Molecular Formula | Re |
Molar Mass | 186.21 |
Density | 21.02 g/cm3 (lit.) |
Melting Point | 3180 °C (lit.) |
Boling Point | 5596 °C (lit.)5627 °C (lit.) |
Water Solubility | Insoluble in water. |
Appearance | wire |
Specific Gravity | 21.04 |
Color | Silver-gray |
Exposure Limit | ACGIH: TWA 1 mg/m3OSHA: TWA 15 mg/m3; TWA 5 mg/m3 |
Merck | 13,8261 |
Storage Condition | Flammables area |
MDL | MFCD00011195 |
Physical and Chemical Properties | Powder rhenium is stable in room temperature air, easy to burn when heated, and will be strongly oxidized to Re2O7 at a temperature higher than 873K. The bulk rhenium is also stable at room temperature and is oxidized to form volatile Re2O7 when heated to a temperature of 1273K. Rhenium and hydrogen, nitrogen, carbon does not react, but the powder can absorb hydrogen. Rhenium reacts with sulfur vapor to form ReS2, and its reaction rate accelerates with the increase of temperature. In an oxygen-free atmosphere, the heated rhenium can react with fluorine, chlorine and bromine to form the corresponding halides ReF6, ReF7, ReCl3, ReCl5 and rebr3. The characteristics of rhenium are similar to those of the same subgroup elements, in particular to manganese. The valence of rhenium can vary from 1 to 7, and the common valence states are 7 and 4. Therefore, rhenium and its compounds have excellent catalytic activity. Rhenium is not soluble in water, hydrochloric acid, hydrofluoric acid or dilute sulfuric acid, but soluble in nitric acid, hot concentrated sulfuric acid or hydrogen peroxide, the formation of high rhenium acid. Rhenium is fused with a mixture of sodium peroxide or potassium hydroxide and potassium nitrate to form a perrhenium salt. Rhenium oxides, especially Re2O7, soluble in water and alcohol, the aqueous solution is acidic reaction, the electromotive force is 0.6V, between copper and thallium. Therefore, rhenium, like copper, is easily replaced by metallic iron from its salt solution. At high temperature and high pressure, the hydrazine powder reacts with carbon monoxide to form the carbonyl compound Re2(CO)10. |
Use | Used as a spectral purity reagent |
Risk Codes | R34 - Causes burns R11 - Highly Flammable R36/38 - Irritating to eyes and skin. |
Safety Description | S16 - Keep away from sources of ignition. S45 - In case of accident or if you feel unwell, seek medical advice immediately (show the label whenever possible.) S36/37/39 - Wear suitable protective clothing, gloves and eye/face protection. S26 - In case of contact with eyes, rinse immediately with plenty of water and seek medical advice. S33 - Take precautionary measures against static discharges. S27 - Take off immediately all contaminated clothing. |
UN IDs | UN 3178 4.1/PG 2 |
WGK Germany | 3 |
RTECS | VI0780000 |
TSCA | Yes |
Hazard Class | 8 |
Packing Group | III |
EPA chemical substance information | information provided by: ofmpeb.epa.gov (external link) |
metal rhenium | symbol Re, atomic number 75, atomic weight 186.31, belonging to Group VII A of the periodic table of elements, gray-white, is a kind of refractory metal material, is a typical scattered metal, does not form their own independent minerals in nature, but in the form of sulfide as an impurity component in the distribution of molybdenite, chalcopyrite and other minerals, the content of about 10-7% in the crust. Metal rhenium powder is shown in Figure 1. |
History of discovery | as early as 1872, Russian scientist Mitri mendelev predicted the periodic law of elements, there is an element of "sub-manganese" with an atomic weight of 190 which has not been found in nature. Until 1925, Nodak, Germany (W.Noddack) and terck (I.Tacke) couple and Berg (O.Berg) separation of the Norwegian-produced niobite to obtain rhenium heptaoxide Re2O7, and the rhenium element was found by X-ray spectrum analysis of the platinum concentrate, and the new element was named rhenium in memory of the Rhein. Later, Nodak found that rhenium mainly exists in molybdenite, and the metal rhenium was extracted from it. The content of rhenium in the ore is low and the price is expensive. After 1950, the metal rhenium from the laboratory into an important treasure of the emerging metal materials, in the modern technology began to apply, the production of increasing development. China began in 1959 from molybdenum concentrate roasting flue gas leaching and dust extraction of rhenium, is now able to produce the domestic needs of a variety of rhenium products. |
physical properties | the type of rhenium elemental lattice is hexagonal-dense, melting point 3440 ℃, belonging to high melting point metal; rhenium's melting point second only to carbon and tungsten, density, boiling point in all the first element, resistivity than tungsten 3 times. Rhenium hardness, high mechanical strength, has good plasticity, easy to draw wire rolling at room temperature, but can not withstand hot processing. The density is almost 2 times that of lead; The appearance is the same as platinum, silver gray; Pure rhenium is soft and has good mechanical properties. FIG. 2 shows the main physical properties of rhenium. |
