| 摘要 |
Zinc cyanamide is produced by dispersing calcium cyanamide in water, reacting this suspension with sulphuric acid or carbon dioxide to form a solution of free cyanamide, and reacting this solution with a slurry of zinc hydrate. The formation of the cyanamide solution is effected with constant stirring, at a temperature not above 35 DEG C., and the pH is maintained between 6 and 10 throughout. The CaSO4 or CaCO3 and calcium cyanamide impurities, e.g. silica or carbonaceous particles, are filtered off. The zinc hydrate is prepared by stirring ZnO with 2 or 3 times its weight of water for 2 to 3 hours. This hydrate is reacted with the cyanamide solution filtrate in 3 to 70% stoichiometric excess for 1 to 2 hours. |
