It combines many useful physical, mechanical and technological properties that determine its application from metallurgy to the petrochemical industry. The page contains a description of this metal: physical, chemical properties, application areas, grades, and product types.
Basic information
Rhenium (Re) is a chemical element of the VII group of Mendeleev’s periodic table. Its atomic number is 75, atomic mass is 186,207. It is a dense silvery-white transition metal belonging to the group of refractory metals. It has a high density of 21.02 g/cm3, its melting point is 3186 °C, boiling point is 5596 °C. It has good strength, hardness, corrosion resistance and high specific electric resistance.
The described chemical element belongs to rare refractory metals - its content in the earth's crust is very small. In ores, it is always present together with tantalum. The main minerals are dzhezkazganite (CuReS4), rheniite (ReS2).
History of discovery
Rhenium was discovered in 1925 by German chemists IDA and Walter Noddack as a result of the study of columbite (a mineral) by spectral analysis. The first successful attempt to obtain pure Re was recorded in 1928. In 1930, its first industrial production was organized in Germany.
Rhenium properties
Physical properties
Property
Value
Atomic number
75
Atomic mass, u
186.207
Atom radius, pm
137
Density, g/cm³
21.02
Molar heat capacity, J/(K·m)
28.43
Thermal conductivity, W/(m·K)
48.0
Melting point, °C
3186
Boiling point, °C
5596
Теплота плавления, кДж/моль
34.0
Heat of evaporation, kJ/mol
704
Molar volume, cm³/mol
8.85
Group of metals
Refractory metal
Chemical properties
Property
Value
Covalent radius, pm
128
Ion radius, pm
(+7e) 53 (+4e) 72
Electronegativity (according to Pauling)
1,9
Electrode potential, V
Re←Re3+ −0,30
Oxidation degrees
+7, +6, +5, +4, +3, +2, −1
Grades of rhenium and alloys
Industrial application are mainly found in rhenium alloys, but in some cases it is necessary to use pure metal.
Re-0, Re-1 - high-purity rhenium with amounts of Re - 99.99% and 99.97% accordingly; supplied as a powder.
MR-47, MR-47 VP, MR-47 ZVP - an alloy of molybdenum with rhenium, the Re content is 42-47%; VP and ZVP indicate the production method - vacuum melting and zone vacuum melting; supplied in the form of wire, rods, flat bars and foil.
VR-5, VAR-5, VR-20, VR-27 VP, VR-27 ZVP - compound of W with 5%, 20%, 24-30% of Re accordingly; the letter A indicates the presence of silica and aluminum additives; workpieces: wire, rod.
MVR -molybdenum-tungsten-rhenium alloy with a mass fraction of Re 42-45%; semi-finished products: wire.
Advantages / disadvantages
Advantages:
it has a high melting point;
it is resistant to corrosion in many chemically aggressive environments;
it has good physical and mechanical properties - high strength and hardness, and also high specific electric resistance.
Disadvantages:
very low percentage of content in the earth's crust (one of the rarest elements);
high cost (one of the most expensive refractory metals).
Rhenium application areas
The main application areas of metal are:
measurement technologies;
metallurgy;
petrochemical industry;
electrical engineering.
Rhenium is very popular in the petrochemical industry. It is used as a catalyst. Its application has significantly improved the production of gasoline, increasing production volumes, reducing the cost of catalysts and extending their service life.
High strength and good resistance to corrosion, including at high temperatures, allow to use rhenium in electrical devices. Contacts made of Re are not subjected to oxidation and are very strong, which makes their service life significantly longer compared to copper ones.
Re is a common alloying element that can significantly improve the properties of steels and alloys containing it. Re provides alloyed materials with strength, corrosion resistance, and refractoriness.
The considered metal is also used in the production of thermoelectrodes for thermocouples - important elements of measuring devices. The high melting point of tungsten and rhenium allows to measure temperatures up to 3000 °C with these thermocouples.
Products from rhenium
Modern industrial production offers almost a full range of standard workpieces that are actively used in various areas. From round rolled products, these are rhenium wire and rod. Flat rolled products are rhenium foil and flat bar. The source raw material is rhenium powder, which occupies a fundamental place in the chain of production from this metal.
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