NA TURE 



137 



THURSDAY, SEPTEMBER 29, 1921. 



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The Explosion at the Nitrogen Fixation 

 Works, Oppau. 



0\ the morning of September 21 an ex- 

 plosion causing enormous damage 

 occurred at the nitrogen fixation works of the 

 Badische Anilin und Sodafabrik at Oppau, near 

 Ludwigshafen, on the Rhine. The town of 

 Oppau has been entirely wrecked and presents 

 the appearance of war-devastated ruins, and the 

 neighbouring village of Edigheim has met with 

 the same fate. Numbers from 500 to 2000 are 

 given as estimates of the killed, and the other 

 casualties must be very large. It is stated that 

 the explosion was felt 175 miles away at Munich. 

 Photographs which have come to hand of the 



ene of the disaster show a huge crater. 



The history of the works at Oppau is of great 

 interest, and their importance to Germany was 

 upreme during the war, for it was there that 

 } nthetic ammonia was produced in enormous 

 quantities sufficient, together with ammonia from 

 another synthetic source and from gas works, to 

 enable Germany to obtain nitric acid for the 

 manufacture of high explosives, when the supply 

 of Chile saltpetre, the former source of that acid, 

 had been cut off by the Allies. 



The experimental work on the combination of 

 nitrogen and hydrogen carried out by Haber and 

 his colleagues at Carlsruhe had been closely 

 matched and partly subsidised by the Badische com- 

 pany, which ultimately took over the process, and 

 after a trial in an existing factory it erected 

 the works at Oppau shortly before the 

 NO. 2709, VOL. 108] 



war to operate the Haber-Bosch process. The 

 necessity for fixing nitrogen from the air after 

 the first set-back to the German attack brought 

 about a large extension of these works, until, it 

 is stated, about 200 tons of ammonia a day were 

 produced there. The magnitude of this technical 

 achievement is apparent when one considers the 

 enormous volumes of hydrogen and nitrogen that 

 had to be prepared and purified, the mechanical 

 and chemical difficulties that had to be overcome 

 in bringing about their combination under heat 

 and pressure in large steel bombs charged with 

 a catalyst, and the complexity of the contingent 

 plant for movement of gases and liquids and for 

 absorption and concentration. Many millions 

 sterling were expended on the construction of the 

 plant, which required several thousands of skilled 

 workers to operate it. 



The ammonia thus formed was largely con- 

 verted into nitric acid by the Ostwald-Mittasch 

 method during the war, but since then it has been 

 used for the manufacture of fertilisers, such as 

 ammonium sulphate and ammonium nitrate. The 

 formation of ammonium nitrate is particularly 

 favourable, as it involves oxidation of only a 

 portion of the ammonia to nitric acid. The 

 Germans claim to have overcome the difficulties 

 of the application of this hygroscopic salt for 

 agricultural purposes, and to have had good 

 results from its use. 



In addition to the Oppau factory, a still larger 

 one operating on the same lines has been erected 

 at Merseburg, in central Germany, capable, it is 

 said, of producing 800 tons of ammonia a day. 



While the cause of the disaster will no doubt 

 be fully investigated, the significant statement is 

 attributed to one of the directors that the ex- 

 plosion must have taken place in a store of 

 "ammonium sulphate saltpetre." Presumably a 

 store of ammonium nitrate (Ger. ammonsalpeter) 

 with or without admixture with ammonium 

 sulphate is meant. In another account the quan- 

 tity of this material is given as 4000 tons. 

 Although ammonium nitrate was used in very 

 large quantities in this country during the war for 

 mixing with trinitrotoluene to form amatol, no 

 accidents occurred in handling it. Circumstances 

 have, however, occurred, mostly elsewhere, that 

 have thrown some suspicion on its being quite 

 innocuous from the pomt of view of danger ; but 

 to bring ammonium qitrate, which is an explosive 

 body, up to the pitch of violent explosion or de- 

 tonation requires the application of a very intense 

 initial impulse. This has been done by detonating 



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