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Rhenium materials

Date:2017-02-22 21:53

 

Rhenium
Element symbols : Re
Elements Chinese Name: Rhenium
Element Name : Rhenium
Atomic Number: 75
Relative atomic mass: 186.207
Period: 6
The group number : VIIB
Molar mass : 186
Atomic radius: 1.97
Common valence : -1 , +1, +2 , +3, +4 , +7
Density : 21.02 g / cm 3
Melting point / ℃: 3180
Boiling point / ℃: 5627
Lattice Type: Hex -intensive
Conductivity : 0.0542 * 10 ^ 6 / (cm? Ω)
Vapor Pressure / kPa: lgp = -40865/T-1.16lgT +13.32
Specific heat capacity / J • mol-1 • K-1: cp = 23.66 +5.43 × 10-3T
Expansion coefficient (20 ℃): 6.7 × 106
Elastic modulus (20 ℃) ​​/ GPa: 460.6
Electronic work function / eV: 4.8
Standard electrode potential / V
ReO2 +4 H + +4 e = Re +2 H2O 0.252

  Rhenium is a scattered , refractory metals . Scattered refers rhenium content in the crust scarce, scattered, refractory refers to the melting point of rhenium metal is extremely high, its melting point up to 3180 ℃, second only to tungsten , ranking second in all metals . Because the catalytic activity of the compound , high temperature resistance, corrosion resistance and other outstanding features , mainly for petroleum refining catalysts , thermoelectric temperature alloy , tube structural materials , special alloys aerospace , environmental protection and other fields.

  Rhenium discovery and resource

  Rhenium is a rare metal in a truly scattered elements . It is in the crust REE content than all are small , rhenium protactinium and radium than just these elements . Plus it does not form a fixed mineral , usually associated with other metals . Which makes it exist in nature was discovered the last element .
Rhenium, manganese sub-group as a member , as early as the Mendeleev periodic system of elements , when established , had predicted its existence, it is called dwi-manganese ( Mn times ) , and put another in this family one member was also not found called eka-manganese ( Mn class ) . Later, these two elements Moseley determined the atomic number of 75 and 43 , respectively . Due to an unknown element and it can often be from a similar nature to find mineral elements , so scientists have been working from manganese , platinum, iron ore and niobium ( tantalum and niobium minerals ) to find these two elements. Until 1925 , the German W. Nuo Dake , I. Nuo Dake - Tucker and OC Berger spectrometry niobium with manganese ore discovered the element rhenium named rhenium, the word comes from the Latin Rhenus, meaning the Rhine . After Nuo Dake also found mainly in the rhenium molybdenite, and extract the metal rhenium . Rhenium due to resource -poor , expensive, long few studies . After 1950 , rhenium started in the application of modern technology , production growing . China began in the 1960s to extract smoke from roasting molybdenum rhenium and industrial production , so far, has become a rhenium production and application of one big country .

  Rhenium mineral rarely, and only Hui rhenium ore (ReS2) and rhenium sulfide copper ore (CuReS4). Rhenium mainly molybdenum, copper, lead, zinc , platinum, niobium minerals associated with the economic value of rhenium-containing minerals molybdenite, generally contain from 0.001% to 0.031% rhenium . But elected molybdenum porphyry copper containing up to 0.16% rhenium . The main raw material for the production of rhenium molybdenum by-product of the smelting process . Some copper , platinum ore, niobium ore sphalerite and even soot and slag smelting and processing of low-grade waste molybdenum , rhenium can be recovered .

  Rhenium content in the crust was 0.001 × 10-4%, reserves on the planet one of few non-ferrous metals . The world's proven reserves of about 2500t, resources 10000t, mostly in Chile, the former Soviet Union , Canada and other regions , China's reserves of rhenium is 237t. Less production of rhenium , rhenium in recent years, the global annual production of only 30-50t, and high-tech materials with rhenium consumption level of technology 's rapid development, has steadily increased .

