JPH09296209A - Production of molten metal with carbonaceous material packing layer type smelting reduction furnace - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce a low phosphorus pig iron by blowing powdery and granular ore kind containing iron oxide together with oxygencontaining hot blast into a carbonaceous material packing layer from tuyeres arranged in two steps at the upper and the lower parts in the carbonaceous material packing layer of a smelting reduction furnace. SOLUTION: The smelting reduction is executed to the iron oxide to produce the pig iron, by blowing the oxygen-containing hot blast into the carbonaceous material packing layer 19 formed in the smelting reduction furnace 1 from the tuyeres 4, 5 of the upper and lower two steps arranged at the lower part of the furnace barrel part, and also, blowing the powdery and granular ore kind containing the iron oxide from a main lance 14 arranged in the upper step tuyeres 4. In this case, slurry-like oil-containing metallic iron raw material is blown into the carbon-aceous material packing layer 19 from sub-lances 15 arranged in the upper step tuyeres 4 and/or the lower step tuyeres 5 to burn the oil content in the oil-containing metallic iron raw material, and thus, the phosphorus content in the raw material supplied in the furnace is vaporized to promote dephosphorization, thus the low phosphorus pig iron is efficiently produced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention has a packed bed of a carbon-based solid reducing agent formed in a smelting reduction furnace, and blows oxygen-containing hot air through a plurality of tuyere arranged at least in two stages below and below the furnace. Together with a selected tuyere that includes the tuyere located at the uppermost stage or the uppermost tuyere among the plurality of tuyere,
A method for producing a molten metal by blowing a powdery metal oxide raw material into the packed bed and subjecting the metal oxide raw material to smelt reduction to produce a molten metal, and particularly to produce a molten metal having a low phosphorus content by a smelting reduction furnace. That is the purpose.

[0002]

2. Description of the Related Art Generally, in order to produce a large amount of molten metal, for example, hot metal, a blast furnace that requires a lumpy raw material is often used. However, due to the recent circumstances of raw materials, the number of ores containing iron oxide or various metal oxides has decreased in the form of lumps and increased in the form of powders or small grains, which is considered to increase more and more. To be For this reason, usually, iron ore in the form of powder or granules is made into a lump-shaped sinter by a DL type sintering machine and then charged into a blast furnace. However, not only is it necessary to make a huge investment in equipment for a sintering machine that sinters powdered iron ore, but it also costs a great deal to maintain and manage the operation of the sintering machine. It is raising the cost of pig iron produced in the blast furnace.

Therefore, in the production of hot metal by a blast furnace,
In order to reduce costs, it is being studied to blow powdered ore from the tuyere, but as the amount of powdered ore blown increases, the blown ore adheres to the tip of the tuyere,
It is difficult to blow a large amount of powdery ores because it blocks the tuyere's blowing port, and it is not a fundamental solution.

On the other hand, in order to produce low phosphorus pig iron or low phosphorus steel,
Generally, low phosphorus coke is used during hot metal production in a blast furnace, dephosphorization is performed during hot metal pretreatment to reduce the blowing load of the converter, or dephosphorization is performed in the steelmaking process. It is being appreciated. Among these processes, in order to load low phosphorus coke into the blast furnace, for example, low phosphorus coke is produced by the conventional technique described in Japanese Patent Application Laid-Open No. 52-105920, and this is used in the blast furnace to dissolve phosphorus in the hot metal. Although it is possible to reduce the content, the coke produced by this method is expensive and disadvantageous from an economical point of view.

Further, dephosphorization in the hot metal pretreatment requires new pretreatment equipment, and has problems such as shortening the refractory life of the blast furnace tap pipe and the tope car. Preliminary treatment of hot metal and dephosphorization in the steelmaking process impose various burdens on converter blowing and external desulfurization in the next process, which is uneconomical when viewed as a total process of ironmaking or steelmaking. Furthermore, in order to aim at low phosphorus steel, there is a steelmaking technology called electrolysis, but the energy cost becomes enormous,
Not suitable for mass production.

Therefore, in recent years, as a method for inexpensively mass-producing low phosphorus pig iron having a phosphorus content of 0.05% by weight or less without using expensive carbon materials such as low phosphorus coke, Japanese Patent Laid-Open No. 57-198205.
In many publications such as Japanese Patent Laid-Open No. 58-77548 and Japanese Patent Laid-Open No. 58-77548, there is proposed a method for producing hot metal using a carbon material packed bed type smelting reduction furnace. As shown in FIG. 2, a carbonaceous material packed bed type smelting reduction furnace 1 is provided with an upper stage tuyeres 4 and a lower stage tuyeres 5, and a carbonaceous solid reducing material such as coke (carbonaceous material is supplied from a carbonaceous material supply device 6 above the furnace. ) Is supplied to form a carbonaceous material packed bed 19 in the furnace. Then, hot air is supplied from the high-temperature air blower 2, and the hot air is distributed by the high-temperature air blower distributor 3 to the tuyeres 4 and 5 in the upper and lower stages. The iron ore-containing powdery ores stored in the powdery ore supply device 7 and the powdery or granular flux stored in the flux supply device 8 are passed through the powdery or granular material blowing device 9 through the powdery or granular material transport pipe 10. , Is blown into the furnace together with a carrier gas such as air from a main lance 14 arranged in the upper tuyeres 4.