rhenium compounds | There are many rhenium compounds, which are divided into inorganic rhenium compounds, rhenium metal cluster compounds and organic rhenium compounds. Inorganic rhenium compounds include oxides, perrhenium acids and salts thereof, sulfides, halides, and carbon-based compounds. There are 8 kinds of oxides such as ReO4, ReO7, ReO3, Re2O5, ReO2, Re2O3, ReO and Re2O, among which Re2O7, ReO3 and ReO2 are more stable. The perrhenate HReO4 and its main salts are potassium perrhenate, sodium perrhenate, calcium perrhenate and ammonium perrhenate. The rhenium sulfides are Re2S7, ReS3, ReS2, Re2S3 and ReS, of which only Re2S7 and ReS2 are more stable. The main inorganic rhenium compounds which have a great relationship with the extraction metallurgy are shown in figure 3. rhenium can form polynuclear complexes containing metal-metal bonds. Such as binuclear metal cluster compound [Cl4-Re-Re-Cl4]2-and trinuclear metal cluster compound [Re3Cl9]3-. The organic compounds of rhenium related to the extraction metallurgy are listed in Table 3. FIG. 3 is a main inorganic rhenium compound. |
application field | 1. Compounds of rhenium (mainly ammonium gallate and potassium rhenium) it is mainly used in the petroleum and chemical industry to replace platinum catalyst, reduce the working pressure and temperature of the production process, improve the process parameters, and prolong the catalyst life (increase by 2~3 times). Rhenium is used for tungsten, molybdenum alloys or other alloy additives. For example, tungsten-rhenium alloys are used as high-temperature structural materials in aerospace technology in the form of rods, plates, tubes, sheets and wires, electron tubes, picture tubes and bulb wires, electrical contact materials, high-temperature thermocouple materials, etc, because of its performance over pure molybdenum and Other molybdenum alloys, can be used as fusion reactor structural materials. 2, rhenium is a kind of active catalyst, good selectivity, strong anti-toxic ability (by other substances contaminated still maintain its catalytic ability), widely used in petrochemical industry. 70% of the total rhenium demand worldwide is used to prepare platinum-rhenium reforming catalysts in the petrochemical industry. This catalyst is used for the production of lead-free high-octane gasoline and is superior to pure platinum catalysts. It is more stable, longer life cycle, can be used for the processing of low-quality oil, but also at low pressure operation. China began to use platinum-rhenium catalyst in petroleum refining in 1969, is still in the gradual development. Sulfides, chlorides and oxides of rhenium may also be used as catalysts. 3, the metal rhenium in the recrystallization after large plasticity, good ductility after annealing, in the high temperature heating process grain growth is very slow, in the oxidation atmosphere has good chemical stability, Some insulating materials do not react, and other metals have poor diffusion to rhenium, so rhenium is a good material for the manufacture of Electron Tubes. Rhenium and rhodium alloys (especially rhenium tungsten alloys) are used in electron tubes as heating filaments, anodes, cathodes, grids, tube seals, and structural materials. Compared with tungsten, molybdenum, good use effect, long life. It has been reported that the use of rhenium in place of tungsten in the cathode of an electron tube increases the service life by a factor of 100. 4. Rhenium is used as an additive for alloys in the metallurgical industry. For example, the addition of rhenium to Platinum can improve the wear resistance without reducing the corrosion resistance. This alloy is used in the manufacture of electrodes, filters for rayon industry, pen tips, and the like. Rhenium is added to the super heat resistant alloy of nickel to obtain a particularly strong heat resistant alloy, which can be used as a coating for military aircraft turbine blades, and its high temperature performance is the same as that of the whole alloy components, this results in a saving of the expensive rhenium. Rhenium containing tungsten, molybdenum, platinum and other thermocouples can be used for ultra high temperature measurement. Rhenium may also be used in the manufacture of rocket combustion chambers. |
rhenium raw material | The crust abundance of rhenium is 7 × 10-8%, and the proven world rhenium reserves in 1986 are 10300t, prospective reserves of 13170T. Up to now, only two independent rhenium minerals have been found, namely, phosphonium rhenium ore (ReS2) and copper rhenium sulfide mineral (CuReS4), which are associated with molybdenum, copper, lead, zinc, platinum, niobium and other minerals, especially associated with molybdenite and bornite. Therefore, the economic value of the extraction of rhenium raw materials mainly from molybdenum concentrate and copper concentrate. Generally, the rhenium grade of molybdenum concentrate does not exceed 1 × 10-2%, and the rhenium grade of by-produced molybdenum concentrate is usually high, generally (2~20) × 10-2%. The main raw material for the production of rhenium is the by-product of molybdenum and copper smelting processes. Smelting dust and slag of some uranium ore, platinum group metal ore, niobium ore and even sphalerite, as well as waste liquid and rhenium-containing waste materials for the treatment of low-grade molybdenum ore, such as platinum-rhenium catalysts and rhenium-containing waste alloys, also are the raw materials for the extraction of rhenium. Recovery of rhenium from rhenium-bearing ores is low. In the