Process for the production of steel

A charge including scrap, sponge iron and ferrous metals is admitted into the top of a vertically arranged melting column and descends through the latter by gravity. The charge is melted by directing a flame against the leading end thereof and the melt flows through an outlet at the bottom of the melting column in to a chamber located beneath and communicating with the melting column. In this chamber, reduction of the slag is effected and the slag is removed from the molten metal. Alloying additions and deoxidizing agents are introduced into the chamber so that the molten metal is deoxidized and becomes alloyed to produce steel having a desired analysis. The thus-produced steel is superheated in the chamber and is then continuously cast.

BACKGROUND OF THE INVENTION 
The invention relates generally to the production of steel and, more 
particularly, to a method and arrangement for the continuous production of 
steel. 
A method for melting scrap, particularly steel scrap, is described in the 
German Pat. No. 1,800,610. Here, scrap is admitted into a vertically 
arranged melting chamber so as to form a column of scrap. The scrap is 
melted by directing a flame against the scrap column from beneath the 
latter. The cross-section of the column of scrap remains substantially 
constant and, in order to melt the scrap, a flame of plate-shaped 
configuration is used which is centered with respect to the cross-section 
of the scrap column. The flame extends across the major portion of the 
cross-section of the column of scrap. The plate-shaped flame is located so 
far above the bottom of the melting chamber that the liquid melt which 
flows off is able to accumulate to some extent over the bottom of the 
melting chamber and thus serve as a heat-insulator for the heat-resistant 
lining of the latter. The flame is produced with the aid of a lance burner 
which is located on the axis of the melting chamber and which either 
extends through the scrap column or extends into the melting chamber 
through the bottom thereof. 
In this method, the melt which flows off may be fed directly into a 
container which accommodates liquid pig iron in order to be then further 
processed. The further processing of this starting metal, namely, melt and 
pig iron, is conventionally performed by transporting the container with 
the starting metal to a Siemens-Martin furnace, an electric furnace, a 
converter or the like and then introducing the starting metal into the 
furnace or converter. 
The above-outlined method has the disadvantage that the liquid starting 
metal is superheated to only a relatively slight extent. Thus, it is 
possible to hold this starting metal in the container for only short 
periods of time without the formation of incrustations and, consequently, 
the liquid starting metal may be transported over only relatively short 
distances. Moreover, this method is suitable only for the production of 
steel on a batch-type or discontinuous basis. 
In the publication "Stahl und Eisen," volume 92, pages 515-518, (1972), it 
has been proposed to combine the continuous scrap-melting operation 
according to the German Pat. No. 1,800,610 with a continuous process for 
the production of pig iron such as, for instance, in a cupola furnace. In 
this manner, it was intended to arrive at a continuous steel production 
process wherein purification, refining, superheating, alloying and 
deoxidation must follow in a continuous operation. However, here there 
exists always the precondition that pig iron which comes, for example, 
from a blast furnace or a cupola furnace, must be used. This leads to the 
disadvantage that the process is inherently tied in to the use of furnaces 
of this type. 
Further steel production processes are also known from the publication 
"Stahl und Eisen," volume 60, pages 1146-1153 (1970) according to each of 
which a reaction chamber is provided for the boiling out of impurities 
from, or for the purification or refining of, the continuously flowing pig 
iron-like material. Here, it is further necessary to blow with, or blow 
in, oxygen for the purifying or refining operation. A precondition for all 
of these processes is likewise the provision of pig iron. Scrap is added 
in these processes but the only purpose of the scrap additions is as a 
cooling agent for the continuously purified pig iron. However, another 
disadvantage of these steel production processes, which are reliant upon 
the provision of continuously flowing pig iron, resides precisely in the 
fact that the continuous or regulatable introduction of cooling scrap is 
one of the unsolved problems associated therewith. 
SUMMARY OF THE INVENTION 
It is, therefore, a general object of the invention to provide a novel 
process and arrangement for the production of steel. 
Another object of the invention is to provide a novel process and 
arrangement for the continuous production of steel. 
A further object of the invention is to provide a method and arrangement 
whereby the production of steel may be carried out without the use of pig 
iron. 
