IMPROVEMENTS IN TREATING IRON ORES, AND IN PROCESSES AND APPARATUS FOR THE PRODUCTION OF CAST STEEL WHERE SUCH ORES ARE EMPLOYED
Year: 1870

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 TREATING IRON ORES, AND IN PROCESSES AND
APPARATUS FOR THE PRODUCTION OF CAST STEEL WHERE SUCH ORES ARE
EMPLOYED."
Scaled the 3rd May 1870, and dated the 28th February 1870.
PROVISIONAL SPECIFICATION left by the said Charles William Siemens
at the Office of the Commissioners of Patents, with his Petition,
on the 28th February 1870.
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 TREATING: IRON ORES, AND IN
PROCESSES AND APPARATUSES FOR THE PRODUCTION OF CAST STEEL WHERE SUCH ORES
ARE EMPLOYED," to be as follows:-
:-
In my Patent of 1866, No. 2413, I described a process and apparatus
for the production of cast steel directly from the ore with or without the
A

page_text: addition of pig iron and of ferro-manganese or spiegelisen. This process
consisted essentially in effecting the reduction or deoxidation of the ore
by the reaction upon it of carbonaceous matter under the influence of
intense furnace heat, and in effecting the liquefaction of the reduced
ore within the same furnace by the further addition of carbonaceous
matter. It was found, however, in practice that the deoxidation of the
cre and the adjustment of the chemical condition of the metallic bath
was attended with great difficulty under those circumstances, to remove
which I subsequently separated the process of deoxidising the ore from
that of effecting its liquifaction and chemical adjustment by the intro-
duction of vertical or other retorts or of rotating muffles, as described in
my Patents of the 21st August 1867, No. 2395,-and-of-the-10-June-
1868, No. 1892, respectively.
Notwithstanding these improvements it was difficult to realize all the
conditions necessary to insure a satisfactory result. The reduction of
iron ore in close retorts or muffles is essentially a slow and expensive
process, and the pulverulent iron produced thereby upon being introduced
into the melting furnace floats upon the metallic bath for a considerable
length of time without being incorporated with it, being exposed in the.
ineantime to the oxidizing and sulphurizing action of the flame; the
metallic oxide thus produced corrodes the banks of the metal bath, and
being a non-conductor of heat causes the fluid metal below to set.
According to my present Invention cast steel is produced by the
concerted action of two separate processes, the one serving to convert
the raw ore into lumps or loaves of calcined, fluxed, and partially
deoxidized material, and the other to smelt and convert this material
with or without the addition of pig metal into cast steel of any desired
temper. The first or preparatory process is carried on in a furnace (by
preference a regenerative gas furnace) resembling in form a copper
smelter's or large puddling furnace, baving charging doors at the sides
or in the roof and a door in front for withdrawing the smelted material
into pig beds or moulds. This latter door has its sill plate on a level
with the bed of the furnace, but has false sills or bricks placed upon it
for retaining the fluid material in the furnace until the completion of
the operation, when this false sill or the bricks are removed, and the.
semi-fluid contents of the furnace are raked forward into moulds arranged
in front of the furnace. The bed and sides of the furnace are made
conveniently of alluminious bricks resting upon iron plates, but refractory

page_text: iron ore, such as haematite, may be used with advantage in repairing the
sides from time to time.
The chemical operation performed in this furnace is as follows:-,
The ore to be operated upon, which I will suppose to be haematite ore.
containing 10 per cent. of silica, being crushed to the extent that no
pieces exceed the size of walnuts or apples, is mixed with about 5 per
ccnt. of crushed limestone (or with other fluxing material) and with
about 3 per cent. of small coke or anthracite. A ton (or other
quantity) of this batch being prepared the furnace is heated to whiteness.
and is charged first with about 1 cwt. of light coke, such as gas coke or
charcoal, spread uniformly over the bottom, whereupon the batch is
introduced and spread also uniformly over the bed. of the furnace.
The furnace doors are thereupon closed and a good welding heat is
maintained for three or four hours. By the reaction under the influence.
of heat of the 3 per cent. of carbon mixed with the ore the peroxide of iron
of which it consists is converted into fusible magnetic oxide, while the
silica which it contains combines with the limestone, forming a fusible
slag. This action commences at the surface and extends downwards
until the layer of carbon is reached, when a further reaction upon the
fluid ore (accompanied by ebullition) ensues, resulting in its partial
deoxidation. Before the boiling has quite ceased the mass is stirred,.
and on the barrier on the sill of the tapping door being removed the
semi-fluid mass partially flows and is partially raked forward into the
moulds. Previous to discharging the furnace these moulds have been-
charged first with a layer of debris of partially reduced ore from previous.
operations, and next with hard carbonaceous matter, such as coke or
charcoal, amounting to from 5 to 10 per cent. by weight of the ore-
charged into the furnace. The fluid portion of the mass discharged from
the furnace fills the interstices of the coke and debris and binds the
whole together into lumps or loaves ready for use in the smelting.
furnace, but owing to a reaction between the heated oxides or cinder
and the imprisoned coke a furthe deoxidation of the latter is effected.
within the moulds, or within the heated chamber near the melting furnace,
to be presently described, where the loaves should be kept in a reducing
atmosphere until they are actually required. The process of decar-.
burization of these loaves may thus be carried to a greater or less
degree of completion according to the per-centage of carbon employed,
and according to the time of exposure to heat in a reducing atmosphere.
.
^ 2

