IMPROVEMENTS IN THE PROCESS FOR THE PRODUCTION OF IRON AND STEEL AND IN FURNACES or ApparaTUS EMPLOYED for that PuRPOSE
Year: 1872

page_text: LETTERS PATENT to Charles William Siemens, of No. 3, Great George
Street, Westminster, in the County of Middlesex, for the Invention
of "IMPROVEMENTS IN THE PROCESS FOR THE PRODUCTION OF IRON AND STEEL
AND IN FURNACES or ApparaTUS EMPLOYED for that PuRPOSE.”
PROVISIONAL SPECIFICATION left by the said Charles William Siemens
at the Office of the Commissioners of Patents, with his Petition, on
the 28th September 1872.
I, CHARLES WILLIAM SIEMENS, of No. 3, Great George Street,
Westminster, in the County of Middlesex, do hereby declare the nature
of the said Invention for "IMPROVEMENTS IN THE PROCESS FOR THE PRODUCTION
OF IRON AND STEEL AND IN FURNACES OR APPARATUS EMPLOYED FOR THAT PURPOSE,"
to be as follows:-
In the Specification of a Patent obtained by me, dated the 15th
November 1871, No. 3077, I described a mode of producing wrought
iron and steel by melting iron ores (mixed with fluxing materials), and
by effecting a reduction or precipitation of the metallic iron contained

page_text: in the fiery solution by means of carbonaceous reagents cither in the
solid or gascous condition. I farther described that the iron so produced
might be rolled or otherwise worked as wrought iron, or might be
transferred to a steel melting furnace for the production of cast steel.
I farther described that the balls of precipitated iron could be formed in
the same heated chamber or furnace where the ore had been previously
melted, or that the ore was by preference to be melted in a continuous
manner in one furnace and to be transferred from time to time by
tapping into a separate furnace (by preference a rotary furnace) for
the purpose of effecting the reduction or separation of the metallic iron
from the slag or scoria.
According to my present Invention I effect the melting of the ore in
a continuous manner, and its reduction into metallic iron or steel in a
non-continuous or intermittent manner in one and the same furnace,
which I prefer to be a regenerative gas furnace. For this purpose the
flame bed of the furnace is divided into two or more compartments; into
one of these the ore to be melted descends in a continuous manner
through a hopper or hoppers under the influence of intense heat; the
other compartment or compartments under the same furnace roof have
the sole or bottom formed into one, two, or more basins of refractory
material for the reception at will of fluid ore. In front of cach basin a
working door and tap hole are provided similar to those of a puddling
furnace. The sides of each basin are raised slightly above the level of
the bottom of the melting compartment except in one place, where a
channel or gutter is formed by which fluid ore can flow into the basin
unless it is stopped by banking the gutter by the temporary introduction
of refractory material.
The mode of working this apparatus may be varied according to the
nature of the materials employed or of the iron or steel to be produced.
If coke or anthracite are the available reducing agents I reduce them to
a fine powder and mix them with an equal weight of pulverulent iron
ore, such as hematite or calcined spathous ore, though these proportions
may be varied according to the nature of the ore treated. To this
mixture I add milk of lime or argillaceous matter in a divided state,
or a mixture of them for the purpose of producing a somewhat binding
carbonaceous compound which is put aside ready for use. When the
furnace is fully heated and the rough ore descending through the hopper
or hoppers has begun to melt I prevent the inflow of the fluid mass

page_text: into any of the basins by banking up the channels to them with the
carbonaceous compound just described. I also line one or more of the
basins with the same material, and removing the bank by a bar or hook
allow a portion of the fluid ore to flow into the same. The fluid ore
being thus brought into contact with the carbonaceous lining ebullition
ensues and continues until the whole of the lining is consumed, by
which time the iron contained in the solution will be for the most part
if not entirely reduced to a granular metallic condition. Towards the
end of this operation the chemical reaction is aided by the introduction
of a branch or pole of wood through the working door and stirring the
mass therewith; or a gas rabble, as described in the Specification above
referred to, may be employed to assist the precipitation and agglomera-
tion of the metal; or without the carbonaceous lining the reduction
may be effected entirely either by poling or by forcing carbonaceous
gas through the fluid ore in the basin. If poling is largely resorted to
bundles of wood may be used, which are forced down into the fluid ore-
by a forked bar of iron or equivalent means.
When the precipitation of the iron has been sufficiently accomplished
(for which purpose the temperature of the fluid ore has to be maintained
at a point above that of welding iron) I remove the scoriac by tapping or
by lowering the sill plate of the working door. The iron remaining in
the basin may then be balled and worked into blooms or bars, and this
iron will be found to be very pure and free from sulphur or phosphorus,
these impurities having been removed with the scoria or fluid cinder.
The temper of the iron may be varied by changing the proportions of
the reducing agent, being soft if little, and hard or steely if much carbon
be employed.
The balls of reduced iron may be transferred to a steel melting furnace
for the production of cast steel; but cast steel may also be produced
within the ore melting and reducing furnace itself by conducting the
process as above described to the point of removing the fluid cinder,
when instead of balling and removing the iron precipitate pig metal or
spiegel eisen is added to it. This in melting will combine with the iron
and form a bath of cast steel of any required temper, which may be
tapped into moulds in the usual way.
Two of the basins may be used alternately by directing the stream of
fluid ore successively into the one and the other; or two of the basins

