IMPROVEMENTS IN THE MANUFACTURE OF IRON AND STEEL
Year: 1874

page_text: LETTERS PATENT to Williamı Alexander Lyttle, of The Grove, Ham-
mersmith, in the County of Middlesex, Engineer, for the Invention-
T.
PROVISIONAL SPECIFICATION left by the said William Alexander
Lyttle at the Office of the Commissioners of Patents, with his
Petition, on the 1st September 1874.
<
I, WILLIAM ALEXANDER LYTTLE, of The Grove, Hammersmith, in
the County of Middlesex, Engineer, do hereby declare the nature of
the said Invention for " IMPROVEMENTS IN THE MANUFACTURE OF IRON AND
STEEL." to be as follows :-

page_text: diameter at the point of greatest heat. At one or more places in the
sides of this furnace, at or near its bottom, there are provided openings,
through which flame or incandescent carbonic oxide gas can enter
for the purpose herein-after described. At and to the bottom of this
furnace an iron cylinder is attached (air-tight) as a continuation of the
interior of the furnace vertically downwards, and this cylinder is thus
carried downwards to a depth of about thirty feet or more. The outside
of this cylinder may be surrounded with a spiral or screw feather or
shelf of iron, filling across an interval between the outside of the
cylinder and the inside of a concentric brick cylinder or well which
surrounds the iron cylinder, and also acts as the foundation or pedestal
for the furnace above. A blast of cold air may be made to traverse this
spiral passage, not only for the purpose of cooling the contents of the
cylinder, but also of being made thereby hot and ready for use in the
heating or carbonic oxide furnace hercin-after described.
When this reducing furnace is at work the action is as follows:-
Incandescent carbonic oxide gas enters the reducing furnace from
an adjoining heating furnace by passing through the openings herein-
before referred to, and passes upward to the top of the reducing
furnace, where it escapes for utilization as gascous fuel or as waste.
This gas in its course amongst the lumps of the charge reduces the
iron to the metallic state. When the reduced iron thus produced
sinks down in the course of work below the apertures of the heating
zone and into the iron cylinder, it gradually gives up its heat through
the sides of the cylinder to the ascending blast of cold air on the outside.
At the bottom of this cylinder the reduced iron can be withdrawn
periodically in a cold state, and it can then be cleansed for use in the
following manner:-If plastic clay has been used for the consolidation
of the charge it will be necessary to break to dust by means of a mill
the Kumps containing the reduced iron, and the latter can then be
washed free of the clay and unconsumed fuel in the same way as sand
is washed by builders for mortar, or it can be cleansed by the winnowing
machine described below.
If lime or chalk has been used the reduced lumps when powdered
can either be treated, as last mentioned, with water, or the iron.and
lime can be separated by means of a winnowing apparatus, like that
used in corn mills, the final egress of the winnowing blast being through
a woven screen, which lets out the air but retains the lime dust.
Thu

page_text: latter arrangement is especially valuable when a mixture of clay and
lime or hydraulic cement is employed as the consolidating medium,
because in either case the calcareous dust, when suitable proportions of
clay and lime are used, is hydraulic cement, and is therefore ready if
kept dry for use again as the means of consolidating a further supply
of ore and carbonaccous matter. When iron dust is separated by
winnowing it falls at a very short distance, whilst the other dusty
particles are borne much further by a suitable blast.
A magnetic or electro-magnetic separator of any of the descriptions
now in use for arresting and separating iron filings in workshops from
other dust can also be employed as an auxiliary means, in conjunction
with the aforesaid wind or water arrangements, for treating the reduced
dust so as to complete the removal of the metal.
A mixture of one part of silicious clay, like that known as "London
clay," and about two parts lime or chalk well ground together into a
creamy "slip" will when passed through the reducing furnace bo
converted into good hydraulic cement; and where suitable clay and
lime are cheap the production of such cement may be made to pay for a
large share of the expenses attending the consolidation and reduction of
the ore.
When it is desirable to obtain a cement with a good colour it may be
necessary to expose the dust of the cement after separation from the
iron on the hearth of a reverberatory furnace with frequent turning
over, in order that any unconsumed carbon may be burned away.
The heating furnaco must be a blast furnace of any desired, shape,
the principal condition being that the blast or the flame produced
thereby shall have to pass through such a body of incandescent fuel
that on entering the apertures which admit it into the reducing furnace
it shall consist chiefly or wholly of carbonic oxide gas. The heat of this
gas must be kept down to that temperature which may be found on
trial to be not more than sufficient to effect the reduction of the charge
under treatment.
Good raw or 64
green" wet peat by itself alone and without any
admixture of peat charcoal or coal dust will answer with some ores both
for the consolidation of the broken ore and its subsequent deoxidation,.
as herein-before described. It is not essentially indispensable however

