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

page_text: COMPLETE SPECIFICATION
I, WILLIAM ROBERT LAKE, of the firm of Haseltine, Lake, and 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 APPARATUS THEREFOR" 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 wrought or steely
iron and steel direct from iron ore, and to apparatus therefor
The said invention comprises a method or process which consists in intermingling,
with the ore, lumps of graphitic carbon, placing the charge in a furnace having a
friable graphitic lining, covering the said charge with a layer of lumps of graphitic
carbon, and subjecting it first to a sustained dull red heat and subsequently to a
higher and sustained temperature, as hereinafter specified
The said invention also comprises an improved construction and arrangement of
a deoxidizing and carburizing furnace, so that the said process can be continuously
conducted or carried on therein
The said invention also comprises the forming of the bed or hearth of an
ore-reducing furnace, adapted to carry out such process, of graphite or plumbago
in lumps as hereinafter described
Heretofore, in the manufacture of Iron Sponge and Malleable Iron directly from
the ore, carbon in various forms, such as charcoal or plumbago, together with
various fluxes, protective coverings of slag or the like, have been used, and, in
cases where it has been desired to obtain steel or steely iron, scrap iron, iron
shavings, or wrought iron in other forms have been added to the charge
Plumbago has been also employed as a material for crucibles or containing vessels,
in, or in conjunction with, fire-clays to form furnace linings to avoid silicious
linings which are often detrimental.
The main objections to the methods commonly practised may be briefly stated
as follows, vizt-first plumbago linings and crucibles, as heretofore employed, do

page_text: not yield up the carbon with sufficient readiness and thus retard the process to the
detriment of the product, secondly, where the carbon is used in the ordinary
condition, vizas a powdered mass admixed with the ore, it cannot be uniformly
distributed, is drifted out and carried off by the blasts, producing irregularity in
the results obtained and thirdly, when used in conjunction with a fusible slag
covering for the ore, it rises into the fusible slag and the greater portion is lost
without obtaining any useful results
To these objections must be added the material one of the high price of
plumbago, and the large amount of charcoal and other forms of soft carbons
required, which add materially to the expense of producing wrought iron or steel
from the ore by the methods now commonly practised
In carrying out my improved process, I make use, by preference, of the impioved
'continuous process" furnace hereinafter described, in which a moderate and
controllable temperature can be maintained
This furnace has, by preference, the improved sole or health of friable graphitic
lumps hereinafter described.
The ore, as taken from the mines, is intermingled with lumps of "graphitic
carbon" (preferably without flux), the said carbon constituting such a percentage
of the charge as shall approximate the quantity required to deoxidize the ore
(which percentage can readily be ascertained by analysis), say about from twenty
(20) to thirty (30) per cent, and a charge of the mixture is placed in the furnace
The charge is then preferably covered with a layer of "graphitic carbon" in lumps,
the said layer being preferably about one or two inches thick The layer of
intermingled ore and graphitic lumps composing the charge may vary from
four (4) to eight (8) inches in depth
The "Graphitic Carbon" referred to 18 an impure graphite containing a
considerable quantity of earthy matters, iron, and other substances and of a
character such as that found in the United States at Cranston, Rhode Island and
elsewhere, and distinguished in the trade there as "Graphitic Carbon," being much
cheaper, and more readily obtained than "Plumbago" so called and employed in
the arts.
