JP4984488B2 - Method for producing semi-reduced sintered ore - Google Patents

Description

  The present invention relates to a method for producing a semi-reduced sintered ore obtained by sintering raw materials such as iron ore, carbonaceous material, and auxiliary materials, and used as a blast furnace raw material.

Sinter ore, which is the main raw material of the blast furnace ironmaking method, is generally manufactured as follows. First, a CaO-based auxiliary material (also referred to as a lime-based auxiliary material) containing CaO such as limestone, quicklime, and dolomite in fine iron ore having an average particle size of 2.0 to 3.0 mm, which is about 8 mm or less, meteorite, containing SiO ₂ raw material such as nickel slag, generated in steelworks recovered powder recycled product, 3 to 5 mm smaller than sintered powder requiring particle size is small refiring, and coke powder, a carbonaceous material such as anthracite added, Further, an appropriate amount of water is added to adjust the humidity, and these are mixed and granulated to obtain pseudo particles having an average particle diameter of 3.0 to 5.0 mm. Next, the pseudo particles are filled to a height of about 400 to 600 mm on a pallet of an endless moving type sintering machine, the carbon material on the surface layer of the packed bed is ignited, and the carbon material is drawn while sucking air downward. It burns, and the pseudo-particles which are raw materials are sintered by the combustion heat at that time. The sintered cake obtained by sintering is crushed and sized to obtain a product sintered ore of 3 to 5 mm or more.

  Such sintered ore is charged into a blast furnace and gas-reduced mainly by CO to become pig iron.

Normally, the blast furnace ironmaking method mainly uses indirect reduction with CO gas, so it is restricted by gas reduction equilibrium, requires a large amount of reducing material, and is strong in terms of ensuring air permeability in the blast furnace. High quality high quality coke is required. In contrast, in recent years, from the viewpoint of global warming countermeasures by suppressing CO ₂ emissions and extending the life of coke ovens that are aging, direct iron oxide by carbon (hereinafter referred to as C) as a steelmaking process A process that mainly uses reduction has been developed and put into practical use. In this case, since there is no restriction on the gas reduction equilibrium, the basic unit of the reducing material can be reduced, and CO ₂ emission can be suppressed and the coke oven operating rate can be reduced.

  Examples of the method for producing reduced iron using direct reduction include a smelting reduction method, a rotary hearth method, and a rotary kiln method, all of which involve large-scale capital investment and extremely low productivity. For the reason, it is a supplementary process of the blast furnace method at present.

  On the other hand, a method has been proposed in which an existing sintering machine is used, and a reduction reaction is performed simultaneously with agglomeration on the sintering machine to produce a sintered ore partially including a structure reduced to metallic Fe. .

  For example, in Patent Document 1, 5 to 20 wt% of powdered coke and anthracite coal are granulated into an inner layer, and the outer layer is mixed with powdered ore, auxiliary materials, and 2 to 5 wt% of powdered coke and anthracite and coated 2 After forming layer pseudo-particles and mixing and granulating them as a part of the sintering raw material, sintering is performed by the direct reduction of the melt produced from the outer layer of the raw material and the inner layer of powdered coke and anthracite in the sintering process. A method for producing a semi-reduced sintered ore characterized by reducing a part of the ore is disclosed. In this technique, when powder coke and anthracite are confined in the interior, the powder coke and anthracite do not react with oxygen in the air in the first half of the temperature raising process in the sintering process, so they do not react and become FeO + C = only at a high temperature of 1100 ° C. A reduction reaction of Fe + CO-36350 kcal / kmol is caused to produce metallic Fe in a part of the sintered ore. Since this reaction is an endothermic reaction, it is possible to prevent heat from being excessive.

  According to Patent Document 2, CaO is coated on the surface layer of pseudo particles obtained by adding 15 to 18% of a carbonaceous material to iron ore or granulated, or the granulated pseudo particles are added to a solution in which CaO is dissolved. By dipping and adding CaO to the surface of the pseudo particles, re-oxidation after firing is prevented, and a semi-reduced sintered ore with a high reduction rate can be produced.

  In such an existing sintering machine, the method of adding semi-reduced sintered ore by using the direct reduction reaction to add carbonaceous materials necessary for the reduction to fine iron ore is a new large-scale capital investment. This is a highly feasible method for producing a semi-reduced sintered ore in large quantities without accompanying it. The semi-reduced sintered ore obtained with the existing sintering machine is used in a large amount in a blast furnace even if the ratio of metallic Fe contained in the sintered ore is low, and is used for reducing ore production. If the carbonaceous material to be contained contains C to some extent, there is almost no restriction on the quality, and dust collection dust etc. can be used, so the total effect such as reducing the blast furnace reducing material ratio and reducing the load on the coke oven is great. .

