JP2007254812A - Method for producing sintered ore - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing a sintered ore by which the production yield of a sintered ore is increased and a material not recycled so far can be effectively utilized as a sintered ore material. <P>SOLUTION: In the method for producing a sintered ore with a Dwight-Lloyd sintered machine, a substance containing carbon in an amount of ≥1.0 t/m<SP>3</SP>is used as a caking material in sintering materials, so that formation of pores in a sintered ore is suppressed and the production yield of the sintered ore can be increased. By using carbon brick scraps not recycled so far by the reason that they are eroded by metal and slag and contain impurities as the above caking material, the method for producing a sintered ore can be achieved which allows not only increasing of the production yield of a sintered ore but also reduction of material cost and effective utilization of resources. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method for producing a sintered ore using a Dwytroid (hereinafter referred to as “DL”) type sintering machine, and a material having a large amount of carbon contained per unit volume is a coagulation material in a sintering raw material. It is related with the manufacturing method of the sintered ore which can improve a product yield by using as.

  In the general manufacturing process of sintered ore by the DL type sintering machine, the sintered ore is manufactured as follows. Sintered raw materials composed of fine iron ore, which is an iron source, coke as a coagulant, auxiliary raw materials for component adjustment, and return ore are mixed by a granulator and then supplied to a DL-type sintering machine. A raw material layer (hereinafter also referred to as “raw material bed”) is formed on the pallet. The DL type sintering machine includes a large number of pallets that circulate and the raw material layer is conveyed toward the ignition furnace as the pallet moves while being sucked downward by the blower.

  Immediately below the ignition furnace, the upper surface of the raw material layer is ignited and the coke in the raw material layer is combusted by the sucked air. In the region where the coke burns, a high-temperature combustion melting zone is formed. As described above, since air is sucked downward, the combustion melting zone proceeds downward, and a sintered ore is formed in the upper portion of the combustion melting zone. The lump of sintered ore on the pallet thus formed is also referred to as a sintered cake. Therefore, in the intermediate process of conveyance in the DL type sintering machine, a sintered cake, a combustion melting zone, and a raw material layer are mixed from above.

  The sintered cake fired in this manner is discharged from the waste ore section, then cooled, crushed and sized, and the sintered ore in a particle size range suitable for blast furnace use is sent to the blast furnace, and fine-grained firing that does not fall within the above range. The ore is again used as a raw material for sintering.

  In this way, the manufacturing process of the sintered ore by the DL type sintering machine is performed by burning the condensate by heat transfer from the gas passing from the upper part to the lower part through the packed bed of raw materials mixed with the condensate. It is characterized by advancing the reaction.

  Recently, the depletion of high-quality iron ore has progressed, and the use ratio of inferior iron ore with a small apparent density has also increased with respect to fine iron ore which is the main raw material of sintered ore. When the apparent density of the raw material used decreases, the macropores of the sintered ore that is the product increase, so that the sintered ore becomes brittle and the product yield deteriorates. For this reason, a new technique for improving the product yield is required.

  For example, Patent Document 1 discloses a method for producing a sintered ore that reduces the macropores of the sintered ore and improves the product yield and strength by applying downward pressure from the upper surface of the bed of the raw material during firing. Has been.

  However, the method disclosed in Patent Document 1 has a problem that its effect is limited to the vicinity of the surface of the sintered cake, and there is a problem that if excessive pressure is applied, the ventilation becomes poor and the productivity deteriorates. There is a limit.

  On the other hand, regarding refractories, various studies have been made on the recycling of used refractory waste from the viewpoint of effective utilization of resources and environmental protection. Carbon bricks used in blast furnaces and the like are flammable and cannot be disposed of in landfills. If they are not recycled, they can only be incinerated. For this reason, generally used carbon bricks are recycled as refractory raw materials.

  For example, Patent Document 2 discloses a castable that can be constructed with a small amount of water addition by specifying the water absorption rate, water absorption index, etc. of the material even when reused materials such as used bricks and irregular refractories are used. A method for kneading refractories is disclosed.

  However, carbon brick scraps used in blast furnaces and the like and eroded by metal and slag contain impurities, and there is a problem that the performance of the refractory deteriorates when recycled as a refractory raw material. For this reason, even if the method disclosed in Patent Document 2 is used, it is difficult to effectively use carbon brick scraps and the like.

JP-A-60-234927 JP 2004-59370 A (paragraph [0014])

  The present invention has been made in view of the above problems, and while improving the yield of sintered ore products, the used material is effectively used as a coagulant from the viewpoint of effective utilization of resources and environmental protection. It aims at providing the manufacturing method of the sintered ore which can be performed.

