WO1996006193A1

WO1996006193A1 - Converters and method of refining metal melts, in particular refining pig iron to steel

Info

Publication number: WO1996006193A1
Application number: PCT/DE1995/001088
Authority: WO
Inventors: Anton More
Original assignee: Anton More
Priority date: 1994-08-20
Filing date: 1995-08-17
Publication date: 1996-02-29
Also published as: DE4429653C2; DE4429653A1; AU3219795A

Abstract

The invention concerns converters and a method of refining metal melts, in particular pig iron to steel, using a coutercurrent technique. The method is characterized in that converters are used which comprise at least two segments and a slag or mixture of slags is introduced into the last or at least the last but one segment of the oxygen converter, the slag having the following chemical composition after being heated to 900 °C: SiO2 + Al2O3 + TiO2 + FeO + MnO 1 to 70 wt.%, SiO2 0 to 15 wt.%, Al2O3 0 to 35 wt.%, Cr2O3 0 to 10 wt.%, TiO2 0 to 7 wt.%, FeO 0 to 70 wt.%, MnO 0 to 20 wt.%, CaO + MgO + CaF2 30 to 95 wt.%, MgO 0 to 15 wt.%, CaF2 0 to 10 wt.%, plus impurities. After melting and reacting with the iron melt and with the oxides arising from oxygen refining, the slag flows in the opposite direction to the iron. Between each of the converter segments is a partition with one or more overflows for the slag and one or more openings near the converter floor for the iron melt. If there are several partitions, i.e. with converters with more than two segments, a gradient exists for the flow of slag through the overflows in the opposite direction to the iron. On completion of the refining treatment, the iron melt preferably leaves the last segment of the converter through a siphon.

Description

Converters and processes for cooling metal melts in countercurrent, in particular from pig iron to steel

The invention relates to converters and a method for refreshing the metal, in particular iron melts, in countercurrent

where without melting slag change with higher

Phosphorus contents can be processed to melts with particularly low P contents.

The demands on unalloyed steels with regard to low P contents have increased continuously in recent years, while the supply of P-poor iron ores is decreasing. From P-poor ores you get a pig iron with about

0.08-0.1% P. Such pig iron can be used in one

Oxygen converter of the usual type melting with about

Blow 0.015-0.010% P If you want P contents of max. If you reach 0.005%, you have to change the slag or you have to use very complex processes with desilication and

if necessary, use partial dephosphorization outside of the converter. Another disadvantage of these methods is

in the fact that additional waste slags arise, deeen

Landfilling is encountering ever greater difficulties.

However, the P content must always be reduced before the iron is actually refreshed with a reduction in the iron content

Scrap rate are bought, which increases the crude steel costs.

There is also a process in which the pig iron is first desilified and then dephosphorized and decarburized in two converters connected in series. In the first converter, pre-phosphate and pre-decarburization are carried out.

The iron is then poured into the second converter, where the fine dephosphorization and the main decarburization take place.

This process, which is the most advanced to date, is also cumbersome and involves high energy losses due to the large number of units required.

Another disadvantage of all common processes is batch operation and the associated temperature change.

The pig iron, which has a temperature of usually 1300-1400 ° C before being refreshed, reaches in the course of

Fresh process despite the addition of cooling scrap temperatures that can go up to over 1800 ° C. This temperature cycle of the iron places a great strain on the refractory lining of the converters, which leads to flaking of refractory material in addition to the corrosive attack of the very aggressive slags on the refractory lining.

We have now found a method with a suitable device which does not have the disadvantages described.

It is a process for tracing iron melts in which the slag flows in countercurrent to the liquid iron.

Other metal melts, such as high-carbon manganese or chromium-containing iron melts can be treated by this method in the devices according to the invention.

In the past, attempts have been made repeatedly to dephosphorize iron with liquid bas. To realize Schlacκe in the countercurrent process. However, all of these methods were too complex in terms of equipment and have therefore not been able to gain acceptance in practice. Surprisingly, this classic problem of iron metallurgy could be solved with a special type of converter which has at least two reaction spaces or segments and has a siphon or a spout pipe reaching to the bottom of the converter, through which the finished melt leaves the converter.

