216 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1923 



The large Government nitrate plant at Muscle Shoals, Ala., built 

 according to the cyanamid process, is generally known under the 

 name of United States Nitrate Plant No. 2, and was built for the 

 Government in 1918 for the production of ammonium nitrate for 

 military explosives, the productive capacity of the plant being 110,- 

 000 tons of this product per year. The plant was constructed by the 

 Air Nitrates Corporation, a subsidiary to the American Cyanamid 

 Co., whose process was followed. Incidentally, it might be stated 

 that the plant was completed shortly after the armistice, and one unit 

 (one-fifth the plant capacity) was thereafter put through a two 

 weeks' complete test operation, which thoroughly demonstrated the 

 technical success of the undertaking. 



THE CYANIDE PROCESS 



The fixation of nitrogen in the form of alkali cyanides has not 

 reached any commercial importance, although considerable research 

 work has been done along these lines and a few small plants actually 

 constructed. One of these plants was built by the Government dur- 

 ing the war at Saltville, Va. Its capacity was very small, only 10 

 tons of sodium cyanide per day, the plans being to convert this cya- 

 nide into the highly poisonous gas, hydrocyanic acid, for the war. 



The process of fixation on which the Saltville plant was based is 

 known as the Bucher process, the reaction involved therein being as 

 follows : Na 2 C0 3 -r-4C-f-N 2 =2NaCN-f 3CO. 



The raw materials are soda ash and coke in pulverized form to 

 which iron, also in powdered form, is added, its action, however, be- 

 ing purely catalytic. This material is formed into briquettes, thor- 

 oughly dried, and then heated in retorts at a temperature around 

 1,500° F., while nitrogen is passed through the mass. As high as 

 18 per cent of nitrogen has thus been fixed in the form of cyanide. 



When sodium cyanide is once formed it can be converted into am- 

 monia like cyanamid, and the process has the advantage that in this 

 conversion the soda ash can be recovered and used over again. 

 The iron can also be repeatedly used. 



A cyanide process has also quite recently been invented in Sweden 

 A moderate size plant was built and operated for some time, but is 

 now closed down, and the opinions of specialists seem to be divided 

 as to the commercial success of the process. 



The process is of the continuously operated type, the materials be- 

 ing kept in continuous circulation in such a manner that the nitrified 

 portions are decomposed into ammonia, leaving a solid residue which 

 is returned to the nitrification building with the addition of some 

 fresh material. 



