IMPROVEMENTS IN THE MANUFACTURE OF IRON
Year: 1880

page_text: LETTERS PATENT to Philip Syng Justice, of 14, Southampton Buildings, in
the County of Middlesex, Engineer, for an Invention of "IMPROVEMENTS IN
THE MANUFACTURE OF IRON." A communication from abroad by Charles
Meredith Dupuy, of the City and County of Philadelphia, in the United
States of America.
PROVISIONAL SPECIFICATION left by the said Philip Syng Justice at the
Office of the Commissioners of Patents on the 17th December 1880.
"
PHILIP SYNG JUSTICE, of 14, Southampton Buildings, in the County of Middlesex,
Engineer. IMPROVEMENTS IN THE MANUFACTURE OF IRON." A communication
from abroad by Charles Meredith Dupuy, of the City and County of Philadelphia,
in the United States of America.
This Invention relates to improvements on the processes set forth in Specifications
Number 1664 of 1877, and Number 3827 of 1880. Iron ores, when sufficiently
heated, may be reduced to a metallic state when brought into contact with carbo-
naceous matter, by reason of the superior affinity which the contained oxygen of
the ores has for carbon. In this condition the oxygen leaves the ore and passes off
chiefly as carbonic oxide.
When in addition to this the earthly substances of the ore are combined with
suitable alkali or acid materials (according to the peculiar constituents of the ore),
a greater affinity may be made between these various substances than they have for
the iron. In this way a liquid glass may be created from these earthly substances,
thereby more effectually preserving the metal from oxydation and consequent
waste..
As the oxygen of the ore is nearly one third of the entire bulk and weight of the
whole, and is evenly blended throughout the mass, it follows that as it passes off
as carbonic oxide there is left infinitessimally subdivided spongy spaces or cells
between the delicate particles of metal. Something must fill the vacuum caused
by the exit of this oxygen. Usually the furnace gases fill these spaces, and where
this is the case (as all furnace gases are more or less oxydising) these delicately

page_text: subdivided walls or granules are reoxydised to such an extent as to bring the yield
of iron down so low as to defeat the commercial economy of the direct process. In
the course of various experiments I have found that the glassy slag may be utilized
by making it of such consistency as will retain it in the masses of metal, causing it
to glaze and seal these metallic granules by filling the spaces or cells vacated by the
oxygen, and thus the re-oxidation of the metal by the furnace gases will be pre-
vented. This discovery I consider of great value, as from a given amount of ore a
larger yield of iron may thus be obtained than by any other direct process known
to me.
Experimental investigation has led me to the further discovery that these suitable
combinations with the earthy matter of the ore will not only effectually separate
deleterious substances from the iron, but will as well prevent reoxidation by sealing
the metallic granules with the glassy slag, and thus prevent the contact of
furnace gases with them. The earthy mixtures should at the same time be made
of such consistency as to hold the entire ore mixture together in such moulded
shapes as will enable the heat to penetrate the masses until the iron comes to
nature in the furnace. This discovery is very important, as under many conditions
it saves the necessity and the cost of the sheet iron canisters or envelopes which are
described in Specification Number 1664 of 1877.
I have further discovered that these combinations may be effectually applied not
only to the working of iron ores but also to droppings from puddling furnaces, from
tap cinder of heating and puddling furnaces, scale from the rolling mills, and from
the waste slag or cinder from blooming hammers. My method is to coarsely
pulverize and intimately commingle ore, tap cinder, droppings from puddling
furnaces, scale from iron, hammer slag, or similar materials, and mix either any
or all of them with pulverized carbonaceous matter.
I have found the slack or fine waste coal from bitumenous or anthracite, or the
fine waste dust from wood charcoal, satisfactory carbon for this purpose, but other
carbonaceous matter may also be used effectively. I have found 15 to 20 per cent.
