The mirror., 1919-10-16
TURN SMOKE AND DUST INTO MONEY
Scientist has Discovered Way to Stop Enormous
Waste of Fuel Through Electrical Precipitation
II. MouIton L

KlzEAKyzlZ
dioxide gas, invisible to the eye,
given off from the stacks of the
smelter, had swept the neighbor-
ing country bare of vegetation for
miles, and it was case of either a
shutdown or suppression of these
destructive discharges.
A full-sized plant of the Cottrel,
type was, accordingly, installed.
The volume of the gases treated
averaged between 100000 and
300, 900 cubic feet per minute, and
during the filtration tests made of
the gases throughout a period of
nine months it was found that the
electrical precipitator recovered
between 80 and 80 per cent of the
suspended matter. With improve
ments in detail of construction, the
efficiency later was raised we'll up
into the nineties.
The general public has only the
faintest notion of the wastage
represented in the fumes and
smokes from belching stacks quite
apart from the benefcient econo-
mics following from their abate-
ment where the nature of these
outpourings is harmful to man and
vegetation. In the smelling of
lead the fume contains anywhere
from 3 to 10 per cent of the vola-
tilted metal in the form of lead
oxide and lead sulphide, with COM
pounds of arsenic and antimony.
This percentage is we'll worth re-
covering. Doctor Cottrell is
authority for the statement that
not less than 36 valuable SUBJ
stances are found in fumes which,
if not collected, would be lost DUR
ing the smelling and refining of
various ores, etc.
At Great Falls, Mont, there
was at one time a daily loss in dust
from the stacks of one of the large
smelters of SITS pounds of cop
per, 106 ounces of silver, and OIL
ounces of gold. By an adequate
provision for dust recovery, this
smelter was able to save in the
course of single year metallic
values amounting to $130, 263.
The blighting gas. sulphur
dioxide, given off from the stacks
of copper smelters can be trans
formed into useful substances by
turning the gas into sulphuric acid
or sulphur. Sulphuric acid is
largely made here by treating
pyrites, and we now consume an
nually in the neighborhood of
$3.50, 900 tons of so per cent sui
phuric acid. To a great extent
this corrosive fluid is a prime con-
stituent in the preparation of fer
tilizers, especially where phos-
phate rock is treated for this pur-
pose. It is also used in convert
ing the ammonia by-products of
cooking ovens into ammonia sui
phate. .Sulphuric acid is in great
demand by explosive factories, oil
refners, steel mills and varied in
dustries engaged in the making of
heavy chemicals. Sulphuric acid
is likewise extensively employed
by smelters and the latter are pay
ing as high as $50 a ton today for
the stuff. Sulphur dioxide is used
in the preparation of wood pulp
for paper making, both as disin-
tegrating and bleaching agent.
In dealing with noxious or OBJ
jectionable gases not necessarily
harmful new aspect of precipita-
tion arises. The electrical treater
can handle only fluids or SUBJ
stances in the shape of particles
and cannot cause the precipitation
of gases, per SO. But these gases
can be made to condense upon
mists in the form of steam or fine
ly sprayed water or upon extreme
ly fine powder or dust purposely
thrown into the sweep of the
gases to effect this. In this way it
Continued on pase sscolunn ~