The source of tungsten
The minerals such as wolframite, scheelite, and tungsten iron ore 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. 2. scheelite MnWO4. The color is off-white, and also has yellow brown, green and light red, etc. The gloss of the grease. It belongs to the tetragonal system, and forms a double-cone-shaped pseudo-octahedral or plate-like crystal, and the crystal faces are sometimes visible with oblique stripes, in which the interposers are more common. The crystals also have a shell-like, kidney-like, granular and compact block. The hardness is 4.5 to 5, and the specific gravity is 5.9 to 6.2. Brittle, shell-like, or differential-like fracture. When illuminated by a fluorescent lamp, the scheelite can emit beautiful light blue fluorescence. The white-tungsten ore is produced in the fields of Dag, Hunan, Yunnan Wenshan, etc. And the ore is obtained by elutriation and washing to obtain the scheelite ore. [1] The distribution of resources: the abundance of tungsten in the earthundefineds crust is 1.2X10-4%. 24 kinds of tungsten minerals have been found. Among them, there are two kinds of wolframite and scheelite with industrial value, and the worldundefineds resources are mainly concentrated in the ring-Pacific belt and Eurasia-North American continent. The worldundefineds tungsten reserves are 281.69 million tons, mainly in China, Canada, North Korea, Russia, the United States, Australia and other countries. China is located in the above-mentioned two tungsten ore areas. The ore quality is good. The ore has a complete variety of ore. The reserves are the first in the world, up to 232 million tons, the main production of Jiangxi, Hunan, Fujian, Guangdong, Yunnan, Guangxi and other provinces. China is a big-producing country with a tungsten resource of 5.2 million tons, which is more than 3 times the total reserves of 30 tungsten-producing countries in the world (1.3 million tons), and the output and export volume are the first in the world. The reserves of tungsten in the three provinces of Hunan, Jiangxi and Henan are the first three in the whole country. The reserves of tungsten in the two provinces of Hunan and Jiangxi account for 55.48% of the whole country. Hunan takes white tungsten as the main, and Jiangxi is dominated by black tungsten, and its black tungsten resources account for 42.40% of the total amount of black tungsten resources in the whole country. Chinaundefineds tungsten ore is generally distributed along the eastern coast of Guangdong, on both sides of the Nanling Mountain of China, especially in the south of Jiangxi, with the reserves of about one-half of the world. In addition, the province of Jiangxi, the city of Ruicheng, Zixing, the Mausoleum, etc., and the provinces such as Guangxi and Yunnan also have the tungsten ore. In addition to China, there are countries with tungsten resources in the world, including Canada, Austria, Russia, Australia and Vietnam.
