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Platinum is a noble metal of silver-white color. In the periodic table, this chemical element is indicated by the sign Pt.
Platinum (Spanish Platina) - a chemical element of the 10th group (according to the outdated classification - a side subgroup of the eighth group), the 6th period of the periodic system of chemical elements of D. I. Mendeleev, with atomic number 78; brilliant noble metal of silver-white color.
The name platinum was given by the Spanish conquistadors, who in the middle of the XVI century. first met in South America (in the territory of modern Colombia) with a new metal that looks like silver (Spanish plata). The word literally means "little silver", "silver". This neglected name is explained by the exceptional refractoriness of platinum, which did not succumb to remelting, for a long time could not be used, and was valued twice as low as silver.
History of platinum
Antonio de Ulloa
The ancient world already knew metal platinum. During archaeological excavations in Egypt in the ruins of ancient Thebes, an artwork was found, attributed by specialists to the 7th century. BC e. In this relic of the ancient world was a grain rich in iridium platinum.
At the beginning of the 1st century n e. gold sands washers in Spain and Portugal began to show a noticeable interest in the beneficial use of “white lead,” or “white gold,” as platinum was then called. According to the testimony of the Roman writer Pliny the Elder (author of the 37-volume book "Natural History"), "white lead" was mined from the gold placers of Valissia (North-West Spain) and Lusitania (Portugal). Pliny says that “white lead” was collected during washing along with gold at the bottom of baskets and melted separately.
Long before the capture of South America by the Spanish and Portuguese conquistadors, platinum was mined by the cultural native people - the Incas, who not only possessed the secret of cleaning and forging this precious metal, but also knew how to skillfully craft various objects and jewelry from it.
The era of the fall of the Roman Empire is marked by the disappearance of platinum jewelers and jewelry dealers. Many centuries passed, and only in the second half of the XVIII century. scientists began to become interested in platinum and its physicochemical properties.
In 1735, the Spanish mathematician Antonio de Ulloa, while in Equatorial Colombia, drew attention to the frequent presence together with gold of an unknown metal, the luster of which somewhat resembled that of silver, but with all other qualities more like gold. This outlandish metal interested de Ulloa, and he brought samples of Colombian platinum to Spain.
In the XVIII century, when platinum had no industrial use, it was mixed with gold and gold and silver products. The Spanish government found out about this "corruption" of precious metals. Fearing the possibility of a massive fake of a gold coin, it decided to destroy all the platinum mined together with gold in the colonial possessions of the kingdom. In 1735, a decree was issued ordering the destruction of all platinum mined in Colombia. This decree was valid for several decades. Special officials in the presence of witnesses periodically threw cash reserves of platinum into the river.
At the end of the XVIII century. the Spanish kings themselves began to "spoil" the gold coin, mixing platinum with it.
Technical use of platinum
In 1752, the director of the Swedish Mint, Schaeffer, announced the discovery of a new chemical element - platinum. The satellites of platinum - palladium, iridium, rhodium, ruthenium and osmium - were discovered much later, in the XIX century. The six chemical elements listed in the eighth group of the periodic table make up a group called platinum metals. All these metals have many similar physical and chemical properties and are found in nature for the most part together.
At the dawn of the introduction of platinum in technology, scientists were engaged in it for the most part out of one curiosity, but with an in-depth study of the properties of platinum it quickly began to find wide application, especially in the chemical industry. It turned out that platinum is soluble only in aqua regia, insoluble in acids and constant during glowing.
Following the appearance of the first samples of chemical dishes made of platinum, they began to use it for the manufacture of distillation apparatus for sulfuric acid. From that moment, the growth of platinum processing began to increase sharply, as it began to be used in the production of acid-resistant and heat-resistant laboratory chemical equipment, instruments and various devices (crucibles, flasks, boilers, tongs, etc.).
In pyrometry, the exceptional resistance of platinum and its alloys to high temperatures is used.
