IMPROVEMENTS IN THE MANUFACTURE OF IRON SPONGE, IRON AND STEEL and
Year: 1885

page_text: COMPLETE SPECIFICATION
I, WILLIAM ROBERT LAKE, of the firm of Haseltine, Lake & Co, Patent
Agents, Southampton Buildings, in the County of Middlesex do hereby declare
the nature of my invention for "IMPROVEMENTS IN THE MANUFACTURE OF IRON
SPONGE, IRON AND STEEL and in what manner the same is to be performed, to be
particularly described and ascertained in and by the following statement —
"
This Invention relates to the manufacture of iron sponge and of wrought and
steely iron and steel direct from iron ores.
The said invention comprises the treatment of the said iron ores, with or without
a fusible slag, in a furnace having its sole or hearth composed of a mixture of
plumbago, pulverized fire-brick, coal-tar or molasses, or their equivalents.
It also comprises the treatment of the said ores in a reverberatory or similar
furnace having a friable graphitic hearth, the charge of ore being in its normal
condition (or free from added flux) and covered by a layer of graphitic carbon in
heu of the slag or equivalent protecting covering commonly employed, and being
subjected to a sustained dull red heat and finally to a higher and sustained
temperature, as hereinafter described.
Heretofore, in the manufacture of iron and steel direct from the ore, the most
commonly used deoxidizing and carburizing agent has been charcoal, and less
frequently plumbago has been employed. The most common methods of procedure
have involved the mixing of the carbonaceous matter and flux with the ore, and
the employment of a temperature which resulted in the fusion of the metal. When
plumbago has been employed, it has been for the containing vessel in the form of
slabs, crucibles, or solid masses, or for admixture through the charge in the granular
or powered form.
The objection to the use of a solid mass of plumbago as a containing chamber is
that it will not readily act on the ore, while the objection to its use in a pulverized
state, as found in commerce, admixed with the ore is that it is separated from the
charge of ore and carried off by the heated blasts traversing the chamber, or, if the
metal be in a state of fusion (as in carrying on the process for the production of
[Роля 47.1

page_text: "
steely iron), the plumbago rises through the metal and is lost in the slag covering
the same
Moreover, the cost of plumbago is almost prohibitory and the same can be said
of charcoal, as used according to known methods, the quantity required enhancing
greatly the cost of production of the iron
In carrying out the first part of my invention, the iron ores, during treatment,
are in contact with the sole or hearth first above referred to, and yield their
oxygen to the carbon of the plumbago, the iron contained in the ore being reduced
to its metallic state, and sufficiently carburized, after which it is removed from the
furnace and hammered into any desired shape In carrying out this part of my
invention, I have found, in practice, that any ordinary reverberating furnace can
be used when the sole or hearth has been lined with a mixture of the following
ingredients in, or about in, the proportions stated, viz-sixty parts plumbago, and
forty parts pulverized fire-brick, moistened with coal-tar or molasses, or their
This
equivalents, to the consistency of a thick paste, and then thoroughly.died
mixture may be applied as a hearth and lining in the usual manner, and will
preserve its friable character during the process
The iron ore in lumps, or in a fine state, is mixed with about twenty-five per
cent of any fusiblesiron slag. Ordinarily thenalag from a previous) charge (18 used.
This charge is placed in the furnace and, when melted, the heat is increased to
promote the rapid decomposition of the ore, the fusible slag, remaining on top of
the charge in a molten condition, protects the converted iron from reoxidation, and
the newly made iron sponge is taken from the furnace and hammered into blooms
of any desired size, and the operation continued
In carrying out the second part of my invention, the graphite preferably
employed by me is that known in commerce as "graphitic carbon," such as is found
an the United States at Cranston, Rhode Island, and in other localities, it is of an
impure character, containing earthy matter and iron in considerable quantities', can
be obtained at comparatively low prices, and is known in trade as "Graphitic
Carbon" to distinguish it from "Plumbago" of commerce
The furnace employed may be an ordinary reverberatory or any of its many
well known equivalents The hearth or sole of this furnace is provided with a
friable graphitic covering, which I prefer to form as follows, that is to say -I take
of plumbago, or of the "Graphitic Carbon" hereinbefore referred to, pulverized, an
amount equal to sixty (60) per cent, more or less, of the whole mass, add thereto
about forty (40) per cent of pulverized fire-brick, and mix the mass intimately,
and add a sufficient quantity of an adhesive carbonaceous binder, such as molasses
'or coal-tar,' to enable the mass to be spread as a sole and lining for the furnace
This "hearth, when dry, will be compacts and yet sufficiently friable to yield its
carbonaceous matter gradually to the superimposed ore
.
The hearth may, if desired, be formed by covering, the sole with a bed of
graphitic lumps from six (6) to twelve (12) inches in depth,' protecting, the flue-.
bridge and bridge-wall thereby
1
On such a sole or' hearth, the ore, preferably without flux of any character, and
in the condition in which it comes from the mine, is charged to a suitable depth,
say from one (1) to four (4) inches and is then covered by a protective layer of
Graphitic Carbon."
66
This protective layer is composed of the "Graphitic Carbon" in lumps or small
pieces, substantially in the condition in which it comes from the. mine.
For heating the furnace and charge, any suitable sold or gaseous fuel-may be
used, provided always that it is of a character which will admit of controlsson that
a uniform temperature can be maintained The charge is first subjected to a
-temperature not exceeding fifteen hundred degrees, (1500°) Lort two thousand
degrees (2000°) Fahrenheit, or such a' temperature as will maintain the interior of
the furnace at a dull red heat. This temperature is maintained until the orejas
deoxidized, which will take from five (5) to seven (7) hours,

