MXPA96001876A - A method of reduction of foundry conefectivity increment - Google Patents

Abstract

The present invention relates to a method of increasing the effectiveness of the reduction of smelting of oxidic metal carriers, particularly iron ore, and improving the thermal efficiency of fuels charged in the smelting reduction process taking place in a smelting vessel. reaction containing a melted bath with a slag layer and where the reaction gases escaping from the melted bath are subjected to post-combustion with oxidizing gases, the resulting heat is transferred to the molten bath and the reactive agents, mineral and carbon, are fed to the melt at least partially from the top through the gaseous space of the reaction vessel, where these reactive agents, mineral and carbon are added in a compact form to the molten bath as a composite material with or without additional scololing substances.

Description

A METHOD OF REDUCTION OF FOUNDRY WITH INCREASED EFFECTIVENESS # > Description This invention relates to a method for increasing the effectiveness of reducing the smelting of oxidic metal carriers, particularly iron ore, and improving the thermal efficiency of fuels charged in the process of 'casting deduction, which takes place in a reaction vessel containing a melt bath with a slag layer and where the reaction gases escaping from the melted bath are subjected to post-combustion with oxidizing gases, the resulting heat being transferred to the melted bath, and the reactive agents, mineral and carbon, are fed to the melter at least partly from the top through the gas space of the reaction vessel. New developments in the manufacture of metal from the corresponding metallic minerals seek mainly to use cost-effective reducing agents and energy carriers. For the manufacture of iron, the goal is particularly to replace coke with coal. The reduction of smelting of metallic minerals offers favorable conditions for using coal of various qualities, both to compensate the thermal balance of the process and for the reduction reaction itself. The first methods of smelting reduction are already being applied in industrial practice. To make iron in ingots, we have the COREX process, and for non-ferrous metals, for example for the production of lead, the QSL method must be mentioned. For the COREX process, with its relatively high consumption of carbon and oxygen, economy can be achieved compared to the blast furnace process only if relatively high energy gases are reused industrially. "" The methods of reducing smelting, mainly to make pig iron, in which the supplied fuels are better exploited in the course of the same method, are being developed and have reached the pilot plant stage in some cases. The publication Entwicklungslinien der Schmelzreduktion, by Stahl and Eisen 109 (1989), No. 16, p. 728 a 742, gives a survey of the various developments for the production of pig iron. The term "method of "" smelting reduction "is defined in this article as follows.

"Melted iron will be produced in coke-free metallurgy from iron ore directly, if possible without an agglomeration step, where" ideally "the processes of reduction and smelting take place simultaneously". According to this definition, coal is used instead of coke, and ore or ore powder directly, without pre-treatment, and is carried out without the coke plant, on the one hand, and ore dressing plants, on the other. part. In accordance with these prescribed goals, experts are struggling to develop smelting reduction methods mainly in this direction. As indicated by several recent publications, the known smelting reduction processes that have reached the pilot plant stage at least operate on the basis of the aforementioned ideas. Mainly dust of ore and coal serve accordingly as loading materials. The money can be pre-reduced and heated in a preceding reactor, preferably by exploiting the release gases produced in the melting reactor, and subsequently charged in the melting gasifier. For the pre-reduction step, an arrow oven, a rotary tubular furnace or fluidization can be used. In the CCF process (cyclonic converter oven) the pre-reduction is carried out until wustita in a cyclone of "-" - casting, from which molten droplets fall through the gas space of a cast iron reduction vessel similar to a converter to the slag-iron bath. In the Japanese process GOD (direct casting of iron ore), the solid charge, coal, iron ore and slag forming agents, is first heated in a pre-heating vessel, pre-reduced in a pre-reduction plant and the pre-reduced ore then fed to the reduction vessel of foundry similar to converter. The afterburning of the reaction gases, CO and H2, of the iron melt in the foamed slag layer located above them is carried out in the melting reduction vessel with oxygen supply via a lancet. In addition, nitrogen is passed through lower nozzles for a more