Calciumoxid Chemische Eigenschaften,Einsatz,Produktion Methoden
ERSCHEINUNGSBILD
HYGROSKOPISCHES, WEISSES, KRISTALLINES PULVER.
CHEMISCHE GEFAHREN
Mittelstarke Base in wässriger Lösung. Reagiert mit Wasser und entwickelt ausreichend Hitze, um brennbares Material zu entzünden. Reagiert sehr heftig mit Säuren, Halogenen, Metallen.
ARBEITSPLATZGRENZWERTE
TLV: 2 mg/m?(als TWA) (ACGIH 2005).
MAK: IIb (nicht festgelegt, aber Informationen vorhanden); (DFG 2005).
AUFNAHMEWEGE
Aufnahme in den Körper durch Inhalation des Aerosols und durch Verschlucken.
INHALATIONSGEFAHREN
Verdampfung bei 20°C vernachlässigbar; eine gesundheitsschädliche Partikelkonzentration in der Luft kann jedoch beim Dispergieren schnell erreicht werden.
WIRKUNGEN BEI KURZZEITEXPOSITION
WIRKUNGEN BEI KURZZEITEXPOSITION: Die Substanz verätzt die Augen, die Haut und die Atemwege. Die Auswirkungen treten u.U. verzögert ein. ärztliche Beobachtung notwendig.
WIRKUNGEN NACH WIEDERHOLTER ODER LANGZEITEXPOSITION
Wiederholter oder andauernder Hautkontakt kann Dermatitis hervorrufen. Risiko der Lungenschädigung bei wiederholter oder längerer Exposition gegenüber Staubpartikeln. Die Substanz kann Geschwürbildung und Perforation der Nasenscheidewand verursachen.
LECKAGE
Verschüttetes Material in trockenen Behältern sammeln. Persönliche Schutzausrüstung: Atemschutzgerät, P2-Filter für schädliche Partikel.
R-Sätze Betriebsanweisung:
R34:Verursacht Verätzungen.
R41:Gefahr ernster Augenschäden.
S-Sätze Betriebsanweisung:
S26:Bei Berührung mit den Augen sofort gründlich mit Wasser abspülen und Arzt konsultieren.
S36/37/39:Bei der Arbeit geeignete Schutzkleidung,Schutzhandschuhe und Schutzbrille/Gesichtsschutz tragen.
S45:Bei Unfall oder Unwohlsein sofort Arzt zuziehen (wenn möglich, dieses Etikett vorzeigen).
S25:Berührung mit den Augen vermeiden.
S39:Schutzbrille/Gesichtsschutz tragen.
Aussehen Eigenschaften
CaO, Ätzkalk, gebrannter Kalk.
Gefahren für Mensch und Umwelt
Gefährliche Reakt. mit Säuren und
Schwefelwasserstoff. Substanz ist feuchtigkeitsempfindlich. Bei Zusatz von Wasser starke Wärmeentwicklung.
Verätzungen an Haut und Schleimhäuten. Nach Augenkontakt : Starke irreversible Verätzungen, Erblindungsgefahr.
Toxisch für Wasserorganismen. Schädigende Wirkg. durch Verschiebung des pH-Wertes. Neutralisation möglich. Schwach wassergefährdend.
Schutzmaßnahmen und Verhaltensregeln
Dicht verschlossen. Trocken. Bei Zimmertemp. (Empfohlen: +15?bis+ 25?C).
Beim Auftreten von Stäuben Partikelmaske tragen
Schutzbrille mit Seitenschutz und oberer Augenraumabdeckung
Neopren-Schutzhandschuhe als kurzzeitiger Spritz- und Staubschutz.
Verhalten im Gefahrfall
Festsubstanz mechanisch aufnehmen, Flüssigkeit und Lösung mit flüssigkeitsbindendem Material (Sand, Kieselgur, Säurebinder, Universalbinder, Sägemehl) aufnehmen. Anschließend neutralisieren und mit Wasser nachreinigen.
keine Einschränkung
Erste Hilfe
Nach Hautkontakt: Nach Berührung sofort mit Seife und viel Wasser abwaschen.
Nach Augenkontakt: Sofort mind. 15 Minuten bei gespreizten Lidern unter fließendem Wasser mit Augendusche ausspülen. Augenarzt konsultieren!
Nach Einatmen: Person sofort an die frische Luft bringen.
Nach Verschlucken: Nach Verschlucken: Zitronensaft, Essig oder in Milch eingequirlte rohe Eier, dann viel Wasser trinken lassen, Erbrechen vermeiden (Perforationsgefahr), sofort Arzt hinzuziehen.
Ersthelfer: siehe gesonderten Anschlag
Sachgerechte Entsorgung
Falls Recycling nicht möglich, darf die Substanz nicht mit Hausmüll entsorgt werden. Substanz darf nach sorgfältiger Neutralisation in das Abwasser gegeben werden. Auskunft: Hr. Riepl, Tel.: 8884711 oder Hr. Uhl, Tel.: 2015557.
