| Identification | Back Directory | [Name]
Calcium carbide | [CAS]
75-20-7 | [Synonyms]
carbide
ELECTROLITE
Acetylenogen
Calciumcarbid
carburo calcic
ethyne,calciuM
carburocalcico
Acetylenestones
CALCIUM CARBIDE
calciumdicarbide
carburedecalcium
CALCIUM ACETYLIDE
ethyne,calciumderiv
CALCIUMCARBIDE,LUMP
calciumcarbide(cac2)
Calciumcarbide,75-82%
CALCIUM CARBIDE, 97+%
TechnicalCalciumCarbide
carburedecalcium(french)
calciumacetylide(ca(c2))
Calcium Carbide, 10-40 Mesh
Calcium Carbide, Anhydrous
CALCIUM CARBIDE, GRANULATED, 0.3-1 MM
Calciumcarbidemetallurggradegreylumpsmm
Calcium carbide, metallurg.grade, grey lumps, 9-40 mm
Calcium carbide, pieces, typically <10mm thick, tech., ~80%
Calcium carbide granulated, technical, >=75% (gas-volumetric)
CalciuM carbide pieces, thickness <10 MM , typically, technical grade, ~80% | [EINECS(EC#)]
200-848-3 | [Molecular Formula]
C2Ca | [MDL Number]
MFCD00010905 | [MOL File]
75-20-7.mol | [Molecular Weight]
64.1 |
| Chemical Properties | Back Directory | [Appearance]
grey or black solid with a garlic-like odour | [Melting point ]
447°C | [Boiling point ]
2300°C | [density ]
2.22 g/mL at 25 °C(lit.)
| [storage temp. ]
water-free area | [solubility ]
reacts with H2O | [form ]
pieces
| [color ]
Gray-black | [Specific Gravity]
2.22 | [Stability:]
Stability Reacts violently with water liberating highly flammable gas (acetylene). Do not use water if this material is involved in a fire. Incompatible with moisture, water, strong oxidizing agents, alcohols, hydrogen chloride, magnesium. | [Water Solubility ]
hydrolyses | [Sensitive ]
Moisture Sensitive | [Merck ]
14,1656 | [BRN ]
3909011 | [Dielectric constant]
5.8 - 7.0（0.0℃） | [Exposure limits]
ACGIH: TWA 2 mg/m3
OSHA: TWA 5 mg/m3
NIOSH: IDLH 25 mg/m3; TWA 2 mg/m3 | [InChIKey]
UIXRSLJINYRGFQ-UHFFFAOYSA-N | [EPA Substance Registry System]
Calcium carbide (Ca(C2))(75-20-7) |
| Safety Data | Back Directory | [Hazard Codes ]
F | [Risk Statements ]
15-41-37/38 | [Safety Statements ]
8-43-43A-39-26 | [RIDADR ]
UN 1402 4.3/PG 2
| [WGK Germany ]
1
| [F ]
10-21 | [TSCA ]
Yes | [HazardClass ]
4.3 | [PackingGroup ]
II | [HS Code ]
28491000 | [Safety Profile]
Reaction on contact
with moisture forms explosive acetylene gas.
Flammable on contact with moisture, acid
or acid fumes; evolves heat or flammable
vapors. Moderate explosion hazard.
Incandescent reaction with Cl2 (245℃), Brz
(350℃), IS (305℃), HCl gas + heat, PbF2,
Mg + heat. Incompatible with Se, (KOH +
Ch), AgNO3, Na2O2, SnCl2, S, water.
Mixtures with iron(IⅡ) chloride, iron(IⅡ)
oxide, tin(Ⅱ) chloride are easily ignited and
burn fiercely. Vigorous reaction with
methanol after an induction period.
