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White Tin
White tin is refined metallic tin. It contrasts with black tin, which is unrefined tin ore (cassiterite) as extracted from the ground. The term "white tin" was historically associated with tin mining in Devon and Cornwall where it was smelted from black tin in blowing houses. White tin may also refer specifically to β-tin, the metallic allotrope of the pure element, as opposed to the nonmetallic allotrope α-tin (also known as gray tin), which occurs at temperatures below , a transformation known as tin pest). White tin has tetragonal unit cell. References * * * * White White is the lightest color and is achromatic (having no chroma). It is the color of objects such as snow, chalk, and milk, and is the opposite of black. White objects fully (or almost fully) reflect and scatter all the visible wa ... Mining in Cornwall {{mining-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Refining (metallurgy)
In metallurgy, refining consists of purifying an impure metal. It is to be distinguished from other processes such as smelting and calcining in that those two involve a chemical change to the raw material, whereas in refining the final material is chemically identical to the raw material. Refining thus increases the purity of the raw material via processing. There are many processes including pyrometallurgical and hydrometallurgical techniques. Lead Cupellation One ancient process for extracting the silver from lead was cupellation. This process involved melting impure lead samples in a cupel, a small porous container designed for purification that would aid in the oxidation process, while being able to withstand the heat needed to melt these metals in a furnace. This reaction would oxidize the lead to litharge, along with any other impurities present, whereas the silver would not get oxidized. In the 18th century, the process was carried on using a kind of reverbe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Black Tin
Black tin is the raw ore of tin, usually cassiterite, as sold by a tin mine to a smelting company. After mining, the ore must be concentrated by several processes to reduce the amount of gangue it contains before it can be sold. It contrasts with white tin, which is the refined, metallic tin produced after smelting. The term "black tin" was historically associated with tin mining in Devon and Cornwall. References * * * * Black Black is a color that results from the absence or complete absorption of visible light. It is an achromatic color, without chroma, like white and grey. It is often used symbolically or figuratively to represent darkness.Eva Heller, ''P ... Mining in Cornwall {{Mining-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Cassiterite
Cassiterite is a tin oxide mineral, SnO2. It is generally opaque, but it is translucent in thin crystals. Its luster and multiple crystal faces produce a desirable gem. Cassiterite was the chief tin ore throughout ancient history and remains the most important source of tin today. Occurrence Most sources of cassiterite today are found in alluvial or placer deposits containing the weathering-resistant grains. The best sources of primary cassiterite are found in the tin mines of Bolivia, where it is found in crystallised hydrothermal veins. Rwanda has a nascent cassiterite mining industry. Fighting over cassiterite deposits (particularly in Walikale) is a major cause of the conflict waged in eastern parts of the Democratic Republic of the Congo. This has led to cassiterite being considered a conflict mineral. Cassiterite is a widespread minor constituent of igneous rocks. The Bolivian veins and the 4500 year old workings of Cornwall and Devon, England, are concentrate ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Tin Mining
Tin mining began early in the Bronze Age, as bronze is a copper-tin alloy. Tin is a relatively rare element in the Earth's crust, with approximately 2 ppm (parts per million), compared to iron with 50,000 ppm. History Tin extraction and use can be dated to the beginnings of the Bronze Age around 3000 BC, when it was observed that copper objects formed of polymetallic ores with different metal contents had different physical properties. The earliest bronze objects had tin or arsenic content of less than 2% and are therefore believed to be the result of unintentional alloying due to trace metal content in the copper ore It was soon discovered that the addition of tin or arsenic to copper increased its hardness and made casting much easier, which revolutionized metal working techniques and brought humanity from the Copper Age or Chalcolithic to the Bronze Age around 3000 BC. Early tin exploitation appears to have been centered on placer deposits of cassiterite. The first eviden ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Devon
Devon ( ; historically also known as Devonshire , ) is a ceremonial county in South West England. It is bordered by the Bristol Channel to the north, Somerset and Dorset to the east, the English Channel to the south, and Cornwall to the west. The city of Plymouth is the largest settlement, and the city of Exeter is the county town. The county has an area of and a population of 1,194,166. The largest settlements after Plymouth (264,695) are the city of Exeter (130,709) and the Seaside resort, seaside resorts of Torquay and Paignton, which have a combined population of 115,410. They all are located along the south coast, which is the most populous part of the county; Barnstaple (31,275) and Tiverton, Devon, Tiverton (22,291) are the largest towns in the north and centre respectively. For local government purposes Devon comprises a non-metropolitan county, with eight districts, and the Unitary authorities of England, unitary authority areas of Plymouth City Council, Plymouth an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Cornwall
Cornwall (; or ) is a Ceremonial counties of England, ceremonial county in South West England. It is also one of the Celtic nations and the homeland of the Cornish people. The county is bordered by the Atlantic Ocean to the north and west, Devon to the east, and the English Channel to the south. The largest urban area is the Redruth and Camborne conurbation. The county is predominantly rural, with an area of and population of 568,210. After the Redruth-Camborne conurbation, the largest settlements are Falmouth, Cornwall, Falmouth, Penzance, Newquay, St Austell, and Truro. For Local government in England, local government purposes most of Cornwall is a Unitary authorities of England, unitary authority area, with the Isles of Scilly governed by a Council of the Isles of Scilly, unique local authority. The Cornish nationalism, Cornish nationalist movement disputes the constitutional status of Cornwall and seeks greater autonomy within the United Kingdom. Cornwall is the weste ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Blowing House
