The Ftjcation of Nitrugeyi 9 



The fixation of nitrogen may be made by (l) electrical 

 methods or by (2) chemical methods, and although the 

 electrical method, such as the Birkeland Eyde process, requires 

 about 30 times more energy than the chemical method, e.g., the 

 direct synthetical method, yet from the economic standpoint 

 it is not certain that the chemical methods are the better ; for, 

 from the point of view of capital expenditure, the arc processes 

 have a good deal in their favour. 



Mr. Kilburn Scott has been working on this problem in this 

 country for some years past, and he has devised a special electric 

 furnace for the production of nitric acid, which differs from those 

 used on the continent for the same purpose, in that it is a self- 

 contained three phase unit. The furnace is filled with three 

 triangular metal electrodes. The arcs are struck between the 

 electrodes where they are near together at the bottom, and they are 

 spread out in flames by the flow of air. When the air comes in 

 contact with the rapidly rotating triple arc flames, combination 

 between the nitrogen and the oxygen take place with the 

 formation of nitric oxide. The nitric oxide must be cooled as 

 rapidly as possible, and to facilitate this an arrangement is fitted 

 to the furnace to absorb the heat from the hot gases. And as the 

 hot gases pass away they are used to heat the incoming air. 

 The normal yield of nitric acid is about 50 gms per kw. hr, and 

 with the three phase furnace the yield has been raised to about 

 66 gms per kw. hr. The other part of the process is similar to 

 what I have described under the Birkeland Eyde system. 



Dr. Maxted, on the other hand, favours the method of the 

 direct synthesis of ammonia and its subsequent oxidation to 

 nitric acid, and he estimates that the cost in that case cannot be 

 more than £15 per ton. And he states that so far as power 

 and raw material are concerned the formation of ammonia by 

 direct synthesis is a process more than twice as efficient as the 

 cyanamide process and more than six times as efficient ^s the arc 

 process. The direct synthesis of ammonia with the subsequent 

 oxidation to nitric acid is by far the most economical means of 