(by weight of the iron making material) of bitumenous or anthracite carbon to be
sufficient for deoxidation, but as charcoal carbon is more volatile I use of it as high
as 25 per cent. With the pulverized carbon and the iron bearing materials I mix
lime, clay, and sometimes salt, in such proportions as will permit of the combined
mixture being moulded into suitable forms, and when subjected to the furnace heat
will form a glassy non flowing slag which will protect the minute particles of metal
from reoxidation, it being clearly understood that the proportions of these substances
must be varied to suit the analysis of the ore or material to be worked. Some ores
may be highly calcareous, in which case the lime would be in part or wholly left
out. Ores highly aluminous would not require much, if any, clay. In all cases the
ingredients must be varied with the character of the metal making material. In
using "droppings," carrying approximately 40 to 55 per cent. of iron and silica to
the extent of 10 to 15 per cent., I find that 5 per cent. of the whole weight of the
droppings of good aluminous clay and about one half this proportion of lime, and
also 10 to 15 per cent. of scale, will bring the mass to malleable iron ready for
forging in two hours. A small per centage of scale is sometimes effectively use
with ores, and salt is sometimes useful in separating impurities.
"
I have discovered that 10 to 20 per cent. of scale is used with advantage to give
fibre to the iron, as well as to better preserve intact the shape of the moulded
mixture when subjected to the reducing heat of the furnace, and when classes of
ores or other metal making materials are used which have not sufficient tenacity
without it. A further advantage of the aluminous, calcareous, and saline mixtures
is found (by an analysis of the product) to be in passing off the phosphorus,
sulphur, and other impurities in the cinder when the reduced metal is compressed
under the hammer, squeezer, or rolls, as the affinity for most of the impurities,
particularly the phosphorus, is greater for the glassy slag than for the iron at the
temperature at which it comes to nature.
The various substances used in my process may be coarsely pulverized, and

page_text: intimately mixed in a moistened state by means of a pug or other suitable mill.
The substances being then moulded, preferably under considerable pressure, into
suitable shapes or forms, as hereafter set forth, the compression should be such as
to largely express the moisture, and solidify the masses so that they may be
at once charged into a reducing furnace, and in the course of two hours, under a
suitable heat, may be withdrawn, and forged or rolled into blooms or bars of
malleable iron. A further discovery, practically proved, is that the shape of the
moulded mass must be such as to allow the heat to rapidly penetrate it, by not
requiring it to penetrate more than about from one to two inches from the outer
surfaces. While with care and sufficient time a mass having four or more inches
from the outer to the inner surface may be reduced, yet it is at the cost of such
increased time and fuel as to defeat the commercial economy of the process.
It is essential that the furnace operation should be finished as rapidly as possible,
and with the least amount of waste of metal, so as to guarantee a remunerative
output for the investment of plant, fuel, and labour, and this output is largely
dependant upon the shape of the moulded masses.
A series of furnace operations with various moulded shapes have proved the best
form to be tubular cylindrical masses, which I prefer to set on end throughout the
furnace, spaced sufficiently apart for a free circulation of heat. These tubular
masses should have holes or openings from their outer to their inner walls, so as to
secure a free circulation of heat both without and within them. These tubular
masses are advantageously formed by machinery, similar to that employed in the
manufacture of ordinary drain pipes.
I have tried various moulded shapes; they may be made cubes, sexagons,
octagons, or rectangular, but none of these give the same extent of surface for
the action of heat as the tubular form, herein described, and hence will not produce
an equal output of metal in the same given time.
The size of these tubular masses is also governed by the facility of handling
them into the furnace. I find 16 to 18 inches high, and outside diameter of 7 to
8 inches, and cored 2 to 22 inches, to be convenient dimensions for readily sliding
into the furnace on a «
peel." If higher, they are not quite so easily charged,
unless made thicker, and then they are not so rapidly penetrated with heat and
reduced, and so extend the length and cost of the furnace operation. Moulding
into shapes of the dimensions above given enables me to give large area of surfaces
for heat absorption and generation. The effect of this is the moment the highly
heated furnace is charged with the moulded material properly placed the gases
generated by the action of the heat upon them are quickly enflamed from all the
surfaces. These gases envelope the outer surfaces of the moulded mixtures, and
protect them from furnace oxidation, so that the heat may be rapidly increased
from the outset of the operation without decreasing yield, and thus bring the
system to a practical working economy by reducing the furnace operation to
approximately two hours duration.
