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32-627: The pure material is colorless, while pieces of technical-grade calcium carbide are grey or brown and consist of about 80–85% of CaC 2 (the rest is CaO ( calcium oxide ), Ca 3 P 2 ( calcium phosphide ), CaS ( calcium sulfide ), Ca 3 N 2 ( 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. Applications of calcium carbide include manufacture of acetylene gas, generation of acetylene in carbide lamps , manufacture of chemicals for fertilizer, and steelmaking. Calcium carbide

64-540: A breakthrough in the provision of ammonia from atmospheric nitrogen and in 1901 recommended calcium cyanamide as a nitrogen fertilizer. Between 1908 and 1919, five calcium cyanamide plants with a total capacity of 500,000 tonnes per year were set up in Germany, and one in Switzerland. It was at the time the cheapest nitrogen fertilizer with additional efficacy against weeds and plant pests, and had great advantages over

96-439: A multifunctional nitrogen fertilizer for niche applications. Other reasons for its loss of popularity were its dirty-black color, dusty appearance and irritating properties, as well as its inhibition of an alcohol-degrading enzyme which causes temporary accumulation of acetaldehyde in the body leading to dizziness, nausea, and alcohol flush reaction when alcohol is consumed around the time of bodily exposure. Calcium cyanamide

128-404: A new process for producing cyanides for cyanide leaching of gold , Frank and Caro discovered the ability of alkaline earth carbides to absorb atmospheric nitrogen at high temperatures. Fritz Rothe, a colleague of Frank and Caro, succeeded in 1898 in overcoming problems with the use of calcium carbide and clarified that at around 1,100 °C not calcium cyanide but calcium cyanamide is formed in

160-492: A result of massive amounts of inexpensive hydroelectric power produced at Niagara Falls before the turn of the 20th century. The electric arc furnace method was discovered in 1892 by T. L. Willson , and independently in the same year by H. Moissan . In Jajce , Bosnia and Herzegovina , the Austrian industrialist Josef Kranz and his "Bosnische-Elektrizitäts AG" company, whose successor later became "Elektro-Bosna" , opened

192-430: Is a distorted rock-salt structure with the C 2 units lying parallel. There are three different polymorphs which appear at room temperature: the tetragonal structure and two different monoclinic structures. The reaction of calcium carbide with water, producing acetylene and calcium hydroxide , was discovered by Friedrich Wöhler in 1862. This reaction was the basis of the industrial manufacture of acetylene , and

224-405: Is conducted in slurries. For this reason, most commercial calcium cyanamide is sold as an aqueous solution. Thiourea can be produced by the reaction of hydrogen sulfide with calcium cyanamide in the presence of carbon dioxide. Calcium cyanamide is also used as a wire-fed alloy in steelmaking to introduce nitrogen into the steel. The substance can cause alcohol intolerance , before or after

256-468: Is in agriculture as a fertilizer. In contact with water, it hydrolyses into hydrogen cyanamide which decomposes and liberates ammonia : It was used to produce sodium cyanide by fusing with sodium carbonate : Sodium cyanide is used in cyanide process in gold mining. It can also be used in the preparation of calcium cyanide and melamine . Through hydrolysis in the presence of carbon dioxide , calcium cyanamide produces cyanamide: The conversion

288-591: 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. 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

320-445: Is prepared from calcium carbide . The carbide powder is heated at about 1000 °C in an electric furnace into which nitrogen is passed for several hours. The product is cooled to ambient temperatures and any unreacted carbide is leached out cautiously with water. It crystallizes in hexagonal crystal system with space group R3m and lattice constants a = 3.67 Å, c = 14.85 Å. The main use of calcium cyanamide

352-444: Is produced industrially in an electric arc furnace from a mixture of lime and coke at approximately 2,200 °C (3,990 °F). This is an endothermic reaction requiring 110 kilocalories (460 kJ) per mole and high temperatures to drive off the carbon monoxide. This method has not changed since its invention in 1892: The high temperature required for this reaction is not practically achievable by traditional combustion, so

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384-418: Is sometimes used as source of acetylene, which like ethylene gas, is a ripening agent . 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 . These impurities can be removed by passing the acetylene gas through acidified copper sulfate solution, but, in developing countries, this precaution

416-706: Is suitable for use in educational settings, but is not acceptable for food or drug use. Purified grade is not precisely defined, and it is not suitable for drug or food usage. Technical grade is suitable for industrial applications, but is not acceptable for food or drug use. References [ edit ] ^ "The Seven Most Common Grades for Chemicals and Reagents" . ^ "Demystifying Material Grades for Your Laboratory | GoldBio" . ^ "About ACS Reagents" . ACS Publications . American Chemical Society . Retrieved 2 August 2018 . ^ "The Importance of Reagent Purity Grades | Teknova" . www.teknova.com . Archived from

448-401: Is the inorganic compound with the formula CaCN 2 . It is the calcium salt of the cyanamide ( CN 2 ) anion. This chemical is used as fertilizer and is commercially known as nitrolime . It also has herbicidal activity and in the 1950s was marketed as cyanamid . It was first synthesized in 1898 by Adolph Frank and Nikodem Caro ( Frank–Caro process ). In their search for