page_text: If the available reducing agent is binding coal containing only a small
per-centage of sulphur the operation of the preparatory furnace may be
varied by mixing the crushed ore and flux with from 12 to 16 per cent.
of crushed coal (according to the degree of deoxidation or carborization
required) and by charging this mixture on to the furnace bed after it has
been divided into compartments by putting flat iron or steel bars on
edge or by means of bricks or slabs of fire-clay put on edge; if iron or
steel bars are used the thickness of mixed ore charged should exceed
the height of the bars in order to cover them completely and save them
from oxydation: Heat being applied for several hours the mixture will
have formed into partially or wholly deoxidised lumps.or_loaves,-which-
may be used in the melting furnace instead of the lumps produced by
fusion of the ores. Or the mode of producing these lumps may be
varied by forcing the mixed ore into moulds and by exposing the con-
solidated bricks or lumps to furnace heat in order to effect the deoxida-
tion of the ore.
The steel melting furnace employed is similar to the furnace described
in my Patent No. 1892 of 1868, except that the air and gas are mixed
differently, that the furnace bottom is prepared in a manner to be
described herein-after, and that the furnace is provided with a charging
chamber at the back. A steel melting heat having been reached in this
furnace pig metal is charged to form a metallic bath, when the loaves or
lumps from the preparatory furnace before described are introduced into
the charging chamber, and are successively pushed forward into the
melting furnace in order to become fused or incorporated with the
metallic bath. These loaves, consisting partly of deoxidized iron and
partly of oxides, will by virtue of their gravity sink to some extent
below the surface of the liquid bath of the melting furnace and will
cause an active ebullition (resulting from the reaction between the oxide
and the carbon of the fluid metal), which ebullition in causing inter-
mixture promotes the dissolution of the loaves and the decarburization
of the liquid bath to the requisite degree; this degree is ascertained by
taking samples of the metal from time to time, which when chilled
in water and broken with a hammer should no longer break short but
should show considerable toughness and a fractured surface of honey-
combed and silky appearance. Metal presenting this appearance
contains from 1 to 1.5 per cent. of carbon, and in adding spiegeleisen to
the bath the per-centage of carbon may be increased to the extent
·

page_text: required for producing the desired temper, while at the same time
manganese is introduced which is necessary to prevent red shortness.
Before adding the spiegeleisen either in the solid or liquid form it is
necessary to stir the metallic bath well with an iron hook or rake, which
operation is accompanied by an active or even violent ebullition. Care
must also be taken that the cinder covering the metallic bath never
exceeds one or two inches in thickness, that it is always liquid, and that
it presents when cooled and broken a glossy light brown appearance.
If the slag should during the operation of melting the loaves accumulate
to a greater thickness it is removed by skimming or discharging it over
the sill plate of the front door of the furnace, which latter may be raised
or lowered by placing upon it or removing loose iron packing bars. If
the cool and fractured slag presents a dark or crystalline appearance
time must be given for its clearance, which will be accellerated by stirring
the bath. The ladle, skulls, and scrap from previous meltings may
also be re-introduced into the furnace before the spiegeleisen is added.
Or pulverulent iron produced by other processes may be introduced in
addition to the loaves herein-before described. The process may be
varied between wide limits according to the relative abundance and
quality of the materials used. If pig metal of sufficient purity from
sulphur and phosphorus can be had in abundance and rich or pure ore
is scarce or expensive, it will be advantageous to deoxidize the ore only
partially in the preparatory furnace in order that it may retain the power
of decarbonizing two or three times its own weight of pig metal in the
melting furnace, whereas if rich ore, which may be haematite or spathic
ore or clay, ironstone, or a mixture of several, is cheap as compared
with haematite or other good description of pig metal, the deoxidation
of the ore should be carried further in the preparatory process by adding
a larger proportion of carbon in the preparatory furnace or in the
moulds.
Although the use of pig metal in forming the primary bath in the
melting furnace and the use of spiegeleisen in completing the operation
are extremely convenient where suitable metals can be obtained at a
of these mex be entirely disnensed