Beschreibung
Calcium oxide (CaO, CAS Reg. No. 1305-78-8) is also known as lime, quick lime, burnt lime, or calx. Lime does not occur naturally since it reacts so readily with water (to form hydrated lime) and carbon dioxide (to form limestone). It is produced from calcium carbonate, limestone, or oyster shells by calcination at temperatures of 1,700-2,450℃.
Calcium Oxide is a solid with a very high affinity for water - it will react with water in the air, or in your skin or anywhere it can and form calcium hydroxide. This reaction is exothermic so it releases a lot of heat while it is reacting - there fore as well as being corrosive and causing significant skin irritation, calcium oxide's reaction with water can also cause burns. Calcium hydroxide is basically hydrated calcium oxide. It is alkali so can be corrosive. In solution it makes limewater.
CaO is not found pure in nature but rather is contained in various abundant minerals (i.e. calcite, aragonite, limestone, marble) but vary greatly in their purity (impurities usually include magnesia, iron, alumina, silica, sulfur). Of these iron and sulfur are most troublesome (i.e. where clarity is important in glass). Lime minerals vary in the degree of crystallization and cohesion of the crystalline mass and the homogeneity of the matrix.
Calcium oxide is the principle flux in medium and high temperature glazes, beginning its action (within the glaze) around 1100C. It must be used with care in high-fire bodies because its active fluxing action can produce a body that is too volatile (melting if slightly overfired).
Lime, or calcium oxide, is a principle ingredient in the production of Portland cement, the basis for most mortars and concrete. Hydrated or ‘slaked’ lime is the chemical calcium hydroxide. This chemical is also used in mortars. Both types of lime are strong bases and are also used in food production (calcium hydroxide is commonly used in making corn tortillas), petroleum refining and sewage treatment. In the household it is used by aquarium hobbyists to add bioavailable calcium to fish tanks. It is also found in hair relaxers.
Chemische Eigenschaften
Calcium oxide, CaO, occurs as white or
grayish-white lumps or granular powder. The presence of iron
gives it a yellowish or brownish tint.
Physikalische Eigenschaften
Calcium oxide is a white caustic crystalline alkali substance that goes by the common name lime. The term lime is used both generically for several calcium compounds and with adjectives to qualify different forms of lime. This entry equates lime, also called quicklime or burnt lime, with the compound calcium oxide. Hydrated lime, made by combining lime with water, is calcium hydroxide and is often referred to as slaked lime (Ca(OH)
2). Dolomite limes contain magnesium as well as calcium. Limestone is the compound calcium carbonate. The term lime comes from the Old English word l?m for a sticky substance and denotes lime’s traditional use to produce mortar. Calx was the Latin word for lime and was used to name the element calcium.
History
Calcium oxide dates from prehistoric times. It is produced by heating limestone to drive off carbon dioxide in a process called calcination: CaCO
3(s) CaO
(s) + CO
2(g). At temperatures of several hundred degrees Celsius, the reaction is reversible and calcium oxide will react with atmospheric carbon dioxide to produce calcium carbonate. Efficient calcium oxide production is favored at temperatures in excess of 1,000°C. In prehistoric times limestone was heated in open fires to produce lime. Over time, lined pits and kilns were used to produce lime. Brick lime kilns were extensively built starting in the 17th century and the technology to produce lime has remained relatively constant since then.
Verwenden
The major uses of lime are metallurgy, flue gas desulfurization, construction, mining, papermaking, and water treatment. About one third of calcium oxide production in the United States is used for metallurgical processes, principally in the iron and steel industry. Calcium oxide is used to remove impurities during the refining of iron ore. Calcium oxide combines with compounds such as silicates, phosphates, and sulfates contained in iron ores to form slag. Lime is also used for purification in other metal refining and to control pH in mining processes such as leaching and precipitation. The calcium oxide is also used in remediation of mine wastes to recover cyanides and to neutralize acid mine drainage.
Verwenden
In bricks, plaster, mortar, stucco and other building and construction materials; manufacture of steel, aluminum, magnesium, and flotation of non-ferrous ores; manufacture of glass, paper, Na2CO3 (Solvay process), Ca salts and many other industrial chemicals; dehairing hides; clarification of cane and beet sugar juices; in fungicides, insecticides, drilling fluids, lubricants; water and sewage treatment; in laboratory to absorb CO2 (the combination with NaOH is known as soda-lime, q.v.).
Verwenden
Calcium Oxide is a general food additive consisting of white granules
or powder of poor water solubility. it is obtained by heating limestone
(calcium carbonate) in a furnace. it is also termed lime or quicklime.
it is used as an anticaking agent, firming agent, and nutritive supple-
ment in applications such as grain products and soft candy.
Definition
ChEBI: A member of the class of calcium oxides of calcium and oxygen in a 1:1 ratio.
Vorbereitung Methode
Calcium oxide is commercially obtained from limestone. The carbonate is roasted in a shaft or rotary kiln at temperatures below 1,200°C until all CO
2 is driven off. The compound is obtained as either technical, refractory or agri cultural grade product. The commercial product usually contains 90 to 95% free CaO. The impurities are mostly calcium carbonate, magnesium carbon ate, magnesium oxide, iron oxide and aluminum oxide.