The peculiarity of the converter is that the slag level seen in the flow direction of the iron in the subsequent one

Reaction space or segment is higher. As a result, the slag flow flows in the opposite direction to the flow of iron.

The iron itself flows through openings (foxes) on the floor

the partition or partitions from one segment to another.

It may also be useful to have the individual segments still in

Subdivide chambers in order to be able to carry out various metallurgical steps in a more targeted manner. Segments are integral components of the converter, which can have their own cover and / or have a different level of slag and metal than neighboring segments, for example.

During the best known countercurrent process, the iron is used against the downward flowing by means of an electromagnetic trough

Conveying slag, the method according to the invention does not require any drives.

In the process according to the invention, both the slag and the iron run downwards but in the opposite direction.

This fact, which is also surprising for the person skilled in the art, is achieved in that the reaction spaces are separated off with at least one barrier wall which, in the case of a converter with more than two segments, has overflows for the slag, which have an increasing height when viewed in the direction of flow of the iron, and that the finished treated iron smelting the converter

leave, for example, via a siphon or a pipe reaching the bottom of the converter. The iron melts can also be conveyed out of the converters with another discharge aid, for example by suction with a vacuum or with a mammoth pump.

The overflows for the slag expediently have at least partially water cooling to the level of

Slag level even with progressive wear of the

To keep refractory material constant.

At least part of the slag is on the side of the

Converter abandoned where the outlet for the freshly melted iron is located. After melting, the slag flows over the overflows from segment to segment of the converter against the direction of flow of the iron melts.

The iron melts, on the other hand, come from the side of a pan or a continuously working one

Desulfurization furnace in the converter and flow through various passages at the bottom of the converter according to the invention from one segment or from one chamber to another, in order to finally leave the converter via a sipnon or via a spout pipe reaching to the bottom of the last chamber of the converter.

All or part of the slag or its components can be added in the last segment of the converter. The

Converters according to the invention are preferably designed to be tiltable. If they are not built to be tiltable, they must be cut off. Just by tipping, there is a gradient for the iron between the inlet and outlet of the converter.

In the case of non-tilting constructions, the iron inlet must be higher than the outlet.

The individual segments can have the pear shape customary for converters. For converters that consist of more than two segments, a construction of tubular components is expedient, which can have lids. The cover and / or side walls of the lockers can be above the level of the slag or, if appropriate, above the

Levels of molten metal from water-cooled panels

consist.

The converters according to the invention can be of various types

Variants are built.

1 and 2 shows a converter which consists of 3 segments. The converter of FIG. 3a has 4 of that of FIG. 3b only 2 segments. FIG. 4 shows a further variant of a converter with 4 segments according to the invention. The converter of FIG. 3b is the simplest construction of a converter according to the invention. It can be built from two coupled conventional converters, in that the first converter 26 has a lateral inlet for the pig iron and an outlet for the used slag, and the second conventional converter 27 with a siphon for the finished steel melt

is provided. The two converters are connected to a water-cooled slag overflow 28 and an iron passage 29 at the bottom of the reaction spaces of the converters.

The converter shown in Fig. 4 consists of 4 segments with a circular cross-section. The first segment in the direction of flow of the metal is the forehearth, where the pig iron flowing in is brought to reaction with the hot slag from the second segment 31 while at the same time blowing in oxygen and possibly other fluid substances through one or more floor nozzles. The main reaction and that takes place in the second segment 31

Batching the scrap iron. In the third segment 33, the majority of the slag is added and the fine dephosphorization

carried out. The fourth segment 34 can be designed as a vacuum chamber, where the C content of the iron melt is on the

Low is lowered. The circular design facilitates a vacuum-proof construction of the 4th segment. It can also be useful to build the work spaces of the segments in an elliptical shape or in the form of 2 semicircles with a straight central section (quasi elliptical)

To use mixed construction methods. The cross section of the work spaces of the segments can also consist of semicircles or of

Pitch circles with straight middle pieces.

