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Dross
Dross is a mass of solid impurities floating on a molten metal or dispersed in the metal, such as in wrought iron. It forms on the surface of low-melting-point metals such as tin, lead, zinc or aluminium or alloys by oxidation of the metal. For higher melting point metals and alloys such as steel and silver, oxidized impurities melt and float making them easy to pour off. With wrought iron, hammering and later rolling remove some dross. With tin and lead the dross can be removed by adding sodium hydroxide pellets, which dissolve the oxides and form a slag. If floating, dross can also be skimmed off. Dross, as a solid, is distinguished from slag, which is a liquid. Dross product is not entirely waste material; for example, aluminium dross can be recycled and is also used in secondary steelmaking for slag deoxidation. Etymology and usage The term ''dross'' derives from the Old English word ''dros'', meaning the scum produced when smelting metals (extracting them from ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aluminium Dross Recycling
Aluminium dross, a byproduct of the aluminium smelting process, can be mechanically recycled to separate the residual aluminium metal from the aluminium oxide. Thermo-mechanical metal extraction The mechanical process of recycling does not use any toxic chemicals previously used in the process of extracting the valuable aluminium in the dross. Hot dross processing is a system whereby the majority of metal is recovered without chemically reducing the aluminium oxides. The dross is first crushed then separated into aluminium metal rich particles and aluminium oxide rich particles based on density. The metal rich particles are then melted in a furnace to remove the remaining oxide particles. Mechanical extraction vs chemical The recovery of aluminium metal from dross has traditionally caused severe environmental issue with highly alkaline waste waters, a waste product that is rich in waste flux and that evolves ammonia gas on contact with water and can spontaneously combust if a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dross
Dross is a mass of solid impurities floating on a molten metal or dispersed in the metal, such as in wrought iron. It forms on the surface of low-melting-point metals such as tin, lead, zinc or aluminium or alloys by oxidation of the metal. For higher melting point metals and alloys such as steel and silver, oxidized impurities melt and float making them easy to pour off. With wrought iron, hammering and later rolling remove some dross. With tin and lead the dross can be removed by adding sodium hydroxide pellets, which dissolve the oxides and form a slag. If floating, dross can also be skimmed off. Dross, as a solid, is distinguished from slag, which is a liquid. Dross product is not entirely waste material; for example, aluminium dross can be recycled and is also used in secondary steelmaking for slag deoxidation. Etymology and usage The term ''dross'' derives from the Old English word ''dros'', meaning the scum produced when smelting metals (extracting them from ... [...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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Impurity
In chemistry and materials science, impurities are chemical substances inside a confined amount of liquid, gas, or solid, which differ from the chemical composition of the material or compound. Firstly, a pure chemical should appear thermodynamically in at least one chemical phase and can also be characterized by its one-component- phase diagram. Secondly, practically speaking, a pure chemical should prove to be homogeneous (i.e., will show no change of properties after undergoing a wide variety of consecutive analytical chemical procedures). The perfect pure chemical will pass all attempts and tests of further separation and purification. Thirdly, and here we focus on the common chemical definition, it should not contain any trace of any other kind of chemical species. In reality, there are no absolutely 100% pure chemical compounds, as there is always some minute contamination. Indeed, as detection limits in analytical chemistry decrease, the number of impurities detected t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Molten Metal
Melting, or fusion, is a physical process that results in the phase transition of a substance from a solid to a liquid. This occurs when the internal energy of the solid increases, typically by the application of heat or pressure, which increases the substance's temperature to the melting point. At the melting point, the ordering of ions or molecules in the solid breaks down to a less ordered state, and the solid "melts" to become a liquid. Substances in the molten state generally have reduced viscosity as the temperature increases. An exception to this principle is the element sulfur, whose viscosity increases in the range of 160 °C to 180 °C due to polymerization. Some organic compounds melt through mesophases, states of partial order between solid and liquid. First order phase transition From a thermodynamics point of view, at the melting point the change in Gibbs free energy ''∆G'' of the substances is zero, but there are non-zero changes in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Deoxidizer
