CYANAMID — manufacture:, CHEMISTRY AND USES 93 



OTHER MIXTURES. 



With other materials commonly used in fertilizer mixtures 

 Cyanamid can be mixed in any quantities, without prejudicial 

 effect on the valuable constituents. 



ADVANTAGES OF CYANAMID IN FERTILIZER 

 MIXTURES. 



Drying Action. — The free acids in acid phosphate are fre- 

 quently the cause of dampness and poor mechanical condition 

 in mixed fertilizers, causing caking in the bags and making 

 the fertilizer difficult of application through drills. To cor- 

 rect this undesirable condition it is customary to add to the 

 mixture various drying and neutralizing agents. Since the 

 particles of Cyanamid are soft and porous and usually con- 

 tain less than i per cent, moisture they readily absorb free 

 moisture from the acid phosphate or other damp materials 

 with which they come in contact. More important is the 

 action of the lime on the free acids, calcium phosphates tak- 

 ing the place of the sticky phosphoric acid, while the heat 

 generated by the neutralization aids in dissipating the mois- 

 ture uniformly throughout the mixture. This drying action 

 is very valuable to the fertilizer compounder. 



Preventing Loss of Nitric Nitrogen. — It has long been known 

 by fertilizer manufacturers, and has been demonstrated in 

 the laboratory,^ that when sodium or calcium nitrate is mixed 

 with acid phosphate, without the further addition of neu- 

 tralizing agents, there is a loss of nitrogen amounting to from 

 6 to 10 per cent, of the total nitrate nitrogen added. The 

 loss is due to the action of the free acids in the acid phosphate 

 upon the nitrate salts. Thus, with sodium nitrate the reaction 

 probably is : 



2NaN03 + H3PO, — > Na^HPO, -f 2HNO3. 



The nitric acid either.volatilizes as such or is decomposed to 



nitrogen peroxide and oxygen and escapes from the mixture. 



This loss is prevented by Cyanamid in two ways; the free 



^ C. S. Cathcart, Jour. Ind. and Eng. Chem., Vol. 3, No. i, 191 1. 



