.

Indeed, the creation of new exchange-traded funds, which themselves have become active buyers of platinum, remains one of the main factors behind the significant rise in the price of platinum. Since the properties and applications of palladium and platinum largely coincide, the markets for these metals are interconnected, which means that we can expect a similar reaction of the palladium market to the activities of funds.

Such assumptions are confirmed by Stuart Flerlidzh (Stuart Flerlage) from the New York company NuWave Investment: “Prices for platinum are rising higher and higher ... Perhaps we will have the same picture with valuable palladium.” The creation of exchange-traded funds linked to the price of platinum could further spur demand for the metal, prompting more manufacturers and jewelers to turn their eyes to yet more affordable palladium, said Michael Gambardella, an analyst at JPMorgan Chase & Co. (JPM). “We expect the large price gap between the two metals to close,” adds Gambardella.

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Palladium is one of the elements of the periodic table, which is part of the platinum group.

The history of the discovery of palladium and its presence in nature, the biological, chemical and physical properties of palladium, the use of palladium in the jewelry industry, in palladium, the production of palladium, facts about palladium

Palladium is, definition

Palladium is extremely heavy and very refractory ductile and malleable, which is very easily rolled into foil and drawn into thin wire. In terms of density, which is 12 g/cm3, palladium is still closer to silver, whose density is 10.5 g/cm3, than to related platinum (21 gcm3). Palladium occurring in nature consists of six stable isotopes: 102Pd (1.00%), 104Pd (11%), 105Pd (22%), 106Pd (27%), 108Pd (26%) and 110Pd (11%). The longest-lived and artificial radioactive isotope is 107Pd with a half-life of more than seven million years. Many isotopes of palladium are produced in small amounts in the fission of uranium and plutonium nuclei. In modern nuclear reactors, 1 ton of nuclear fuel with a burnup of 3% contains about 1.5 kilograms of palladium.

Palladium (Palladium) is

Palladium is one of the elements of the periodic table of chem. elements named after Mendeleev. In the table, this element has serial number 46 and is located in the fifth period elements.

Palladium is noble metals belonging to the platinum group. By itself it has a white - silver color.

Palladium is the only chemical element with an extremely filled outer electron shell. There are 18 electrons in the outer orbit of the palladium atom.

Paladin is an element that is often used in the production of white gold or as the base of a palladium alloy. Even 1-2% palladium is enough to gold acquired a silvery-white tint. But mostly white gold 583 samples contain 13% palladium. It is most suitable for setting diamonds.

Palladium is an element that can enhance the anti-corrosion properties of even such a resistant to aggressive media metal, how . The addition of palladium in just 1% increases the resistance to sulfuric and hydrochloric acids.

Paladin is the material from which most of the medals awarded to outstanding scientists, as well as athletes, are made.

The history of the discovery of palladium

Palladium was discovered by the English physician and chemist William Wollaston in 1803 while studying raw platinum, brought from the burning continent, in that part of it that is soluble in aqua regia. Having dissolved the ore, Wollaston neutralized the acid with a solution of NaOH, after which he precipitated platinum from the solution by the action of ammonium chloride NH4Cl (ammonium chloroplatinate precipitates). Mercury cyanide was then added to the solution to form palladium cyanide. Pure palladium was isolated from cyanide by heating. Only a year later, Wollaston reported to the Royal Society that he had discovered palladium and another new noble metal, rhodium, in raw platinum. The very name of the new element - palladium (Palladium) Wollaston derived from the name of the minor planet Pallas (Pallas), discovered shortly before (1801) by the German astronomer Olbers.

The forty-sixth element, due to a number of its remarkable physical and chemical properties, has found wide application in many areas of science and life. So some types of laboratory glassware are made from palladium, as well as parts of equipment for the separation of hydrogen isotopes. Alloys of palladium with other metals find a very valuable application. For example, alloys of the forty-sixth element with silver used in communication equipment (contact manufacturing). Temperature controllers and thermocouples use alloys of palladium with gold, platinum and rhodium. Certain alloys of palladium are used in jewelry, dentistry (dentures) and even used to make parts for pacemakers.

When applied to porcelain, asbestos and other supports, palladium serves as a catalyst for a number of redox reactions, which is widely used in the synthesis of a number of organic compounds. Palladium is used to purify hydrogen from traces of oxygen, as well as oxygen from traces of hydrogen. A solution of palladium chloride is an excellent indicator of the presence of carbon monoxide in the air. Palladium coatings are applied to electrical contacts to prevent sparking and increase their corrosion resistance (palladium).

In the jewelry trade, palladium is used both as a component of alloys and by itself. In addition, the Russian Central Bank mints palladium commemorative coins in very limited quantities. A small amount of palladium is consumed for medical purposes - the preparation of cytostatic drugs - in the form of complex compounds, similar to cis-platinum.

