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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 their ore ... [...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 their ore ... [...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 al ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aluminium Dross2
Aluminium (aluminum in American and Canadian English) is a chemical element with the symbol Al and atomic number 13. Aluminium has a density lower than those of other common metals, at approximately one third that of steel. It has a great affinity towards oxygen, and forms a protective layer of oxide on the surface when exposed to air. Aluminium visually resembles silver, both in its color and in its great ability to reflect light. It is soft, non-magnetic and ductile. It has one stable isotope, 27Al; this isotope is very common, making aluminium the twelfth most common element in the Universe. The radioactivity of 26Al is used in radiodating. Chemically, aluminium is a post-transition metal in the boron group; as is common for the group, aluminium forms compounds primarily in the +3 oxidation state. The aluminium cation Al3+ is small and highly charged; as such, it is polarizing, and bonds aluminium forms tend towards covalency. The strong affinity towards oxyg ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aluminium
Aluminium (aluminum in American and Canadian English) is a chemical element with the symbol Al and atomic number 13. Aluminium has a density lower than those of other common metals, at approximately one third that of steel. It has a great affinity towards oxygen, and forms a protective layer of oxide on the surface when exposed to air. Aluminium visually resembles silver, both in its color and in its great ability to reflect light. It is soft, non-magnetic and ductile. It has one stable isotope, 27Al; this isotope is very common, making aluminium the twelfth most common element in the Universe. The radioactivity of 26Al is used in radiodating. Chemically, aluminium is a post-transition metal in the boron group; as is common for the group, aluminium forms compounds primarily in the +3 oxidation state. The aluminium cation Al3+ is small and highly charged; as such, it is polarizing, and bonds aluminium forms tend towards covalency. The strong affinity tow ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lead
Lead is a chemical element with the symbol Pb (from the Latin ) and atomic number 82. It is a heavy metal that is denser than most common materials. Lead is soft and malleable, and also has a relatively low melting point. When freshly cut, lead is a shiny gray with a hint of blue. It tarnishes to a dull gray color when exposed to air. Lead has the highest atomic number of any stable element and three of its isotopes are endpoints of major nuclear decay chains of heavier elements. Lead is toxic, even in small amounts, especially to children. Lead is a relatively unreactive post-transition metal. Its weak metallic character is illustrated by its amphoteric nature; lead and lead oxides react with acids and bases, and it tends to form covalent bonds. Compounds of lead are usually found in the +2 oxidation state rather than the +4 state common with lighter members of the carbon group. Exceptions are mostly limited to organolead compounds. Like the lighter members of the ... [...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 t ... [...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 is ... [...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 obsole ... [...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] |
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 gets m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Corvée
Corvée () is a form of unpaid, forced labour, that is intermittent in nature lasting for limited periods of time: typically for only a certain number of days' work each year. Statute labour is a corvée imposed by a state for the purposes of public works. As such it represents a form of levy (taxation). Unlike other forms of levy, such as a tithe, a corvée does not require the population to have land, crops or cash. The obligation for tenant farmers to perform corvée work for landlords on private landed estates was widespread throughout history before the Industrial Revolution. The term is most typically used in reference to medieval and early modern Europe, where work was often expected by a feudal landowner (of their vassals), or by a monarch of their subjects. The application of the term is not limited to that time or place; the corvée has existed in modern and ancient Egypt, ancient Sumer, ancient Rome, China, Japan, everywhere in continental Europe, the Incan civi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lion's Share
The lion's share is an idiomatic expression which now refers to the major share of something. The phrase derives from the plot of a number of fables ascribed to Aesop and is used here as their generic title. There are two main types of story, which exist in several different versions. Other fables exist in the East that feature division of prey in such a way that the divider gains the greater part - or even the whole. In English the phrase used in the sense of ''nearly all'' only appeared at the end of the 18th century; the French equivalent, ''le partage du lion'', is recorded from the start of that century, following La Fontaine's version of the fable. The Phaedrus version The early Latin version of Phaedrus begins with the reflection that "Partnership with the mighty is never trustworthy". It then relates how a cow, a goat and a sheep go hunting together with a lion. When it comes to dividing the spoil, the lion says, "I take the first portion because of my title, since I ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