Aroma threshold values
Aroma at 1.0%: intense, high impacting fresh sweet juicy lime, citral with a distilled lime note, cool and
refreshing with green juicy nuances.
Taste threshold values
Taste characteristics at 10 ppm in 5% sugar and 0.1% CA; intense fresh tangy lime juice, citrus citral candy
lime character with notes of West Indian lime
Allgemeine Beschreibung
An odorless, white or gray-white solid in the form of hard lumps. A strong irritant to skin, eyes and mucous membranes. Used in insecticides and fertilizers.
Air & Water Reaktionen
Crumbles on exposure to moist air. Reacts with water to form corrosive calcium hydroxide, with evolution of much heat. Temperatures as high as 800° C have been reached with addition of water (moisture in air or soil). The heat of this reaction has caused ignition of neighboring quantities of sulfur, gunpowder, wood, and straw [Mellor 3: 673 1946-47].
Reaktivität anzeigen
A base and an oxidizing agent. Neutralizes acids with generation of heat. Nonflammable, but will support combustion by liberation of oxygen, especially in the presence of organic materials. Reacts very violently with liquid hydrofluoric acid [Mellor 2, Supp. 1:129 1956]. Reacts extremely violently with phosphorus pentaoxide when reaction is initiated by local heating [Mellor 8 Supp.3:406 1971].
Hazard
Evolves heat on exposure to water. Danger-
ous near organic materials. Upper respiratory tract
irritant.
Health Hazard
Causes burns on mucous membrane and skin. Inhalation of dust causes sneezing.
Brandgefahr
Non-combustible, substance itself does not burn but may decompose upon heating to produce corrosive and/or toxic fumes. Vapors may accumulate in confined areas (basement, tanks, hopper/tank cars etc.). Substance will react with water (some violently), releasing corrosive and/or toxic gases and runoff. Contact with metals may evolve flammable hydrogen gas. Containers may explode when heated or if contaminated with water.
Landwirtschaftliche Anwendung
Calcium oxide (CaO) is a white powder with a
neutralizing value or calcium carbonate equivalent
(CCE) of 179%, compared to 100% for calcium
carbonate (CaCO
3). For quick results, either calcium
oxide or calcium hydroxide [Ca(OH)
2] is used. Calcium
oxide is also known as lime, unslaked lime, burned lime
or quicklime. Roasting CaCO
3 in a furnace makes
calcium oxide. A complete mixing of calcium oxide with
soil is difficult because it cakes due to absorption of
water.
Landwirtschaftliche Anwendung
Lime is a white caustic alkaline substance. It consists of
calcium oxide which is obtained by heating limestone,
and has a high neutralizing value.
Industrielle Verwendung
Lime is the most widely used reagent in the mineral industry for flotation of sulfides and, in some cases, non-sulfide minerals. The word “lime” is a general term used to describe any kind of calcareous material or finely divided form of limestone and dolomite. In more strict chemical terms, lime is calcinated limestone known as calcium oxide (CaO), quicklime or unslaked lime.The slaked or hydrated lime Ca(OH)2 is the form of lime primarily used in mineral flotation. Production of high-calcium lime is based on calcination of limestone at a temperature of 1100–1300 °C in kilns.
CaCO3+heat--->CaO+CO2 For high-magnesium (dolomitic) limestone, the calcination reaction (at 1000–1200 °C) is CaCO3·MgCO3 (limestone) + heat--->CaOMgO (quicklime-2CO2)
Sicherheitsprofil
A caustic and irritating
material. See also CALCIUM
COMPOUNDS. A common air
contaminant. A powerful caustic to living
tissue. The powdered oxide may react
explosively with water. Mixtures with
ethanol may igmte if heated and thus can
cause an air-vapor explosion. Violent
reaction with (I3203 + CaCl2) interhalogens
(e.g., BF3, CIF3), F2, HF, P2O5 + heat, water.
Incandescent reaction with liquid HF.
Incompatible with phosphoms(V) oxide.
mögliche Exposition
Calcium oxide is used as a refractory
material; a binding agent in bricks; plaster, mortar, stucco,
and other building materials. A dehydrating agent, a flux in
steel manufacturing, and a labora
Versand/Shipping
UN1910 Calcium oxide, Hazard class: 8; Labels:
8-Corrosive material.
Inkompatibilitäten
The water solution is a medium strong
base. Reacts with water, forming calcium hydroxide and
sufficient heat to ignite nearby combustible materials.
Reacts violently with acids, halogens, metals.
Waste disposal
Pretreatment involves neutralization with hydrochloric acid to yield calcium chloride.
The calcium chloride formed is treated with soda ash to
yield the insoluble calcium carbonate. The remaining brine
solution may be discharged into sewers and waterways
Calciumoxid Upstream-Materialien And Downstream Produkte
Upstream-Materialien
Downstream Produkte