It is also an object of the invention to provide a method and arrangement 
whereby continuous further processing of melted scrap without the addition 
of pig iron may be achieved. 
An additional object of the invention is to provide a method and 
arrangement whereby steel may be produced more simply and economically 
than was possible heretofore. 
The foregoing and other objects are realized, according to the invention, 
by a process for the production of steel, particularly for the continuous 
production of steel, wherein an iron-containing charge is admitted into a 
first zone and is melted in this zone so as to obtain an iron-containing 
molten metal. The molten metal is introduced into a second zone which 
communicates with the first zone and alloying additions are admitted into 
the second zone so as to effect alloying of the molten metal in the second 
zone and thereby obtain in the second zone a steel having a desired 
analysis. 
Advantageously, the charge used in the process for the continuous 
production of steel according to the invention contains scrap, iron sponge 
or the like and corresponding ferrous metals. It is further of advantage 
in accordance with the invention when the first zone or melting chamber is 
arranged in a vertical orientation and the charge is introduced into the 
melting chamber in the region of the upper end thereof so that a column of 
the charge is formed. This column may descend downwardly through the 
melting chamber by gravity. Preferably, melting of the charge is effected 
by directing a flame at the leading end of the charge column, that is, at 
the bottom of the charge column, so as to obtain continuous melting of the 
charge. The flame, which is favorably of plate-shaped configuration, is 
advantageously directed onto or against the bottom of the charge column 
from below the same. It is further favorable when the flame is 
substantially centered with respect to the cross-section of the charge 
column and extends over a major portion of this cross-section, which 
latter may remain substantially constant. It is of advantage when the 
flame is positioned some distance above the bottom of the melting chamber 
so that the melted charge may accumulate on the bottom of the melting 
chamber to at least some extent and thus provide heat insulation for the 
heat-resistant lining in the melting chamber. 
In general, it is particularly advantageous, in accordance with the 
invention, when the charge is continuously melted from below in some 
suitable manner. The entire melt, that is, the molten metal and the slag, 
may be introduced into the second zone or receiving chamber. The receiving 
chamber is favorably heated and it is preferable when a continuous 
separation of the slag from the molten metal is effected in the receiving 
chamber. The molten metal may be superheated in the receiving chamber and, 
by the addition of suitable deoxidizing agents and alloying additions to 
the molten metal, the desired steel analysis may be obtained in the 
receiving chamber. 
The charge is strongly oxidized during the melting operation. As a result, 
undesirable or impurity components are able to burn off so that 
purification or refining may occur during the melting operation thereby 
making it unnecessary to subsequently boil out such components. 
As a consequence of the continuous operation, a substantially constant 
temperature may be maintained in the melting chamber. This is favorable 
for the heat-resistant material forming the lining of the melting chamber. 
Moreover, the heat-resistant material may be covered by accumulated liquid 
metal, this leading to the advantage that adherence of the slag to the 
heat-resistant lining may be thereby avoided. 
Thus, by using the process according to the invention, it becomes possible 
to continuously produce steel from scrap in an economical manner. 
Reduction of the slag may also be carried out in the receiving chamber. The 
superheating of the molten metal and the reduction of the slag are 
advantageously carried out by electrical means. Where the charge is clean 
or of such purity that an additional or special metallurgical refining 
operation is superfluous and it is only necessary to melt the charge and 
alloy the molten metal in accordance with the desired steel composition, 
the heating required to superheat the molten metal may, after separation 
of the slag from the latter, be performed by induction and in a receiving 
chamber which has been adjusted so as to have basic conditions therein. On 
the other hand, where additional slag and FeO reduction are carried out in 
the receiving chamber, it is of advantage when superheating of the molten 
metal is accomplished by means of an electric arc. 
The steel obtained in the receiving chamber may, with advantage, be 
continuously cast. It is further of advantage when this steel is 
introduced into a continuous casting process. 
The invention further provides an arrangement for the production of steel, 
particularly for the continuous production of steel, which includes means 
defining a melting chamber having an inlet for a charge to be melted and 
means for melting the charge in the melting chamber. The arrangement 
further comprises means defining another chamber for receiving molten 
metal from the melting chamber, and this other chamber communicates with 
the melting chamber. Means for heating the other chamber is also provided. 