page_text: that the ore and fuel should be used as powders mixed and consolidated
into masses, because lump orc and lump fuel can also be employed in
the reducing furnace, but not to so good economical effect.
The reduced iron can either be heated in a reverberatory furnace and
worked up as malleable iron; or it can be melted in such a furnace in a
bath of pig iron of any desired composition, with or without the addition
of spiegel eisen, so as to form steel.
Instead of having a reducing furnace of brickwork, as herein-before
described, that furnace may be made of iron or thick fire-clay cylinders
forming an upright flue and surrounded with a fire-brick lining at some
distance from the outer surface of the cylinder. The charge of ore and
carbonaceous matter would be subjected to the action of incandescent
carbonic oxide passing through it, as already described, and the waste
carbonic oxide could then be made to impart heat to the reducing
cylinder externally by being conveyed in a return flue from the top of
the reducing cylinder downward for combustion at such points as might
be found desirable.
Coal, coke, or any other fuel may also be employed as an independent
means of externally heating this reducing cylinder.
In order to render the iron ore more friable, and therefore less costly
to crush, I immerse it or otherwise cover it suddenly with cold water
when it is red hot. The simplest way of doing this is to construct two
or more dams upon a stream of water, the higher one serving as a
reservoir for water, whilst the lower dams shall serve as the sites upon
which to roast the iron ore in the ordinary way. During the roasting of
the ore the roasting dam is kept clear of water, but when the roasting
is completed the escape sluice or gates of that dam are shut and the
sluice or gates of the reservoir are quickly opened. The result is that
the bank or mound of red-hot ore is shattered and torn up by the
explosive shock produced by the water. Where such a fall for the
water, and therefore cheap construction of dams, is not available the
roasting of the ore can be conducted upon wide platforms of iron covered
with slabs of fire-clay, and balanced at two oppsoite sides upon heavy
journal bearings, somewhat like a weighing machine. When the ore
roasted on this platform is ready for wetting the platform can be
released so as to tilt over, one side being made to slightly overbalance
the other for the purpose, and the mass of red-hot ore will then plunge

page_text: into a pond of water provided alongside for the purpose. On letting off
the water from this pond the ore can be removed for crushing and for
further treatment, either as described in this Specification, or according
to any other process requiring crushed iron ore..
Office on the 27th February 1875.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, WILLIAM
ALEXANDER LYTTLE, of The Grove, Hammersmith, in the County
Middlesex, Engineer, send greeting.
]
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the First day of September, in the
year of our Lord One thousand eight hundred and seventy-four, in the
thirty-eighth year of Her reign, did, for Herself, Her heirs and suc-
cessors, give and grant unto me, the said William Alexander Lyttle, Her ]
special licence that I, the said William Alexander Lyttle, my executors,
administrators; and assigns; or such others as I, the said. William
Alexander Lyttle, 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 law-
fully might make, use, exercise, and vend, within the United Kingdom
of Great Britain and Ireland, the Channel Islands, and Isle of Man,
Invention for " IMPROVEMENTS IN THE MANUFACTURE OF IRON AND STEEL,"
upon the condition (amongst others) that I, the said William Alexander
Lyttle, 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.
an