  The nature of rhenium

  The physical properties of rhenium

  Rhenium is a very hard, silvery-white metal that looks like platinum the same, but pure rhenium powder , color is generally gray . The physical properties of rhenium and family of the periodic table of the first refractory metal Ⅶ molybdenum and tungsten are very similar physical properties , in addition to the platinum group metals , especially platinum , ruthenium, osmium is somewhat similar . Rhenium is a refractory metal , rhenium melting point 3180 ℃, second tungsten, and molybdenum, tungsten , are very refractory metal . A significant proportion of rhenium , the relative density of 21.03g/cm3, only platinum, iridium, osmium than the proportion of high rhenium , rhenium as this feature makes the most dense metal other than platinum group metals , and has a very large hardness , wear resistance, corrosion-resistant properties . Rhenium has high mechanical strength , which is thinner than a human hair a rhenium alloy wire , able to withstand gravity above 7 kg . In addition, there is a high resistance of rhenium and other electrical properties , the resistivity of tungsten rhenium 3.84 times that of its modulus of elasticity and mechanical properties and iron almost. Natural rhenium by the composition of two isotopes Re187 and Re185 , Re187 of radioisotopes in the natural rhenium accounted for 62.6%; Re185 non- radioactive isotope , accounting for 37.2%. Re187 half-life of 43 million a, emit radiation is very weak, can not wear through the skin, the human body without harm.

  Chemical properties of rhenium

  Rhenium chemical stability, corrosion resistance, is not oxidized in the air , acids and bases its corrosive effect is small. Rhenium stable at room temperature , 300 ℃ begins to be oxidized . With sulfur vapor at high temperature synthesis rhenium disulfide , with fluorine , chlorine , bromine to form halides. Rhenium is not dissolved in hydrochloric acid , soluble in hot concentrated nitric acid and sulfuric acid to generate perrhenate (HReO4). Rhenium strong oxophilic , the oxidation state of +1 , +2, +3 , +4, +5 , +6, +7, and oxides Re2O, Re2O3, ReO2, ReO3, Re2O7. High rhenium oxide (Re2O7) soluble in water , usually processed into stable salts , such as ammonium perrhenate (NH4ReO4) , and rhenium potassium (KReO4). Rhenium does not react with the carbon , is the only non- refractory metal carbide and carbon generated elements. Chemical properties of rhenium are the most prominent and its seven highly volatile oxide , and it is easily dissolved in water and oxygenated solvents. Widely used in the recovery of rhenium in these two properties . The acidic aqueous solution of rhenium , electromotive force between the copper and thallium , therefore , rhenium, iron and zinc can be precipitated in an aqueous solution .

  The main purpose of rhenium
  Uses
  Since all these rhenium having excellent properties , so it has become important in many areas of materials used . In the metallurgical industry , rhenium as an alloying elements are added to improve the alloy can improve performance . For example , pure tungsten and pure Mo in the case of low temperature may become brittle as glass, difficult processing technology , which use is restricted . However, adding an appropriate amount of tungsten or molybdenum rhenium tungsten- rhenium alloy or made ​​of molybdenum rhenium alloy , then with good ductility , can be processed into a variety of structural materials, but also to maintain a high hardness, high strength , and temperature and other characteristics . U.S. manned spacecraft is on a lot of parts manufactured using such rhenium alloy . Chrome-nickel alloy is added in a small amount of rhenium, can greatly improve the alloy melting point and strength , with this alloy parts , its life may be extended several times to several times .

  Rhenium is mainly used as a catalyst for the oil industry , and high-temperature alloys and superalloys elements additives, pure rhenium products can be used for particularly harsh atmosphere of high temperature components. Plated metal rhenium ( such as for space technology plated tungsten rhenium ) increase the wear resistance and corrosion resistance. Rhenium wire or plated with rhenium and tungsten filament as a cathode tube , containing a small amount of water in argon or nitrogen is more durable than the tungsten . Rhenium has a high temperature stability and strength under the action of the arc anti-corrosion capability , so rhenium -tungsten alloy electrical contact points for the working part , with the performance of platinum, ruthenium , compared products .
  Rhenium has a high electron emission properties, widely used in radio , television and vacuum technology . Rhenium has a very high melting point, is a major high-temperature instrumentation materials , tungsten rhenium thermocouples at 3100 ℃ is not softened. Tungsten or molybdenum, rhenium is added to form alloys increases ductility . Rhenium and rhenium alloys can be made tube components and ultra high temperature heater to evaporate metals. Rhenium in rockets, missiles for high temperature coating , use of instruments and spacecraft components such as high-temperature heat shield , arc discharge , electrical contacts and so need rhenium .