  Since the coagulant such as coke in the sintered raw material is burned off during the sintering process, the coagulant in the sintered raw material becomes pores in the sintered cake. When the pores in the sintered cake increase, the sintered ore becomes brittle, and the fine-grained ore, that is, the return ore increases, and the product yield decreases. When coke is used as the coagulant, the coke is about 4% in the mass ratio in the sintering raw material, but the apparent density is lower than that of iron ore. Become.

As described above, the present inventors have made various studies by paying attention to the fact that the influence of coke on the formation of pores is very large. As a result, new findings shown in the following (a) and (b) were obtained.
(A) A high-yield sintered ore can be obtained by using a substance having a large amount of carbon contained per unit volume as a coagulant in the sintered raw material. Specifically, by using a substance having a carbon content of 1.0 ton (t) or more per 1 m ³ , the generation of pores in the sintered ore is alleviated and the product yield of the sintered ore is improved. be able to.
(B) Examples of the material having a carbon content of 1.0 t or more per 1 m ³ include artificial graphite. However, artificial graphite is very expensive compared to coke, which increases the manufacturing cost. On the other hand, carbon brick scraps have a characteristic that the amount of carbon contained per unit volume is large, but carbon brick scraps eroded by metal and slag contain impurities, and thus have not been recycled conventionally. However, by using carbon brick scrap as a condensing material in the sintering raw material, not only the yield of sintered ore products is improved, but also a method for producing sintered ore that can reduce material costs and effectively use resources. Can be realized.

The present invention has been completed based on these findings, and the gist thereof is the following (1) to (3) manufacturing method of sintered ore.
(1) In a method for producing a sintered ore using a dweroid type sintering machine, a material having a carbon content of 1.0 t or more per 1 m ³ is used as a coagulant in a sintering raw material. A method for producing sintered ore.
(2) In a method for producing sintered ore using a Dwight-Lloyd type sintering machine, a mixture of a substance having a carbon content of 1.0 t or more per 1 m ³ and coke is a coagulation material in a sintering raw material. A method for producing a sintered ore characterized by being used as:
(3) In the method for producing a sintered ore according to the above (1) or (2), it is desirable to use carbon brick as the coagulant because the used material can be used effectively.

In the present invention, “the amount of carbon contained per 1 m ³ ” is the apparent density defined by JIS-Z 8901 (test powder and test particles) divided by the volume occupied by the mass of the powder. Value) is calculated by multiplying the carbon content by the carbon content, and means the mass of carbon contained per 1 m ^{3 of the} aggregate.

According to the method for producing a sintered ore of the present invention, in the method for producing a sintered ore using a DL type sintering machine, even if the iron ore that is the main raw material of the sintered ore is an inferior iron ore having a small apparent density, By using a substance with a carbon content of 1.0 t or more per 1 m ³ as a condensing material for sinter ore, the generation of pores in the sinter is alleviated and the product yield of the sinter is improved. Can be made.

In addition, even when a mixture of a substance having a carbon content of 1.0 t or more per 1 m ³ and coke is used as a coagulating material for a sintered ore raw material, the yield of the sintered ore product can be improved. As a result, even when a necessary amount of a substance having a carbon content of 1.0 t or more per 1 m ³ cannot be ensured, a stable sintered ore can be produced. Furthermore, by using carbon brick as the coagulant, carbon brick waste that has not been recycled conventionally can be used effectively.

As described above, the method for producing a sintered ore of the present invention is a method for producing a sintered ore using a DL type sintering machine, and sintering a substance having a carbon content of 1.0 t or more per 1 m ^3. It is characterized by being used as a condensing material in raw materials. Furthermore, it is desirable to use carbon brick as a condensing material. The reason why the present invention is defined in this way and the desirable range will be described below.

In the present invention, the reason why the amount of carbon contained per 1 m ³ is used more substances 1.0t as condensation material during sintering raw material, the carbon content contained per 1 m ³ is a material of less than 1.0t is This is because the difference in carbon amount from the coke used conventionally is small, and thus the effect of the present invention of relaxing the generation of pores in the sintered ore cannot be sufficiently exhibited. In order to exhibit the effect of the present invention more remarkably, it is desirable to use a substance having a carbon content of 1.4 t or more per 1 m ³ .