intense mixture and movement of the bath. The converter stripping gases can be reformed before leaving the smelting reduction vessel by the addition of grain carbon to treat it for the next application. In the Hlsmelt process, pre-reduced ore from a circulating fluid bed is passed into the drum-type casting reduction vessel, and coal is added through lower nozzles. The reaction gases of the melter are subjected to post-combustion by hot air blown from above into the reactor. Additional solids and also fine grain mineral can be fed into the process through the lower nozzles. The method for intensifying the reactions in metallurgical containers, described in German Patent No. 42 34 974, is particularly useful for increasing the re-transfer of the heat released from the post-combustion of the reaction gases to the molten bath in the reaction vessels. metallurgical It is characterized in which fractions of the melt move in the form of droplets, splashes and large particles of the melt in ballistic flight paths within the gas space of these reaction vessels, being rotated out of the melt as a source through the amount of gases passed inwards via the lower nozzles of the bath. This patented method is applied mainly in the HIsmelt process. European patent application publication number 04 18 927 describes a method for carrying out casting reduction. It is emphasized that a large amount of slag is essential, of at least 2,000 kg / m2 of bathing surface. During the process, the slag exists as foamed slag in a layer thickness of at least 2 m to more than 4 m. The measurement of the height of the slag layer indicates the density of the foamed slag layer, and the addition rates of carbon, oxygen and ore are controlled to maintain the foamed slag layer at the desired density. An additional melting reduction method, where nozzles for decarburization and additional nozzles for post-combustion are arranged in a converter-like vessel, with a top-blowing oxygen lancet, is described in the European patent application publication number 03 08 925. Agitation gas is fed through lower and side wall nozzles for intense mixing and concentration balance in the iron melt and to produce the desired foamed slag on it. All solid cargo materials, such as iron ore, carbonaceous fuels and slag-forming agents, are loaded into the melting vessel on the melt or insufflated via nozzles from the side, if necessary. The prior art includes, to a greater extent, a method and a plant for the continuous production of pig iron, which are described in the German application open to inspection printing number 34 21 878. This method for the continuous production of pig iron from ferrous materials, particularly iron ores, with simultaneous production of a process gas, it is characterized in that the ferriferous materials are fed in the form of green pearls, pellets, crusts or similar to a displacement box and pre-heated , dried and reduced to iron sponge with a degree of reduction of around 90% on it, with the help of the process gas, and the iron sponge is fed from above directly to a coal gasification reactor with an iron bath and melted there with a continuous discharge, separated from > - Jiierro and slag, blowing coal and oxygen into the iron bath in the gasification reactor, preferably from below, and the coal being gasified to a sulfur-free process gas or reducing gas that is fed into the displacement box to reduce , pre-heat and dry the pearls. In the coal gasification reactor of this method there is an over-pressure of about 2 bar, and the hot process gas produced leaves the reactor in the area of its cover and is then fed to a hot gas cyclone for be released from trapped dust. After that, the gas is used in the reduction chamber of the sintering band to reduce the iron ores. The average technician who starts from known methods and looking for an inexpensive way to prepare iron in ingots from iron ore will recognize several disadvantages in these new processes, along with their positive aspects. This discovery is strengthened by the fact that "or a large-scale industry has been put into practice, to date, no process to make pig iron from ore without the use of coke, apart from the COREX method with its disadvantages relating to large quantities of waste gas and considerable oxygen consumption In a synopsis of the prior art, the methods of reducing smelting with high post-combustion of the produced process gases, CO and H2, and good re-transfer of • - heat, show clear advantages in the energy balance. A relatively high dust discharge with the release gas and thus losses of iron and carbon has been shown to be disadvantageous. These disadvantages, of course, must be seen in relation to the way coal and mineral are added. The control of liquid, hot melt constituents trapped by the stripping gas similarly has not been satisfactorily resolved in these