석회질소

용도Calcium Cyanamide 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 ferrocyanides. manufacture of calcium cyanide, melamine, dicyandiamide.

일반 설명A colorless to gray, odorless solid. May cause illness from ingestion. May irritate the skin. If exposed to water or high temperatures, calcium cyanamide may generate toxic and flammable fumes. Used to make pesticides and in fertilizers.

생산 방법Calcium cyanamide was first produced commercially around 1900 as a fertilizer. The process of making calcium cyanamide involves three raw materials—coke, coal, and limestone— plus nitrogen. The limestone (calcium carbonate) is burned with coal to produce calcium oxide. The calcium oxide is then allowed to react with amorphous carbon in the furnace at 2000°C with the formation of calcium carbide (CaC2). Finely powdered calcium carbide is heated to 1000°C in an electric furnace into which pure nitrogen is passed. It is then removed and uncombined calcium carbide removed by leaching.

Calcium cyanamide is prepared from calcium carbide. The carbide powder is heated at about 1,000°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. CaC2 + N2 → CaCN2 + C (ΔHƒ°= –69.0 kcal/mol at 25°C)

정의calcium cyanamide: A colourlesssolid, CaCN2, which sublimes at1300°C. It is prepared by heating calciumdicarbide at 800°C in a streamof nitrogen:CaC2(s) + N2(g) → CaCN2(s) + C(s)The reaction has been used as amethod of fixing nitrogen in countriesin which cheap electricity isavailable to make the calcium dicarbide(the cyanamide process). Calciumcyanamide can be used as afertilizer because it reacts with waterto give ammonia and calcium carbonate:CaCN2(s) + 3H2O(l) → CaCO3(s) +2NH3(g)It is also used in the production ofmelamine, urea, and certain cyanidesalts.