How Does calcium carbide stone Work?

Cal­ci­um car­bide has great prac­ti­cal sig­nif­i­cance. It is also known as cal­ci­um acetylide.

Wanding contains other products and information you need, so please check it out.

The chem­i­cal char­ac­ter­is­tics of cal­ci­um car­bide

Cal­ci­um car­bide is not volatile and not sol­u­ble in any known sol­vent, and re­acts with wa­ter to yield acety­lene gas and cal­ci­um hy­drox­ide. Its den­si­ty is 2.22 g/cm³. Its melt­ing point is °C, and its boil­ing point is °C. Since the acety­lene that forms upon con­tact with wa­ter is flammable, the sub­stance is list­ed in haz­ard class 4.3.

Cal­ci­um acetylide was first ob­tained by Ger­man chemist Friedrich Wöh­ler in when he heat­ed an al­loy of zinc and cal­ci­um with coal. The sci­en­tist de­scribed the re­ac­tion of cal­ci­um car­bide with wa­ter. Cal­ci­um car­bide re­acts vig­or­ous­ly with even mere traces of ''O, re­leas­ing a large amount of heat. If there is an in­suf­fi­cient quan­ti­ty of wa­ter, the re­sult­ing acetylide spon­ta­neous­ly com­busts. Cal­ci­um acetylide re­acts vi­o­lent­ly with aque­ous so­lu­tions of al­ka­lis and di­lut­ed non-or­gan­ic acids. These re­ac­tions re­lease acetylide. With its strong re­duc­tive prop­er­ties, CaC' re­duces all met­al ox­ides to pure met­als or turns them into car­bides.

It is eas­i­er to ob­tain cal­ci­um car­bide from its ox­ide than from cal­ci­um it­self, as the ox­ide is re­duced at tem­per­a­tures above °C. The met­al and car­bon com­bine:

CaO + 3C ' CO' + CaC'

The re­ac­tion takes place in an elec­tric arc fur­nace, where a mix­ture of un­slaked lime and coke or an­thracite is heat­ed. The tech­ni­cal prod­uct is grey due to the pres­ence of free car­bon, cal­ci­um ox­ide, phos­phide, sul­fide, and oth­er chem­i­cal com­pounds. CaC' com­pris­es 80-85% of the prod­uct by mass.

Use of cal­ci­um car­bide

In the past, cal­ci­um car­bide was used in car­bide lamps, where it served as a source of acety­lene flame. Nowa­days these lamps are still used to pow­er light­hous­es and bea­cons, and also in cave ex­plo­ration. CaC' also serves as a raw ma­te­ri­al in the de­vel­op­ment of chem­i­cal tech­nolo­gies, most no­tably syn­thet­ic rub­ber. Cal­ci­um car­bide is also used to make vinyl chlo­ride, acety­lene black, acry­loni­trile, acetic acid, ace­tone, eth­yl­ene, styrene, and syn­thet­ic resins.

A sim­ple ex­per­i­ment can be used to demon­strate the re­ac­tion of cal­ci­um car­bide with wa­ter: pour wa­ter into a 1.5 L bot­tle, quick­ly add sev­er­al pieces of cal­ci­um car­bide, and close the bot­tle with a stop­per. As a re­sult of the en­su­ing re­ac­tion be­tween cal­ci­um car­bide and wa­ter, acety­lene col­lects in the bot­tle as pres­sure builds. As soon as the re­ac­tion stops, place a burn­ing piece of pa­per in the bot­tle ' this should trig­ger an ex­plo­sion ac­com­pa­nied by a fiery cloud. As the walls of the bot­tle can burst as a re­sult of the re­ac­tion, this ex­per­i­ment is dan­ger­ous, and should only be con­duct­ed with strict ob­ser­vance of safe­ty pre­cau­tions.

Warn­ing! Do not at­tempt these ex­per­i­ments with­out pro­fes­sion­al su­per­vi­sion! Look here for ex­per­i­ments with flame you can safe­ly do at home

To demon­strate the re­ac­tion of cal­ci­um car­bide with wa­ter, the ex­per­i­ment can be re­peat­ed in mod­i­fied form ' us­ing a six-liter bot­tle. In this case, the com­po­nents must be weighed with pre­ci­sion, be­cause the greater the ra­dius of the bot­tle, the less the con­tain­er can with­stand high pres­sure (as­sum­ing iden­ti­cal ma­te­ri­al and wall thick­ness). A bot­tle with a large ca­pac­i­ty has a large ra­dius, but its walls are ap­prox­i­mate­ly the same ' ac­cord­ing­ly, it is less re­sis­tant to pres­sure. To pre­vent it from ex­plod­ing, the amount of cal­ci­um car­bide must be cal­cu­lat­ed be­fore­hand. Cal­ci­um has a mo­lar mass of 40 g/mol, while car­bon's is 12 g/mol, so the mo­lar mass of cal­ci­um car­bide is around 64 g/mol. Ac­cord­ing­ly, 64 g of car­bide will yield 22.4 L of acety­lene. The vol­ume of the bot­tle is 6 L, and the pres­sure has risen by ap­prox­i­mate­ly 4 at­mos­pheres.