The arrangement may also include means for admitting alloying additions 
into the latter chamber so as to effect alloying of the molten metal 
therein and thereby obtain in this chamber a steel having a desired 
analysis. 
The arrangement in accordance with the invention is particularly 
well-suited for carrying out the process of the invention. The melting 
chamber may be arranged in a vertical orientation and the melting means 
may, for instance, be a lance burner which extends along the vertical axis 
of the melting chamber. Such a lance burner may extend into the melting 
chamber through the bottom thereof or it may extend through the charge 
column formed in the melting chamber. In any event, it is advantageous for 
the melting means or burner to be arranged in such a manner that the flame 
generated thereby is directed against the leading or lower end of the 
charge descending along the melting chamber. 
The receiving chamber may be located beneath the melting chamber and the 
melting chamber may be provided with an outlet for the melt in the bottom 
thereof via which communication may then be established between the 
melting chamber and the receiving chamber. The receiving chamber, which is 
favorably capable of being heated, is preferably mounted for tilting 
movement and is advantageously releasably connected with the melting 
chamber so as to permit the receiving chamber to be interchanged with 
another such chamber. It is of particular advantage when, in accordance 
with the invention, the receiving chamber is provided with means for 
separating slag from the molten metal. 
The volume or capacity of the receiving chamber is advantageously matched 
to or selected in dependence upon the melting capacity of the melting 
chamber. Preferably, the capacity of the receiving chamber is chosen in 
such a manner as to permit the molten metal to have an average dwell time 
of about five minutes therein in the event that only superheating of the 
molten metal is required and so as to permit the average dwell time of the 
molten metal therein to be up to about twenty minutes if both superheating 
and slag reduction are necessary. 
It is further advantageous when suitable coupling means is provided between 
the melting chamber and the receiving chamber for minimizing or preventing 
the infiltration of air. 
The advantages of a continuous operation may be fully utilized by 
proceeding in accordance with the invention. The receiving chambers may be 
comparatively small relative to the particular production output as 
determined by the melting chamber or melting means. Consequently, low 
consumption values may be realized as regards the heat-resistant materials 
used and, in addition, favorable metallurgical superheating and separation 
conditions may be obtained. Furthermore, there exists the possibility of 
operating either with concurrent flow or movement or with countercurrent 
flow or movement. Also, since the depths of the baths may thus be small 
and since, in addition, a truly effective and good movement of the baths 
may be obtained, it is possible to achieve almost ideal thermal 
efficiencies. 
The novel features which are considered as characteristic for the invention 
are set forth in particular in the appended claims. The invention itself, 
however, both as to its construction and its method of operation, together 
with additional objects and advantages thereof, will be best understood 
from the following description of specific embodiments when read in 
connection with the accompanying drawings.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
Referring now to FIG. 1, the arrangement illustrated therein may be seen to 
include a melting chamber indicated generally at 20 and a tiltable 
receiving chamber indicated generally at 21. For reasons which will become 
apparent as the description proceeds, the receiving chamber 21 may be 
regarded as a flow-through chamber. 
The melting chamber 20, which may be seen to be vertically oriented, is of 
substantially cylindrical configuration interiorly thereof and the 
diameter of the melting chamber 20 may increase gradually in downward 
direction of the same. The melting chamber 20 has an opening at the upper 
end thereof for charging materials to be melted and, in the region of this 
opening, there is located a bell-shaped distributing device 3 which is 
provided primarily for the event that fine scrap or pre-reduced iron 
sponge is to be melted. A conveyor band 2 conveys material to be melted to 
the upper end of the melting chamber 20 and into the distributing device 
3. Such material may include scrap, for example, steel scrap, compacted or 
uncompacted iron sponge, compacted or uncompacted pre-reduced pellets, 
ferrous metals and the like. From the distributing device 3, the charge to 
be melted is continuously admitted into the interior of the melting 
chamber 20. In this manner, a column of the charge may be formed in the 
melting chamber 20. 
