An Improved Process for Effecting the Preliminary Refining of Pig-iron.
Year: 1898

page_text: Date of Application, 11th Oct., 1898
Complete Specification Left, 1st July, 1899—Accepted, 5th Aug., 1999
PROVISIONAL SPECIFICATION.
An Improved Process for Effecting the Preliminary Refining of
Pig-iron.
We, LEOPOLD PSZCZOLKA, of Vienna II, in the Empire of Austria-Hungary,
Director of Foundry, and REINER MARIA DAELEN, of Dusseldorf, in the Empire
of Germany, Civil Engineer, do hereby declare the nature of this invention
to be as follows:-
In methods heretofore adopted for effecting the preliminary refining of pig
iron in a Bessemer converter, in connection with the operation of final refining
in a second converter or in a hearth smelting-furnace (Siemens-Martin furnace)
the operator as far as the generation of the amount of heat is concerned which
is requisite for preserving the bath in a fluid condition-is solely dependent upon
the contents of foreign matter, silicium, manganese, carbon and so forth, which
contents must be larger in proportion as the refining operation is to be carried
on further, seeing that, as the foreign matter is being eliminated, the fusing
point of the iron is raised.
The simplest and most economical process consists in withdrawing the pig
iron directly in its liquid state from the blast-furnace, as however the working
process very frequently varies, the percentage of foreign matter contained in the
pig iron, especially that of silicium, forming the most efficient heating body,
naturally also changes. The working of the blast furnace, moreover, is the
least expensive if serving for the production of white pig iron containing only a
quantity of silicium varying between 03 and 08 per cent. or thereabouts, an
amount which is insufficient for carrying out the ordinary Bessemer process
with cold compressed air. Thus in the case of refining in the acid-converter, a
grey pig iron containing from two to three per cent. of silicium, and in the case
of refining in the basic converter a grey pig iron containing from two to three
per cent. of phosphorous, is produced.
In the former product the noxious body, namely sulphur is retained from the
iron by the basic slag in the blast furnace, whereas to the latter product a quantity
of from 15 to two per cent. of manganese is added for the purpose of eliminating
the sulphur.
All these operations tend to increase the work and it is desirable, to dispense
with the necessity of such operations. This problem may be considered as solved,
as soon as the preliminary refining of a pig iron of 03 per cent. of silicium can
be effected in a converter in a manner yielding a sufficiently high temperature,
so that the iron bath, after the combustion of the greater part of silicium and
of the carbon up to 10 or 15 per cent., is still so fluid, that, when having been
passed over into another converter or into a hearth smelting-furnace, it can,

page_text: within a sufficiently short time, be ready-refined to iron or to steel in fusion, so
that twice as many charges may be carried out per day in a hearth furnace, than
in the case of inserting pig iron, that, moreover, the temperature admits of being
so regulated, as not to rise too high, in order not to have too destructive an
effect upon the refractory lining, if, owing to the fluctuations in the working of
the blast furnace, the pig iron should contain more than 1 per cent. of silicium,
and that after the operation of preliminary refining being finished or during an
interruption in the said operation, the sulphur is eliminated.
For this purpose a converter for preliminary refining is arranged as near as
possible to the blast furnace, the liquid pig iron being passed from the latter into
the converter by means of a gutter or conduit, if possible without the use of an
intermediate pan, and being refined by blowing hot compressed air into and over
the product. As this hot compressed air is most inexpensively supplied by the
furnace, blasts and by the air heating devices, it is drawn from the general
conduit, and, as in this latter the tension of pressure is in most cases con-
siderably lower than is required in case of a Bessemer converter with feed
through the bottom, the converter for effecting the preliminary refining receives
lateral air-feed nozzles located below or above the top surface of the bath.
The temperature of the compressed air of the blast furnace, in most cases varies
between 500 and 1000 degrees Centigrade, but, as in case of the pig iron
containing too high a percentage of silicium the temperature in the converter
for preliminary refining is to be lowered, therefore, in addition to the conduit
for conveying hot air from the heaters, a second conduit passing direct from
the blast to the converter, is arranged, so that by way of mixing hot air with
cold air by the proper regulation of dampers arranged for this purpose, any
desired temperature up to 1000 degrees Centigrade can be produced prior to the
entering into the converter, whereby the working of the process can be regulated.
If nevertheless the temperature in the converter for effecting the preliminary
refining should become too high, it is as a matter of experience, not suitable to
cool the air below 150 degrees because then an incomplete combustion would
take place and too large a quantity of free oxygen would be thus lost, therefore,
in this case an oxydizing body must be added, which in yielding oxygen will
disengage a smaller amount of heat than the air, and this oxydizing body consists
of a metallic oxide, for instance iron oxide, such as is present in iron ore or in
so-called hammerslag or scales of iron; such metallic oxide yields about two
thirds of free heat less than the air and is introduced into the converter in
a pulverized form together with the blast air.
For effecting the desulphuration it is preferable, that after the termination
of the preliminary refining or sometimes also during an interruption of
the preliminary refining operation, the slag be discharged from the converter,
in which the preliminary refining is effected, that subsequently a quantity of
manganese or of iron containing manganese, in either case corresponding to the
percentage of silicium, is added, which rapidly combines with the sulphur,
because of the iron bath being very hot and rises to the surface in the form of
sulphate of manganese, so that it admits of being discharged like the slag, the iron
thus having undergone the preliminary refining is then, according to its per-
centage of phosphorous, ready for further treatment either in the basic Bessemer
converter or in the hearth-furnace.
For carrying the above described process into practice the pig iron may either
be passed from the blast furnace direct to a fixed converter for preliminary
refining and thence into the hearth-furnace or basic converter, or into one or
more intermediate pans, or a portable converter may be employed, which latter
device commends itself in case of several blast furnaces being used, seeing that
such portable converter admits of being transported from one furnace to the
other, as well as to the hearth-furnace or to the converter and that the iron is thus
refined with the least possible amount of heat being lost. To insert, however,
an intermediate pan is likewise here admissible, if the number of blast furnaces