page_text: may be made to supplement each other by effecting the precipitation of
the iron in the one and the conversion into cast steel in the other, in
which case the partially balled precipitate is transferred from the one
basin to the other across the dividing bank without exposing it to the
cooling or oxydising influence of the air. When this mode of operating 5
is adopted I prefer to line the basin where precipitation is effected with
aluminous or calcareous substances, and that where the conversion into
cast steel is accomplished with siliceous substances.
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 27th March 1873.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, Charles
WILLIAM SIEMENS, of No. 3, Great George Street, Westminster, in the
County of Middlesex, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twenty-eighth day of September, in the
year of our Lord One thousand cight hundred and seventy-two, in the
thirty-sixth year of Her reign, did, for Herself, Her heirs and successors,
give and grant unto me, the said Charles William Siemens, Her special
license that I, the said Charles William Siemens, my executors, adminis-
trators, and assigns, or such others as I, the said Charles William
Siemens, my executors, administrators, and assigns, should at any time
agree with, and no others, from time to time and at all times thereafter
during the term therein expressed, should and lawfully might make,
use, cxcrcise, and vend, within the United Kingdom of Great Britain
and Ireland, the Channel Islands, and Isle of Man, an Invention for
"IMPROVEMENTS IN THE PROCESS FOR THE PRODUCTION OF IRON AND STEEL AND IN
FURNACES OR APPARATUS EMPLOYED FOR THAT PURPOSE," upon the condition
(amongst others) that I, the said Charles William Siemens, my executors
or administrators, by an instrument in writing under my, or their, or one
of their hands and seals, should particularly describe and ascertain the
nature of the said Invention, and in what manner the same was to
be performed, and cause the same to be filed in the Great Seal Patent
Office within six calendar months next and immediately after the date
of the said Letters Patent.

page_text: NOW KNOW YE, that I, the said Charles William Siemens, do
hereby declare the nature of the said Invention, and in what manner
the same is to be performed, to be particularly described and ascertained
in and by the following statement thereof, that is to say :-
In the Specification of a Patent obtained by me, dated the 15th
November 1871, No. 3077, I described a mode of producing wrought
iron and steel by melting iron ores (mixed with fluxing materials) and
by effecting a reduction or precipitation of the metallic iron contained
in the fiery solution by means of carbonaceous reagents either in the
solid or gascous condition. I farther described that the iron so produced
might be rolled or otherwise worked as wrought iron, or might be
transferred to a steel melting furnace for the production of cast steel.
I farther described that the balls of precipitated iron could be formed in
the same heated chamber or furnace where the ore had been previously
melted, or that the ore was by preference to be melted in a continuous
manner in one furnace and to be transferred from time to time by
tapping into a separate furnace (by preference a rotary furnace) for the
purpose of effecting the reduction or separation of the metallic iron from
the slag or scoria.
According to my present Invention I effect the melting of the ore in
a continuous manner, and its reduction into metallic iron or steel in a
non-continuous or intermittent manner in one and the same furnace,
which I prefer to be a regenerative gas furnace. For this purpose the
flame bed of the furnace is divided into two or more compartments;
into one of these the ore to be melted descends in a continuous manner
through a hopper or hoppers or may be supplied by side doors and is
subjected to the influence of intense heat; the other compartment or
compartments under the same furnace roof have the sole or bottom
formed into one, two, or more basins of refractory material for the
reception at will of fluid ore. In front of each basin a working door
and tap hole are provided similar to those of a puddling furnace. The
sides of each basin are raised slightly above the level of the bottom of
the melting compartment except in one place where a channel or gutter
is formed by which fluid ore can flow into the basin unless it is stopped
by banking the gutter by the temporary introduction of refractory
material. Or the sides of each basin may be continuously raised and
the fluid or semi-fluid contents can be raked over the bank from one to
another.