I am aware that previous to my Invention ores have been mingled with carbon
and other substances, and subjected to the action of heat in reverberatory furnaces
for the purpose of reducing them from their oxides, as well as to free them from
earthy impurities. Sometimes the mixtures have been moulded into the form of
bricks, and charged into the furnace, but in such large masses and so arranged as
to prevent rapid reduction, and thus to defeat the commercial economy and value
of this process. Ore mixtures have been spread and stirred on the hearths of one
or more communicating heated reverberatory furnaces. They have been revolved
in heated cylindrical furnaces. In all these different ways the prime object has
been to secure a direct and rapid reduction and separation from impurities, so as to
withdraw and shingle balls of malleable iron more quickly and with less cost than
by its production from pig iron.
While the large moulded masses failed to secure economical working owing to
the long period of time required for reduction, the fuel consumed, and the waste of
iron from oxidation, the stirring and rotating method has also been objectionable

page_text: for the reason that the frequent exposure of partly deoxidised granules of spongy
ore to the surface action of oxidising furnace gases causes reoxidation and
consequently large waste of iron to cinder.
I have discovered that the necessity exists of keeping the metal making material
in a perfectly quiescent state during the process of reduction, and on this point I
lay great stress, as also on the necessity of so combining the mixtures as to form
the liquid non-flowing glass which enters the cavities or cells vacated by the oxygen,
and so protects the metal from the oxydising effects of the flame until the masses
are withdrawn and hammered, squeezed, or rolled, when the glass or cinder is
rapidly and easily expressed, leaving the metal in a remarkably pure and
homogenous mass from which it can be immediately rolled.
When the mixtures are properly combined, the moulded material may be
subjected to a sufficient heat to secure rapid reduction without injury to the metal.
No one previous to my Invention has to my knowledge been able to make
malleable iron by one direct reduction of the ores of iron and the materials herein
named, and to effect such a commercial success in its attainment as by my process
of preparing the iron producing materials combined with such proper mixtures as
admits of their being rapidly and cheaply compressed in moulds of such shapes as
will hold the materials compactly together under the action of a reducing heat, and
at the same time allow it to penetrate rapidly, not requiring it to travel
substantially more than from one to two inches from the inner and outer surfaces
for the purpose of effectively reducing the metal and yet sealing the particles of
newly made iron against reoxidation, whilst at the same time the gangue is being
utilized (by combining with the various ingredients) in forming the glassy slag and
taking up the impurities which would otherwise enter the iron.
A further peculiarity and advantage in charging these small masses of metal
bearing material into the reverberatory or reducing furnace of such described
shapes as are readily permeable by heat is that the rapid combustion of the gases
formed by the combination of the oxygen of the ore with the carbonaceous matter,
which is so intimately blended in the mixture, serves as a means of quickly creating
throughout the entire hearth of the furnace a continuous and powerful but mild
heat, the reflection of which from the furnace roof, added to the heat generated
from the furnace grates or gas producer, not only causes a very rapid reduction of
the metal making substances to nature, but also effects a great economy of fuel.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Philip Syng Justice in the Great Seal Patent Office on the 14th
June 1881.
PHILIP SYNG JUSTICE, of 14, Southampton Buildings, in the County of Middlesex,
Engineer. "IMPROVEMENTS IN THE MANUFACTURE OF IRON.". A communication
from abroad by Charles Meredith Dupuy, of the City and County of Philadelphia,
in the United States of America.