The furnace is then raised to, and maintained at, a dull red heat, say about
from fifteen hundred degrees (1500°) to two thousand degrees (2000°) Fahrenheit,
the temperature being varied according to the more or less refractory nature of the
ores, which temperature must be such that deoxidation of the ore will take place
without danger of fusion. This temperature is sustained (if an ordinary furnace
be used) for from five (5) to seven (7) hours, by which time deoxidation will have
been completed and an iron sponge, containing the free metal enclosed in its earthy
matrix, will have been obtained The charge is then subjected to a higher
temperature, sufficient to cause an agglomeration of the mass or the agglutination
of the contained metal, (say from two thousand degrees (2000°) to two thousand
five hundred degrees (2500°) Fahrenheit or more) but not sufficiently high to fuse
the mass
When the charge has been subjected to this increased temperature for from
one (1) to two (2) hours, the mass can be balled and removed to the blooming
apparatus for reduction to wrought iron, but, if a steel or steely iron is to be
obtained, this stage of the process must be prolonged some six (6) or seven (7)
hours, which time can be readily determined by the operator and necessarily varies
according to the more or less refractory character of the ore, as above specibed
The steelined mass is then balled and removed to the blooming apparatus, as
above specified During this second stage of the process, care should be taken to
avoid excessive temperature, as fusion of the metal would ensure the formation of
slaggy sponge of deteriorated character
The times required for the different steps or stages of this process are greatly
reduced, if my improved furnace be employed as hereinafter specified
The advantages of my process are first, the friable bed readily yields its carbon
to the super-imposed ore, secondly, the lumps of graphitic carbon interposed

page_text: between the lumps of ore, lighten up the mass, and permit the circulation of the
heat-bearing gases through the mass, while the carbon is immediately presented to
the ore to be deoxidized, and in such form that the carbon cannot be drifted or
swept off by the blasts of gas, or otherwise, and thirdly, the covering of the ore,
while it is of a character to protect it from the direct and injurious action of the
flame, is also of such character as to obviate, in a great measure, the evils attendant
on the use of fusible slag, as well as the loss of graphite by its being carried off in
the slag
The improved furnace is illustrated in the accompanying drawing, in which
Figure 1 is a longitudinal vertical section of the said furnace
Figure 2 is a horizontal section of the rear end of the furnace on the line y, y,
Figure 1, and
Figure 3 is a vertical transverse section on the line x, x, Figure 1
Like letters indicate corresponding parts throughout the drawing
The advantages of the improved furnace are first-a preparatory or drying and
heating chamber for the ore and carbon is provided, wherein all moisture is
expelled and a preliminary heating of the matter to be treated takes place,
secondly-the deoxidizing and carburizing hearth or chamber is so placed at the
rear of the furnace, and at the discharge end of the drying or preparatory chamber,
that it will be uniformly heated and the beat thereof maintained without
variation, and thudly-a balling hearth is provided and so arranged with relation
to the deoxidizing and carburizing hearth as to receive the charge deoxidized
therefrom and thus enable the furnace to be worked continuously
The balling hearth may be of the usual silicious character, the deoxidizing hearth
is provided with a friable graphitic covering, either in compact form, or preferably
in the form of lumps as hereinafter described
Into this ash-
In the drawing, A, A indicate brick arches supporting the sole or plate B of the
furnace, which should be about double the length as well as double the width of
ordinary reverberatory furnaces At one end of this furnace is the usual or any
approved fire-chamber a having an ash-pit 6 closed by the door c
pit a blast pipe & delivers There is an ordinary fire-bridge e, at the back of
which, and parallel therewith, is the transverse bridge f, which divides the
chamber into a balling hearth C located in direct proximity to the fire-chamber
where the highest heats prevail, and a deoxidizing carburizing chamber D distant
from the fire-chamber a, or where a lower dull red or deoxidizing temperature
prevails
The balling hearth C may have the usual sand bottom or any approved fettling
used in like chambers, but the deoxidizing and carburizing hearth D 18 covered,
for a depth of from four to six inches, with a friable graphitic bottom or with
friable graphitic lumps L, as hereinafter described
This deoxidizing hearth D may, if desired, be divided longitudinally by a slight
bridge h (part of which is shown in Figure 2) for the purpose hereinafter specified.
a, c, and d' d' indicate working doors for the fire-chamber and plates
Supported on, and projecting into, the rear end of the furnace, is a vertical
feeding and drying chamber Ĕ, which is, by preference, a cylindrical fire-brick
stack some ten or twelve feet, more or less, in height, and of suitable diameter, say
froin fifteen inches to two feet, having an opening or door e¹ below, through which
it discharges or feeds down the ore on to the deoxidizing and carburizing hearth
This feeding and drying chamber is encompassed at its base by the flues w, w, by
which the waste gases or products of combustion escape to a flue W extending to a
stack, beneath a boiler or to any other desired point
S, S indicate dampers, which may be inserted in the flues w, w, if, in the working
of the furnace, it becomes necessary or desirable to change the draft from one to.
