The Butte daily miner. [volume] (Butte, Mont.) 1885-18??, 1886-01-01

DeiOEo Vno Foactlon Oh tne Sulphidee In the
charge reduces IL to 9 protoxide and fita It
blast furnace, Of course. the powerful re-
ducing atmosphere accomplishes this re-
suit at once. but In the reverberatory
smelling, which We are now discussing, the
point mentioned is OF sufficient importance
to DO always borne in mind.
The concentrates are discharged through
a square hole in the hearth nearest the fire.
place into an iron car, and are dumped
over q high wall into q paved Enclosure
convenient to the smelling furnaces.
REvERBERAToRlEs.
Nearly all the reverberatory furnaces in
Butte are constructed after the same model.
and differ from the ordinary Welsh furnace
In the following particulars: The hearth is
wider-eleven feet and more; the crate 10
large, but very shallow, but little lower
and low, and the roof high, 90 that the
space between bridge and roof is much
larger than usual; the arch pitches very
strongly toward the skimming door, SO
that the vulcatory is low; but the trape-
zoidal hole connecting hearth with fue has
an area OF more than SO per cent. greater
than IL the usual custom; the flue 10 broad
and high, and much better results are OBJ.
tanned ~ expanding it rapidly until it
chimney. about fifty. five feet in height, and
with somewhat larger area than the
We'sh furnaces. An increase in height IL Of
NO advantage. Numerous and continued
experiments have proved that the forego.
ing peculiarities are exactly suited to the
fuel in use--a flaming, semi bitu,ninous coal
from Wyoming, which seems only slightly
only slight tendency to coke. and though
ready enough to form massive clinkers II
allowed, gives far better results when
burned in shallow layer, without the
deep clinker bed which forms the chief pecu-
liarity Of the Welsh method Of firing.
With . consumption Of tons OF this coal
in 81 hours =. charges Of 81 tons each OF
The Stag and cleanings that are returned
to the furnace are never counted in the
quantity smelted. It 10 found advanta.
Reous to admit an additional supply OF air
through series VI holes in the root over
the firebridge, and as the best proportional
furnace will flame badly just after throwing
(which should BE- done thoroughly onts il
- hours), hole eight inches square must
be left in the stack below the flue, by which
Sufficient air 10 admitted to cool the lining
when the furnace 10 flaming. The average
charge consists Of about 60 per cent. cal.
cined concentrates, 30 per cent. roasted
uFBC'Cl268 ORG, ana ~ per cent. raw ore,
the screenings OF the frst-class ore being
used for this purpose.
Works that possess no concentrator are
Obliged to use more or less limestone az
fiux, and 1 am informed that at few OF the
smelters 10 the exclamation Of the ore suff.
GENTLY thorough to admit Of the addition
Of such large proportion Of raw ore as l
have indicated.
The furnace 10 tapped after each third
or fourth charge. yielding q matte
assaying from go to 20 per cent.
copper, and from IL to so ounces
in silver, according to the grade Of ore.
am informed that at most Of the works
considerable difficulty IL experienced in
keeping the grade Of the matte a. uniform
as IL desired by the parties to whom II il
shipped. To show that this uniformity IL
perfectly attainable, append q list Of sue
cessive shipments Of about fifteen tons
each, taken from the books Of the furnaces
under my charge. will also state that 30
far from having uniform material to work
with. the ore varied both in quality and
amount almost daily, and the charge SOL
dom remained thesamefor three successive
shifts. The time represented by these ship
ments was the first ten days Of August,
1854.
Percentage Of copper ia shipments Of
matter from tho Parrot works.
No. P1a CExr no. Pc cEN1.