This Invention relates to improvements on the processes set forth in Specifications
Number 1664, of 1877, and Number 3827, of 1880. Iron ores (when sufficiently
heated) may be reduced to a metallic state when brought into contact with
carbonaceous matter by reason of the greater affinity which the contained oxygen
of the ores has for the carbon. In this condition the oxygen leaves the ore and
passes off chiefly as a carbonic oxide. When in addition to this the earthy
substances of the ore are combined with suitable alkali or acid materials (according
to the peculiar constituents of the ore) a greater affinity may be created between
these various substances than they have for the iron itself. In this way a liquid
glass can be created from these earthy particles, which, to a great extent, will
effectually preserve the metal from oxydation, and consequent waste, if all the
particles are properly and intimately commingled. As the oxygen of the ore
forms nearly one third of the entire bulk and weight of the whole, and is evenly
blended throughout the mass, it follows that as it passes off in its gaseous form
there will be left infinitesimally subdivided spongy spaces or cells between the
delicate particles of metal from which it separates. Something must fill this vacuum
caused by the exit of the oxygen. Usually the furnace gases quickly enter these
spaces, and where this is the case (as all furnace gases are more or less oxydysing)
these delicately subdivided spongy walls and particles of iron are reoxydized to so
great an extent as to bring the yield of iron down to so small a quantity as to
defeat the commercial economy of the direct process. In the course of various
experiments I have found that the glassy slag herein before alluded to may be
utilized by making it of such consistency that it will be retained throughout the
mass of metal, completely glazing and sealing up those cells and metallic granules
of iron by filling the spaces vacated by the oxygen, and thus the re oxidation and
waste of the metal by the furnace gases will be prevented. The combination made
of these substances may at the same time be such as will take up largely the
impurities contained in the iron, and leave it in a comparatively pure state after
being hammered. This discovery I consider of great value as from a given amount
of ore a larger and purer yield of iron may thus be obtained than by any other
direct process known to me. The earthy mixtures should at the same time be of
such consistency as to hold the entire ore mixture together in such moulded shapes
as will enable the heat to penetrate the masses until the iron comes to nature in
the furnace. This discovery is very important, as under many conditions it saves
the necessity and the cost of the sheet iron canisters or envelopes which are
described in my Specification Number 1664, of 1877. I have further discovered
that these combinations may be effectually applied not only to the working of iron
ores but also to droppings from puddling furnaces, and the tap cinder of heating
and puddling furnaces, to scale from the rolling mills, and from the waste slag or
cinder from blooming hammers, as well as to purple ore or blue billy. My method
is to coarsely pulverize and intimately commingle ore, tap cinder, droppings from
puddling furnaces, scale from iron, hammer slag, blue billy, or similar materials,
and mix any or all of them primarily with pulverized carbonaceous matter. I
have also found the slack or fine waste from bituminous or anthracite coal, or
the fine waste dust from wood charcoal, satisfactory forms of carbon for this
purpose, but other carbonaceous matter may also be used effectively. I have
found 18 to 20% (by weight of the iron making material) of bituminous
or anthracite carbon to be sufficient for deoxidation, but as charcoal carbon
is more volatile I use as high as 25 per cent. of it. With the pulverized
'

page_text: °
The
carbon and the iron bearing materials I mix lime, aluminous clay, black oxide of
manganese, and sometimes salt, in such proportions as the iron bearing material
may require, which will permit of the combined mixture being moulded into suitable
forms previous to being subjected to the furnace heat, and which will form the
glassy non flowing slag before described. The proportions of these substances
must be varied to suit the analysis of the ore or material to be worked. Some
ores may be highly calcareous, in which case the lime would be in part or wholly
left out. Ores highly aluminous would not require much, if any, clay. In using
"droppings" or tap cinder, carrying approximately 45 to 55 per cent. of iron, and
15% to 25% of silica, I find that 6 to 10% of the whole weight of the droppings
of good aluminous clay, and about one half of this proportion of lime with 10 to
15% of scale and half per cent. of black oxide of manganese, will bring the
mass to malleable iron ready for forging in about two hours under a proper heat.
A small per centage of scale is sometimes effectively used with ores, and salt also
is useful in separating the impurities. I have discovered that 15 to 30 per cent.
of scale may be used with great advantage to give fibre to the iron when reducing
tap cinder or droppings, as well as to better preserve intact the shape of the moulded
mixture when subjected to the reducing heat of the furnace, and when certain
classes of ores or other metal making materials are used which have not sufficient
tenacity without it. A further advantage of the aluminous, calcareous, and saline
mixtures is found (by an analysis of the product) to be in passing off the phosphorus,
sulphur, and other impurities in the cinder when the reduced metal is compressed
under the hammer, squeezer, or rolls, as the affinity for most of the impurities,
particularly the phosphorus, is greater for the glassy slag than for the iron at the
temperature at which it comes to nature by this process. The various substances
used in my process should be pulverized to about the fineness of sand, and intimately
mixed in a moistened state by means of a pug or other suitable mill.
substances being then moulded, preferably under considerable pressure, into suitable
shapes or forms, as hereafter set forth, the compression should be such as to largely
express the moisture and solidify the masses, so that they may be at once charged
into a reducing furnace, and in the course of about two hours, under a suitable
heat, they can be withdrawn and forged or rolled into blooms or bars of malleable
iron. A further discovery, practically proved, is that the shape of the moulded
mass must be such as to allow the heat to rapidly penetrate it from all its surfaces
by not requiring it to penetrate more than about from one to one and a half inches
from the outer surfaces. While with care and sufficient time a mass having four or
more inches from the outer to the inner surface may be reduced, yet it is at the cost
of such increased time and fuel as to defeat the commercial economy of the process.
