BULLETIN 37, U. S. DEPARTMENT OF AGRICULTURE. 
SULPHATE OF AMMONIA. 
Bituminous coal contains 1.2 to 1.34 per cent of combined nitro- 
gen. In the destructive distillation of coal for the production of 
coke 33 per cent of this nitrogen is evolved, as shown in Table III. 1 
Table III. — Nitrogen from the production of coke. 
Form in which nitrogen is evolved. 
Amounts. 
Form in which nitrogen is evolved. 
Amounts. 
Remaining in the coke 
Per cent. 
63.7 
20.3 
8.1 
Per cent. 
2 9 
Recoverable as ammonia 
.25 
As elementary nitrogen in gas 
.3 
Other volatile substances, carbonaceous in character, are, of course, 
given off, such as gas of high calorific value, coal tar, benzol, etc., 
and constitute the main distillation products. 
In Table IV the nitrogen of a ton of coal and products resulting 
from the distillation of that weight have been calculated to pounds 
of ammonium sulphate. 2 
Table IV. — Nitrogen per ton of coal and products produced from distillation of a ton 
of coal. 
Constituent. 
Ammonium 
sulphate per 
ton of coal. 
Constituent. 
Ammonium 
sulphate per 
ton of coal. 
Pounds. 
122.6 
Pounds. 
0.3 
Nitrogen in cyanide 
Total 
.4 
25.0 
78.2 
12.0 
3.5 
119.4 
Nitrogen in 10,000 cubic feet of gas — 
Nitrogen in tar (90 pounds per ton) . . . 
3.2 
In the main, coal is distilled in this country in that form of coke 
oven, the beehive oven, which does not admit of the recovery of the 
distillation products. Instead, they are allowed to go to waste. So 
we are indebted to the by-product recovery oven for the main supply 
of ammonium sulphate. The amount recovered is valued at about 
$4,000,000, while the recoverable ammonia annually destroyed in 
the coking processes by the beehive ovens is valued at $22,000,000. 3 
In the manufacture of producer gas by the Mond process, where 
the distillation takes place in the presence of steam, 80 pounds of 
ammonium sulphate are obtained per ton of coal. This is four times 
as much as that obtained from an equal weight of coal in the retort 
process. 
i Pennock, J. Ind. Eng. Chem., 4, 174 (1912). 
Pennock, loc. cit. 
^Parsons, Hearst's Magazine, January, 1913, p. 128. 
