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Forest Glass
Forest glass (''Waldglas'' in German) is a type of medieval glass produced in northwestern and central Europe from approximately 1000–1700 AD using wood ash and sand as the main raw materials and made in factories known as glasshouses in forest areas.Tait, H., 1991. It is characterized by a variety of greenish-yellow colors, the earlier products often being of crude design and poor quality, and was used mainly for everyday vessels and increasingly for ecclesiastical stained glass windows. Its composition and manufacture contrast sharply with Roman and pre-Roman glassmaking, centered on Mediterranean and contemporaneous Byzantine and Islamic glassmaking to the east. History While under Roman rule, the raw materials and manufacturing methods of northern Europe were those of the Roman tradition, using the mineral natron. For several centuries after the fall of the Western Roman Empire, around 450 AD, recycling of Roman glass formed the major part of the local industry and glass ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Roemer Waldglas
Romer, Römer, Roemer, or similar may refer to: * Romer (surname), includes a list of people with the name * Romer (tool), a cartographic device also known as a reference card * Rømer scale, a disused temperature scale named after Ole Rømer * Römer, a medieval building in Frankfurt am Main * Römer (crater), a lunar crater * Romer arm, an industrial measuring device * Romer v. Evans, a United States Supreme Court case dealing with civil rights and state laws * Romer's gap in the record of vertebrate fossils c. 360–340 million years ago * Romer Shoal Light, a lighthouse off the coast of New Jersey, United States * Römer (glass), also rummer or roemer, a type of drinking glass popular in early modern Europe See also * Roamer (other) * Rohmer, surname {{disambig, surname ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Flux (metallurgy)
In metallurgy, a flux is a chemical reducing agent, flowing agent, or purifying agent. Fluxes may have more than one function at a time. They are used in both extractive metallurgy and metal joining. Some of the earliest known fluxes were sodium carbonate, potash, charcoal, coke, borax, lime, lead sulfide and certain minerals containing phosphorus. Iron ore was also used as a flux in the smelting of copper. These agents served various functions, the simplest being a reducing agent, which prevented oxides from forming on the surface of the molten metal, while others absorbed impurities into slag, which could be scraped off molten metal. Fluxes are also used in foundries for removing impurities from molten nonferrous metals such as aluminium, or for adding desirable trace elements such as titanium. As reducing agents, fluxes facilitate soldering, brazing, and welding by removing oxidation from the metals to be joined. In some applications molten flux also serves as ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Manganese
Manganese is a chemical element; it has Symbol (chemistry), symbol Mn and atomic number 25. It is a hard, brittle, silvery metal, often found in minerals in combination with iron. Manganese was first isolated in the 1770s. It is a transition metal with a multifaceted array of industrial alloy uses, particularly in stainless steels. It improves strength, workability, and resistance to wear. Manganese oxide is used as an oxidising agent, as a rubber additive, and in glass making, fertilisers, and ceramics. Manganese sulfate can be used as a fungicide. Manganese is also an essential human dietary element, important in macronutrient metabolism, bone formation, and free radical defense systems. It is a critical component in dozens of proteins and enzymes. It is found mostly in the bones, but also the liver, kidneys, and brain. In the human brain, the manganese is bound to manganese metalloproteins, most notably glutamine synthetase in astrocytes. Manganese is commonly found in labo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cobalt
Cobalt is a chemical element; it has Symbol (chemistry), symbol Co and atomic number 27. As with nickel, cobalt is found in the Earth's crust only in a chemically combined form, save for small deposits found in alloys of natural meteoric iron. The free element, produced by reductive smelting, is a hard, lustrous, somewhat brittle, gray metal. Cobalt-based blue pigments (cobalt blue) have been used since antiquity for jewelry and paints, and to impart a distinctive blue tint to glass. The color was long thought to be due to the metal bismuth. Miners had long used the name ''kobold ore'' (German language, German for ''goblin ore'') for some of the blue pigment-producing minerals. They were so named because they were poor in known metals and gave off poisonous arsenic-containing fumes when smelted. In 1735, such ores were found to be reducible to a new metal (the first discovered since ancient times), which was ultimately named for the ''kobold''. Today, some cobalt is produced sp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Copper
Copper is a chemical element; it has symbol Cu (from Latin ) and atomic number 29. It is a soft, malleable, and ductile metal with very high thermal and electrical conductivity. A freshly exposed surface of pure copper has a pinkish-orange color. Copper is used as a conductor of heat and electricity, as a building material, and as a constituent of various metal alloys, such as sterling silver used in jewelry, cupronickel used to make marine hardware and coins, and constantan used in strain gauges and thermocouples for temperature measurement. Copper is one of the few metals that can occur in nature in a directly usable, unalloyed metallic form. This means that copper is a native metal. This led to very early human use in several regions, from . Thousands of years later, it was the first metal to be smelted from sulfide ores, ; the first metal to be cast into a shape in a mold, ; and the first metal to be purposely alloyed with another metal, tin, to create bronze, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Iron
