IMPROVE- MENTS IN THE CONSTRUCTION AND WORKING OF FURNACES FOR PRODUCTION OF IRON, STEEL, AND FERRO-MANGANESE, AND IN PROCESSES CONNECTEU QUEREWITH
Year: 1875

page_text: LETTERS PATENT to Charles William Siemens, of No. 12, Queen Anne's Gate,
Westminster, in the County of Middlesex, for the Invention of “IMPROVE-
MENTS IN THE CONSTRUCTION AND WORKING OF FURNACES FOR
PRODUCTION OF IRON, STEEL, AND FERRO-MANGANESE, AND IN PROCESSES
CONNECTEU QUEREWITH
2:
THE
Westminster, in the County of Middlesex, for the Invention of “IMPROVE-
MENTS IN THE CONSTRUCTION AND WORKING OF FURNACES FOR
PRODUCTION OF IRON, STEEL, AND FERRO-MANGANESE, AND IN PROCESSES
CONNECTED HEREWITH
2:
THE
PROVISIONAL SPECIFICATION left by the said Charles William Siemens
at the Office of the Commissioners of Patents, with his Petition, on the
5th January 1875.
CHARLES WILLIAM SIEMENS of No. 12 Queen Anne's Gate Westminster in
the County of Middlesex. "IMPROVEMENTS IN THE CONSTRUCTION AND WORKING
OF FURNACES FOR THE PRODUCTION OF IRON, STEEL, AND FERRO-MANGANESE,
and IN PROCESSES CONNECTED THEREWITH."
This Invention relates to the construction and working of furnaces for the
production of iron, steel and ferro-manganese, having reference more particularly
to the lining of such furnaces, and to the arrangement of the throats of regenerative
chambers and dust pockets thereof, and to the mode of effecting the preparatory
calcining of the ore to be treated, the production of ferro-manganese for use in
converting into steel, and the casting of the steel into ingot moulds.
For lining rotary furnaces employed in the reduction and conversion of ores as
described in the Specifications of Patents granted to me on the 15th November
1871 No. 3077 and on the 3rd December 1872 No. 3642, according to my present
Invention I employ wood which is not resinous such as poplar, oak, teak, and the
like in the following manner. I cut pieces of length equal to the intended thickness
of the lining and roughly shape them as voussoirs for the cylindrical portion.
These pieces are well dried and immersed in a strong solution of alum, chloride of
iron or other suitable metallic salt so as to be thoroughly impregnated therewith.
The impregnation may be assisted by first extracting the air from the vessel
containing the pieces and the solution, and then applying pressure in the known

page_text: manner; and after drying, the impregnation may be repeated. The pieces of wood
so impregnated are built into the furnace with their fibres radiating or nearly so
each piece being in the first place dipped into a thick paste of bauxite fire-clay or
of oxide of iron mixed with about 20 per cent. of lime, which refractory paste
serves to fill up the interstices between the pieces and to cement the whole into a
solid mass.
In lining a cylindrical rotating furnace in this manner, the pieces may
be varied in their lengths and arranged so as to present a polygonal form in the
interior for the purpose of giving a rolling instead of a sliding movement to the
materials with which the furnace is charged. Instead of thus forming a chamber
of polygonal form, it may be made cylindrical with ribs or irregularities formed in
its surface by introducing blocks of the fused slag from the steel melting furnace,
which having been formed under the action of very intense heat are capable of
resisting the lower temperature of the rotating furnace. The ends of a rotative
furnace lined in this manner may be conical as described in the Specifications above
referred to. I prefer however to make them flat at right angles to the axis or
nearly so with a ring of fire-brick towards the central opening which serves for
the throat at one end and the working door at the other end. In some cases the
preliminary impregnation of the wood above described may be dispensed with,
some kinds of wood being rendered sufficiently incombustible by the refractory
paste or motar used for setting the pieces. The lining above described is applicable
not only to rotating furnaces such as I have referred to more particularly but also
to reducing furnaces generally such as those having a rotating bed of basin form
or having a fixed bed.
