Calcium cyanamide process

Calcium cyanamid process, for ammonia synthesis, 11 114, 115 Calcium cyanide, 8 194-197 Calcium cyanide diammoniate, 8 195 Calcium dichromate, molecular formula, properties, and uses, 6 561t 5-Calcium disilicate monosulfate, phase in Portland cement clinker, 5 472t 5-Calcium disilicate monocarbonate, phase in Portland cement clinker, 5 472t Calcium disilicide, 4 530 8-Calcium disodium trialuminate, phase in Portland cement clinker, 5 472t Calcium doping, 23 842-844 Calcium P-alumina, 2 406t Calcium ethylenediaminetetraacetate, 7 596t... 

A technical exploitation of these experiments appeared unattractive, until 1909. Other methods of the chemical fixation of nitrogen, particularly the electric arc process for the formation of nitrous oxides (18) and the calcium cyanamide process (19) appeared far superior at that time. 

At about the same time the calcium cyanamide process was perfected. Calcium carbide, produced by reaction of lime with coke in an electric furnace, was converted to calcium cyanamide (CaCN2) by reaction with pure nitrogen extracted from the air. The product could be used directly as a fertilizer, or it could be hydrolyzed to form ammonia. 

Atmospheric nitrogen also can be fixed by the calcium cyanamide process, which is based on the fact that metallic carbides, particularly calcium carbide, readily react with nitrogen to form the metal cyanamide. Fairly pure nitrogen is reacted with calcium carbide to form the cyanamide ... 

In the commonly used Welland process, calcium cyanamide, made from calcium carbonate, is converted to cyanamide by reaction with carbon dioxide and water. Dicyandiamide is fused with ammonium nitrate to form guanidine nitrate. Dehydration with 96% sulfuric acid gives nitroguanidine which is precipitated by dilution. In the aqueous fusion process, calcium cyanamide is fused with ammonium nitrate ia the presence of some water. The calcium nitrate produced is removed by precipitation with ammonium carbonate or carbon dioxide. The filtrate contains the guanidine nitrate that is recovered by vacuum evaporation and converted to nitroguanidine. Both operations can be mn on a continuous basis (see Cyanamides). In the Marquerol and Loriette process, nitroguanidine is obtained directly ia about 90% yield from dicyandiamide by reaction with sulfuric acid to form guanidine sulfate followed by direct nitration with nitric acid (169—172). 

At about the same time that the Birkeland-Eyde process was developed, the Frank-Caro cyanamide process was commercialized (14). In this process limestone is heated to produce lime, which then reacts with carbon in a highly energy-demanding reaction to give calcium carbide. Reaction with N2 gives calcium cyanamide [150-62-7] which hydrolyzes to ammonia and calcium carbonate (see Cyanamides). 

The calcium cyanamide feed is weU mixed with the recycled slurry and filtrate ia a feed vessel. The calcium cyanamide is added at a rate to maintain a pH of 6.0—6.5 ia the cooling tank. The carbonation step can be conducted ia a turbiae absorber with a residence time of 1—2 min. After the carbonation step, the slurry is held at 30—40°C to complete the formation of calcium carbonate, after which the slurry is cooled and filtered. AH equipment for the process is preferably of stainless steel. The resulting solution is used directiy for conversion to dicyandiamide. 

The product obtained is white calcium cyanamide whereas the product obtained from limestone and coal contains carbonaceous (graphite) impurities. None of these processes has been commercially exploited. 

First industrial process involving atmospheric N2 — the Frank-Caro process for calcium cyanamide. 

M. Blais J.P. Picard, Effect of Various Physical Properties of Lime On The Purity of White Calcium Cyanamide Made By the Picatinny Process (U) , PATR 2457 (1957) 22) Anon,... 

Like the Haber process for the synthesis of ammonia, this reaction represents a way of converting elemental nitrogen into a compound (nitrogen fixation). Moreover, calcium cyanamide reacts with steam at high temperature to yield ammonia,... 

Frank-Caro Also called the Cyanamide process. An early process for fixing atmospheric nitrogen. Lime and carbon were heated to produce calcium carbide this was reacted with nitrogen to give calcium cyanamide, which was hydrolyzed with steam to yield ammonia and calcium carbonate. Developed by A. Frank and N. Caro from 1895 at Dynamit, Germany, and used in Germany, Norway, and Italy until it was replaced by the Haber-Bosch process after World War I. 