  Rhenium effect - rhenium alloy
  A substantial increase in the addition of rhenium tungsten, molybdenum , chromium, strength and ductility , it is the phenomenon called " rhenium effect ." Add a small amount ( 3% to 5 %) of the rhenium to the tungsten recrystallization starting temperature 300 ℃ ~ 500 ℃. Tungsten- rhenium and molybdenum rhenium alloy has good high temperature strength and ductility, can be processed into plates, sheets, wire, wire, rod, used for high-temperature aerospace structural parts ( nozzle , nozzle, heat shield , etc. ) , the elastic element , electronic components, etc. , but also for the manufacture of heating elements , artifacts, bulb , X-ray equipment , and medical instruments. W-Re-ThO2 alloys can be used as high-temperature heating parts, tungsten rhenium, molybdenum, rhenium alloy contact corrosion and high temperature with high thermal conductivity and can improve power supply reliability and working life of the equipment . Such as: platinum rhenium alloy ; platinum- tungsten- rhenium alloy ; tungsten- rhenium alloy ; molybdenum rhenium alloys.

  Rhenium expensive, in the application use more rhenium -containing alloy wherein tungsten rhenium and molybdenum rhenium alloy most widely used . Tungsten- rhenium alloy containing 1% to 26% rhenium , molybdenum, rhenium alloys containing rhenium content of 11% to 50%. There is also W-33.3Mo-33.3Re, Mo-Re-Hf-Zr, Mo-Re-Hf-V alloys , tungsten and nickel base superalloys radical pluralism rhenium , etc., after several alloys with high strength and high temperature performance, used in aerospace equipment, key parts .

  Catalyst
  Rhenium whose electronic structure 4d layer unsaturated five electronic easy release , and 6s layer 2 in the action of electron and easy to form a covalent bond , with its larger lattice parameter properties, so rhenium and compound has an excellent catalytic activity of the catalyst for the petrochemical industry the major uses of their traditional . Pt-Re/Al2O3 as reforming catalysts for petroleum , but cheap as other alternatives such as platinum - Tin Catalyst appearance , although its performance is slightly inferior , but the application of rhenium in this field is still decreased. In addition , rhenium used for production of unleaded gasoline and automobile exhaust purification catalyst ; rhenium sulfide such as cresol and lignin hydrogenation catalyst ; NH4ReO4 / C for cyclohexane dehydrogenation and ethanol dehydrogenation catalyst ; KReO4 , / SiO2 is also a series of hydrogenation catalyst ; Re2O7 is to make the conversion of SO2 to SO3, and transformed into HNO3 HNO2 make a good catalyst .

  Defense, aerospace industry
  Rhenium is one of the most refractory metal , its melting point up to 3180 ℃,, second only to tungsten 3410 ℃. By the rhenium and other metals can be obtained a series of high temperature resistance, corrosion resistance, wear-resistant alloys, such as Re25-W was a space station nuclear reactor materials , was developed to better performance Re30-W-Mo30 alloy ; Re-Pt with for the nuclear reactor structural material, resistant to heat at 1000 ℃ download the corrosion , radiation shields can also be used ; Re-Mo alloy to 3000 ℃ still has high mechanical strength , can be used to manufacture of supersonic aircraft and missiles high temperature strength member and as a heat shield . Particularly for jet engine turbine blades and turbine thermal power machine , nickel-based material containing rhenium successful development of superalloys ( 3% -7 % rhenium , melting point of 3180 ℃ above ) and applied to aircraft and aircraft , fire generators, the United States , Western Europe, greatly increased the amount of rhenium , rhenium consumption also makes the world's rapid growth . In recent years, the amount of rhenium in the alloy in the catalyst has exceeded the amount of area , superalloys become its most important applications.