process variants. However, as soon as the post-combustion and process reactions take place in a foamed slag, the maintenance of the desired layer of foamed slag with respect to the density and height and the related limitations in the reactions pose new problems. The incentive to apply a method of reducing smelting to make pig iron to improve the economy over the blast furnace process is obvious to the person skilled in the art, especially since it allows to achieve high densities of energy in comparison with other variants of iron. process, particularly if post-combustion of process gas is included, as indicated for example by Howe Memorial Lecture, March 30, 1987, AIME Symposium, Pittsburgh, Pennsylvania, United States. The use of hot air and an advantageous upper inflation nozzle according to German patent No. 39 03 705 have proved to be useful. In this way, a 55% post-combustion degree can be obtained with a re-transfer of heat to the iron melt of 80% in a reproducible and reliable way. The present invention is based on the problem of using the advantages of known melt reduction methods with post-combustion of reaction gas to increase the thermal efficiency of the charged fuels, and to clearly increase the effectiveness of these processes with respect to their economy and reliability to make iron ingots in an effective way from the point of view of costs from iron ore. A synergistic effect which utilizes the advantages of the steps of the known methods without the sum of their disadvantages must be achieved with relatively simple means in reproducible form. The solution to this problem is that the reactive agents, mineral and carbon, are added in a compact form to the melt as a composite material, with or without additional escort substances. The invention is based on the discovery that the intimate contact between the reactive agents, mineral and carbon, in an agglomerate or composite material, leads to a direct reduction reaction between the iron oxide and the carbon. Therefore it is not necessary to first melt the iron ore before the reduction step. The resulting advantages have a particular effect on the reaction rate of the reduction and post-combustion of the reaction gases, CO and H2, on the melted bath. This keeps both foundry reduction methods -with a gas space free of foamed slag, for example the Hlsmelt process, and for post-combustion in a foamed slag, as in the so-called deep slag processes. The discovery that the composite material should be added to the melt in a compact form should be considered as an essential aspect of the present invention. Consequently, it must be ensured that composite or agglomerated materials, for example pearls or pellets, are immersed in the melt as compact units, ie without signs of decomposition or bursting. This requirement has turned out to be significant in order to fully obtain the surprising advantages of the invention, the increased effectiveness of the reduction of smelting of the oxidic metal carriers, particularly iron ore, and the improved thermal efficiency of the fuels charged in the process of cast iron reduction. As soon as the composite material is submerged in the melt in a compact form, the discharge of dust with the melting gas from the melting reduction container is reduced by at least 20%, and the thermal efficiency of the fuels is reduced. supplied improves by at least 10%, which is partly due to the increased post-combustion itself and partly to the improved re-transfer of heat from the post-combustion to the molten bath In accordance with the invention, the agglomerates or Composite materials can be pearls, pellets or compacts - green, dry, pre-burned and pre-reduced or any desired mixtures of these various agglomerates Reactive agents, mineral and carbon, with or without additional escort substances, are added as A composite material in a compact form to the melt in the reaction vessel This essential aspect of the present invention is intended to mean that the carbon content in the agglomerate, by way of a pearl or shot, it is at least high enough to be sufficient for a complete reduction of trapped metal oxide, particularly iron oxide. Furthermore, it is within the scope of the invention to attach additional carbon in the composite material in a free or bound form, for example as a hydrocarbon. This fuel, in addition to the actual reducing agent for the ore, serves to compensate the thermal balance during the operation of the smelting reduction method. In practice, a portion of the fuels is passed to the melt in addition to selective process control "" ", for example via lower nozzles. However, according to the invention, all the amount of fuel required for the process can also be fed to the melt via the composite material. According to the invention, the mineral may exist in the agglomerate in a form of fine grains and / or clusters.

