Tungsten has a very high melting point, the highest of all alloy metals, do you really know?
Tungsten is a chemical element, the chemical symbol is W, the atomic number is 74, is a very hard, steel gray to white transition metal. The minerals containing tungsten are wolframite and scheelite.The physical characteristics of tungsten are very strong, especially the melting point is very high, which is the highest of all non-alloy metals. Pure tungsten is mainly used in electrical and electronic equipment, and many of its compounds and alloys are also used in many other applications (the most common filament with light bulbs, tungsten in X-ray tubes and superalloys). Tungsten is a rare and high melting point metal, which belongs to the sixth cycle (the second long period) of the periodic table. Steel tungsten is not only a non-ferrous metal, but also an important strategic metal. Tungsten ore was called "heavy stone" in ancient times. Scheelite was discovered by Swedish chemist Carl William Sheyer in 1781, and a new elemental acid-tungstate was extracted, and tungstate was also extracted from wolframite discovered by Spanish de Puer in 1783. In the same year, tungsten powder was obtained by reducing tungsten trioxide with carbon for the first time and named this element. The content of tungsten in the crust is 0.001%. Twenty kinds of tungsten-bearing minerals have been found. Tungsten deposits are generally formed with the activity of granitic magma.
The smelted tungsten is a silver-white metal with high melting point and high hardness. The tungsten-containing minerals include wolframite and scheelite. The physical characteristics of tungsten are very strong, especially the melting point is very high, and is the highest among all non-alloy metals. Pure tungsten is mainly used in electrical and electronic equipment, and many of its compounds and alloys are also used in many other applications (the most common filament with the bulb, in the X-ray tube and also in high-temperature alloys). The most recently established three-radioactive isotope of the most recent baboons have the same micro-activity. Isotopes: There are five isotopes of tungsten present in nature, and their half-life is very long, so it can be seen as a stable isotope. All of these isotopes can be deciduized by decay. The half-life that can be measured up to now is 180 W, with a half-life of 1.8 to 1018 years, and other isotopes are not observed for natural decay, and the half-life of forced degradation:182 W, T 1/2> 8.3 years,184 W, T 1/2> 29 years,185 W, T 1/2> 13 years,186 W, T 1/2> 27 years. So far their half-life is only a theoretical value. The average annual decay occurs twice a year in one gram of 180 W. At present, there are 27 artificial radioisotopes, the most stable is 181W, the half-life is 121.2 days, the half-life of 185W is 75.1 days, the half-life of 188W is 69.4 days, and the half-life of 178W is 21.6 days. The half-life of the other radioisotopes is below 24 hours, most of which are less than 8 minutes.
Development history: tungsten is not only a non-ferrous metal, but also an important strategic metal. Tungsten ore is called "heavy stone" in ancient times. Scheelite was discovered by Swedish chemist Carl William Scheler in 1781 and a new elemental acid-tungstate was extracted. Tungstate was also extracted from wolframite discovered by Spanish de Puer in 1783. In the same year, tungsten powder was obtained for the first time by reducing tungsten trioxide with carbon, and the element was named. The content of tungsten in the crust is 0.001%. There are 20 kinds of tungsten minerals found. Tungsten deposits are generally formed with the activity of granitic magma. After smelting, tungsten is a silver-white glossy metal with a very high melting point and high hardness. Tungsten is the metal with the highest melting point. In the 1850s, chemists discovered the effect of tungsten on the properties of steel. However, tungsten steel began to be produced and widely used at the end of the 19th century and the beginning of the 20th century. High-speed steel was on display for the first time at the Paris World Expo in 1900. Therefore, the tungsten extraction industry has been developed rapidly since then. The emergence of this kind of steel marks a major technological progress in the field of metal cutting. Tungsten is the most important alloy element. In 1900, the Russian inventor first recommended the use of tungsten in lighting bulbs.
In 1909, the method of powder metallurgy based on powder metallurgy is developed, and after the process of pressure processing, tungsten can be widely used in electric vacuum technology. In 1927 _ 1928, a hard alloy was developed by using tungsten carbide as the main component. This is an important stage in the development of tungsten industry. The properties of each of these alloys exceed the best tool steel and are widely used in modern technology. Source: wolframite, scheelite, tungsten iron ore and other minerals contain tungsten. The important tungsten ore is in Bolivia, the United States of California and Colorado, China, Portugal, Russia and South Korea. China produces 75% of the worldundefineds tungsten. Pure metal is obtained by using an oxide of carbon-reducing tungsten. The total amount of tungsten in the world is estimated to be 7 million tons, of which about 30 per cent are wolframite and 70 per cent are scheelite. However, most of these deposits are not currently economically mined. It is only about 140 years for these deposits to be used in accordance with the current consumption. Another method of obtaining tungsten is to recover. The recovered tungsten is high in content and in fact very profitable. Chemical property: tungsten is a rare high-melting point metal, which can improve the high-temperature hardness of the steel and belongs to the group VI B of the sixth cycle (second long period) in the periodic table of the element.
W is a silver-white metal with a steel-like appearance. The melting point of the tungsten is high, the vapor pressure is low, and the evaporation speed is also small. the chemical property of the tungsten is stable and does not react with air and water at normal temperature; when the tungsten is not heated, any concentration of hydrochloric acid, sulfuric acid, nitric acid, hydrofluoric acid and aqua regia do not work for tungsten, The other acids have a weak effect on the tungsten. At normal temperature, tungsten can be rapidly dissolved in a mixed acid of hydrofluoric acid and concentrated nitric acid, but does not work in a base solution. In the presence of air, the molten base can oxidize the tungsten to a tungstate, and in the presence of an oxidizing agent (NaNO3, NaNO2, KClO3, PbO2), the reaction of the generation of the tungstate is more violent. Can be combined with chlorine, bromine, iodine, carbon, nitrogen, sulfur, and the like at a high temperature, but is not combined with the hydrogenation. Associated ore: There are more than ten tungsten ores in China. There are mainly two types of wolframite (wolframite) and scheelite (calcium tungstate). Wolframite (feMn) WO4. The color is dark gray, light red, brown, brown, brown and brown. Semi-metallic luster, metallic luster and resin gloss. It is usually in the form of a blade, a curved sheet, a granular and a compact form, and also has a monoclinic crystal of a thick plate, a sharp column and the like, and is usually filled with white quartz in the form of a vein, in the form of a vein, in the rock fracture near the granite and its vicinity. The hardness is 5-5.5 and the specific gravity is 7.1-7.5. Stagger fracture. It is brittle and has weak magnetism. The wolframite is the main raw material for smelting tungsten and producing tungstate.