A lance-shaped oil-oxygen burner 1 extends into the interior of the melting 
chamber 20 through the distributing device 3 with the aid of a lance guide 
4. The burner 1 is mounted for movement in axial direction thereof, that 
is, in a vertical direction as indicated by the double-headed arrow, 
thereby enbling the flame generated by the burner 1 to be directed against 
the leading end or bottom of the charge so that the burner 1 may 
continuously melt the charge. As the lower portion or leading end of the 
charge melts, fresh charge is continuously introduced into the melting 
chamber 20 from the distributing device 3 so that there is a continuous 
descent of fresh charge along the melting chamber 20. 
An annular slot 6 is provided in the melting chamber 20. The slot 6 serves 
for the introduction of air into the melting chamber 20 in order to permit 
after-burning of the waste gases generated by the melting operation. The 
resulting combustion gases serve to preheat the charge to be melted. The 
melting chamber 20 also communicates with a conduit 5 through which the 
spent exhaust gases may be withdrawn from the interior of the melting 
chamber 20. 
It may be seen that the melting chamber 20 includes an upper portion and a 
lower portion 7. Both the upper and lower portions of the melting chamber 
20 are lined with a heat-resistant or fire-resistant material. The lower 
portion 7 of the melting chamber 20 is removably secured to the upper 
portion thereof and the lower portion 7 is provided with an outlet passage 
17 through which the melt produced in the melting chamber 20 may leave the 
same. 
The melt, that is, molten metal and slag, leaving the melting chamber 20 
via the outlet passage 17 flows into the receiving chamber 21 through the 
opening 23. The receiving chamber 21, which is located beneath the melting 
chamber 20, is advantageously constructed so as to be interchangeable and 
is preferably arranged in releasable relationship with the melting chamber 
20. It may be seen that the receiving chamber 21 is provided with a 
skimmer 11 which divides it into two communicating accumulation sections, 
namely, a smaller or more shallow section which is located to the left of 
the skimmer 11 in the drawing and a larger or deeper section which is 
located to the right of the skimmer 11 in the drawing. The molten material 
flowing from the melting chamber 20 into the receiving chamber 21 thus 
initially enters the smaller, more shallow section of the latter. As 
schematically illustrated, the slag segregates from and floats on top of 
the molten metal in the smaller section of the receiving chamber 21 and 
the thus-accumulated slag flows out of the receiving chamber 21 and into a 
suitable container 18 via a slag outlet 12 provided in the receiving 
chamber 21. The heavier molten metal, on the other hand, is able to enter 
the larger section of the receiving chamber 21 through the gap defined 
between the skimmer 11 and the bottom of the smaller section of the 
receiving chamber 21. 
The receiving chamber 21 is lined with a high-grade heat-resistant 
material. At the larger section thereof which is provided for accumulation 
of the molten metal or the steel, the receiving chamber 21 is provided 
with an induction coil 14. The coil 14 enables the molten metal or steel 
accumulated in the larger section of the receiving chamber 21 to be heated 
or superheated by induction. 
A feeder 10 is provided and serves for the introduction of alloying 
additions and deoxidizing agents into the receiving chamber 21 and, hence, 
into the molten metal accomodated in the latter. In this manner, the 
composition of the molten metal in the receiving chamber 21 may be 
adjusted so as to obtain the desired steel analysis. 
The receiving chamber 21 is provided with a steel outlet 13 via which steel 
having the desired analysis may be removed from the receiving chamber 21. 
As a result of the continuous introduction of molten material into the 
receiving chamber 21, steel is continuously flowing out of the latter 
through the outlet 13. Advantageously, the steel leaving the receiving 
chamber 21 is continuously cast and, preferably, the steel leaving the 
receiving chamber 21 is introduced into a continuous casting operation. In 
order to permit the receiving chamber 21 to be completely emptied, an 
emptying outlet or tap 15 is provided in the receiving chamber 21. 
To prevent entry of infiltrated air into the melting chamber 20, a seal 9 
is provided between the melting chamber 20 and the receiving chamber 21. 
The seal 9 may, for instance, have the form of a sand pocket. 
