Platinum

Platinum history

The ancient world already knew metallic platinum. During archaeological excavations in Egypt in the ruins of ancient Thebes, an artwork was found, attributed by experts to the 7th century. BC er In this relic of the ancient world there was a grain of platinum rich in iridium.

At the beginning of I century. n er Gold washers in Spain and Portugal began to show a marked 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 (the author of the 37-volume book Natural History), “white lead” was mined from the gold placers of Valiscia (North-Western Spain) and Luzitania (Portugal). Pliny tells us that “white lead” was collected during washing with gold at the bottom of the baskets and melted separately.

Long before the capture of South America by the Spanish and Portuguese conquistadors — platinum was mined by the indigenous cultural people, the Incas, who not only owned the secret of cleaning and forging this precious metal, but also knew how to skillfully craft various objects and jewelery.

The epoch of the fall of the Roman Empire is marked by the disappearance of platinum jewelers and dealers in jewelery. Many centuries passed, and only in the second half of the XVIII century. scientists began to be 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, whose brilliance somewhat resembled the brilliance of silver, but with all other qualities more resembling gold. This ulcer metal interested de Ulloa, and he brought samples of Colombian platinum to Spain.

In the XVIII century, when platinum had no industrial application, it was mixed with gold and gold and silver products. The Spanish government learned about this “damage” of precious metals. Fearing the possibility of mass forgery of the 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 requiring the destruction of all the 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 by 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. Platinum satellites — palladium, iridium, rhodium, ruthenium, and osmium — were discovered much later, in the 19th century. The six listed chemical elements in the eighth group of the periodic system of Mendeleev constitute 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 the technique, scientists were engaged in it mostly from a single curiosity, but with the 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 glassware made of platinum, it began to be used for the manufacture of distillation apparatus for sulfuric acid. From this point on, the growth in the processing of platinum began to increase dramatically, since it was used in the manufacture of acid-resistant and heat-resistant laboratory chemical equipment, tools and various instruments (crucibles, flasks, boilers, tongs, etc.).

Pyrometry uses the exceptional resistance of platinum and its alloys to high temperatures.

Valuable and sometimes irreplaceable properties of platinum and palladium have long been used in catalytic processes. A significant amount of platinum is spent on making contact for sulfuric acid plants, where it serves as a catalyst in the oxidation of sulfur dioxide to sulfuric anhydride. Platinum in the form of a grid serves as a catalyst in the oxidation of ammonia in the apparatus of various systems. Numerous organic syntheses also require the use of a platinum catalyst. Palladium catalyst is used in the production of synthetic ammonia and in the preparation of certain organic preparations. Osmium is also used in the production of synthetic ammonia according to Haber-Rosennol.

In electrical engineering, platinum metals are usually used in the form of alloys. This is not a complete list of parts of electrical devices that use platinum alloys: needles for burning out, devices for electrical measurements, electrodes (cathodes and anticathodes for X-ray tubes), wires and tapes for resistances of electric furnaces, magneto contacts (cars, internal combustion engines), contact points (telegraphy, telephony), lightning rod tips, etc.

In electrochemistry, platinum is used in the preparation of various electrolytic products. Medicine and dentistry are among the oldest users of platinum. We also note the use of platinum for surgery in the form of tips of devices used for cauterization, syringes for injection and infusion, etc.

The art of jewelery holds a leading position as a platinum consumer in the form of alloys. Platinum rims for gems give better shine and cleaner water than rims of other precious metals.

Finally, in the form of salts, platinum and its satellites are required for photography, for the manufacture of medicines (rhodium and ruthenium salts) and for the preparation of paints on porcelain (rhodium, iridium - black paint, palladium - silver).

Platinum is also used in the military segment, for example, for the manufacture of contacts that serve to produce detonation in an explosion of mines, etc.

Platinum mining

First place in the world mining of platinum belongs to the Ontario region in Canada. Here in 1856, large deposits of Sudbury copper-nickel ores were discovered, in which platinum is also present along with gold and silver.

Before World War I, Canadian platinum did not attract attention, and practical interest arose only in 1919, when, as a result of the Urals civil war, Russian platinum production dropped dramatically, and the world market began to feel a great lack of this precious metal. Since 1919, the sludge of copper-nickel production from Sudbury has been subjected to careful processing in order to extract platinum group metals, especially since the cost of mining of platinum and its satellites is very low.

The second place in the world in the extraction of platinum is Russia. Considerable amounts of platinum are mined in Colombia. From other countries producing platinum, you can specify Ethiopia and Congo. Platinum extracted directly from the subsoil, as well as platinum obtained from ores, is subjected to special treatment or refining. Refining consists of the usual processes applied on a small scale in the practice of analytical laboratories - dissolution, evaporation, filtration, precipitation, etc. As a result of these operations, pure platinum and its satellites are obtained.

World reserves of platinum and deposits of platinum in Ukraine

Almost 90% of the world's proven reserves of platinum group metals (PGM: platinum, palladium, iridium, rhodium, osmium, ruthenium) are contained in the platinum-bearing deposits of late magmatic genesis. The world resources of platinoids in the depths of more than 30 countries are estimated at 120-140 thousand tons and most of them (75-85 thousand tons) are located in the Bushveld massif of South Africa. The world production of PGM is approximately 370 tons, of which platinum is 160 tons, palladium is 180 tons.

The study of the platinum-like geological complexes of Ukraine has a half-century history - starting with the discovery in 1951 of platinum content (0.1–0.2 g / ton) in the hyperbasites of the Obitochnaya River (Western Azov). A few years later, the presence of platinum and palladium was found in rocks of a number of other areas of the Ukrainian shield and in the placers of the Dnieper-Donets depression.

Among the promising geological sites for the detection of platinum (and PGM) mineralization in Ukraine are different in composition rocks of the Ukrainian shield, the Carpathians, Volyn, Krivoy Rog and Donetsk basins, Middle Dnieper and Pobya (see the map).