page_text: ·bonized compound of the ores of iron and manganese. In working
solely with these deoxidized and carbonized ores the bed of the melting
furnace is first covered with a layer of coke, charcoal, or anthracite, upon
which the highly carbonized loaves first mentioned are charged in a
heated condition, which in melting will form a metallic bath covered
with cinder and form a foundation for the after operation. Instead of
using any haematite ores in these processes, I prefer to mix the same
with argilaceous or spathic ores in such proportions that the gangue of
both ores forms a fusible slag, whereby the use of lime is avoided.
Titanic sand may also be used with advantage.
The success of this process depends greatly-upon-the-formation of a
_sound_furnace-bottom-in the melting furnace. Sand or a mixture of
sands has hitherto been mostly employed to form such bottoms, but-
these frequently melt or rise in large masses to the surface of the metal
bath, in which case the thickness of the slag is greatly increased and the
metal frequently "sets" in the deepened bottom of the furnace. These
difficulties are in a great measure avoided by forming the furnace bottom
in the following manner :-Pure siliceous sand is obtained, which is
backed in order to destroy any organic matter that may be mixed with it
and is passed through a sieve' in order to separate lumps or foreign
matter; if the sand contains iron or lime it is first of all washed with
muriatic or other acid. One hundred parts of this purified dry sand
are mixed intimately with about 3 per cent. of fine glass powder by
passing both powders together through a sieve, and the mixture is put
aside for use. In making a new bottom the iron plated furnace bottom is
first covered with bricks and the heat of the furnace is raised to whiteness.
A layer of the dry mixture of sand and glass powder is thereupon spread
over the brick bottom to the thickness of about 2 inches, after which
time is allowed until the surface has commenced to harden in con-
sequence of the particles of glass melting and thus binding adjacent
particles of the white sand together without being sufficient in quantity
to fuse them. Another and somewhat thinner layer of the dry powder
is next applied and the heat is raised so as to produce a more complete
fusion of the glass powder, and consequently a greater degree of hardness
and cohesion of the mass. A still thinner layer of the mixture is then
applied, and this process is repeated until a bottom of the requisite form
and thickness is obtained. The furnace doors are thereupon thrown
open and the admission of gas, and air from the regenerators is reduced.

page_text: in order to allow the bottom to set hard, when it is ready for receiving
its charge of pig metal and reduced ore. The same method of charging
the dry mixture is resorted to for mending the bottom between charges.
The melting: furnace which I employ is as before stated similar t>
those I have described in my former Patents, but I improve the arrange.
ment for mixing the heated combustible gases and the heated air
arising from the regenerators by raising the vertical air ports very nearly
to the roof of the furnace, and by bringing, the side walls of the flues
forward towards the heated chamber in a convergent manner until they
meet. By this arrangement the gas is introduced into the heate
chamber below the air through channels increasing in width towards the
furnace, where it is met by the air passing in divers directions effecting
its thorough combustion while traversing the heated chamber, the
uncombined air being at the same time prevented from coming into
contact with the metal in the bed of the furnace.
In arranging steel works I place several melting furnaces side by side
with their fronts or tapping holes facing the foundry, or I place two
such rows opposite each other with the foundry between them. From.
cach centre of the furnace or tapping hole a trench extends at right
angles to the line of furnaces into a wider and deeper trench running
through the middle of the foundry parallel with the line of furnaces. A
line of rails is laid upon the edges of the cross trenches and across the
central trench upon girders, which line of rails carries the ladle carriages,
by which a ladle when suitably lined and heated may be drawn close up
to the tapping hole to receive a charge of steel and be moved by a wheel
and pinion or other agency over the central trench; a line of rails at the
bottom of this. latter carries suitable trucks upon which the moulds to
receive the fluid metal are arranged; these mould. trucks may be con.
veniently moved to and fro by an endless travelling chain passing ove:
pullies at the bottom of the pit and being actuated by means of a small
winding engine fitted with reversing. gear. By opening the stopper in
the bottom of the ladle these moulds are filled and the truck upon
which they are mounted is. moved out of the foundry to a crane or into
an annealing stove if the castings are not to be hammered or rolled.
By this general arrangement the preparation of the moulds and the
removal of the cast ingots or castings is greatly facilitated.

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 27th August 1870.
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 February, in the
year of our Lord One thousand eight hundred and seventy, in the
thirty-third 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, admi-
nistrators, 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
Ircland, the Channel Islands, and Isle of Man, an Invention for "IM-
PROVEMENTS IN TREATING IRON ORES, AND IN PROCESSES AND APPARATUSES FOR THE
PRODUCTION OF CAST STEEL WHERE SUCH ORES ARE EMPLOYED," 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
Drawings, and to the figures and letters marked thereon, that is to
say:
In my Patent of 1866, No. 2413, I described a process and apparatus
for the production of cast steel directly from the ore with or without the
addition of pig iron and of ferro-manganese or spiegeleisen. This
process consisted, essentially in effecting the reduction or deoxydation

