IMPROVEMENTS IN SMELTING METALLIC ORES, AND IN FURNACES TO BE EMPLOYED FOR THAT PURPOSE
Year: 1866

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 SMELTING METALLIC ORES, AND IN FURNACES TO BE
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
20th September 1866.
I, CHARLES WILLIAM SIEMENS, of No. 3, Great George Street, Westminster,
in the County of Middlesex, do hereby declare the nature of the said Inven-
tion for "IMPROVEMENTS IN SMELTING METALLIC ORES, AND IN FURNACES TO BE
EMPLOYED FOR THAT PURPOSE," to be as follows:-
In smelting iron ores the mineral is introduced at the top of a blast furnace
roughly mixed with carbonaceous material, such as coal, coke, or charcoal,
and with limestone or other fluxing materials, which latter combine with the
gang or stony ingredients naturally mixed with the ores, producing a fusible.

page_text: slag or cinder. Cast iron or pig metal is thus produced, which is tapped from
time to time into moulds at the foot of the furnace, and which is further
converted into wrought iron or steel by the processes of puddling and con-
verting, or directly into steel by the Bessemer process. Iron oxides have also
been converted directly into wrought iron mixing them intimately with
such a proportion of carbonaceous matter as suffices only to combine with the
oxygen contained in the ore, and by exposing the mixture in close chambers
or retorts to considerable heat. Or the reduction of the ore has been effected
in close heated retorts by passing a stream of hydrocarbon gas through the
same. By these latter processes spongy or pulverous malleable iron is
produced, which has been used in the manufacture of steel by mixing it with
carbonaceous matter, or by melting the mixture in pots or otherwise, or as a
chemical re-agent upon copper in solution.
My Invention has for its object the production of iron or steel directly from
the ore and in a continuous manner, analagous in this respect to the continuous
action of the blast furnace, and consists in exposing a mass of ore which may
or may not be mixed with reducing agents or fluxes upon an inclined surface
to the surface action of intense heat, and in introducing at the same time a
current or currents of combustible gases or of petroleum oil in amongst the
mass from below the inclined surface, so as to percolate through the mass
of ore, effecting or aiding in its reduction, and at the same time enveloping its
surface, where exposed to the flame, in a non-oxydizing or reducing atmos-
phere tending to facilitate its fusion. The fused metal and cinders accumulating
at the foot of the inclined surface are from time to time removed while a
mass of ore is maintained upon the inclined plane by its own gravitation,
fresh ore being supplied from hoppers at the top of the incline in regulated
quantities.
My Invention further consists in the construction of furnaces by which the
above described process may be carried into effect, the same being modi-
fications of the regenerative gas furnaces described in the Specification to
certain Letters Patent granted to Charles William and Frederick Siemens on
the 22nd of January 1861, No. 167, which improved form of furnace may
also be used with advantage for the fusion and reduction of copper and other
metallic ores, or the continuous fusion of solids generally. The arrangement
of furnace which I prefer to employ for this purpose consists of an oblong or
semicircular fire-brick chamber, two or three sides of which are formed as
inclined surfaces, which chamber is closed in at top by means of a fire-brick
arch, having openings provided with slides, through which the ore is introduced
on to the inclined surfaces. Small apertures are formed through the inclined

