Rhenium, the application of which we will consider below, is an element of the chemical periodic table under the atomic index 75 (Re). The name of the substance comes from the Rhine River in Germany. The year of the discovery of this metal is considered to be 1925. The first significant batch of material was obtained in 1928. This element belongs to the last analog with a stable isotope. Rhenium itself is a metal with a white tint, and its powder mass is black. The melting and boiling points range from +3186 to +5596 degrees Celsius. It has paramagnetic characteristics.
Features
The use of rhenium is not so wide because of its exceptional parameters and high cost. At +300 ° , the metal begins to undergo active oxidation, the process of which depends on a further increase in temperature. This element is more stable than tungsten, practically does not interact with hydrogen and nitrogen, providing only adsorption.
When heated, a reaction with chlorine, bromine and fluorine is noted. Rhenium does not dissolve only in nitric acid, and when reacted with mercury, an amalgam is formed. Reaction with the aqueous composition of hydrogen peroxide causes the formation of rhenic acid. This element is the only one among refractory metals that does not form carbides. The use of rhenium is not involved in biochemistry. Little information is available on its possible effects. Among the reliable facts are toxicity and toxicity for living organisms.
Production
Rhenium is a metal that is extremely rare. In nature, it is most often found in combination with tungsten and molybdenum. In addition, impurities are present in the mineral deposits of its neighbors in the table. Rhenium is predominantly mined from molybdenum deposits by means of associated extraction.
In addition, the element under consideration is mined by isolation from jazkazganite - a very rare natural mineral, which is so named after the Kazakh settlement near the deposit. Even rhenium can be distinguished from pyrites, zirconium, columbite.
Metal is dispersed throughout the world in a negligible concentration. Among the known mining sites, where it is located in significant numbers, the Kuril island of Iturup in Russia is considered. The field was discovered in 1992. Here, the metal is presented in the form of a structure similar to molybdenum (ReS 2 ).
Mining is carried out on a small site located on top of a sleeping volcano. Thermal springs are actively operating there, which indicates the expansion of the deposit, which, according to preliminary estimates, emits about 37 tons of this metal per year.
The second largest volume of production is considered to be a rhenium deposit suitable for industrial extraction of an element. It is located in Finland and is called Hitura. There, the metal is extracted from another mineral - tarcianite.
Getting
Rhenium is obtained by processing primary raw materials, which initially has a low percentage of the content of this material. Most often, the element is extracted from copper and molybdenum sulfides. Rhenium alloys are subjected to pyrometallurgical action, which is used when working with ores subjected to smelting, converting and roasting.
Excessive melting points make it possible to obtain higher oxide Re-207, which is delayed by special trapping devices. It happens that part of the element settles in soot after firing. Pure material can be obtained from this substance using hydrogen. Then, the obtained powder substance is melted directly into rhenium ingots. The use of ore for the mining of the element in question is accompanied by the appearance of sediment in matte. Further conversion of this composition makes it possible to isolate rhenium by exposure to certain gases.
Technological moments
The desired concentration during production can be achieved due to the properties of rhenium and the use of sulfuric acid. After passing through special cleaning methods, it is possible to isolate a pure element from the ore.
This method is not very productive, the yield of a pure product is not more than 65%. This indicator varies depending on the metal content in the ore. On this basis, scientific research is regularly conducted to identify more advanced and alternative methods of production.
Modern technologies make it possible to optimize the properties of rhenium obtained artificially. This solution allows you to use an aqueous solution instead of acid. This makes it possible to catch significantly more pure metal during cleaning.
Application
First, consider the main characteristics of the element in question, for which it is especially appreciated:
- Infusibility.
- Minimum susceptibility to corrosion.
- No deformation when exposed to chemicals and acids.
Since the price of this metal is extremely high, it is used mainly in rare cases. The main field of application of this element is the production of heat-resistant alloys with various metals that are used in the construction of rockets and the aviation industry. As a rule, rhenium is used to produce spare parts for supersonic fighters. Such compositions include at least 6% of the metal.