It can be crude ore, pre-reduced ore with varying degrees of reduction, or even complete metallization. Charcoal It can be similarly incorporated in any desired form, for example in the form of coal of various qualities, also with constituents of high volatility. Coke and other carriers of solid carbon and hydrocarbons as well as liquid hydrocarbons in the form of various qualities of oil, tar, bitumen and refinery waste, can be used in composite materials. The quality of the selected coal has turned out to be totally non-critical, which is especially advantageous for the method of the invention. Virtually any available coal can be used, from high grade anthracite to coal grades with a considerable content of volatile constituents, such as gas flame coal. The constituents of coke or coal that are formed after the carbonization and disintegration of coal can vary in size, shape and density. In contrast, coal qualities with high volatile content lead to disadvantages in known methods. For example, the '' spontaneous burst of carbon in the gas space of the reaction vessel is undesirable., because it increases the discharge of carbon particles with the release gas. With the inventive use of composite beads, the agglomerates are immersed deep in the foamed slag before they burst, for example, and the resulting carbon particles are distributed relatively uniformly in the foamed slag layer and contribute to stabilize it. v It has been d, totally unexpectedly and surprisingly, that the inventive use of these agglomerates or composite materials leads to a clear increase in the effectiveness of the methods of smelting reduction. The discharge of dust with the release gas from the melting reduction vessel has been reduced considerably, which implies several additional advantages. The most obvious is a reduction in the iron oxide content in the slag.

When the process is conducted with foamed slag, - there is less free carbon and a smaller number of carburized iron droplets in the foamed slag compared to the known addition of coal and ore. This makes it easier to adjust the foamed slag layer, and clearly higher post-combustion grades can be obtained. The smaller number of reduced droplets and the fractions of melt in the slag make it possible to control the FeO content in the slag, and this relationship in turn leads to a decrease in the gas reduction between the oxidant post-combustion jet and The carbon content in the slag is lower compared to known processes, due to the direct reduction of reactive agents, mineral and coal, in the agglomerate, estimates have shown that the carbon content in the slag can be reduced in this way by about 50% This lower carbon content results in additional benefits due to reduced losses of carbon. < * - coal during slag plugging and in this way a higher output of the fuels supplied. The improved post-combustion, that is, the increased degree of post-combustion of the reaction gases, CO and H2, from the melt at C02 and H20, is probably due, according to the present level of knowledge, to the lower reduction of the post-burned reaction gases through the lower carbon content in the release gas. The lower powder loading rates in the stripping gas first have an effect in the method of the invention and, in addition, the carbon content in the powder has decreased. These two improvements, in the end, make less carbon available in the gas space or foamed slag for reverse reactions with the post-burned release gas. In other words, the post-combusted reaction gases at C02 and H20 find lower carbon-free particles for reduction, ie inverse reaction to CO and H2. This idea can explain the unexpected improvements in the combustion of the reaction gases and in this way the improved thermal efficiency of the fuels charged with the application of the method of the invention. The method of the invention has increased the degree of post-combustion of the reaction gases from 55 to 70% and the heat transfer to the iron melt from 80 to 90% under identical operating conditions in all other respects, both in operation of foamed slag as in free operation of foamed slag. Compared with known addition techniques, mainly by carbon and mineral reactive agents, the method according to the invention has several advantages to carry out a melt reduction process. The energy balance of the method can be fully improved by increased post-combustion and increased thermal re-transfer to the melt. Along with these economic advantages for the method, the casting speed is increased simultaneously and in this way the iron produced per unit of time. These advantages, therefore, increase the effectiveness of the smelting reduction method. Further, it has been found that the steps of the method of the invention also reduce the consumption of refractory materials. The controlled and selective operation of the process, for example avoiding the frequent excesses of temperature in the melt during iron processing, probably has a favorable effect on the wear rate of the refractory lining of the reaction vessel. According to the invention, it has been found to be advantageous to drop the composite materials in the bath from a certain height, but at least 0.2 m above the melt in the casting reduction vessel. When passing through this height of fall, for example at an average speed of 1 m / s or more, the temperature increases, and with it the thermal content of the agglomerates. For this warming of the , > • Compound materials have been proven to be favorable to retain their shape and be immersed in the melt as compact pellets. In other words, the decomposition or bursting of the agglomerates in the gaseous space of the melt reduction vessel is undesirable. According to the invention, the agglomerates or composite materials can have basically any geometrical shapes and dimensions. Cubic shots are as possible as spherical ones. In practice, the usual, more rounded, spherical and oval shapes, for example egg-shaped pellets, have proven useful. The dimensions of these agglomerates can depend on the length of the fall distance from the preheat temperature that can be achieved when they pass through the fall distance. For example, small spherical pellets with diameters of 6 mm at a minimum falling distance of 1 m, and larger pellet diameters of 15 to 50 mm at ^ "large falling distances of up to 10 m can be used. The same as the standard gross value for the maximum average temperature of pre-heating of the composite materials should be taken approximately 200 ° C. This indicated pre-heating temperature can be increased further, however , if they increase, for example, the falling distances of the composite materials.