the other side of the hearth D
The above is a general description of a form of furnace which I have found very
effective for the purposes hereinbefore set forth, and which may be varied in,

page_text: detail without departing from the nature of my invention, provided that the
characteristic features and relative arrangement of the chambers are preserved
The devices being of the general character herein before set forth will be
operated as follows that is to say -The deoxidizing and carburizing agent
employed is intermingled with the ore which is to form the charge As a matter
of general direction I will say that I have found 20 per cent of graphitic carbon
to 80 per cent of ore sufficient.
The charge of ore and the deoxidizing agent, which generally contains more or
less moisture, are then charged into the drying and feeding chamber E and therein
subjected to the transmitted heat from the furnace for several hours or during
the deoxidation of the previous charge The waste products from the furnace pass
around the base of this chamber E through the waste flues w w, and into the main
flue W, so far as I am aware none of the waste products pass through the charge in
the drying and feeding chamber
From the drying and feeding chamber, the charge properly dried and heated, 18,
when desired, drawn down upon the graphitic hearth of the deoxidizing and
carburizing chamber D, it is spread out so as to be fully subjected to the currents
of heated gases or products of combustion, the covering of graphitic lumps having
been applied as desired, and is retained on the said hearth until the deoxidation,
or the deoxidation and the required carburization is completed When this 18
accomplished, the charge is drawn in small masses, or in bulk, over the bridge-
wall on to the halling hearth C, where it is subjected to a higher temperature,
(sufficiently high to cause the agglomeration of the mass) and is balled in the
usual manner and removed to the blooming apparatus
The above is a general statement of the manner in which the furnace is worked,
but, in practice, it will be noted that, after the first charge in chamber E is ready
to be drawn on the deoxidizing hearth D, the working of the furnace will become
continuous, as the ore and carbon composing the charge can be fed into the
chamber E from time to time as they sink therein The charge for the deoxidizing
and carburizing hearth D can be drawn first on one side of the hearth (or bridge
wall if such is used) and then on the other, from the hearth D, the deoxidized
and carburized ore sponge can be drawn on to the balling hearth C in like
order
In practice, I have found that the first charge in chamber E can be prepared for
the deoxidizing hearth in four (4) or five (5) hours, and thereafter the necessary
amount of one and graphitic lumps added to the top of the charge in chamber E
will be fully prepared by the time it reaches the discharge-door e¹ The charge,
as it comes from the chamber E, will require about an hour for treatment on the
hearth D and then can be transferred to the balling hearth C, where it can be
balled ready for removal in from twenty minutes to half an hour, so that the
furnace is practically continuous in its operation
If sponge only is wanted, it is drawn as soon as deoxidation is complete without
transferring it to the balling hearth, but, if wrought iron is desired, the sponge 18
transferred to the balling hearth C and thence to the blooming apparatus, while,
if steel or steely iron is desired, the ore, after it is deoxidized or becomes sponge,
1s retained in the hearth D a further time proportionate to the degree of car-
burization required (the temperature of the furnace being meantime sufficiently
raised) after which it is transferred to the balling hearth C and thence to the
blooming apparatus as before specified
The advantages of this part of my Invention are the simplicity of the furnace-
devices, the continuous character of the operations capable of being conducted
therein, and the great reduction of time required in the several steps of the
process
The third part of my Invention consists of an improved sole or lining for the
reducing and carburizing furnace adapted to carry out my improved process herein
described.

