Idaho County free press. [volume] (Grangeville, Idaho Territory) 1886-current, 1890-08-08
Reverbera.ory Smelling and Stag Constitution


In the reverberatory furnace, the con-
ditions under which the treatment of
ores must be effected differ, markedly,
from those of blast-furnace practice, and
from those of the roasting in Bruckner's
Cylinder. From the initial charge for
the sulphurizing roast, to the final run
ming down, or melting. appropriate mod
itications must be made in the various
operations that have been described in
former papers. in order to meet these
differences.
The reverberatory furnace is simply
an immense oven, upon the floor of
which. the charge is spread out for
treatment; and upon this floor, the ore
must remain until its fusion is effected
Here, we cannot effect the rapid and
perfect mixing in of an added portion.
as is 30 easily accomplished in the
rotary roaster-and in this, we are left
at great disadvantage. But here we
have, also, an advantage in avoiding
one source of trouble from the reduction
of iron as instead of the reducing gases
OF the blast furnace, we can have a
neutral, or an oxidizing flame. In the
blast-furnace, the escaping gases are
forcibly driven mp, between and among
the fragments of ore thus giving the
best possible chance for reactions upon
those fragments. In the reverberatory,
the furnace gases, which are oxidizing
rather than reducing-and may be near
ly neutral-have access to the top sur
face only of the charge, and the general
result should be near approach to that
of fusion in crucible.
The reactions which are described in
the paper on sulphuration roasting, the
oxidation of iron with the simultaneous
combination of it's accompanying sui
phur with some other metal ARE precise
ly the reactions which occur in the or
binary reverberatory practice and
where the charge is properly made up,
of fine material-with sufficient of iron
enlphide &c. in homogeneous mixture,
the complete sulphuration of all the
copper, lead and silver may be effected.
1t seems evident, however, that sulphur
alton can be effected only by actual
direct contact of the fused iron sulphlde
with the particles to be sulphurized or,
perhaps. in small degree. indirectly
through the sulphur and oxygen carry
ing mediation of the Stag. If, there
fore, the iron sulphide he not present
in large excess, it will, on fusion,
run down toward the bottom of the
charge before the sulphuration is COM
pleted, to degree which will leave
the top portion incompletely sulphur
lied. And, therefore, on fusion of the
whole charge, there will be loss in
the Stag from this top portion. If the
iron sulphide be present in sufficient
excess, complete sulphuration of the
whole charge may then be effected but
large portion of the sulphde will run
down before the reactions are over, and
30 the small quantity of matte which is
retained in the Stag will be much richer
than it should be. 1t is evident, also,
mixed the charge may be, the greater
will be the tendency to increase such
losses-~a large lump of sulphde would
run down to the bottom, but with little
effect, save the after one of adulteration
of the matte.
To avoid all these difficulties, so far as
possible, l would make up the finely
crushed material for the charge with
only sufficient of iron sulphide to effect
the desired reactions with certainty
adding a quantity of coal dust more
nearly sufficient for the completion oil
the reactions, as described in my last
paper, than will be permissible in roast
ing for the blast-furnace. All the
necessary fluxes, with little fuor spar
or crushed Stag to start the fritting
should be mixed with the initial charge
it being impracticable to stir, or mix in,
effectively, any portions which may be
added after where concentration of the
patte is desirable. no coal should be
used. Except in making the most eff
fective use of a minimum proportion o.
raw pyrtes--as will be explained else,
where the proportion of sulphide
should be increased from the bottom OIL
the charge to the top. The charge, when
properly made up, should be slowly
heated until fritting begins; and the re-
manning lphides--crushed matte OIL
ore-in quantity sufficient to make ur
the matte product to the required
amount, should then be added to the
top of the charge; and should be mixed
in with the upper part, SO far as prac-
ticable so as to break up the crust which
is formed during the fritting, land so pre-.
vent the formation of sink holes in the
plastic material. and the consequent run
ming down of streams of melted "metal.'
The whole charge may then be run
down together. This method of proceed
ure permits the collection and the wash
out of the richer portions of matte by
the poorer.
These suggestions, so far, apply to the
use of the mono-sulphide alone. Taking
now, our supposed case in matte smet.
ing for silver where the sulphur content
of the raw ore is to be utilized so far as
possible, it is evident that, if the whole