IMPROVEMENTS IN THE MANUFACTURE OF IRON AND STEEL
Year: 1877

page_text: LETTERS PATENT to Alfred Longsdon, of Queen Victoria Street, in the City of
London, Engineer, for the Invention of "IMPROVEMENTS IN THE MANUFACTURE
OF IRON AND STEEL." A communication from abroad by Alfred Krupp, of
Essen, in the Empire of Germany, Cast Steel Manufacturer.
"
PROVISIONAL SPECIFICATION left by the said Alfred Longsdon at the Office
of the Commissioners of Patents on the 1st May 1877.
ALFRED LONGSDON, of Queen Victoria Street, in the City of London, Engineer.
IMPROVEMENTS IN THE MANUFACTURE OF IRON AND STEEL." (A communication
from abroad by Alfred Krupp, of Essen, in the Empire of Germany, Cast Steel
Manufacturer).
According to this Invention, pig iron as it is produced in the blast furnaces, which
as is well known often contains impurities which it is necessary to eliminate, is treated
while in a fluid state, by bringing it into contact with basic iron oxides alone, or in
combination with manganese oxides, and is subjected to what may be termed a
decomposition. In other words, the phosphorous or other impurity, such as silicon,
is caused to combine with the oxygen of the iron oxides, or with the manganese
oxides, and at the same time metallic iron is eliminated from the iron oxides. When
the pig iron contains manganese it acts in such a way that it takes the place of
metallic iron which is extracted from the protoxide of iron or sesquioxide of iron,
because the manganese has much greater affinity for the oxygen. Again, the man-
ganese acts upon sulphur, combining with it, and forms sulphide of manganese.
Also the action of the manganese when combined with the silicic acid, the phosphoric
acid, and the sulphur, is a very favorable one, because it renders at the working
temperature the slag very fluid, and facilitates therewith the reactions of the various
substances. Besides, manganese acts for the preservation of carbon in the pig iron
if the pig iron is brought into contact with basic oxides of iron or manganese in the
manner before described, because the silicate of protoxide of manganese which is
formed is not able, like the silicate of protoxide of iron, to dissolve mechanically

page_text: the magnetic oxide of iron (Fe,, O₁), that is to say, the chemical substance which
attacks the carbon; therefore if silicate of protoxide of manganese is in the slag,
or if it is formed out of the pig iron (employed), then free magnetic oxide of iron
(Fe, O) cannot be present in the slag in such proportion as it would be if the slag
contains no protoxide of manganese, therefore the attack upon the carbon through
the basic oxides of iron will be the more retarded the more manganese is
contained in the pig iron, and from which it passes into slag, and there will be
gained more time for the process and the action upon the other impurities than if
there is employed only a pig iron without manganese, and a slag without manganese.
At the same time the combination of the protoxide of manganese with silicic
acid and phosphoric acid is a far more solid and constant one than the silicate
and phosphate of protoxide of iron, therefore the silicate and phosphate of
manganese are more easily formed and in a larger per-centage proportion than those
of protoxide of iron. For all these reasons a pig iron containing manganese is to be
preferred to a pig iron without manganese. Copper remains unaltered in the metal.
In theory all these reactions may be said to be instantaneous, and in the cases where
the pig iron does not contain too large a per-centage of impurities, the carbon
remains unattached so long as there are tangible traces of the above-named substances,
viz., phosphorous, silicon, sulphur, and manganese.
The above-described reactions, especially so far as concerns the phosphorous, are
performed very completely if there is a certain amount of manganese in the pig iron
or in the ore which is added, and nearly all the phosphorous is eliminated, provided
a substantial per-centage of manganese is present in the pig iron. If therefore a pig
iron in the fluid state and at the requisite temperature is brought into contact with
iron oxides or with manganese oxides, whether in the form of iron ores, hammer
scales, or manganese ores, or any oxides produced by any manufacturing or
chemical artificial means, then will result a metal which contains all the carbon
of the primitive pig iron, while it has exchanged nearly all the foreign compounds
contained in the primitive pig for parts of iron given up in exchange, supposing that
the chemical action of the iron oxides or manganese oxides has been intercepted at
the right moment, and the carbon having been completely retained in the resulting
metal, the metal is still completely fluid.
