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Vertical Roller Mill
Vertical roller mill is a type of grinder used to grind materials into extremely fine powder for use in mineral dressing processes, paints, pyrotechnics, cements and ceramics. It is an energy efficient alternative for a ball mill. Overview Vertical roller mill is a kind of grinding machine for cement, raw material, cement clinker, slag and coal slag. It has the features of simple structure and low cost of manufacture and use. Vertical roller mill has many different forms, but it works basically the same. All of these forms of machine come with a roller (or the equivalent of roller grinding parts), and roller along the track of the disc at the level of circular movement imposed by external grinding roller in the vertical pressure on the disc on the material being the joint action of compression and shear, and to crush. Operation Material grinding process motor through reducer rotating drive disc, the material falls from the mill under the central entrance and exit, under th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Milling (grinding)
A mill is a device, often a structure, machine or kitchen appliance, that breaks solid materials into smaller pieces by grinding, crushing, or cutting. Such comminution is an important unit operation in many processes. There are many different types of mills and many types of materials processed in them. Historically mills were powered by hand or by animals (e.g., via a hand crank), working animal (e.g., horse mill), wind (windmill) or water (watermill). In modern era, they are usually powered by electricity. The grinding of solid materials occurs through mechanical forces that break up the structure by overcoming the interior bonding forces. After the grinding the state of the solid is changed: the grain size, the grain size disposition and the grain shape. Milling also refers to the process of breaking down, separating, sizing, or classifying aggregate material (e.g. mining ore). For instance rock crushing or grinding to produce uniform aggregate size for construction purpo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Powder
A powder is a dry, bulk solid composed of many very fine particles that may flow freely when shaken or tilted. Powders are a special sub-class of granular materials, although the terms ''powder'' and ''granular'' are sometimes used to distinguish separate classes of material. In particular, ''powders'' refer to those granular materials that have the finer grain sizes, and that therefore have a greater tendency to form clumps when flowing. ''Granulars'' refers to the coarser granular materials that do not tend to form clumps except when wet. Types Many manufactured goods come in powder form, such as flour, sugar, ground coffee, powdered milk, copy machine toner, gunpowder, cosmetic powders, and some pharmaceuticals. In nature, dust, fine sand and snow, volcanic ash, and the top layer of the lunar regolith are also examples. Because of their importance to industry, medicine and earth science, powders have been studied in great detail by chemical engineers, mechanical engi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mineral Processing
In the field of extractive metallurgy, mineral processing, also known as ore dressing, is the process of separating commercially valuable minerals from their ores. History Before the advent of heavy machinery the raw ore was broken up using hammers wielded by hand, a process called "spalling". Before long, mechanical means were found to achieve this. For instance, stamp mills were used in Samarkand as early as 973. They were also in use in medieval Persia. By the 11th century, stamp mills were in widespread use throughout the medieval Islamic world, from Islamic Spain and North Africa in the west to Central Asia in the east. A later example was the Cornish stamps, consisting of a series of iron hammers mounted in a vertical frame, raised by cams on the shaft of a waterwheel and falling onto the ore under gravity. The simplest method of separating ore from gangue consists of picking out the individual crystals of each. This is a very tedious process, particularly when the in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paint
Paint is any pigmented liquid, liquefiable, or solid mastic composition that, after application to a substrate in a thin layer, converts to a solid film. It is most commonly used to protect, color, or provide texture. Paint can be made in many colors—and in many different types. Paint is typically stored, sold, and applied as a liquid, but most types dry into a solid. Most paints are either oil-based or water-based and each has distinct characteristics. For one, it is illegal in most municipalities to discard oil-based paint down household drains or sewers. Clean-up solvents are also different for water-based paint than they are for oil-based paint. Water-based paints and oil-based paints will cure differently based on the outside ambient temperature of the object being painted (such as a house.) Usually, the object being painted must be over , although some manufacturers of external paints/primers claim they can be applied when temperatures are as low as . History Paint was ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pyrotechnics
Pyrotechnics is the science and craft of creating such things as fireworks, safety matches, oxygen candles, explosive bolts and other fasteners, parts of automotive airbags, as well as gas-pressure blasting in mining, quarrying, and demolition. This trade relies upon self-contained and self-sustained exothermic chemical reactions to make heat, light, gas, smoke and/or sound. The name comes from the Greek words ''pyr'' ("fire") and ''tekhnikos'' ("made by art"). People responsible for the safe storage, handling, and functioning of pyrotechnic devices are known as pyrotechnicians. Proximate pyrotechnics Explosions, flashes, smoke, flames, fireworks and other pyrotechnic-driven effects used in the entertainment industry are referred to as proximate pyrotechnics. Proximate refers to the pyrotechnic device's location relative to an audience. In the majority of jurisdictions, special training and licensing must be obtained from local authorities to legally prepare and use proximate ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cement
