CHEMICAL SUBSTANCE DATASHEET
CHEMICAL SUBSTANCE IDENTIFICATION |
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Chemical name |
Calcium oxide |
Synonyms |
Lime, Quicklime, Burnt lime, Calcia, Calcium monoxide, Calxyl, Hexocalex, Hexocalex 6-9, Heavy calcium oxide, etc. [1] |
IUPAC name |
Calcium oxide or oxocalcium |
CAS No |
1305-78-8 [2] |
REACH registration number |
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EC No |
215-138-9 [3] |
Molecular formula |
CaO |
Substance group/chemical family |
inorganic [3] |
Appearance Physical state Odour Form Colour |
solid [4] odourless [5] cubric crystals, granulated powder or hygroscopic lumps [5] white, greyish-white, greyish-yellow, brownish-yellow or colorless [5] |
USES AND HANDLING ISSUES |
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Relevant identified uses |
Used in construction applications e.g. brick, mortar, stucco production and ground consolidation. [7] Also used in many other sectors of the industry: bauxite processing, kraft paper pulp production, treatment of sewage and trade waste, treatment of stack gases, water purification and softening, manufacture of glass, paper, drilling fluids, lubricants, chlorinated lime, sodium carbonate (Solvay process), calcium slats, etc. In the industry usually appears as dehydrating agent, absorber, and buffer. [7] In the food industry, calcium oxide is utilized in clarification of cane and beet sugar juices and poultry feeding. Also can find as nutrient or dietary supplement food additive. [8] In metallurgy, principally used as a flux in steel production but also appears in the manufacture of aluminium, magnesium and non-ferrous ores. [5] In some states of the USA it is registered as a fungicide, insecticide ingredient. [7] |
Handling considerations |
Avoid breathing vapours or dusts. Avoid bodily contact with the material. If contact with the material anticipated, protective clothing and gloves, appropriate eye protection and any type of respirator prescribed. Eyewash fountains should be provided in areas where there is any possibility that workers could be exposed to the substance. Facilities for quickly drenching the body should be provided within the immediate work area where there is a possibility of exposure. [12] The worker should wash daily at the end of each work shift, and prior to eating, drinking, smoking, etc. Work clothing that becomes wet or significantly contaminated should be removed and replaced. [12] Dust sources should be enclosed. Enclosures should be fitted with exhaust ventilation. Air contaminated with lime dust should be passed through cyclones or bag filters before release into general atmosphere. In case of hot lime dust, cyclones and scrubbers should be employed. Settled lime dust inside premises should be collected by industrial vacuum cleaners and manual collection should be prohibited. Ventilation in vicinity of furnaces should be designed to extract dust and gases. [12] |
PHYSICO-CHEMICAL PROPERTIES |
|
Molecular weight |
56,077 g/mol [5] |
Bulk density/Specific gravity |
3,34 g/cm3 [5] |
pH |
12,8 (saturated solution in water) [5] |
EC |
1∙10-8S/cm on 777°C [17] |
Melting point |
2613°C [4] |
Boiling point |
2850°C [4] |
Flash point |
Not flammable [10] |
Flammability |
Not flammable but may produce high heat when contact with water. [10] |
Vapour density |
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Vapour pressure |
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Solubility in water |
Soluble: 1,19 g/L at 20°C and 0,57 g/L at 100°C. [6] |
Solubility in organic solvents |
Soluble in acids, glycerol, sugar solution but insoluble in alcohol. [7] |
Hydrolysis |
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Ionicity in water |
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Surface tension |
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Dispersion properties |
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Stability and reactivity |
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Chemical stability |
Crumbles on exposure to moist air. Absorbs CO2 and H2O from air and becomes air-slaked. [5] |
Reactivity hazards |
Has violent reaction with water or moist air which may release toxic, corrosive or flammable gases. Reaction with water may generate high heat (as high as 800°C) which will increase the concentration of fumes in the air. [9] The solution in water is a medium strong base. [4] Fire will produce irritating, corrosive and toxic gases. Runoff from fire control or dilution water may be corrosive, toxic and cause pollution. [9] Contact with metals may evolve flammable hydrogen gas. [9] Even at low temperature calcium oxide reacts with fluorine and chlorine trifluoride, evolving high heat, flames and light. [11] Reacts extremely violently with halogens (e.g. BF3, ClF3, HF, P2O5 and F2). [11] |
Corrosivity |
corrosive [5] |
Polimerization |
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Incompatibility with various substances |
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Special remarks on reactivity |
