ROVEMENTS IN THE MANUFACTURE OF CAST IRON, MALLEABLE IRON, AND STEEL
Year: 1865

page_text: LEITERS PATENT to Nicholas Korshunoff, of Birmingham, in the County
of Warwick, Civil Engineer, for the Invention of IMPROVEMENTS IN THE
MANUFACTURE OF CAST IRON, MALLEABLE IRON, AND STEEL,"
Sealed the 6th March 1866, and dated the 26th September 1865.
PROVISIONAL SPECIFICATION left by the said Nicholas Korshunoff
at the Office of the Commissioners of Patents, with his Petition, on
the 26th September 1865.
I, NICHOLAS
:
ORSHUNOFF, of Birmingham, in the County of Warwick,
Civil Engineer, do hereby declare the nature of the said Invention for
"IMPROVEMENTS IN THE MANUFACTURE OF CAST IRON, MALLEABLE IRON, AND
STEEL," to be as follows:
My Invention consists of the improvements herein-after explained in the
manufacture of cast iron and in treating cast iron for the manufacture therefrom
of malleable iron and steel.
My improvements in the manufactureof castiron consist in introducing nitric
acid,or chloric acid,or other acid, which on being heated liberates oxygen intothe
blast employed in supporting the combustion in the blast or smelting furnace,
or into a blast forced through the melted metal collected at the bottoin of the
furnace. By the introduction of the said acids the iron is in partdecarbonized,
and a high temperature is produced in the furnace; the said acids may be
used either with hot or cold blast, and in conjunction with gas or steam.:
[Pri

page_text: My improvements in treating cast iron for the purpose of manufacturing
therefrom malleable iron or steel consist in the employment, in the manner
herein-after explained, of nitric acid, or chloric acid, or other acid rich in
oxygen in the form of blast as herein-before described, as well as combined
with potash, or soda,or lime, or other base. I take the salts formed by the com-
bination of the said acids with the said bases,and add them to the melted cast
iron in the puddling or other furnace or apparatus in which the said cast iron
is being converted into malleable iron or steel, the blast containing the said
acids being at the same time passed through the melted metal. By the use
of the said salts a very fusible slag is produced, and the conversion of the
cast iron into malleable iron or steel is rapidly effected; the metal is at the
same time purified.
The quantity of acid or salt employed must vary with the quality of the
iron operated upon, and must be such that the oxygen of the acid is sufficient
to oxidise the carbon, sulphur, phosphorus, and silicon contained in the cast
iron when the said cast iron is to be made into malleable iron, and only
sufficient to partially effect the oxidation of the carbon when cast iron or steel
is being manufactured. The exact quantity can only be determined by an
analysis of the iron operated upon.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Nicholas Korshunoff in the Great Seal Patent Office on
the 26th March 1866.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, NICHOLAS
KORSHUNOFF, of Birmingham, in the County of Warwick, Civil Engineer,
send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent,bearing date the Twenty-sixth day of September, in the year of our Lord
One thousand eight hundred and sixty-five, in the twenty-ninth year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me, the
said Nicholas Korshunoff, Her special licence that I, the said Nicholas
Korshunoff, my executors, administrators, and assigns, or such others as I,
the said Nicholas Korshunoff, 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 Mau, an Invention for "IMPROVE-

page_text: MENTS IN THE MANUFACTURE OF CAST IRON, MALLEABLE IRON. AND STEEL," upon
the condition (amongst others) that I, the said Nicholas Korshunoff, 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 Nicholas Korshunoff, do hereby declare
the nature of the said Invention, and in what manner the same is to be per-
formed, to be particularly described and ascertained in and by the following
statement thereof, that is to say :-
My Invention consists of the improvements herein-after explained in the
manufacture of cast iron, and in treating cast iron for the manufacture of
malleable iron and steel.
My improvements in the manufacture of cast iron consist in introducing
nitric acid, or chloric acid, or other acid, which on being heated liberates
oxygen into the blast employed in supporting the combustion of fuel in the
blast or smelting furnace, or into a blast forced through the melted metal
collected at the bottom of the furnace. By the introduction of the said acids
the iron is in part decarbonized, and a high temperature is produced in the
furnace; the said acids may be used either with hot or cold blast, and in con-
junction with gas or steam.
My improvements in treating cast iron for the purpose of manufacturing
therefrom malleable iron or steel consist in the employment, in the manner
herein-after explained, of nitric acid, or chloric acid, or other acid rich in
oxygen in the form of blast as herein-after described, as well as combined
with potash, or soda, or lime, or other base. I take the salts formed by the
combination of the said acids with the said bases, and add them to the melted
cast iron in the puddling or other furnace or apparatus in which the said cast
iron is being converted into malleable iron or steel, the blast containing the
said acids being at the same time passed through the melted metal. By the
use of the said salts a very fusible slag is produced, and the conversion of
the cast iron into malleable iron is rapidly effected; the metal is at the same
time purified.
The quantity of acid or salt employed must vary with the quantity of the
iron operated upon, and must be such that the oxygen of the acid is sufficient
to oxidise the carbon, sulphur, phosphorus, and silicon contained in the cast
iron when the said cast iron is to be made into malleable iron, and only

