||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
||The desulfurisation of iron (pig iron, cast iron and steel)
|As a fuel in steelmaking
||Extend the scrap ratio to liquid iron
|Ladle treatment facilities
||A powerful deoxidizer
|Mining, automobiles and street lighting
||React with water to make acetylene gas, which can burn to glow
||Artificial ripening fruit
||Source of acetylene gas
||Floating, self-igniting naval signal flares
||Used together with calcium phosphide
||Metal fabrication and construction
||Source of acetylene gas
Grayish-black irregular lump solid. Used to make acetylene and in steel manufacture.
Electric furnace reduction method is the only method for the production of calcium carbide in the industry at present. This approach has achieved industrial production in early 1895 (US). The production process demands high-temperature operation with yielding a large amount of dusts and large power consumption. The technology improvements can improve the operating conditions, reduce the heat loss and improve the recovery efficiency of carbon monoxide. People mostly apply closed and large of calcium carbide furnace. Crash the coke and lime, mixed evenly according to the proportion and add into closed calcium carbide furnace, give electricity for heating and perform reduced reaction at 2000-2200 ℃, generating molten calcium carbide, and flowing into the electric furnace from inside furnace, cool, crush and pack. Kg/ton of coke (84% of fixed carbon) 550 limestone (92% of CaO) 840 electric electrode paste, 3200 (kWh/ton).
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].
Eye and skin irritation
grey or black solid with a garlic-like odour
Behavior in Fire: If wet by water, highly flammable acetylene gas is formed.
used as desulfurizer and dehydrant of steel and for cutting and welding metals.?in organic synthesis industry, Acetylene obtanied from calcium carbide is raw material to make ethylene, chloroprene rubber, calcium cyanamide, acetic acd, acetaldehydr, ethylacetate, cyanide acetate, dicyandiamide, acetone, octanol, trichloride ethylene etc
Generating acetylene gas for lighting purposes (1 kg of carbide yields ~300 liters acetylene); as reducing agent, e.g., for direct reduction of copper sulfide to metallic copper; signal fires for marine service; manufacture of calcium, iron, alloys, lampblack, cyanamide; welding and cutting metals.
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.
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.
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.
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.