Becomes incandescent when heated to near its melting point. [8] The reaction of calcium oxide and boron trifluoride forms a fused mass after warming. [11] |
Physical, chemical and biological coefficients |
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Koc |
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Kow |
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pKa |
12,8 [5] |
Henry-constant |
Determining a Kd-value for calcium oxide is not relevant, since this molecule reacts with water to release calcium ions and hydroxyl ions. [3] |
ENVIRONMENTAL FATE AND BEHAVIOUR |
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Artificial pollution sources |
Commercial production from calcination of limestone. Properly stored limestone contains 90-95% free calcium oxide and calcium carbonate, magnesium, iron, aluminium oxides as impurities. [5] |
General terrestrial fate |
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General aquatic fate |
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General atmospheric fate |
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General persistence and degradability |
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Abiotic degradation and metabolites |
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Biodegradation and metabolites |
Biotic degradation is not relevant for inorganic substances [3] |
Bioconcentration |
This endpoint is considered not to be relevant for calcium oxide. [3]
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Volatilization |
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Photolysis |
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Hydrolysis |
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Soil adsorption and mobility |
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ENVIRONMENTAL CONCENTRATIONS |
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Measured data |
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ECOTOXICOLOGICAL INFORMATION |
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General adverse effects on ecosystem |
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Acute toxicity (LC50, EC50) |
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Aquatic systems
Terrestrial systems |
In aqueous suspension calcium oxide reacts basic and has toxic effect on fish. [10] Freshwater microorganisms: 3 hours mortality, LC50= 300,4 mg CaO/L. [4] Branchiura sowerbyi (tubificid worm): 96 hours mortality, LC50=83,0 mg CaO/L. [16] Cyclops viridis (copepod plankton): 96 hours mortality, LC50=27,8 mg CaO/L. [16] Oncorhynchus mykiss (freshwater fish): 96 hours mortality: LC50= 50,6 mg CaO/L. [4] Gasterosteus aculeatus Linnaeus (marine water fish): 96 hours mortality: LC50= 457 mg CaO/L. [4] |
Chronic toxicity (NOEC, LOEC) |
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Aquatic systems
Terrestrial systems |
Freshwater algae: 72 hours mortality, NOEC= 48 mg CaO/L. [4] Terrestrial plants: 21days, NOEC = 1 080 mg/kg soil dw (Both the read-across substance calcium dihydroxide and calcium carbonate gave similar 21-day NOEC values in OECD TG 208 studies of 1080 and 1000 mg/kg soil dw, respectively. Therefore, it may be concluded that grades of calcium oxide containing up to 35% calcium carbonate will have similar toxicity to plants. [3]) Soil macroorganisms (Eisenia fetida): Long term (14 days) mortality, NOEC = 2 000 mg/kg soil dw [3] Soil microorganisms: dehydrogenase activity, NOEC = 4 000 mg/kg soil dw [3] |
HUMAN HEALTH EFFECTS and PROTECTION |
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Routes of human exposures |
Occupational exposure of calcium oxide may occur through inhalation of fine dust and dermal contact with the compound at workplaces where calcium oxide is produced or used. [15] |
General effects |
Inhalation, ingestion or contact (skin, eyes) with vapours, dusts or substance may cause severe injury, burns or death. [13] |
Endocrine disruption |
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Mutagenicity |
Calcium oxide is considered to be non-mutagenic in a Salmonella typhimurium and Escherichia coli reverse mutation assay. [4] |
Carcinogenicity |
Neither calcium, calcium dihydroxide nor calcium carbonate are carcinogenic. Classification for carcinogenicity is not warranted. [3] |
Reprotoxicity |
Calcium, therefore also calcium oxide, does not pose any hazard for reproduction and/or developmental toxicity. Classification for toxicity to reproduction is not warranted. [3] |
Teratogenicity |
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Skin, eye and respiratory irritations
Metabolism: absorption, distribution & excretion |
May produce irritation, dry skin, redness, burning sensation and contact dermatitis when contact with the moist skin is repeated or extended. [13] Small sized particles and alkalinity of calcium oxide is highly irritating to mucous membranes, eyes and upper tract of respiratory system. There is a risk of serious damage (e.g. inflammation of respiratory passages, ulceration and perforation of nasal septum and pneumonia) as a result of local liberation of heat and dehydration of tissues. [13] Ingestion may cause abdominal pain, abdominal cramps, vomiting and diarrhoea. [14] |