page_text: sides through which the combustible gases or liquid petroleum are introduced,
and in the end surface or surfaces of the furnace are formed other apertures.
which are in communication with the regenerators in such a manner that the
intensely heated gases from the regenerators pass in through one such aperture
and pass out through another. If requisite the current from the regenerators
may be intensified by the application of a blast.
In the bed of the furnace is formed a basin or recess into which the melted
metal flows, and from which it is removed through a tapping hole. A door
is also provided at the one end for stirring the molten metal or for introducing '
other substances, as hereafter described. One of the principal advantages
of this furnace is that the sides are protected against fusion by the ore or
other substance to be melted, particularly at the surface line of the liquid
cinders, where brick work is rapidly destroyed. It also affords easy access at
all sides for the introduction of tools and materials, and of the reducing gases.
or liquid at the sides. The admixtures of the iron ores depend upon its
constitution. It may or may not be calcined beforehand, but I always prefer
to crush and mix intimately the materials to be smelted. If pure oxides or
carbonates of iron are used no admixture whatever is required, for the gases
admitted at the sides suffice to effect its reduction and to supply the amount
of carbon necessary to produce natural cast steel, which will be of great purity
and excellent quality. The degree of carbonization or of hardness of the steel
produced depends upon the amount of reducing gas or liquid introduced, and
can be regulated at will according to the quality of samples taken from the
bath. The working of the furnace may, however, be facilitated by mixing
some carbon or coal dust, or granulated or divided cast iron, or spiegel eisen
with the ore. If the ore contains silica or alumina, an admixture of lime or
other alkaline substance will be necessary, but only in small proportions as
compared with the usual admixtures of these substances in blast furnaces,
because a higher point of fusion is admissable. If the ore or flux used
contains sulphur or phosphorus, an admixture of manganese (peroxide or
carbonate) will be desirable, unless it is preferred to desulphurize the molten
steel or iron in the bath of the furnace by admixture of ferro-manganese or
spiegel eisen. If a liberal supply of carbon is allowed cast iron will be the
result, which may be run off into pigs or may be used at once for foundry
purposes. If a sparing proportion of carbon or of reducing gases be applied
natural cast steel will be the result, which may from time to time be tapped
into a heated ladle, and thence run into moulds as usually practised. If the
reducing agents are applied still more sparingly, steely iron or pure malleable
iron may be produced. In this latter case the fluid metal in the bath should

page_text: be stirred after removal of the cinders and divided into balls, to be withdrawn
and hammered in the manner of puddling iron..
The gases used for the reduction of the ore may be conveniently produced
ool in the manner described in the Specification to certain Letters
be stirred after removal of the cinders and divided into balls, to be withdrawn
and hammered in the manner of puddling iron.
The gases used for the reduction of the ore may be conveniently produced
from coal in the manner described in the Specification to certain Letters
Patent granted to me and bearing date the 18th April 1863, No. 972.
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 20th March 1867.
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 Twentieth day of September, in the year of our Lord
One thousand eight hundred and sixty-six, in the thirtieth year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto
me, the said Charles William Siemens, Her special licence that I, the said
Charles William Siemens, my executors, administrators, 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, exercise, and vend, within the United Kingdom of
Great Britain and Ireland, the Channel Islands, and Isle of Man, an
Invention for "IMPROVEMENTS IN SMELTING METALLIC ORES, AND IN FURNACES TO
BE 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.
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, reference being had to the accompanying Sheet
of Drawings, and to the figures and letters marked thereon, that is to say:-
In smelting iron ores the mineral is introduced at the top of a blast

