IMPROVEMENTS IN MANUFACTURE OF IRON
Year: 1856

page_text: LETTERS PATENT to Robert Mushet, of Coleford, in the County of
Gloucester, Metallurgist, for the Invention of "IMPROVEMENTS IN
MANUFACTURE OF IRON."
Sealed the 30th December 1856, and dated the 16th September 1856.
PROVISIONAL SPECIFICATION left by the said Robert Mushet at the
Office of the Commissioners of Patents, with his Petition, on the
16th September 1856.
I, ROBERT MUSHET, of Coleford, in the County of Gloucester, Metallurgist,
do hereby declare the nature of the said Invention for "IMPROVEMENTS IN
THE MANUFACTURE OF IRON," to be as follows (that is to say) :-
My said Invention consists of a mode of treating iron for the purpose of
making it malleable or more malleable, and solidifying the ingots or bars of it.
For these purposes I add to and mix with the iron a mixture of carbonaceous
matter and manganese. This mixture I add to the iron when it is in a fluid
or heated state, at the commencement, during, or at the end of the process
of decarbonizing or purifying cast iron, in order to convert it into malleable
iron.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Robert Mushet in the Great Seal Patent Office on the
16th March 1857.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, ROBERT
MUSHET, of Coleford, in the County of Gloucester, Metallurgist, send greeting.
WHEREAS Iler most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Sixteenth 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, Ier heirs and successors, give and grant unto me, the said
Robert Mushet, my executors, administrators, and assigns, Her special licence
that I, the said Robert Mushet, my executors, administrators, and assigns,
or such others as I, the said Robert Mushet, my executors, administrators,
and assigns, should at any time agree with, and no others, from time to time
and at all times thereafter during the term therein expressed, should and
lawfully might make, use, exercise, and vend, within the United Kingdom
of Great Britain and Ireland, the. Channel Islands, and Isle of Man, an
Invention for "IMPROVEMENTS IN THE MANUFACTURE OF IRON," upon the condition
(amongst others) that I, the said Robert Mushet, my executors or adminis-
trators, 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 Robert Mushet, do hereby declare the
nature of my said Invention, and in what manner the same is to be performed,
to be particularly described and ascertained in and by the following state-
ment:-
When cast iron, including grey and white pig iron and refined metal, has
been decarbonized or purified by forcing air through or amongst its particles,
either in the manner described in the Specification of the Letters Patent dated
the Fifteenth day of September, One thousand eight hundred and fifty-five,
granted to Joseph Gilbert Martien, or in any other convenient manner, with a
view to convert it into malleable iron, and when ingots or masses of iron thus
decarbonized or purified are formed by pouring or running the metal when
in a heated or fluid state into moulds, it is found that the ingots or masses of
iron thus produced are usually more or less porous, spongy, or cellular in
their structure, and are also frequently crystalline in their grain or fracture.

page_text: When the ingots or masses of this decarbonized or purified. iron are
subjected in a heated state to the action of rollers or hammers, in order to
extend them into bars, it is generally found that these bars possess several
defects. They sometimes crack to pieces, or have numerous cracks along their
edges, and when the bars do not exhibit these cracks they are, on the other
hand, often "cold short" or brittle.
The object of my Invention is to lessen or remove these defects as much as
practicable, and my Invention consists of a mode of treating this decarbonized
or purified iron for the purpose of making it malleable or more malleable, and
solidifying the ingots or bars of it.
For these purposes I add to and mix with the iron a mixture of car-
bonaceous matter and manganese. This mixture I add to the iron when it is
in a heated and fluid state, at the commencement, during, or at the end of the
process of decarbonizing or purifying cast iron, in order to convert it into
malleable iron, or it may be added partly at one stage or part of the process,
and partly at another stage.
In order to obtain the mixture of carbonaceous matter and manganese in a
convenient form for the purposes of my Invention, I prefer to prepare it as
follows I take the manganese of commerce, and by preference the common
black oxide of manganese so extensively used by glass makers, bleaching
powder manufacturers, &c., &c., preferring also to use that which is the purest
and most free from earthy matters. In an iron cauldron, set over a fire, I
place a given weight of pitch, and to this, when melted, I add, by stirring in,
an equal weight of calcined or uncalcined oxide of manganese, reduced to a
fine powder by stamping, crushing, or grinding, and when well mixed with
the pitch, I pour the liquid mass upon a cold stone or other suitable surface,
where in cooling it becomes a hard brittle substance. Or, I mix, in a similar
manner, a given weight of oxide of manganese, with an equal weight of coal
tar or resin; charcoal may be added in place of a portion of the pitch or
coal tar, or other tar or resin, in order to economize the pitch, tar, or resin,
but I prefer to use pitch or resin without charcoal. I sometimes also take
bituminous coal, as free as possible from sulphur, and having pulverized
it, I mix a given weight of it with an equal weight of calciued or uncalcined
oxide of manganese finely pulverized, and I then subject the mixture thus
formed, enclosed in an oven or other close vessel or chamber, to the action of
a heat sufficient to convert the said mixture into a compound coke more or
less compact.
I do not claim these methods of making any of the mixtures of carbonaceous

