charcoal (lat. carbo ligni, frz. charbon de bois, English. charcoal, I. carbons legna, S. carbón de madera) develops, if air-dry wood (dried on 13-18% water) under luftabschluss - and/or. without oxygenation up275° is heated up, then the temperature continues to rise automatically to 350-400° (Holzverkohlung, coking). As arrears one receives beside gaseous decomposition products (see.Wood spirit) approx. 35% charcoal. The volatile components of the wood burn.
The charcoal is not by any means pure carbon,separate a complicated mixture of organic compounds with 81-90% carbon, 3% hydrogen, 6% oxygen, 1% nitrogen, 6% humidity and 1-2% ash. The charcoal forms a loose, black product with the apparent density of 450 kg/m ³ (porously) and the true density of 1.400 kg/m ³ (nonporously). Because of the many microscopically small niches, recesses, channels etc. (Porenvolumen 70-85%, internal surface 50-80m2/Gramm) you come a high adsorption capacity. It can be ignited relatively easily (200-250°) and burns without flamefurther, because the flame-forming gases already escaped with the carbonization are. Per kg of charcoal about 29-33 MJ at energy become free with the burn. It burns sulfur-free.
Charcoal, of them finely arranged surfacemany unwanted organic substances binds, can also as activated charcoal for filtering and cleaning various materials be used; z. B. during the production of Wodka or as Kohlekompretten with failure.
Meyers encyclopedia 1888/9:
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Coal is the product of the heating of vegetable and animal materialsLuftabschluss. All vegetable and animal materials consist of carbon, hydrogen and oxygen, and many contain also nitrogen. If one heats it up at the time of conclusion of air, then they decompose under education of volatile connections, by which the largest partthe hydrogen, oxygen, possibly also the nitrogen in the form of carbon compounds one continues, and, often under preservation of the structure, a black remainder, the coal, which consists predominantly of carbon and depending upon the temperature, remains, it was exposed to which,more or less water and oxygen, possibly also nitrogen contain.
similar decomposition is subject the organic substance with that process, its first products peat and brown coal and its stops Hard coal and anthracite coal (perhaps also graphite) are. Also here a carbon-rich, water and oxygen-poor product, is formed the fossil coal; but the process does not progress so far that by heating still volatile wasserstoffhaltige connections could not be driven out.The carbon-rich arrears of such operation are those coke (S. D.). With each carbonization process developing volatile decomposition products, which consist mainly of carbon and hydrogen, are partially again decomposable with higher than their developing temperature, whereby them a part of theirCarbon separate.
A such separation is the Gaskohle (retort graphite), which at the hottest places of the retorts, in which illuminating gas, settles, as well as the soot, which separates itself gases forming with incomplete burn the flame, is represented. BecomeBody chars, which at the carbonization temperature melts (sugar, strength flour, glue), then develops a shining, blasige, very easily zerreibliche mass (gloss coal), while the K. not melting substances often still their structure shows, like the charcoal. The coal separated from gases(Gaskohle) and contain by carbonization the coal of pure received chemical compounds (for example sugars) only carbon, hydrogen and oxygen, while nitrogenous substances supply a nitrogenous coal and a usual planting and animal materials a coal, whatever more or less mineral materialscontains. These stay as ash, if one heats the coal up with Luftzutritt, until carbon is completely burned. Much ash and nitrogen-rich the bone char (f is. D.), which with the burn of their carbon content at air their structure invariablykeeps.
Charcoal is represented by heating up wood with Luftabschluss. The oldest method of the charcoal production (Kohlenbrennerei) is the Meilerbetrieb (Köhlerei), originating from the antiquity, with which the wood in approximately hemisphere or conical heap (Meilern) in large Scheiten(standing or lying) around three stakes (Quandel), established in the center, and covered with a cover by lawns, earth is put on regular and coal-small. Under this cover one leads the burn with carefully regulated Luftzutritt in the way,the fact that possibly no more woods burns than is quite necessary, in order to heat the entire wood mass up on the carbonization temperature. Essentially only the gases or steams developing from the wood heated up are to burn themselves. The carbonization is completed, which oneby the color of the escaping smoke recognizes, then one leaves the Meiler cooling and takes him apart (coal-pulled, coal-long). In heaps or lying works one particularly chars the wood in South Germany, Russia and Sweden. Also here the wood becomes inHeap laminated, but the carbonization takes place only gradually from an end of the oblong heap on the other hand, and the charred pieces are immediately pulled. Completely similarly as in Meilern or heaps runs the carbonization in round or angular bricked Meileröfen, whichan easier, more complete production of the by-products (tar, wood vinegar, which are lost with the Meilerbetrieb usually) to permit, but and a less good coal supply a smaller yield. With these furnaces, as with Meilern and heaps, air steps to the one which can be charredWood, and a part of the same produce the necessary temperature by its burn. One has however the carbonization process much more the under control and can him better lead, if one the wood in containers, which are heated from the outside, thus withoutLuftzutritt, chars. This happens in retorts, tubes or cylinders occasionally with air heated up, with blast furnace gases of the blast furnaces, with overheated water vapours or with use of induced air. Such a careful carbonization is particularly necessary for the production of coal for the gun powder production.In Spandau one uses large iron cylinders, which are filled outside of the furnace, locked with a cover and pushed into the furnace. A large mobile cover closes the area, in which the cylinder is. From the wood itselfdeveloping gases leads one into the firing. The temperature is determined by means of a pyrometer. Red coal for hunt powders is represented with overheated water vapour. As by-product one receives charcoal during the representation from illuminating gas from wood, during the representation from wood vinegar andwith the Teerschwelerei. Wood delivers only hygroscopic water with heating up to 150°; then sour steams develop, from 300° starting from ever more closely becoming yellow or yellow-brown steam and gases. With the cooling of the escaping products one receives tar and wood vinegar(which methanol contains). The yield at coal is all the smaller, the more highly the temperature was increased, and the coal becomes at the same time enriches steadily poorer in carbon and ash and accordingly at hydrogen and oxygen.