page_text: furnace, roughly mixed with carbonaceous material such as coal, coke, or
charcoal, and with limestone, or other fluxing materials, which latter combine
with the gang or stony ingredients naturally mixed with the ores, producing
a fusible slag or cinder. Cast iron or pig metal is thus produced, which is
tapped from time to time into moulds at the foot of the furnace, and which is
further converted into wrought iron or steel by the processes of puddling and
converting, or directly into steel by the Bessemer process. Iron oxides have
also been converted directly into wrought iron by mixing them intimately with
such a proportion of carbonaceous matter as suffices only to combine with the
oxygen contained in the ore, and by exposing the mixture in close chambers
or. retorts to considerable heat; or the reduction of the ore has been effected:
in close heated retorts by passing a stream of hydrocarbon gas through the same..
By these latter processes spongy or pulverous malleable iron is-produced
which has been used in the manufacture of steel by mixing it with carbo-
naceous matter, or by melting the mixture in pots or otherwise, or as a
chemical re-agent upon copper in solution; or wrought iron and steel are
produced directly from the ore by the Catelan forge, and other primitive pro-.
cesses employed in India and elsewhere, which by their nature are costly in
labor and materials, and cannot be carried out upon a large scale or in a
continuous manner.
My Invention has for its object the production of iron or steel directly from
the ore and in a continuous manner, analagous in this respect to the con-
tinuous action of the blast furnace, and consists in exposing a mass of ore,
which may or may not be mixed with reducing agents or fluxes; to the
surface action of intense beat produced by the combustion of highly-heated
air and gaseous fuel, and in introducing at the same time a current or cur-
rents of combustible gases or of petroleum oil or other volatile bydrocarbons,
alone or in combination with the combustible gases in amongst the mass of
ore from below the same, so as to percolate through the mass, effecting its.
reduction, and at the same time enveloping its surface where exposed to the.
flame in a non-oxidizing or reducing atmosphere, yielding a certain amount
of carbon tending to facilitate its fusion, the mass of ore being arranged in
such a manner, by preference upon inclined surfaces, that the fused metal
produced at the surface readily passes away therefrom so as to leave such.
surface always exposed to the action of the heat. The fused metal and slag
accumulating at the foot of the inclined surfaces of the ore are from time to
time removed, while a mass of ore is maintained upon the inclined surfaces
by its own gravitation, fresh ore being supplied from hoppers at the top of the
incline in regulated quantities, which hoppers receive sufficient heat from.

page_text: the furnace both by conduction and
the escape of heated gases upwards
to effect the partial reduction of the ores before they reach the heated
chamber.
My Invention further consists in the construction of furnaces by which the
above-described process may be carried into effect, the same being modifica-
tions of the regenerative gas furnaces described in the Specification to certain
Letters Patent granted to myself, in conjunction with Frederick Siemens, on
the 22nd of January 1861, No. 167, which improved form of furnace may also
be used with advantage for the fusion and reduction of copper and other
metallic ores. The arrangement of furnace which I prefer to employ for this
purpose consists of an oblong or polygonal fire-brick chamber, two or
more sides of which are formed as inclined surfaces, which chamber is
closed in at top means of a fire-brick arch having openings, which may
be provided with slides through which the ore is introduced on to the inclined
surfaces. Small apertures may be formed through the inclined sides through
which the combustible gases or liquid petroleum are introduced, or the gases
and liquid may be introduced through pipes inclining downwards upon the
inclined surfaces, and in the end or upper surface or surfaces of the furnace
are formed other apertures which are in communication with the regenerators
or other suitable heating apparatus in such a manner that the intensely
heated gases from the regenerators or other heating apparatus pass in through
one or several of such apertures, and pass out through another or others; if
requisite the current from the regenerators or heaters may be intensified by
the application of a blast.
In the bed of the furnace is formed a basin or sunken part into which the
molten metal flows, and from which it is removed through a tapping hole.
A door is also provided at the one end for stirring the molten metal or for
introducing other substances, as hereafter described, and for removing the
slag from time to time. One of the principal advantages of this furnace is, that
the sides are protected against fusion by the ore or other substance to be
melted, particularly at the surface line of the liquid cinders, where brick-
work is rapidly destroyed; it also affords easy access for the introduction of
tools and materials and of the reducing gases or liquid at the sides. The
admixture of the iron ore depends upon its constitution; it may or may not
be calcined beforehand, but I always prefer to crush and mix intimately the
materials to be smelted. If nearly pure oxides, such as hæmatite or magnetic
ore or roasted carbonates of iron are treated, I use no fluxing material
excepting a small per-centage of oxide or carbonate of manganese prepared
as hereafter described, which forms, with the earthy matter invariably asso-

