Calcium oxide ( formula : Ca O ), commonly known as quicklime or burnt lime , is a widely used chemical compound . It is a white, caustic , alkaline , crystalline solid at room temperature . The broadly used term lime connotes calcium-containing inorganic compounds , in which carbonates , oxides , and hydroxides of calcium, silicon , magnesium , aluminium , and iron predominate. By contrast, quicklime specifically applies to the single compound calcium oxide. Calcium oxide that survives processing without reacting in building products , such as cement , is called free lime .
21-881: (Redirected from Cão ) [REDACTED] Look up Cao or CAO in Wiktionary, the free dictionary. Cao or CAO may refer to: Mythology [ edit ] Cao (bull) , a legendary bull in Meitei mythology Companies or organizations [ edit ] Air China Cargo , ICAO airline designator CAO CA Oradea , Romanian football club CA Osasuna , Spanish football club Canadian Association of Orthodontists Central Allocation Office , cross border electricity transmission capacity auction office Central Applications Office , Irish organisation that oversees college applications Civil Aviation Office of Poland Iran Civil Aviation Organization Office of
42-400: A lime kiln . This is accomplished by heating the material to above 825 °C (1,517 °F), a process called calcination or lime-burning , to liberate a molecule of carbon dioxide (CO 2 ), leaving quicklime behind. This is also one of the few chemical reactions known in prehistoric times. The quicklime is not stable and, when cooled, will spontaneously react with CO 2 from
63-467: A 15th-century Portuguese explorer Joseph Cao (born 1967), United States politician Lady of Cao , a Moche mummy, Peru Longbing Cao (born 1969), data scientist Places [ edit ] Cao (state) , a Chinese vassal state of the Zhou Dynasty (1046 - 221 BCE) Cao County , Shandong, China Cao Wei , also called Wei, one of the regimes that competed for control of China during
84-406: A 15th-century Portuguese explorer Joseph Cao (born 1967), United States politician Lady of Cao , a Moche mummy, Peru Longbing Cao (born 1969), data scientist Places [ edit ] Cao (state) , a Chinese vassal state of the Zhou Dynasty (1046 - 221 BCE) Cao County , Shandong, China Cao Wei , also called Wei, one of the regimes that competed for control of China during
105-694: A company Chief analytics officer of a company Compliance Advisor/Ombudsman , an independent office that reviews complaints Names [ edit ] Cao (Chinese surname) (曹) Cao (Vietnamese surname) People [ edit ] Cao (footballer, born 1968) , Portuguese footballer Cao Cao (died 220), founder of Cao Wei, China Cao Hamburger (born 1962), Brazilian director, screenwriter and producer Cao Pi (c.187–226), emperor of Cao Wei, China Cao Yu (1910–1996), Chinese playwright Cao Yupeng (born 1990), Chinese snooker player Carlos Alberto Caó (1941–2018), Brazilian activist, lawyer, and politician Diogo Cão ,
126-694: A company Chief analytics officer of a company Compliance Advisor/Ombudsman , an independent office that reviews complaints Names [ edit ] Cao (Chinese surname) (曹) Cao (Vietnamese surname) People [ edit ] Cao (footballer, born 1968) , Portuguese footballer Cao Cao (died 220), founder of Cao Wei, China Cao Hamburger (born 1962), Brazilian director, screenwriter and producer Cao Pi (c.187–226), emperor of Cao Wei, China Cao Yu (1910–1996), Chinese playwright Cao Yupeng (born 1990), Chinese snooker player Carlos Alberto Caó (1941–2018), Brazilian activist, lawyer, and politician Diogo Cão ,
147-584: Is an alternative material in industrial plasters and mortars. Cement, cement kiln dust, fly ash, and lime kiln dust are potential substitutes for some construction uses of lime. Magnesium hydroxide is a substitute for lime in pH control, and magnesium oxide is a substitute for dolomitic lime as a flux in steelmaking. Because of vigorous reaction of quicklime with water, quicklime causes severe irritation when inhaled or placed in contact with moist skin or eyes. Inhalation may cause coughing, sneezing, and labored breathing. It may then evolve into burns with perforation of
168-857: Is different from Wikidata All article disambiguation pages All disambiguation pages Cao [REDACTED] Look up Cao or CAO in Wiktionary, the free dictionary. Cao or CAO may refer to: Mythology [ edit ] Cao (bull) , a legendary bull in Meitei mythology Companies or organizations [ edit ] Air China Cargo , ICAO airline designator CAO CA Oradea , Romanian football club CA Osasuna , Spanish football club Canadian Association of Orthodontists Central Allocation Office , cross border electricity transmission capacity auction office Central Applications Office , Irish organisation that oversees college applications Civil Aviation Office of Poland Iran Civil Aviation Organization Office of