page_text: of the ore by the reaction upon it of carbonaceous matter under the
influence of intense furnace heat, and in effecting the liquifaction of the
reduced ore within the same furnace by the further addition of car-
bonaccous matter. It was found, however, in practice that the deoxidation
of the ore and the adjustment of the chemical condition of the metallic
bath was attended with great difficulty under those circumstances, to
remove which I subsequently separated the process of deoxidizing the ore
from that of effecting its liquifaction and chemical adjustment by the
introduction of vertical or other retorts or of rotating muffles, as described
in my Patents of the 21st August 1867, No. 2395, and of the 10th June
1868, No. 1892, respectively.
Notwithstanding these improvements it was difficult to realize all the
conditions necessary to insure a satisfactory result. The reduction of
iron ore in close retorts or muffles is essentially a slow and expensive
process, and the pulverulent iron produced thereby upon being introduced
into the melting furnace floats upon the metallic bath for a considerable
length of time without being incorporated with it, being exposed in the
meantime to the oxidizing and sulphurizing action of the flame; the
metallic oxide thus produced corrodes the banks of the metal bath, and
being a non-conductor of heat causes the fluid metal below to set.
According to my present Invention cast steel is produced by the
concerted action of two separate processes, the one serving to convert the
raw ore into lumps or loaves of calcined, fluxed, and partially deoxidized
material, and the other to smelt and convert this material with or
without the addition of pig metal into cast steel of any desired temper.
The first or preparatory process is carried on in a furnace (by preference
a regenerative gas furnace) resembling in form a copper smelter's or
large puddling furnace having charging doors at the sides or in the roofs
and a door in front for withdrawing the smelted material into pig beds
or moulds. This latter door, according to one arrangement, has its sill
plate on a level with the bed of the furnace, but has false sills or bricks
placed upon it for retaining the fluid material in the furnace until the
completion of the operation, when this false sill or the bricks are removed
and the semi-fluid contents of the furnace are raked forward into moulds
arranged in front of the furnace. Or stoppered discharging apertures
may be formed below the ordinary doors of the furnace. The bed and
sides of the furnace are made conveniently of aluminious bricks resting

page_text: upon iron plates, but refractory iron ore such as haematite may be used
with advantage in repairing the sides from time to time..
The chemical operation performed in this furnace according to one
arrangement is as follows:-The ore to be operated upon, which I will
suppose to be haematite ore containing 10 per cent. of silica, being
crushed to the extent that no pieces exceed the size of walnuts or apples,
is mixed with about five per cent. of crushed limestone (or with other
fluxing material) and with about 3 per cent. of small coke or anthracite.
A ton (or other quantity) of this batch being prepared the furnace is
heated to whiteness and charged first with about 1 cwt. of light coke,
such as gas coke or charcoal, spread uniformly-over-the-bottom, where-
upon the batch is introduced and spread also uniformly over the bed of
the furnace. The furnace doors are thereupon closed, and a good weld-
ing heat is maintained for three or four hours by the reaction under the
influence of heat of the three per cent. of carbon mixed with the ore, the
peroxide of iron of which it consists is converted into fusible magnetic
oxide, while the silica which it contains combines with the limestone,
forming a fusible slag. This action commences at the surface and
extends downwards until the layer of carbon is reached, when a further
reaction upon the fluid ore (accompanied by cbullition) ensues resulting
in its partial deoxidation. Before the boiling has quite ceased the mass
is stirred, and on the barrier on the sill of the tapping door being
removed the semi-fluid mass partially flows and is partially raked forward
into the moulds. Previous to discharging the furnace these moulds have
been charged first with a layer of debris of partially reduced ore from
previous operations and next with hard carbonaceous matter, such as.
coke or charcoal, amounting to from 5 to 10 per cent. by weight of the
ore charged into the furnace. The fluid portion of the mass discharged
from the furnace fills the interstices of the coke and debris and binds
the whole together into lumps or loaves ready for use in the smelting
furnace, but owing to a reaction between the heated oxides or cinder and
the imprisoned coke a further deoxidation of the latter is effected within
the moulds or within a heated chamber or hot store furnace near the
melting furnace to be presently described, where the loaves should be
kept in a reducing atmosphere until they are actually required. The a
process of deoxidation of these loaves may thus be carried to a greater or
less degree of completion according to the per-centage of carbon employed
and according to the time of exposure to heat in a reducing atmosphere:

