NOYES: NITROGEN PROBLEM IN RELATION TO WAR 385 



mass is heated, the reaction begins and becomes violent, and the 

 ammonia is allowed to collect up to a pressure of 12 to 15 at- 

 mospheres, when it is blown off. Then, after the reaction has 

 spent itself, the residue is again charged with steam so as to get a 

 complete removal of ammonia. When carried out properly, it 

 is practicable to get substantially all of the original nitrogen in 

 the form of ammonia. This gives ammonia free from organic 

 matter, except that it contains some acetylene, coming from the 

 calcium carbide present. 



2. I speak next of the cyanide process, in which the reaction 

 that takes place is, in its net result, as follows : 



NaaCOa + 4C + N2 = 2NaCN + SCO. 



A mixture of soda-ash with finely powdered coke and iron is 

 heated at about 1000°C. in nitrogen gas. There is a consider- 

 able conversion of the sodium carbonate into sodium cyanide, 

 with evolution of carbon monoxide. The iron acts simply as a 

 catalytic agent. This operation is carried out in a number of 

 different ways. In one of the forms of furnace, so-called ''bri- 

 quets," which are really pencils made by moistening the mixture 

 and squirting it through a die, are fed down through a long tube 

 8 or 10 feet high, which is heated on the outside by flue gases 

 from the combustion of coal. The heating gases pass around the 

 outside of the tube. The charge feeds slowly down through the 

 heated zone and is drawn out from time to time by a special 

 device at the bottom.. 



As in the case of cyanamide, so in this case also, to get ammonia 

 we have to treat the product with steam. If we treat it at a low 

 temperature the cyanide gives ammonia and sodium formate: 



NaCN + 2H2O = HCOONa + NH3. 



When the formate is heated it breaks up, yielding sodium car- 

 bonate : 



2HC00Na = NaoCOs + CO + H,. 



Thus the sodium carbonate used in the process is regenerated. 

 Really, all that is consumed is the carbon, and the nitrogen taken 

 from the air. 



