Aluminum calcium oxide,

The choice of selected raw materials is very wide, but they must provide calcium oxide (lime), iron oxide [1309-37-1/, siHca, and aluminum oxide (alumina). Examples of the calcereous (calcium oxide) sources are calcium carbonate minerals (aragonite [14791-73-2] calcite [13397-26-7] limestone [1317-65-3] or mad), seasheUs, or shale. Examples of argillaceous (siHca and alumina) sources are clays, fly ash, mad, shale, and sand. The iron oxide commonly comes from iron ore, clays, or mill scale. Some raw matedals supply more than one ingredient, and the mixture of raw matedals is a function of their chemical composition, as deterrnined by cost and availabiHty. 

Aluminothermal Method. Calcium metal is produced by high temperature vacuum reduction of calcium oxide in the aluminothermal process. This process, in which aluminum [7429-90-5] metal serves as the reducing agent, was commercialized in the 1940s. The reactions, which are thermodynamically unfavorable at temperatures below 2000°C, have been summarized as ... 

The purity of commercial-grade calcium depends to a large extent on the purity of the calcium oxide used in its production. Impurities such as magnesium oxide, or other alkaline-earth or alkaH metal compounds are reduced along with the calcium oxide, and these metals can contaminate the calcium. In addition, small amounts of aluminum may distill with the calcium vapor, and small amounts of calcium nitride may be produced by reaction with atmospheric nitrogen. 

The chemical formula for limestone is CaCOj and upon burning forms calcium oxide (CaO), which is known as burnt lime. Calcium oxide, when mixed with water, forms calcium hydroxide (Ca(OH)2). Calcium hydroxide is used to treat water as a coagulation aid along with aluminum sulfate. 

Several methods are described for the production of tantalum and niobium metal. Metals can be obtained by reduction of pentachlorides with magnesium, sodium, hydrogen or by thermal decomposition in vacuum [24,28]. Oxides can be reduced using carbon, aluminum, calcium, magnesium [28, 537, 538] or alkali and rare earth metals [539]. 

As mentioned above, approximately 7% of the total sulfur present in lead ore is emitted as S02. The remainder is captured by the blast furnace slag. The blast furnace slag is composed primarily of iron and silicon oxides, as well as aluminum and calcium oxides. Other metals may also be present in smaller amounts, including antimony, arsenic, beryllium, cadmium, chromium, cobalt, copper, lead, manganese, mercury, molybdenum, silver, and zinc. This blast furnace slag is either recycled back into the process or disposed of in piles on site. About 50 to 60% of the recovery furnace output is slag and residual lead, which are both returned to the blast furnace. The remainder of this dross furnace output is sold to copper smelters for recovery of the copper and other precious metals. 

Laughing gas, see Nitrogen(I) oxide Lautarite, see Calcium iodate Lawrencite, see Iron(II) chloride Leehatelierite, see Silicon dioxide Lime, see Calcium oxide Litharge, see Lead(II) oxide Lithium aluminum hydride, see Lithium tetrahydri-doaluminate... 

Finely divided metals (without oxide film) Aluminum, calcium, cobalt, iron, magnesium, manganese, palladium, platinum, titanium, tin, zinc, zirconium... 

Fly ash - the primary components are silicon dioxide, aluminum oxide, iron oxide, and calcium oxide. Fifty million tons of fly ash are produced annually in the USA. About 76% is disposed of either onsite or in state-regulated disposal areas, while the rest is reclaimed. 

Calcium oxide was used in ancient times to make mortar for building with stone. Both the metal and calcium compounds have many industrial as well as biological uses. Metallic calcium is used as an alloy agent for copper and aluminum. It is also used to purify lead and is a reducing agent for beryllium. 

Currently, thermal reduction processes have replaced the electrolysis method. The starting material in these methods is limestone, which is calcined to produce calcium oxide. The latter is ground, mixed and compacted with aluminum, and reduced at temperatures between 1,000° to 1,200°C under vacuum. Calcium vapors formed in low yield under such thermodynamic conditions are transferred from the reactor and condensed in cool zones, thus shifting the equilibrium to allow formation of more calcium vapors. The reactions are as follows ... 

Calcium oxide is commercially obtained from limestone. The carbonate is roasted in a shaft or rotary khn at temperatures below 1,200°C untd aU CO2 is driven off. The compound is obtained as either technical, refractory or agricultural grade product. The commercial product usually contains 90 to 95% free CaO. The impurities are mostly calcium carbonate, magnesium carbonate, magnesium oxide, iron oxide and aluminum oxide. 

Refractory bricks composed of oxides of magnesium, chromium, aluminum and iron and trace amounts of silica and calcium oxide are used in roofs of open hearths, sidewalls of electric furnaces and vacuum apparatus and copper converters. Such refractories are made in an arc furnace by fusing mixtures of magnesite and chrome ore. 

Numerous methods for the synthesis of salicyl alcohol exist. These involve the reduction of salicylaldehyde or of salicylic acid and its derivatives. The alcohol can be prepared in almost theoretical yield by the reduction of salicylaldehyde with sodium amalgam, sodium borohydride, or lithium aluminum hydride by catalytic hydrogenation over platinum black or Raney nickel or by hydrogenation over platinum and ferrous chloride in alcohol. The electrolytic reduction of salicylaldehyde in sodium bicarbonate solution at a mercury cathode with carbon dioxide passed into the mixture also yields saligenin. It is formed by the electrolytic reduction at lead electrodes of salicylic acids in aqueous alcoholic solution or sodium salicylate in the presence of boric acid and sodium sulfate. Salicylamide in aqueous alcohol solution acidified with acetic acid is reduced to salicyl alcohol by sodium amalgam in 63% yield. Salicyl alcohol forms along with -hydroxybenzyl alcohol by the action of formaldehyde on phenol in the presence of sodium hydroxide or calcium oxide. High yields of salicyl alcohol from phenol and formaldehyde in the presence of a molar equivalent of ether additives have been reported (60). Phenyl metaborate prepared from phenol and boric acid yields salicyl alcohol after treatment with formaldehyde and hydrolysis (61). 

Commercial tert.-butyl alcohol dried over calcium oxide is suitable for this preparation. Aluminum isopropoxide or ethoxide 2 may be used in place of the aluminum /er/.-butoxide to remove traces of water. The grade of metal known as fast cutting rods has proved most satisfactory. The checkers used turnings made from aluminum cast from melted-down kitchen utensils. Aluminum ferf.-butoxide has also been prepared successfully in another laboratory from commercially pure aluminum (2S) and from rods of the alloy 17ST (communication from L. F. Fieser). The checkers were able to obtain considerably higher yields of the butoxide from pure aluminum than from a copper-bearing alloy. 

There are three fundamental stages in the process of manufacture of Portland cement, namely. (I) preparation of the raw mixture. (2) production of the clinker. (3) preparation of Ihe cement. Whether the process used is wet or dry. the raw materials are selected, analyzed, and mixed so dial, alter ireatmeni, Ihe product, or clinker, has a desired, narrowly specified composition A factory analysis of slurry, where the wet process is in use. is as follows calcium oxide 44%. aluminum oxide 3.5%. silicon oxide... 

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