313 AGRICULTURAL ANALYSIS 



When fused with sodium carbonate, sodium chlorid or other 

 similar materials, all of the nitrogen in the cyanamid is converted 

 into cyanid nitrogen, in other words, the product is a mixture 

 of calcium cyanid, and sodium cyanid. Erlwein draws the 

 following conclusions from the present state of the art : 



Cyanamid may be used directly as a fertilizer in agricul- 

 ture. Those who are interested in the agricultural side of the 

 problem will find interesting comparative pictures of the growth 

 of plants under the fertilizing action of Chile saltpeter and cal- 

 cium cyanamid, etc., in the original German paper. 



2. Calcium cyanamid may be used for the production of ammo- 

 nium sulfate, which is also consumed in large quantities for fer- 

 tilizing purposes. The reaction yielding ammonia is CaCN 2 + 

 3H 2 0=CaCO 3 +2NH 3 . 



3. Cyanamid may be used for the manufacture of dicyanamid, 

 a compound used in the manufacture of anilin dyes and gun 

 powder. By suitable leaching with water and crystallization, 



this compound is obtained in the form of pretty white crystals. The 

 chemical equation is 2CaCN 2 +4H 2 O=2Ca(OH) 2 +(CNNH 2 ) 2 . 



4. Cyanamid may be used as the starting material for the com- 

 mercial manufacture of sodium cyanid or potassium cyanid. Ac- 

 cording to a process devised by Freudenberg, the calcium is 

 melted with sodium chlorid in excess and is thereby transformed 

 almost completely into sodium cyanid. The product obtained in 

 this way, which contains about 22 to 23 per cent, of sodium cy- 

 anid (corresponding to 30 per cent, of potassium cyanid), is either 

 sold directly in this form as so-called "sodium-cyanid substitute" 

 (Cyannatrium-Surrogat) for use in gold metallurgy, or is worked 

 up into chemically pure sodium cyanid or potassium cyanid. 

 Both brands will be made on a commercial scale as soon as a 

 new factory is completed which is in course of erection near 

 Berlin. 



5. As a hardening material for iron and steel, calcium cyan- 

 amid has found a new sphere of application. This application 

 is due to the ability of the cyanamid to give off carbon to the 

 iron which is thereby hardened. This ability is enhanced by the 

 addition of other compounds to the cyanamid and this product is 