page_text: is to be performed, to be particularly described and ascertained in and
by the following statement:-
The leading feature of this Invention consists in the consolidation of
crushed iron ore and powdered fuel or other carbonaceous matter into
lumps by the following peculiar means, and the production from such
lumps of malleable iron or steel in the form of powder by means of heat
applied directly to and amongst the lumps by means of red-hot carbonic.
oxide gas.
In carrying this Invention. into effect I incorporate the roasted and
crushed ore with any suitable powdered or plastic carbonaceous matter
such as coal, coke, peat charcool, or wood charcoal, the proportions of
ore and carbonaceous matter being such that the latter ingredient shall
not be more than very slightly in excess of the quantity chemically
cquivalent to the oxygen combined with the iron of the ore when
malleable iron only is intended to be produced, but when the reduced
metal is desired to be converted by the herein-after mentioned cemen-
tation method directly into steel a considerable redundancy of carbon
beyond the reducing proportion will be required. I next consolidate this
mixture into masses or lumps by any of the following methods,
namely,―
:
Firstly. By means of raw or green peat, as described in the Specifi..
cation of my Letters Patent, numbered 1096, entitled "Improvements
in the Preparation and Use of Peat and Peat Charcoal for Smelting and
other Purposes," dated the Thirtieth of March 1874.
Secondly. By means of a thin slip or cream of very plastic clay or
stiffly plastic clay pugged into incorporation with the ore and fuel, or by
means of admixture with the sedimentary matter of sewage known as
sludge," or by a mixture of lime and clay..
Thirdly. By means of a smail per-centage of Portland or other
hydraulic cement or hydraulic lime, so as to form a concrete in the
manner common to builders.
Fourthly. By means of a cream of quicklime, allowing the mixture
to harden by the lime becoming partly converted into carbonate or chalk
only, as a puddled paste can be used as the binding means of con-
solidation.
:

page_text: Fifthly. By using bituminous coal dust as the carbonaceous matter;
and coking the mixture after consolidation into lumps by any of the
foregoing methods.
The various methods herein-before mentioned have already been
described by me in the Specifications of my several Patents of last year
as the means of effecting an exactly similar consolidation of crushed
iron ore, carbonoceous matter, and fluxes required in carrying out my
precesses for producing pig iron.
When the ore and carbonaceous matter is thus made into lumps these
lumps are subjected to reduction as follows:-A furnace A, B, Figure 1,
is built in any of the various ways now. pursued in erecting blast fur-
naces, but with this difference, that the body is not necessarily reduced
in diameter at the point of greatest heat. At one or more places C, T,
in the sides of this furnace, at or near its bottom, there are provided
openings through which the flame or incandescent carbonic oxide gas
produced in adjacent side furnaces can enter for the purpose of heating
and reducing the ore, as herein-after described. At and closely attached
air tight to the bottom of this furnace there is an iron cylinder R, K,
which serves as a continuation of the furnace vertically downwards to
such depth as may be found most desirable for ensuring its efficiency as
a cooler of the reduced contents of the furnace A, B, in the following
manner:―The outside of this cylinder may be surrounded with a spiral
or screw feather or shelf S, S, S, spanning as a diaphragm the interval
between the outside of the cylinder and the inside of a concentric brick
cylinder or well which surrounds the iron cylinder R, K, and also acts
'as the foundation for the furnace A, B, above. A blast of cold air may
be made to traverse this spiral passage not only for the purpose of cooling
the contents of the cylinder but also of being made thereby hot and
ready for use in the heating or carbonic oxide gas furnace hercin-after
described. W, Figure 1, is the mouth of the pipe leading the heated
air to the carbonic oxide gas furnace.
The red hot carbonic oxide gas which enters the reducing furnace A, B,
is of course mixed with nitrogen from the air of the blast, and this
gaseous mixture after passing through the reducing furnace may be
utilized as gaseous fuel in the usual manner. This carbonic oxide gas
not only acts as the most effective vehicle of heat to the lumps of con-