The valuable and sometimes irreplaceable properties of platinum and palladium have long been used in catalytic processes. A significant amount of platinum is spent on the production of a contact for sulfuric acid plants, where it serves as a catalyst for the oxidation of sulfur dioxide to sulfuric anhydride. Platinum in the form of a grid serves as a catalyst for the oxidation of ammonia in devices of various systems. Numerous organic syntheses also require the use of a platinum catalyst. The palladium catalyst is used in the production of synthetic ammonia and in the preparation of certain organic preparations. In the production of synthetic ammonia according to Gaber-Rosennol, osmium is also used.
In electrical engineering, platinum metals are usually used in the form of alloys. Here is a far from complete list of parts for electric devices that use platinum alloys: needles for burning, devices for electrical measurements, electrodes (cathodes and anticathodes for X-ray tubes), wires and tapes for the resistance of electric furnaces, magneto contacts (cars, internal combustion engines), contact points (telegraphy, telephony), tips of lightning rods, etc.
In electrochemistry, platinum is used to produce various electrolytic products. Medicine and dentistry are among the oldest consumers of platinum. We also note the use of platinum for surgery in the form of tips of devices serving for cauterization, syringes for injection and infusion, etc.
Jewelry has a leading position as a consumer of platinum in the form of alloys. Platinum frames for gemstones give better shine and cleaner water than frames made of other noble metals.
Finally, in the form of salts, platinum and its companions are required for photography, for the manufacture of medicines (salts of rhodium and ruthenium) and for the preparation of paints on porcelain (rhodium, iridium - black paint, palladium - silver).
Platinum is also used in the military sector, for example, for the manufacture of contacts used to produce detonation in the explosion of mines, etc.
How platinum is mined
The first place in world platinum mining belongs to the Ontario region in Canada. Here in 1856, large deposits of copper-nickel ores of Sudbury were discovered, in which platinum is present along with gold and silver.
Before the First World War, Canadian platinum did not attract attention, and practical interest in it arose only in 1919, when, as a result of the civil war in the Urals, Russian platinum production fell sharply, and the world market began to feel a great shortage of this valuable metal. Since 1919, the Sludbury copper-nickel sludge was subjected to thorough processing in order to extract the platinum group metals, especially since the cost of producing platinum and its companions in passing is very low.
Russia takes the second place in the world in platinum mining. Significant amounts of platinum are mined in Colombia. Other platinum producing countries include Ethiopia and Congo. Platinum mined directly from the bowels, as well as platinum obtained from ores, is subjected to special processing or refining. Refining consists of the usual processes used on a small scale in the practice of analytical laboratories - dissolving, evaporating, filtering, precipitating, etc. As a result of these operations, pure platinum and separately its companions are obtained.
World reserves of platinum and deposits of platinum in Ukraine
The layout of the deposits (1) and ore occurrences (2) of gold and the manifestations of platinoids (3) in Ukraine.
Almost 90% of the world's proven reserves of platinum group metals (PGMs: platinum, palladium, iridium, rhodium, osmium, ruthenium) are contained in platinoid strata deposits of late magmatic origin. The world resources of platinoids in the bowels of more than 30 countries are estimated at 120-140 thousand tons and most of them (75-85 thousand tons) are in the Bushveld massif of South Africa. The volume of global PGM production is approximately 370 tons, of which platinum - 160 tons, palladium - 180 tons.
The study of platinum-bearing geological complexes of Ukraine has a half-century history - starting with the discovery in 1951 of the platinum content (0.1-0.2 g / ton) in the hyperbasites of the Obitnaya River (Western Azov Region). A few years later, the presence of platinum and palladium was found in the rocks of several other areas of the Ukrainian shield and in placers of the Dnieper-Donets depression.
Promising geological objects for the detection of platinum (and PGM) mineralization in Ukraine include rocks of the Ukrainian Shield, Carpathians, Volyn, Krivorozhsky and Donetsk basins, the Middle Dnieper and Pozhuzhny (see map-scheme).
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