page_text: is so great that the transport of the converter to the steel works would occupy too
much time for effecting the required number of charges per day.
Dated this 10th day of October 1898.
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C.,
Agents for the Applicants.
COMPLETE SPECIFICATION.
An Improved Process for Effecting the Preliminary Refining of
Pig-iron.
We, LEOPOLD PSZCZOLKA, of Vienna II, in the Empire of Austria-Hungary,
Director of Foundry, and REINER MARIA DAELEN, of Dusseldorf, in the Empire
of Germany, Civil Engineer, do hereby declare the nature of this invention
and in what manner the same is to be performed, to be particularly described and
ascertained in and by the following statement:-
In methods heretofore adopted for effecting the preliminary refining of pig
iron in a Bessemer converter, in connection with the operation of final refining
in a second converter or in a hearth smelting-furnace (Siemens Martin furnace)
the operator-as far as the generation of the amount of heat is concerned which
is requisite for preserving the bath in a fluid condition-is solely dependent upon
the contents of foreign matter, silicium, manganese, carbon and so forth, which
contents must be larger in proportion as the refining operation is to be carried
on further, seeing that, as the foreign matter is being eliminated, the fusing
point of the iron is raised.
The simplest and most economical process consists in withdrawing the pig
iron directly in its liquid state from the blast-furnace, as however the working
process very frequently varies, the percentage of foreign matter contained in the
pig iron, especially that of silicium, forming the most efficient heating body,
naturally also changes. The working of the blast furnace, moreover, is the
least expensive if serving for the production of white pig iron containing only a
quantity of silicium varying between 03 and 08 per cent. or thereabouts, an
amount which is insufficient for carrying out the ordinary Bessemer process
with cold compressed air. Thus in the case of refining in the acid-converter, a
grey pig iron containing from two to three per cent. of silicium, and in the case
of refining in the basic converter a grey pig iron containing from two to three
per cent. of phosphorus, is produced.
In the former product the noxious body, namely sulphur, is retained from the
iron by the basic slag in the blast furnace, whereas to the latter product a quantity
of from 15 to two per cent. of manganese is added for the purpose of eliminating
the sulphur.
All these operations tend to increase the work and it is desirable to dispense
with the necessity of such operations. This problem may be considered as solved,
as soon as the preliminary refining of a pig iron of 03 per cent. of silicium can
be effected in a converter in a manner yielding a sufficiently high temperature,
so that the iron bath, after the combustion of the greater part of silicium and
of carbon up to 10 or 15 per cent., is still so fluid, that, when having been