page_text: metal of
ciated with the ores, sufficient slag for the protection of the molten metal,
the reduction of the ore being effected entirely by the hydrocarbon gas
penetrating the mass under the influence of intense superficial heat. The
degree of carbonization or of hardness of the steel or homogeneous iron
thus produced depends upon the amount of reducing gas (or liquid) intro-
duced, and can be regulated at will by means of supply valves according to
the quality of samples taken from the bath from time to time;
great purity and strength is thus produced which being tapped into ladles at
certain intervals of time may be poured into metal moulds and forged in the
usual manner. If the ore contains silica or alumina in considerable quantity
an admixture of lime or other alkaline substance will be necessary, but only
in small proportions as compared with the usual admixtures of these sub-
stances in blast furnaces, because a higher point of fusion is admissible. If
the ore or flux used contains sulphur, an admixture of manganese (peroxide
or carbonate) will be desirable, unless it is preferred to desulphurize the
molten steel or iron in the bath of the furnace by admixture of ferro-man-
ganese or spiegel eisen. In order to ensure the reduction of the oxide of
manganese, it is necessary that it should be mixed intimately with solid car-
bonaceous matter, for which purpose I saturate the same with a fat, oil, or
with molten pitch before mixing it with the ore; the fat, oil, or pitch parts
with its gaseous constituents at a comparatively low temperature, but a
residue of solid carbon remains in intimate connection with the particles of
oxide of manganese to effect its reduction, which takes place only at a com-
paratively high temperature. If a liberal supply of reducing gases is allowe:l,
or if, in addition to them, coal, coke, or bitumen is mixed with the ores, cast
iron will be the result, which may be run off into pigs, or may, be used at
once for foundry purposes. If a sparing proportion of reducing gases or oils
be applied natural cast steel will be the result, which should be tapped from
time to time into heated ladles and treated as before described; if the
reducing agents are applied still more sparingly malleable iron may be pro-
duced; in this latter case the fluid metal accumulating from time to time in
the bath should be stirred after removal of the slag, and divided into balls, to
be withdrawn and hammered in the manner of puddled iron. During the
operation of balling the supply of reducing gases should be nearly or entirely
stopped and the descent of the melting ores into the bath be prevented by the
introduction of slides into the mouths of the hoppers, and by checking the
temperature of the furnace.
The gases used for the reduction of the ore may be conveniently produced
from coal in the manner described in the Specification to certain Letters Patent

page_text: granted to me, and bearing date the 18th April 1863, No. 972, or they may
be taken from the same producers that supply the gaseous fuel to the furnace,
such as described in the Specification to my before-mentioned Patent, No. 167
of 1861, or the ordinary bydrocarbon gas produced in retorts may be em-
ployed for this purpose, either alone or in combination with liquid volatile
hydrocarbons, such as petroleum, as before mentioned. These reducing gases
should be cleansed of sulphurous acid and be forced in amongst the ore with
a certain moderate pressure, both of which objects are attained by passing
them down a vertical tube or column together with a shower of divided water,
or by forcing them by a steam jet and through a surface condenser where the
sulphurous acid, ammoniacal liquor, and other vapours will condense. The
advantages of employing these gaseous reducing agents instead of solid car
bonaceous matter are that all foreign and hurtful matter can be separated
beforehand, that it acts upon the entire mass of the ore uniformly, effecting its
entire reduction instead of allowing portions of the same to melt into slag
while overdosing other portions with carbon, as would be the case if coal or
other solid agents were employed. The hydrogen liberated from the carbon
of the gas is also likely to combine with phosphorus in the ore to be carried
off as phosphoretted hydrogen gas.
But in order that my Invention may be more thoroughly understood and
readily carried into effect, I will now proceed more particularly to describe the
best means I am acquainted with of performing the same.
Figures 1 to 4 on the accompanying Sheet of Drawings show the arrange-
ment of furnace which I prefer to employ. Figure 1 shows a transverse
section of the furnace on line I., II., Figure 2; Figure 2 shows a longitudinal
section on line III., IV., Figure 1; Figure 3 shows an end elevation of the
furnace and section through the gas and air passages on line V., VI., Figure 2 ;
and Figure 4 shows a side elevation of the furnace, and a longitudinal section
through the regenerators on line VII., VIII., Figure 1; similar letters of
reference indicate similar parts in each of the Figures.
The furnace consists of a chamber A enclosed at the top by a fire-brick
arch B, while the sides thereof are formed by inclined surfaces C, C, down
which the ore is caused to pass from the hoppers D, D. The bed E of the
furnace is made to incline from each side towards the centre, so as to form a
trough for the collection of the molten metal; and it is furthermore made to
incline longitudinally towards a tapping hole F in the one end wall of the
furnace. A door G is provided above this hole for the introduction of tools
for stirring the molten metal and of any substances to be mixed therewith, as
before mentioned; a similar door H is also provided at the other end of the