It is essential that the furnace operation should be finished as rapidly as
possible and with the least amount of waste of metal, so as to guarantee a
remunerative output for the investment of plant, fuel, and labor, and this
output is largely dependant upon the shape of the moulded masses. A series
of furnace operations with various moulded shapes have proved the best
form should be tubular cylindrical masses, which I prefer to set on end through-
out the furnace, spaced sufficiently apart for a free circulation of heat. These
tubular masses should have holes or openings from their outer to their inner
walls so as to secure a free circulation of heat both without and within them.
The tubular masses are advantageously formed by machinery similar to that
employed in the manufacture of ordinary drain pipes. I have tried various
moulded shapes they may be made similar to the shape of the letters C, U, S, in
solid or hollow polygons; and many other shapes, but none of these give the same
extent of surface for the action of heat as the tubular cylindrical form herein before
described, and hence will not produce an equal out put of metal in the same given
time. The size of these tubular cylindrical masses is governed by the facility of
handling and charging them into the furnace. I find 16 to 18 inches in height,
and an outside diameter of 7 to 8 inches, cored 2 to 2, inches throughout its
length, to be convenient dimensions for readily sliding these masses into the furnace

page_text: on a "peel;" if higher, they are not quite so easily charged unless made thicker, and
then they are not so rapidly penetrated with heat, and thus increase the cost of
the furnace operation. Moulding into shapes of the dimensions above given enables
me to give large area of surfaces for heat absorbtion and generation. The effect of
this is that directly after the highly heated furnace is charged with the moulded
material properly placed, the gases generated by the action of the heat upon them
are quickly enflamed from all the surfaces; these gases envelope the outer surfaces
of the moulded mixtures and protect them from furnace oxidation, so that the heat
will be rapidly increased almost from the outset of the operation without decreasing
yield, and thus I bring the system to a practical working economy by reducing
the furnace operation to approximately two hours duration. I am aware that
previous to my Invention iron ores have been mingled with carbon and other
substances, but with a very slight regard to the proportions of such materials or
their relative effects and action upon the metalloids with which they were supposed
to combine, and aid in the production of the iron to be produced from the mixtures,
and these have been subjected to the action of heat in special descriptions of
reverbatory furnaces for the purpose of reducing them from their oxides, and
theoretically to free them from earthy impurities, but no commercial success has
ever been attained by any of such processes to my knowledge, as no uniform rules
have been established for the working of these ores such as I now propose.
Sometimes mixtures have been moulded into the form of bricks and charged into
blast and heating furnaces, but in such masses and so arranged as to prevent rapid
reduction, and thus to defeat the commercial economy and value of this process.
Ore mixtures have been spread and stirred on the hearths of one or more communi-
cating heated reverberatory furnaces. They have been revolved in heated
cylindrical furnaces. In all these different ways the prime object has been to
secure a direct and rapid reduction and separation from impurities so as to with-
draw and shingle balls of malleable iron more quickly and with less cost than by its
production from pig iron. While large moulded masses have failed to secure
economical working (owing to the long period of time required for their reduction)
the fuel consumed, and the waste of iron from oxidation; the stirring and rotating
method has also been objectionable for the reason that the continuous exposure of
the partly deoxidised granules of spongy iron to the surface action of oxidising
furnace gases.causes reoxidation, and consequently large waste of iron, which goes
into the form of cinder. I have discovered that the necessity exists of keeping the
metal making material in a perfectly quiescent state during the process of reduction,
and on this point I lay great stress, as also on the necessity of so combining the
mixtures as to form the liquid non flowing glass or slag which enters the cavities or
cells vacated by the oxygen, and thus protects the metal from the oxydising effects of
the flame until the masses are withdrawn, hammered, squeezed, or rolled, when the
glass or cinder is rapidly and easily expressed, leaving the metal in a remarkably pure
and homogenous mass, from which it can be immediately passed through the rolls.