In furnaces, such as I described in the Specifications above referred to, and in
other regenerative gas furnaces in which the one throat is made to serve for the
inlet of the flame and also for the outlet of the products of combustion the vertical
wall or midfeather which separates the inlet from the outlet passages is liable to melt
down. To provide against this, according to my present Invention I construct such wall
or midfeather hollow with vertical flues or passages in it through which air circulates
keeping it sufficiently cool to prevent its fusion. For regenerative gas furnaces
employed for converting reduced ore into cast steel, as described in the Specification
of a Patent granted to me on the 28th February 1870 No. 594 where the inlet
for flame is at one side or end of the furnace chamber and the outlet is at the
opposite side or end, I provide according to my present Invention dust pockets or
receptacles for arresting solid matters which may pass with the current from the
furnace and preventing them from encumbering the chequer work of the
regenerators. For this purpose I arrange the air and the gas regenerators in pairs
on each side of the furnace with the said pockets or receptacles between them, that
is to say a pocket between the air and the gas regenerators on the one side and a
like pocket between the air and the gas regenerators on the other side, and I carry
the flues laterally into the pockets and thence vertically upwards till they turn
laterally into the furnace chamber. At the bottom of the pockets there are doors
for clearing out from time to time the dust or cinder that may have accumulated
therein. For tapping into ingot moulds the cast steel produced 1 provide according
to my present Invention a skeleton turntable in front of the furnace, and circularly
arrange on it groups of ingot moulds, each group consisting of a central git
communicating at the bottom with a number of moulds placed round it. These
moulds are slightly tapered and are closed at the top by covers or stoppers with one
or more small holes through them for the escape of air as the steel rises in the
mould. When the furnace is tapped the steel flows by a guiter lined with ganister
or loam into one of the gits brought for the time to face the gutter, and when the
moulds of that group are charged, the gutter is closed by a stopper and the turntable
is moved partly round to bring another of the gits into position for filling. The
stopper employed for closing the gutter serves also to regulate the flow through it,
and the gutter is preferably expanded at one part to form a reservoir for the fluid
metal during the stoppage of the flow. The slag which follows the steel from the
furnace is received in an open box placed on the turntable, which is made of

page_text: skeleton construction to allow the steel to flow on to a pig bed provided below it,
in case of the metal accidentally breaking out from the furnace or overflowing the
gits.
In my former Specifications referred to above I described the addition of spiegel
eisen or ferro-manganese to the bath of steel towards the end of each operation.
For steel of ordinary temper spiegel eisen is well suited to impart the necessary
proportion of carbon and manganese, but if steel is required to be of great ductility
when cold a ferro-manganese containing manganese and iron in nearly equal
proportion is employed. Such ferro-manganese may be advantageously produced
in a rotative furnace lined with wood as above described. For this purpose rich
manganiferous iron ore or a mixture of iron ore with oxide or carbonate of
manganese is ground fine and mixed with about 50 per cent. of small coal or coke,
and the mixture is charged into the rotative chamber while hot. The chamber is
slowly rotated till the chemical reaction is completed producing metallic iron and
manganese. To facilitate the liquefaction of the mass pig metal or spiegel eisen is
added preferably in a divided and heated condition and the rotation is stopped
until the added material is melted and incorporated with the rest. The incor-
poration may be aided by slow rotation of the furnace, and when it is effected the
whole of the materials form a bath of rich ferro-manganese covered by fluid cinder,
all of which is tapped into moulds or on to a pig bed. Lime or other fluxing
agents are used to produce a fluid slag.
For producing malleable iron or reduced metal suitable for being transferred to
a steel melting furnace, the wood lined rotary furnace above described may be
employed, the process being conducted as described in my previous Specifications
above referred to. In working comparatively poor ores I crush and calcine them
beforehand, and for caleining I prefer to employ a revolving furnace such as is
described in the Specification of a Patent granted to me on the 21st May 1869
No. 1575, and to transfer the calcined material in a heated condition to the
reducing furnace, thus saving time and heat. The fluxing materials are passed
with the ore through the caleiner and this progess has in certain cases the effect of
purifying ore from sulphur and phosphorus, these substances being volatilised in the
reaction under the influence of a full red heat. Common salt produces such a
reaction when assisted by vapour of water introduced amongst the heated ore near
the exit orifice.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Charles William Siemens in the Great Seal Patent Office on the
5th July 1875.
CHARLES WILLIAM SIEMENS of No. 12 Queen Anne's Gate Westminster in
the County of Middlesex. "IMPROVEMENTS IN THE CONSTRUCTION AND WORKING
OF FURNACES FOR THE PRODUCTION OF IRON, STEEL AND FERRO-MANGANESE
AND IN PROCESSES CONNECTED THEREWITH."