The construction and operation of the converter according to the invention, which is shown in FIGS. 1 and 2, is described below by way of example.

The first and the last segment of the converter are each divided into two chambers.

The pig iron which flows into the first chamber 1 of the first segment reacts with the slag which flows out of the main reactor 3 via the overflow 2 i.e. the second segment of the converter comes.

At the bottom of the first and second chambers there is a nozzle 4 for blowing oxygen and / or air or an annular nozzle for blowing oxygen and a cooling gas such as natural gas, propane gas, argon, CO, CO or mixtures thereof.

Due to the reaction of the slag from the main reactor and the injected oxygen with the molten iron flowing in, it loses a large part of its Si content. At the same time, their temperature rises. The temperature increase of the molten iron is expediently such that the slag always remains well liquid. At this point, however, the fluxes fluorspar, soda, potash or their mixtures can be charged to liquefy the slag.

After the reaction with the pig iron, the slag flows via the overflow 5 into the second chamber 6, from where it is reacted again with the oxygen from the Floor nozzle 4 whirled iron melt over a

Snout 7 runs out of the converter.

The iron melt heated by the blowing in of oxygen runs through a fox 8 likewise into the second chamber and through a further passage 9 into the main reactor 3.

The volume of the main reactor is larger than that of the pre- and post-reactor.

At the bottom of the main reactor there are injection nozzles 10 for the fluid substances: oxygen, argon, air and / or their mixtures or ring nozzles for oxygen and cooling gases such as natural gas, propane gas, oil, CO, CO ₂ or their mixtures.

In this converter room, an oxygen blowing lance 11 can be used alone or together with the floor nozzles.

In the main reactor of the converter, the temperature of the

Iron melting to the highest value. Temperatures up to over 1750 ° C can be set.

By reacting the molten iron with the slag and

Oxygen can decrease its Si content to values less than 0.03% by weight, and its phosphorus content to values less than 0.02, possibly even less than 0.015% by weight, depending on the initial content of the pig iron.

The carbon content can be set to between 0.5 and 0.015% by weight depending on the flow rate and flow rate of the molten iron per unit time and the oxygen supply per unit time.

During the cooling process, cooling scrap, which can be preheated if necessary, is continuously added to cool the molten iron and protect the converter and to increase the economy of the process. Lime or slag mixtures can also be charged in this segment to bind the iron, manganese and phosphorus oxides that are formed during the fresh process.

Because of the largely continuous process flow, it is advisable to use the waste heat from the converter to preheat the mainly continuously added scrap.

This can increase the scrap rate, which can significantly improve the economics of the process.

After the oxidation of the remaining silicon, part of the manganese and most of the phosphorus, as well as the

extensive decarburization of the molten iron, it flows through a fox 12 into the fourth chamber 13 in the 3rd segment of the

Converter. Here the molten iron reacts with the fresh slag, which consists of components such as mill scale, converter dust, iron ore, manganese ore, bauxite. Lime and / or limestone, used Dolomite and / or raw dolomite, used. Magnesite and / or

Raw magnesite, and possibly fluorspar has been melted. Pelletized mixtures from the abovementioned act particularly favorably. Slag raw materials that have been pre-sintered or preheated. But also finely ground raw material mixtures from the above Slag components that have been preheated, for example, in cyclone heat exchangers can be used. After heating to 900 ° C, the used ones

Slag or raw material mixtures following former analytical values:

and raw material and process-related impurities.

After heating to 900 ° C, the slag or raw material mixtures preferably have the following former analytical values:

as well as raw material and process-related impurities.

These slags or slag components are preferably fed into chamber 5 in the third segment 14.

After melting or as a mixture on the already melted slag, the slag flows from this chamber into the fourth chamber 13. In this chamber, oxygen is blown in from below with one or more nozzles 15, possibly in combination with argon or the other cooling gases already mentioned. In addition, gas or oil burners can be used to melt the slags quickly.

The desired final C content is set in the fourth chamber and the P content is lowered to the lowest value.