However, in the techniques shown in Patent Documents 1 and 2, it is necessary to burn about 2 to 4 times as much carbonaceous material as that of a normal sinter process, so even if the reduction reaction is an endothermic reaction, It tends to be excessive, and when it is reduced from Fe ₂ O ₃ or Fe ₃ O ₄ to FeO at high temperature, it reacts with gangue in the ore and added flux to generate a large amount of melt. . This melt is composed of a calcium ferrite melt generated by a reaction between a CaO-based auxiliary material added as an auxiliary material and ore, and an olivine-based melt generated by a reaction between FeO formed by reduction and gangue SiO ₂ in the ore. It is a liquid. The melt generated in a large amount in this way rapidly melts the surrounding particles, and at the same time, advances the melting from the outside to the inside of the pseudo particles. A huge void is formed in the sintering bed, which is the raw material packed layer, by melting and shrinking of the pseudo particles, and the suction gas in the sintering machine passes only through that portion. As a result, the sintering reaction in which the combustion zone should move gradually from the upper layer to the lower layer of the raw material packed layer, which is usually 400 to 600 mm, is hindered, and a large amount of unburned portion remains in the lower layer portion of the sintering bed. There is a problem that progress is prevented and productivity is extremely lowered.

For this reason, there is a problem in producing a sintered ore partially reduced in large quantities on a scale of several thousand tons per day as a main raw material of a blast furnace using an existing sintering machine.
JP-A-4-210432 JP 2000-192154 A

  The present invention has been made in view of such circumstances, and it is possible to stabilize the firing reaction without deteriorating the operation of the current sintering machine and to achieve a high reduction rate and a high metal iron content. It aims at providing the manufacturing method of a reduction sintered ore.

In order to solve the above-mentioned problems, the present invention uses iron ore, a carbon material, and a secondary material as a sintering raw material, and among the sintering raw material, a part of the iron ore and a part of the carbonaceous material, or among the sintering raw material Part of the iron ore, part of the carbonaceous material and part of the auxiliary material are pre-compressed into compression-molded particles, and the remainder of the sintered raw material is granulated, mixed and fired, In producing a semi-reduced sintered ore obtained by reducing a part of it with carbonaceous materials,
In the compression-molded particles , the thickness range of the thinnest part is 6 mm or more and 16 mm or less, the volume is 6 cm ³ or less, and the mixing ratio of the compression-molded particles is 40 to 70 mass% of the entire sintered raw material. The manufacturing method of the semi-reduction sintered ore characterized by these.

  In this invention, it is preferable that the quantity of the carbon material contained in the said compression molding particle | grain is 20 mass% or less. Moreover, it is preferable that the carbonaceous material contained in the said compression molding particle | grain is a particle size of 45-125 micrometers, and is 50-70 mass%. Furthermore, when the compression-molded particles are charged into the sintering machine, it is preferable to charge in the region of the raw material layer lower part 9/10 or less.

According to the present invention, iron ore and carbonaceous materials are molded into reduced iron production particles or compressed into compression-molded particles, and this is charged as part of the raw material layer. These contact areas become larger and the contact area becomes larger, and since the direct reduction reaction occurs only partially, a large amount of melt is not generated, and further, the oxidation of metal Fe is suppressed, and the metal Fe content is reduced. Can be increased. Further, in the compression molded particles , the thickness range of the thinnest part is set to 6 mm or more and 16 mm or less, and the volume thereof is set to 6 cm ³ or less, thereby suppressing excessive breathability by reducing the size of the compression molded particles. Since the mixing ratio of the compression-molded particles is allowed to be increased and the amount is set to a high value of 40 to 70 mass% of the entire sintered raw material, a very high reduction rate and metallization rate can be obtained. For this reason, it is possible to produce a large amount of semi-reduced sintered ore containing part of the iron ore by reducing the direct reduction without deteriorating the operation of the current sintering machine and reducing a part of the iron ore. . Therefore, by using this semi-reduced sintered ore in a blast furnace, it is possible to reduce the amount of reducing material used in the entire manufacturing process, and in turn reduce CO ₂ emissions from the manufacturing process.

