INDUSTRIAL A N D ENGIATEERINGCHEMISTRY
82
abundance of evidence which shows that there is a serious decomposition of ammonia by almost all bodies except silica a t temperatures favorable to the catalytic oxidation of ammonia. 2"s 3 0 = Nz 3Hz0 Imison and his eo-authors6 give the following figures :
+
+
Ammonia decomposed a t 350' C.by: Wrought iron.. Nickel Aluminium ..................................... Silver.. ........................................ Silica less t h a n . . ................................
................................. .........................................
Per rent 81.47 35.25 10.8 3.85 1.0
The writer found that ammonia was completely decomposed when passed through pumice heated to 750" C. Parsons gives the results obtained by G. B. Taylor in his work on this subject. Per cent NHa Destroved
..
Pieces of pure aluminium sheet.. 0.0 Vitrified silica.. . . . . . . . . . . . . . . . . . 0 . 8 Nickel wire 2 mm. diam. staples., 1.4 Nickel wire' 2 mm. diam. staples.. 11.3 Nickel wire' 2 mm. diam. staples.. 22.0 Porcelain, $ieces from dish. . . . . . . 0 0 34.0 2.3 Alundum cement, briquets
........{
Temperature
c.
550 880 500 580 890 700 710
590
The selection of silica tubing for the experimental work
of this paper was for the purpose of eliminating as far as 6
Imison. A. Russel and Russel, J . SOC.Chem. Ind., 41, 371 (1922).
Vol. 16, No. I
possible any preliminary decomposition of ammonia, the gases coming in contact with silica alone when heated to conversion temperature. On the commercial scale silica-lined iron tubes may be used. Imison suggests a coat of paint made by mixing barium sulfate with a solution of sodium silicate. The action of iron is prevented by this protective covering. From Taylor's results it is evident that aluminium may be used without any deleterious effect on the preheated gases. The temperature withstood by this metal has the upper limit of 650" C., so that the metal is not suitable for the converter itself. The production of nitric acid from ammonia is a comparatively simple process and the apparatus required can be made up easily with comparatively little expense. Since synthetic ammonia has passed its experimental stage, it is a question of but a short time when 50 per cent nitric acid may be made a t an exceedingly low cost per pound. Cheap ammonia will also be obtained from the cyanamide process. The Kahn bill pending in Congress for the U. S. Army control of Muscle Shoals, Alabama, makes a demand for twelve million dollars, two million for repairs of the plant, which originally cost 70 million. Ten million dollars are sought for operative costs. The yearly output of 200,000 tons of cyanamide equivalent to 35,000 tons of ammonia is the beginning of a great enterprise
Smoke Screen and Bombing Tests Official photographs, publzshed by permission of the U. S. A r m y Air Service
1-A half-mile smoke screen from titanium tetrachloride laid from an airplane in eighteen seconds. This screen remained opaque for 4 or 5 minutes and then began to be broken up by the wind as shown here. ' 2-A 1200-pound bomb of T N T dropped from about 3000 feet and striking an obsolete battleship, passing through the ship and emerging at the water line as indicated. This took place during the bombing experiments off the
Virginia capes in September 1923. 3-The result of the 1200pound bomb. Note that the decks have been ewept clear of all superstructures and that the vessel is rapidly filling. Shortly after this photograph was taken, the vessel turned turtle and sank. These experiments again demonstrated the community of interests which exists for the h'avy, the Air Service, and the Chemical Warfare Service in both offense and defense.