page_text: sufficient to partially effect the oxidation of the carbon when cast iron or steel
is being manufactured. The exact quantity can only be determined by an
analysis of the iron operated upon.
Having explained the nature of my Invention, I will proceed to describe,
with reference to the accompanying Drawings, the manner in which the same
is to be performed.
My improvements in the manufacture of cast iron consist in the intro-
duction of nitric acid, chloric acid, or other acids which on being heated
evolve oxygen, and also when required introducing hydro-acids or other
materials containing hydrogen, such as oils or other liquid hydrocarbons.
As the principal object in the improvement of cast iron consists in the
separation as far as possible of the impurities contained in the metal, it is
first necessary to ascertain the quantity and quality of these impurities, <fter
which it is easy to decide which acid, or mixture of acids, and what quantity
will be required for separating the impurities. As all cast iron contains more
or less non-metallic elements, the employment of any hydro-acids or materials
abounding in hydrogen or the salts of hydro-acids in due proportion will purify
the metal entirely, or nearly so, from the said non-metallic elements. For
example, if hydrofloric acid or other hydro-acid is passed through melted metal
the acidis decomposed,and at the moment of its decomposition the hydrogen
does not combine with the metal, but with the non-metallic elements forming
the impurity of the metal which are evolved in the form of gases, and the
metal is thus purified. In those cases where the metal contains earthy metals
I add fluor spar (floride of calcium) in due proportion, when silicates of the
earthy metals are formed and fluor silicates which are evolved in the form of
slag. When the metal contains aluminum and silicon, or generally in case
of slags difficult of fusion, I add a combination of the acids before mentioned
with bases which will produce a liquid slag, which combination of acids and
bases I enclose in a case or covering made of thin sheet iron; after this pre-
liminary cleansing I proceed to the converting operation, using oxygen acids.
This operation is performed in casting ladles, casting pots, blast furnaces,
reverberatory or other furnaces and apparatus. When I employ casting ladles
and casting pots so as to operate upon a small quantity of cast iron, I make
use of a hand apparatus constructed in either of the ways represented in
Figures 1 to 8, both inclusive, of the Drawing for introducing the acid into
the cast iron.
Figure 1 represents a vertical section of one of the hand apparatus. a is
an iron tube enamelled inside provided with a closed bottom, holes being
made near the said bottom. The upper end of the tube a has a screw for

page_text: receiving a cap or cover, and the lower end is covered with a tube c made of a
mixture of fire-clay and blacklead. Inside the tube a is another thin metal
tube benamelled, having a closed bottom. All the parts of this apparatus, as
well as those herein-after described, must be made of or coated with such
materials as are not affected by acids; in the central tube the acid to be
supplied to the cast iron is placed. In using the apparatus, the tube c is
heated and plunged into the fused cast iron, wheu the acid in the form of
steam or vapour passes over the open top of the tubeb, down the tube a, and
escapes into the cast iron through the holes in the bottom of the tube c.
At
Figure 2 represents a vertical section of another hand apparatus. a is the
external reservoir connected with the closed bottom of the tube; b, internal
reservoir for containing the liquid acid, which liquid acid is introduced when
the cover e is screwed off. The internal reservoir b is connected with another
tube c; also with a closed bottom, into which is inserted a tube d with a
funnel-shaped top, which lies with its collars on the sides of the reservoir,
forming an annular opening; this last tube does not reach the bottom.
the end of the external tube there is another, marked ƒ, made of fire-clay, the
openings of which, as seen in the Drawing, are connected with the interior of
the tube c. The tubes of fire-clay are made from dry clay according to the
well known method. I prefer using pure fire-clay with an admixture of
blacklead. The best forms of the clay tubes c and are shown separately in
Figure 3. When the tube is heated the acid, steam, or vapour rises
through the liquid in the reservoir, and passes between the internal and
external reservoirs to the tube f, when it escapes through the holes therein to
the cast iron.
Figure 4 is a vertical section of another hand apparatus, consisting of the
reservoir a connected with the tube b. The bottom of the reservoir has a
conical valve seat c, upon which the conical valve d works, the rod of which
valve passes through a stuffing box, and terminates in a handle c, by which
the valve can be raised or lowered. When the valve d is raised the acid
from the reservoir a can drop on gravel or pumicestone g in the tube b. A
graduated dial may be placed under the handle of the valve for indicating the
quantity of liquid passing from the reservoir, a pointer on the said handle
traversing the said dial. Before using this apparatus, the end of the clay
tube f is heated red hot, and then used for converting cast iron into steel or
semi-steel, the heated sides of the tube causing the steam or acid vapour to
pass out at the lower openings of the tube. The size of the valve and other
parts of the apparatus is regulated according to the use to which the
apparatus is to be put, but must be such that the liquid will pass out in