A cement is a binder, a chemical substance used for construction that sets, hardens, and adheres to other materials to bind them together. Cement is seldom used on its own, but rather to bind sand and gravel ( aggregate) together. Cement mixed with fine aggregate produces mortar for masonry, or with sand and gravel, produces concrete. Concrete is the most widely used material in existence and is behind only water as the planet's most-consumed resource. Cements used in construction are usually inorganic, often lime or calcium silicate based, which can be characterized as hydraulic or the less common non-hydraulic, depending on the ability of the cement to set in the presence of water (see hydraulic and non-hydraulic lime plaster). Hydraulic cements (e.g., Portland cement) set and become adhesive through a chemical reaction between the dry ingredients and water. The chemical reaction results in mineral hydrates that are not very water-soluble and so are quite durable in wa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ball Mill
A ball mill is a type of grinder used to grind or blend materials for use in mineral dressing processes, paints, pyrotechnics, ceramics, and selective laser sintering. It works on the principle of impact and attrition: size reduction is done by impact as the balls drop from near the top of the shell. A ball mill consists of a hollow cylindrical shell rotating about its axis. The axis of the shell may be either horizontal or at a small angle to the horizontal. It is partially filled with balls. The grinding media are the balls, which may be made of steel (chrome steel), stainless steel, ceramic, or rubber. The inner surface of the cylindrical shell is usually lined with an abrasion-resistant material such as manganese steel or rubber lining. Less wear takes place in rubber lined mills. The length of the mill is approximately equal to its diameter. The general idea behind the ball mill is an ancient one, but it was not until the industrial revolution and the invention of s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cement Clinker
200px, Typical clinker nodules 200px, Hot clinker Cement clinker is a solid material produced in the manufacture of Portland cement as an intermediary product. Clinker occurs as lumps or nodules, usually to in diameter. It is produced by sintering (fusing together without melting to the point of liquefaction) limestone and aluminosilicate materials such as clay during the cement kiln stage. Composition and preparation The Portland clinker essentially consists of four mineral phases: two calcium silicates, alite (Ca3Si) and belite (Ca2Si), along with tricalcium aluminate (Ca3Al) and calcium aluminoferrite (Ca4AlFe). These main mineral phases are produced by heating at high temperature clays and limestone. Portland cement clinker is made by heating a homogeneous mixture of raw materials in a rotary kiln at high temperature. The products of the chemical reaction aggregate together at their sintering temperature, about . Aluminium oxide and iron oxide are present only as a f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Slag
Slag is a by-product of smelting (pyrometallurgical) ores and used metals. Broadly, it can be classified as ferrous (by-products of processing iron and steel), ferroalloy (by-product of ferroalloy production) or non-ferrous/base metals (by-products of recovering non-ferrous materials like copper, nickel, zinc and phosphorus). Within these general categories, slags can be further categorized by their precursor and processing conditions (e.g., Blast furnace (BF) slags, air-cooled blast furnace (ACBF) slag, basic oxygen furnace (BOF) slag, and electric arc furnace (EAF) slag) . Due to the large demand for these materials, slag production has also significantly increased throughout the years despite recycling (most notably in the iron and steelmaking industries) and upcycling efforts. The World Steel Association (WSA) estimates that 600 kg of by-products (~90 wt% is slags) are generated per tonne of steel produced. Composition Slag is usually a mixture of metal oxides and sili ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Roller Mill
Roller mills are mills that use cylindrical rollers, either in opposing pairs or against flat plates, to crush or grind various materials, such as grain, ore, gravel, plastic, and others. Roller grain mills are an alternative to traditional millstone arrangements in gristmills. Roller mills for rock complement other types of mills, such as ball mills and hammermills, in such industries as the mining and processing of ore and construction aggregate; cement milling; and recycling. Types Two-roller mills Two-roller mills are the simplest variety, in which the material is crushed between two rollers before it continues on to its final destination. The spacing between these two rollers can be adjusted by the operator. Thinner spacing usually leads to that material being crushed into smaller pieces. Four-roller mills Four-roller mills have two sets of rollers. When using a four-roller mill to mill grain, the grain first goes through rollers with a rather wide gap, which se ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vertical Roller Mill
Vertical roller mill is a type of grinder used to grind materials into extremely fine powder for use in mineral dressing processes, paints, pyrotechnics, cements and ceramics. It is an energy efficient alternative for a ball mill. Overview Vertical roller mill is a kind of grinding machine for cement, raw material, cement clinker, slag and coal slag. It has the features of simple structure and low cost of manufacture and use. Vertical roller mill has many different forms, but it works basically the same. All of these forms of machine come with a roller (or the equivalent of roller grinding parts), and roller along the track of the disc at the level of circular movement imposed by external grinding roller in the vertical pressure on the disc on the material being the joint action of compression and shear, and to crush. Operation Material grinding process motor through reducer rotating drive disc, the material falls from the mill under the central entrance and exit, under th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