Hereinafter, the present invention will be described in detail.
In the present invention, basically, iron ore, carbonaceous materials and auxiliary materials are used as sintering raw materials, and these are charged into a sintering machine to form a raw material layer, which is then fired to produce a semi-reduced sintered ore. To do.
At this time, a part of the iron ore and a part of the carbonaceous material among the sintered raw materials, or a part of the iron ore, a part of the carbonaceous material and a part of the auxiliary raw material among the sintered raw materials are compression-molded in advance. Mix the compression-molded particles with the compression-molded particles, the remainder of the sintered raw material as granulated material, and the thickness range of the thinnest part of the compression-molded particles between 6 mm and 16 mm and the volume of 6 cm ³ or less. The ratio is 40 to 70 mass% of the entire sintered raw material. Thereby, a part of iron ore is mainly reduced by direct reduction, and a semi-reduced sintered ore containing metal Fe is obtained.
Such a configuration is based on the following findings of the present inventors.
(1) The point for effectively advancing the direct reduction reaction of iron ore by C is the contact state between the carbon material that is the C source and the iron ore that is the substance to be reduced. And it is important that the contact area is large.
(2) Such molded particles contain a large amount of carbonaceous material for proceeding the reduction reaction and may be excessively melted. However, even if the portion is excessively melted, the molded particles are one of the sintering raw materials. Therefore, there is little risk of generating a large amount of melt, and the productivity of the sintered ore is hardly reduced without substantially affecting the ventilation of the entire sintered bed.
(3) Although the reduced particles may be re-oxidized by oxygen in the suction gas, the particles formed from iron ore and carbonaceous materials are in close contact with each other. Maintain the form, and even if the surface is oxidized, the inside is not easily oxidized, and a good reduced state is maintained.
(4) By reducing the thickness of the thinnest part in the compression molded particles from 6 mm to 16 mm and reducing the volume to 6 cm ³ or less, and reducing the compression molded particles from excessive ventilation. The mixing ratio of the compression-molded particles can be as high as 40 to 70 mass% of the entire sintered raw material.

Hereinafter, the present invention will be specifically described.
As in the blast furnace, the reduction reaction of iron ore is carried out by reaction with carbon in carbonaceous materials such as coke represented by formula (1) (direct reduction) and reaction with CO gas represented by formula (2) ( It proceeds by indirect reduction. The CO ₂ gas generated by the indirect reduction becomes CO gas by a reaction expressed by the equation (3) called a solution loss reaction.
Fe ₂ O ₃ + 3 / 2C = 2Fe + 3 / 2CO ₂ (1)
Fe ₂ O ₃ + 3CO = 2Fe + 3CO ₂ (2)
CO ₂ + C = 2CO (3)

  In these reduction reactions, indirect reduction is dominant when the temperature is 900 to 1100 ° C., and direct reduction is dominant when the temperature is 1200 ° C. or higher. In the present invention, when producing the semi-reduced sintered ore, the raw material layer temperature reaches about 1400 ° C., and the residence time of 1200 ° C. or more is lengthened to directly proceed the reduction.

  In this case, the compression-molded particles have a strong contact between the iron ore as the substance to be reduced and the carbonaceous material as the reducing agent, and the contact area is large. It can be effectively advanced. Moreover, since the particles for producing reduced iron are charged as a part of the raw material layer, the above reaction occurs locally, and only the portion of the particles for producing reduced iron is melted excessively, generating a large amount of melt. There is little fear. Furthermore, since the particles for producing reduced iron are in close contact with iron ore and carbonaceous material, and maintain their form after reduction, the internal reoxidation is prevented even by oxygen in the suction gas, which is good. The reduced state is maintained. For this reason, reduction can proceed directly without deteriorating the operation of the current sintering machine, a part of iron ore can be reduced, and a large amount of semi-reduced sintered ore containing metal Fe can be produced. it can.

Reduce the amount of reducing material used (reducing material ratio) as a whole of the ironmaking process by using semi-reduced sintered ore containing metal Fe in part of such iron ore in a blast furnace. As a result, CO ₂ emissions from the ironmaking process can also be reduced. In particular, the effect of reducing CO ₂ emission from the ironmaking process can be increased by preferentially precipitating metal Fe.