Addttion to silver nitrate solutions
precipitates the dangerously explosive silver
acetylide. Copper salt solutions behave
similarly. See also CALCIUM
HYDROXIDE and ACETYLENE. | [Hazardous Substances Data]
75-20-7(Hazardous Substances Data) |
| Raw materials And Preparation Products | Back Directory | [Raw materials]
Calcium carbonate-->Calcium oxide-->CARBON MONOXIDE-->Carbon Black-->CALCIUM CARBONATE-->METALLURGICAL COKE-->Coke (coal)-->Electrode paste | [Preparation Products]
Sodium hypochlorite-->Ethyl vinyl ether-->1,3-Butadiene-->Dichloroethane-->Carbon Black-->Trichloroethylene-->Polyvinyl chloride-->Acetylene-->Calcium cyanamide-->2-Butyne-1,4-diol-->Propargyl alcohol-->Cement dust-->2-Methyl-2-butanol-->Tetrapotassium hexacyanoferrate trihydrate-->Polychloroprene-->Sulfadiazine-->Difluoroethane-->VINYL CHLORIDE-->2-Butene-1,4-diol-->1,1,2,2-Tetrabromoethane-->2-Butene-1,4-diol-->1,1,2,2-TETRABROMOETHANE |
| Hazard Information | Back Directory | [General Description]
Grayish-black irregular lump solid. Used to make acetylene and in steel manufacture. | [Air & Water Reactions]
Reacts rapidly with water to generate the flammable gas acetylene and the base calcium hydroxide. Enough heat may be generated to ignite the gas [Jones, G.W. BM Report Invest. 3755 1944]. | [Reactivity Profile]
Calcium carbide is a reducing agent. May react vigorously with oxidizing materials. The powdered mixture of the acetylide and iron oxide and iron chloride burns violently upon ignition, producing molten iron. Calcium carbide incandesces with chlorine, bromine, or iodine at 245, 350, or 305°C., respectively, [Mellor, 1946, Vol. 5, 862]. The carbide burns incandescently when mixed and heated with lead difluoride, magnesium, hydrogen chloride, and tin (II) chloride, [Mellor, 1946, 1940, 1946, and 1941], respectively. Interaction of Calcium carbide with methanol to give calcium methoxide is vigorous , but subject to an induction period of variable length. Once reaction starts, evolution of acetylene gas is very rapid, unpublished observations [Bretherick 1995]. Mixing Calcium carbide with silver nitrate solutions forms silver acetylide, a highly sensitive explosive. Copper salt solutions would behave similarly, [Photogr. Sci. Eng., 1966, 10, 334]. The mixture of Calcium carbide and sodium peroxide is explosive, as is Calcium carbide and perchloryl fluoride as gases at 100-300°C. | [Health Hazard]
Eye and skin irritation | [Fire Hazard]
Behavior in Fire: If wet by water, highly flammable acetylene gas is formed. | [Hazard]
Forms flammable and explosive gas and
corrosive solid with moisture.
| [Chemical Properties]
grey or black solid with a garlic-like odour | [Physical properties]
Grayish-black orthorhombic crystal; density 2.22 g/cm3; melts at 2,200°C; reacts with water. | [Preparation]
Calcium carbide (CaC2) is manufactured by heating a lime and carbon mixture to 2000 to 2100°C (3632 to 3812°F) in an electric arc furnace. At those temperatures, the lime is reduced by carbon to calcium carbide and carbon monoxide (CO), according to the following reaction: CaO + 3C → CaC2 + CO
Lime for the reaction is usually made by calcining limestone in a kiln at the plant site. The sources of carbon for the reaction are petroleum coke, metallurgical coke, and anthracite coal. Because impurities in the furnace charge remain in the calcium carbide product, the lime should contain no more than 0.5 percent each of magnesium oxide, aluminum oxide, and iron oxide, and 0.004 percent phosphorus. Also, the coke charge should be low in ash and sulfur. Analyses indicate that 0.2 to 1.0 percent ash and 5 to 6 percent sulfur are typical in petroleum coke. About 991 kilograms (kg) (2,185 pounds [lb]) of lime, 683 kg (1,506 lb) of coke, and 17 to 20 kg (37 to 44 lb) of electrode paste are required to produce 1 megagram (Mg) (2,205 lb) of calcium carbide. | [Reactions]
Calcium carbide is grayish-black solid, reacts with water yielding acetylene gas and calcium hydroxide, formed at electric furnace temperature from calcium oxide and carbon. | [Potential Exposure]
Those involved in the manufacture andhandling of carbide and the generation of acetylene. | [First aid]
If this chemical gets into the eyes, remove anycontact lenses at once and irrigate immediately for at least15 min, occasionally lifting upper and lower lids. Seekmedical attention immediately. If this chemical contacts theskin, remove contaminated clothing and wash immediatelywith soap and water. Seek medical attention immediately. Ifthis chemical has been inhaled, remove from exposure,begin rescue breathing (using universal precautions, including resuscitation mask) if breathing has stopped and CPR ifheart action has stopped. Transfer promptly to a medicalfacility. When this chemical has been swallowed, get medical attention. Give large quantities of water and inducevomiting. Do not make an unconscious person vomit.Medical observation is recommended for 24-48 h afterbreathing overexposure, as pulmonary edema may bedelayed. As first aid for pulmonary edema, a doctor orauthorized paramedic may consider administering a corticosteroid spray. | [storage]