page_text: furnace for the removal of slag from time to time. Below the furnace are
arranged two sets of regenerators I, I, and I, I, for previously heating the
combustible gases and air required for producing the requisite heat in the
furnace by their combustion. The general arrangement and mode of opera-
tion of these regenerators is precisely the same as in those described in the
Specification to the before mentioned Letters Patent already granted to me
and Frederick Siemens, and they therefore require no further description
beyond this, that the atmospheric air is caused by means of the reversing
valve J to pass alternately from the chamber K into the regenerators I¹ and I',
while the combustible gases coming from gas producers through the passages
L, M, and pipe N, are caused by means of the reversing valve J¹ to pass
alternately into the regenerators I and I. The quantity of air and gas passing
in is regulated by means of the valves O, O', actuated by the levers and rods
P, P¹, so as to obtain a flame having the required properties in the furnace.
After passing through the one pair of regenerators, say, 11, 12, the highly
heated gas and air rise through the passages i¹, i, formed at the back of the
furnace and enter the latter simultaneously through the aperture Q, and there
produce an intense heat by their combustion. The hot gaseous products of
this combustion after doing duty in the furnace pass through the aperture Q¹
down the passages i³, i*, into the regenerators I³, I', and, after imparting their
heat to the same, escape through the reversing dampers O, O', into the flue R,
and thence into a powerful chimney. At the back of the sloping sides C, C,
of the furnace are two pipes S, S, communicating with the passage for
combustible gas L by means of the pipes U, and with the interior of the
furnace through the branches V passing through the inclined sides, as shown,
and opening in a downward direction. Through these branches consequently
carbonaceous gases are made to flow in from below among the mass of ore
passing in through the hoppers D in such quantities as to envelope the particles
thereof, as also the entire exposed surface in a reducing atmosphere, while at
the same time the surface of the ore is subjected to the action of the intense
heat produced, as above described, in the furnace; the ore is by this means
reduced to its metallic state, while the exposed surface thereof is at the same
time melted and flows down into the trough of the bed E. The pipes S are
provided furthermore with syphon branches W terminating in funnels, into
which, when a more carbonaceous gas is required than is supplied from the
producers, a volatile hydrocarbon, such as petroleum, is made to flow from
reservoirs through pipes X and regulating cocks x.
In order to impel the gas through the mass of ore and at the same time to
cleanse it from dust as well as from sulphurous acid and ammonia a jet of

