Burlington weekly free press. [volume] (Burlington, Vt.) 1866-1928, 1918-02-21
THE STORY OF CARBON.
Raw Material Extensively Used In the
Manufacture Of Electrical Apparatus.
furror, 49, r~o,, rr,Vuo.N


(From the Troy Times.)
From the very beginning of the cleo
trical industry carbon has been used in
the manufacture Of arc lamps, motors
and generators. batteries. special lamps
and a thousand other devices.
Carbon is a very common material in
nature, especially in the form Of a coal
and charcoal, graphite and the diamond.
1t Is a non-metallc substance without
taste or order
Carbon Is very abundant in chemical
combination, especially in the carbon
ates. and 1t Is the chief constituent of
all organic substances. The raw materi-
ais, from which carbon. products are
manufactured. consist chiefly Of coke in
In its different forms, as petroleum coke
and gas retort coke. lamp black or SCOT,
and both natural and artificial graphites
Lamp black is a very finely divided form
Of carbon obtained from the incomplete
combustion Of oils or gas. All these forms
Of carbon must be carefully selected and
prepared before they can be used in manu-
featuring processes. The particular ma
terial which furnishes the greatest bulk
for the carbon manufacturer is coke.
| Gas retort coke is obtained from illumin-
ating gas retorts where 1t collects on the
ceiling of the retUrts in the form of
thin plates of hard and very nearly pure
carbon. This was formerly the chief
source of raw material for the manu-
fActure Of commercial carbon. It IL now
comparatively little used and its place
has been largely taken by petroleum coke.
| Petroleum coke is obtained from the
fractional distillation of crude petroleum
in thDc voan
Is carried to the point of dryness AS in
the manufacture Of parafin oils The
retorts where distillation is effected are
large steel cylinders, placed horizontally
and fired from below. When the process
Is completed there remains in the bottom
OF the retort n solid cake of coke the
length OF the retort and two to three feet
thick In the centre. This Is a brilliant
black. vtreous substance, somewhat re-
sembling glass In appearance. with a very
porous. spongy structure except for an
inch or two at the bottom of the cake,
where the impurities contained in the
crude oil have settled to form a more
dense mass which naturally contains a
much greater proportion of ash than
I the main portion of the cake. The mass
Of coke in the retort is broken with a
pick into convenient size for handling.
lots and shipped in box cars
Petroleum coke is used in the manu-
facture of dry and wet battery elec-
trodes. in the electrodes used in electro
thermic and electrochemical apparatus. in
many types of commutator brushes for
electric motors and generators, and in
carbon contacts, circuit breakers, light.
ming arresters, resistance units, etc. 1t Is
also the raw material from which car.
I borundum and artificial graphite are de.
I rived by subjecting it to high tempera.
r lures in an electric furnace.
The words graphite" ''plumbago" and
BLACK lead" refer to the same chemical
substance. but though apparently synony.
nous they have a certain trade sgnifi.
canoe applying to the region where the
mineral is produced. Graphite" is found
, in the United States; BLACK Lead" is i'm
, ported from Austria. Germany and Italy
and "Plumbago" comes from Ceylon
which furnishes the main supply of nat.
ural graphite in the world. Thus lead
pencils. black lead stove polish, graphit,
paint and lubricants and plumbago cru
ctbles are established trade names which
J. have their particular meaning to thos,
I dealing in these products.
i Natural graphite occurs in two form
-amorphous and crystalline. The amor
5 phous form does not occur pure, but Il
Q always associated with other foreign sub
stances which affect its use. The crys
talline form occurs both in mass and ir
leaves or flakes disseminated through tn
Q containing rock. In Ceylon 1t is found il
s large masses sometimes weighing severa
}, hundred pounds. while the American for
,. nation usually occurs in small laminate,
/. flakes. 1t is mined in much the same wa,
as coal, crushed. concentrated and separa
ted from impurities by air or water float
J. ing"
Q The worlds supply Of graphite is ap
d proximately half amorphous and hal
:. crystalline. OF the crystalline variet,
n probably more than eighty per cent. 1
d produced in Ceylon. and the remainde
e supplied by Madagascar and the mine
Q In New York and Alabama. The high
d est grade of crystalline graphite come
: from Ticonderoga. N. Y. Korea produce
the largest quantity of amorphous graph
lite and the smaller supplies are obtaine,
from Germany. Austria, Mexico, Rhod
4 Island and Canada. Probably more tina
8 one-half of the worlds output Of crystal
r the graphite Is absorbed in the manufac
II ture OF crucibles. Both forms of graphit
are extensively used in the manufactur
OF generator and motor brushes.