Evening star. [volume] (Washington, D.C.) 1854-1972, 1912-10-20
WHERE GRAPHITE
COMES FROM
BY RENE BACHE

| BY RENE BACHE
IN the central part Of the Mexican State of
Sonora, twenty miles from the mining
town of La Colorado, is one of the most desc
late spots on earth. A few rude shacks give
sign of human occupancy. and there are
other evidences to show that mining opera
tons are going on. Here and there are huge
heaps of some intensely black stuff
black stuff is graphite. Not only that, but
it is from this source that the world gets
most of the material for its best pencils
The stuff, oddly enough, is obtained from
coal beds, which in places have turned into
graphite In fact, the same beds are actu-
ally being mined in other spots for coal.
Biologists say that the metamorphosis was
brought about by plutonic agency,-granite
"dikes" pushing their way up from molten
hot strata down below, and changing the
coal into graphite, which today is soft and
friable enough to be dug out with plckax
and shovel.
On being brought to the surface, it is
spread out in the hot sun to dry, and then
not much larger than ST. Bernard dogs haul
it to La Colorado, whence it is forwarded by
rail to Michigan for treatment.
Water is SO scarce in the graphite-producing
locality, that it is doled out in kerosene cans,
ten gallons day to each family. There is
not enough of it for reckless washing, SO that
the miners look like negroes
The famous Siberian graphite is hard to
get out, transportation facilities in that part
of the world being poor, and even the best
German graphite has to be f1oated in water
and settled no fewer than ninety times in
order to rid it of its impurity. But the
IL, <l-t@
crate treatment. Velvety soft and smooth
in the hand After being ground, it is "air
f1oated'; that is to say, exposed to gentle
blast of air. The heavy particles grit set
tie first, and are thus separated out. What
remains is particles almost infinitely small,
like SCOT.
The graphite thus refined is mixed with
clay in certain proportions for making pen
ellis. A good deal of clay is used for hard
pencil leads; less of it for soft. The more
clay, the harder the pencil. The pencil
with big lead, extremely soft, such as car
penters use, has only enough clay to hold
the particles Of graphite together.
for lubricant. 1t is also employed extern
sively in the mixing of paints, to give "body."
The familiar shiny look of gunpowder is
given by graphite, which furnishes coating
for the individual grains and prevents them
from sticking together. Other uses of graph
lite are in electrotyping and manufacture of
| stove polish.
The State of Georgia produces seventeen
thousand tons Of graphite a year. 1t is of
such poor quality, however, as to be of little
use except to blacken phosphate fertilizers.
Most farmers will not believe that such fer
tiizers are rich unless they are black.
Edward G.. Acheson, the wizard of Niagara
Falls, has invented a process for making
graphite from coal by exposing the latter
to enormously high heat in the electric fur
mace. By this means he obtains graphite
so fine that when mixed with water it will
pass with the water through ordinary filter
paper. He claims that it is actually molecu-
lar. This graphite is now used for a variety
of purposes, including the manufacture of
huge electrodes for electric furnaces.
For high temperature crucbles the only
| suitable graphite is that obtained from Cey-
lon, which has an unusual structure, being
fibrous. Mixed with clay for binder, its
| fibers interlock, and with expansion and con-
| traction they work in and out, so that the
| crucible does not break when heated or
cooled. Such cruciblcs are made from an
inch high to sizes big enough to hold gallons