page_text: solidated ore and carbonaceous matter, but also co-operates with the
latter in reducing the iron of the ore to the metallic state.
On first bringing this furnace into use it is necessary to fill the
receiver R, Z, with ignited coke, the periodical removal of which will
bring down the reduced metal till the metal or reduced materials alone
occupy the receiver. When the reduced iron thus produced sinks down
in the course of work below the apertures of the heating or reducing
zone, and into the iron cylinder R, K, it gradually gives up its heat
through the sides of the cylinder to the surrounding blast of cold air on
the outside. At the bottom of this cylinder the reduced iron can be
withdrawn periodically in a cold state through the air-tight door Z, and
it can then be freed from carbon and mineral impurities in the following
manner-Under any circumstences, but especially when plastic clay
has been used for the consolidation of the ore and carbonaceous matter,
it is desirable to break to dust by means of a mill or disintegrator the
lumps or masses containing the reduced iron or steel when that metal is
produced in the following way, and the metal can then be freed from all
other lighter matter in the same way as sand is washed free of mud by
builders when prepared for mortar.
The reduced contents of the furnace when ground to powder can also
be separated still more easily by means of a winnowing machine like.
that used by farmers and millers. When the reduced powder is passed
through such a machine or made to fall in front of a blast the iron falls
at a very short distance, whilst the other ingredients of the powder are
carried to longer distances in proportion to their specific gravities. The
final egress of the winnowing blast should be through a woven screen or
partition which shall let out the air, but keep back the lighter dust.
The latter arrangement is especially valuable when a mixture of lime
and clay in the proportions generally used in making hydraulic-cement
is employed as the consolidating material, or when ready made hydraulic
lime or cement is used for the same purpose, because in either case the
calcareous dust is revived or anhydrous hydraulic cement, and is there-
fore again ready if kept dry for use as the means of consolidating a
further supply of ore and carbonaceous matter.
A magnetic or electro-magnetic separator of any of the descriptions
now in use for arresting and separating iron filings in workshops from
dust, and the filings of brass can also be employed as an auxiliary means'

page_text: in conjunction with either of the aforesaid wind or water methods for
treating the reduced powder, so as to complete the removal of the
iron therefrom, and to ensure its entire separation from any copper
which may have been reduced to the metallic state by the same
process.
The heating carbonic oxide furnace, which supplies the flame to the
reducing furnace A, B, may be a blast furnace of any desired shape, the
principal condition being that the blast or the flame produced thereby
shall have to pass through such a body of red-hot fuel that on entering
the reducing furnace it shall carry with it no free oxygen. It is how-
ever desirable that carbonic oxide should be present, because of its
reducing power, and the heat of the flame should not be allowed to
exceed the temperature, which is barely necessary for the deoxidation of
the ore when malleable iron only is required, but a higher temperature
short of fusion of the iron is desirable when cementation steel is intended.
to be produced direct from the ore.
39
Good "raw or wet peat by itself alone, and without any admixture
of coal dust or peat charcoal, will answer with some ores, both for the
consolidation of the crushed ore and the supply of carbon for its subse-
quent deoxidation, as herein-before described. Wherever I refer to
crushed ore I should also be understood to refer to all naturally pul-
verulent or clay-like ores and ferruginous sands. It is not indispensably
necessary that the ore and earbonaceous matter should be used in a
powdered state, and consolidated in admixture into lumps, because
lumpy or gravelly ore and lumpy fuel can also be employed in the afore-
said reducing furnace, as described, but not to so good economical
effect.
When reduced malleable iron is made by this process it can either be
heated in a reverberatory furnace, and worked into blooms for rolling
as malleable iron bars or plates or wire, or it can be melted in such a
furnace in a bath of pig iron of any desired composition, with or without
the addition of spiegel eisen, as in the well known Bessemer process, so
as to form steel.
Instead of boxing ค reducing furnace built of brickwork or other

