AN IMPROVEMENT OR IMPROVEMENTS IN THE MANUFACTURE OF IRON
Year: 1856

page_text: LETTERS PATENT to Thomas Callender Hinde, of Birmingham, in the
County of Warwick, Merchant and Manufacturer, for the Invention of
66 Ax TurnAZEN OD IZDRAVEHEARTURE OF TRON"
Sealed the 28th November 1856, and dated the 18th September 1856.
PROVISIONAL SPECIFICATION left by the said Thomas Callender Hinde
at the Office of the Commissioners of Patents, with his Petition, on the
18th September 1856.
I, THOMAS CALLENDER HINDE, of Birmingham, in the County of Warwick,
Merchant and Manufacturer, do hereby declare the nature of the said Inven-
tion for "AN IMPROVEMENT OR IMPROVEMENTS IN THE MANUFACTURE OF IRON,"
to be as follows:-
My Invention consists of the method of reducing and fluxing iron ore,
herein-after described. In place of the treatment to which it is subjected in
the blast furnace, according to ordinary method of manufacture, I mix the
ore with carbonaceous matter, and heat it in a close furnace from which air
is carefully excluded. By this treatment the carbonization or reduction or
partial reduction of the ore is effected. I afterwards treat the carbonized
or reduced ore in the blast furnace so as to flux the same, and effect the
separation of the metal from the earthy matter of the ore. The blast furnace
I employ is much shorter than the ordinary blast furnace, as the carbonization

page_text: or reduction has been effected or partially effected before the ore is put into
the blast furnace. By this method of manufacture, the treatment in the blast
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Thomas Callender Hinde in the Great Seal Patent Office on
the 17th March 1857.
TO ALL TO WHOM THESE PRESENTS SHALL COME, J, THOMAS
CALLENDER HINDE, of Birmingham in the County of Warwick, Merchant and
Manufacturer, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Eighteenth day of September, in the year of our
Lord One thousand eight hundred and fifty-six, in the twentieth year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me, the
said Thomas Callender Hinde, Her special licence that I, the said Thomas
Callender Hinde, my executors, administrators, and assigns, or such others as
I, the said Thomas Callender Hinde, my executors, administrators, and
assigns, should at any time agree with, and no others, from time to time and
at all times thereafter during the term therein expressed, should and lawfully
might make, use, exercise, and vend, within the United Kingdom of Great
Britain and Ireland, the Channel Islands, and Isle of Man, an Invention for
"AN IMPROVEMENT OR IMPROVEDENTS IN THE MANUFACTURE OF IRON,"
upon the
condition (amongst others) that I, the said Thomas Callender Hinde, 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 per-
formed, 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 Thomas Callender Hinde, do hereby
declare the nature of the said Invention, and in what manner the same is to
be performed, to be particularly described and ascertained in and by the
following statement thereof, that is to say :--
In carrying out my Invention, I take the red oxides of iron or the
hæmatites in the raw state; but when I employ carbonates, or any other ore
which may contain sulphur, phosphorous, or other impurities that can be
volatilized. I prefer to calcine the ore; I then place the ore in a furnace,

