122 Report of Fakmeks' Institutes 



NEW FORMS OF SOLUBLE NITROGEN 



Dk. L. L. Van Slyke 



Strictly speaking, there are no " new forms of soluble nitrogen," 

 using new in its literal sense. However, extending its meaning to 

 a period of ten years or so, there are three forms to which atten- 

 tion can be called: (1) calcium cyanamid, (2) calcium nitrate, 

 and (3) nitrogen compounds prepared in the so-called wet way. 



CALCIUM CYANAMID 



1. Composition. Calcium cyanamid is a compound containing 

 the elements calcium, carbon and nitrogen. When chemically 

 pure, it contains 35 per cent of nitrogen, but the commercial 

 product, which is commonly known as lime nitrogen, is not pure. 

 The product at present on the American market contains from 

 15 to 16 per cent of nitrogen. It is a fine powder of dark-gray 

 color. 



2. Method of MoAiufacture. The two principal materials used 

 in the preparation of calcium cyanamid are : first, pure nitrogen 

 obtained by liquefaction of air and distillation; second, cal- 

 cium carbide, the substance that is so familiar in the production 

 of acetylene gas. The carbide in the condition of a fine powder is 

 placed in a heated retort, into which the nitrogen is passed. 

 Combination takes place with the resulting formation of impure 

 calcium cyanamid, which is removed from the retort in the form 

 of a hard cake. This is cooled out of contact with the air and then 

 crushed to a powder before packing. The impurities consist in 

 large part of calcium oxide (quicklime) and compounds of iron, 

 silicon, etc., in addition to the carbon formed in the operation, 

 the presence of which is the cause of the dark color of commercial 

 calcium cyanamid. 



There is one large factory in America in successful operation, 

 located at Niagara Falls, which made its first shipment in De- 

 cember, 1909. The product is all shipped to Baltimore, where it 

 is further manipulated before distribution to the trade. The 

 product commonly put out contains 15 to 16 per cent of nitrogen, 

 of which 80 per cent is cyanamid nitrogen and 20 per cent is 

 ammonia nitrogen, or a mixture of ammonia and nitrate nitrogen. 



