කැල්සියම් කාබයිඩ්

Calcium carbide is a chemical compound with the chemical formula of Ca. The pure material is colorless, but most samples have a color ranging from black to grayish-white, depending on the grade. Its main use industrially is in the production of acetylene and .

කැල්සියම් කාබයිඩ්

Names
කැල්සියම් කාබයිඩ්
Identifiers
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	CHEBI:{{{value}}}
	100.000.772
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(EPA)	DTXSID4026399
Properties
Molecular formula	CaC2
	64.099 g/mol
Appearance	White powder to grey/black crystals
	2.22 g/cm^3
	2160 °C, 2433 K, 3920 °F
	2300 °C, 2573 K, 4172 °F
in water	decomposes
Structure
	Tetragonal
	D^174h, I4/mmm,
	6
Hazards
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).  Y   (verify)

Calcium carbide.

Production

Calcium carbide is produced industrially in an from a mixture of and at approximately 2000 °C. This method has not changed since its invention in 1888:

CaO + 3 C → CaC₂ + CO

The high temperature required for this reaction is not practically achievable by traditional combustion, so the reaction is performed in an electric arc furnace with graphite electrodes. The carbide product produced generally contains around 80% calcium carbide by weight. The carbide is crushed to produce small lumps that can range a few mm up to 50 mm. The impurities are concentrated in the finer fractions. The CaC₂ content of the product is assayed by measuring the amount of acetylene produced on hydrolysis. As an example, the British and German standards for the content of the coarser fractions are 295 L/kg and 300 L/kg respectively. Impurities present in the carbide include phosphide, which produces when hydrolysed.

This reaction was an important part of the in chemistry, and was made possible in the USA as a product of massive amounts of cheap liberated from before the turn of the 20th century.

The method for the production in an was discovered independently by and in 1888 and 1892.

Crystal structure

Pure calcium carbide is a colourless solid. The common crystalline form at room temperature is a distorted rock salt structure with the C₂²⁻ units lying parallel.

යෙදවුම්

ඇසිටිලින් නිපැයුම

The reaction of calcium carbide with water was discovered by in 1862.

CaC₂ + 2 H₂O → C₂H₂ + Ca(OH)₂

This reaction is the basis of the industrial manufacture of acetylene, and is the major industrial use of calcium carbide. In China, acetylene derived from calcium carbide remains a raw material for the chemical industry, in particular for the production of . Locally produced acetylene is more economical than using imported oil. Production of calcium carbide in China has been increasing. In 2005 output was 8.94 million tons, with the capacity to produce 17 million tons. In the USA, Europe and Japan consumption is generally declining. Production levels in the USA in 1990s were 236,000 tons per year.

කැල්සියම් cyanamide නිපැයුම

කැල්සියම් කාබයිඩ් reacts with nitrogen at high temperature to form කැල්සියම් cyanamide:

CaC₂ + N₂ → CaCN₂ + C

Calcium cyanamide is used as fertilizer. It is hydrolysed to , H₂NCN.

Steel නිපැයුම

කැල්සියම් කාබයිඩ් is used:

• in the of iron (pig iron, cast iron and steel)
• as a fuel in steelmaking to extend the scrap ratio to liquid iron, depending on economics.
• as a powerful at treatment facilities.

කාබයිඩ් ලාම්පු

මූලික ලිපිය:

Lit carbide lamp

Calcium carbide is used in , in which water drips on the carbide and the acetylene formed is ignited. These lamps were usable but dangerous in coal mines, where the presence of the flammable gas methane made them a serious hazard. The presence of flammable gases in coal mines led to the miner . However, carbide lamps were used extensively in slate, copper and tin mines, but most have now been replaced by electric lamps. Carbide lamps are still used for mining in some less wealthy countries, such as in the silver mines near Potosi, Bolivia. Carbide lamps are also still used by some and other underground areas, though they are increasingly being replaced in this use by lights. They were also used extensively as headlights in early automobiles, motorcycles and bicycles, although in this application they are also obsolete, having been replaced entirely by electric lamps.

Other uses

In the ripening of fruit, calcium carbide is used as source of acetylene gas, which is a ripening agent (similar to ).

It is still used in the for a traditional custom called Carbidschieten (Shooting Carbide). To create an explosion, carbide and water are put in a milk churn with a lid. Ignition is usually done with a torch. Some villages in the Netherlands fire multiple milk churns in a row as a New Year's Eve tradition. The tradition comes from an old religious practice intended to chase off spirits.

It is used in toy cannons (see ), as well as in .

Together with , calcium carbide is used in floating, self-igniting naval (see ).

Calcium carbide is also used in small carbide lamps called carbide candles, which are used for blackening rifle sights to reduce glare. These "candles" are used due to the sooty flame produced by acetylene.

බාහිර සබැඳුම්

• Calcium Carbide Manufacturing
• 2008 Material Safety Data Sheet 2012-11-19 at the Wayback Machine

References

1. Massalimov, I. A.; Kireeva, M. S.; Sangalov, Yu. A. (2002). Inorganic Materials. 38: 363. doi:10.1023/A:1015105922260. {{}}: Missing or empty |title= ()
2. Patnaik, Pradyot (2003). Handbook of Inorganic Chemical Compounds. McGraw-Hill. ISBN . සම්ප්‍රවේශය 2009-06-06.
3. Calcium Carbide, Bernhard Langhammer, Ullmann's Encyclopedia of Industrial Chemistry, Wiley Interscience. (Subscription required)
4. J. T. Morehead, G. de Chalmot (1896). "The Manufacture of Calcium Carbide". Journal of the American Chemical Society. 18 (4): 311–331. doi:10.1021/ja02090a001.
5. H. Moissan (1892). "Chimie Minérale.- Description d'un nouveau four électrique". Comptes rendus hebdomadaires des séances de l'Académie des sciences. 115: 1031.
7. Ya Dun (2006-01-23). "Troubles in the PVC industry". Hong Kong Trade Development Council.
8. . BusyTrade.com. 2007-05-16. 2007-02-11 දින මුල් පිටපත වෙතින් සංරක්ෂණය කරන ලදී. සම්ප්‍රවේශය 2010-08-28.
9. Jamie Lacson, Stefan Schlag and Goro Toki (2004). "Calcium Carbide". SRI Consulting. {{}}: Unknown parameter |month= ignored ()
10. "Caving equipment and culture (from [[Te Ara Encyclopedia of New Zealand]])". {{}}: URL–wikilink conflict ()
11. Clemmer, Gregg (1987). American Miners' Carbide Lamps: A Collectors Guide to American Carbide Mine Lighting. Westernlore Publications.
12. F. B. Abeles and H. E. Gahagan, III (1968). "Abscission: The Role of Ethylene, Ethylene Analogues, Carbon Dioxide, and Oxygen". 43 (8): 1255–1258. doi:10.1104/pp.43.8.1255. PMC 1087003. PMID 16656908.
13. "an explanation of Carbid Schieten". සම්ප්‍රවේශය 2009-06-06.