The powdery granular iron ore (iron oxide raw material) and the particulate granular flux blown from the main lance 14 into the furnace are heated by the hot air (high temperature air or oxygen-enriched high temperature air) blown into the upper stage. It melts in the space of the raceway 18 formed in front of the tuyere 4. This melt is the lower tuyere 5
It is reduced while it is dripped up and remains in the hearth as molten pig iron and slag. The slag is discharged from the slag spout 11 and the molten pig iron is discharged from the tap spout 12, respectively. At that time, the gas discharged from the top of the smelting reduction furnace 1 is processed by the exhaust gas processing device 13.

Since the entire carbonaceous material charged from the furnace top passes through a high temperature region of 1700 ° C. or higher, the applicant of the present invention has found that the carbonaceous material such as coke charged in the furnace has, for example, calcium phosphate Ca. Phosphorus existing as ₃ P ₂ O ₃ was considered to be dephosphorized by the chemical reaction explained by the following chemical reaction formulas (1), (2) and (3). (A) Phosphorus in coke is reduced by the following reaction in the hot raceway part.

Ca ₃ P ₂ O ₈ + 5C → 3CaO + 2P + 5CO (1) Further, the presence of SiO ₂ facilitates the reduction of the solid reducing agent from calcium phosphate by carbon C and gas CO. This is because when the reduction of phosphorus in the coke is performed in the region where the SiO ₂ concentration is high, the next chemical reaction proceeds. _{2Ca 3 P 2 O 8 + 3SiO} 2 + 10C → 3Ca 2 SiO 4 + 4P + 10C ···· (2) 2Ca 3 P 2 O 8 + 3SiO 2 + 10CO → 3Ca 2 SiO 4 + 4P + 10CO 2 ···· (3) the following reaction occurs, Dephosphorization is promoted.

Therefore, when the iron oxide raw material consisting of iron ore powder-containing ores (including sludge and dust) containing iron oxide is charged from the upper tuyeres, the SiO ₂ concentration in the iron oxide raw material is increased. , By increasing the SiO ₂ concentration in front of the upper tuyere and causing the reactions of the above chemical reaction formulas (2) and (3),
The dephosphorization reaction is accelerated. Then, the reduced phosphorus rises in the furnace together with the gas in the furnace, but as the temperature decreases, part of it adheres to dust and the like, and part of it becomes compounds such as PN, PS, PO, and PO _2. And the phosphorus concentration in the coke at the bottom of the raceway is reduced. (B) The phosphorus contained in the iron oxide raw material (ore) is
Since it is reduced by the following chemical reaction formula (4) in the vicinity of the raceway formed at the tuyere tip, the phosphorus concentration in the coke decreases at the lower portion of the raceway.

2Fe ₃ (PO ₄ ) ₂ + 16CO → 3Fe ₂ P + P + 16CO ₂ (4) That is, the iron oxide raw material blown from the tuyere melts at the raceway portion and the reaction of the chemical reaction formula (4) As a result, a part of phosphorus rises in the furnace, the melt is reduced while dripping between the cokes, and is moved to the lower part of the furnace to become pig iron. that time,
Since the phosphorus concentration in the coke is lowered by the reaction of the chemical reaction formula (1), the amount of phosphorus absorbed in the coke during the dropping is small, and the phosphorus concentration in the hot metal becomes low. When all the carbonaceous materials charged from the furnace top pass through the area of 1700 ° C or higher in the carbonized material packed bed, the temperature is sufficiently high in the raceway part where phosphorus and iron oxide coexist, so the gas phosphorus is promptly discharged. As the temperature rises in the furnace and the melt has a small viscosity and drops quickly, trapping of phosphorus into the hot metal hardly occurs.

The finer the particle size of the iron oxide raw material to be blown, the faster the heat transfer to the center of each particle, so that the temperature rises easily in a short time, and the reaction of the chemical reaction formula (4) is It is done more smoothly. Further, the higher the temperature is, the lower the viscosity is, and the coexistence time of phosphorus and hot metal is shortened, so that the phosphorus concentration in the hot metal is lowered. Further, the iron oxide blown into the raceway is melted and reduced by an endothermic reaction, so that it acts to lower the coke temperature.
Therefore, by using iron oxide having a small amount of impurities to be blown in to reduce the amount of heat that is wasted for raising the temperature of impurities, or by using iron oxide having a small endothermic amount, the reduction of the phosphorus concentration in the hot metal is promoted. It is also possible. The phosphorus dephosphorized from the iron oxide raw materials (ores) described in (B) above also adheres to dust etc. partly as the temperature decreases, and partly as P 2, N 2, PS, PO, PO ₂ It becomes a compound such as, and it escapes from the furnace top and is removed.