  Temperature , heating components and high temperature measurement
  Re3-W and Re25-W alloy wire produced by thermocouples, temperature and thermal emf good linear relationship between temperature measurement accuracy , wide measurement range (0-2485 ℃). Its thermal electromotive force of 1012mV, than Pt-Rh/Pt ( at 1900 ℃ with only 30mV) is high , used in vacuum or inert gas medium temperature to be 2700 ℃, and the price is cheaper than Pt-Rh/Pt thermocouple . Re28-W / W thermocouple temperature to 2760 ℃, Mo-Re thermocouple temperature to 3000 ℃.
  A rhenium -based alloy produced by the heating element of tungsten or molybdenum compared to 5-10 times longer life ; temperatures Re8-12-Ni-Cr Ni-Cr alloy compared to the heating element 9 times higher than the working life , and has a high temperature and working under the pressure of the outstanding advantages ; Tim rhenium Rh-Ir over Rh-Ir only increase strength, but also improve the mechanical properties, used in aerospace and missile . Rhenium -based alloys can be produced at high temperatures without deformation of the spring both sensitive for temperature measuring instruments are necessary . Rhenium as photosensitive dyes absorb solar energy solar cells has broad application prospects.

  Electronics Industry
  Rhenium and tungsten, molybdenum, or platinum group metal or alloy composed of coating material , because of its high melting point, resistance, magnetic intensity and stability of the environment and widely used in the electronics industry. 3% -20% Re -doped tungsten or H4ReO4 coated tungsten wire, neither as brittle as tungsten , but also improve the elongation and resistance , with high shock and vibration performance , so in vacuum technology and Easy vibration place in an electronic device or filament showing its important uses , such as X-ray target , flash , acoustic spectrometer , the measured voltage high vacuum parts , aircraft tungsten rhenium wire lamp , TV rapid starting heaters. Re-Pt, Re-Ag, Re-Cu, Re-Cu-Zr platinum , have been substituted for the electrical switch, key , an arc current cut-off device and the contact elements or discharge shielding member , with the advantage of reliable and durable . Molybdenum Rhenium cermet anodes practical application . In recent years, one kinds of rhenium -based composite material as a base material for ultra high emitter , the thermal electron discharge effect increased by 20 % and the current density increases , thermal discharge performance improves .

  Coating and welding materials
  The use of high-melting rhenium and corrosion resistance characteristics as Premium coating , such as rhenium metal coated wire, sheet , or tube , to achieve the anti- acid, alkali , water or sulfur compounds object of etching , it is used marine and chemical industries ; Re-NiRe-Mo or R-W as instrument components , rocket warheads and their engines coating.
  Will be added to the W or Mo Re alloys , both to increase its strength, but also to improve its plasticity and weldability , can be used for welding electrodes W or Mo devices used .

  Other Uses
  Medical radioactive rhenium - amino acid compounds to treat cancer , KReO4 preparation of color photographic film can be used as a sensitizing agent.

  Rhenium market conditions
  Rhenium market demand and high-tech industries are closely related. As a strategic material , rhenium major consuming countries are the United States, Western Europe, Japan and other developed countries and the Russian military power . In recent years, the world's total annual consumption reached 40t, and has been increasing year by year . Which the European economic situation is good, consumption increases rapidly, and its annual consumption by the 2-3t to nearly 10t. U.S. annual consumption for rhenium maintained at 20-25t. Japan rhenium consumption is also with the economic recovery growth of about 2-3t / a scale , mainly for electronic materials such as car exhaust sensor Re-W wire, thin film integrated circuit electrodes. Russia's annual demand of about rhenium 5t.
  Chile is the world's largest supplier of rhenium , which occupy more than 60% of U.S. imports of rhenium raw materials market ; production of rhenium other countries the United States, Russia, Germany , Kazakhstan, China and so on.
Due to the recent resource utilization technology is rapidly increasing, from waste recycling rhenium catalyst volume showed a steady growth, while the native rhenium production is also increasing year after year , so although the yearly world consumption of rhenium , rhenium , but prices are still relatively stable.

  Atomic no. 75
  Relative atomic mass 186.207
  Melting point 3180 ° C
  Boiling point 5627 ° C
  Density 21020 kgm-3
  Electrical resistivity 19.3 x 10-8 Ohms m
  Young's modulus 466 Gpa
  Heat capacity 25.48 J / K / mol
  Abundance 4 x 10-4 ppm
  Thermal conductivity 47.9 W / m / K

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