COAL - Clpdigital.org

50 THE COAL TRADE BULLETIN.
COKE FROM LEAN COAL.
In a paper on the manufacture of coke read
before the Metallurgical section of the mining and
metallurgical congress at Liege, Henry Henne-
butte gave the following information and data
regarding coke making from lean coal:
Ever since the seams of coking coals have begun
to exhibit signs of exhaustion, and the growing
depth of the pits has led to the extraction of coal
insufficiently caking for the purpose of making
metallurgical coke—attempts have been made to
manufacture coke from semi-caking, or lean coal.
This problem has been solved with commercial
success.
When coal is coked in an oven its hydrocarbons
are distilled. The vapor tension of the hydrocarbons
is greater the higher the percentage of
hydrogen they possess. The products which come
off first are found (when a given hydrocarbon is
subjected to fractional distillation) to be richer
in hydrogen than the original substance. For,
on rapidly heating a hydrocarbon, the high-hydro­
gen products escape first, the carbon gradually increasing
until that alone is left.
The coking power of a coal is a function of the
amount of hydrocarbons it contains. Thus it is
possible to impart artificially a coking power to
coals by allowing them to absorb suitable hydrocarbons.
However, no coal whose coefficient of
contraction does not at least equal that of its expansion
is suitable for making coke; although,
out of the samples investigated, only 16 per cent.
failed in this respect.
Coke consists of a coherent mass of grains
cemented together by a binder; if, when the temperature
falls considerably, the mass does not
possess a sufficient degree of contractility, irrespective
of the quantity of cementing substance
between each grain, the resulting coke will be
friable and lack cohesion.
In manufacturing coke from non-caking coal, it
is necessary to determine the temperature at
which the driving off of its own volatile matter
becomes completed. The volatile matter passing
through the portions which have become coked,
deposits its dissociated carbon. Thus, if an arti­
ficial addition of hydrocarbons be made, it is
necessary that their temperature of distillation
should correspond with that at which the evolution
of the natural volatile matter of the coke
finishes, otherwise wastage will occur.
The hydrocarbon to be added is simply a coaltar
oxidation product. The coal, and the hydrocarbon,
in a finely pulverized state, are mixed in
a machine of special design, in the proportions
of 97 per cent, of fine coal to 3 per cent, of cement.
The process has been in operation for several
years and has proved a commercial success. By
its means a dense, strong coke, possessing the re­
quired degree of porosity and resistance to crush­
ing, and of great value for use in large blast-fur­
naces, has been regularly produced from coa)
containing 15 per cent, of volatile matter.
COAL PRODUCTION OF THE WORLD.
The following table showing the coal production
of the world was compiled for the American Iron
and Steel Association:
COUNTRIES TONS.
United States 319,102,236
Great Britain 230,334,239
Germany and Luxemburg 162,477.510
France 34,906,418
Belgium 23,796,680
Austria-Hungary 40,628,785
Russia and Finland 17,500,000
Sweden 320,390
Spain 2,587,652
Italy 346,887
Dominion of Canada 6,824,999
Transvaal 2,258,284
Natal 713,548
India 7,438,386
Greece 10,700
New South Wales 6,354,846
New Zealand 1,420,229
Otlier Australia 626.731
Japan 9,701,682
Algeria HO
Other countries (about) 6,238,692
Total 873.535,000
Semet-Solvay Plant at South Chicago.
The construction of the coke plant of the Semet-
Solvay Co. at South Chicago, 111., is progressing
rapidly. The builders hope to have it partly in
operation by October 1. The company a short
time ago, sent out inquiries to the various smokeless
coal producers of West Virginia asking for
prices on 10,000 tons of slack coal to be delivered
monthly at the South Chicago plant, beginning
October 1. According to report the company
will use a portion of the coal they themselves
produce at Boomer, Fayette county, W. Va., mixing
it with smokeless, the combination giving
the coke product a firmer structure. Accepting
10,000 tons of purchased coke to be the amount
consumed monthly the output of coke to be marketed
at Chicago will exceed 100,000 tons per year.
The part this will play in the Chicago market
may be seen from the fact that the statistical
showing of coke received there last year was
only 367,731 tons. This amount, however, does
not include the coke received by the Illinois Steel
Co. and other pig iron producers.