After the reaction with the molten iron, the slag then runs through the overflow 16 into the main reactor. The iron melt, on the other hand, flows through the passage 17 into the fifth chamber 14. In this last chamber, the decarburized, dephosphorous and oxysaturated iron is collected. In this chamber, argon or argon together with low-oxygen, bas. Substances such as finely ground, burnt lime are blown in to free the iron melt from the excess oxygen content.

The partition wall 19 between the fourth chamber and the fifth chamber can also be pulled up to the converter edge and closed with its own gas-tight cover. A vacuum can then be applied to the fifth chamber 14 to reduce the oxygen and carbon content of the molten iron. In this case, the slag is fed into the fourth chamber. Finally, the molten iron leaves the converter through a pouring pipe 20 reaching to the bottom of the fifth chamber.

2 shows in particular the level of the slag 21 and the iron melt 22 in the various chambers. Deoxidizing agents and / or alloying materials can already be spooled into the pouring tube by means of Al wire or cored wire.

This allows the deoxidation products to separate quickly.

The molten steel coming from the converter can be collected in a pan or in a pan furnace. However, it can also flow immediately into the distributor of a continuous caster

Another advantage of the method according to the invention is that pans of almost any size can be poured, whereas this is not possible in normal converter operation. If a converter has a capacity of

400 t, you can not divide its contents into two pans, each with 200 t, since the casting process from one

conventional converter must not be interrupted. With the converters according to the invention only one is needed

Tilt the converter back a little and you can change the pan without disturbing the process. For example, one pan can be filled in sequence with 20 t, the next with 400 t of molten steel.

The process according to the invention can be combined very advantageously with the process according to DP 42 06 091 for desulfurizing pig iron melts. This means that the entire process from pig iron to the finished molten steel can be automated and operated with a minimum of transport work.

The pig iron melt, which comes from the blast furnace in the pipe ladle, is allowed to flow through the desulfurization furnace.

Here, the iron melt is desulphurized to an S content of less than 0.005% and at the same time, for example, from 1300

1400 ° C heated.

The desulfurized pig iron now flows into the converter according to the invention. There it is dephosphorized, decarburized and mixed with scrap, which is simultaneously dephosphorized and desulfurized when it is melted down. At the outlet from the converter, the molten steel is already deoxidized and runs directly into the tundish of a continuous casting plant.

This extremely inexpensive way of working is possible because the steel melt leaves the converter so low in sulfur after the combination of the two processes mentioned that slag work is no longer necessary for further desulfurization. Nevertheless, you will normally go into a pan after the converter before the melt is poured. In a pan oven you can combine the above

Desulphurization process with the fresh process according to the invention and the same slag for many taps

can be used, since it is not contaminated by moving converter slag or by an excessively high S content of the iron melt.

An essential advantage of the converter according to the invention is that the steel melt is separated from the converter slag by the siphon. This is the case with conventional converters despite the variety of very sophisticated devices for retaining the converter slag

Tapping is never 100 percent possible. Due to the exact separation of the converter slag, considerable amounts of

Deoxidants can be saved.

Since no converter slag runs into the pan, there can be no resumption of phosphorus from the pan slag.

The polluted P-containing slag in turn leaves the converter free of iron granules. Usually the converter slag still contains a considerable percentage of iron granules, which reduces the iron yield.

Converter slag according to the prior art can only in

Road construction can be used for filling measures.

In the method according to the invention, however, either one falls

Slag, which has hydraulic properties and can therefore be used as a cement additive or very high

P content of the slag i.e. When fresh iron containing high levels of P is fresh, the slag can be processed into fertilizers.

Slags with hydraulic properties which are obtained in the process according to the invention preferably have the following

former analysis values:

and raw material and process-related impurities.

The process according to the invention is therefore also environmentally friendly since there is no slag which has to be deposited.

The energy balance of the method according to the invention advantageously stands out from the methods according to the prior art, with the aid of which it is possible to make P-rich pig iron

Steel with max. Melt 50 ppm phosphorus.