The bot­tle must with­stand five at­mos­pheres: to con­duct the ex­per­i­ment, we take around 64 g of cal­ci­um car­bide and about 0.5 L of wa­ter. Place a piece of car­bide in­side a small bag. Push the bag into the bot­tle, then quick­ly close the bot­tle with the stop­per. The re­ac­tion of cal­ci­um car­bide with wa­ter con­tin­ues for sev­er­al min­utes, the bot­tle swells up and the process is ac­com­pa­nied by loud bangs, but the bot­tle should with­stand this.

Chemical compound Calcium carbide Names Preferred IUPAC name Calcium acetylide Systematic IUPAC name Calcium ethynediide Other names

• Calcium percarbide
• Calcium carbide
• Calcium dicarbide

Identifiers

• 75-20-7 Y

3D model (JSmol) ChemSpider

•  Y

ECHA InfoCard 100.000.772 EC Number

• 200-848-3

PubChem CID UNII

• 846WNV4A5F Y

CompTox Dashboard (EPA)

• InChI=1S/C2.Ca/c1-2;/q-2;+2 YKey: UIXRSLJINYRGFQ-UHFFFAOYSA-N Y
• InChI=1/C2.Ca/c1-2;/q-2;+2Key: UIXRSLJINYRGFQ-UHFFFAOYAI

• [Ca+2].[C-]#[C-]

Properties CaC2 Molar mass 64.100 g·mol'1 Appearance White powder or colorless crystals, grey/brown/black crystals if impure Density 2.22 g/cm3 Melting point 2,160 °C (3,920 °F; 2,430 K) Boiling point 2,300 °C (4,170 °F; 2,570 K) Reacts to produce Acetylene Structure[1] Tetragonal (I phase)
Monoclinic (II phase)
Monoclinic (III phase) I4/mmm (I phase)
C2/c (II phase)
C2/m (III phase) 6 Thermochemistry Std molar
entropy (S'298) 70 J/(mol·K) Std enthalpy of
formation (ΔfH'298) '63 kJ/mol Hazards Occupational safety and health (OHS/OSH): Main hazards Reacts with water to release acetylene gas[2] GHS labelling: Danger H260 NFPA 704 (fire diamond) 305 °C (581 °F; 578 K) (acetylene) Related compounds Related compounds Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Y   (what is YN ?) Chemical compound

Calcium carbide, also known as calcium acetylide, is a chemical compound with the chemical formula of CaC2. Its main use industrially is in the production of acetylene and calcium cyanamide.[3]

The pure material is colorless, while pieces of technical-grade calcium carbide are grey or brown and consist of about 80'85% of CaC2 (the rest is CaO (calcium oxide), Ca3P2 (calcium phosphide), CaS (calcium sulfide), Ca3N2 (calcium nitride), SiC (silicon carbide), C (carbon), etc.). In the presence of trace moisture, technical-grade calcium carbide emits an unpleasant odor reminiscent of garlic.[4]

Applications of calcium carbide include manufacture of acetylene gas, generation of acetylene in carbide lamps, manufacture of chemicals for fertilizer, and steelmaking.

Production

[edit]

Calcium carbide is produced industrially in an electric arc furnace from a mixture of lime and coke at approximately 2,200 °C (3,990 °F).[5] This is an endothermic reaction requiring 110 kilocalories (460 kJ) per mole[6] and high temperatures to drive off the carbon monoxide. This method has not changed since its invention in :

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 from 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 (at 101 kPa pressure and 20 °C (68 °F) temperature). Impurities present in the carbide include calcium phosphide, which produces phosphine when hydrolysed.[7]

This reaction was an important part of the Industrial Revolution in chemistry, and was made possible in the United States as a result of massive amounts of inexpensive hydroelectric power produced at Niagara Falls before the turn of the 20th century.[8] The electric arc furnace method was discovered in by T. L. Willson, and independently in the same year by H. Moissan.[9][10][11] In Jajce, Bosnia and Herzegovina, the Austrian industrialist Josef Kranz and his "Bosnische-Elektrizitäts AG" company, whose successor later became "Elektro-Bosna", opened the largest chemical factory for the production of calcium carbide at the time in Europe in . A hydroelectric power station on the Pliva river with an installed capacity of 8 MW was constructed to supply electricity for the factory, the first power station of its kind in Southeast Europe, and became operational on 24 March .[12]

Contact us to discuss your requirements of calcium carbide stone. Our experienced sales team can help you identify the options that best suit your needs.