page_text: drops or in a thin stream in order to produce a pressure of steam or vapour
in the tube equal to that of the column of converting metal.
Figure 5 represents another apparatus differing somewhat from that last
described. This apparatus has two pipes joined to the reservoir, the liquid
passing through an open valve, and dropping on heated gravel or pumicestone
placed in the middle pipe of the apparatus to evaporate. The acid vapour
space between
passes through holes at h at the top of the inner pipe to the
the outer and inner pipes, from which the vapour will pass out at the lower
aperture of the outer tube to the melted metal.
Figure 6 represents a vertical section of another hand apparatus. It is the
reservoir; b, liquid; c and d are pipes with closed bottoms connected with
the reservoir. The top of the middle pipe is fitted with a valve opening
downwards, the hollow rod of which valve passes through a stuffing box and
is connected with a lever jointed at e to the top of the reservoir; the other
end of the lever is held down by a coiled spring and piston in a tube at f, the
pressure of which spring is regulated by the screw nutg. The cover of the
reservoir is fitted with feeding holes and stopper. The acid having been
introduced into the reservoir a, the end f³ of the apparatus is heated red hot;
the nut g is turned so as to depress the lever and open the valve; the acid
will now drop on to the gravel or pumicstone in the heated pipe, and be
evaporated. The acid vapour passes through holes at i near the top of
the pipe c to the space between the outer and inner pipes, as well as
through the hollow valve rod to the upper part of the reservoir, and will
press upon the piston and spring at f, and if the generation of the acid vapour
is too rapid the lever will be raised and the valve closed, and the acid will no
longer pass to the heated tube. When the pressure of the acid vapour
diminishes the valve is reopened, and the supply of acid to the heated
pipe again continued.
Instead of the arrangement described for opening and closing the valve,
the reservoir may be provided with a cover of thin platina or other elastic
material not affected by acids; the said cover may have a convex or other
form, upon which the pressure of the vapour of acid can readily act; the rod
of the valve is connected with the cover. As the pressure of the vapour of
acid upon the cover is greater or less, so the cover will be deflected or bulged
more or less, and the valve raised from or lowered upon its seat; the amount
of acid passing from the reservoir is thus regulated. By means of an
ordinary graduated water gauge the quantity of acid in the reservoir may be
ascertained from time to time.
Figure 7 represents another hand apparatus with a cylindrical reservoir, the

page_text: bottom of which is fitted with a pipe and tap b for feeding the interior pipe
of the apparatus. This apparatus has a pressure gauge by which the action
of the apparatus can be regulated.
Figure 8 represents a vertical section of another hand apparatus with a
globular reservoir, in which the flow of the liquid changes very little the
horizontal level of the liquid. The acid is introduced into the reservoir by
the funnel c, the passages to the reservoir being opened and closed by the
raising and lowering of the said funnel. After the introduction of the acid,
and before the funnel is lowered, the said funnel is connected by a union
joint with an air condenser, by which air is condensed in the reservoir. This
having been done the funnel is lowered and the passage in the reservoir
closed, and the union joint removed from the funnel. By means of the
condensed air above the liquid in the reservoir the issuing of the acid vapour
is regulated.
In manufacturing or converting cast iron in the blast furnace according to
my Invention I proceed as follows:-When the fused metal and slags have
accumulated in the crucible or bottom of the furnace, the silicates or slags
floating upon the top of the fused metal are run out or removed by a suitable
channel into waggons, or utilized by being moulded into bricks, tubes, panels,
plates, or other articles; or the slags may be broken up and pulverized by
means of suitable machinery,and the powder produced used either by itself or
in admixture with other materials for the making of a cheap glaze for glazing
bricks or for other purpose where a cheap glaze is required. After the
renoval of the slags from the melted metal in the crucible or bottom of the
furnace the blast is shut off, and the valve of the acid retort or generator
containing the steam or vapour of acid or acids is opened,and the said vapour
of acids permitted to enter the blast furnace, and operate upon and purify the
melted metal therein. The vapour of acid or acids from the retort or
generator passes along a pipe connected with channels arranged by the sides
or the bottom of the bed or crucible of the furnace. These channels are made
of fire-clay or cast iron glazed internally, and square or other figure in section.
They are joined together by sockets luted together in the usual way. I prefer,
however, to cover the joints with a glaze by means of a brush, or with boiled
oil,and then dry glaze dusted over; or instead of dry glaze common salt may,
be used mixed with borax or other glazes. The fusion of these glazes may
be made with hydrogen gas or with common gases in combination with a
blast of air. The channels described at the sides or bottom of the crucible
of the blast furnace for conveying the acid vapour to the fused metal are
provided with tuyeres having valves, the said tuyeres and valves being con-

