Improvements in the Manufacture of Iron and Steel.
Year: 1886

page_text: Improvements in the Manufacture of Iron and Steel.
I JOHN HENRY JOHNSON of 47 Lincolns Inn Fields in the County of Middlesex
Gentleman do hereby declare the nature of this invention which has been com-
municated to me from abroad by La Société Anonyme de Commentry-Fourcham-
bault of Paris in the Republic of France to be as follows:-
This Invention relating to the manufacture of iron and steel consists in the
employment of a series of metallurgical operations or processes hereinafter described
whereby a product in the form of refined or purified cast iron or steel of given or
predetermined quality and the higher grades of these metals in particular is
enabled to be obtained from crude materials consisting of pig scrap or other iron
of any quality or degree of impurity.
In carrying out this invention crude or impure iron such as pig cast or scrap
iron or a mixture of these materials is melted preferably in a Siemens furnace
of circular form with a spherical roof such furnace being lined at all parts liable
to come in contact with the molten metal with a basic lining of dolomite, magnesi
or other basic material agglomerated with tar or other suitable substance. The
necessary temperature is obtained in this furnace by the combustion of gas pre-
ferably obtained from a Siemens or other gas generator or producer the air and gas
being heated preferably in Siemens regenerators of circular form and separate froin
and independent of the melting furnace.
Castina or limestone flux is charged along with the iron to be treated being
placed above the pigs when the fusion of the metal is complete the heat is
slackened and a certain proportion of oxide or peroxide of iron is introduced into
the bath in order to oxidise and eliminate the silicon, the said oxide being intro-
duced in the form of oxidised scrap or rich iron ore or hammer scale or the like
either alone or mixed with the lime the quantity employed being regulated according
to the chemical composition of the materials under treatment.

page_text: For example without limiting myself to these proportions which may be modified
according to circumstances, about two hundred weight of castina or lime flux and
about eighty pounds of peroxide of iron are introduced into the molten materials
for every one per cent of silicon contained in the latter but the quantity of lime-
stone flux and peroxide of iron may without disadvantage be in excess of that
actually required. It is of importance to employ a furnace provided with means
for regulating and maintaining the temperature according to the reactions or effects
to be produced and presenting facilities for watching the progress of the reactions
and taking samples.
In order to eliminate the sulphur the temperature of the furnace is raised and
spiegel iron containing from say about eight to ten per cent of manganese is intro-
duced. Reaction then takes place between the manganese and the sulphuret of
iron. A mixture composed of equal proportions of soda and lime or chloride of
sodium soda and lime or fluor spar and soda is then introduced care being taken
to raise the temperature of the furnace to the utmost thereby forming sulphurets
at a maximum of stability which pass into the slag and remain there.
The removal of the sulphur is thus effected by the combined action and at a
regulated temperature firstly of the manganese in the Spiegel iron which forms
a more stable sulphuret than sulpburet of iron and secondly of the lime and the
soda which form sulphurets inore stable than the sulphuret of manganese-The
addition of manganese in the form of Spiegel iron enables the acting ingredient
namely the manganese to be distributed owing to the density of this variety of
cast iron throughout the whole of the bath in such manner that the substances
which are required to react upon one another are intimately mixed and the
chemical effect that has to be produced by the heat being slight this intermediate
reaction is accomplished with facility and precision. For example without limiting
myself to these proportions about thirty pounds of spiegel iron containing about
ten per cent of manganese with about thirty pounds of one of the lime and soda
mixtures hereinbefore described is introduced into the bath for every thousandth
part of sulphur per ton of molten metal. When the slag has been skimmed off the
metal is run out into a ladle preferably made as deep as possible and lined at its
lower part with one of the aforesaid mixtures placed over the fireproof lining.
This ladle is then conveyed to a Siemens or other suitable finishing or refining
furnace and the molten metal is poured into this furnace through a channel opening
at one extremity into the hollow or recess of the ordinary charging door or
otherwise. As the molten metal is being transferred to the finishing furnace it is
further acted on by the reagents which ensure the complete elimination of the
sulphur. The finishing or refining furnace is lined at all parts coming into contact
with the molten metal with one of the basic linings herein before described in
connection with the melting furnace and oxides of iron in any of the forms
herein before described or lime or other base or both either separately or mixed
are introduced.
The carbon and the phosphorus are thereby oxidised, the oxide of carbon is
liberated in the form of gas and the phosphoric acid produced combines with the
bases forming a phosphate or phosphates which remain in the slag. On examina-
tion of samples taken and tested in the usual manner will show the quantity of
carbon and phosphorus remaining in the metal and consequently the amount
of purifying agents required in this operation. The refining is continued until
the metal is. converted into cast iron containing no phosphorus but sufficient
carbon to enable it to remain liquid. If it be desired to obtain cast iron the
contents of the furnace are run into the ingot ladles after introducing ferro
manganese containing a considerable quantity of manganese into the bath but
if steel is to be produced containing a given per centage of carbon some very pure
cast iron is to be introduced the proportion being readily calculated according
to the amount of carbon in the cast iron thus introduced and the contents of
the furnace are run into the ingot ladles after a final admixture of rich ferro
manganese.