The mode of working this Invention is as follows:-A fluid pig iron is run, either
direct from the blast furnace or from a secondary melting furnace, into a hearth,
which is lined with the before-named basic oxides of iron or manganese, separately
or both combined, and as soon as the pig iron has lost its impurities, viz., phosphorous,
manganese, silicon, and sulphur, it is tapped, and the fluid metal is either run direct
or transported in a ladle to a furnace, the hearth of which is lined with acid material,
such as quartzyte-sand, or argillaceous matters, for making fluid steel or fluid iron,
or into a puddling furnace for making puddled steel or puddled iron.
If
The slags which contain the before-named impurities of the pig iron are of a far
lighter specific gravity than the fluid iron, which still contains all its carbon.
therefore the cleaned metal is run by means of channels direct into the acid hearth
the slags containing the impurities may be easily taken off during the running of the
metal to the furnace; or if the cleaned metal is tapped into a ladle, it may
very easily be separated from the slags containing the impurities by running the
metal out through the bottom of the ladle, in a manner similar to that used in the
Bessemer process, and well known, and stopping the flow from the ladle directly the
whole of the metal has run through from the ladle.
The novelty of this Invention consists thererefore in tapping the metal when
cleaned by the process above described, and running it while in the fluid state out
from the basic hearth, where it has been separated from its impurities. The cleaned
iron is thereby separated from its slag, and according to the primitive composition of
the pig iron it can be worked into steel of any required quality, or into soft iron of
any required quality, whether cast soft iron, or puddled iron.
The results from tapping off the cleaned pig iron while in the fluid state are very

page_text: important, as with fluid substances large quantities may be manipulated. The metal
when thus cleaned from its impurities, but containing its carbon, is run into an
ordinary Siemens' steel melting furnace, and there oxidised in this acid hearth by
any means adapted thereto, and while the metal remains fluid, the heat of the metal
increasing at the same time. These means for oxidising the carbon may consist in
treating the metal with oxides of iron, either in the shapo of hammer scales or iron
ores, or decarbonizing the metal by air blown into or through it when the carbon
has been eliminated entirely, or to the required extent; the manner of proceeding for
producing finished metal is the same as now employed in the Siemens-Martin
process, for making, by appropriate additions, steel and fluid iron of every required
quality, also the cleaned metal may be worked in any ordinary puddling furnace
into steel and iron.
The cleaned metal which now contains, besides carbon, hardly any foreign
substances, may also be used in the Bessemer process by smelting it and adding the
necessary quantity of highly silicised or manganised pig iron, or a mixture of both,
or it may be remelted in furnaces with sufficient blast, and adding thereto an
appropriate mixture of ores or artificial products which contain those substances,
viz., manganese or silicon, or both.
In order to carry out this Invention, the pig iron is run direct from the blast
furnace, or remolten pig iron from the cupola or other suitable melting furnaces,
into a movable furnace by preference, such furnace revolving or turning horizontally
or on an inclined plane, or into a furnace with a fixed hearth, the bottom and walls
of which are lined or fettled with iron oxides or manganese oxides, containing as
small a quantity of silicic acid as possible. When the furnace has been raised to a
temperature in which iron sesquioxide mixed with protoxide of iron and protoxide
of manganese commences to be fluid, then a certain quantity of sesquioxide or
protoxide of iron and basic manganese oxides (both as free from silicic acid as
possible) is charged upon the hearth; when these materials are at a cherry-red
heat, the above-named pig iron is run or poured into the furnace upon the basic
hearth. The chemical reaction very quickly begins, and for a quantity of iron, say,
of 5 tons, it requires from three to ten minutes, according to the chemical composition
of the pig iron, also according to the temperature and to the chemical composition of
the added materials.