480-420: 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

512-540: Is the measurement of the amount of impurities found in a sample . Several grades of purity are used by the scientific, pharmaceutical, and industrial communities. Some of the commonly used grades of purity include: ACS grade is the highest level of purity, and meets the standards set by the American Chemical Society (ACS). The official descriptions of the ACS levels of purity is documented in

544-463: Is used as fertilizer. It is hydrolysed to cyanamide , H 2 NCN. Calcium carbide is used: 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

576-442: 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. Calcium carbide is sold commercially as a mole repellent. When it comes into contact with water, the gas produced drives moles away. Chemical purity From Misplaced Pages,

608-621: The Reagent Chemicals publication, issued by the ACS. It is suitable for food and laboratory uses. Reagent grade is almost as stringent as the ACS grade. USP grade meets the purity levels set by the United States Pharmacopeia (USP). USP grade is equivalent to the ACS grade for many drugs. NF grade is a purity grade set by the National Formulary (NF). NF grade is equivalent to

640-788: 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, 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. Calcium carbide

672-576: The ACS grade for many drugs. British Pharmacopoeia : Meets or exceeds requirements set by the British Pharmacopoeia (BP). Can be used for food, drug, and medical purposes, and also for most laboratory purposes. Japanese Pharmacopeia : Meets or exceeds requirements set by the Japanese Pharmacopoeia (JP). Can be used for food, drug, and medical purposes, and also for most laboratory purposes. Laboratory grade

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704-601: 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. This reaction was an important part of the Industrial Revolution in chemistry, and was made possible in the United States as

736-564: The discontinuous process control. Nevertheless, both processes (the Rothe–Frank–Caro process and the Polzeniusz–Krauss process) played a role in the first half of the 20th century. In the record year 1945, a total of approximately 1.5 million tonnes was produced worldwide using both processes. Frank and Caro also noted the formation of ammonia from calcium cyanamide. Albert Frank recognized the fundamental importance of this reaction as

768-482: The 💕 Measure of the amount of impurities in a chemical sample [REDACTED] The examples and perspective in this article deal primarily with American designations and do not represent a worldwide view of the subject . You may improve this article , discuss the issue on the talk page , or create a new article , as appropriate. ( January 2022 ) ( Learn how and when to remove this message ) In chemistry , chemical purity

800-603: The largest chemical factory for the production of calcium carbide at the time in Europe in 1899. 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 1899. Pure calcium carbide is a colourless solid. The common crystalline form at room temperature

832-430: The melting point of calcium cyanamide is only about 120°C lower than the boiling point of sodium chloride. In 1901, Ferdinand Eduard Polzeniusz patented a process that converts calcium carbide to calcium cyanamide in the presence of 10% calcium chloride at 700 °C. The advantage of this reaction temperature (lower by about 400 °C), however, must be weighed against the large amount of calcium chloride required and

864-528: The nitrogen fertilizers that were conventional at the time. However, the large-scale implementation of ammonia synthesis via the Haber process became a serious competitor to the very energy-intensive Frank–Caro process. As urea (formed via the Haber–Bosch process) was significantly more nitrogen-rich (46% nitrogen compared to ca. 20%), cheaper, and faster acting, the role of calcium cyanamide was gradually reduced to

896-625: The original on 2022-06-25 . Retrieved 2022-04-04 . Retrieved from " https://en.wikipedia.org/w/index.php?title=Chemical_purity&oldid=1244250855 " Categories : Materials Chemical tests Environmental chemistry Adulteration Harm reduction Hidden categories: Articles with short description Short description is different from Wikidata Articles with limited geographic scope from January 2022 United States-centric Calcium cyanamide Calcium cyanamide , also known as Calcium carbondiamide , Calcium cyan-2°-amide or Calcium cyanonitride

928-483: The original on 2022-06-25 . Retrieved 2022-04-04 . ^ "The Importance of Reagent Purity Grades | Teknova" . www.teknova.com . Archived from the original on 2022-06-25 . Retrieved 2022-04-04 . ^ "How to use the BP - British Pharmacopoeia" . www.pharmacopoeia.com . Retrieved 2022-04-04 . ^ "The Importance of Reagent Purity Grades | Teknova" . www.teknova.com . Archived from

960-664: The production of polyvinyl chloride . 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 United States, Europe, and Japan, consumption of calcium carbide is generally declining. Production levels in the US during the 1990s were 236,000 tons per year. Calcium carbide reacts with nitrogen at high temperature to form calcium cyanamide : Commonly known as nitrolime , calcium cyanamide

992-440: 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 CaC 2 content of the product is assayed by measuring the amount of acetylene produced on hydrolysis . As an example,

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1024-399: The reaction. In fact, the initial target product sodium cyanide can also be obtained from calcium cyanamide by melting it with sodium chloride in the presence of carbon: Frank and Caro developed this reaction for a large-scale, continuous production process. It was particularly challenging to implement because it requires precise control of high temperatures during the initial igniter step;

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