Deoxidization is a method used in metallurgy to remove the oxygen content during steel manufacturing. In contrast, antioxidants are used for stabilization, such as in the storage of food. Deoxidation is important in the steelmaking process as oxygen is often detrimental to the quality of steel produced. Deoxidization is mainly achieved by adding a separate chemical species to neutralize the effects of oxygen or by directly removing the oxygen. Oxidation Oxidation is the process of an element losing electrons. For example, iron will transfer two of its electrons to oxygen, forming an oxide. This occurs all throughout as an unintended part of the steelmaking process. Oxygen blowing is a method of steelmaking where oxygen is blown through pig iron to lower the carbon content. Oxygen forms oxides with the unwanted elements, such as carbon, silicon, phosphorus, and manganese, which appear from various stages of the manufacturing process. These oxides will float to the top of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aluminium Alloy Inclusions
An inclusion is a solid particle in liquid aluminium alloy. It is usually non-metallic and can be of different nature depending on its source. Problems related to inclusions Inclusions can create problems in the casting when they are large and in too high concentration. Here are examples of problems related to inclusions: * Pinholes in light gauge foil * Flange cracks in beverage containers * Surface streaks in bright automotive trim and lithographic material * Breakage in wire drawing operation * Increased tool wear and tear * Increased porosity * Loss of pressure tightness of engine blocks * Poor machinability * Cosmetic defect in apparent surfaces * Diminished mechanical properties (e.g. Ultimate Tensile Strength, Yield Strength, Elongation) Inclusion types Oxide films In contact with ambient air, liquid aluminium reacts with the oxygen and form an oxide film layer (gamma-Al2O3). This layer becomes thicker with time. When molten aluminium is disturbed, this oxide film g ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dogsbody
A dogsbody, dog's body, or less commonly dog robber is someone who does menial or drudge work.''Oxford English Dictionary'', 3rd edition, 2010''s.v.''/ref> Originally, in the British Royal Navy, a dogsbody was a semi-sarcastic colloquialism for a junior officer or midshipman. A batman has a similar function. A rough American equivalent would be a package-handler, gofer, grunt, lackey, or workhorse. History The Royal Navy used dried peas boiled in a bag ( pease pudding) as one of their staple foods circa the early 19th century. Sailors nicknamed this item "dog's body". In the early 20th century, junior officers and midshipmen who performed jobs that more senior officers did not want to do began to be called "dogsbodies". The term became more common in non-naval usage c. 1930, referring to people who were stuck with rough work. The term "dogsbody" has not always been derogatory, with a number of people deliberately using it as their callsign or handle. The most famous of these i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Solid
Solid is one of the four fundamental states of matter (the others being liquid, gas, and plasma). The molecules in a solid are closely packed together and contain the least amount of kinetic energy. A solid is characterized by structural rigidity and resistance to a force applied to the surface. Unlike a liquid, a solid object does not flow to take on the shape of its container, nor does it expand to fill the entire available volume like a gas. The atoms in a solid are bound to each other, either in a regular geometric lattice ( crystalline solids, which include metals and ordinary ice), or irregularly (an amorphous solid such as common window glass). Solids cannot be compressed with little pressure whereas gases can be compressed with little pressure because the molecules in a gas are loosely packed. The branch of physics that deals with solids is called solid-state physics, and is the main branch of condensed matter physics (which also includes liquids). Materials ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Archaism
In language, an archaism (from the grc, ἀρχαϊκός, ''archaïkós'', 'old-fashioned, antiquated', ultimately , ''archaîos'', 'from the beginning, ancient') is a word, a sense of a word, or a style of speech or writing that belongs to a historical epoch long beyond living memory, but that has survived in a few practical settings or affairs. Lexical archaisms are single archaic words or expressions used regularly in an affair (e.g. religion or law) or freely; literary archaism is the survival of archaic language in a traditional literary text such as a nursery rhyme or the deliberate use of a style characteristic of an earlier age—for example, in his 1960 novel '' The Sot-Weed Factor'', John Barth writes in an 18th-century style. Archaic words or expressions may have distinctive emotional connotations—some can be humorous (''forsooth''), some highly formal (''What say you?''), and some solemn (''With thee do I plight my troth''). A distinction between archaic and obs ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Drudgery
A laborer (or labourer) is a person who works in manual labor types in the construction industry workforce. Laborers are in a working class of wage-earners in which their only possession of significant material value is their labor. Industries employing laborers include building things such as roads, buildings, bridges, tunnels, and railway tracks. Laborers work with blasting tools, hand tools, power tools, air tools, and small heavy equipment, and act as assistants to other trades as well such as operators or cement masons. The 1st century BC engineer Vitruvius writes that a good crew of laborers is just as valuable as any other aspect of construction. Other than the addition of pneumatics, laborer practices have changed little. With the introduction of field technologies, the laborers have been quick to adapt to the use of this technology as being laborers' work. Tools and equipment The following tools are considered a minimum for a laborer to keep with them: hammer, plier ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