page_text: from the said iron or fire-clay furnace, and in the intervening space thus
provided the escaping carbonic oxide, which has done its work in the
reducing furnace may be burned, and thus made to impart heat externally
to the reducing furnace.
Coal, coke, or other fuel may also be used as an independent means,
if desired, of externally heating the reducing furnace in order to augment
the efficiency of the carbonic oxide within.
In order to render the iron ore more friable, and therefore less costly
tö crush for incorporation with carbonaceous matter in accordance with
this and all my iron smelting Patents of last year, I immerse it or other-
wise cover it suddenly with cold water when it is red hot. A simple
way of doing this is to construct two or more dams or dry docks in the
line of a stream of water with a good fall, the higher one serving as a
reservoir for the water when required, whilst the lower dams shall servo
as the sites upon which to roast the iron ore in the ordinary way.
During this roasting or calcining of the oro the roasting dam is kept
clear of water, but when the roasting of the ore is completed the sluice
gates of that dam on its outlet side are closed, and the sluices or gates
of the reservoir are quickly opened. The result is that the bank or
mound of red hot ore is shattered and torn up by the explosive shock.
produced by the water. A similar roasting heap may be burning in a
similar dam adjoining at a lower level, and the water may be run off
from the first calcined mound of ore to suddenly drown and break up
the second, and so on as far as the fall of the stream will admit.
existing calcining oven for roasting ore will answer for this purpose by
providing a dock or pond with water close alongside the oven, into
which the ore when roasted can be shot by unfastening a grating at the
bottom of the oven. The sides and bottom of the oven so adapted should
be inclined towards the said grating sufficiently to compel the ore to
roll out of the grating by gravitation alone. Arrangement should also
be made for the removal of the water from the dock or pond by allowing
it to escape by a sluice or otherwise in order to take out the submerged
ore.
Any
When iron ore or ferric oxide is brought to the metallic state at the
lowest reducing heat under this process the resulting metal will always

page_text: a more prolonged period of contact with augmented heat when found
needful between the iron and the powdered carbon. In order to accom
plish this result it is necessary to incorporate a much larger proportion
of carbonaceous matter or charcoal with the ore for the purpose of
furnishing thereby the carbon of cementation, which shall by its close
and almost molecular contact with the finely divided iron convert it into
that carburetted condition which in the case of large bars of iron
subjected to cementation in charcoal is known as " blister steel." This
conversion by cementation is effected either by keeping the reduced iron
for a sufficiently long period in the shaft of the furnace A, B, Figure 1,
before causing its subsidence, as herein-before described, by drawing any
reduced material from the bottom at Z, thus exposing it during that
time to the continued action of the reducing flame whilst intermixed
with the residual or redundant carbon. On the other hand this process
of cementation may be partly or wholly confined to the receiver R, K,
Figure 1, by making the upper part of the receiver of non-metallic
materials, with the view of preventing the loss of heat by radiation, and
continuing the red heat and cementation for a longer period before the
lower metallic portion of the receiver is reached, in which, as herein-
before described, the reduced materials are cooled before exposure to the
air or final removal at Z. Again, this same upper portion of the receiver
may be made as a cylinder of iron or fire-clay, and may be maintained
at a high temperature by means of a flame of carbonic oxide or other
heating agent applied externally for the purpose of affording the
prolonged heat necessary for the cementation of the reduced iron into
steel.
By terminating the bottom of the reducing furnace A, B, Figure 1,
with a conical shoot, as shown in Figure 2, C, D, E, such shoot being
closed by any suitable air-tight valve E, the contents can when desired
be withdrawn periodically into air-tight metallic drums or box trucks in
which to become cold, or by means of which the necessary mixture of
reduced iron and redundant carbon may be transferred without exposure
to the air to a separate oven or furnace in which the needful prolongation
of heat may be provided for cementation into steel. In the latter case
and in any other it may be found desirable to crush to powder the
reduced contents of the furnace at or near the bottom of the latter.
This can readily be effected without admission of air by providing a
grating of rotary ribbed fire-bars C, D, Figures 2 and 3, so geared by