This can be done, for example, by using the gas systems "" - "- of detachment for pre-heating of the pellets. Composite materials can fall through the waste gas or waste water boiler tube placed on the casting reduction vessel, so that falling distances of 25 m and possibly more can be achieved, corresponding to maximum pre-heating temperatures. -heating up to approximately 500 ° C. A further increase in the preheating of agglomerates above 500 ° C is undesirable. At significantly higher temperatures, there is an increasing likelihood of bursting of agglomerates, for example due to the release of the volatile constituents of the charged carbon. This decomposition or bursting of the agglomerates before their immersion in the melt is not in accordance with the method of the invention. The immersion of the composite material, for example pearls or pellets, in the melt, means in the method of the invention that they are at least completely covered by the melt after immersion, but preferably reach a certain depth of immersion in the melt. In casting reduction methods that work with a foamed slag layer, the minimum immersion depth is approximately 0.5 m, as the thickness of the foamed slag layer can vary greatly, for example from 2 to more of 4 m, the immersion depth can only be defined in coarse form in relation to the height of the foamed slag.For a height "-of the relatively small layer of foamed slag of 2 m, a minimum immersion depth of the materials compounds of 0.5 means, therefore, 1/4 of the height of the foamed slag. Smelting reduction methods that operate without foamed slag, ie in which post-combustion occurs in the free gaseous space above the melt, typically have small slag layer thicknesses of less than 1 m, usually between 0.1 and 0.5 m . The minimum depth of immersion of composite materials is consequently small, but always sufficient for them to be completely covered with slag. After reaching the minimum immersion depth, the agglomerates can be heated until they are partially or completely decomposed, for example due to the volatile constituents released in the carbon. After reaching the minimum depth of immersion of the composite materials in the melt, preferably in its slag layer, the agglomerates - '* "* can decompose.Solid decomposition products, for example particles with high carbon content, contribute to stabilize the foamed slag.In a normal slag layer, ie In the process of reduction of free casting of foamed slag, the particles of the decomposed composite materials are absorbed very quickly by the molten bath, since there is an intense movement in the bath throughout the melt and mixtures of slag and fractions of - "-metal in the border layer. The advantageous application of the method according to the invention for the melt reduction processes operating with a foamed slag layer results in favorable conditions for maintaining and stabilizing the desired foamed slag with a desired average density of approximately 1 g / cm 3. This foamed slag is constantly in motion; a slag flow from the melted bath can be observed towards the slag surface and vice versa, but cross currents also occur at this preferred flow direction. In this foamed slag moving layer, the carbon / coke particles released after the decomposition of the agglomerates in the foamed slag are not collected on the foamed slag surface, as in the known processes, but flow or form stream with the foamed slag itself and they are distributed surprisingly uniformly in it. Due to the higher density of pellets or pellets compared to foamed slag, these composite materials sink into the slag before decomposing and increase the effectiveness of the reaction in the foamed slag. of the pellets have the tendency to adhere to the solid particles, for example coke particles, and to give them additional buoyance, however, it has been found with the application of the method of the invention that a density of the pellets of ~ about 1.5 g / cm3 