existing mines, the recovery rate of rhenium recovered to molybdenum concentrate is 20% ~ 50%, while the rhenium containing molybdenum concentrate is treated by common metallurgical methods, and the final rhenium product is recovered, and the average metallurgical recovery rate is about 60%. The availability of rhenium in the world is mainly concentrated in the Americas, followed by the former Soviet Union. China is also rich in rhenium reserves, accounting for about 1/10 of the world's reserves, mainly distributed in Jiangxi, Shaanxi and Hunan. The independent rhenium ore has not been found, and the currently used rhenium is mainly collected from the rhenium ore associated with the non-ferrous metal deposit with molybdenum and copper as the main body. The important types of associated deposits are magmatic copper sulfide nickel type, skarn type, high temperature hydrothermal quartz vein type, porphyritic type, layered type, vein type, copper-bearing sandstone type and so on. |
Recovery of rhenium | rhenium exists in nature in the form of ReS2 and ReCuS4, and is parasitized in molybdenite and copper-molybdenum concentrate, the highest content of up to 0.07%. The cost of ferromolybdenum can be reduced by recovering rhenium while roasting molybdenum ore. In the multi-layer baking furnace, 30-60% of rhenium is transferred to the gas phase, and the sublimation rate of rhenium in the fluidized bed furnace can reach 90%. In the roasting process, rhenium is oxidized to volatile and water-soluble Re2O7, which is absorbed by water, and then ammonium hydroxide or potassium rhenium is prepared by ion exchange method or extraction process. |
preparation of Rhodium powder | a metallurgical process for the production of metallic rhenium powder from pure rhenium compounds. The rhenium compounds commonly used in the production of fumarate powder include ammonium homoleate, potassium perrhenate, di-rhenium heptaoxide and rhenium pentachloride. The production methods include hydrogen reduction method, electrolysis method and halide thermal dissociation method. A method for reducing ammonium pervalerate with hydrogen in a hydrogen reduction method is commonly used in the industry. Hydrogen reduction method ammonium homoleate or potassium perrhenate is placed in a tubular reduction furnace for hydrogen reduction. The reduction is carried out as follows: KReO4 +3/2H2 = Re + KOH + 3H2O or NH4RO4 +3/2H2 = Re + NH3 + 4H2O. The reduction is usually performed in two fractions. The temperature of the first reduction of ammonium perchlorate is 573~623K, and the second reduction temperature is 1073~1223K. The first reduction temperature of potassium perrhenium is 773~823K, and the second reduction temperature is 1173~1273K. The purity of the fumed powder depends on the purity of the raw material. When the purity of high ammonium hydroxide is more than 99.99%, the purity of the obtained fumed powder can reach 99.99%, and the particle size can be less than 2.5 μm. Potassium perrhenate powder containing a large amount of potassium, that is, water, dilute hydrochloric acid after washing still contains a few thousand of potassium, purity of only 99%, this powder should not be used as a deep processing of raw materials. Therefore, the method of reducing potassium perrhenate raw material by hydrogen has been eliminated. Pure phosphonium powder can also be obtained by reduction of the rhenium heptaoxide raw material with hydrogen, but the cost is relatively high. Electrolytic process a process for preparing metallic phosphonium powder from an aqueous solution of ammonium perrhenate or potassium perrhenate by an aqueous solution electrolytic process. The electrolysis was carried out in an electrolytic cell with a platinum plate as an anode and a tantalum plate as a cathode. The mass concentration (g/L) of some components of the electrolyte is: ammonium homoleate 100, ammonium sulfate 60, sulfuric acid 100; Or potassium perrhenate 50, ammonium sulfate 40, sulfuric acid 75, with a current density of 1A/cm2 and an electrolysis temperature of 343K, the electrolyte was kept circulating and the concentration was kept stable, and the powder was periodically stripped from the cathode tantalum sheet. The resulting fumed powder was washed with alcohol and dried, and then treated with hydrogen gas at a temperature of 1073K. The particle size of the product powder is coarse, mostly more than 4 μm, which is not suitable for the production of dense rhenium by powder metallurgy. The electrolysis method using a rotating cathode (see suspension electrolysis) can obtain a finer powder. Electrolysis is generally used for rhenium plating on metal surfaces. Halide thermal dissociation method rhenium halide thermal dissociation (see iodide thermal dissociation method) can obtain metal rhenium. Using an inert gas as a carrier, the ReCl5 with a boiling point of 603K is brought into a heat-resistant glass chamber, reCl5 in the heat-resistant glass chamber encountered under vacuum heated to 1473~1573K of tungsten or Molybdenum wire thermal dissociation reaction occurs, the metal rhenium is deposited on the tungsten or Molybdenum wire. The gaseous product of the reaction may be returned for use. This method is mainly used for the plating of rhenium on tungsten and molybdenum products. |
Use | as a spectral purity reagent |