Exposure limits |
Immediately dangerous to life or health: 25 mg/m3. [12] |
Drinking water MAC |
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Other information |
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Animal toxicity data |
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Acute toxicity (LD50) |
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Chronic toxicity (NOEL, LOEL) |
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ENVIRONMENTAL STANDARDS AND REGULATIONS |
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REACH/CLP |
Danger! According to the classification provided by companies to ECHA in REACH registrations this substance causes serious eye damage, causes skin irritation and may cause respiratory irritation. H315: causes skin irritation. H318: causes serious eye damage. H335: may cause respiratory irritation. Additionally, the classification provided by companies to ECHA in CLP notifications identifies that this substance causes severe skin burns and eye damage and is harmful if swallowed. H315: causes skin irritation. H318: causes serious eye damage. H335: may cause respiratory irritation. H314: Causes severe skin burns and eye damage. H302: Harmful if swallowed. H319: Causes serious eye irritation. |
EINECS regulation |
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OSHA regulations etc. |
Permissible Exposure Limit (PEL): 8 hours-time weighted average (TWA): 5 mg/m3. [13] Recommended Exposure Limit (REL): 10 hours-time weighted average: 2 mg/m3. [12] Threshold Limit Values (TLV): 8 hours-time weighted average (TWA): 2 mg/m3. [13] Excursion Limit Recommendation (ELR): excursions in worker exposure levels may exceed 3 times the TLV-TWA for no more than a total of 30 minutes during a work day, and under no circumstances should they exceed 5 times the TLV-TWA, provided that the TLV-TWA is not exceeded. [13] |
OTHER INFORMATION, SPECIAL REMARKS |
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Other standards, regulations and guidelines: |
GHS05: corrosion. GSH07: exclamation mark. R37: irritation to respiratory system. R38_ irritating to skin. R41: risk of serious damage to eyes. S2: keep out of the reach of children. S25: avoid eye contact. S26: in case of contact with eyes, rinse immediately and seek medical advice. S37: wear suitable gloves. S39: wear eye/ face protection. [3] |
CREATED, LAST UPDATE |
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8th of April, 2018 |
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29th of May, 2018 |
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REFERENCES |
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[1] PubChem (Open Chemistry Database) https://pubchem.ncbi.nlm.nih.gov/compound/Lime#section=InChI-Key [2] eCHEM (The Global Portal to Information on Chemical Substances) https://www.echemportal.org/echemportal/substancesearch/substancesearch_execute.action [3] ECHA (European Chemicals Agency) [4] INCHEM (Chemical Safety Information from Intergovernmental Organizations) http://www.inchem.org/documents/icsc/icsc/eics0409.htm [5] TOXNET (Toxicology Data Network) [6] Osol, A. (ed.). Remington's Pharmaceutical Sciences. 16th ed. Easton, Pennsylvania: Mack Publishing Co., 1980., p. 1267; through TOXNET [7] O'Neil, M.J. (ed.). The Merck Index - An Encyclopedia of Chemicals, Drugs, and Biologicals. Cambridge, UK: Royal Society of Chemistry, 2013., p. 294; through TOXNET [8] Lewis, R.J. Sr.; Hawley's Condensed Chemical Dictionary 15th Edition. John Wiley & Sons, Inc. New York, NY 2007., p. 21; through TOXNET [9] U.S. Department of Transportation. 2012 Emergency Response Guidebook. Washington, D.C. 2012; through TOXNET [10] European Chemicals Bureau; IUCLID Dataset, Calcium Oxide (1305-78-8). Available from, as of February 7, 2014; through TOXNET [11] National Fire Protection Association; Fire Protection Guide to Hazardous Materials. 14TH Edition, Quincy, MA 2010, p. 491-43; through TOXNET [12] NIOSH. NIOSH Pocket Guide to Chemical Hazards. Department of Health & Human Services, Centers for Disease Control & Prevention. National Institute for Occupational Safety & Health. DHHS (NIOSH) Publication No. 2010-168 (2010); through TOXNET [13] American Conference of Governmental Industrial Hygienists. Threshold Limit Values for Chemical Substances and Physical Agents and Biological Exposure Indices. ACGIH, Cincinnati, OH 2014, p. 17; through TOXNET [14] [International Program on Chemical Safety/Commission of the European Union; International Chemical Safety Card on Calcium Oxide (1305-78-8). Available from, as of 02.11.2014; through TOXNET [15] US EPA; Inventory Update Reporting (IUR). Non-confidential 2006 IUR Records by Chemical, including Manufacturing, Processing and Use Information. Washington, DC: U.S. Environmental Protection Agency. Available from, as of Jan 13, 2014; through TOXNET [16] Das BK, Das N; Chemosphere 61 (2): 186-91 (2005); through TOXNET [17] IOP Science http://iopscience.iop.org/article/10.1088/0508-3443/17/2/303/meta |