or more is already sufficient to guarantee the uniform distribution of the carbon / coke particles in the foamed slag, in this way it can reliably prevent the undesirable accumulation of coke particles and their formation on the foamed slag surface as it is known from the usual methods.In known methods, the supplied carbon is totally carbonized before being integrated into the slag as carbon particles. The volatile constituents of the carbon released on the surface of the bath have a reducing effect on the post-combustion gas oxidant jet stream and reduce the degree of post-combustion and thus the thermal balance of the process or the thermal efficiency of the qualities of coal supplied with volatile constituents. For this reason, the content of volatile constituents in the coal grades is limited to less than 20% in the foamed slag methods. In the method of the invention, the release of volatile carbon "" constituents below the surface of the foamed slag bath results in an increase in the effectiveness of the process, since the reducing gases from the decomposition of coal rise in Foamed slag This results in several advantages for the process run The reducing gases, CO and H2, released during the decomposition of coal, and soot fractions come into direct contact with the slag containing iron oxide and / "- lead to the metallization of the iron oxides, and the reducing gases are also available for reaction with the post-combustion oxidant jet stream that partially penetrates the melt. - Burning in the melt is desirable as it contributes to a greater heat transfer of the post-combustion energy to the melt The reaction gases produced additionally from the reaction of the volatile constituents of the coal with the jet stream post-combustion below the surface of the bath lead to an increased and advantageous movement of the bath in the slag.This increased movement of the bath in turn allows the amount of circulating gas through the lower nozzles of the bath to be reduced to adjust the desired heat transport in the slag and the desired density of the foamed slag According to the invention, the density of the slag Compound materials should be set to be greater than the density ^ "of the liquid slag in the melt reduction vessel. For example, it has been found useful to pellet a mixture of mineral powder, coal, lime and a binder under high pressure to achieve a bulk density of approximately 2.0 g / cm3. Shot pellets were produced with approximately the same composition, with a bulk density of 1.6 g / cm3.

With the inventive use of these agglomerates in the smelting reduction vessel, the slag on the iron bath had ? - a composition of 49% CaO, 32% SiO2, 3% FeO, 17% Al203, and in this way a density of 2.6 g / cm3. As foamed slag, the density is reduced to approximately 0.8 g / cm3. The method of the invention has surprisingly reduced the discharge of dust with the release gas from the melting reduction vessel disproportionately. For example, in a pilot plant operated by the Hlsmelt method, about 10 tons of liquid iron per hour are produced. When ore and coal are used, ie without a pre-reduction step for the iron ore, approximately 16 tons of ore powder per hour are fed to the melt, with a composition of 63% Fe, 2.6% SiO2, 1% of Al203, and simultaneously 8 tons of coal with a volatile content of approximately 10%. The post-combustion in the gaseous space free of foamed slag from the container is approximately 50% and the re-transfer of heat (heat transfer efficiency) to the iron bath r * "approximately 80%." Under these operating conditions, The release gas contains approximately 60 g / Nm3 of powder with an approximate carbon content of 15%, however, if the ore powder is passed to the melt from the top through the gaseous space of the casting reduction vessel. together with the carbon for reduction as an agglomerate, particularly a pearl or composite shot, the powder discharge is reduced to 30 g / Nm3 of release gas.

