For most of the 20th century it has been used as a fertilizer, and also as a cotton defoliant, herbicide, and soil insecticide. Its use as a fertilizer has diminished in recent years due to the introduction of other compounds, so that the chief industrial uses of calcium cyanamide today stem from the reactivity of the nitrile group. Calcium cyanamide can be dimerized to dicyandiamide, an intermediate for melamine, one of the basic ingredients in amino plastics and resins. Other products prepared from calcium cyanamide include urea, thiourea, and guanidine. Fusion of calcium cyanamide with sodium chloride produces calcium cyanide, which is required for ore processing and the production of ferrocyanides.
Calcium cyanamide is added to pig iron to impart nitrogen and to remove sulfur from steel.
A bioassay of formulated calcium cyanamide for possible carcinogenicity was conducted by administering the test chemical in feed to F344 rats and B6C3F 1 mice. Groups of 50 mice of each sex were administered the test chemical at one of two doses, either 500 or 2,000 ppm, for 100 weeks. Matched controls consisted of 20 untreated rats and 20 untreated mice of each sex. All surviving animals were killed at the end of administration of the test chemical. Mean body weights of the dosed rats and mice were only slightly lower than those of corresponding controls, except for the low-dose female mice, whose mean body weights were unaffected by the test chemical.