The point where the impurities above referred to are separated is very
easily and exactly to be determined, because the above-named impurities are
separated before the carbon is affected. Directly therefore when the right
moment has come, and the impurities are eliminated, then the carbon will be
attacked by the oxygen of the iron oxides or manganese oxides, and there will be
formed gaseous oxides of carbon, which, passing through the slag swimming upon the
metal, will, generate bubbles, and as soon therefore as the metal commences to
generate these bubbles, it must be tapped off and separated from the slag which con-
tains the impurities. The metal is then to be run into or otherwise transported in
the fluid state into a steel-melting furnace, puddling furnace, or remelting furnace,
for the Bessemer process or the fluid metal may be run into moulds, or made into
pigs, and be treated afterwards by any of the ordinary processes.
"
Since the operation in the basic hearth requires only a very short time, and since
the hearth if it has given to it (before pouring the pig into it) the proper
addition of iron oxides or manganese oxides is not affected in any high degree, there
tons every
is not need of any great repair, and there can be made a charge of, say,
hour (more or less), and the thus cleaned pig iron may be immediately worked to
its intended purpose in the acid hearth, differing essentially from the basic hearth for
making fluid steel or fluid iron; or it may be treated in one or several puddling
furnaces for making puddled steel or puddled iron.
The fluid product of the acid hearth, whether it is steel or fluid soft iron, can
as in the present melting works for steel or fluid soft iron, be cast by appropriate
desired
apparatus into moulds, and the ingots may be worked into any
purpose,

page_text: according to the quality of the primitive pig iron, or the blooms made in the
puddling furnace may be worked up, according to the known manner, into finished
products.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Alfred Longsdon in the Great Seal Patent Office on the 1st November
1877.
ALFRED LONGSDON, of Queen Victoria Street, in the City of London, Engineer.
"IMPROVEMENTS IN THE MANUFACTURE OF IRON AND STEEL." (A communication
from abroad by Alfred Krupp, of Essen, in the Empire of Germany, Cast Steel
Manufacturer.)
According to this Invention pig iron as it is produced in the blast furnaces (which
as is well known often contains impurities which it is necessary to eliminate)
is treated while in the fluid state by bringing it into contact with basic iron oxides
alone or in combination with manganese oxides, and is subjected to what may be
termed a decomposition, so as to cleanse it from impurities. In other words, the
impurities, such as phosphorus or silicon, are caused to combine with the oxygen of
iron oxides or with the manganese oxides, and at the same time metallic iron is
eliminated from the iron oxides. When the pig iron contains manganese it acts in
such a way that it takes the place of metallic iron which is extracted from the
protoxide of iron or sesquioxide of iron, because the manganese has much greater
affinity for the oxygen. Again, the manganese acts upon sulphur, combining with it,
and forms sulphide of manganese. Also, the action of the manganese when com-
bined with the silicic acid, the phosphoric acid, and the sulphur, is a very favorable
one, because it renders at the working temperature the elag very fluid, and facilitates
therewith the reactions of the various substances. Besides, manganese acts for the
preservation of carbon in the pig iron, if the pig iron is brought into contact with
basic oxides of iron or manganese in the manner before described, because the
silicate of protoxide of manganese which is formed is not able, like the silicate of
protoxide of iron, to dissolve mechanically the magnetic oxide of iron (Fe, 0);
that is to say, the chemical substance which attacks the carbon. Therefore, if
silicate of protoxide of manganese is in the slag, or if it is formed out of the pig
iron (employed), then free magnetic oxide of iron (Fe, O₁) cannot be present in the
alag in such proportions as it would be if the slag contains no protoxide of man-
ganese, therefore the attack upon the carbon through the basic oxides of iron will
be the more retarded the more manganese is contained in the pig iron, and from
which it passes into slag, and there will be gained more time for the process and the
action upon the other impurities than if there is employed only a pig iron without
manganese and a slag without manganese. At the same time the combination of
the protoxide of manganese with silicic acid and phosphoric acid is a far more solid
and constant one than the silicate and phosphate of protoxide of iron, therefore the
silicate and phosphate of manganese are more easily formed, and in a larger per-
centage proportion than those of protoxide of iron. For all these reasons a pig
iron containing manganese is to be preferred to a pig iron without manganese.
Copper remains unaltered in the metal. In theory all these reactions may be said
to be instantaneous, and in the cases where the pig iron does not contain too large
a per-centage of impurities, the carbon remains unattacked so long as there are
tangible traces of the above-named substances, vizt., phosphorus, silicon, sulphur,
and manganese.