- "- • Simultaneously, the degree of post-combustion is increased under identical conditions in all other respect to 60%, with about 85% of re-transfer of heat to the iron melt.As a consequence, the discharge of dust of a smelting reduction vessel can be reduced by applying the method of the invention by approximately 50% compared to the usual operation of smelting reduction.A maximum dust discharge of about 45 g / Nm3 of stripping gas should be expected. Reduced content of carbon in the powder is a further advantage With the method of the invention, the content of carbon in the release gas powder can be set at values below 8% Before the application of the method of the invention, the content of carbon in the release gas was about 15% with foamed slag, this reduction in the discharge of dust by itself and particularly the reduced carbon content in the powder of the detachment -j as results in advantages when the release gas is used for pre-reduction or pre-heating and mainly in the gas cleaning plant. Together with the improvements described above in the post-combustion of the reaction gases of the iron melt and the simplifications in the adjustment and stabilization of the foamed slag, the improvement in the handling of the release gas itself shows the clear and unexpected advantages in the addition of reactive agents, mineral and coal, as a composite material by means of the method according to the invention. It is conceivable that the increased post-combustion is related to the measurable reduction in the iron oxide content of the slag, mainly when post-combustion occurs in a foamed slag layer. Probably less oxidation reactions occur between the jet stream of post-combustion gas and the slag. The lower content of FeO particles in the slag simultaneously reduces the possibility that the oxidizing gases insufflated from above oxidize the FeO molecules. Simultaneously, the reduced concentration of FeO in the slag causes a clear improvement in the wear of the refractory lining of the reactor. Wear rates of the refractory lining can be reduced by more than half. The reduced FeO content in the slag also results in a higher metal production and thus an increased effectiveness of the process compared to known methods. "The invention will now be explained in more detail with reference to an exemplary drawing and a Non-limiting example: Figure 1 shows a schematic view of the longitudinal section through a converter-like casting reduction vessel in which the process takes place with a layer of foamed slag. "metal 1 has the liner 2, which is penetrated in the lower area by nozzles 3. The upper insufflation lance 4 has upper injection nozzle openings 5 for the oxidation reaction and post-combustion nozzles 6 for post-combustion of the reaction gases, CO and H2.The casting reduction vessel 1 with the lining 2 contains the melted bath 7 whose depth is shown by the arrow 8. On the melted bath 7 is the foamed slag 9, the level of the bath indicated by the arrow 10. Gas bubbles 11 in the melt are marked by consequently small clear areas , while the composite materials 12, beads in this example, which pass to the casting reduction vessel through the feed opening 13 are shown by dark spots. The release gas 14, marked by the small arrows, leaves the melting reduction container through the release gas tube 15. With the release gas 14, the dust particles, including soot and particulate matter. The method of casting reduction in the container shown in Figure 1 works with a foamed slag and a lancet for the upper insufflation of oxygen, as is usual for the so-called deep slag process. solid reagents are fed to the melt through the feed opening 13 in the form of beads 12. The beads - contain 65% iron ore and 25% carbon (composition of approximately 80% C, 10% ash, 10% volatile materials, including 2% H20), as well as 8% CaO as a forming agent scum and binder. They are green pearls with a bulk density of 2.5 g / cm3. The iron melt 7 has a weight of 20 tons at the beginning of the process and at a maximum weight of 40 tons, 20 tons of iron are removed in ingots with a composition of 3.5% C, 95% Fe, from the container through a hole not shown. Simultaneously, 8.5 tons of slag with a composition of 38% of CaO, 27% of SiO2, 17% of Al203, 12% of MgO, 3% of Feox, are removed from the container through a slag hole, either shown During the process, about 700 kg / min of beads 12 are fed into the melt 12. Simultaneously, 7,500 Nm3 / h of oxygen are blown via the lancet 4. Approximately 1,500 Nm3 / h flows through the upper insufflation openings 5 and 6,000 Nm3 / ha through the post-combustion nozzles 6. Through the release gas pipe 15 17,000 Nm3 / h of release gas leave the melting reduction container with a dust load of 35 g / Nm3. In addition, 1,000 Nm3 / h of stirring gas, mainly nitrogen, are blown into the melt through the lower nozzles 3 to ensure the necessary movement of the melt bath and the accumulation of the foamed slag layer. In this operation with a foamed slag, a degree of post-combustion of 60% was achieved at a re-heat transfer of 85%, applying the method of the invention. In comparison, a 50% post-combustion was achieved with a heat re-transfer of 80% with the usual operation