However, the smelting region in the carbonaceous material packed bed type smelting reduction furnace is mainly composed of the raceway space and the portion below which the molten material drips, and most of the reaction in this smelting region is an endothermic reaction. Is. To compensate for this heat,
It was necessary to burn the carbonaceous material at the lower tuyeres and compensate for it with the amount of blast heat. In addition, when a large amount of iron oxide raw material powder was blown from the tuyere in an attempt to increase the production amount in this furnace, a large endothermic reaction occurred in the raceway part, the temperature around the raceway became 1700 ° C or less, and the hot metal The phosphorus concentration in the inside increases. Therefore, it is necessary to burn a large amount of carbonaceous material for thermal compensation.

Further, when a large amount of carbonaceous material coke is burned in the lower tuyeres, the rate of descent of the carbonaceous material between the upper and lower tuyeres becomes faster, and the residence time between the upper and lower tuyeres becomes shorter, so that unreduced The melt is dripped as it is. In order to secure the residence time between the upper and lower tuyeres and proceed with the reduction, it was necessary to make the distance between the upper and lower tuyeres sufficiently long, and it was necessary to increase the furnace height in terms of equipment. In other words, in order to sufficiently vaporize the phosphorus in the coke in this carbonaceous material packed bed type smelting reduction furnace, the furnace cost must be high and the cost must be high and a large amount of expensive carbonaceous material must be used. There was a problem.

Therefore, the applicant of the present invention discloses, as a method for inexpensively mass-producing low phosphorus pig iron having a phosphorus content of 0.05% or less, by utilizing the characteristics of a carbon material packed bed type smelting reduction furnace. The methods disclosed in the official gazette and Japanese Patent Laid-Open No. 5-247549 have been proposed. This is because the carbonaceous material packed bed type smelting reduction furnace is different from the blast furnace, because a so-called softened fusion body is not formed in the furnace and phosphorus is not circulated in the furnace, which is preferable for the production of low phosphorus pig iron.
That is, as disclosed in the above publication, vaporization and dephosphorization can be performed by adjusting the temperature in the furnace to a high temperature. Thus, the carbonaceous material packed bed type smelting reduction furnace proposed by the present applicant not only solves the problem of exhaustion of future energy sources, but is also suitable for the production of pig iron having a low phosphorus content.

However, the smelting methods using the carbonaceous material packed bed type smelting reduction furnaces proposed so far still have problems from the viewpoint of low phosphorus pig iron production. That is, in the prior art disclosed in Japanese Patent Laid-Open No. 5-9527, the iron oxide raw material to be blown into the upper tuyeres needs to contain 20% or more of FeO, and is disclosed in Japanese Patent Laid-Open No. 5-247549. In the prior art, again, the iron oxide raw material blown from the tuyere requires a metal oxide in which vaporized phosphorus is aggregated. Such iron oxide raw materials are not common as metal oxide ores, and therefore, these smelting reduction treatment processes have a weak point that the selection range of iron oxide raw materials is narrow and can be used only in a limited case. there were.

When the specific iron oxide raw material as described above cannot be used, the phosphorus in the iron oxide raw material blown from the tuyere provided in the conventional smelting reduction furnace is vaporized in the high temperature raceway, but is oxidized. Since the iron raw material powder melts in a state where it is not sufficiently dispersed, smelting reduction proceeds inside the raceway. Therefore, the generated metal absorbs phosphorus gas, and as a result, it is difficult to produce a desired low phosphorus pig iron. As described above, the smelting methods using the carbonaceous material packed bed type smelting reduction furnaces that have been proposed so far still have problems from the viewpoint of low phosphorus content production.

[0018]

Oil-containing metal scraps, metal sludges, metal dusts, etc. contain Ni, Mo, etc., which are useful as metal raw materials, and are available at low cost. Therefore, its effective use was desired. However, when used by melting in an electric furnace, a converter, etc., there is a problem that the oil content vaporizes and clogs the exhaust gas system. Further, when the gas is transported to the tuyere of the blast furnace and is blown into the tuyere, the oil has a high viscosity, so that it adheres to the inside of the transfer pipe or the blow-in pipe to cause clogging, making it difficult to blow for a long time. On the other hand, if you try to blow it into a slurry, the pressure inside the furnace is high, so that the raw material powder adheres to the tip of the blowing tube, and this gradually grows to cause slugging, which also makes stable blowing impossible. However, it was not put to practical use. Therefore, at present, since the oil-containing metal scraps and the like are used after being degreased and washed in advance, the processing cost impairs the advantage of being an inexpensive metal raw material.