This embodiment of the invention is well-suited for continuous superheating 
of the molten metal where the charge is clean, that is, of such purity 
that a special or additional metallurgical purification or refining 
operation is superfluous. In such an event, the conditions in the 
receiving chamber may be adjusted so as to be basic and superheating of 
the molten metal by induction may be carried out under basic conditions. 
The capacity of the receiving chamber is advantageously between about 5 
and 20 tons. The requisite introduction of alloying and deoxidizing 
additions may be carried out continuously. 
Coming now to the arrangement illustrated in FIG. 2, it may be seen that 
the same reference numerals as in FIG. 1 have been used to designate 
similar components. The arrangement of FIG. 2 includes a melting chamber 
20 as described above. Here, however, the receiving chamber is designated 
with the reference numeral 22 and it will be appreciated that the 
receiving chamber 22 differs from the receiving chamber 21 of FIG. 1. The 
receiving chamber 22 is mounted for tilting movement and is provided with 
a cover. In contrast to the embodiment of FIG. 1, where the induction coil 
14 is provided for heating the receiving chamber 21, there are here 
provided electrodes 19 for heating the receiving chamber 22. The 
electrodes 19 permit an electric arc to be generated and directed over the 
melt in the receiving chamber 22. 
The molten metal flowing out of the melting chamber 20 through the outlet 
17 thereof enters the receiving chamber 22 via its opening 23 provided in 
the cover of the receiving chamber 22. A seal 9 is located between the 
outlet 17 and the opening 23 in order to minimize the entry of infiltrated 
air. The slag is removed from the receiving chamber 22 via the slag outlet 
12 located at one side of the receiving chamber 22 and beneath the cover 
of the latter. 
The steel outlet 13 is located at the side of the receiving chamber 22 
opposite that provided with the slag outlet 12 and the finished steel 
leaves the receiving chamber 22 via the steel outlet 13. Again, the steel 
leaving the receiving chamber 22 may advantageously be continuously cast 
and is preferably introduced into a continuous casting operation. In the 
present instance, the steel outlet 13 is downwardly inclined in direction 
from the exterior of the receiving chamber 22 to the interior thereof. The 
steel outlet 13 is here defined between the skimmer 11 and the bottom 
surface of the receiving chamber 22 and it may be seen that the side of 
the skimmer 11 facing this surface of the receiving chamber 22 is also 
downwardly inclined in direction from the exterior of the receiving 
chamber 22 to the interior thereof. The receiving chamber 22 is favorably 
constructed as an interchangeable vessel and is favorably arranged in 
releasable relationship with the melting chamber 20. 
This embodiment of the invention is well-suited for continuous superheating 
of the molten metal in cases where FeO reduction and additional slag 
reaction are carried out. The introduction of alloying and deoxidizing 
additions into the receiving chamber 22 may be carried out continuously 
via the feeder 10. 
It will be appreciated from the foregoing description that the invention 
has provided a process and arrangement which permit steel to be produced 
without the use of pig iron. 
The temperature in the receiving chambers is substantially constant. This 
substantially constant temperature in the receiving chambers permits the 
use of linings made of heat-resistant materials which are entirely basic 
in nature. In contrast, such linings can almost never be used in 
discontinuously operating electric furnaces, particularly induction 
furnaces. Correspondingly, the electric arc heated receiving chamber 32 
may be provided with a cover which is entirely basic in nature. Such 
covers cannot be used in conventional electric arc furnaces where they are 
subjected to high loads due to radical temperature changes. On the other 
hand, since temperature in the receiving chambers is substantially 
constant, the cover for the receiving chamber 22 will not be subjected to 
the high loads generated by radical temperature changes. 
It will be understood that each of the elements described above, or two or 
more together, may also find a useful application in other types of 
processes and arrangements differing from the types described above. 
While the invention has been illustrated and described as embodied in a 
process and arrangement for the production of steel, it is not intended to 
be limited to the details shown, since various modifications and 
structural changes may be made without departing in any way from the 
spirit of the present invention. 
Without further analysis, the foregoing will so fully reveal the gist of 
the present invention that others can, by applying current knowledge, 
readily adapt it for various applications without omitting features that, 
from the standpoint of prior art, fairly constitute essential 
characteristics of the generic or specific aspects of this invention.