page_text: passed over into another converter or into a hearth smelting-furnace it can,
within a sufficiently short time, be ready-refined to iron or to steel in fusion, so
that twice as many charges may be carried out per day in a hearth furnace, than
in the case of inserting pig iron, that, moreover, the temperature admits of being
so regulated, as not to rise too high, in order not to have too destructive an
effect upon the refractory lining, if, owing to the fluctuations in the working of
the blast furnace, the pig iron should contain more than 1 per cent. of silicium,
and that after the operation of preliminary refining being finished or during an
interruption in the said operation, the sulphur is eliminated.
For this purpose a converter for preliminary refining is arranged as near as
possible to the blast furnace, the liquid pig iron being passed from the latter into
the converter by means of a gutter or conduit, if possible without the use of an
intermediate pan, and being refined by blowing hot compressed air into and over
the product. As this hot compressed air is most inexpensively supplied by the
furnace blasts and by air heating devices, it is drawn from the general
conduit, and, as in this latter the tension of pressure is in most cases con-
siderably lower than is required in case of a Bessemer converter with feed
through the bottom, the converter for effecting the preliminary refining receives
lateral air-feed nozzles located below or above the top surface of the bath.
The temperature of the compressed air of the blast furnace, in most cases varies
between 500 and 1000 degrees Centigrade, but, as in case of the pig iron
containing too high a percentage of silicium the temperature in the converter
for preliminary refining is to be lowered, therefore, in addition to the conduit
for conveying hot air from the heaters, a second conduit passing direct from
the blast to the converter, is arranged, so that by way of mixing hot air with
cold air by the proper regulation of dampers arranged for this purpose, any
desired temperature up to 1000 degrees Centigrade can be produced prior to the
entering into the converter, whereby the working of the process can be regulated.
If nevertheless the temperature in the converter for effecting the preliminary
refining should become too high, it is as a matter of experience, not suitable to
cool the air below 150 degrees, because then an incomplete combustion would
take place and too large a quantity of free oxygen would be thus lost, therefore,
in this case an oxydizing body must be added, which in yielding oxygen will
disengage a smaller amount of heat than the air, and this oxydizing body consists
of a metallic oxide, for instance iron oxide, such as is present in iron ore or in
so-called hammerslag or scales of iron: such metallic oxide yields about two
thirds of free heat less than the air and is introduced into the blast converter in
a pulverized form together with the blast air.
For effecting the desulphuration it is preferable, that after the termination
of the preliminary refining operation, the slag be discharged from the converter,
in which the preliminary refining is effected, that subsequently a quantity of
manganese or of iron containing manganese, in either case corresponding to the
percentage of silicium, is added, which rapidly combines with the sulphur,
because of the iron bath being very hot and rises to the surface in the form of
sulphate of manganese, so that it admits of being discharged like the slag, the
iron thus having undergone the preliminary refining is then, according to its
percentage of phosphorous, ready for further treatment either in the basic
Bessemer converter or in the hearth-furnace.
In order to make our invention more clear we refer to the accompanying
drawings, in which similar letters denote similar parts throughout the several
views and in which :-
Figure 1 is a diagrammatical view of a plant comprising a blast furnace, a
fixed converter, a hearth furnace, and a basic converter the latter being indicated
by dotted lines only;
Figure 2 is a plan of said plant;
Figure 3 is a view similar to Figure 1, an intermediate pan being added, the
superfluous or subordinate parts being left out;

page_text: Figure 4 is a plan of the parts shown in Figure 3;
Figure 5 is a view similar to Figure 3, there being two intermediate pans
instead of one.
Figure is a plan of the parts shown in Figure 5;
Figure 7 is a view smilar to Figure 1, the fixed converter being replaced by a
portable one;
and
Figure 8 is a plan of the parts shown in Figure 7.
To carry the above described process into practice the pig-iron may either be
passed from the blast furnace A (Figures 1 and 2) direct to the fixed converter B
for preliminary refining, and thence into the hearth furnace C or into the basic
converter 1), or into one (Figures 3 and 4) or more (Figures 5 and 6) intermediate
pans E or E E, or the portable converter B (Figures 7 and 8) may be employed,
which latter device commends itself in case of several blast furnaces being used,
seeing that such portable converter admits of being transported from one furnace
10 the other, as well as to the hearth-furnace or to the converter and that the
iron is thus refined with the least possible amount of heat being lost. To insert,
however, an intermediate pan is likewise here admissible, if the number of
blast furnaces is so great that the transport of the converter to the steel works
would occupy too much time for effecting the required number of charges per day.
Having now particularly described and ascertained the nature of our said
invention and in what manner the same is to be performed, we declare that what
we claim is :-
1. The process for effecting the preliminary refining of pig-iron, characterised
by passing the pig-iron in its liquid state directly from the blast-furnace into
a converter and blowing hot air into the product in said converter, substantially
as described.
2. The process for effecting the preliminary refining of pig-iron, characterised
by passing the pig-iron in its liquid state directly from the blast-furnace into
a converter and blowing a mixture of hot and cold air into the product in said
converter, substantially as described.
3. The process for effecting the preliminary refining of pig-iron, characterised
by passing the pig-iron in its liquid state directly from the blast-furnace into
a converter and blowing hot air over the product in said converter, substantially
as described.
4 The process for effecting the preliminary refining of pig-iron, characterised
by passing the pig-iron in its liquid state directly from the blast-furnace into
a converter and blowing hot air over the product at the upper part of the same
in said converter, substantially as described.
5. The process for effecting the preliminary refining of pig-iron, characterised
by passing the pig-iron in its liquid state directly from the blast-furnace into
a converter, adding an oxidizing body to the product, and blowing air into the
whole whilst in said converter, substantially as described.
6. The process for effecting the preliminary refining of pig-iron, characterised
by passing the pig-iron in its liquid state directly from the blast-furnace into
a converter, adding iron-oxide to the product, and blowing air into the whole
whilst in said converter, substantially as described.
7. The process for effecting the preliminary refining of pig-iron, characterised
by passing the pig-iron in its liquid state directly from the blast-furnace into
a converter, blowing hot air into the product and adding manganese to the
latter, substantially as described.
8. The process for effecting the preliminary refining of pig iron, characterised
by passing the pig-iron in its liquid state directly from the blast-furnace into
a converter, blowing hot air over the product and adding metallic manganese
to the product, substantially as described.
9. The process for effecting the preliminary refining of pig-iron characterised
by passing the pig-iron in its liquid state directly from the blast-furnace into

page_text: a converter, blowing hot air into the upper part of the product in said converter
and adding metallic manganese to the product, substantially as described.
Dated this 1st day of July 1899.
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C.,
Agents for the Applicants.