All known methods that have been successful in practice either work with 2 slags or more

single units and 2 slags connected in series. Energy is consumed in each of these units.

Due to the mostly cumbersome and time-consuming manipulation when transporting the iron from one unit to another,

the molten iron cools down and energy is lost. The discontinuous mode of operation is also more conventional

Converter causes energy losses because the heat radiates from the converter opening during charging, tapping and slag removal. In the method according to the invention, on the other hand, all the sub-steps are carried out within a converter which is relatively small in relation to its output and therefore has little heat-emitting surface.

The conventional converters are open at the top, which leads to high radiation losses. The converters according to the invention, however, can have covers. Through openings in the lid, scrap and aggregate such as slag components or fuels such as coke can be fed in and the exhaust gases from the converter can be extracted.

The used slag flows out of the converter evenly. The heat content of the used slag can be used to heat air. This heated air can be used in the afterburning of the converter exhaust gases.

The heat from the post-combustion can be used to preheat scrap that is more or less evenly charged into the converter.

The preheating of the scrap can be carried out in a shaft furnace. The flue gases from the shaft furnace for preheating the scrap can occasionally contain small amounts of pollutants such as dioxins and furans from the incomplete combustion of impurities in the scrap used.

These exhaust gases can be passed into cyclone heat exchangers, for example, which can have an additional heater in which the finely ground slag raw materials are preheated or calcined or burned before charging into the converter. The pollutants mentioned are largely absorbed by the finely ground slag raw materials and then burn in the

Converter. Other pollutants from the converter exhaust gases such as HCl or SO ₂ can also be bound by the lime contained in the slag raw materials

However, the main contamination of converter exhaust gases is converter smoke. It mixes in the cyclone heat exchangers with the finely milled slag raw materials, is largely removed from the converter smoke and returned to the converter together with the slag raw materials.

The used slag from the converter, on the other hand, can flow, for example, onto a water-cooled swinging chute, where it solidifies and can then be cooled by air in a satellite or moving grate cooler.

The used converter slag can also be dusted with compressed air, solidified on a water-cooled vibrating conveyor trough and then cooled with air.

Through these closed cycles practically all energy usable in the process is recovered, whereby the energy balance of the method according to the invention is considerably more favorable than that of the prior art,

In terms of performance, the converters according to the invention are superior to the conventional ones, since the time-consuming manipulations such as charging, parting off and slagging are eliminated by the predominantly continuous mode of operation.

With the same capacity, you can therefore use at least one

According to the invention, 50% higher power can be calculated compared to conventional converters.

The converters according to the invention can also be used for melting and freshening scrap without the addition of pig iron In the simplest case, a converter as shown in FIG. 3b is used for this. The two segments of the

However, converters do not have to have a circular cross section as in the converter from FIG. 3b, but the cross section of the segments can also be elliptical or quasi elliptical, i.e. consist of 2 semicircles with a straight center piece.

The scrap, which can be preheated in a shaft furnace, is charged into the first segment of the converter.

Coke or coal can also be charged in the first segment. Oxygen, possibly together with other fluid substances, is blown in by means of floor jets and / or an inflation lance. The scrap melts and is premixed. The slag, which is given in the 2nd segment, comes over the overflow into the 1st segment. The dosing of oxygen and reducing agents such as coke, coal, natural gas, etc., is carried out so that the slag from the 2nd segment the majority of their

Loses iron oxide content, making it a cement additive

can be used. The iron melt now flows through a fox into the 2nd segment. The 2nd segment can be divided into 2 chambers. The task of

preferably preheated slag raw materials. Oxygen is also blown into the first chamber of the 2nd segment. Here the molten iron reaches its lowest phosphorus and sulfur content as well as the final content of carbon. The iron melt now flows into the second chamber of the 2nd segment. In this chamber, argon or CO, possibly together with lime dust, is injected from below using a nozzle

Free iron melt from excess oxides. The finished steel melt then leaves the converter via a siphon. Design example:

For a better understanding of the method according to the invention, a calculated exemplary embodiment is presented.