This Invention relates to the construction and working of furnaces for the
production of iron, steel and ferro-manganese, having reference more particularly
to the lining of such furnaces, and to the arrangement of the throats of
regenerative chambers and dust pockets thereof, and to the mode of effecting
the preparatory calcining of the ore to be treated, the production of ferro-
manganese for use in converting into steel, and the casting of the steel into ingot
moulds.
For lining rotary furnaces employed in the reduction and conversion of ores as
described in the Specs of Patents granted to me on the 15th November 1871
No. 3077 and on the 3rd December 1872 No. 3642, according to my present
Invention employ wood which is not resinous such as poplar, oak, teak, and the
like, in the following manner. I cut pieces of length equal to the intended
thickness of the lining and roughly shaped them as voussoirs for the cylindrical
portion. These pieces are well dried and immersed in a strong solution of alum
or silicate of soda, stannate, manganate or titanate of soda or potash, or other non-
volatile and comparatively infusible salt, so as to be thoroughly impregnated
therewith. The impregnation may be assisted by first extracting the air from the
vessel containing the pieces and the solution, and then applying pressure in any
known manner; and after drying, the impregnation may be repeated or it may be
followed up by an impregnation with hydrochloric acid, calcic chloride, or other
solution which may form a solid and infusible precipitate within the body of the
wood. The pieces of wood so impregnated are built into the furnace with their
fibres radiating or nearly so, each piece being in the first place dipped into a thick
paste of bauxite fire-clay or of ferric oxide mixed with about 20 per cent. of lime,
which refractory paste serves to fill up the interstices between the pieces and to
cement the whole into a solid mass. Or the pieces may be built up with fire-clay
and may be impregnated with the solution above referred to after being placed and
while the furnace is being heated up. This process of impregnation may be
repeated from time to time by pouring a quantity of the solution into the furnace
and by causing it to move about under the influence of the flame. In lining a
cylindrical rotative furnace in this manner, the pieces may be varied in their length
and arranged so as to present a polygonal form in the interior for the purpose of
giving a rolling instead of a sliding movement to the materials with which the
furnace is charged. Instead of thus forming a chamber of polygonal form it may
be made cylindrical with ribs or irregularities formed in its surface by introducing
blocks of the fused slag from the steel melting furnace, which having been formed
under the action of very intense heat are capable of resisting the lower temperature
of the rotative furnace. The ends of the furnace lining may also be formed with
advantage of these blocks, which prefer to cast into moulds of suitable shape
from the steel furnace. The lining above described is applicable not only to
rotating furnaces such as I have referred to more particularly but also to reducing

page_text: and heating furnaces generally. In furnaces such as I have described in the
Spec above referred to, and in other regenerative gas furnaces in which the one
throat is made to serve for the inlet of the flame and also for the outlet of the
products of combustion, the vertical wall or nidfeather which separates the inlet
froin the outlet passages is liable to melt down. To provide against this, according
to my present Invention I construct such wall or midfeather hollow with vertical
flues or passages in it through which air circulates, keeping it sufficiently cool to
prevent its fusion.
Instead of circulating air the combustible gas may with
advantage be made to flow through such separate passage or passages on its way
from the gas producers into the furnace, in which case separate gas regenerators
are dispensed with and the combustible gas is made to flow into the combustion
chamber in a continuous manner, to be there consumed by the alternating current
of highly heated air from the air regenerators. Fig. 1. of the Drawings shews a
longitudinal section through a regenerative rotative furnace constructed with my
above-described improvements applied thereto. Fig. 2 shews a part plan of the
same with section through the inlet and outlet passages and Fig. 3 shews a
transverse section. A A is the wood lining consisting of wedged-shaped blocks
prepared and fitted in the manner above described. The blocks are so formed as
to produce one or more flat surfaces in the chamber as at A' for the purpose before
stated or the blocks at A' as also the end blocks at A2 may be of the steel furnace
slag as before described. Rings of fire-brick B B' are introduced round the
central opening CC which constitute respectively the throat and working door
of the furnace. D D E E' are the inlet and outlet passages for gas and air
coming from the regenerators, the partition or mid-feather F between which is
formed with vertical passages F" through which cold air is made to pass from F2
in order to cool the brickwork, or an arrangement similar to that shewn at Fig. 3
may be adopted, where the passage E serves for the continuous inflow of the
comparatively cool combustible gas from the gas producers, while the heated air
and products of combustion pass alternately in and out through the side
passages D D'. The rotative furnace is supported on rollers P on shafts P¹
carried by a carriage running on rails Q1 so that the furnace can be moved
away from the throat when it is required to clean or repair the passages or
midfeather.