The carbonaceous material packed bed type smelting reduction furnace is a metal oxide raw material, for example, iron ore as an iron oxide raw material, as well as various kinds of iron mills such as sludge and dust generated during blowing of a converter. In addition to the advantage of using sludge or dust, oil-containing metal raw materials such as oil-containing metal scraps can be used. Furthermore, since relatively inexpensive weak coking coal or non-caking coal is used without using expensive electric power or strong coking coal, it is expected as a future hot metal manufacturing furnace where there is a concern that the energy cost will increase more and more. it can. The present invention has been made in view of the above circumstances and has a phosphorus content of 0.05% without using expensive carbonaceous materials such as low phosphorus coke.
Provided is a method for producing a molten metal by a carbon material packed bed type smelting reduction furnace capable of mass-producing inexpensively a molten metal having a low phosphorus content such as a low-phosphorous molten pig iron with a weight percentage of less than or equal to a raw material ore at a low cost. That is the purpose.

[0020]

[Means for Solving the Problems] In order to achieve the above object, the inventors of the present invention have conducted extensive studies and utilized the characteristics of a carbonaceous material packed bed type smelting reduction furnace, which is originally advantageous for dephosphorization, to obtain an oil content. This was made as a result of various experiments, paying attention to the use of fibrous or powdery metal scraps containing metal, metal-containing sludge, or metal-containing dust. That is, liquid fluid such as waste oil was added to the fibrous or powdery metal scrap or metal-containing sludge or metal-containing dust to be directly blown into the smelting reduction furnace in which the packed bed of carbon-based solid reducing material was formed. By using various slurry-like oil-containing metal raw materials and combining these alone or in an appropriate combination, it has succeeded in promoting vaporization and dephosphorization in the furnace, and completed the present invention.

That is, according to the present invention of claim 1, a carbon-based solid reducing agent packed layer is formed in the smelting reduction furnace, and oxygen is contained from a plurality of tuyere arranged at least in two stages below and below the furnace. While blowing hot air, using the main lance arranged at the tuyere located at the uppermost stage of the plurality of tuyere or at the selected tuyere including the uppermost stage tuyere, the metal oxide raw material in the form of powder is charged. In the method for producing molten metal by blowing into the layer, and melting and reducing the metal oxide raw material to produce molten metal, the position of the uppermost tuyere among the plurality of tuyere and A carbonaceous material packed bed type smelting reduction furnace characterized in that a slurry-like oil-containing metal raw material containing an oil component and a metal component is blown into the packed bed by using a sublance arranged below the uppermost tuyere. Molten metal by It is a manufacturing method.

According to the second aspect of the present invention, the slurry oil-containing metal raw material containing oil and metal is selected from oil-containing fibrous metal scrap, powder metal scrap, metal-containing sludge or metal-containing dust. The method for producing molten metal in a carbonized material packed bed type smelting reduction furnace according to claim 1, characterized in that the raw material is a slurry-like metal raw material obtained by adding a liquid fluid to one or more types.

[0023]

BEST MODE FOR CARRYING OUT THE INVENTION Conventionally, a packed bed of carbon-based solid reducing material (carbonaceous material) is formed, and at least two upper and lower stages for blowing hot oxygen-containing hot air (air or oxygen-enriched air) into the lower part of the furnace. Using a carbonaceous material packed bed type smelting reduction furnace having a plurality of tuyere provided, with oxygen-containing hot air from the tuyere, blown into the packed bed as iron oxide raw material granular iron ore containing iron oxide, The iron oxide in the iron oxide raw material was melt-reduced to produce hot metal. However, as mentioned above, in conventional operations,
Phosphorus in the iron oxide raw material blown from the tuyere is vaporized in the high temperature raceway, but most of the vaporized phosphorus is dissolved in the metal because there is metal produced by smelting reduction inside the raceway, The dephosphorization of the hot metal was insufficient.

Another source of phosphorus that migrates into the metal is phosphorus contained in the carbonaceous material, which is a reducing material. The phosphorus in the carbonaceous material is directly contacted with the metal or once with the ash content of the carbonaceous material. After being dissolved in slag, it is transferred to the metal by the reaction between slag and metal. After elucidating such a phosphorus transfer phenomenon, the present inventors have found that the following measures are effective for reducing the phosphorus content in the metal.

(1) The partial pressure of phosphorus vaporized inside the raceway is reduced. (2) Shorten the metal retention time in the raceway. (3) A metal having a low phosphorus content is supplied instead of the ore containing phosphorus. (4) Instead of the carbonaceous material containing phosphorus, a fuel or reducing agent with a low phosphorus content is used. (5) The amount of carbonaceous material containing phosphorus is reduced.

However, these measures have been comprehensively studied on the premise that the utilization of an inexpensive raw material, which is the greatest advantage of the smelting reduction by the carbon material packed bed type smelting reduction furnace, is not impaired. As a metal raw material containing, for example, a metal scrap containing oil and metal, sludge or dust, or a mixture of these with a liquid fluid such as waste oil or heavy oil to form a slurry is supplied to the carbonaceous material packed bed. Therefore, the above (1)-
It was found that all the measures of (5) could be satisfied.