The above-described reactions, especially so far as concerns the phosphorus, are
performed very completely if there is a certain amount of manganese in the pig
iron or in the ore which is added, and nearly all the phosphorus is eliminated, pro-
vided a substantial per-centage of manganese is present in the pig iron. I have

page_text: found that if a pig iron in the fluid state and at the requisite temperature is brought
into contact with iron oxides or with manganese oxides, whether in the form of
iron ores, hammer scales, or manganese ores, or any oxides produced by any manu-
facturing or chemical artificial means, then will result a metal which contains all
the carbon of the primitive pig iron, while it has exchanged nearly all the foreign
compounds contained in the primitive pig for parts of iron given up in exchange,
provided that the chemical action of the iron oxides or manganese oxides has been
intercepted at the right moment, and the carbon having been retained in the resulting
metal, the metal is still completely fluid.
The mode of working this Invention is as follows: A fluid pig iron is run either
direct from the blast furnace or from a secondary melting furnace into a hearth
which is lined with the before-named basic oxides of iron or manganese, separately,
or both combined, and as soon as the pig iron has lost its impurities, viz., phos-
phorus, manganese, silicon, and sulphur, it is tapped, and the fluid metal is either
run direct or transported in a ladle into a furnace, the hearth of which is lined
with an acid material, such as quartzite sand, or argillaceous matters for making
fluid steel or fluid iron, or into a puddling furnace for making puddled steel or
puddled iron.
The slags which contain the before-named impurities of the pig iron are of a far
lighter specific gravity than the fluid iron, which still contains all its carbon. If,
therefore, the cleaned metal is run by means of channels direct into the acid hearth,
the slags containing the impurities may be easily taken off during the running of
the metal to the furnace. Or if the cleaned metal is tapped into a ladle, it may
very easily be separated from the slags containing the impurities by running the
metal out through the bottom of the ladle in a manner similar to that used in the
Bessemer process, and well known, and stopping the flow from the ladle directly the
whole of the metal has run through from the ladle.
The novelty of this Invention consists therefore in cleaning the metal from impu-
rities by the process above described, and then tapping and running it while in the
fluid state out from the basic hearth, where it has been separated from its impurities
into another hearth or furnace, where it is further treated in any manner that may
be desired, having regard to the purpose. The cleaned iron is thereby separated
from its slag, and according to the primitive composition of the pig iron, it can be
worked into steel of any required quality, or into soft iron of any required quality,
whether cast soft iron or puddled iron.
The results from tapping off of the cleaned pig iron while in the fluid state are
very important, as with fluid substances large quantities may be manipulated. The
metal when thus cleaned from its impurities, but containing its carbon, is run into
an ordinary Siemens' steel melting furnace and there oxidised in this acid hearth
by any means adapted thereto, and while the metal remains fluid, the heat of the
metal increasing at same time. These means for oxidising the carbon may consist
in treating the metal with oxides of iron, either in the shape of hammer scales, or
iron ores, or decarbonising the metal by air blown into or through it. When the
carbon has been eliminated entirely or to the required extent, the manner of pro-
ceeding for producing finished metal is the same as now employed in the Siemens-
Martin process for making by appropriate additions steel and fluid iron of every
required quality, also the cleaned metal may be worked in any ordinary puddling
furnace into steel and iron.
The cleaned metal which now contains besides carbon hardly any foreign
substances may also be used in the Bessemer process, by smelting it and adding the
necessary quantity of highly silicised or manganised pig iron, or a mixture of both,
or it may be remelted in furnaces with sufficient blast, and adding thereto an
appropriate mixture of ores or artificial products which contain those substances,
vizt., manganese, or silicon, or both.
