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

Collins Discovery Encyclopedia, 1st edition © HarperCollins Publishers 2005

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.

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.

The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.

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.

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References in periodicals archive

4, hydration of calcium oxide CaO is going partially according to reaction CaO + [Ca.sup.2+] + [H.sub.2]O = 2CaO[H.sup.+].

Research of calcium oxide hydration in calcium nitrate solutions

Among the applied alleviating additives, bentonite and calcium oxide (in smaller degree) proved the most effective as regards the number of those bacteria in samples contaminated with petroleum-derived substances, especially with petrol.

Influence of petroleum-derived substances on number of oligotrophic and copiotrophic bacteria in soil

Explains Entry, "We already knew, from work others had done, that chemicals like aluminum sulfate and calcium oxide can slow the loss of phosphorus.

PAM protects against pollutants and pathogens

The alkalinity of cement is due to calcium oxide. In reported cases of cement burn,[1-3] most patients were unaware of the hazards of prolonged contact with cement.

Cement burn

He had invented a mixture containing naphtha, plus potassium nitrate and calcium oxide, perhaps (we don't know the exact recipe), which not only burned but would continue to burn on water even more fiercely.

Greek fire

The scientists achieved a 5-log reduction of bacteria at 25 C in 40 minutes using a concentration of 0.01% calcium oxide; in 30 minutes using 0.02% calcium oxide; in 20 minutes using 0.03% calcium oxide; and in 12 minutes using 0.04% calcium oxide.

Scallop shells a source of antibacterial materials against planktonic E. coli O157:H7 strain

Besides, thermodynamically speaking, it can be assumed that this type of oxide has been formed during the reaction between an acidic compound (manganese oxide) and an alkaline oxide (calcium oxide).

Scientists Study Thermodynamic Stability of Layered Manganese Oxide in Oxidation Reaction

Then there is a completely different approach which, instead of employing solvents, uses calcium or carbonate looping technology--essentially taking limestone and reducing it to calcium oxide. For capture purposes, the C[O.sub.2] absorbs reactively on the calcium oxide, being converted to calcium carbonate.

Still on the back burner: Britain leads the world in the science behind carbon capture. But where is the political will to turn this into workable technology that could create jobs as well as combating climate change?

The reactor concentrates solar energy using mirrors, in a chamber containing calcium oxide. At 400 degree Celsius, heat causes the calcium oxide to react with CO2 to form calcium carbonate.

Soon, 'green' cars that could run on CO2 and sunlight

There are other viable metal oxides for activating cure systems, for example, calcium oxide. While calcium oxide is a good choice (it does not form a prodegradant complex), it is not as active as zinc oxide.

Activation systems for improved aging in epichlorohydrin terpolymer compounds

The oil shale ash melting characteristics ([t.sub.A]--the initial deformation temperature; [t.sub.B]--the softening temperature and [t.sub.C]--the fluid temperature) depending on the calcium oxide content of ash have been investigated.

Oil shale combustion technology