page_text: The construction of this furnace which I employ by preference is
shewn on the accompanying Sheet of Drawings, in which Figure 1
shews a longitudinal section of the furnace on line 1, 1, (Figure 2);
Figure 2 shews a sectional plan on line 2, 2, (Figure 1); Figure 3
shews a part front elevation and a part transverse section on line 3, 3,
(Figure 1); Figure 4 shows a transverse section on line 4, 4, (Figure 1);
and Figure 5 shows a part longitudinal section of a modified con-
struction.
The regenerative chambers A and gas and air flues B, B', leading
therefrom to the melting and reducing furnace C are arranged and
operate in a well-known manner, and need not be further described.
The bed of the furnace C is formed in two levels; the upper level is
hollowed out to form a basin D, and the lower level is also hollowed
out to form two pools or basins E and E¹ which are separated by a
bank or bridge F; working doors G, G', are provided at each side of the
furnace to give access to the upper basin D, and in front of the furnace
are two working doors H, H³, with tap holes I, I', beneath them, one for
cach of the lower basins E, E'.
The mode of working this furnace may be varied according to the
nature of the materials employed, or of the iron or steel to be produced.
If coke or anthracite are the available reducing agents I reduce them
into a fine powder and mix them with an equal weight of pulverulent
iron ore, such as hacmatite or calcined spathose ore, though these pro-
portions may be varied according to the nature of the ore to be treated.
To this mixture I add milk of lime or argillaceous matter in a divided
state or a mixture of them, for the purpose of making a somewhat
binding carbonaceous compound with which I line the lower basins
E, E, and I also form banks of the same compound at D', D', to prevent
the melted orc from running into the basins E, E', from the basin D
until required. The rough ore mixed with suitable flux is charged into a
the basin D through the doors G, G'; or it might be charged through
hoppers in the crown of the furnace, and when a sufficient quantity of
the ore has become melted I remove a portion of the bank which
separates the basin D from one of the lower basins E or E' by means
of a bar or hook, so as to allow the melted matter to flow into the ;
lower basin; or without removing the bank I rake over it a portion
of the fluid or semi-fluid mass. The fused ore being thus brought into
contact with the carbonaceous lining of the lower basin ebullition

page_text: ensues and continues until the whole of the lining is consumed, by
which time the iron contained in the solution will be for the most
part if not entirely reduced to a granular metallic condition. The
chemical reaction may be aided by introducing a branch or pole of
wood through the working door, and stirring the mass therewith; or a
tubular rabble through which carbonaceous gas is forced, such as I
described in the Specification above referred to, may be employed to
assist in precipitation and agglomeration of the iron.
The reduction may also be effected without the carbonaceous lining
above described by the use of a gas rabble, or by poling with wood.
When the precipitation of the iron has been sufficiently accomplished
(for which purpose the temperature of the material has to be main-
tained at a point above that of welding iron) I remove the scoria by
tapping, or by lowering the sill plate of the working door, so as to run
off the fluid contents of the basin, leaving the metallic iron in a partly
coherent condition. This iron may thereupon be worked into balls,
which can be removed from the furnace, and worked into blooms or
bars of iron, which iron will be very pure or free from sulphur or
phosphorus, these impurities having been removed with tho scoria or
fluid cinder.
The temper of the iron may be varied by changing the proportions of
the reducing agent employed, being soft if little, and hard or steely if
much carbon be added.
The balls of reduced iron may be transferred to a steel melting
furnace for the production of cast steel; but cast steel may also be
produced within the ore melting and reducing furnace itself by con-
ducting the process as above described to the point of removing the
fluid cinder, when, instead of balling and removing the iron precipitate,
pig metal or spiegel eisen is added to it. This in melting will combine
with the iron, and form a bath of cast steel of any required temper,
which may be tapped into moulds in the usual way.
The two basins E, E', may be used alternately by directing the stream
of fluid ore from the basin D successively into the one and the other.
Or the two basins may be made to supplement each other by effecting
the precipitation in the one and the conversion into cast steel in the
other, in which case the partially balled precipitate is transferred from
one basin to the other across the bank F without exposing it to the

page_text: cooling or oxidizing influence of the air. When this mode of operating
is adopted I prefer to line the basin where the precipitation is effected
with aluminous or calcareous substances, and that where the conversion
into cast steel is accomplished with siliceous substances, passages K, K,
are formed at the sides of and beneath the bed of the furnace, communi- {
cating with the external atmosphere in order to cool the bed.
Having thus described the nature of my Invention and in what
manner the same is to be performed, I claim,―
First. The process, substantially as herein-before described, of effecting
the fusion of iron ore, and the subsequent precipitation and conversion 1
of the iron therefrom for the production of iron and steel in separato
compartments of one and the same furnace.
Second. The use of furnaces for the manufacture of iron and steel
wherein a basin or receptacle is provided in one part of the furnace for
the fusion of the ore, and one or more other basins are provided at a 1
lower level in another part of the furnace into which the melted ore is
run from the first-named basin, in order there to be treated for the pre-
cipitation and conversion of the iron, substantially as herein-before
described with reference to the accompanying Drawings.
In witness whereof, I, the said Charles William Siemens, have here-
unto set my hand and seal, this Twenty-sixth day of March, in
the ycar of our Lord One thousand cight hundred and seventy-
three.
Witness,
JNO. A. HEAD,
3, Gt. George St.,
London,
S.W.
C. WILLIAM SIEMENS. (L.S.)