page_text: structed in the manner represented in Figures 9, 10, 11, 12, and 15 of the
Drawings. On opening the valve of the acid retort or generator the acid
vapour therefrom enters the channels at the sides or bottom of the furnace
and when the pressure of the steam or vapour of acids is greater than
that of the column of metal and remaining slags and valve springs of the
tuyeres, the said valves of the tuyeres will be opened, and the converting
process begins. The steam or vapour of acids passing through the fused metal
will produce a violent boiling, with a strong flame and sparks, and the process
is conducted to the degree or result desired, which may be judged by the
quantity of acids used, or by the samples of iron taken, or even by the
experience of the workman.
After the converting process has been carried to the desired extent the
metal is run into casting ladles, or into ingots, or other moulds in the usual
way. I prefer, however, to regulate the issue of the metal by means of a
tapping bar covered with fire-clay, similar to that employed in brass casting,
the said tapping bar entering more or less into the aperture of the blast
furnace. By this means the funnels passing into the moulds will be full of
the metal, thus preventing a current of air and the formation of unsound
castings. I prefer during the flow of the metal into the ingot or other
moulds to stir the surface with wooden poles. By the action of the melted
metal upon the poles they are decomposed, and the gases evolved combine
with the oxygen of the metal and the air above the metal. Instead of wooden-
poles, one of the hand apparatus herein-before described may be used, the
apparatus containing a volatile oil, and evolving a gas or vapour rich in
carbon.
When the blast of the furnace is of a pressure equal to the pressure
of the column of fused metal, slag, and springs of the acid tuyeres, I shut
off the said blast from the furnace as before described, and send it through
the generator or acid retort, and thus convey the combined blast and acid to
the fused metal on the bed of the furnace. This mode of manufacturing in
common blast furnaces requires attention and experience, in order to obtain
a certain quality of metal, as the quality of cast iron in blast furnaces is very
irregular under apparently like circumstances.
In carrying my Invention into effect when reverberatory or other furnaces
are used for re-melting cast iron of one or several kinds, with or without old
cast iron, the process may be made more regular, the chemical composition of
the metal being first ascertained. The acid vapour, either with or without
blast of air, and either with or without a base, is passed into the cast iron in
the puddling or other furnace, for the purpose of converting the said cast iron
into malleable iron or steel, in the manner described with respect to the blast

page_text: furnace; or the acid vapour may be passed into the iron in the puddling
furnace through a hollow rabble or puddling tool. For the conversion and
re-melting of the metal in reverberatory furnaces, I construct channels at
the sides or bottom similar to those described with respect to blast furnaces.
I also so arrange the furnaces that the re-melting furnace is higher than
the converting furnace, so that the metal from the former may run into the
latter.
In converting cast iron I prefer to use cast iron containing as little as
possible of foreign admixtures. As the ordinary cast iron is cast in sand
moulds, it is subject to the chemical and mechanical influence of the ground,
which injures its quality; I therefore prefer to use cast iron which has been
cast in metal moulds, or moulds made of or covered with some material not
injurious to the metal. In using metal moulds they are placed on trucks on
rails and brought on one side of the furnace, and when filled with metal
conveyed to the other side. When the metal is solidified in moulds intended
for foundries, it must be covered with sawdust mixed with clay or other
suitable material, and if possible with charcoal or pure anthracite coal, or the
latter may be used alone, which improves the surface of the cast iron.
The acids used in the manufacture and conversion of cast iron may be
made before or during the manufacture. In the latter case I make use of
the waste heat of the furnace by passing it to horizontal or vertical retorts,
similar to gas retorts, from which pipes must pass into the receiver or con-
denser, and to the apparatus preparing the metal. The acids in these
retorts may be obtained in the usual or other convenient way.
Figure 14 represents in vertical section a converting apparatus with two
retorts for containing the acids to be used in carrying my Invention into
effect. a is the body of the apparatus made of thick wrought or cast iron
plates, covered inside with segmental fire-clay bricks, or other bad conductor
of heat incapable of injuring the metal. The apparatus has two bottoms,
the upper one of which has a series of equidistant apertures, in which tuyeres
of either of the constructions represented in Figures 10, 11, 12, and 13 are
placed. The position of the tuyeres is indicated by lines. On the same
level as the tuyeres is a pipe or tube 6 for tapping the melted metal; con-
nected firmly to the body of the apparatus is a cast-iron hollow ring c,
opening into the interior of the apparatus by tuyeres and gas tubes. The
hollow bottom of the apparatus is joined by a metallic enamelled blast
pipe f, to which are connected two or more retorts d, e, as represented in
the Drawing. The top of the apparatus is covered by a hinged roof or
cover g, which can be raised and lowered by pulleys.