page_text: steam is introduced at Y into the pipe U, from which pipe the combined gas
and steam are made to pass first into the surface condenser Z, enclosed in a
cold-water tank a, before entering the pipe T, so as to condense the whole of
the steam and cause the resulting liquid to pass down into the well b below,
whence it may be run into evaporating pans in order to recover its valuable
constituents.
Or in place of this arrangement for purifying the gas I employ that shown
in longitudinal and transverse sections at Figures 5 and 6, consisting of a long
chamber a into which the gas passes from the pipe U at bottom, and is made
to travel in a zig-zag direction over and in close contiguity with the par-
titions b, b, before issuing into the pipes T, T, while at the same time a stream
of water is made to flow in a contrary direction over the partitions b, entering
through the pipe c at top and escaping through the pipe d at bottom, carrying
off with it the condensible constituents of the gas. The ores with such ad-
mixtures of flux or reducing agents as may be thought necessary are filled
into the hoppers D from the platform e at intervals by the attendants, and as
a plenum of pressure is always maintained by the gases in the furnace, thus
causing a certain amount of gas to percolate upwards through the mass of
ore, heating and reducing the same preparatory to entering the furnace, and
then escaping from the hoppers; a hood f is constructed over the furnace with
hinged sides g so as to carry off such escaping gases. As the molten metal
accumulates in the bed of the furnace it is tapped off from time to time (say,
once every three hours), through the hole F, while the accumulating slag
is removed at more frequent intervals through the door H. Previous to
tapping the metal its quality is ascertained by removing and testing a sample.
If it should prove to be too poor in carbon spiegel eisen or pig metal may be
added to the bath to supply the deficiency; but if, on the other hand, the
sample should prove too rich in carbon, the supply of reducing gas is stopped
partially or wholly, the slag is removed, and the liquid metal stirred, or scrap
iron may be introduced. A number of these furnaces may be conveniently
erected in a row with a sunken railway in front to carry a heated ladle upon
wheels to receive the molten metal of either furnace in order to convey the
same to the ingot moulds placed between the rails.
Figures 7 to 9 show a modification of the furnace in which the molten
metal may either be tapped off in a liquid state, as in the previous arrange-
ment, or in which its conversion into malleable iron may at once be completed
by balling. Figure 7 shows a longitudinal section on line 1., II., Figure 9;
Figure 8 shows a transverse section on line III., IV., Figure 7; and Figure 9
shows a sectional plan on line V., VI., Figure 7. For this purpose the bed E

page_text: of the furnace A is made of the form usual for puddling furnaces. The heated
gases and air passing in alternately from one pair of the regenerators I³, 1', or
I, I, through the passages i¹, is, or i³, i, at each end escape, after under-
going combustion, at the opposite end into the other two regenerators, while
the carbonaceous gas for reducing the ore passes in from below the mass
through the pipe S, such gas being in this case entirely supplied by petroleum
or other liquid volatile hydrocarbon flowing from the tank X into the funnel-
mouthed end of the pipe S. The hopper D is provided with a slide T in order
when the operation of puddling is to be carried on (which is effected through
the door G) to cut off the supply of ore when the required quantity of the
molten metal has accumulated on the bed. An open pan U is formed beneath
the bed of the furnace, which is filled with water up to the overflow pipe u
in order to cool the bed plate of the furnace through radiation and also by
evaporation, a current of air being established over it by upcast brick channels.;
The ore used in this case should be hæmatite or other iron oxide without
much foreign substance; it should be pulverized and mixed intimately with
from five to ten per cent. of pitch and manganese previously melted together
and crushed when cold. In melting the materials a most intense heat has to
be maintained in the furnace, and when a sufficient quantity of molten metal
has collected in the bath the supply of volatile oil (or gas) is stopped, the
regulating damper in the hopper is partially or wholly closed, and the heat
moderated, while the metal in the bath is stirred about and formed into balls
to be brought under the forge hammer.
Figures 10 and 11 show an arrangement of the furnace particularly
adapted for producing cast iron of superior purity and toughness in large
quantities. Figure 10 shows a transverse section on the line I., II., Figure 11,
and Figure 11 shows a longitudinal section on line III., IV., Figure 10. The
general form of the furnace A, bed E, inclined sides C, and hoppers D for the.
introduction of the ore is similar to that of the arrangement shown in Figures
1 to 4. Instead however of the system of regenerators there shown I omit
the regenerators for heating the combustible gases, and I introduce the air in
the shape of a hot blast heated either in a regenerator with reversed currents
or in an ordinary hot blast stove by the hot products of combustion from the
furnace. For this purpose a chamber N is formed over the arch B of the
furnace, into which the combustible gases from the producers pass from the
pipe M, and whence they enter the furnace through the openings Q. The hot
blast is conducted from the stove I through the pipe K and issues through the
nozzles together with the combustible gas through the openings Q into the
furnace; here the requisite beat is produced by the combustion of the gas