189-475: Is different from Wikidata All article disambiguation pages All disambiguation pages Calcium oxide Quicklime is relatively inexpensive. Both it and the chemical derivative calcium hydroxide (of which quicklime is the base anhydride ) are important commodity chemicals. Calcium oxide is usually made by the thermal decomposition of materials, such as limestone or seashells , that contain calcium carbonate (CaCO 3 ; mineral calcite ) in
210-420: Is required per 1.0 t of quicklime. Quicklime has a high affinity for water and is a more efficient desiccant than silica gel . The reaction of quicklime with water is associated with an increase in volume by a factor of at least 2.5. Hydroxyapatite's free CaO content rises with increased calcination temperatures and longer times. It also pinpoints particular temperature cutoffs and durations that impact
231-768: The Chief Administrative Officer of the United States House of Representatives Compliance Advisor/Ombudsman , accountability arm of the World Bank Council for Adult Education, later Centre for Adult Education , in Victoria, Australia Job titles [ edit ] Chief Academic Officer of a University, often titled the Provost Chief accounting officer of a company Chief administrative officer of
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273-504: The ORiN robot interface Topics referred to by the same term [REDACTED] This disambiguation page lists articles associated with the title Cao . If an internal link led you here, you may wish to change the link to point directly to the intended article. Retrieved from " https://en.wikipedia.org/w/index.php?title=Cao&oldid=1210782376 " Category : Disambiguation pages Hidden categories: Short description
294-454: The ORiN robot interface Topics referred to by the same term [REDACTED] This disambiguation page lists articles associated with the title Cao . If an internal link led you here, you may wish to change the link to point directly to the intended article. Retrieved from " https://en.wikipedia.org/w/index.php?title=Cao&oldid=1210782376 " Category : Disambiguation pages Hidden categories: Short description
315-503: The Three Kingdoms period (220 - 280 CE) Other uses [ edit ] CaO, the chemical symbol for calcium oxide Cão! , an album by Portuguese band Ornatos Violeta CA Osasuna , a Spanish sport club a Child Arrangement Order under English family law Chlorophyllide-a oxygenase , an enzyme Cold air outbreak , an intense and/or prolonged cold weather wave of air Controller Access Object, as described in
336-439: The Three Kingdoms period (220 - 280 CE) Other uses [ edit ] CaO, the chemical symbol for calcium oxide Cão! , an album by Portuguese band Ornatos Violeta CA Osasuna , a Spanish sport club a Child Arrangement Order under English family law Chlorophyllide-a oxygenase , an enzyme Cold air outbreak , an intense and/or prolonged cold weather wave of air Controller Access Object, as described in
357-454: The air until, after enough time, it will be completely converted back to calcium carbonate unless slaked with water to set as lime plaster or lime mortar . Annual worldwide production of quicklime is around 283 million tonnes. China is by far the world's largest producer, with a total of around 170 million tonnes per year. The United States is the next largest, with around 20 million tonnes per year. Approximately 1.8 t of limestone
378-519: The crowds. Quicklime is also thought to have been a component of Greek fire . Upon contact with water, quicklime would increase its temperature above 150 °C (302 °F) and ignite the fuel. David Hume , in his History of England , recounts that early in the reign of Henry III , the English Navy destroyed an invading French fleet by blinding the enemy fleet with quicklime. Quicklime may have been used in medieval naval warfare – up to
399-427: The nasal septum, abdominal pain, nausea and vomiting. Although quicklime is not considered a fire hazard, its reaction with water can release enough heat to ignite combustible materials. Calcium oxide is also a separate mineral species (with the unit formula CaO), named 'Lime'. It has an isometric crystal system , and can form a solid solution series with monteponite . The crystal is brittle, pyrometamorphic, and
420-599: The production of CaO, offering information on how calcination parameters impact the composition of the material. In 80 BC, the Roman general Sertorius deployed choking clouds of caustic lime powder to defeat the Characitani of Hispania , who had taken refuge in inaccessible caves. A similar dust was used in China to quell an armed peasant revolt in 178 AD, when lime chariots equipped with bellows blew limestone powder into
441-402: The use of "lime-mortars" to throw it at the enemy ships. Limestone is a substitute for lime in many applications, which include agriculture, fluxing, and sulfur removal. Limestone, which contains less reactive material, is slower to react and may have other disadvantages compared with lime, depending on the application; however, limestone is considerably less expensive than lime. Calcined gypsum
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