and the mixed addition of the reactive agents through the lower nozzles or solid no pearls or shot through of gaseous space. This results in a saving of 200 kg of carbon / ton of pig iron produced with the process of the invention over the usual operation. At the same time, productivity is increased from 8 to 10 tons / hour of pig iron. In the release gas, the amount of powder can be reduced by 25 g / Nm3 with the method of the invention, compared to the known operation. It is also significant that the content of carbon in the dust of the stripping gas of 15% with the usual operation can be reduced to 6% with the method according to the invention.This results in various advantages for post-treatment of the release gas, particularly in the gas cleaning plant, the method to increase the effectiveness of the reduction of smelting of oxidic metal carriers, particularly iron ore, and to improve the thermal efficiency of the fuels charged in the process of smelting reduction taking place in a reaction vessel containing a bath , - "" 'melted with a slag layer, and where the reaction gases escaping from the melted bath are post-burned with oxidizing gases, the resulting heat is transferred to the melted bath and the reactive agents, mineral and carbon, are fed to the melt from the top through the gaseous space of the reaction vessel, which is characterized in that these reactive agents, mineral and carbon, are added in a compact form to the molten bath as a composite material with or without additional escorting substances, can vary within broad limits without going beyond the scope of the invention. As long as the reactive agents, mineral and carbon, are added in a compact form to the molten bath as an agglomerate, it is within the scope of the invention, even if the composite material is added to a casting reduction vessel from different directions and heights, for example. The smelting reduction process itself can, of course, also be subject to considerable changes.

Claims (13)

1. CLAIMS 1. A method to increase the effectiveness of the reduction of smelting of oxidic metal carriers, particularly iron ore, and to improve the thermal efficiency of the fuels charged in the smelting reduction process that takes place in a reaction vessel that It contains a melted bath with a slag layer and where the reaction gases escaping from the melted bath are subjected to post-combustion with oxidizing gases, the resulting heat is transferred to the "molten" bath and the reactive agents, mineral and carbon, are fed to the melt at least partially from the top through the gaseous space of the reaction vessel, where these reactive agents, mineral and carbon, are added in a compact form to the molten bath as a composite material with or without additional escort substances. The method of claim 1, wherein the reactive agents are added to the melt in the form of perdigone s,
2. '"" * pearls, compact materials, or any other agglomerates, in homogeneous form or as mixtures of these composite materials.
3. 3. The method of claim 1, wherein green, cooked and sintered, pre-reduced composite materials, or mixtures of these agglomerates, are fed to the melt. The method of claim 1, wherein the content of carbon in the composite material is set to be at least high enough to be sufficient for the complete reduction of the metal oxide content in the composite material. The method of claim 1, wherein the fuel content in the composite material is set to be sufficiently high to be sufficient to cover the thermal balance of the smelting reduction process. The method of claim 1, wherein the reactive agent, carbon, is fed to the melt in the composite material in the form of carbon of various grades, coke, other solid carriers of carbon and hydrocarbons, as well as liquid hydrocarbons, such as oil of various qualities and boiling points, tar, bitumen, refinery waste. The method of claim 1, wherein the reactive, mineral agent is passed to the melt in the composite material as a granular and / or fine grained mineral, untreated or pre-reduced, with varying degrees of reduction or even as completely metallic material. The method of claim 1, wherein a pre-reduction is caused that goes as far as complete reduction in the composite material via the intimate contact of the reactive agents. The method of claim 1, wherein the composite or agglomerated materials are heated, ie pre-heated, in their dropping path in the casting reduction vessel before being submerged in the melt. The method of claim 1, wherein the composite material is added from a height of at least 0.2 m on the unprotected metal bath surface and / or at a speed of at least 1 m / s. The method of claim 1, wherein the agglomerates are adjusted in their weight-surface ratio with consideration to the material characteristics of the reactive agents so that the pre-heated composite materials still have a compact shape when they are submerged in. the melted The method of claim 1, wherein the agglomerates or composite materials have a maximum average temperature of 500 ° C when immersed in the melt. The method of claim 1, wherein the density of the agglomerates or composite materials is greater than the density of the foamed slag layer on the melted bath.