Lewistown gazette. [volume] (Lewistown, Pa.) 1843-1944, 1858-04-15

es a hot-short iron; but carefully roasted the
sulphur of the pyrites can be mostly eyapo-
rated. The hydrates of the coal formation
are mainly derived from spathic iron, and
! frequently contain car6ontc and sulphuric
acids, which impair the quality OF the metal,
| but can be removed by CAREFUL ROASTING
| OF THE ORE" Here is the first step. We have
seen already, that the ore near Lewistown is
! precisely similar in chemical character with
/ the ores of the coal formations. The oxidis-
| ed outerop contains some Of the original car
Donate from which it was decomposed, which
impairs the quality of the iron, but which
can be removed by careful roasting! We
must begin, then, by roasting the ore cafetut
! ly. On page SO. under the head of Hydra
ted Oxide of lion, Brown Oxide, Hematlte,
BOG Ore" Overman remarks, This whole
class ought to be roasted, not for the purpose
Of oxidation, but in order to drive OH the
acids and destroy >sulphurets and phosphu-
rets, for all the ores Of this class contain more
or less injurious matter. This ore viii bear
a high temperature, If there is no foreign
matter mired ,cM 1t; bat Of this it is very
seldom free" The spathic ore, OF laminated
! carbonate from which the outcrop ore Is de-
composed, requires roasting with great care
! mage 40. 0yerman " CarbOnates require care
! ful treatment In the furnace they melt be-
| fore carbon has any influence on them; and
| if there is any admixture of foreign matter,
| the carbonates are very apt to produce
| small quantity Of white iron, with black elm
/ der The roasting Of carbonates is difficult:
! the best means Of roasting them are totc heat,
/ and if possible, access OF watery vapors,
| partly to carry off the heavy carbonic acid
gas, and partly to prevent too high tempe
rature for if the heat is too strong, the car
Donate melts together with the oxide, and
f,rms a black cinder. Under all circumstan-
ces the ore to be roasted should be broken in
to pieces as small as those usually put into
the blast furnace, say taco o. three inches; if
we neglect this Of course we cannot expect
good result, for it is obvious that large pieces
| will not receive heat and oxygen through their
/ whole body SO soon as smaller pieces and as
| the main object is oxidation, no means should
/ he neglected which will accomplish the end
| in view Stone coal, properly applied, will
! answer; coke or anthracite is preferable. Bad
! or sulphurous coal should he avoided or at
! least coked before used" On this point let
I me add few emphatic words from the same
! high authority: Whether an iron ore should
/ be roasted, is 4 question which very seldom
arises at least this question seldom ought 70
! arise With the exception Of the red impal-
| pabIe oxide, The lohoLe body Of iron ores re-
qusre roasting. The object oi roasting the
an oxide Of iron, the metal can be revived
! THAT is, brought to its original condition of
| native from by means of carbon, more readi-
| ly than when the iron exists in any other
| combination. II IS Of the utmost possible
consequence to recottect this great principle IN
/ The nlGnuf fdcttre Of iron. The metals, with
the exception Of gold, silver, and copper, are
seldom found in their native state. They are
combined with other matter in their native
beds, and it is the study of the metaiIurgist
/ by dissoving this combination, to reduce
| them to their simple condition"
( "Allmatter generally found in iron ore which
| is considered injurious to the metal is more
or less volatile, and expelled by cherry red
| heat; for instance, sulphur, phosphorus, chic
| rine, arsenic, antimony, sulphuric acid, phos
| phoric acid, carbonic acid, &c. A heat suf-
dcieutly strong to oxydize ore, expels all other
! volatile matter and the iron retains oxygen
alone" By roasting the ore carefully We not
! only expel the injurious volatile matters in
| combination with it, but we increase the oxy-
dation Of the ore. and the higher that oxyda-
/ ton is carried lJhat is, the more perfect the
/ roasting the more easily is the metal revived
/ or brought to Its native state. How vain then
| is the attempt to manufacture a large yield Of
! good iron by burdening a furnace with raw
ores AS q general rule, il is dangerous
/ to attempt it with any ore, but With the car
Donates it is impossible The outcrop ore
should be prepared by itself, for the roasting
of the carbonate requires much more care.
/ and short experience will teach in what pro
/ portion they should be used in the burden of
| the furnace.
! / come 2uT 70 ihe question of fuel. 1t is
( fact established by many furnaces running
on this ore, that II makes an admirable iron
with charcoal and cold blast. The iron mada
thus at " Isabella" by Mr.. Duncan, was CT.
cellent; so that at Hope" by Capt. Patton;
Mt Bedford" by Mr.. Cromwell &c, dc.
But the day Of charcoal furnaces is rapidly
closing. The decrease in our forests and the
trifng yield of such furnaces will soon ST.
lence them all in Pennsylvania. We must
have fuel which closely resembles charcoal
in softness and openness of texture, but which
will bear a much heavier burden and blast
The demand for certain kinds Of iron, which
anthracite does not yield, requires such a fuel.
Can we procure it? We can--cheap and in.
exhaustible. Coke is this fuel 1t is thus
described: Fossil coal local dug out Of the
earth) charred deprived Of its bitumen,
sulphur, or other extraneous or volatile mat
ter, by fire, and thus prepared for exciting
intense heat;" (Cleayeland. )-or, to give Les
ley's definition, Coke is the solid carbon and
ash in coal, obtained by driving off the water,
the hydrogen, the sulphur, and any other vol
atile matters which the coal may contain. 1t
isporous, splintery, crystalline and sonorous."
Withoutentering into the history of fossil coal,
it will be sufficient to state that charcoal, btu
minous and anthracite coal are each the result
of vegetation under differing conditions BIZ
luminous coal is mineralized by it's contact
with iron, sulphur, &c. Expel these foreign
substances by fire and submit the residuum
/ to enormous and long continued pressure, and
you have anthracite, which is compact coke
but bituminous coal slowly and carefully Gred
IN rows, stacks or ovens, produces mineral
charcoal which, if the work has been proper.
ly done, will have a purity and open structure
equal to Vegetable charcoal, but Nth much