Polzeniusz-Krauss A process for making calcium cyanamide from calcium carbide by heating it in a nitrogen atmosphere in a chaimel kiln ... 

In the Prank Caro process, invented in 1895 - 7 and known as the "calcium cyanamide method, a carbide, such as Ca carbide absorbs nitrogen to form cyanamide(fertilizer), which by a further treatment may be transformed either into cyanide or into ammonia, Thi s process was used in Europe, USA and Canada (Refs 38 71). In the Serpek process introduced in France and not adopted in the USA, nitrogen was "fixed as Al nitride and this gave ammonia when treated with steam(Refs 38 and 71). In the Bagnulo process, invented in Italy, ammonia and other N-contg substances... 

Cyanide. Sodium cyanide. [CAS 143-33-9]. NaCN. white solid, soluble, very poisonous, formed (1) by reaction of sodamide and carbon at high temperature, (2) by reaction of calcium cyanamide and sodium chloride at high temperature, reacts in dilute solution in air with gold or silver to form soluble sodium gold or silver cyanide, and used for this purpose in the cyanide process for recovery of gold. The perceniage of available cyanide is greater than in potassium cyanide previously used. Used as a source of cyanide, and for hydrocyanic acid. 

Picard V.I.Siele, "Mechanism of Formation of White Calcium Cyanamide by the Picatinny Process , PATR 2405 (1957) (Conf) 16)J.P. Picard et al, "Laboratory Pilot Plant Investigation of Picatinny Process for Producing White Calcium Cyanamide , PATR 2452 (1957) (Conf) 17)V.I.Siele et al, "Suitability of White Calcium Cyanamide for the Preparation of Guanidine Nitrate , PATR 2455 (1957) (Conf) 18)M.Blais J.P.Picard, "Effect of Various Physical Properties of Lime on the Purity of White Calcium Cyanmide Made by the Picatinny Process , PATR 2457 (1857) (Conf) 19)S. 

The cyanamide process has made cyanamide and its derivatives more easily available for commercial synthesis. Coke and limestone are heated together in the electric furnace for the production of calcium carbide. This substance, along with a small amount of calcium chloride which acts as a catalyst, is then heated at 800-1000° in a stream of nitrogen gas. 

Cyanamide process. Although this process employs relatively inexpensive raw materials, it cannot compete with the Haber process under normal conditions. Formation of ammonia by the cyanamide process is based on the reaction between calcium cyanamide and steam ... 

One of the chief disadvantages involved in this process is the large quantity of energy that must be employed in the production of calcium carbide and in its conversion to calcium cyanamide. 

Calcium Cyanamide (H2N-CN) is used as a fertilizer, herbicide, insecticide, a steel-making additive and an ore processing material. It can also be used to make thiourea, guanidine and ferrocyanides142. SKW Chemicals in Germany (now part of Degussa) claims to be the world leader in production of cyanamide and cyanamide-based chemical intermediates. 

Nitric oxide, both from the arc process and the high-temperature oxidation of ammonia (the Ostvvald process) is used to make nitric acid. Calcium cyanamide is of use both as a nitrogen fertilizer and as a source of ammonia, to which is converted on hydrolysis with steam ... 

Calcium cyanamide, which is used as a fertilizer, herbicide, insecticide, a steelmaking additive, and an ore processing material. It can also be used to make... 

Summary 5-Aminotetrazole is prepared by reacting hydrazine monohydrate with hydrochloric acid, and calcium cyanamide solution. Afterwards, hydrochloric acid and sodium hydroxide are added, and then the mixture is heated. Afterwards, the mixture is cooled, and upon cooling, the 5-aminotetrazole precipitates. It is then collected by vacuum filtration. Commercial Industrial note For related, or similar information, see Application No. 392,308, February 22, 1995, by Nippon Carbide Kogyo Kabushiki Kaisha, Tokyo, JP, to Masahiro Murotani, Toyama, JP, Hajime Mura, Uozu, JP, Makoto Takeda, Takaoka, JP, and Hiroshi Shibafuchi, Uozu, JP. Part or parts of this laboratory process may be protected by international, and/or commercial/industrial processes. Before using this process to legally manufacture the mentioned compound, with intent to sell, consult any protected commercial or industrial processes related to, similar to, or additional to, the process discussed in this procedure. This process may be used to legally prepare the mentioned compound for laboratory, educational, or research purposes. 

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