A similar source quickly turned into the main means for creating reactive power units. At the same time, the material began to be considered a strategic military reserve. Specially designed thermal pairs allow temperature measurements in vast ranges. The element under consideration makes it possible to extend the life of most aggregated metals. The springs for precision equipment, platinum metals, spectrometers, and manometers are also made from rhenium, the use of which is discussed above.
More precisely, tungsten with rhenium coating is used there. Due to its resistance to chemical influences, this metal is included in the composition of protective coatings against acid and alkaline environments.
Interesting Facts
Rhenium is also used to make special contacts. They have the property of self-cleaning in the event of a short circuit. On ordinary metals, oxide remains, preventing current from flowing. A current also passes through rhenium alloys, but it leaves no traces after itself. In this regard, contacts made of this metal have a long service life.
The most important aspect of the use of rhenium was the possibility of using it to create catalysts that help to produce certain components of gasoline fuel. The possibility of using a chemical element in the petroleum product industry led to a several-fold increase in its demand in the relevant market. The world is seriously interested in this unique material.
Stocks
It is worth noting that the global rhenium reserve is at least 13 thousand tons only in molybdenum and copper deposits. They are the main sources of this component in the metallurgical industry. More than 2/3 of all rhenium on the planet is contained in precisely such configurations. The remaining third is secondary residues. If we reduce all estimates of reserves to a single denominator, they should be enough for at least three hundred years. In the calculation of scientists, secondary use was not taken into account. Similar projects have been developed for a long time, some of them have proven their worth.
Cost
Product prices for most categories are determined by the availability and demand of the product. Such a component as rhenium belongs to one of the most expensive metals in the world, therefore it is not affordable for every manufacturer, although it has unique properties that make it possible to offset the costs of its expensive use. At the same time, rhenium possesses such parameters that no other metal possesses. For the creation of space and aircraft structures, its characteristics are ideal. It is not surprising that the price of rhenium is high, although it meets all the indicators characteristic of this unique material.
Already in 2011, the average cost of rhenium was about 4.5 US dollars per gram. In the following time, no tendency to decrease in prices was observed. Often the final cost depends on the degree of metal purification. The price of the material can reach thousands of dollars and higher.
Discovery story
This element was discovered by German chemists - Id and Walter Noddaki in 1925. They conducted research using columbispectral analysis in the laboratory of the Siemens and Shake group. After this event, a corresponding report was held at a meeting of German chemists in Nuremberg. A year later, a team of scientists isolated the first two milligrams of rhenium from molybdenum.
In a relatively pure form, the element was obtained only in 1928. To obtain one milligram of the substance, it was necessary to process over 600 kilograms of Norwegian molybdenum. Industrial production of this metal also started in Germany (1930). The capacity of the processing plants made it possible to obtain about 120 kg of metal annually. At that time, this fully satisfied the need for rhenium in the entire world market. In America, the first industrial 4.5 kg of unique metal was obtained in 1943 by processing concentrated molybdenum. It was this element that became the last open metal with a stable isotope. All other analogues discovered earlier, including by artificial means, did not have similar properties.
Natural reserves
Today, according to the natural reserves of the metal in question, the list of deposits can be arranged in the following order:
- Chilean mines.
- USA.
- Iturup Island, on which deposits are estimated up to 20 tons per year (in the form of volcanic gas eruptions).
In the Russian Federation, semi-element deposits of a hydrogenic type are estimated as sites that have the maximum potential of copper-porphyry and copper-molybdenum ores. In total, judging by the forecasts of specialists, rhenium deposits in Russia amount to 2900 tons (76% of the state’s resource). The lion's share of these deposits is in the Moscow coal basin (82%). The next field in terms of reserves is the Briquette-Zheltukhinsky basin in the Ryazan region.
Total
Rhenium is a chemical element that belongs to the group of rare metals with unique characteristics. Above described are its properties, places of production, scope.