page_text: If the available reducing agent is binding coal containing only a
small per-centage of sulphur, the operation of the preparatory furnace
may be varied by mixing the crushed ore and flux with from 12 to 16
per cent. of crushed coal (according to the degree of deoxidation or
carburization required) and by charging this mixture into the furnace
cither continuously or in batches, the bed of the furnace being in
some cases divided into compartments by putting flat iron or steel
bars on edge, or by means of bricks or slabs of fire-clay put on edge.
If iron or steel bars are used the thickness of mixed ore charged should
exceed the height of the bars in order to cover them completely and
save them from oxidation. Heat being applied for several hours the
mixture will have formed into partially or wholly deoxydized lumps or
loaves, which may be used in the melting furnace instead of the lumps
produced by fusion of the orcs. Or the mode of producing these lumps
may be varied by forcing the ore mixed with fluxing materials and
binding coal into moulds, and by exposing the consolidated bricks or
lumps to furnace heat in a closed heated chamber or hot store furnace
such as before mentioned in order to effect the deoxidation of the orc.
The steel melting furnace employed is similar to the furnace described in
my Patent, No. 1892 of 1868, except that the air and gas are mixed
differently, that the furnace bottom is prepared in a manner to be
described herein-after, and that the furnace is provided with a charging
chamber at the back. A steel melting heat having been reached in
this furnace pig metal is charged to form a metallic bath, when the
loaves or lumps from the preparatory furnace before described arc
introduced into the charging chamber, and are successively pushed
forward into the melting furnace in order to become fused or incor-
porated with the metallic bath. These loaves, consisting partly of de-
oxidized iron and partly of oxides, will by virtue of their gravity sink
to some extent below the surface of the liquid. bath of the melting
furnace, and will cause an active ebullition (resulting from the reaction
between the oxide and the carbon of the fluid metal), which ebullition
in causing intermixture promotes the dissolution of the loaves and the
decarburization of the liquid bath to the requisite degree. This degree
is ascertained by taking samples of the metal from time to time, which
when chilled in water and broken with a hammer should no longer
break short, but should show considerable toughness and a fractured
surface of honeycombed and silky appearance.
Metal presenting
this appearance contains from 0.1 to 0.15 per cent of carbon, and in

page_text: adding spiegeleisen to the bath the per-centage of carbon may be
increased to the extent required for producing the desired temper, while
at the same time manganese is introduced which is necessary to prevent
red shortness. Or in place of using spiegeleisen the requisite carbon
and manganese may be introduced in the form of lumps made as
herein-after described. Before adding the spiegeleisen either in the
solid or liquid form, or the lumps of reduced ore containing manganese
it is necessary to stir the metallic bath well with an iron hook or rake,
which operation is accompanied by an active or even violent ebullition.
Care must also be taken that the cinder covering the metallic bath
never exceeds one or two inches in thickness, that it is always
liquid, and that it-presents when cooled and broken a glossy light.
brown appearance. If the slag should during the operation of melting
the loaves accumulate to a greater thickness it is removed by skimming
or discharging it over the sill plate of the front door of the furnace,
which latter may be raised or lowered by placing upon it or removing
loose iron packing bars. If the cool and fractured slag presents a
dark or crystalline appearance time must be given for its clearance
which will be accelerated by stirring the bath; should the metal become
too soft before the slag is sufficiently clean it is necessary to add small
quantities of pig iron. The ladle skulls and scrap from previous
meltings may also be reintroduced into the furnace before the spiegel-
eisen is added, or pulverulent iron produced by other processes may be
introduced. in addition to the loaves herein-before described: The
process may be varied between wide limits according to the relative
abundance and quality of the materials used. If pig metal of suffi-
cient purity from sulphur and phosphorus can be had in abundance,
and rich or pure ore is scarce or expensive, it will be advantageous. to
deoxidize the ore only partially in the preparatory furnace, in order
that it may retain the power of decarburizing two or three times its
own weight of pig metal in the melting furnace, whereas if rich ore
(which may
be haematite or spathic ore, or clay, ironstone, or a mixture
of several) is cheap as compared with haematite or other good descrip-
tion of pig metal, the deoxidation of the ore should be carried further
in the preparatory process by adding a larger proportion of carbon in the
preparatory furnace or in the moulds.
Although the use of pig metal in forming the primary bath in the

page_text: tion are extremely convenient where those metals of a suitable quality
can be obtained at a reasonable cost, yet both or either of these may be
entirely dispensed with. In this case three descriptions of lumps or
loaves of deoxidized orc should be used, the first containing a consider-
able excess of carbon beyond what is necessary for its mere reduction,
the second being of the nature and proportions before described, and the
third being again a highly carburized compound of the ores of iron and
manganese which may be made in the following manner :-Ore rich in
manganese, titanium, or other oxidizable metal intended to be incorpo-1.
rated with the bath is crushed and well mixed with crushed dry clay
and binding coal free from sulphur in the proportions of about 100 parts:
by weight of ore, 25 parts of coal, and 10 parts of clay. This compound
is then sprinkled with water and mixed till it barely binds in the hand,:
after which it is filled into moulds and consolidated by pressure as
before described with reference to ordinary iron ore. These lumps or
bricks are stacked in a hot place (over a furnace) for, say, two days, and
are then charged into the before-mentioned heated chamber or hot
store furnace; where they are kept for 24 hours or more, and whence they
are taken in a hot state to be charged into the bath of the steel melting
furnace towards the end of the operation. In working solely with these
deoxydized and carburized ores the bed of the melting furnace is first.
covered with a layer of coke, charcoal, or anthracite upon which the
highly curburized loaves first mentioned are charged in a heated con-
dition, which in melting will form a metallic bath covered with cinder,
and form a foundation for the after operation. Instead of using any
hacmatite ores in these processes I prefer to mix the same with argil-
lacious or spathic ores in such proportions that the gangue of both ores.
forms a fusible slag whereby the use of lime is avoided. Titanic iron
sand may also be used with advantage. The success of this process
depends greatly upon the formation of a sound furnace bottom in the
melting furnace. Sand, or a mixture of sands, has hitherto been mostly
employed to form such bottoms, but these frequently melt or rise in
large masses to the surface of the metal bath, in which case the thick-
ness of the slag is greatly increased and the metal frequently "sets" in
the deepened bottom of the furnace. These difficulties are in a great
measure avoided by forming the furnace bottom in the following manner:-
Pure silicious sand is obtained, which is baked in order to destroy any
organic matter that may be mixed with it, and is passed through a sieve
in order to separate lumps or foreign matter; if the sand contains iron.