In order to carry out this Invention, the pig iron is run direct from the blast
furnace, or remolten pig iron from the cupola or other suitable melting furnaces, into
a movable furnace by preference, such furnace revolving or turning horizontally, or

page_text: on an inclined plane, or into a furnace with a fixed hearth, the bottom and walls of
which are lined or fettled with iron oxides or manganese oxides, containing as small
a quantity of silicic acid as possible. When the furnace has been raised to a tem-
perature in which iron sesquioxide mixed with protoxide of iron and protoxide of
manganese commences to be fluid, then a certain quantity of sesquioxide or protoxide
of iron and basic manganese oxides (both as free from silicic acid as possible) is
charged upon the hearth. When these materials are at a cherry-red heat, the
above-named pig iron is run or poured into the furnace upon the basic hearth. The
chemical reaction very quickly begins, and for a quantity of iron, say, of five tons, it
requires from three to ten minutes, according to the chemical composition of the pig
iron, also according to the temperature and to the chemical composition of the
added materials.
The point where the impurities above referred to are separated is very easily and
exactly to be determined, because the above-named impurities are separated before
the carbon is affected. Directly therefore when the right moment has come and the
impurities are eliminated, then the carbon will be attacked by the oxygen of the
iron oxides or manganese oxides, and there will be formed gaseous oxides of carbon,
which, passing through the slag floating upon the metal, will generate bubbles, and
as soon therefore as the metal commences to generate these bubbles, it must be
tapped off and separated from the slag which contains the impurities. The metal
is then to be run into or otherwise transported in the fluid state into a steel
melting furnace, puddling furnace, or re-melting furnace for the Bessemer process, or
the fluid metal may be run into moulds or made into pigs, and be treated afterwards
by any of the ordinary processes.
Since the operation in the basic hearth requires only a very short time, and since
the hearth, if it has given to it (before pouring the pig into it) the proper addition
of iron oxides or manganese oxides, is not affected in any higher degree, there is not
need of any great repair, and there can be made a charge of, say, of five tons every
hour (more or less); and the thus cleaned pig iron may be immediately worked to its
intended purpose in the acid hearth, differing essentially from the basic hearth, for
making fluid steel or fluid iron. Or it may be treated in one or several puddling
furnaces for making puddled steel or puddled iron.
The fluid product of the acid hearth, whether it is steel or fluid soft iron, can as
in the present melting works for steel or fluid soft iron be cast by appropriate
apparatus into moulds, and the ingots may be worked into any desired purpose,
according to the quality of the primitive pig iron, or the blooms made in the
puddling furnace may be worked up according to the known manner into finished
products.
"
"
Having now described the nature of the said Invention and in what manner the
same is to be performed, I declare that I wish it to be understood by the word
second," that a second or another furnace is used having either an acid hearth like
Siemens" or with a basic hearth like any puddling furnace, or even similar to the
cleaning furnace itself. Under all circumstances a second furnace is employed, that
is, two furnaces until the finished product is obtained. Again, the fluid iron might
be cleaned as it runs direct from the blast furnace, in order to obtain by puddling it
after it has been cleaned a superior quality, whether poured into the puddling
furnaces while liquid, or sent as cleaned pigs to puddling works at a distance,
and I claim as the aforesaid improvements in the manufacture of iron and steel,―
First. The cleaning of fluid pig iron when run from a blast furnace or a secondary
melting furnace in a basic hearth by means of basic iron oxides or manganese
oxides in such manner as to separate from it its impurities (such as silicon, phos-
phorus, and sulphur), the said fluid pig iron being tapped from this basic hearth
before it has lost the carbon, thus preserving its fluid state so as to enable it to be
worked in a second furnace and produce the required finished product, all substan-
tially as herein set forth.
Second. The manufacture of iron and steel as herein described by treating iron
in the molten state (either taken directly from the blast furnace or re-melted) in a

page_text: suitable furnace lined with basic materials, such furnace being stationary, or
revolving, or oscillating, or having other motion communicated to it, and thus
eliminating from the molten metal the impurities therein contained, and then
running the metal thus cleaned and while in a fluid state and separating it from its
slag into an acid hearth (such as the Siemens' reverberatory furnace or other suitable
furnace or converter) and there decarbonizing the metal or otherwise treating it so
as to produce the desired quality of iron or steel, substantially as herein-before
described and set forth.
In witness whereof, I, the said Alfred Longsdon, have hereunto set my hand
and seal, this First day of November, in the year of our Lord One thousand
eight hundred and seventy-seven.
ALFRED LONGSDON. (L.S.)