Therefore, in the present invention, oxygen-containing hot air is blown from at least two upper and lower tuyeres as described above, and the tuyere or the uppermost tuyere of the plurality of tuyere is included. Using the main lance placed on the selected tuyere, the powdered granular metal oxide raw material, for example, powdered granular ore containing iron oxide (including sludge and dust containing iron oxide) is filled with carbonaceous material. A slurry containing an oil component and a metal component in the carbonaceous material packed bed by using a sublance at a position of the uppermost tuyere and / or a position lower than the uppermost tuyere among a plurality of tuyere. The oil-containing metal raw material is blown in.

[0028]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 shows a case where hot metal is produced as a molten metal using a carbonaceous material packed bed type smelting reduction furnace 1, and the structure of the furnace body itself is the same as the conventional case shown in FIG. The smelting reduction furnace 1 has the advantage of using coke produced from relatively inexpensive weak coking coal or non-caking coal without using expensive electric power or strong coking coal, so that the energy cost will be further increased. It is promising as an apparatus for manufacturing molten metal in the future, which is expected to rise.

As shown in FIG. 1, the smelting reduction furnace 1 is provided with an upper tuyeres 4 and lower tuyeres 5 at the lower part of the furnace belly, and a typical carbonaceous solid return material is supplied from a carbonaceous material supply device 6 above the furnace. A block of coke is supplied as a material, and descends in the furnace while forming a carbonaceous material packed layer 19 in the furnace. Further, oxygen-containing hot air (high-temperature air or high-temperature oxygen-enriched air) is supplied from the high-temperature air blower 2, and the hot air distributed by the high-temperature air blower distributor 3 is passed through the high-temperature air blower supply pipe 20 to the tuyere 4 at the upper and lower stages, 5 and are blown into the furnace from tuyeres 4 and 5, respectively. The hot air blown into the furnace from the upper tuyeres 4 and the lower tuyeres 5 in this manner forms the high-temperature raceway 18.

Powder and granular iron ore (iron oxide raw material) stored in the powder and granular ore supplying device 7 and the flux supplying device 8
The powdery and granular flux as a slag material that is stored in the main lance 14 arranged in the upper tuyere 4 passes from the powdery or granular material blowing device 9 through the powdery or granular material transport pipe 10 together with a carrier gas such as air. It is blown into the furnace. Main lance 14
The iron oxide raw material and the flux blown into the furnace from the
While melting in the space of the high temperature raceway 18 formed in front of the upper tuyeres 4, phosphorus in the iron oxide raw material is vaporized in the high temperature raceway.

On the other hand, the slurry-like oil-containing metallic iron raw material containing the oil and iron (metal iron) in the oil-containing metallic raw material supplying device 16 is operated by the oil-containing metallic raw material supplying device 16 to pass through the slurry transport pipe 17 to the upper tuyeres. 4 and / or lower tuyeres 5
Are blown into the furnace from the sublances 15 respectively arranged. The slurry-like oil-containing metallic iron raw material containing oil and iron needs to be a liquid fluid that can be transported by the slurry transport pipe 17, and the oil-containing metallic iron raw material originally has fluidity that can be transported by the slurry transport pipe 17. When it has, it can be used as it is. As the oil-containing metal scraps, there are used metal cutting scraps, metal machining scraps, and scrap dismantling scraps that are inexpensive and exist in large quantities in the market.

However, the fibrous metallic iron scrap, the powdery metallic iron scrap, the metallic iron-containing sludge, or the metallic iron-containing dust to which oil has adhered is normally transported by the slurry transport pipe 17 as it is, even if it contains oil. It is often not as liquid as possible. In such a case, by adding a combustible fluid (liquid) such as waste oil or heavy oil to the oil-containing metallic iron raw material, the slurry is adjusted to a slurry form with improved transportability to enable transportation by the slurry transport pipe 17. Will be used.
In this way, one type selected from fibrous metal iron scraps containing powdery oil and iron powder containing powdery metal iron scraps, metal iron-containing sludge or metal iron-containing dust, which is prepared by adding a combustible fluid such as waste oil to form a slurry, or Two or more oil-impregnated metallic iron raw materials are blown into the furnace from the sublance 15. It is also possible to arrange the sublance 15 between the upper tuyeres 4 and the lower tuyeres 5 and to supply the oil-impregnated metallic iron raw material from there. In short, it is important to blow the oil-impregnated metallic iron raw material into the position of the upper tuyeres 4 or the position below the upper tuyeres 4.

