CYANAMID — MANUFACTURE, CHEMISTRY AND USES 



15 



of CaO to 56 of N, or equal weights of each. By reference 

 to the curves in Fig. i it is seen that if the ordinate represent- 

 ing the amount of CaO present as Ca(OH)2 is subtracted 

 from the ordinate of total CaO, the ordinate of CaO combined 

 in other forms (with cyanamide) would coincide with the 

 ordinate of nitrogen present as cyanamide ; that is, the amounts 

 of CaO and N present are in the relation demanded by the 

 formula CaCCN.NH),. 



On long standing of the solution, the acid salt Ca(CN.NH)2 

 decomposes, forming principally urea, some dicyandiamide. 



H-Total^ - 

 0a0-7ota] 



D- as 

 Cyanamide ■'^^ 



Fig. I.— Variation of nitrogen and calcium in a solution of lime-nitrogen. 



and small quantities of melamine, amidodicyanic acid and 

 ammonia. The dicyandiamide diminishes slowly, and finally 

 probably disappears entirely. This is shown in the following 

 analyses by G. Liberi^ of a solution made by extracting lime- 

 nitrogen containing ^8.63 per cent, cyanamide nitrogen, with 

 twenty times its weight of cold water. The nitrogen figures 

 are given as a percentage of the dry lime-nitrogen. 



1 Ann. R. Staz. Chim. Agrar. Sper di Roma., 191 1, Vol. V, Series II. 