In addition, if the required amount of carbon contained per 1 m ³ used as a coagulation material for the sintering raw material cannot be secured, the substance with carbon content of 1.0 t or more and coke Can be used. In this case, the remarkable effect cannot be obtained as compared with the case where only the substance having a carbon content of 1.0 t or more per 1 m ³ is used as the coagulant. However, compared with the case where only coke is used as the coagulant, the effect of improving the product yield can be expected.

Furthermore, in the method for producing a sintered ore of the present invention, carbon brick waste that has been used in a blast furnace or the like can be used as a condensing material for the sintering raw material. The reason why carbon brick is selected as a coagulant is that the amount of carbon contained per 1 m ³ is 1.0 t or more. Thus, by using the used carbon brick scrap as a coagulant, it is possible to improve the yield of sintered ore products while reducing raw material costs.

  Further, the present invention aims to improve the yield of sintered ore products and to effectively use resources, so that the use of used carbon brick scrap as a condensing material for sintered raw materials is an object of the present invention. Match. In addition, about carbon brick, although utilization of the used carbon brick waste can be considered mainly, it cannot be overemphasized that it is applicable also with an unused brick.

  Next, an embodiment of the method for producing a sintered ore of the present invention will be described.

Since the product yield generally deteriorates due to rapid cooling of the upper layer portion of the sintered cake, when the production method of the present invention is used as a means for improving the product yield of the upper layer portion, the target sintering machine Depending on the method, the following method (1) or (2) can be applied.
(1) In the case of a sintering machine in which a fine raw material is charged in the upper layer part and a coarse raw material is charged in the lower layer part, the amount of carbon contained per 1 m ^{3 is} 1 as in the case of normal segregation charging. By refining a substance (condensation material) of 0.0 t or more, a coagulation material having a large amount of carbon contained per unit volume can be easily introduced into the upper layer portion, and the product yield of the upper layer portion can be improved.
(2) In the case of a sintering machine capable of intensively adding a coagulant to the upper layer part The sintering machine capable of intensively adding the coagulant to the upper layer part is, for example, a surge hopper for a sintering raw material Separately, it refers to a sintering machine that cuts out the condensing material from a cylindrical container installed across the width direction of the sintering pallet and adds the condensing material through multi-stage inclined chutes combined with slit-like or plate-like inclined chutes.

When using the above-mentioned sintering machine, the coagulant added to the upper layer part is a substance having a carbon content of 1.0 t or more per 1 m ³ , so that the upper layer is compared with the case where coke is used. The product yield of parts can be further improved.

  Thus, the manufacturing method of the sintered ore of this invention can select the application method suitable for the existing equipment structure, without requiring new equipment.

Example 1
In order to confirm the effect of the present invention, the following sinter production test was carried out to evaluate the quality and product yield of the product sinter.
[Test conditions]
Table 1 shows the amount of carbon contained per 1 m ^{3 of} the coagulated material used in this test, and Table 2 shows the standard operating conditions of the sintered raw material.

As shown in Table 1, the present invention example uses carbon brick scrap (T1) and artificial graphite (T2) whose carbon content per 1 m ³ is 1.0 t or more as a coagulant, and the comparative example is a standard. Coke (T3), which is a coagulation material, and active coke (T4) containing a small amount of carbon per unit volume were used as the coagulation material.

  In addition, as shown in Table 2, in both the present invention example and the comparative example, the conditions other than the aggregating material are all constant, and the amount of the aggregating material is equal to the amount of carbon contained in each of T1 to T4. Blended. A drum mixer (diameter: 600 mm, length: 1000 mm) was used as the granulator, and after adding water, the mixture was rotated for 4 minutes at a rotation speed of 30 rpm and mixed. The water content was adjusted to 7.5%.

The granulated sintered raw material was charged into a cylindrical sintering pot test apparatus and subjected to test firing. The size of the product sintered layer was 300 mm in diameter and 500 mm in layer height.
[Test Evaluation Items]
The test results were evaluated for reduced powdering property (RDI), reducible property (RI), cold strength (TI), and product yield.

  After the sintered cake of the sintered product is crushed by a crusher and dropped 4 times from a height of 2 m using an SI tester, a sintered ore with a particle size of 5 mm or more is made +5 mm product, and the floor is spread from the sintered cake. The product yield was defined as the mass ratio (%) of the +5 mm product to the mass excluding. Moreover, the -5 mm product was used as the return ore.

  The reduced powdering property was evaluated by an index RDI (−3 mm%) indicating the powdering rate after reduction, which was defined as the method of smelting division. This index means that the smaller the value, the better.