Color Code—Red Stripe: Flammability Hazard:Do not store in the same area as other flammable materials.Color Code—Green: General storage may be used. Prior toworking with calcium carbide you should be trained on itsproper handling and storage. Store in tightly closed containers in a cool, well-ventilated area away from moisture andwithout sprinkler protection and avoid contact with incompatible materials. Use only nonsparking tools and equipment especially when opening and closing containers ofcalcium carbide. Metal containers involving the transfer ofthis chemical should be grounded and bonded. Use explosion-proof electrical equipment in the carbide-handlingarea. Sources of ignition, such as smoking and open flames,are prohibited where this chemical is used, handled, orstored in a manner that could create a potential fireor explosion hazard. | [Shipping]
Calcium carbide requires a “DANGEROUSWHEN WET” label. It falls in Hazard Class 4.3 andPacking Groups I or II. | [Incompatibilities]
Water contact or moist air forms calciumhydroxide and explosive acetylene gas with risk of fire andexplosion. Keep away from acids, oxidizers, hydrogenchloride, methanol, copper salt solutions, lead fluoride,magnesium, selenium, silver nitrate, iron trichloride, tindichloride, sodium peroxide, stannous chloride, sulfur. |
| Questions And Answer | Back Directory | [Description]
Calcium carbide (molecule formula: CaC2), is a kind of important chemical raw materials produced from the chemical processing of limestone. In 1892, H. Maysan (French) and H. Wilson (United state) simultaneously developed a calcium carbide production approach based on furnace Reduction. The United State had successfully achieved industrial production in 1895. The property of calcium carbide is related to its purity. Its industrial product is mostly the mixture of calcium carbide and calcium oxide, and also contains trace amounts of sulfur, phosphorus, nitrogen and other impurities. With the increasing content of impurities, it color exhibits gray, brown to black. The melting point and electrical conductivity both decrease with the decrease of the purity. The purity of its industrial product is usually 80% with m.p. being 1800~2000 °C. At room temperature, it does not react with air, but it can have oxidation reaction at above 350 ℃, and have reaction with nitrogen at 600~700 ℃ to generate calcium cyanamide. Calcium carbide, when coming across with water or steam, generates acetylene and release a large amount of heating. CaC2 + 2H2O─ → C2H2 + Ca (OH) 2 + 125185.32J, 1kg of pure calcium carbide can produce 366 L of acetylene 366l (15 ℃, 0.1MPa). Thereby, for its storage: calcium carbide should be strictly kept away from water. It is usually packed in a sealed iron container, and sometimes stored in a dry warehouse being filled with nitrogen if necessary.
| [Uses]
Industry
Applications
Benefit
Chemical manufacture
Production of acetylene gas
Raw materials,CaC2 + 2 H2O → C2H2 + Ca(OH)2
Production of calcium cyanamide
Raw materials, CaC2 + N2 → CaCN2 + C
Production of various acetylene derivatives
Source of acetylene gas
Production of calcium hydroxide
Raw materials, CaC2 + 2 H2O → C2H2 + Ca(OH)2
Steel production
The desulfurisation of iron (pig iron, cast iron and steel)
Desulfurization agent
As a fuel in steelmaking
Extend the scrap ratio to liquid iron
Ladle treatment facilities
A powerful deoxidizer
Mining, automobiles and street lighting
Carbide lamps
React with water to make acetylene gas, which can burn to glow
Fruit
Artificial ripening fruit
Source of acetylene gas
Signal flares
Floating, self-igniting naval signal flares
Used together with calcium phosphide
Cylinder gas
Metal fabrication and construction
Source of acetylene gas
Experiment teaching
Teaching reagent
Experiment reagent
| [Reaction with water]
Calcium carbide will immediately have reaction upon coming across with water, generating acetylene and calcium hydroxide, which is the approach of industrial preparation of acetylene (carbide method), the reaction equation is:
CaC2 + 2H2O = C2H2 + Ca (OH) 2.
Since the impurity of calcium carbide, the generated acetylene gas is usually mixed with a small amount of hydrogen sulfide, phosphine gas and other contaminants, so there is a bad smell. Calcium carbide is produced from the lime and coke in an electric furnace at a high temperature of 3000 ℃:
3C + CaO = CaC2 + CO.
Upon the laboratory preparation of acetylene, owing to the reaction between calcium carbide and water is very fierce, we can apply saturated brine to substitute water so that a pure and smooth airflow of acetylene can be obtained. Calcium carbide won’t have reaction with sodium chloride.
| [Production method]
Electric furnace reduction method is the only method for industrial production of calcium carbide at present. Put calcium oxide and coke for reduction reaction at 2000~2200 ℃: CaO + 3C─ → CaC2 + CO-480644.64J, the resulting molten calcium carbide flow into the receiver tank from the bottom of the reactor, and we obtain the final product after cooling. Calcium carbide production belongs to high temperature operation with relative large amount dust being produced and consuming a large amount of electrical energy. In 1980s, the production of per ton of calcium carbide consumes industrial power of about 10~11GJ. In order to reduce the power consumption, people mostly apply large-scale and closed calcium carbide furnace to reduce heat loss and also do good to the recycling of carbon monoxide. |
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