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Rhenium is a chemical element with the symbol Re and atomic number 75. It is a silvery-gray, heavy, third-row transition metal in group 7 of the periodic table. With an estimated average concentration of 1 part per billion (ppb), rhenium is one of the rarest elements in the Earth's crust. Rhenium has the third-highest melting point and second-highest boiling point of any element at 5869 K. Rhenium resembles manganese and technetium chemically and is mainly obtained as a by-product of the extraction and refinement of molybdenum and copper ores. Rhenium shows in its compounds a wide variety of oxidation states ranging from −1 to +7.
Tungsten, or wolfram, is a chemical element with the symbol W and atomic number 74. Tungsten is a rare metal found naturally on Earth almost exclusively as compounds with other elements. It was identified as a new element in 1781 and first isolated as a metal in 1783. Its important ores include scheelite and wolframite, the latter lending the element its alternate name.
Group 6, numbered by IUPAC style, is a group of elements in the periodic table. Its members are chromium (Cr), molybdenum (Mo), tungsten (W), and seaborgium (Sg). These are all transition metals and chromium, molybdenum and tungsten are refractory metals.
Wolframite is an iron, manganese, and tungstate mineral with a chemical formula of (Fe,Mn)WO4 that is the intermediate mineral between ferberite (Fe2+ rich) and hübnerite (Mn2+ rich). Along with scheelite, the wolframite series are the most important tungsten ore minerals. Wolframite is found in quartz veins and pegmatites associated with granitic intrusives. Associated minerals include cassiterite, scheelite, bismuth, quartz, pyrite, galena, sphalerite, and arsenopyrite.
Refractory metals are a class of metals that are extraordinarily resistant to heat and wear. The expression is mostly used in the context of materials science, metallurgy and engineering. The definition of which elements belong to this group differs. The most common definition includes five elements: two of the fifth period and three of the sixth period. They all share some properties, including a melting point above 2000 °C and high hardness at room temperature. They are chemically inert and have a relatively high density. Their high melting points make powder metallurgy the method of choice for fabricating components from these metals. Some of their applications include tools to work metals at high temperatures, wire filaments, casting molds, and chemical reaction vessels in corrosive environments. Partly due to the high melting point, refractory metals are stable against creep deformation to very high temperatures.
The Outpost Island Mine was a gold and tungsten producer 94 kilometres southeast of Yellowknife, Northwest Territories on an island of Great Slave Lake. Gold was discovered here in 1935 by prospectors, and some development was undertaken in 1936–1938. Tungsten ores became valuable during World War II, so the owners investigated the tungsten possibilities of the mine. It produced small amounts of gold, copper, and tungsten during 1941–1942, and then again in 1951-1952 during the Korean War. It was a small deposit and was not considered economic because of unpredictable tungsten market prices in the 1950s.
In chemistry, a tungstate is a compound that contains an oxyanion of tungsten or is a mixed oxide containing tungsten. The simplest tungstate ion is WO2−4, "orthotungstate". Many other tungstates belong to a large group of polyatomic ions that are termed polyoxometalates, ("POMs"), and specifically termed isopolyoxometalates as they contain, along with oxygen and maybe hydrogen, only one other element. Almost all useful tungsten ores are tungstates.
Greisen is a highly altered granitic rock or pegmatite, usually composed predominantly of quartz and micas. Greisen is formed by self-generated alteration of a granite and is a class of moderate- to high-temperature magmatic-hydrothermal alteration related to the late-stage release of volatiles dissolved in a magma during the solidification of that magma.
Sodium tungstate is the inorganic compound with the formula Na2WO4. This white, water-soluble solid is the sodium salt of tungstic acid. It is useful as a source of tungsten for chemical synthesis. It is an intermediate in the conversion of tungsten ores to the metal.
Orion Electronics Ltd is a consumer electronics company headquartered in Budapest, Hungary. Orion supplies a wide range of brown and white goods including televisions, DVD players/recorders/with HDD, home theatre systems, Navigation Systems, Portable DVD Players, active speaker systems, computer monitors, MP3/MP4 players, washing machines, dishwashers, cooking ranges, microwave ovens and the full range of small domestic appliances. The company is owned and managed by the Thakral Corporation of Singapore.
Ammonium paratungstate (or APT) is a white crystalline salt with the chemical formula (NH4)10(H2W12O42)·4H2O. It is described as "the most important raw material for all other tungsten products."
Mawachi a region in the Bawlake district of the Kayah State of Myanmar.
Burundi is a producer of columbium (niobium) and tantalum ore, tin ore, and tungsten ore, and some deposits of gold which are designated for export. Burundi has resources of copper, cobalt, nickel, feldspar, phosphate rock, quartzite, and rare reserves of uranium, and vanadium. The country is also a producer of limestone, peat, sand and gravel for domestic consumption and as building materials. As of 2005, manufacturing accounted for 8% of the country's gross domestic product.
Drakelands Mine, also known as Hemerdon Mine or Hemerdon Ball Mine, is a tungsten and tin mine. It is located 11 km northeast of Plymouth, near Plympton, in Devon, England. It lies to the north of the villages of Sparkwell and Hemerdon, and adjacent to the large china clay pits near Lee Moor. The mine had been out of operation since 1944, except for the brief operation of a trial mine in the 1980s. Work started to re-open it in 2014, but it ceased activities in 2018. It hosts the fourth largest tin-tungsten deposit in the world.
The Myszków mine is a large mine in the centre of Poland in Myszków, Myszków County, 258 km south-west of the capital, Warsaw. Myszków represents one of the largest copper and silver reserve in Poland having estimated reserves of 1,334 million tonnes of ore grading 0.15% copper and 2.37 g/tonnes silver. The 1.334 billion tonnes of ore contains 2 million tonnes of copper metal and around 3,200 tonnes of silver but the deposit also grades 0.07% molybdenum that contains 934,000 tonnes of molybdenum metal and 0.05% tungsten that contains 667,000 tonnes of tungsten metal.
Rewat is a small village near Degana, Nagaur district, Rajasthan in northern India, having 500-600 houses.
Mining in Rwanda consists of extracting such minerals as tin, tantalum, and tungsten. In 2020, Rwanda earned about US$733m from mineral exports, making mining the biggest source of export revenues after tourism.
Needle Hill or Cham Shan is a mountain in New Territories, Hong Kong. It has an altitude of 532 m. This is a part of a popular hiking route including Grassy Hill and Tai Mo Shan. The mountain got its name due to the resemblance of a needle by its peak.
Zakamensk is a city of a regional significance in Russia, administration center of Zakamensky District of the Republic of Buryatia. Since 2015 the city has an honorary international title "The city of Labor Valor and Glory"
Toulon is a former non-agency railroad station in Pershing County, Nevada, United States.
References
- ↑ Pohl, Walter L. (2011). Economic Geology: Principles and Practice. John Wiley and Sons. pp. 179–183. ISBN 978-1-4443-3662-7.
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