page_text: -
or lime it is first of all washed with muriatic or other acid, one hundred
parts of this purified dry sand are mixed intimately with about 3 per
cent. of fine glass powder by passing both together through a sieve and
the mixture is put aside for use. In making a new bottom the iron.
plated furnace bottom is first covered with bricks, and the heat of the
furnace is raised to whiteness. A layer of the dry mixture of sand and
glass powder is thereupon spread over the brick bottom to the thickness
of about 2 inches, after which time is allowed until the surface has
commenced to harden in consequence of the particles of glass melting and
thus binding adjacent particles of the white sand together without being
sufficient in quantity to fuse them. Another and somewhat-thinner layer
of the dry powder-is-next-applied and the heat is raised so as to produce
a more complete fusion of the glass powder and consequently a greater
degree of hardness and cohesion of the mass. A still thinner layer of
the mixture is then applied, and this process is repeated until a bottom
of the requisite form and thickness is obtained. The furnace doors are
thereupon thrown open and the admission of gas and air from the
regenerators is reduced in order to allow the bottom to set hard, when it
is ready for receiving its charge of pig metal and reduced ore.
The same
method of charging the dry mixture is resorted to for mending the
bottom between the charges.
. The melting furnace which I employ is as before stated similar to
those I have described in my former Patents, but I improve the arrange-
ment for mixing the heated combustible gases and the heated air arising
from the regenerators by raising the vertical air ports very nearly to the
roof of the furnace and by bringing the side walls of the flues forward
towards the licated chamber in a convergent manner until they meet.
By this arrangement the gas is introduced into the heated chamber
below the air through channels increasing in width towards the furnace
where it is met by the air passing in in diverse directions effecting its
thorough combustion while traversing the heated chamber, the un-
combined air being at the same time prevented from coming into contact
with the metal in the bed of the furnace. In arranging steel works I
place several melting furnaces side by side with the fronts or tapping
holes facing the foundry, or I place two such rows opposite to each
other with the foundry between them. From each centre of the furnace
or tapping hole a trench extends at right angles to the line of furnaces
into a wider and deeper trench running through the middle of the

page_text: .
foundry parallel with the line of furnaces. A line of rails is laid upon
the edges of the cross trenches and across the central trench upon girders,
which line of rails carries the ladle carriages, by which a ladle when
suitably lined and heated may be drawn close up to the tapping hole to
receive a charge of-steel and be moved by a wheel and pinion or other
agency over the central trench. A line of rails at the bottom of this
latter carries trucks upon which the moulds to receive the fluid metal
are arranged. These mould trucks may be couveniently moved to and
fro by an endless travelling chain passing over pulleys at the bottom of
the pit and being actuated by means of a small winding engine fitted
with reversing gear. By opening the stopper in the bottom of the ladle
these moulds are filled and the truck upon which they are mounted is
moved out of the foundry to a crane or into an annealing stove if the
castings are not to be hammered or rolled. By this general arrange-
ment the preparation of the moulds and the removal of the cast ingots
or castings is greatly facilitated.
Having thus described the nature of my Invention, and in what
manner the same is to be performed, I will now proceed more parti-
cularly to describe the arrangement of furnaces which I prefer to employ
for carrying out the the before-described processes, for which purpose I
shall refer to the accompanying Drawings.
1
Figure 1, Sheet I., shows sectional elevations respectively of the
preparatory furnace at X for preparing the lumps or loaves as before
described, the heated chamber or hot store furnace at Y for maintaining
the lumps or loaves in a heated reducing atmosphere until required for
conversion in the steel melting furnace at Z. The construction of each
of these furnaces is shown more clearly to an enlarged scale in Figures 2
to 10; Figure 2 shows a longitudinal section of the preparatory furnace
on line 2, 2, Figure 4; Figure 3 shows a transverse section of the same
on line 3, 3, Figure 2; and Figure 4 shows a sectional plan on line 4-4,
Figure 2.
In this furnace the crushed ore A, A, mixed with the
requisite per-centage of flux and carbonaceous matter as before described
is fed continuously on to the bed B through the hopper C, into which
it is charged from trucks W running on rails as shewn at Figure 1.
The ore is caused to pass gradually from the hopper in a thick layer
down the inclined side D of the furnace situated opposite the gas and air
ports, which are all placed on one and the same side of the furnace in a
similar manner to arrangements already patented by me. The bed B
'

