New-York tribune., 1872-11-06
UTILIZATION or LRoN SAC.

A GREAT BURDEN TO THE IRON INDUSTRY
STAG, WHAT 1T Is, AND now PRODUCED
EFFORTS TO TURN 1T TO sOSlE USE-GERMAN
AND FRENCH Observation-Disclosures
OF BPICK AND ARTIFICIAL STONE.
To ths Edftor OF The Tribune.
SIR: In all manufacturing operations there
are constantly found various incidental products with
no ready or apparent such substances become al
most of necessity dead loss both TO The manuacturer
and 10 the community always enhancing the cost OF the
articles produced, aud sometimes rendering their pro
ducon actually unprOhtable II is therefore matter
Of great economic value whenever such waste materials
can by any practicable DO brought into use and
removed from the position o weights and burdens
ANY one who mas visited iron works must have oo-
served the immense piles Of CLASSY and cndery mate-
rial known By the OF Stag, which drawn on the
surface OF tho melted iron In the furnace and thrown out
IN heaps around tue works. This substance Is mainly
silicaie Of lime though also containing small anon1SQ
iron and OF various other mineral ingrebePss The
manner Of It's production may q brins7 described
toWa: IN ia biast-furnaee tie ores used are oxides
Of iron, and these must be so treated as TO
expel the oxygen and separate tho pure metal This
done by causing the oxygen 70 unite with the carbon
OF the fuel combustion, and thus to form earbonio
acid gas which OF into the air at
the top Of the stack But ali the OF iron to say
nothing of the COAL contain small amounts OF various
impurities principally iu the way OF sand tsliea). clay
lalumina) &C. These have also TO be eliminated; It Is
therefore necessary to employ what is known lux
and this IN iron manufacture limestone carbonate Of
hmc) The carbonc acid Of the limestone Is driven on
by the heat Of the furnace in ordinary kiln, leav
ing the pure me which enters into combination at its
high temperature with the silica present in the and
forms a silicate Of lime, mixed Yltl some alumna.
little rou and various other impurities IL Is for this
r0h that the charge Of iron furnace consists OF
alternate layers Of ore, coal, and mestQRe. Wien all
these substances are fused together into molten
in the intense heat Of the furnace the iron sinks 70 the
bottom aud IL there tapped and run out; while the
mingled impurities floating is surface as liquid sag
are drawn 90 above, and carried Away and thrown out
how great Is 0i sag pf5dd6sd may be esti
mated By considering that 1t represents al the ash OF
the coal all the impurities OF the and all the solid
material Of the limestone. II has had value Qr use
hitherto save at for making roads the fur
mace for filing in made land II the works for
tunate to DO near large river or bay and 80 it is
generally dead weight the iron-masters. No one
who has visited the great Tredegar Works Richmond,
can fail TO have noticed the enormous heaps Of
this material that stretch along the canal and extend
out and form Islands In the James River AZ New York.
and at other points the Hudson there the great
source of alng along the shore; and in these
the loss is made good by extending the Of ground
around the works But in Orange County, in PeDnsyl
vania aud indeed generally the Stag is OF the heav
lest burdens Ql this industry.
EFFORTS TO UTILIZE THE!wAsTE MATERIAL.
The production Of slag from ordinary blast furnace
has estimated at twice that OF the by weight
and as II Is far lighter the bulk will be about Eve times
that OF the iron. Different furnaces vary. however,
these proportions The Manhattan IRON w0rEs Tor IN
stance making 80 OF iron per day. compute
their Stag about 40 But in all cases men, tools
and machinery are requisite TO handle and remove IL
and the great OF heat given out in the cooling
sIch masses from a melted state is wholly lost az no
YufIg of In
find OF turning furnace slags 10 account,
has therefore long been problem of nportan 10 iron
masters; and large amounts Of time, money, and skill
have expended IN more or less unsuccessful
fefnpts AT Lebanon Penn. for instance the sIag has
been cast thin blocks OF about foot square, and
used to some extent for paving sidewalks, sc. But al
not very satisfactory. This has been one great
difficulty Win all attempts to make IL into
ains good deal OF from the furnace and az il so
iines rapidly, II beeone7 CLASSY, porous gpd brittle.
continent Of Europe have gradually attained 20 mucn
greater degree Of success in this important matter than
has ever before been achieved The great variety on
uses for which slags he made available with
saving aud even sOmeumes with actual profit, causes
surprise IA well as pleasure Prof n Egeston. of the
Europe last summer collected large number OF very
ceum Of Natural History Winter and also The
er wen worthy of perusal and OF srndy by ali who
are Interested in tue iron industry in mis- country. Many
s tan they are abroad but II il none the less desr
for American ron-masrs 20 examine the subject Wtn
care and 10 see what 1t is possible to do in tnis i'm
pOrtant economy.
BRICK AND ARTIFICIAL sroEE MADE FROM Stag.
Among the improved methods described BY Prof.
Egeston In his paper the first aud simplest il that by
which the Stag Is devitred; caused consolidate
into hard and compact material suitable for building
purposes instead Of assuming It's ordinary brittle and
classy character. Tn. be- done by cooling II under
pressure. Various devices have been employed IN order
10 effect this result IN the Stag Is pressed
INTO blocks ia mOids, sand these blocks then an
nea led days. Extensive buildings connected
OF the siesiau iron-works constructed ~
hese Stag bricks some similar experiments have beeh
n progress of late at the Manhattan Works above this
y. The most important prOcess Of tins KIND however
that OF a Belgian engineer, NJ. sepucre VINO has sue
eeded In forming Artificial stone Nnch ~
exceedingly strong aud satisfactory. The Stag
. made 10 How continuously into ha-lnshaped
excavation, whose s0pnR sides allow
floating crust that forms on the op 70 rise steadily
the cavity fills without breaking, and without DecOm-
ng attached 10 the sides. When The receptacle Is fan
b. ton crust Is covered WITH sand ashes 10 prevent
he TOO rapid cooling OF the liquid mass below. In tins
.av inc cooling gDes on slowly aud under cOusideru-
Ia pressure. After a weeks time, more lcss. the
sbs and crust are cleared on and the greater part of
he mass Is found be- compact and OF good qua y Ia
doutsd the stuno thus produced his become actual
ource uf prud though sold lt tow order % la
rOduce It. Seventy percent ~ the total Stag made
stone at an expense Of scarrey more than bali the