The iron oxide raw material and the flux blown into the furnace from the main lance 14 as described above are melted in the space of the high temperature raceway 18 formed in front of the upper tuyeres 4 and the iron oxide raw material is supplied. The phosphorus contained in the carbon and the phosphorus contained in the carbonaceous material as the reducing agent are vaporized in the high temperature raceway. In such a state, liquid components such as waste oil of the slurry-like oil-impregnated metallic iron raw material supplied into the furnace from the sublance 15 arranged in the upper tuyeres 4 expand in the raceway, and further in the furnace. Combustion of oil turns into combustion gas, increasing the gas volume. The phosphorus present in the gas in a vaporized state due to the rapid volume expansion is pushed deep into the inside of the furnace from inside the raceway 18 and rapidly rises in the furnace. For this reason,
The contact time between phosphorus and metal is shortened, and phosphorus can be suppressed from transferring to metal.

Further, since the rapid increase in the gas volume due to the combustion of oil causes a decrease in the phosphorus partial pressure in the gas phase, phosphorus is melted from the gas phase even when the gas phase and molten metal are in contact with each other. It also suppresses the transition to metal. Therefore, unlike the conventional case, the molten metal descends in the furnace without absorbing vaporized phosphorus, and the phosphorus concentration in the hot metal can be reduced. Further, among the liquid components supplied from the sublance 15 into the furnace, the combustion components such as waste oil act as a fuel and a reducing agent, so that the amount of carbonaceous material used can be reduced and the phosphorus derived from the carbonaceous material can be reduced. Can reduce the input amount of.

Of the substances supplied from the sublance 15 into the furnace, the metallic iron content is transferred to the metal as it is. However, if the metallic iron raw material having a low phosphorus content is selected, the phosphorus content of the metal can be reduced and the same amount can be obtained. Since the amount of iron oxide raw material used for producing hot metal can be reduced, the input of phosphorus derived from ore is reduced. Moreover, since metallic iron does not require reduction like ore, the carbonaceous material as a reducing agent can be reduced, which also reduces the phosphorus input amount due to the carbonaceous material.

In the present invention, as described above, metal sludge, metal dust and useful Ni, M containing oil that can be obtained at a low cost are used.
Oil-containing metal raw materials such as metal scraps containing o etc. can be effectively used together with oil. The oil component in the oil-containing metallic iron raw material supplied from the sublance 15 into the carbonaceous material packed bed 19 in the furnace is vaporized and decomposed in the high temperature area of 200 ° C or higher in the furnace, and the races of the upper and lower tuyeres 4 and 5 are decomposed. Even if there is an unburned portion burned in way 18, even if there is an unburned portion, the carbonaceous material packed layer 19 existing above the supply position
As a result, the problem of contaminating the exhaust gas system such as the exhaust gas treatment device 13 or causing clogging is eliminated.
Further, even if the slurry is supplied from the sublance 15 into the furnace, the internal pressure of the sublance 15 is not high unlike in the blast furnace, so that slugging does not occur at the tip of the sublance 15 and stable supply to the furnace is possible. To do.

As described above, it is advantageous to blow the iron oxide raw material powder into the tuyere 4 located at the uppermost stage among the tuyere 4 and 5 arranged in the upper and lower stages. This is because the iron oxide raw material powder blown together with the oxygen-containing hot air from the tuyere 4 located at the uppermost stage is melt-reduced in the raceway 18 at high temperature in the furnace, and vaporized phosphorus is immediately above the furnace. Because it rises to the outside, it is discharged outside the furnace without re-phosphorization. Then, the remaining iron oxide raw material is melted by the oxygen-containing hot air blown from the tuyere 5 arranged on the lower side while descending in the furnace, and the reduced raw gas generated by the combustion of the carbonaceous material and oil in the furnace. Reduction is accelerated. The amount of the slurry-like oil-containing metal raw material blown from the sublance 15 is determined in consideration of various operating conditions such as the furnace height, the number of tuyere (three or more stages are possible), and the metal oxide raw material.

Further, the sublance arranged in the lower tuyeres 5
The oil content of the slurry metallic iron raw material supplied from 15 not only reduces the consumption of carbonaceous material in the lower part of the furnace by burning, but the iron oxide in the descending iron oxide raw material is generated by the burning of the oil content. Is sufficiently reduced by the reducing gas. When only the coke charged into the furnace as carbon material is used, ash is accumulated in the furnace core after the coke burns, which is an obstacle to operation.However, since the combustion of oil does not generate ash, only the substitute part of the core is used. The ash accumulation on the ash will be mitigated, which will contribute to the stabilization of the furnace operation.

As described above, in the present invention, the upper and lower tuyere 4,
In addition to the oxygen-containing hot air from 5 and the iron oxide raw material from the main lance 14, the slurry oil-containing metal raw material was blown into the carbonaceous material packed bed from the sub lance 15, so that the front of the upper tuyeres 4 was caused by the combustion of oil. The vaporization and dephosphorization of the iron oxide raw material will be smoothly performed inside the formed raceway. Liquid oil such as waste oil and heavy oil can be used as the oil to be the auxiliary fuel, and the slurry-like oil-containing metal raw material can be transported by piping and can be burned in the raceway.