page_text: matters with oxide of manganese above mentioned; and the mixture of car-
bonaceous matters and manganese intended to be used for the purposes of my
Invention may be prepared in any other manner which may be deemed
convenient, and the proportions of the carbonaceous matters and manganese
may be varied; but I have herein-before mentioned the nature as well as
proportions, and also the modes of mixing the carbonaceous matters and
manganese which I prefer to adopt in practice. In whatever manner the
compound or mixture of carbonaceous matter and manganese may have been
produced, I take it, when cold, and reduce, pulverize, or crush it into a coarse
powder, or into small pieces, in order to facilitate the mixture of it with the
fluid and heated purified iron.
When the compound or mixture of carbonaceous matter and manganese is
to be added at the commencement of the purifying process, I place in the
purifying furnace or vessel a quantity of the above compound mixture, equal
by weight to from one-fiftieth to one-tenth of the weight of fluid cast iron, to
be run into the purifying vessel, and I then run in the fluid cast iron, and
proceed to purify it by means of currents of air, either as described in the said
Specification, or in any other convenient manner. When the compound
mixture of carbonaceous matter and manganese is to be added to the fluid
cast iron during the process of purifying or decarbonizing the cast iron, I
introduce through a suitable opening in the top or side of the purifying vessel
or furnace a quantity of the crushed or broken compound or mixture of
carbon and manganese, equal by weight to from one-fiftieth to one-tenth of the
weight of the cast iron contained in the purifying vessel or furnace, and in
this case I prefer so to introduce it after the slag or scoria of the iron
has been thrown off at that stage of the air-purifying process called the
eruption.
Lastly, when the cast iron has been purified or decarbonized as much as it
is intended it should be, and the purifying process is completed, the mixture
or compound above-mentioned may be introduced into the purifying furnace or
vessel. In this case, I add to the purified fluid mass of iron from one-fiftieth
to one-tenth of its weight of the crushed or broken compound or mixture of
carbonaceous matter and manganese, which I introduce through a suitable
opening in the top or sides of the purifying furnace or vessel, and I prefer to
use a purifying furnace or vessel which, by varying its position or otherwise,
will admit of the blast being withdrawn without permitting the melted iron to
enter into and fill up the tuyere openings.
The quantities or proportions of the mixture of carbonaceous matter and

page_text: manganese used in any of these ways may be varied, and a portion of it may
be introduced at each of the three stages of the process of decarbonizing or
purifying the iron which I have mentioned. I prefer to operate thus upon a
large mass, a quantity of purified or decarbonized cast iron, in order that after
the blast of air has been withdrawn and a mixture or compound such as I
have described has been introduced into it, the fluid mass of iron may, by
reason of its great mass, retain its fluid state and temperature as long as
practicable.
After thus introducing the compound of carbonaceous matter and oxide of
manganese, I allow the purified iron and the compound mixture thus intro-
duced to remain in the purifying vessel or furnace as long as possible without
endangering its passing into the solid state, in consequence of its diminished
temperature, and I then run off and pour the purified iron in the usual
manner into suitable moulds; the ingots or masses thus obtained may then
be subjected to the action of hammers or rollers in the ordinary manner,
in order to extend them into bars, rods, or sheets of any desired form or
description.
When I desire still further to improve the quality of the iron, I tap and
run off the purified or decarbonized cast iron from the purifying furnace or
vessel into pots similar to ordinary cast-steel melting pots, which I previously
cause to be brought to an intense white heat in an ordinary furnace, such as
that used for melting cast steel. These melting pots, when filled or partly filled
with the fluid purified cast iron, I then cause to be quickly returned into the
melting furnace from whence they were taken, and a quantity of the mixture
or compound of carbonaceous matter and manganese, such as I have herein-
before described, equal by weight to about one-twentieth part of the weight of
the purified cast iron contained in each melting pot, is to be introduced or put
into each such melting pot. The pots are then to be surrounded in the
melting furnace with fresh fuel, in the manner usually practised by steel
manufacturers, and when the fuel has burned away, the pots are to be with-
drawn, and the fluid contents are to be poured into suitable ingot moulds in the
usual manner.
Having thus particularly ascertained and described the nature of my said
Invention, and the manner in which the same is to be performed, I hereby
declare that what I claim as my said Invention is, the addition and admixture
of a compound or mixture of carbonaceous matter and manganese to and with
iron purified or decarbonized by air being caused to pass through it whilst it is
in a heated and fluid state, at the commencement of, or during, or at the end of

page_text: such decarbonizing or purifying process, for the purpose of making such iron
malleable or more malleable, and solidifying the ingots or bars of it, and
improving its quality.
In witness whereof, I, the said Robert Mushet, have hereunto set my
hand and seal, this Eleventh day of March, in the year of our Lord
One thousand eight hundred and fifty-seven.
Witness,
MAXWELL MUSHET,
Coleford, Gloucestershire.
JOHN LOCKE, Clerk to Mr. Rob Mushet,
Coleford, Gloucestershire.
ROBT MUSHET. (L.S.)