page_text: and air (which heat need not be so intense as in the case of producing steel
or malleable iron) while at the same time hydrocarbon gas in considerable
quantities is introduced through the pipes S and branches V beneath the mass
of ore introduced through the hoppers D from the upper platform so as to
effect their reduction. The ore used in this apparatus is supposed to be less
pure than that in the furnaces before described, and the temperature being
also less a considerable admixture of lime or other fluxing material will be
requisite. To this may be added a considerable per-centage of common
gaseous coal (containing as little sulphur as possible) in order to assist the
reduction of the ore in the hoppers and the carbonisation of the metal in the
furnace. The molten metal accumulates on the bed of the furnace, whence
it is run off as required through the tapping hole F, the slag being removed
from time to time through the door G. The hot products of combustion
ascend in part through the ore in the hoppers, but are for the most part caused
to escape through the passage Q¹ into the stove I in order to impart their heat
to the blast which is only required to be a mild fan blast to force the products
of combustion through the ore in the hoppers and through the stoves.
pipe K for the hot blast is provided with openings k at top furnished with
covers through which access may be gained to the nozzles k for the purpose of
changing them.
The
Having now described the nature of my Invention, and in what manner the
same is to be performed, I wish it to be understood that I do not limit myself
to the precise arrangements of furnaces for carrying my Invention into
practice as herein-before described with reference to the accompanying
Drawings, as it will be evident that these may be variously modified without
departing from the nature of my Invention, but what I claim is,-
First, producing cast steel and iron directly from the ore by exposing the
ore in a more or less finely divided state to the surface action of intense heat
while regulated currents of rich hydrocarbons or carbonaceous gases percolate
through the mass of ore in a transverse direction towards the heated surface,
effecting its reduction and carbonisation and enveloping the melting surface
of the mass in an atmosphere of reducing gases or flame so as to prevent the
re-oxydation of the reduced metal.
Second, the application for effecting the reduction of metallic ore into steel
or iron under the influence of intense surface heat of regulated streams of
petroleum or other volatile mineral oils, either by themselves or in combination
with forced currents of permanent carbonaceous gases traversing the mass of
ore under operation.
Third, rendering the simultaneous reduction and fusion of iron ores effected

page_text: by means of intense surface heat and regulated currents of reducing gases or
vapours passing through them continuous, by supplying the ore by gravitation
so as to maintain the mass of ore upon the sides of the reducing chamber in
proportion as it is converted and fused.
Fourth, arranging the chamber in which the simultaneous reduction and
fusion of the steel or iron is effected in such a manner that the ore descends
through hoppers or shafts upon the sides of the chamber so as to protect the
walls or inclined surfaces thereof from the heat of the furnace and the
corrosive action of the slags or cinders of the metallic bath by the interposition
of the ore itself, substantially as described with reference to the accompanying
Drawings.
Fifth, the arrangement of gas furnaces for producing the intense surface
heat required in-effecting the simultaneous and continuous reduction of iron
ores into cast steel or iron substantially as herein-before described with
reference to the accompanying Drawings.
In witness whereof, I, the said Charles William Siemens, have hereunto
set my hand and seal, this Twentieth day of March, in the year of our
Lord One thousand eight hundred and sixty-seven.
0 Witness,
J. A. HEAD,
3, Great George St.,
Westminster, S. W.
C. W. SIEMENS. (L.S.)