For regenerative gas furnaces employed for converting reduced ore into cast
steel, as described in the Spec", of a Patent granted to me on the 28th February
1870 No. 594, where the inlet for flame is at one side or end of the furnace
chamber and the outlet is at the opposite side or end. I provide according to my
present Invention dust pockets or receptacles for arresting solid matters which
may pass with the current from the furnace, thus preventing them from encum-
bering the chequer work of the regenerators. For this purpose I arrange the air
and the gas regenerators in pairs on each side of the furnace with the said pockets
or receptacles between them, that is to say, a pocket between the air and the gas
regenerators on the one side and a like pocket between the air and the gas
regenerators on the other side, and I carry the flues laterally into the pockets and
thence vertically upwards till they turn laterally into the furnace chamber. At
the bottom of the pockets there are doors for clearing out from time to time the
dust or cinder that may be accumulated therein. Fig. 4 shews a longitudinal
section of a regenerative gas furnace provided with dust pockets to the
gas and
air flues according to my before-described improvements and Fig. shews a
transverse section. G G G G are the dust pockets arranged respectively
between each pair of gas and air regenerators H HI I'; the gas and air flues h
are made to enter these pockets laterally, as shewn, so that as the products
of combustion pass down from the furnace chamber towards the regenerators, any
dust that is carried along with them will fall down into the space Kat the bottom
of the pockets. Access is gained to the spaces K for clearing out the dust through
side doors K¹. In other respects this furnace is similar in construction to those

page_text: described in my previous Specs, and will therefore be readily understood on
reference to the drawing.
For tapping into ingot moulds the cast steel produced, I provide according to my
present Invention a skeleton turntable in front of the furnace, and circularly
arrange on it groups of ingot moulds, each group consisting of a central git com-
municating at the bottom with a number of moulds placed round it. These moulds
are slightly tapered and are closed at the top by covers or stoppers with one or
more small holes through them for the escape of air as the steel rises in the mould.
When the furnace is tapped the steel flows by a gutter lined with ganister or
loam into one of the gits brought for the time to face the gutter, and when the
moulds of that group are charged, the gutter is closed by a stopper and the turn-
table is moved partly round to bring another of the gits into position for filling.
The stopper employed for closing the gutter serves also to regulate the flow through
it, and the gutter is preferably expanded at one part to form a reservoir for the
fluid metal during the stoppage of the flow. The slag which follows the steel from
the furnace is received in an open box placed on the turntable or into a succession
of separate moulds for the production of blocks for furnace bottoms or linings.
The turntable is made of skeleton construction to allow the steel to flow on to a
pig bed provided below it, in case of the metal accidentally breaking out from the
furnace or overflowing the gits. Fig. 6 shews a vertical section and Fig. 7 shews
a sectional plan of one arrangement of the above-described turntable for ingot
moulds. In the pit L beneath the tapping hole of the melting furnace M. is placed
a skeleton turntable O. This consists of a number of rails R radiating horizontally
from a central boss fixed on a vertical shaft R', the rails being supported by tie-
bars R connected to a casting at the upper end of the shaft R' as shewn. This
casting also carries a platform S supported at the circumference by rods S₁ from
the rails R. At their outer ends the rails R are tied together by strong plates T
that carry the ingot moulds U. These are arranged in groups upon plates U¹
carrying a central git U2 communicating with the bottom of each of the moulds
through channels in the plate U₁ as shewn. From the tapping hole of the
furnace M a gutter V lined with ganister extends over the central git, into which
the metal flows from the gutter through a hole which is closed by a stopper V¹
when the moulds of one group are filled, after which the turntable is turned so as
to bring the next group of the moulds under the gutter. If required single ingot
moulds of large dimensions may be placed at W on the turntable into which the
metal is run direct and a ladle X is provided for receiving the slag after the metal
has all been run off, or additional moulds for this purpose may be provided as
above described. Between the groups of ingot moulds are arranged small raised
platforms supported by brackets from the turntable, in which brackets are
holes Y2 for the reception of bars Z by means of which the turntable is turned.