page_text: The active ingredient composing the hearth or lining is graphite, either in the
well known form of plumbago so termed in commerce, or preferably the much
cheaper, less pure, less commonly known graphitic carbon of trade such as 18
obtained in the United States, at Cranston Rhode, Island and other known
localities
The bed or hearth I form of lumps preferably of about the size of a walnut
or a hen's egg, as such sizes can be packed and levelled conveniently and yet
present numerous angles and surfaces from which the fine carbon is readily
worn off
These lumps are charged upon the sole of the furnace so as to cover the same
for a depth of from six (6) to twelve (12) inches (six inches will do, but ten or
twelve inches is better), and are spread out so as to protect the fire-bridge, flue-
bridge and side walls and form a shallow basin for the reception of the ore to
be heated
The ore to be deoxidized and reduced to sponge is charged on this bed to the
depth of several inches, when it may be covered with a protecting covering of slag
or graphitic lumps, and deoxidized in a suitable manner
When the sponge is removed, the bed of graphitic lumps will be found to
have become more or less compact, and to have sunk several inches It can be
immediately restored to its former depth by a top dressing of fresh lumps, and
the next charge of ore introduced, without diminishing the heat of the furnace
I have herein before spoken generally of graphitic lumps as various kinds of
graphite can be used for the purpose of my invention For instance, plumbago
of commerce, or the graphitic, carbon above referred to (pulverized) can be mixed
with a small per centage of pulverized fire-brick, the mass compressed into lumps
of suitable size (preferably having angular projections and kiln dried so as to
form friable lumps, and the bed formed of such lumps, as herein before specified,
but I prefer the graphitic carbon such as is found in the United States of America
at Cranston, Rhode Island and other places and which can be obtained for five (5)
or six (6) dollars per ton, can be taken in lump form, substantially as it is mined,
and applied in the formation of the hearth or bed as hereinbefore set forth
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 herein described for the production of Iron Sponge direct
from the ore, which process consists in placing a charge of the ore, intermingled
with lumps of graphitic carbon, on a friable graphitic hearth and subjecting the
charge to a dull red sustained heat until deoxidation of the ore 18 accomplished,
substantially as, and for the purposes, specified
Second The process herein described for the production of Iron Sponge direct
from the ore, which process consists in placing a change of the ore intermingled
with lumps of graphitic carbon, on a friable graphitic hearth, covering the charge
with a layer of graphitic carbon in lumps, and finally subjecting the charge to a
dull red sustained heat until deoxidation of the ore is accomplished, substantially
as, and for the purposes, specihed
Third The process herein described which consists in placing a charge of the
ore, intermingled with lumps of graphitic carbon, on a friable graphitic hearth,
covering the charge with a layer of graphitic lumps, subjecting the charge thus
formed first to the action of a dull red sustained heat until deoxidation is accom-
plished, and then to a higher sustained heat, below the fusing point of the metal,
for a suitable period for the production of wrought iron as hereinbefore described,
or for a suitable longer period for the production of steelified iron or steel, as
described
Fourth The process herein described which consists in placing a charge of the
ore, intermingled with lumps of graphitic carbon, on a friable graphitic hearth,
subjecting the charge thus formed fist to the action of a dull red sustained heat

page_text: until deoxidation is accomplished, and then to a higher sustained heat, below the
fusing point of the metal, for 'a suitable period of time for the production of
wrought iron as herein before described, or for a suitable longer period for the
production of steelified iron or steel, as described
Fifth A deoxiding furnace for the treatment of ores, which furnace has 'a
balling hearth, and a deoxidizing hearth (provided with a graphitic bottom),
'arranged in sequence, substantially as, and for the purposes, specified
'Sixth The combination, in a furnace for deoxidizing ores, of a feeding and
drying chamber for preliminary treatment of the charge and a deoxidizing hearth
having a graphitic bottom, substantially as, and for the purposes, specified
Seventh In a furnace for deoxidizing ores, the combination of a balling
hearth, a deoxidizing hearth having a graphitic bottom, and a preliminary drying
and feed chamber for receiving the fresh charge, all arranged in sequence, sub-
stantially as, and for the purposes, specified
Eighth A hearth or bed for a deoxidizing ore-reducing furnace composed of
graphitic lumps, substantially as, and for the purposes, specified
D12 1- FM 100K
HASELTINE, LAKE & Co,
For the Applicant