page_text: The action of the apparatus is as follows:-The melted crude iron or
re-melted pig iron is passed by a channel into the apparatus, the roof being
raise for that purpose. The requisite quantity having been introduced the
blast is admitted, together with the steam or vapour of acids from the retorts
d, e, or the steam or vapour of acids only. Should any acid remain in the
retorts d, e, from a former operation it should be used first. The retorts d, e,
are heated either by steam or by small furnaces. As soon as the pressure of
the steam or vapour of acid, separately or combined with a blast of air in the
space between the double bottom of the apparatus,exceeds that of the column
of metal and spring valves of the tuyeres, the said acid vapour, or combination
of acid vapour and blast enters the apparatus, and the converting process
commences; the process being carried to the desired extent either to produce
hard cast steel, soft cast steel, or malleable iron. Should the process be
carried inadvertently too far it will be necessary to re-carbonize the metal by
adding carbonized iron or other carbonizing agent thereto. prefer during
the process to admit pure coal gas, or other hydrocarbon gas rich in carbon,
or in some cases hydrogen through the side tubes. As the chemical com-
position of cast iron is not uniform, the converting operation is somewhat
changed to suit the iron being operated upon.
When the converting operation is carried on on a large scale I combine
several retorts or converting vessels, as represented in Figure 15, which
retorts or vessels may be fixed or moveable ou rails or tramways. In fixed
retorts or vessels the lower part may contain horizontal or vertical tuyeres
and tubes in the same or different planes. The bottoms of these converting
vessels are connected with the principal tube conveying the steam of acids,
or their mixture with air. The connection can be separated by valves for
repairing or other purpose.
Figure 16 represents a moveable converting vessel or apparatus. This
apparatus consists of a spherically formed vessel a, of ironwork covered with
fire-bricks, connected by means of axes 6 with large rail wheels, one of which
is marked c. The apparatus has an opening e at bottom for tapping the metal.
The cover fcarries a tubular shaft g, connected with the acid retorts. This
shaft is capable of rotating,and being raised or lowered. In using this apparatus
it is heated and the crude or re-melted iron introduced into it. The apparatus
is then conveyed under cover, and the steam or vapour of acids, or their
mixture with air, is admitted through the hollow shaft, which is lowered into
the melted metal, and the converting process begins; the blades h attached to
the said shaft stirring the metal. When the process is completed the metal
is poured into moulds or cast into ingots, the moulds being covered with

page_text: boiled oil and finely ground charcoal. As soon as the metal has solidified
it is removed and rolled or hammered in the usual way.
Having now described the nature of my Invention, and the manner in
which the same is to be performed, I wish it to be understood that I do not
limit myself to the precise details herein described and represented in the
Drawings, as the same may be varied without departing from the nature
of my Invention; but I claim as my Invention,-
Firstly, manufacturing cast iron in the blast furnace by introducing into
the said cast iron nitric acid, chloric acid, or other acid, which on being
heated liberates oxygen with or without admixture with air or gas, substan-
tially as herein-before described and illustrated in theaccompanying Drawings.
Secondly, treating cast iron so as to convert it into malleable iron or
steel, by introducing into the said cast iron nitric acid, chloric acid, or
other acid, which on being heated liberates oxygen, with or without
admixture with a blast of air or gas, or combined with potash, soda, lime,
or other base, substantially as herein-be ore described and illustrated in
the accompanying Drawings.
In witness whereof, I, the said Nicholas Korshunoff, have hereunto
set my hand and seal, this Twenty-first day of March, in the year
of our Lord One thousand eight hundred and sixty-six.
Witness,
RICHARD SKERRETT,
Clerk to George Shaw,
Birmingham.
NICHOLAS KORSHUNOFF. (L.S.)