page_text: It will be observed that this stage of the process is conducted at a temperature
too low to fuse the metal When this deoxidation of the ore is completed, the
temperature of the furnace is raised to about from two thousand degrees (2000°)
to two thousand five hundred degrees (2500°) Fahrenheit, sufficient to cause the
agglutination of the sponge, and the mass can then be balled for removal to the
blooming apparatus. The second stage, or stage of agglomeration of the sponge
will occupy from one (1) to two (2) hours, if carefully conducted, which it should
be in order to avoid the fusion of the metal and the formation of a slaggy sponge
such as the majority of sponges produced by processes heretofore practised.
If, however, it is desired to produce steel or steely iron, this second stage of the
heating process must be prolonged at the sustained higher temperature, some six
(6) or seven (7) hours, which can be readily determined by the operator, and
necessarily varies according to the more or less refractory character of the ore
The steelified mass is then balled and removed to the blooming apparatus as above
specified.
The following advantages result from my improved processes - First, there is no
such loss of material and uncertainty of result as when charcoal or plumbago in a
pulverized state is used admixed with the ore, secondly, there is no lack of the
deoxidizing and carburiang agent, or retardation of the process, such as occur
when solid containing vessels or soles of a non-friable character are employed,
thirdly, the open character of the top covering of lump "graphitic" carbon permits
the circulation, through the mass, of the heated gases, and, fourthly, while the ore
18 fully protected from the direct action of the flame by the graphitic covering,
there is an absence of any extraneous substances which would induce the formation
of slaggy sponge in case of the temperature temporarily becoming excessive in the
agglomerating stage.
Having now particularly described and ascertained the nature of the said
invention and in what manner the same is to be performed, as communicated to
me by my foreign correspondent, I declare that what I claim is
First The process, substantially as hereinbefore set forth, of making wrought
ron direct from iron ores by melting them in a furnace having its sole or hearth
composed of a mixture of plumbago or graphite, pulverized fire-brick and coal-tar
or molasses, or their equivalents, as above specified
Second The process herein described for the production of iron sponge direct
from the ore, which process consists in placing a charge of the ore on a friable
graphitic hearth, covering the charge with a layer of graphitic lumps, and then
subjecting the charge to a dull red sustained heat until deoxidation is accomplished,
substantially as, and for the purposes, specified
Third The process herein described, which consists in placing a charge of the
ore on a friable graphitic hearth, covering the charge of ore with a layer of
graphitic lumps, subjecting the charge to a dull red sustained heat until deoxi-
dation takes place, and then slightly increasing the heat for a suitable period of
time to agglomerate the mass so that the sponge can be balled and removed to the
blooming apparatus for the production of wrought iron, as hereinbefore described,
or for a suitable longer period for the production of steelified iron or steel, as
herein before described
HASELTINE, LAKE & Co,
For the Applicant.