page_text: By means of this process it is possible by taking the chemical analysis and the
indications afforded in working as guides to eliminate in' succession and with
precision all the substances or impurities which require removal in order to
convert impure crude cast or pig iron into steel or refined cast iron. This method
of manufacture constitutes an important step in advance of the ordinary treatment
in Siemens furnaces and also increases the output of the finishing or refining
furnace as the final refining takes place more rapidly. Moreover a great portion
of the expense of maintaining the plant is economised and the absorption by the
metal of the sulphur contained in the gases is obviated.

page_text: Improvements in the Manufacture of Iron and Steel.
I, JOHN HENRY JOHNSON of 47 Lincolns Inn Fields in the County of Middlesex
Gentleman do hereby declare the nature of this Invention which Invention has
been communicated to me from abroad by La Societe Anonymne de Commentry-
Fourchambault of Paris in the Republic of France and in what manner the same
is to be performed, to be particularly described and ascertained in and by the
following statement:-
This Invention relating to the manufacture of iron and steel consists in the
employment of a series of metallurgical operations or processes hereinafter described
whereby a product consisting of refined or purified cast iron or steel of given or
predetermined quality (the treatment being especially suited for obtaining the
higher grades of these metals) is enabled to be produced from crude materials
composed of pig scrap or other iron contaminated with variable proportions of
impurities. The raw material employed in carrying out this Invention may be
either cast iron alone or a mixture of cast iron and scrap iron or steel and may
contain in varying proportions silicon sulphur, carbon, and phosphorus.
The improved process forming the object of this invention comprises 4 distinct
operations having for their object the elimination of the silicon, the sulphur, the
carbon and the phosphorus in succession as hereinafter described.
In manufacturing cast iron and steel according to this invention from crude or
raw materials consisting of pig or scrap iron of apy composition the first operation
consists in melting the materials in a suitable furnace such as a Siemens furnace
of circular form and having a spherical top the said furnace being lined with
a suitable basic lining and heated by the combustion of gas from gas producers,
the air and gas being preferably heated in Siemens regenerators also circular and
independent of the melting furnace-When the materials are in a state of fusion
a suitable proportion of oxide of iron such as rich iron ore or scale alone or mixed
with lime is introduced for the purpose of eliminating the silicou.
The second operation consists in elevating the temperature of the furnace and
eliminating the sulphur by introducing Spiegel Iron containing from 8 to 10 per cent
of Manga ese then adding a mixture of equal parts of Soda and Lime or Chloride
of Sodium-soda and lime or fluor spar and soda the temperature of the furnace
being at the same time raised to the utmost.
The third operation consists in transferring the molten metal to a finishing or
refining furnace or apparatus preferably a Siemens furnace provided with a suitable
basic lining and at the same time ensuring the complete removal of the Sulphur
by employing deep ladles lined over the usual refractory liuing with one of the
lime and soda mixtures specified and described in the second operation. From
these ladies the metal is delivered into a channel leading to the hollow or recess of
the charging door of the finishing furnace.
The fourth operation consists in effecting the separation or removal of the carbon
and of the phosphorus in the aforesaid finishing furnace by the addition of oxide