page_text: and inclined side D of the furnace are constructed of strong metal
plates b, d, covered with fire-brick b', d', the plates being entirely open
to the air so as to be kept cool, and a current of air is furthermore in-
duced for this purpose below the bed by the formation of a chimney flue E
passing through the partition wall E¹ between the two sets of gas and
air passages F, G, F, G, and communicating with a chimney E above
the furnace, as shown. The bed of the furnace is enclosed on the
inner side by means of a water bridge or box H through which cold
water is made to circulate by means of the pipes h, h', Figure 4, in order
to keep the bridge of the furnace cool. The combustible gas and air
rise from the regenerators below the furnace respectively through, say,_
the-passages-F-and-G-(the air passage G being raised somewhat above
the gas passages F, as shown) and in entering into combustion in the
passage J the resulting flames are caused to impinge in a downward
direction upon the layer A of mixed ore, coal, and fluxing material.
After acting upon this compound the products of combustion escape
through the passages J', F', and G', into the other set of regenerators in
a manner well understood.
The heat thus produced in the furnace effects the before-described
When a sufficient
partial reduction and fusion of a portion of the ore.
quantity of ore has thus been acted upon the more or less liquid mass is
stirred up by means of tools introduced through the side doors L; L, after
which one or both of the side apertures K below the doors L are opened
by removing the ore or slag with which they are closed up (as shown in-
Figure 1) and the liquid mass is raked out through them into the boxes
or moulds M brought up to the spouts of the apertures upon trucks N.
The construction of these moulds is shewn in enlarged longitudinal and
transverse sections at Figures 11 and 12; they are open at top and bottom
and are made to rest with the grooved flange m upon a layer of sand,
clay, or carbon upon the table of the truck N. Before filling them with
the partially converted ore they receive layers of debris of partially
reduced ore and of coke or charcoal as before described. The fluid
portion of the ore on flowing into the moulds fills the interstices and
binds the whole together into lumps or loaves O. When the mass has
solidified it is removed from the mould, the ribs m³, m³, of which form
deep grooves in the loaves O, as indicated in Figure 1, in order that the
whole mass may be more uniformly acted upon in the subsequent
processes. These loaves are then removed to the reducing oven or

page_text: "
section on line 5-5, Figure 7; Figure 6 shows a transverse section
on line 6-6, on Figure 5; and Figure 7 shows, a sectional plan on
line 7-7, Figure 5..
This furnace consists of a series of enclosed chambers P, P, P,
accessible through doors Q, Q, which chambers are contained within
the furnace R, in which a full red heat is maintained by the combustion
of air and gas passing in through. the passages S, S', at the one end or
the other from the regenerators T, T, T², T', in the usual manner. The
tops of the chambers P are formed by preference of hollow fire-bricks,.
as shewn, in order that the heat of the furnace may be readily, transmitted.
to the interior of the chambers. Into these chambers, the lumps or
loaves of partially converted ore mixed with carbon, or the consolidated
and unconverted lumps of ore mixed with carbon and fluxing materials
as before described, are. introduced and maintained at a full red heat
in a reducing atmosphere so as to promote their reduction, for which
purpose either solid or gaseous carbonaceous matter may be introduced
into the chambers. In either case the chambers are entirely enclosed
so as to exclude any sulphurous gases arising from the combustion taking
place in the surrounding furnace. As the lumps or loaves are required
for use they are removed from the heated chambers; or hot store furnace
and conveyed to the steel melting furnace at Z, Figure 1, shown to an
enlarged scale at Figures 8 to 10, Sheet II. Figure S. shows a
longitudinal section on line S-8, Figure 10; Figure 9 shows. a trans-
verse section on line 9-9, Figure 8; and Figure 10 shows a sectional
plan on line 10-10, Figure 8. This furnace is mainly of the same cor-.
struction as those previously described by me in the Specifications to my
former Patents; the principal difference consists, firstly, in the addition
thereto of the heating chamber A for the reception of the lumps or
loaves of more or less converted ore before introduction into the melting
chamber B of the furnace; and, secondly, in the peculiar construction
of the combustible gas and air passages C, D, C, D¹, for effecting the
mixture of the heated combustible gases and air rising up from the
regenerators E, F, E', F. The air passages D, D', are raised very nearly
to the roof of the furnace, while the gas passages C, C¹, open into the
chamber B at a considerably lower point, as shown at Figure 10, and
the side walls G, G', of the air flues are brought forward towards the
12

