Abstract

Cyanamide has been commercially available, as calcium salt, since the beginning of the twentieth century. A commercial process for manufacturing a pure grade of cyanamide was introduced in 1964. Cyanamide was widely used as a nitrogen fertilizer and later as a raw material for dicyandiamide and melamine.

The use of cyanamide as a fertilizer has been replaced by ammonia and urea. Melamine is now made by a petrochemical process using natural gas. Cyanamide is still used in the manufacture of dicyandiamide and calcium cyanide. Cyanamide-based chemicals have also been used in special applications for defoliants, fungicides, herbicides, and as a weed killer. In pure form, cyanamides are used in the synthesis of many complex chemicals.

Calcium cyanamide is produced by both batch oven and continuous kiln processes. This article deals with the chemistry, manufacture, specifications, health and safety factors (toxicity and environment), and use of cyanamide homologues: cyanamide, dicyandiamide, and melamine.