page_text: of iron or lime or other base either alone or mixed then removing. the cast iron
into ingots of iron or steel the latter being obtained by adding cast iron in propor-
tions regulated according to the percentage of carbon remaining in the metal in the
furnace and the amount of carbon present in the cast iron so added.
For melting the materials in carrying out the first operation a Siemens furnace
of circular form and with a spherical roof is employed such furnace being lined at
all parts liable to come in contact with the molten metal with a basic lining of
dolomite, magnesia, or other basic material agglomerated with tar or other suitable
material.
The necessary temperature is obtained in this furnace by the combustion of gas
obtained from a Siemens or other like Gas generator or producer the air and gas
being heated preferably in Siemens regenerators of circular form and separate
from and independent of the melting furnace.
A limestone flux is introduced into the furnace along with the charge being
placed above the pigs or lumps of metal-When the fusion of the metal is com-
plete the heat is slackened and a certain proportion of oxide or peroxide of iron is
introduced into the bath in the form of oxidized scrap or rich iron ore, or hammer
scale or the like either alone or mixed with lime the quantity employed being
regulated according to the chemical composition of the materials under treatment
this oxide of iron has the effect of oxidizing the whole of the silicon and as
the silicon thus produced is in the presence of the residue of highly basic slag
resulting from the preceding operation and of the lime introduced with the charge
a highly basic silicate is formed. The whole of the silicon is thus removed and
constitutes a slag with multiple bases containing as small a proportion of silica as
may be desired say from about ten to fifteen per cent of Silica, this being the
proportion which appears most desirable in practice but this quantity may be still
further reduced if desired.
For example without limiting the invention to these proportions which may be
modified according to circumstances about two hundred weight (100 K) of the lime
flux and about eighty pounds (40 K) of oxide or per oxide of iron in any of the
above mentioned forms are introduced into the molten materials for every one per
cent of silicon contained in the latter or in other words for every twenty pounds
(10 K) of silicon contained in a ton of metal to be treated corresponding to about
forty five pounds (21.6 K) of silica.
There is no advantage in increasing the weight of peroxide of iron or flux as
the excess of flux floats on the surface of the bath, and can be used for the next
charge and an excess of peroxide insures the oxidation of the whole of the silicon
any oxygen not required for this purpose being taken up either by the phosphorus
or by the carbon,
This first operation thus conducted in the apparatus described enables the whole
of the silicon to be removed with certainty notwithstanding the varying propor-
tions in which this substance is present in cast metal as the quantity of limestone
flux and peroxide of iron may without disadvantage be in excess of that actually
required. It is of importance to employ a furnace provided with means for
regulating and maintaining the temperature accurately according to the reactions
or effects to be produced it being necessary to maintain the bath at a relatively
low temperature at the time when the oxides of iron are introduced in order to
avoid a too rapid oxidation of the carbon moreover furnaces of the class herein
before referred to present facilities for watching the progress of the reactions and
taking samples which cannot be done when for example a cupola furnace is
employed for the fusion and the partial purification as it is not possible in this case
to watch the raw materials in their descent or to observe how the reactions are
progressing at all times and at all parts or to modify them in such a manner as to
obtain a given result with any degree of certainty.
The elimination of the sulphur forms the object of the second operation. For
this purpose the temperature of the furnace is raised and spiegel iron containing
from about eight to ten per cent of manganese is introduced. Reaction then takes