The embodiments of the present invention will be specifically described below. As shown in FIG. 1, a production test of chromium-containing pig iron was carried out using a carbonaceous material packed bed type smelting reduction furnace 1. The specifications of the smelting reduction furnace used in the test are as follows. Furnace inner diameter: 4 mφ Furnace height: 14 m Packed bed height: 11 m Packed coke particle diameter: 10-30 mm, average 15 mm Upper and lower tuyeres spacing: 2.5 m Tuyer diameter: 100 mm Number of tuyeres: 4 upper, 4 lower 8 tuyere diameter: 30mm Main lance: 4 arranged in upper tuyeres Sub lance: 4 arranged in upper tuyeres or 4 arranged in lower tuyeres, or 2 arranged in upper tuyeres, 2 arranged in lower tuyeres 2
Coke with an average particle size of 15 mm was charged from the furnace top into the smelting reduction furnace through the carbonaceous material feeder 6 to form a packed bed having a height of 11 m. Then, from the main lance arranged in the upper tuyeres 4, iron ore powder (average value C: 4.
7% by weight, T.Fe: 62.4% by weight, FeO: 31.8% by weight, Si
O _2: 0.8 wt%, T.Cr: 6.2 wt%, MnO: 4.0 wt%, Al
₂ O ₃ : 1.1 wt%, other oxides 20.6 wt%) 10t /
Slag material (flux) consisting of hr, CaO, and SiO ₂ is 1.7
t / hr was supplied. Grinding scraps (CGR) of a stainless steel coil having the chemical composition shown in Table 1 as an oil-containing metallic iron raw material, etching Ni sludge (powder), Ni-containing sludge (powder),
Using Ni catalyst A (powder) or Ni catalyst B (oil-containing powder), a waste oil having a chemical composition as shown in Table 2 was added as a transport medium to prepare a slurry to prepare an oil-containing metallic iron raw material. The oil-containing metallic iron-containing raw material thus slurried,
It was blown into the furnace from the sublance through the slurry transport pipe from the oil-containing metal raw material supply device.

[0041]

[Table 1]

[0042]

[Table 2]

At that time, the carrier gases used were oxygen-enriched air and high temperature air having a temperature of 800 ° C. produced by the high temperature air blower 2, and the high temperature air supply pipes 20 were used to connect the high temperature air supply pipes 20 to each other. Oxygen-enriched air (O ₂ : 41%) is supplied to the upper tuyeres 4, and air (O ₂ : 38%) is supplied to the lower tuyeres 5.
%) Was blown into the furnace, it was possible to operate smoothly.

The operating conditions are shown in Tables 3 and 4, and the operating results are shown in Table 5. In addition, in Tables 3, 4, and 5, a comparative example corresponding to the conventional method in which the slurry-like oil-impregnated metallic iron raw material was not blown, and a method for producing hot metal according to the present invention in which the slurry-like oil-impregnated metallic iron raw material was blown were used. The results are shown in comparison with the cases of Examples 1 to 11. Table 3 shows the amount of air blown from each of the upper and lower tuyeres, the blowing temperature, the oxygen gas concentration during blowing, and the amount of iron oxide raw material blown from the main lance arranged in the upper tuyeres. Indicates the type of oil-containing metallic iron raw material in the form of slurry blown from the sublance, the ratio of distribution to the upper and lower tuyere, the amount of metallic iron raw material blown in, and the amount of waste oil blown in.
As shown in Table 4, the proportion of the oil-impregnated metallic iron raw material blown into the upper tuyeres 4 and the lower tuyeres 5 is 50% in the upper and lower parts, 100% in the upper tuyeres 4, and the lower feathers. Mouth 5 has 3 levels for 100%. Furthermore, Table 5 shows the coke ratio, the slag ratio, the hot metal temperature, and the metal (hot metal) production amount as the operation results.

[0045]

[Table 3]

[0046]

[Table 4]

[0047]

[Table 5]

As is clear from Tables 3, 4, and 5, in Examples 1 to 11 of the present invention, the phosphorus concentration in the hot metal was generally lower than that in the comparative example by supplying the slurry-like oil-containing metallic iron raw material from the sublance. It shows that the dephosphorization of the hot metal was carried out smoothly. Further, it is clear that the coke ratio is also substantially reduced, the oil content plays a role in the substitution of fuel coke, and the production amount of metal shows an increasing trend.

The sublance position (m) from the upper tuyeres when waste oil was blown into the furnace as a flowing medium into stainless grinder scraps by changing the height position of the sublance arranged in the multiple parts of the smelting reduction furnace Figure 3 shows the relationship with the phosphorus concentration (%) in the hot metal, and the sublance position (m) from the upper tuyeres.
4 shows the relationship between the concentration of hydrocarbons in the exhaust gas from the furnace top (%). As is clear from FIG. 3, the phosphorus concentration in the hot metal can be lowered as the position of the sublance for supplying the slurry oil-containing metallic iron raw material is set below the upper tuyeres. When the sublance is arranged at the lower tuyere and the slurry-like oil-containing metallic iron raw material is supplied, the effect of lowering the phosphorus concentration in the hot metal is maximized. Further, it can be seen from FIG. 4 that the hydrocarbon concentration in the furnace top exhaust gas can be reduced by setting the position of the sublance for supplying the slurry oil-containing metallic iron raw material below the upper tuyeres.

