Idaho County free press. [volume] (Grangeville, Idaho Territory) 1886-current, 1890-08-08

*Alumina combines only in company with
another base, as lime. potassa, soda or iron.
On analysis, iron siicate gives 80. 43
per cent. OF silica; calcium silicate, SO. 40
per cent; barium silicate, ID. 0l per cen !;
magnesium silicate, 42.S9 per cent; So
dunn and aluminium double-silicate,
80. 81 per cent.
Manganese oxides may be reckoned
as the same as the corresponding ones
of iron. The black, or dioxide, howev-
er, has no iron analogue-it requires, for
its reduction, nearly twice as much car
bon rs the sesqui-oxide.
Thus 1t will be apparent that the esti-
nation OF the amount of the f1uxes. as
necessary for the best results, in anv
case. will be rather crooked problem.
We should check our practice by ulti-
mate analysis of the slags, as actually
produced. Such analysis should always
show enough OF silica to combine with
all of the bases, in the proportion, to
each, as given above: and there should
be, always, further quantity, in excess
of this amount, to give acidity to the
Stag.
The amount of this exceis of silica
which may be permissible in the fiux-
ing of slliceous ores, will be limited on
ly by the permissible, corresponding de-
crease i'll the fusibllity of the Stag.
Making lime iron Stag, the proportion
of lime used being less than two-thirds
of the weight of the iron oxide, the ex.
cess OF the silica may be equal to one
hall OF the ortho requirement-making
the slag approximately equal to Ca2 Fe 2
Sl3 OlO-and we can hardly 90 beyond
this in practice. A better proportion of
silica Will be an excess equal to one
fourth OF the OBSERVATION-DISCLOSURES
compounds approximating Ca Fe2 Sl2
OF and Ca2 Fe Si2 OF. These latter are
easily fusible, and, l believe, also repre-
sent the practical limits of the propor-
tion of lime; which should not much
exceed the amount, by weight, of the
iron oxides, nor fall much below one
third OF that amount. All of these pro-
portions are for the mixture in the fur.
nace-charge, before the tiuxing.
Aluminium may be i'll combination
with potassium, or with sodium and sill
lea In the gangue-rock; and in such
case, will go into the Stag as indicated in
the table. Unfortunately, polassa and
soda are too expensive to use as huxes.
except when present in the rock, and SO
ultra-alaminous ores may require extra
care In order TO make fusible acid-slae
the normal allumina, lime and iron
compound will require no excess of sill.
ca.
Nothing has been said, SO far. about
The notifications in the carbon reouire-
ment, for reduction, which may be nee
essary, on account of any oxygen Weld.
ing compounds being present in the
gangue. The oxides of manganese and
the sulphate of baryta, and of lime will
require carbon for their reduction. be.
lore they can enter the Stag. How far
this reduction must go, for these sui
pilates, and In what proportion they
may be forced into the Stag without
combining with silica, am as yet una
BILE to tell.
In conclusion, let me say that these
papers have not been offered with the
belief that matte smelling for siyer can
replace the lead. process" under condi-
tons which are favorable for the latter
But where the smelter must paw for the
privilege of using the lead. and must
charge the premium up to the silver
miner. 1t does seem to me that a nracti-
cal system OF utilizing the cheap and