page_text: place between the manganese and the sulphuret of iron. A mixture composed of
equal proportions of soda and lime; or chloride of sodium, soda and lime, or fluor
spar and soda is then introduced care being taken to raise the temperature of the
furnace to the utmost so that the chemical action of the heat may produce its full
effect and results in the formation of sulphuretted compounds requiring the
maximum of caloric and presenting a maximum of stability that is to say
sulphurets of sodium or of calcium whose stability may be represented by 4 that
of sulphuret of manganese being 2 and that of sulphuret of iron 1 only. These
sulphurets at a maximum of stability pass into the slag and remain there.
This part of the Invention consists essentially in effecting the removal of the 1
sulphur by means of a rise in temperature acting in combination firstly with the
manganese in the spiegel iron which forms a more stable sulphuret than sulphuret
of iron and secondly with the lime and the soda which subsequently form sulphurets
more stable than the sulphuret of manganese The addition of manganese in the
form of spiegel iron enables the acting ingredient namely the manganese to be
distributed owing to the density of this variety of cast iron throughout the whole
of the bath or mass of molten metal in such manner that the substances which are
required to react upon one another become ultimately mixed, and, the chemical
effect that has to be produced by the heat being slight, this intermediate reaction is
accomplished with facility and precision For example without limiting myself to
these proportions about thirty pounds (15 K) of spiegel iron containing about ten
per cent of manganese with bout thirty pounds (15 K) of one of the lime and
soda mixtures herein before described is introducod into the molten metal in dealing
with materials containing 0.1 per cent of sulphur materials that is to say containing
about two pounds (1 K) of sulphur per ton the quantity of the aforesaid purifying
agents being increased in direct proportion to the quantity of sulphur to be
eliminated.
The transference of the metal to the finishing or refining furnace and the comple-
tion of the elimination of the sulphur forms the object of the third operation When
the slag has been skimmed off the metal is run out through an ordinary tapping
hole into a ladle or ladles preferably made as deep as possible and lined at the
lower part with one of the aforesaid lime and soda mixtures placed over the usual
fire proof lining This ladle is then conveyed to one of the Siemens or other suitable
finishing or refining furnaces, the molten metal being poured into this furnace
through a channel communicating at one extremity with the hollow or recess of
the ordinary charging opening-As the molten metal is being transferred from the
circular melting furnace to the finishing furnace it is further acted on by the
reagents in the ladle which ensure the complete elimination of the sulphur.
The fourth operation has for its object the removal of the carbon and phosphorus
For this purpose the molten metal is run into a Siemens finishing furnace of the
ordinary type of construction covered or lined at all parts coming into contact with
the molten metal that is to say on the sole and at the sides with one of the basic
linings bereinbefore described in connection with the melting furnace and an oxide
or oxides of iron in any of the forms herein before described and a lime or other
base either separately or mixed are introduced into the bath The carbon and the
phosphorus are thereby oxidised the oxide of carbon is liberated in the form of gas
and the phosphoric acid produced combines with the bases forming a phosphate or
phosphates which remain in the slag and are incapable of being further decomposed
The weight of oxide of iron and bases to be used depends on the condition of the
materials After a roughly estimated quantity has been introduced and taken effect
an examination of samples taken and tested successively in the usual manner will
show the quantity of carbon and phosphorus remaining in the metal and conse-
quently the amount of purifying agents required to complete the operation. The
refining is continued until the metal is converted into cast iron containing no
phosphorus and only sufficient carbon to enable it to remain liquid If it be desired
to obtain cast iron the contents of the furnace are run into the ingot ladles after
introducing ferro manganese containing a considerable quantity of manganese into

page_text: the bulk but if steel is to be produced containing a given per centage of carbon
some very pure cast iron to be introduced the proportion being readily calculated
according to the amount of carbon in the cast iron thus introduced and in the
inetal under treatment and the contents of the furnace are run into the ingot ladles
after a final admixture of rich ferro-manganese.
By means of this process it is possible by taking the results of the chemical
analysis and the indications afforded in working as guides to eliminate in succession
and with precision all the substances or impurities which require removal in order
to convert crude cast or pig or other impure iron into steel or refined cast iron-
This method of manufacture constitutes an important step in advance of the
ordinary treatment in Siemens furnaces and also increases the output of the
finishing or refining furnace as the final refining takes place more rapidly than
heretofore Moreover a great portion of the expence of maintaining the plant is
economised and the absorption by the metal of the sulphur contained in the gases
is obviated.
In conclusion it may be observed the results hereinbefore set forth cannot be
obtained with the agents specified by treating the metal in one and the same
furnace even if such furnace were lined with a basic lining as the chemical reactions
would neutralise one another the phosphates and sulphates resulting from the
oxidation of the phosphorus and sulphur by the oxides of iron for example would
be decomposed by the silicates in such a manner that the phosphorus and the
sulphur would return to or re-combine with the metal and in like manner even
assuming the practically impossible condition of the absence of silicates the
phosphates would be decomposed by the sulphates.
Having now particularly described and ascertained the nature of the said
Invention and in what manner the same is to be performed I declare that
what I claim is
Obtaining iron and steel of any desired quality or degree of purity from materials
contaminated with silicon, sulphur, carbon and phosphorous by firstly eliminating
the silicon by fusing the materials in a gas furnace provided with a basic lining as
berein before set forth and introducing oxide or peroxide of iron into the molten
metal, secondly, eliminating the sulphur by elevating the temperature of the
materials and introducing spiegel iron containing from about to 10 per cent of
manganese followed by a mixture composed of soda and lime or soda and fluor
spar in about equal proportions, thirdly; transferring the materials to a basic lined
refining furnace in special ladles having a lining composed of one of the aforesaid
soda mixtures, and, fourthly; effecting the separation or removal of the carbon and
phosphorus in the said finishing or refining furnace by introducing oxide of iron
and lime either separately or mixed, cast iron being subsequently introduced when
making steel, the quantity of cast iron so introduced being regulated according to
the percentage of carbon therein contained and that remaining in the metal under
treatment, all substantially as herein before described.