The honor of discovering palladium belongs to the Englishman William Hyde Wollaston, who isolated a new one from the crude platinum of South American mines in 1803. Who is the man who is named after the pure palladium medal awarded annually by the Geological Society of London?

Palladium (Palladium) is

Such assumptions are confirmed by Stuart Flerlidzh (Stuart Flerlage) from the New York company NuWave Investment: “the prices for platinum are rising higher and higher ... Perhaps we will have the same picture with valuable palladium.” The creation of exchange-traded funds linked to the price of platinum could further spur demand for the metal, prompting more manufacturers and jewelers to turn their eyes to yet more affordable palladium, said Michael Gambardella, JP Morgan and Co. (JPM). “We expect the large price gap between the two metals to close,” adds Gambardella.

Sources and links

wikipedia.org - the largest free encyclopedia

helprf.com - Financial Support Center

interfax.ru - news portal

en.goldsilvermetals.com - physical metals and their properties

i-think.ru - chemical reference book and metal trade

globfin.ru - world economy, finance and investments

xumuk.ru - chemical encyclopedia

forexpf.ru - site about online trading

ru.investing.com - the largest site about investments

all-currency.ru - official foreign exchange rates

alhimik.ru - site about chemicals

chemistry-chemists.com - magazine of chemists - enthusiasts

Encyclopedia of the investor. 2013 . - I, husband. Father: Palladyevich, Palladievna and Palladyevich, Palladievna. Derivatives: Paladya; Lada (Rook); Palya; Broadsword; Pasha. Origin: (Greek Palladion palladium (the image of Pallas Athena, according to legend, fell from the sky as a guarantee of her immunity ... Dictionary of personal names

PALLADIUM- (Greek). A metal similar to silver is found in platinum ore and is used in the manufacture of astronomical and physical instruments. Dictionary of foreign words included in the Russian language. Chudinov A.N., 1910. Noble PALLADIUM ... ... Dictionary of foreign words of the Russian language

PALLADIUM- (Palladium), Pd, chemical element of group VIII of the periodic system, atomic number 46, atomic mass 106.42; refers to platinum metals, mp 1554 shC. Palladium and its alloys are used to make medical instruments, dentures, crucibles for ... ... Modern Encyclopedia

I. Palladium, Palladios, ca. 363 425 n. e., Greek Christian historian and hagiographer. Born in Galatia. After graduating in 386, he became a monk, first in Palestine, then in Egypt, from where he made numerous travels around ... ... Ancient writers

The metal is silvery white, ductile and malleable, easily rolled into foil and pulled into thin wire. Density of palladium 12.2; melting point 1552 deg. FROM; Mohs hardness 5. In air at normal temperature, palladium ... Official terminology

- (Palladium), Pd, chemical element of group VIII of the periodic system, atomic number 46, atomic mass 106.42; refers to platinum metals, mp 1554 °C. Palladium and its alloys are used to make medical instruments, dentures, crucibles for ... ... Illustrated Encyclopedic Dictionary

PALLADIUM- in Greek mythology, a small wooden statue of the goddess Athena. She was kidnapped by Odysseus and Diomedes. According to Virgil's Aeneid, the original palladium was taken by Aeneas to Italy after the fall of Troy... Big Encyclopedic Dictionary

PALLADIUM- (symbol Pd), a silvery white TRANSITION ELEMENT, a metal first discovered in 1803. Malleable, machinable palladium is found in nickel ores. Refers to platinum metals and has common chemical characteristics with PLATINUM. Not … Scientific and technical encyclopedic dictionary

A small wooden statue of the goddess Athena. She was abducted from Troy by Odysseus and Diomedes. According to Virgil's Aeneid, after the fall of Troy, genuine palladium was taken by Aeneas to Italy. (

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Palladium is one of the elements of the periodic table, which is part of the platinum group.

The history of the discovery of palladium and its occurrence in nature, biological, chemical and physical properties of palladium, the use of palladium in the jewelry industry, investment in palladium, production of palladium, facts about palladium

Palladium is, definition

The history of the discovery of palladium

Finding palladium in nature

Biological properties of palladium

The use of palladium in the electronics industry

The use of palladium in everyday life

The use of palladium in medicine

The use of palladium in the jewelry industry

The use of palladium as money

The use of palladium in computers

Palladium production

Palladium is a profitable investment

Sources and links

Palladium is one of the elements of the periodic table, which is part of the platinum group.

The history of the discovery of palladium and its presence in nature, the biological, chemical and physical properties of palladium, the use of palladium in the jewelry industry, in palladium, the production of palladium, facts about palladium

Palladium is, definition

The history of the discovery of palladium

Sources and links

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