page_text: chamber B in a converging manner until the meet, as shown at
Figure 10, thus forming widening passages E, E', for the gas to issue
through, the gases on their ascent being deflected and directed into such
widening passages by means of the slabs N fixed over the vertical
passages C, C', while the air is caused to enter the furnace in diverse
directions above the combustible gases, so that these gases in rising
become thoroughly mixed with the air, and thus their complete com-
bustion is effected, while any uncombined air in remaining at the roof
of the furnace is prevented from coming into contact with the metal
on the bed H of this furnace. This bed is formed of pure silicious sand
prepared and mixed with glass powder and then laid in layers upon the
fire-brick lining I of the iron bed J, in the manner as fully herein-before
described. The iron_bed-J-is-open-to-the-surrounding air, in order to
cool the same as in former constructions of my furnaces. For tapping
off the bath of steel when ready for use a hole is formed in the sand
bottom by the introduction of a tool through the spout K, through which
hole and spout the steel then flows off into the ladle L on the carriage M,
shown in Figure 1. The deoxidized and carbonized loaves O having
been introduced into the charging chamber A through the door A¹ are
there-heated to the requisite degree by the radiated heat or by flame from
the melting chamber, a portion of such flame or hot gases being caused
to enter the chamber A through the aperture B', and to circulate through
the same by means of the chimneys A², the tops of which are provided
with slabs A³ for regulating the draught. When sufficiently heated the
loaves are successively pushed forward through the aperture B¹ into
the bath of molten metal in the chamber B where they are melted, and
the process of preparing the bath is carried on in the manner herein-
before described. A charge of molten steel having been received from
the furnace in the ladle L, the carriage M is run upon the rails P
either over a mould carriage running upon rails in a longitudinal trench
as herein-before described, or the ladle is conveyed to wherever required.
Figure 13, Sheet I., shews a plan of the before-mentioned arrangement
of steel melting furnaces with transverse and longitudinal trenches and
tramways. Z, Z, are the furnaces, arranged in two opposite rows, from
the discharging spouts K of which rails P, P, laid along the sides of
transverse trenches Q, Q, extend towards and across a longitudinal
trench R so that the ladle trucks L, M, can be run over the latter.
In the longitudinal trench is the mould carriage S moved along upon

page_text: the rails T either by a chain U driven by an engine, or by any other
suitable means. A charge of liquid steel having been run into the
ladle L, the carriage M is moved over the trench R, and the mould
carriage S is run underneath it so as to enable the metal to be discharged
from the ladle into the moulds. These are then conveyed by the
carriage to wherever required.
Having thus described the nature of my Invention, and the best means
I am acquainted with for carrying the same into practice, I wish it to
be understood that what I claim is,-
First. Producing cast steel by first converting ferruginous ore into
lumps or loaves of partially or wholly reduced metal mixed or combined
with fluxing materials, and by then charging these lumps in a heated
condition into an open hearth steel melting furnace, to be there liquified
by being brought into contact with a bath of cast iron or with other
carbonaceous matter, substantially as herein-before described.
Second. Preparing the aforesaid loaves by melting the ore or mixture
of ores with fluxing materials in contact with carbon, and by charging
this fluid mass into moulds containing coke, charcoal, or other solid
carbonaceous matter, which loaves are thereupon maintained for. some
hours at a full red heat in a reducing atmosphere within a heated
chamber or hot store furnace before they are charged into the steel
melting furnace, substantially as described.
Third. Preparing loaves similar to those aforesaid by crushing the ore,
by mixing it intimately with fluxing materials and with binding coal,
by forcing or placing the mixture into moulds, and exposing the same
for a considerable number of hours to a full red heat in a closed heated
chamber or hat store furnace, substantially as described.
Fourth. Preparing loaves similar to those aforesaid from ores rich in
manganese or other equivalent easily oxidizable metal, together with an
excess of carbon to be charged into the fluid bath of the steel melting
furnace towards the end of each operation in order to impart those metals
to the bath.
Fifth. Constructing the steel melting furnace with a charging chamber,
through which a portion of the hot gaseous products of combustion can
be made to circulate, into which the aforesaid lumps as well as the pig
metal or
other materials to be used are introduced, to be thence
pushed forward in a heated condition into the melting chamber,

page_text: substantially as described with reference to Figures 8. to 10 of the
accompanying Drawings.
Sixth. Constructing the bed of the steel melting furnace of a mixture
of pure silicious sand with glass powder, substantially as herein-before
described.
Seventh. Constructing the air and gas ports of a steel melting furnace
in such manner that the vertical air ports rise nearly to the roof of
the furnace, while the side walls of the flues are extended forward in a
convergent manner until they meet in order that the air may issue into
the furnace in diverse directions above the combustible gas, substantially
as herein-before described with reference to Figures & to 10 of the
acoompanying-Drawings.
Eighth. Arranging one or more rows of steel melting furnaces with
their tapping holes facing a longitudinal trench with lateral trenches
leading to each of the furnaces, upon the edges of or over which trenches
rails are fixed crossing the main trench, ladle carriages being arranged
to run over the lateral trenches in order that the fluid metal may be
discharged into moulds carried upon rails in the central trenol facilitating
their preparation and removal, as herein-before described.
In witness whereof, I, the said Charles William Siemens, have
hereunto set my hand and seal, this Twenty-third day of August,
in the year of our Lord One thousand eight hundred and
seventy
Witness,
JNO. A. HEAD,
3, Great George St.,
Westminster,
S.W.
C. WILLIAM SIEMENS. (L.S.)