A blowing house or blowing mill was a building used for smelting tin in Cornwall and on Dartmoor in Devon, in South West England. Blowing houses contained a furnace and a pair of bellows that were powered by an adjacent water wheel, and they were in use from the early 14th century until they were gradually replaced by reverberatory furnaces in the 18th century. The remains of over 40 blowing houses have been identified on Dartmoor. History The blowing house method of smelting tin was probably introduced early in the 14th century to replace the earliest method of smelting which had to be done in two stages – a first smelting probably took place near to the tinworks and the roughly smelted metal was taken to a stannary town to be smelted again to produce the final refined product. Each of these smeltings was taxed separately until 1303 when they were replaced by a single tax on the finished product. It is likely that this tax change was due to the improved smelting process prov ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Beta-tin
Tin is a chemical element; it has symbol Sn () and atomic number 50. A silvery-colored metal, tin is soft enough to be cut with little force, and a bar of tin can be bent by hand with little effort. When bent, a bar of tin makes a sound, the so-called "tin cry", as a result of twinning in tin crystals. Tin is a post-transition metal in Carbon group, group 14 of the periodic table of elements. It is obtained chiefly from the mineral cassiterite, which contains tin(IV) oxide, stannic oxide, . Tin shows a chemical similarity to both of its neighbors in group 14, germanium and lead, and has two main oxidation states, +2 and the slightly more stable +4. Tin is the 49th most abundance of the chemical elements, abundant element on Earth, making up 0.00022% of its crust, and with 10 stable isotopes, it has the largest number of stable isotopes in the periodic table, due to its magic number (physics), magic number of protons. It has two main allotropy, allotropes: at room temperature ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Allotrope
Allotropy or allotropism () is the property of some chemical elements to exist in two or more different forms, in the same physical state, known as allotropes of the elements. Allotropes are different structural modifications of an element: the atoms of the element are bonded together in different manners. For example, the allotropes of carbon include diamond (the carbon atoms are bonded together to form a cubic lattice of tetrahedra), graphite (the carbon atoms are bonded together in sheets of a hexagonal lattice), graphene (single sheets of graphite), and fullerenes (the carbon atoms are bonded together in spherical, tubular, or ellipsoidal formations). The term ''allotropy'' is used for elements only, not for compounds. The more general term, used for any compound, is polymorphism, although its use is usually restricted to solid materials such as crystals. Allotropy refers only to different forms of an element within the same physical phase (the state of matter, such as ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Alpha-tin
Tin is a chemical element; it has chemical symbol, symbol Sn () and atomic number 50. A silvery-colored metal, tin is soft enough to be cut with little force, and a bar of tin can be bent by hand with little effort. When bent, a bar of tin makes a sound, the so-called "tin cry", as a result of crystal twinning, twinning in tin crystals. Tin is a post-transition metal in Carbon group, group 14 of the periodic table of elements. It is obtained chiefly from the mineral cassiterite, which contains tin(IV) oxide, stannic oxide, . Tin shows a chemical similarity to both of its neighbors in group 14, germanium and lead, and has two main oxidation states, +2 and the slightly more stable +4. Tin is the 49th most abundance of the chemical elements, abundant element on Earth, making up 0.00022% of its crust, and with 10 stable isotopes, it has the largest number of stable isotopes in the periodic table, due to its magic number (physics), magic number of protons. It has two main allotrop ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Tin Pest
Tin pest is an autocatalytic, allotropic transformation of the element tin, which causes deterioration of tin objects at low temperatures. Tin pest has also been called ''tin disease'', ''tin blight'', ''tin plague'', or ''tin leprosy''. It is an autocatalytic process, accelerating once it begins. It was first documented in the scientific literature in 1851, having been observed in the pipes of pipe organs in medieval churches that had experienced cool climates. With the adoption of the Restriction of Hazardous Substances Directive (RoHS) regulations in Europe, and similar regulations elsewhere, traditional lead/tin solder alloys in electronic devices have been replaced by nearly pure tin, introducing tin pest and related problems such as tin whiskers. Allotropic transformation At and below, pure tin transforms from the silvery, ductile metallic allotrope of β-form ''white tin'' to the brittle, nonmetallic, α-form ''grey tin'' with a diamond cubic structure. The transformat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Tetragonal Crystal System
In crystallography, the tetragonal crystal system is one of the 7 crystal systems. Tetragonal crystal lattices result from stretching a cubic lattice along one of its lattice vectors, so that the cube becomes a rectangular prism with a square base (''a'' by ''a'') and height (''c'', which is different from ''a''). Bravais lattices There are two tetragonal Bravais lattices: the primitive tetragonal and the body-centered tetragonal. The body-centered tetragonal lattice is equivalent to the primitive tetragonal lattice with a smaller unit cell, while the face-centered tetragonal lattice is equivalent to the body-centered tetragonal lattice with a smaller unit cell. Crystal classes The point groups that fall under this crystal system are listed below, followed by their representations in international notation, Schoenflies notation, orbifold notation, Coxeter notation and mineral examples.Hurlbut, Cornelius S.; Klein, Cornelis, 1985, ''Manual of Mineralogy'', 20th ed ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