The shaft R is supported by a closed casting a which forms a chamber into which
combustible gas flows from the passage and whence it issues through the pipe c
in the form of an ignited jet for the purpose of heating the passages and the ingot
moulds before being filled. The turntable being all open except at the circum-
ference, any metal that is spilt will fall on to the floor of the pit. In the modified
arrangement shewn at Figs. 8 and 9 the turntable O is of annular form, being
constructed of two rings R R formed of rails connected together by plates T
upon which are placed the ingot moulds U. The turntable is provided with
wheels Orunning on a circular rail O2 on the floor of the pit L; Zis a lever for
moving the turntable. The central platform S is in this case fixed, being built on
the floor of the pit, and a bridge S' is provided by which access is gained to it from
the foundry floor. Hydraulic or other cranes are provided for lifting the ingot
moulds and ingots from the table and for replacing the moulds for the succeeding
casts.
In my former Spec referred to above I described the addition of spiegel eisen
or ferro-manganese to the bath of steel towards the end of each operation. For

page_text: steel of ordinary temper spiegel eisen is well suited to impart the necessary pro-
portion of carbon and manganese, but if steel is required to be of great ductility
when cold, a ferro-manganese containing manganese and iron in nearly equal
proportion is employed. Such ferro-manganese may be advantageously produced
in à rotative furnace lined with wood as above described. For this purpose rich
manganiferous iron ore, or a mixture of iron ore with oxide or carbonate of
manganese is ground fine and mixed with about 50 per cent. of small coke or coal,
and the mixture is charged into the rotative chamber while hot. The chamber is
slowly rotated till the chemical reaction is completed, producing metallic iron and
manganese. To facilitate the liquefaction of the mass pig metal or spiegel eisen
may be added, preferably in a divided and heated condition, and the rotation is
stopped until the added material is melted and incorporated with the rest. The
incorporation may be aided by slow rotation of the furnace, and when it is effected
the whole of the materials form a bath of rich ferro-manganese covered by fluid
cinder, all of which is tapped into moulds or on to a pig bed; lime or other fluxing
agents are used to produce a fluid slag. For producing malleable iron or reduced
metal suitable for being transferred to a steel melting furnace, the wood lined
rotary furnace above described may be employed, the process being conducted as
described in my previous Spec above referred to. Or cast steel may be produced
from metallic ores by one operation in this furnace with the carbonaceous
lining in the manner described in my previous Patent of the 3d Dec. 1872
No. 3642.
In working comparatively poor ores crush and calcine them beforehand, and
for calcining I prefer to employ a revolving furnace such as is described in the
Spec of a Patent granted to me the 21st May 1869 No. 1575, and to transfer
the calcined material in a heated condition to the reducing furnace, thus saving
time and heat this calcining process has in certain cases the effect of purifying
the ore from sulphur and phosphorous, these substances being volatilised in the
reaction under the influence of a full red heat. Common salt produces such a
reaction when assisted by vapour of water introduced amongst the heated ore near
the exit orifice.
Having thus described the nature of my Invention and in what manner the
same is to be performed, I claim :—
First. Lining furnaces, more particularly rotative furnaces used for the reduction
of metallic ores, with wood impregnated with metallic or earthy salts and built up
solidly within the furnace with the fibres standing vertical or nearly so to the
heated surface substantially as herein described.
Second. The employment of blocks of steel furnace slag for lining furnaces such
as are above referred to, either separately or in combination with an impregnated
wood lining.
Third. Constructing the neck of regenerative gas furnaces having the inlet and
ontlet passages contiguous to each other in such a manner that the division wall
between such passages is refrigerated by currents of cold air or by the inflowing
current of combustible gas, substantially as herein described in reference to Figs. 2,
3 and 3 of the Drawings.
Fourth. Producing rich ferro-manganese or cast steel in a rotative regenerative
gas furnace provided with an impregnated wood lining in the manner substantially
as herein-before described.
Fifth. Constructing regenerative gas furnaces for the production of steel on the
open hearth in such a manner that a pocket or receptacle is formed between the
air and gas regenerators on each side for the scoria and ashes carried away from
the furnace by the products of combustion substantially as herein described in
reference to Figs. 4 and 5 of the Drawings.
Sixth. Arranging a skeleton turntable in front of an open hearth steel
melting furnace, with groups of moulds arranged upon the same substantially as

page_text: and for the purposes herein-before described in reference to Figs. 6 to 9 of the
Drawings.
In witness whereof I the said Charles William Siemens have hereunto set
my hand and seal this Fifth day of July in the year of our Lord One
thousand eight hundred and seventy-five.