Additional reading:
How to Choose Glass Curtain Wall Container House?

Crystal structure

[edit]
How Can Agricultural Polyethylene Pipe Solve Your Irrigation Challenges Efficiently?
How is USRP N200 Revolutionizing Software Defined Radio?

Calcium carbide is a calcium salt of acetylene, consisting of calcium cations Ca2+ and acetylide anions 'C'C'. Pure calcium carbide is a colourless solid. The common crystalline form at room temperature is a distorted rock-salt structure with the C2'2 units lying parallel.[13] There are three different polymorphs which appear at room temperature: the tetragonal structure and two different monoclinic structures.[1]

Applications

[edit]

Production of acetylene

[edit]

The reaction of calcium carbide with water, producing acetylene and calcium hydroxide,[5] was discovered by Friedrich Wöhler in .

CaC2(s) + 2 H2O(l) ' C2H2(g) + Ca(OH)2(aq)

This reaction was the basis of the industrial manufacture of acetylene, and is the major industrial use of calcium carbide.

Today acetylene is mainly manufactured by the partial combustion of methane or appears as a side product in the ethylene stream from cracking of hydrocarbons. Approximately 400,000 tonnes are produced this way annually (see acetylene preparation).

In China, acetylene derived from calcium carbide remains a raw material for the chemical industry, in particular for the production of polyvinyl chloride. Locally produced acetylene is more economical than using imported oil.[14] Production of calcium carbide in China has been increasing. In output was 8.94 million tons, with the capacity to produce 17 million tons.[15]

In the United States, Europe, and Japan, consumption of calcium carbide is generally declining.[16] Production levels in the US during the s were 236,000 tons per year.[13]

Production of calcium cyanamide

[edit]

Calcium carbide reacts with nitrogen at high temperature to form calcium cyanamide:[5]

CaC2 + N2 ' CaCN2 + C

Commonly known as nitrolime, calcium cyanamide is used as fertilizer. It is hydrolysed to cyanamide, H2N'C'N.[5]

Steelmaking

[edit]

Calcium carbide is used:

• in the desulfurization of iron (pig iron, cast iron and steel)[7]
• as a fuel in steelmaking to extend the scrap ratio to liquid iron, depending on economics.
• as a powerful deoxidizer at ladle treatment facilities.

Carbide lamps

[edit] Main article: Carbide lamp

Calcium carbide is used in carbide lamps. Water dripping on carbide produces acetylene gas, which burns and produces light. While these lamps gave steadier and brighter light than candles, they were dangerous in coal mines, where flammable methane gas made them a serious hazard. The presence of flammable gases in coal mines led to miner safety lamps such as the Davy lamp, in which a wire gauze reduces the risk of methane ignition. Carbide lamps were still used extensively in slate, copper, and tin mines where methane is not a serious hazard. Most miners' lamps have now been replaced by electric lamps.

Carbide lamps are still used for mining in some less wealthy countries, for example in the silver mines near Potosí, Bolivia. Carbide lamps are also still used by some cavers exploring caves and other underground areas,[17] although they are increasingly being replaced in this use by LED lights.

Carbide lamps were also used extensively as headlamps in early automobiles, motorcycles and bicycles, but have been replaced entirely by electric lamps.[18]

Other uses

[edit]

Calcium carbide is sometimes used as source of acetylene, which like ethylene gas, is a ripening agent.[19] However, this is illegal in some countries as, in the production of acetylene from calcium carbide, contamination often leads to trace production of phosphine and arsine.[20][21] These impurities can be removed by passing the acetylene gas through acidified copper sulfate solution, but, in developing countries, this precaution is often neglected.

Calcium carbide is used in toy cannons such as the Big-Bang Cannon, as well as in bamboo cannons. In the Netherlands calcium carbide is used around new-year to shoot with milk churns.[22]

Calcium carbide, together with calcium phosphide, is used in floating, self-igniting naval signal flares, such as those produced by the Holmes' Marine Life Protection Association.

Calcium carbide is used to determine the moisture content of soil. When soil and calcium carbide are mixed in a closed pressure cylinder, the water content in soil reacts with calcium carbide to release acetylene whose pressure can be measured to determine the moisture content.[23][24]

Calcium carbide is sold commercially as a mole repellent.[25] When it comes into contact with water, the gas produced drives moles away.[26]

Want more information on Powdered Calcium Carbide? Feel free to contact us.

References

[edit]