[0050]

As described above, according to the present invention, an inexpensive oil-containing metal raw material, which has been difficult to process by using a carbonaceous material packed bed type smelting reduction furnace, can be used without pretreatment such as drying. It can be effectively treated with oil and has a social and environmental effect. By promoting vaporization and dephosphorization in the furnace, it becomes possible to inexpensively and easily mass-produce molten metal having a low phosphorus content. Further, since the metal of the oil-containing metal raw material does not require the heat of reduction, it becomes possible to mass-produce the molten metal without increasing the fuel cost.

The molten metal targeted by the present invention is not limited to the above-illustrated molten iron (that is, molten Fe-C alloys and those containing other elements such as Cr and Ni). The metal / alloy produced by melting and reducing by carbon reduction is not particularly limited. Combustible fuels such as the oil content of oil-containing metal raw materials and oil content used as a transportation medium can partially replace the carbonaceous material fuel, so not only can the carbonaceous material be saved, but the amount of impurities such as phosphorus contained in the carbonaceous material can be reduced. It is possible to suppress. Further, since the oil-containing metal raw material is transported in the form of slurry, abrasion of the transportation pipe can be reduced, and clogging of the exhaust gas system can be prevented by combustion of combustible fuel such as oil.

[Brief description of drawings]

FIG. 1 is a schematic vertical cross-sectional view showing a carbonaceous material packed bed type smelting reduction furnace for injecting a slurry oil-containing metallic iron raw material according to the present invention together with an auxiliary device.

FIG. 2 is a schematic vertical sectional view showing a conventional carbonaceous material packed bed type smelting reduction furnace.

FIG. 3 is a graph showing the relationship between the distance (m) from the upper tuyeres to the sublance position and the phosphorus concentration (%) in the hot metal.

FIG. 4 is a graph showing the relationship between the distance (m) from the upper tuyeres to the sublance position and the phosphorus concentration (%) in the furnace top exhaust gas.

[Explanation of symbols]

 1 Smelting reduction furnace 2 High temperature air blower 3 High temperature air blower distribution device 4 Upper stage tuyeres 5 Lower stage tuyeres 6 Carbon material supply device 7 Powder and granular ore supply device 8 Flux supply device 9 Powder and particle blowing device 10 Powder and particle transport pipe 11 Outlet port 12 Outlet port 13 Exhaust gas treatment device 14 Main lance 15 Sublance 16 Oil-containing metal raw material supply device 17 Slurry transport pipe 18 Raceway 19 Carbon material packed bed 20 High temperature air supply pipe

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yoshitaka Sawa 1 Kawasaki-cho, Chuo-ku, Chiba, Chiba Prefecture Inside the Technical Research Laboratory, Kawasaki Steel Co., Ltd. (72) Yoshiaki Hara 1 Kawasaki-cho, Chuo-ku, Chiba, Chiba Prefecture Kawasaki (72) Inventor Nozomi Nishimura, No. 1 Kawasaki-cho, Chuo-ku, Chiba-shi, Chiba Prefecture In Kawasaki Steel Co., Ltd. (72) Yasushi Nagata No. 1 Kawasaki-cho, Chuo-ku, Chiba-shi Kawasaki Chiba Steel Works, Ltd.

Claims (2)

[Claims] 1. A packed bed of a carbon-based solid reducing agent is formed in a smelting reduction furnace, and hot air containing oxygen is blown from a plurality of tuyere arranged at least in two stages at the lower part of the furnace, and the plurality of blades are provided. Using the main lance arranged at the tuyere located at the uppermost stage of the mouth or at the selected tuyere including the uppermost stage tuyere, a granular metal oxide raw material is blown into the packed bed to form the metal oxide. In a method for producing molten metal by a carbon material packed bed type smelting reduction furnace for producing molten metal by smelting reduction of a raw material, in the position of the uppermost tuyere and / or below the uppermost tuyere among the plurality of tuyere A method for producing molten metal by a carbonaceous material packed bed type smelting reduction furnace, characterized in that a slurry-like oil-containing metal raw material containing an oil component and a metal component is blown into the packed bed using a sublance arranged at a position. 2. The slurry-containing oil-containing metal raw material containing oil and metal is one or more selected from fibrous metal scraps containing powder, powdery metal scraps, metal-containing sludge or metal-containing dust. The method for producing molten metal by the carbon material packed bed type smelting reduction furnace according to claim 1, wherein the raw material is a slurry-like metal raw material to which a liquid fluid is added.