8 CYANAMID MANUFACTURE, CHEMISTRY AND USES 



sold on the basis of its nitrogen content, as determined by 

 analysis. 



The following is a typical analysis of commercial Cyanamid, 



Per cent. 



Calcium cyanamide CaCNj 45-92 



Calcium carbonate CaCOj 4.04 



Calcium sulphide CaS 1.73 



Calcium phosphide CagPj 0.04 



Calcium oxide, free CaO — 



Calcium carbide CaCg — 



Calcium hydroxide Ca(OH )2 26.60 



Free carbon C 13.14 



Iron and alumina R2O3 1*98 



Silica SiOj 1.62 



Magnesia MgO 0.15 



Combined moisture — 3.12 



Free moisture HjO 0.35 



Undetermined — 1.31 



100.00 



COMMERCIAL DERIVATIVES. 



Ammonia. — Steam, at a high temperature and pressure, con- 

 verts calcium cyanamide quantitatively into calcium hydroxide 

 and ammonia, thus forming a convenient source of ammonia 

 for the manufacture of ammonium salts. The carbon, which 

 is in the form of graphite, and the lime, can be used over again 

 for the production of carbide. 



Nitric Acid. — By the Ostwald process, ammonia can be oxi- 

 dized to nitric acid, mixtures of thoria and ceria being used as 

 catalyzers. No external supply of energy is required in this 

 process. 



Cyanides. — When calcium cyanamide and carbon are fused 

 together with alkaline salts, in the absence of carbide the cal- 

 cium cyanamide is converted into calcium cyanide: 



CaCN, -h C — Ca(CN),. 

 The product of this reaction is called a "surrogate." It is used 

 in the recovery of metals by the cyanide process. 



The above reaction is completely reversed in the presence 

 of carbides, hence their absence is imperative in this process. 