As the reducibility, the reduction rate RI (%) specified in JIS M 8713 is used, and as the cold strength, the rotational strength TI (+5 mm%) of the sintered ore specified in JIS M 8712 in the cold state is used. Using.
[Test results]
Table 3 shows sinter components and test results of tests T1 to T4.

As shown in Table 3, the examples of the present invention using a substance having a carbon content per 1 m ³ of 1.0 t or more as a coagulant improved the product yield. At this time, no clear change was observed with respect to reduced powdering property (RDI), reducible property (RI), and cold strength (TI).

FIG. 1 is a graph showing the relationship between the amount of carbon contained per 1 m ^{3 of the} aggregate in the sintered raw material and the yield of the sintered ore product.

From the results shown in Table 3 and FIG. 1, it was confirmed that the product yield was improved by using a substance having a carbon content per 1 m ³ of 1.0 t or more as a coagulant. Furthermore, even when carbon brick scrap that has not been recycled in the past is used as a coagulant, the product yield is improved as in the case where expensive artificial graphite is used as the coagulant.
(Example 2)
In order to confirm the effect of using a mixture of a substance with a carbon content of 1.0 t or more per 1 m ³ and coke as a coagulant, the following sinter ore production test was conducted and product sintering was performed. Ore quality and product yield were evaluated.
[Test conditions]
Table 4 shows the ratio of the agglomerated material and the particle size composition, and Table 5 shows the standard operating conditions of the sintered raw material.

As shown in Table 4, the carbon content contained per 1 m ³ in the present invention example and a carbon brick scrap and coke is more than 1.0 t 1: using mixtures were mixed in a ratio of 3 (T5) as a condensation material In the comparative example, coke (T6), which is a standard setting material, was used as the setting material.

Moreover, as shown in Table 5, in all of the present invention examples and the comparative examples, the conditions other than the aggregating material were all the same. The granulation method and the sintering tester used were the same as those in Example 1.
[Test results]
FIG. 2 shows sintered ore when coke is used alone as a coagulation material in a sintered raw material and when a mixture of a substance having a carbon content of 1.0 t or more per 1 m ³ and coke is used. It is a figure showing the product yield of.

From the results shown in FIG. 2, it is confirmed that the product yield improvement effect is exhibited by using as a coagulant a mixture of a substance having a carbon content of 1.0 t or more per 1 m ³ and coke. It was done. Furthermore, even when the proportion of the substance having a carbon content of 1.0 t or more contained per 1 m ³ in the coagulated material was 25%, a remarkable improvement effect of the product yield was obtained.

According to the method for producing a sintered ore of the present invention, in the method for producing a sintered ore using a DL type sintering machine, even if the iron ore that is the main raw material of the sintered ore is an inferior iron ore having a small apparent density, By using a substance with a carbon content of 1.0 t or more per 1 m ³ as a condensing material for sinter ore, the generation of pores in the sinter is alleviated and the product yield of the sinter is improved. Can be made.

In addition, even when a mixture of a substance having a carbon content of 1.0 t or more per 1 m ³ and coke is used as a coagulating material for a sintered ore raw material, the yield of the sintered ore product can be improved. As a result, even when a necessary amount of a substance having a carbon content of 1.0 t or more per 1 m ³ cannot be ensured, a stable sintered ore can be produced. Furthermore, by using carbon brick as the coagulant, carbon brick waste that has not been recycled conventionally can be used effectively.

  Thereby, it can be widely applied not only as a production method capable of improving the yield of sintered ore products but also as a production method of sintered ore which is excellent in economic efficiency and enables effective use of resources.

It is a figure showing the relationship between the amount of carbon contained per 1 m < ³ > of the aggregate in a sintering raw material, and the product yield of a sintered ore. The product yield of sintered ore when coke is used alone as the coagulation material in the sintering raw material and when a mixture of a substance having a carbon content of 1.0 t or more per 1 m ³ and coke is used. FIG.

Claims (3)

In a method for producing a sintered ore using a dwelloid-type sintering machine, a material having a carbon content of 1.0 t or more per 1 m ³ is used as a condensing material in a sintering raw material. Manufacturing method of ore. In a method for producing a sintered ore using a Dwytroid type sintering machine, a mixture of a substance having a carbon content of 1.0 t or more per 1 m ³ and coke is used as a coagulant in the sintering raw material. A method for producing a sintered ore that is characterized. The method for producing a sintered ore according to claim 1 or 2, wherein the substance used as the coagulant is carbon brick.

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