It is assumed that the pig iron melt, which is subjected to the fresh process according to the invention, has previously been desulfurized and preheated in a desulfurization furnace according to DP 42 06 091.

This pig iron melt has a temperature of 1450 ° C. when it enters the converter according to the invention.

The converter used according to the invention consists of 4 segments or 6 chambers (Fig.3a).

The 1st segment 35 is a forehearth in which the pig iron is largely desilicated. The main reaction takes place in the second segment 36. Most of the phosphorus and carbon are removed here. The preheated scrap can also be melted here. Fei nentphosphorung and fine decarburization takes place in the 3rd segment 37. In this segment, 70 kg of preheated slag raw materials per ton of pig iron are liquefied. A scrap additive was not taken into account when calculating the slag analyzes. In the fourth and last segment 38, the steel melt is vacuum-treated to break down both oxygen and carbon in order to achieve the lowest carbon contents. Water is also removed during vacuum treatment.

The molten steel, which the converter through to

Leaving spout tube reaching the bottom of the converter is deoxidized as soon as it emerges from this tube by spooling Al wire.

A steel of special deep-drawing quality with the following directional analysis is provided for production in this example:

0.02% C, 0.02% Si, 0.35% Mn, 0.03% AI, max. 0.005% P. The pig iron that comes from the desulfurization furnace and enters the forehearth of the converter (1st chamber in segment 1) has the following analysis:

4 .5% C, 0 .6% S i, 0 .8% Mn, 0. 1 5% P, 0 .005% S.

An annular nozzle is used to enter the first chamber from below

Blown in oxygen together with natural gas or argon.

At the same time, a slag comes from the overflow from the third chamber in segment 2 into the first chamber. This slag has the following former analytical values:

4.0% SiO ₂ , 4.3% P ₂ O ₅ , 40.3% FeO, 4.1% MnO, 0.7% TiO ₂ , 9% Al ₂ O ₃ , 32.3% CaO, 4, 0% MgO.

By reacting the slag with the pig iron, it absorbs SiO ₂ and loses iron oxide. This reaction is completed in the second chamber. From this chamber the used slag leaves the converter via a snout.

The polluted slag has the following former analysis:

22.6% SiO ₂ , 5.5% P ₂ O ₅ , 0.9% TiO ₂ , 11.5% Al ₂ O ₃ , 5.7% FeO,

5.3% MnO, 42.3% CaO, 5.2% MgO.

It flows onto a vibrating channel, where it quickly solidifies and is cooled with air in a moving grate cooler.

For pig iron, the Si content decreases to 0.1% and the C content to about 3.5%. The P content and Mn content of the pig iron remains unchanged.

The temperature of the molten iron rises to 1600 ° C during oxygen freshening. The desilicated iron melt flows through a fox into the second chamber and through another fox into the third chamber in segment 2.

In this chamber, the molten iron is refreshed with an inflation lance and oxygen and / or gases such as argon, natural gas or other hydrocarbons are blown in with floor jets.

At the same time, preheated scrap is charged and melted down, and petroleum coke or coke may be added.

When leaving this chamber, the molten iron has the following previous analysis:

0. 05% C, 0. 02% S i, 0. 35% Mn, 0. 02% P.

It now flows through a fox into the fourth chamber in the

3. Segment 37, which has ring nozzles for blowing in oxygen and argon. The slag raw materials are melted down in this chamber. The following finely ground components are used as slag raw materials:

Limestone, raw dolomite, iron ore, mill scale and bauxite.

The slag raw materials are preheated to about 900 ° C in a cyclone heat exchanger with an additional burner.

The heated slag mixture has the following former analysis:

2% SiO ₂ , 10% Al ₂ O ₃ , 0.8% TiO ₂ , 45% FeO, 36% CaO, 4% MgO.

The P content of the molten iron in this segment is reduced to 50 ppm and the C content to about 200 ppm.

