calcium oxide

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calcium oxide,

chemical compound, CaO, a colorless, cubic crystalline or white amorphous substance. It is also called lime, quicklime, or caustic lime, but commercial lime often contains impurities, e.g., silica, iron, alumina, and magnesia. It is prepared by heating calcium carbonatecalcium carbonate,
CaCO3, white chemical compound that is the most common nonsiliceous mineral. It occurs in two crystal forms: calcite, which is hexagonal, and aragonite, which is rhombohedral.
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 (e.g., limestonelimestone,
sedimentary rock wholly or in large part composed of calcium carbonate. It is ordinarily white but may be colored by impurities, iron oxide making it brown, yellow, or red and carbon making it blue, black, or gray. The texture varies from coarse to fine.
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) in a special lime kiln to about 500°C; to 600°C;, decomposing it into the oxide and carbon dioxide. Calcium oxide is widely used in industry, e.g., in making porcelain and glass; in purifying sugar; in preparing bleaching powderbleaching powder,
white or nearly white powder that is usually a mixture of calcium chloride hypochlorite, CaCl(OCl); calcium hypochlorite, Ca(OCl)2; and calcium chloride, CaCl2.
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, calcium carbide, and calcium cyanamide; in water softeners; and in mortars and cements. In agriculture it is used for treating acidic soils (limingliming
, application to the soil of calcium in various forms, generally as ground limestone, but also as marl, chalk, shells, or hydrated lime. Lime benefits soil by neutralizing acidity, improving texture, and increasing the activity of soil microorganisms.
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). It is incandescent when heated to high temperatures; the Drummond light, or limelight, provides a brilliant white light by heating a cylinder of lime with the flame of an oxyhydrogen torch. Calcium oxide is a basic anhydride, reacting with water to form calcium hydroxidecalcium hydroxide,
Ca(OH)2, colorless crystal or white powder. It is prepared by reacting calcium oxide (lime) with water, a process called slaking, and is also known as hydrated lime or slaked lime. When heated above 580°C; it dehydrates, forming the oxide.
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; during the reaction (slaking) much heat is given off and the solid nearly doubles its volume.

Calcium Oxide


(also quicklime), CaO, a compound of calcium and oxygen; colorless crystals with a density of 3.4 g/cm3 and a melting point of 2585°C. The industrial product is a white porous substance. Calcium oxide reacts vigorously with water, liberating a considerable amount of heat and forming calcium hydroxide: CaO + H2O = Ca(OH)2 (slaking process). Calcium oxide is obtained by the calcination of limestone or chalk. It is widely used in construction, the chemical industry, metallurgy, agriculture, and water purification.

calcium oxide

[′kal·se·əm ′äk‚sīd]
(inorganic chemistry)
CaO A caustic white solid sparingly soluble in water; the commercial form is prepared by roasting calcium carbonate limestone in kilns until all the carbon dioxide is driven off; used as a refractory, in pulp and paper manufacture, and as a flux in manufacture of steel. Also known as burnt lime; calx; caustic lime.


A white or grayish-white caustic substance, calcium oxide, usually obtained by heating limestone or marble at a high temperature; used chiefly in plasters, mortars, and cements. In the past, in many areas along the seacoast where limestone was scarce, seashells were heated to obtain lime. See also hydrated lime, hydraulic lime, mortar, shell lime, slaked lime.

calcium oxide

a white crystalline base used in the production of calcium hydroxide and bleaching powder and in the manufacture of glass, paper, and steel. Formula: CaO
References in periodicals archive ?
Even with the modest decrease observed in the dry matter and neutral detergent fiber digestibility coefficients and in the total digestible nutrient content, the intake of dry matter and neutral detergent fiber increased by approximately 20% and justify the use of calcium oxide in the chemical treatment of sugar cane destined to be used to feed lambs.
PAM plus aluminum sulfate and PAM plus calcium oxide reduced total and fecal coliform bacteria and fecal strep by about 99 percent.
CaO from eggshell waste is expected to replace other commercial calcium oxide which is more expensive and high cost of production.
While calcium oxide is a good choice (it does not form a prodegradant complex), it is not as active as zinc oxide.
Concentration of sulfur dioxide in flue gas is directly related to the content of combustible sulfur (organic + + pyretic) and behavior of calcium oxide at combustion of oil shale.
Chemical residue on the inside of the round-bottomed jars appears to be calcium oxide, a substance known to form during the salt-making process.
The sealant contains calcium oxide to keep products like pharmaceuticals dry.
Iron and steel operations have resorted to tough materials such as zirconia oxide, or aluminum oxide filters compounded with zirconia oxide, calcium oxide, yttrium oxide, mullite, spinels and other ceramics for improved thermal shock capabilities.
In addition to alum, the research team tested mixtures of sodium aluminate, calcium oxide (quicklime), calcium hydroxide (slaked lime), calcitic and dolomitic limestone, gypsum, ferrous and ferric chloride, and ferrous and ferric sulfate.
Heat is generated inside the container through the reaction of water and calcium oxide (more commonly known as crushed limestone.
Tenders are invited for supply of 200 units advanced desi magur seed and other accessories among the selected beneficiaries of 28 blocks of the district each unit contains 1200 nos advanced desi magur seed size 3 inches lime calcium oxide good quality 25 kg and andaluminium