Iron is a chemical element; it has symbol Fe () and atomic number 26. It is a metal that belongs to the first transition series and group 8 of the periodic table. It is, by mass, the most common element on Earth, forming much of Earth's outer and inner core. It is the fourth most abundant element in the Earth's crust, being mainly deposited by meteorites in its metallic state. Extracting usable metal from iron ores requires kilns or furnaces capable of reaching , about 500 °C (900 °F) higher than that required to smelt copper. Humans started to master that process in Eurasia during the 2nd millennium BC and the use of iron tools and weapons began to displace copper alloys – in some regions, only around 1200 BC. That event is considered the transition from the Bronze Age to the Iron Age. In the modern world, iron alloys, such as steel, stainless steel, cast iron and special steels, are by far the most common industrial metals, due to their mechan ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Slag Heap
A spoil tip (also called a boney pile, culm bank, gob pile, waste tip or bing) is a pile built of accumulated ''spoil'' – waste material removed during mining. Spoil tips are not formed of slag, but in some areas, such as England and Wales, they are referred to as slag heaps. In Scotland the word ''bing'' is used. In North American English the term is mine dump or mine waste dump. The term "spoil" is also used to refer to material removed when digging a foundation, tunnel, or other large excavation. Such material may be ordinary soil and rocks (after Coal preparation plant, separation of coal from waste), or may be heavily contaminated with chemical waste, determining how it may be disposed of. Clean spoil may be used for land reclamation. Spoil is distinct from tailings, which is the processed material that remains after the valuable components have been extracted from ore. Etymology The phrase originates from the French word ''espoilelier'', a verb conveying the meanin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Opacifier
An opacifier is a substance added to a material in order to make the ensuing system opaque. An example of a chemical opacifier is titanium dioxide (TiO2), which is used as an opacifier in paints, in paper, and in plastics. It has very high refraction index (rutile modification 2.7 and anatase modification 2.55) and optimum refraction is obtained with crystals about 225 nanometers. Impurities in the crystal alter the optical properties. It is also used to opacify ceramic glazes and milk glass; bone ash is also used. Opacifiers must have a refractive index (RI) substantially different from the system. Conversely, clarity may be achieved in a system by choosing components with very similar refractive indices. Glasses Ancient milk glasses used crystals of calcium antimonate, formed in the melt from calcium present in the glass and an antimony additive. Opaque yellow glasses contained crystals of lead antimonate; bindheimite mineral may have been used as the additive. Under oxidiz ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Magnesium Oxide
Magnesium oxide (MgO), or magnesia, is a white hygroscopic solid mineral that occurs naturally as periclase and is a source of magnesium (see also oxide). It has an empirical formula of MgO and consists of a lattice of Mg2+ ions and O2− ions held together by ionic bonding. Magnesium hydroxide forms in the presence of water (MgO + H2O → Mg(OH)2), but it can be reversed by heating it to remove moisture. Magnesium oxide was historically known as magnesia alba (literally, the white mineral from Magnesia), to differentiate it from '' magnesia nigra'', a black mineral containing what is now known as manganese. Related oxides While "magnesium oxide" normally refers to MgO, the compound magnesium peroxide MgO2 is also known. According to evolutionary crystal structure prediction, MgO2 is thermodynamically stable at pressures above 116 GPa (gigapascals), and a semiconducting suboxide Mg3O2 is thermodynamically stable above 500 GPa. Because of its stability, MgO is used as a mod ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alumina
Aluminium oxide (or aluminium(III) oxide) is a chemical compound of aluminium and oxygen with the chemical formula . It is the most commonly occurring of several aluminium oxides, and specifically identified as aluminium oxide. It is commonly called alumina and may also be called aloxide, aloxite, ALOX or alundum in various forms and applications and alumina is refined from bauxite. It occurs naturally in its crystalline polymorphic phase α-Al2O3 as the mineral corundum, varieties of which form the precious gemstones ruby and sapphire,which have an alumina content approaching 100%. Al2O3 is used as feedstock to produce aluminium metal, as an abrasive owing to its hardness, and as a refractory material owing to its high melting point. Natural occurrence Corundum is the most common naturally occurring crystalline form of aluminium oxide. Rubies and sapphires are gem-quality forms of corundum, which owe their characteristic colours to trace impurities. Rubies are given their ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Calcium Oxide
Calcium oxide (formula: Ca O), commonly known as quicklime or burnt lime, is a widely used chemical compound. It is a white, caustic, alkaline, crystalline solid at room temperature. The broadly used term '' lime'' connotes calcium-containing inorganic compounds, in which carbonates, oxides, and hydroxides of calcium, silicon, magnesium, aluminium, and iron predominate. By contrast, ''quicklime'' specifically applies to the single compound calcium oxide. Calcium oxide that survives processing without reacting in building products, such as cement, is called free lime. Quicklime is relatively inexpensive. Both it and the chemical derivative calcium hydroxide (of which quicklime is the base anhydride) are important commodity chemicals. Preparation Calcium oxide is usually made by the thermal decomposition of materials, such as limestone or seashells, that contain calcium carbonate (CaCO3; mineral calcite) in a lime kiln. This is accomplished by heating the material to above , ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Potash
Potash ( ) includes various mined and manufactured salts that contain potassium in water- soluble form.Potash , USGS 2008 Minerals Yearbook The name derives from ''pot ash'', plant ashes or soaked in water in a pot, the primary means of manufacturing potash before the Industrial Era. The word '''' is derived from ''potash''. Potash is produced worldwide in amounts exceeding 71.9 million |