The melt now flows through a fox into the fourth segment 38 of the converter. Here the melt is by means of

Floor nozzles flushed with argon. This segment is gastight built. A vacuum is created, which lowers the C content to approx. 100 ppm while lowering the

Oxygen and hydrogen content in the molten steel.

The molten steel flows from the fourth segment through a pouring pipe reaching to the bottom of the converter into a pan.

When leaving the pouring pipe, such an amount of Al wire is wound into the molten steel that no more Al addition is required in the pan.

Only a small amount of coal is added to the melt to precisely adjust the C content.

Claims

Claims:

1. Converter for freshening metal melts, in particular from pig iron to steel

- at least two segments each (1.6; 3; 13.14)

- at least one metal or iron passage (8,9,12,17) and a higher slag passage (2,5,16) in the partitions between the segments,

a metal inlet (23) and a slag outlet (7) on the inlet side of the metal,

- A slag addition (24) and a metal drain (20) seen in the last segment of the converter in the flow direction of the metal.

2. Converter according to claim 1, characterized in that a central segment (3) has a larger volume than the adjacent segments (1,6; 13,14).

3. Converter according to claim 1 or 2, characterized in that at least one segment is divided by a partition (19) with a metal passage (8; 17) and a slag passage (5; 25).

4. Converter according to one of claims 1 to 3, characterized

characterized in that the height of the slag passages (16, 2) between the addition of slag (24) and the slag drain (7) decreases from segment (13, 14) to segment (3; 1.6).

5. Converter according to one of claims 1 to 4, characterized

characterized in that at least one slag passage (2,5,16,25) is designed as an overflow.

6. Converter according to one of claims 1 to 5, characterized by segments provided with lids (1,6; 3; 13,14).

7. Converter according to one of claims 1 to 6, characterized

characterized in that the segments (1,6; 3; 13,14) are at least partially equipped with nozzles (4,10,15,18) or a lance (11) for introducing fluid substances.

8. Converter according to one of claims 1 to 7, characterized

characterized in that the direction of flow of the metal

seen last chamber (14) or the last segment (13, 14) with the metal drain (20) is connected to a vacuum system.

9. Converter according to claim 8, characterized in that

the adjacent segment or the adjacent chamber (13) is provided with the addition of slag.

10. Converter according to one of claims 1 to 9, characterized

characterized in that the metal drain from a siphon

(20) exists.

11. Converter according to one of claims 1 to 10, characterized by a central segment (3) and two adjacent segments, each divided into chambers (1,6; 13,14).

12. Converter according to one of claims 1 to 11, characterized

characterized in that two segments (13, 14, 3; 1.6) face each other.

13. Converter according to one of claims 1 to 12, characterized

characterized in that the converters are tiltable.

14. Converter according to one of claims 1 to 13, characterized

characterized that the overflows for the slag

are at least partially water-cooled.

15. Converter according to one of claims 1 to 14, characterized in that these consist of tubular sub-elements (segments) which may have lids.

16. Converter according to one of claims 1 to 15, characterized

characterized in that the covers and / or side walls of the converters consist entirely or partially of water-cooled panels above the level of the metal melts.

17. Converter according to one of claims 1 to 16, characterized

characterized that the working spaces of the segments

Have cross-sections that are circular or semi-circular or elliptical or quasi-elliptical, i.e. consist of 2 semicircles with straight middle pieces or of partial circles with straight middle pieces

put together or that mixed construction methods are used

18. A method for refining molten metal, in particular from pig iron to steel, using a converter according to one of claims 1 to 17, characterized in that metal and slag are guided in countercurrent to one another.

19. The method according to claim 18, characterized in that

the height of the slag level decreases in the flow direction of the slag from segment to segment.

20. The method according to claim 18 or 19, characterized by the use of a slag with an initial composition, which was determined after heating the slag to 900 ° C and has the following former analytical values

including impurities

21. The method according to any one of claims 18 to 20, characterized by the use of a slag with an initial composition which was determined after heating the slag to 900 ° C and has the following former analytical values:

including impurities

22. The method according to any one of claims 18 to 21, characterized by an end slag with the following former analytical values:

including impurities.