page_text: which may be constructed as herein-after described to exclude the air, in
alternate layers with charcoal, coke, or other carbonaceous matter. The oro
may either be crushed fine or merely broken into pieces of a moderate size,
say, three inches in diameter, but the size of the ore is not an essential
condition of the process. The ore and carbonaceous matters being thus inter-
stratified, and a covering of some incombustible material, as fire tiles, sand,
or the like, placed over the top to prevent the combustion of any of the
included carbonaceous matter, I apply fire externally, gradually getting the
furnace up to a full white, but not to a melting heat, that is, to as high a heat
as can be safely applied without melting the materials. The time during
which the ore requires to be subjected to this heat will vary with its nature and
compactness, and the consequent ease with which the carbon can penetrate
it, but for the majority of ores two days' exposure to a full heat will be found
sufficient. As the affinity of the carbon for the oxygen of the ore is developed
by the temperature of the furnace during the descent of the ore, the reduction
of the ore takes place, and the last portion of oxygen being finally withdrawn,
it now remains metallic iron in a spongy mass, containing the earthy portions of
the original ores mechanically mixed with it. In this state the iron is malleable;
if broken up much of the earthy matter will fall out from its pores, and it
may even be welded.
It is advisable, however, to carry on the carbonization of this sponge of
metallic iron still farther, which may be done at pleasure by continuing it a
longer period in the furnace, till it becomes either of a strong steely nature,
or with more carbon assumes the character of grey forge pig iron, and, finally,
by a still more prolonged cementation with the carbon, it imbibes so much as
to be a perfectly grey foundry iron. The ore being thus converted into a
mechanical mixture of earthy matter and metallic iron of such a degree of
carbonization or greyness as the different uses for which it is intended
may require, it is now taken to the blast furnace, but the reduction and
carbonization having been already completed, there remains nothing more to do
than to melt the converted ore with a suitable proportion of limestone or other
flux. The metallic iron contained in the converted ore trickles down to the
hearth, while the limestone, seizing the earthy residuum, fluxes with it, and forms
the cinder, which is allowed to run off in the usual manner; the iron also is
tapped out at the bottom and runs into the moulds provided for it, as in the
ordinary way of working. The process in the blast
so much shortened, that the high furnaces now in
farnace resembling a common foundry cupola, of
height, being sufficient. Instead of a blast or cupola
furnace by this means is
use are not necessary, a
about 12 to 14 feet in
furnace, a reverberatory-

page_text: be used,
furnace, or what is commonly called by founders an air furnace, may
and with great advantage, to the quality of the iron for some purposes, as in
this description of furnace the heat being produced by the flame and rever-
beration from the roof, the contact of the iron with the fuel, which generally
contains more or less injurious impurities, is prevented, and the only mixture
to be charged with the converted ore is the limestone or other flux, which will
of course be charged into the furnace with it, and provision made, as before
named, for the running off of the cinder and tapping out the iron.
Another description of furnace by which the same result of preventing the
contact of the fuel may be arrived at is by an arrangement similar to the
small flues of a brick kiln, the said flues being placed outside the furnace,
into which the converted ore is charged, and proper flues made into the
furnace; the flame and radiated heat alone pass into the furnace through
the flues, and thus melt the converted ore and flux, the separation of the iron
and cinder taking place, as in the blast or cupola furnace.
Another method by which the reduction and carbonization of the ore and
the subsequent melting may all be performed in the same furnace is to con-
struct the furnace with the external flues so arranged, that when the ore has
descended nearly to the bottom in fit state for the melting, as before described,
the heat is so much increased that the melting takes place within the furnace,
the whole of the heat required for the two processes of reduction and car-
bonization and of melting being in this instance generated and applied
externally, excepting of course the heat necessarily evolved in the furnace by
the chemical combination of the oxygen of the ore with the interstratified
carbon, and which is in all cases produced and materially assists the external
heat in raising the temperature of the contained material. In this case it may
be advisable to charge the limestone down a portion of the furnace, bricked off
or kept separate from the other materials, reaching down to the point where
the melting takes place, and open at the bottom so that the limestone does not
mingle with the other materials until it is required for fluxing the earthy
matter.
Another plan of combining the two processes consists in constructing the
carbonizing furnace in a cylindrical or square form, or with more or less
deviation from these forms, and then in so placing the cupola or reverberatory
or other form of furnace intended for the melting operation near to the bottom
of the carbonizing furnace, that the converted ore may slide out of the car-
bonizing furnace in its already white hot state into the cupola or reverberatory
furnace, and be there melted as before. Access of the air to the carbonizing
furnace may be prevented by the aperture through which the converted ore