When the mixtures are properly combined the moulded material may be subjected to
a sufficient heat to secure rapid reduction without injury to the metal. To recapitulate
I may say that no one previous to my Invention has to my knowledge been able
to make malleable iron by one direct reduction of the ores of iron, and the
materials berein named, and to effect such a commercial success in its attainment
as by my process of preparing the iron producing materials combined with such
proper mixtures as admits of their being rapidly and cheaply compressed in moulds
of such shapes as will hold the materials compactly together under the action of a
reducing heat and at the same time allow it to penetrate rapidly, not requiring it
to travel substantially more than from one to two inches from the inner and outer
surfaces for the purpose of effectively reducing the metal and yet sealing the
particles of newly made iron against reoxidation, whilst at the same time the
gangue is being utilised (by the combustion of the various ingredients) in forming
the glassy slag and taking up the impurities which would otherwise enter the iron.
A further peculiarity and advantage in charging these small masses of metal bearing

page_text: "
material into the reverbatory or reducing furnace of such described shapes as are
readily permeable by heat is that the rapid combustion of the gases formed by the
combination of the oxygen of the ore with the carbonaceous matter which is so
intimately blended in the mixture serves as a means of quickly creating throughout
the entire hearth of the furnace a continuous and powerful heat, the reflection of
which from.the furnace roof, added to the heat generated from the furnace or gas
producer, not only causes a very rapid reduction of the metal making substances to
nature but also effects a great economy of fuel. It will be seen that by the
intimate commingling in proper proportions of the various substances which I have
named as composing the mixtures used that I bring the particles of each into such
close contact that the effect must be to de-phosphorize-de-sulphurize, de-siliconize,
and de-oxydize the iron, as at the temperature at which the iron comes to nature
said impurities have a greater affinity for the slag which is formed than for the iron
itself.
Having thus described the nature of the Invention of my foreign correspondent,
what I claim and desire to secure by Letters Patent is,-
First. The improvement in the manufacture of malleable iron, as herein before
described, consisting in combining in proper proportions pulverised iron bearing
carbonaceous, fluxing, and binding materials of such character as will permit of
their being compressed into moulded masses which will practically retain their
forms when subjected to the heat of a reducing furnace until the metal in them
comes to nature," whilst at the same time their other contained substances will
form a substantially-non flowing-glazing slag-for the purpose of preserving the
newly formed metal from oxydization, substantially as and for the purpose set forth.
Second. The improvement in the manufacture of malleable iron, as hereinbefore
described, consisting in moulding the pulverized iron bearing carbonaceous, binding,
and fluxing substances into such forms (preferably perforated tubular cylinders) as
will present the greatest amount of surface to the action and circulation of the
heat of a furnace, substantially as and for the purposes specified.
Third. The improvement in the manufacture of malleable iron, as herein before
described, consisting in combining iron or steel "scale" with iron bearing carbon-
aceous, fluxing, and binding materials (chiefly for the purpose of producing fibrous
iron), then moulding the combined substances into suitable forms, as herein before
described, to be subsequently reduced by the action of furnace heat, as and for the
purpose set forth.
Fourth. The improvement in the manufacture of malleable iron, as herein before
described, consisting in de-oxydizing-de phosphorizing de-sulphurizing, and de-
siliconizing iron bearing substances and ores by intimately commingling with them
in a pulverised moist condition the ingredients as described, and compressing the
mixture into suitable forms, as set forth, to be subsequently reduced in a furnace,
then hammered or squeezed and rolled into malleable shapes or bars.
In witness whereof, I, the said Philip Syng Justice, have hereunto set my
hand and seal, this Thirteenth day of June, in the year of our Lord 1881.
Signed and sealed by the said
Philip Syng Justice, in the
presence of
PHILIP M. JUSTICE,
14, Southampton Bdgs.,
Chancery Lane, London,
Patent Agent.
PHILIP S. JUSTICE. (L.S.)