Between 270 and300° received product is brown (red coal, roasting coal), has with one around half grössern yield nearly the same effective value as the black coal received over 340° and for metallurgical purposes and because of certain characteristics for gun powder production often is therefore represented. With thatRise of the carbonization temperature grows the tightness and the line ability of the coal for warmth and electricity; however the inflammability of the coal and its inclination sink at the same time to tighten humidity.
One compares the apparent volume (without departure of the gaps) of the wood with that, then oakwood 71.8-74.3, red beech wood 73, Birkenholz 68.5, Föhrenholz 63.6 Proz supply hornbeam 57.3 to the coal with. K. After the real volume the coal yield amounts to on the average 47.6 per cent. If the wood is dried with 150° and charred with 300°, then one receivesWeight percentage K.: from oakwood 46, from fir wood 40.7,5, elm 34.7, Hain-buche 34.6, Birke 34.17, Faulbaum 33.6, ash 33.3, lime tree 31.85, Pappel 31.1, Rosskastanie 30,….
Resin-free, juice-rich wood does not give dull, most porous coal; the K received from harzigem, juice-rich wood.the gloss coal formed from the juice components contains inside the cells. Always charcoal is easily zerreiblich, but only due to its structure; the coal substance is hard and a good polishing agent for metal. At usual temperature it is most steady and liesfor many centuries in the soil, without changing; at air it absorbs avid gases and steams (S.Absorption) and from liquids loosened materials.
The Gewichtszunahme of fresh coal when being because of air amounts to in 24 hours with calibration andBirkenkohle 4 -5 per cent, spruce, booking, Erlenkohle 5-8 per cent, Kiefern, feasting, Pappelkohle 8-9 per cent, fir coal 16 per cent.
Generally represented coal absorbs most strongly at low temperature. Of the K. absorbed oxygen works strongly oxidizing, it changed for example hydrogen sulfide in sulfuric acid and water, ammonia into nitric ammonia, sulfur ammonium into sulfur-sour ammonia; also rot products are energetically destroyed, and with coal surrounded meat decomposes only after longer time and without rot features. Coal works odorless making, by absorbing smelling materials;evil-smelling, fauliges water is cleaned by freshly burned charcoal, released Weingeist from the Fuselöl. But the coal does not affect the microscopic organisms contained in the water (bacteria etc.), and with filtering the water by coal goes the same through the filter; thatWater becomes thus odorless, but not of the diseases organisms transfer-end released. Coal absorbs also coloring materials, especially the nitrogenous coal (bone char in first row) works strongly decolorizing. Beside the coloring materials also salts are absorbed by the coal, and on it are basedto a large extent the value of the bone char for the sugar production. Coal extracts the lime from the Kalkwasser, falls metal oxides, particularly those of the heavy metals, from the aqueous solutions of its salts or absorbs the latters invariably; Silver and cuprous salts are reduced by coal.Bitter materials, Glykoside, carbohydrates, alkaloids, are particularly absorbed likewise. When long being because of air it loses its absorptive capacity, attains it however again by burning; also the substances taken up from liquids can be extracted from the coal again (revival), so that itin particular after the burning following on it is again usable.
One uses charcoal for the production of intensive heat particularly anywhere, where smoke and flame formation must be avoided, for example in the forging fire, when the glowing making flat steel, with chemical operations, when heating up articlesin the room etc. Since it reduces metal oxides, it serves for the production of metals from the ores. Furthermore with the high price of the charcoal one seeks to replace these however as much as possible by hard coal or coke, charcoal serves forRepresentation of gun powder and steel, to the Entfuseln of the Branntweins, for clarifying and decolorizing liquids, for filtering the water, for conserving rotable substances, for disinfecting, for cleaning carbonic acid (for mineral waters), hydrogen, ranzigen fats and dumpfigem grain, as tooth powders, asPolishing agent for metals, for the filling of Aspiratoren for the use in areas, are present into which harmful gases. Water in barrels, which charred inwendig, remains for a very long time fresh.
In addition as fertilizer charcoal makes the soil and works throughtheir absorption capacity for ammonia and carbonic acid. Ornamental plants with putrid-end roots can be healed, if they are brought into earth mixed with coal. Large wounds at juice plants heal easily, if one covers them with coal powder, also can one such plants, tubersand seeds for long transport well in coal pack.
Retort graphite and in besonderm procedures bereitetete coke becomes galvanic batteries and the pole points with. electrical light uses. Animal coal serves in particular for decolorizing liquids. Some serve charring places asblack color (Frankfurt black, leg-black, Chinese india ink etc.), and lime tree and pasture coal for drawing are used.