page_text: slides into the melting furnace being closed with a stopper of fire clay or other
suitable material; or it may be prevented by the continuous descent of the
converted ore; there being no draught through the carbonizing furnace by
reason of the mode in which the materials are charged, there is of course
but slight tendency in the air to penetrate into the materials. The carbonizing
furnace may be constructed in any form which will answer the requisites of
burning the fuel with the greatest economy, generating a sufficient heat for the
process without melting the ore, and of being continuous in its operation, that
is, constantly receiving and discharging its burden of materials without ever
stopping except for repairs. The construction I recommend as well adapted
to secure these objects is a building of an oblong form, the length being
immaterial, in height from 18 to 25 feet above the level of the ground,
according to the nature of the ore and the time it requires for reduction and
carbonization, and about 9 feet in the clear internally, but I divide it into two
sections lengthwise by a row of flues running up the middle; these are to
be heated by a fire grate of proper area at each end. The two outside walls
are to be heated by flues from the outside in a similar manner, but in the case
of the two outsides the fire grates may either be placed lengthwise with the
furnace and parallel with the centre fire grates; or instead of two large grates
a series of smaller ones may be placed endways to the furnace, each one of
these smaller grates only supplying one, two, or more of the flues which run
up the two outside walls of the furnace. The bottom of the furnace is sunk,
say, 8 feet below the level of the ground, and a roadway provided around it,
which may be arched over or covered with iron plates (so as to give proper
access to the fire grates which are on the ground level), and on this roadway
trams may be laid, on which the waggons to remove the converted ore may
run. Along both sides of this sunk part of the furnace are arches, by which
access is gained to the interior, and above these arches a provision is made by
building in the walls iron sockets for the workmen to drive what are called
scaffolding bars. At the first starting of this furnace it is advisable to fill the
sunken part as high as or rather higher than the scaffold bars with coke dust,
or other non or badly conducting substances, as of course no carbonization or
reduction is intended to take place in this portion, its purpose being simply for
the cooling and discharge of the materials. The ore and carbonaceous matter
being charged in alternate layers and the fires put in operation, the oxygen of
the ore consumes a definite proportion of the carbonaceous matter, the
materials commence sinking, and fresh layers are constantly put on so as to
keep the furnace full. The time required for the carbonization may be known
by having trial holes from the exterior and taking out small portions of the

page_text: ore, when its appearance will readily indicate the extent to which the car-
bonization has proceeded, the iron in it becoming perfectly metallic as soon as
all the oxygen of the ore has been withdrawn by entering into combination
with the carbonaceous matter interstratified with it. As soon, therefore, as
the ore is seen to have become sufficiently converted, the coke_dust or other
material under the scaffolding bars is raked out, the scaffold bars, which of
course supported the materials above, are drawn, and a sufficient quantity of
them descends to fill up the vacant space; the scaffold bars are again driven
in so as again to carry the materials above; the converted ore underneath is
raked out and placed in the waggons for removal to the melting furnace; the
apertures are carefully closed by building up loose bricks and stopping up with
sand or clay, or iron closings may be fixed, if preferred, though more ex-
pensive; the scaffold bars are again immediately drawn, so as to let down the
converted ore to the bottom of the furnace. The apertures through which the
bars have been withdrawn are stopped up, and as soon as the furnace shall
have again converted enough ore to fill the bottom space the bars are again
driven in, the converted ore removed, the apertures bricked up, and the bars
again withdrawn, and their socket holes stopped; the object of thus letting
the bottom part of the furnace be constantly full being twofold; first, to
prevent any chance of air gaining access; and next, that the converted ore may
be partially cooled before the workmen draw it, by remaining some time in this
lower part of the furnace below the action of the heat from the flues. From
the mode of operation adopted in this process it will be seen that great com-
mand is given to the manufacturer, enabling lim to secure precisely the class
of iron required.
Another important advantage consists in the fact, that the heat being
applied from the outside without contact of the fuel with the ore, any
inferior or sulphureous coal can be used outside, while the amount of carbon
required inside for reduction and carbonization being only a very small
portion of the total consumption of fuel, the manufacturer is enabled to use
charcoal or charcoal dust for this portion of the process, and thus secure the
quality of charcoal iron at a very trifling additional outlay to that made by
coke or coal.
Having now described the nature of my said Invention, and the manner of
carrying the same into effect, I wish it to be understood that I do not limit
myself to the precise details herein described, as the same may be varied
without departing from the nature of my Invention; but I claim as my Inven-
tion the improvement or improvements in the manufacture of iron herein-
before described, that is to say, manufacturing cast iron by first effecting the

page_text: reduction of the iron without fusion, and afterwards fluxing the reduced oro
as a separate process, and, by preference, in a separate furnace, as herein
described.
In witness whereof, I, the said Thomas Callender Ilinde have hereunto
set my hand and seal, this Sixteenth day of March, in the year of
our Lord One thousand eight hundred and fifty-seven.
Witness,
GEORGE SHAW.
THOMAS CALLENDER HINDE. (L.S.)