page_text: the train of spur wheels B₁ that the projecting ribs of the bars shall
never touch each other during rotation, but shall preserve the relative
positions shown in Figure 3. The axles of these ribbed fire-bars should
pass out through the sides of the furnace into air-tight casings in which
the spur wheels B', Figure 3, keyed on to the ends of the axles would
engage each other free from the destructive action of dust and flame.
The driving axle working the first or propelling spur wheel of the B
series must be closely glanded at the hole through which it enters the
air-tight box covering of the spur wheels in order to prevent the entrance
|The driving axle working the first or propelling spur wheel of the B
series must be closely glanded at the hole through which it enters the
air-tight box covering of the spur wheels in order to prevent the entrance
of air.
After the reduced iron is converted into steel by cementation the
mineral and carbonaceous matter intermixed with the powdered steel
may be separated by a winnowing arrangement, as herein-before
described, and may be freed from reduced copper or any other metal if
present by the use of the magnetic separator hercin-before mentioned.
The powdered steel may then be melted in any of the usual methods of
melting steel, but the cheapest way will be to work it into lumps by
means of a fluxing mixture of clay and sand with or without lime or
any other fluxing ingredient now used and without carbonaceous matter,
and to melt these lumps in a blast furnace constructed like the "duplex
furnace" described in the Specification of my Letters Patent, numbered
2930 of last year, entitled " Improvements in Furnaces." The fuel
chamber or chambers of this duplex furnace may be dispensed with and
carbonic oxide gas admitted through apertures in the sides of the
crueible, or boshes may be burned by means of hot blasts of air supplied
at such apertures of admission for the gas. The materials used for thus
effecting the consolidation of the steel powder into lumps must be so
gauged as regards their relative proportions as to resist fusion until the
temperature has reached the melting point of steel. The hearth of the
furnace will contain slag as at present, with molten cast steel under-
neath instead of pig iron, and this steel can be tapped off into pigs or
ingots of any desired shape or size. An intense melting and not a
reducing flame is needed for this operation, but it is better to so adjust
the volume of the blast as to avoid the admission of free oxygen
amongst the melting lumps.

page_text: by reductio Without fusion of the reduced metal or ferric
oxide or iron ore by incorporating it in a crushed state with carbonaceous
matter, consolidating it into lumps as described, and subjecting it to the
requisite reducing heat by means of a current of red hot carbonic oxide
gas passing amongst the consolidated lumps in the blast furnace, as
herein-before specified.
Secondly. Converting this spongy or powdered reduced iron into steel
by maintaining it at a red heat in admixture with powdered carbon for
a sufficiently long time to allow of the iron passing into the steely con-
dition through absorption of carbon by "cementation," as already
described.
Thirdly. Separating the reduced iron or steel powder from redundant
carbon or mineral impuritics by means of a winnowing or. blast
apparatus, or by means of a stream of water with or without the aid of a
magnetic separator, as described.
Fourthly. The fusion of this powdered steel by incorporating it with
lime and clay or other fluxing materials, by means of which it is con-
solidated into lumps and then melting it in a blast furnace without the
contact of solid carbon, as herein-before described.
Fifthly. The use of the various methods of effecting the consolidation
of the orc and carbonaceous matter into lumps by means of hydraulic
lime or cement, by common lime, by raw peat, or by clay with or
without coking of the lumps when bituminous coal dust is used, as
,herein-before specified.
Sixthly. Cooling down the temperature of the reduced iron or steel
either in a cylinder forming a continuation of the reducing furnace
vertically downwards, around which a current of cold air is made to
pass, or by transferring it whilst in a red hot state to air-tight metallic
drums in which to become cold by exposure to the air for the working
of this Invention, as described.
Seventhly. The use of the several furnace and other arrangements
herein-before described for the purposes of this Patent, and also the uso
of the methods of rendering the hot roasted ore more friable by sudden
immersion in water for the purposes of this Invention, and of all my

page_text: other patented processes for smelting ores, substantially as herein-before
specified.
In witness whereof, I, the said William Alexander Lyttle, have
hereunto set my hand and seal, this Twenty-seventh day of
February, in the year of our Lord 1875.