This point will be described in more detail.
FIG. 1 is a graph showing the relationship between the sinter ore reduction rate on the horizontal axis and the blast furnace reductant ratio on the vertical axis. The amount of pulverized coal injected is 131 kg / thm (131 kg per ton of hot metal). ). As shown in this figure, when the reduction rate of sintered ore increases, the reducing material ratio of the blast furnace decreases, and when the reduction rate exceeds 30%, the reduction rate becomes abrupt. Since the normal sintered ore has a reduction rate of about 2%, by obtaining a semi-reduced sintered ore having a reduction rate of 30% or more according to this embodiment, the reducing material ratio of the blast furnace can be greatly reduced. .

Although the reducing material ratio of the blast furnace can be lowered by increasing the reduction rate of the sinter in this way, as described above, from the viewpoint of more effectively reducing the CO ₂ emission amount, It is preferable to deposit metal Fe rather than to uniformly increase the reduction rate of the metal. This will be described with reference to FIG. In FIG. 2, the horizontal axis represents the average partial reduction rate of the sinter during blast furnace charging, and the vertical axis represents the amount of C discharged from the ironmaking process. It is a figure which compares and shows C discharge | emission amount with the sintered ore which generate | occur | produced preferentially. The line (a) is a case of a sintered ore that has been partially partially reduced uniformly, and the line (b) is a case of a sintered ore in which metal is preferentially generated. There will be between a) and line (b). In addition, "base" in a figure shows C discharge | emission amount when using the sintered ore which is not partially reduced. As is clear from this figure, it can be understood that the amount of C emission, that is, the amount of CO ₂ emission, can be further reduced by containing a larger amount of metal Fe than when the partial reduction is uniformly performed. In addition, in the case of semi-reduced sintered ore that has been partially partially reduced uniformly, the amount of C emission increases rather than the reduction rate up to 30%, and it seems that there is a similar tendency even if metal Fe is present to some extent. Therefore, it is understood that the reduction rate is preferably 30% or more in order to reduce the CO ₂ emission amount.

The amount of metallic Fe contained in the semi-reduced sintered ore is preferably 3 mass% or more as an overall average value. Thus, reducing reducing agent ratio in blast furnace, reduction and CO ₂ emissions in the entire ironmaking process, it is possible to effectively exhibit the effect of load reduction to coke oven.

  In the present invention, iron ore, carbonaceous material and auxiliary raw material are charged into a sintering machine as a sintering raw material and fired to produce a semi-reduced sintered ore obtained by reducing a part of iron ore with carbonaceous material. At this time, a part of the iron ore and a part of the carbonaceous material among the sintered raw materials, or a part of the iron ore, a part of the carbonaceous material and a part of the auxiliary raw material among the sintered raw materials are compressed and compressed in advance. Molded particles are formed, and the remainder of the sintering raw material is formed into a granulated product, which are mixed and fired.

  In this way, by compressing a part of the iron ore, a part of the carbonaceous material, and a part of the auxiliary raw material among the sintered raw materials, the iron ore and the carbonaceous material are consolidated to increase their contact area. Therefore, the reduction of the sintered ore can be promoted by charging such compression-molded particles into a sintering machine as a part of the raw material.

That is, compression-molded particles obtained by compression-molding a part of iron ore, a part of carbonaceous material and a part of auxiliary materials among the sintered raw materials are put into a sintering machine together with a granulated product of the sintered raw materials, and semi-reduction firing By producing the ore, a high reduction rate and a high metal Fe content are realized. By using such sintered ore in a blast furnace, the amount of reducing material used (reducing material ratio) in the entire manufacturing process can be further reduced, and as a result CO ₂ emissions from the manufacturing process can be further reduced. Can do.

  Here, the compression-molded particles are briquettes molded into a predetermined shape by a compression molding means in a roll molding machine, or are formed into a plate shape, a sheet shape, or a rod shape by a roll molding machine and then pulverized to a predetermined size. , Which means that the crushing strength of a single particle is 39.2 N or more.

  Such compression-molded compression-molded particles have a higher density than granulated products granulated with ordinary sintering raw materials, have a higher reduction rate when sintered than granulated products, and are sintered. The content rate of subsequent metal Fe becomes high.

  In the present invention, the iron ore is preferably a fine iron ore having a particle size of 8 mm or less from the viewpoint of maintaining good reactivity, and the carbonaceous material is a fine coke having a particle size of 5 mm or less, and further having a particle size of 3 mm or less. Powder coke is preferred. As the auxiliary material, CaO-based auxiliary materials such as limestone and quicklime are used.

In the present invention, from the viewpoint of obtaining optimum air permeability and reactivity, in the compression molded particles , the thickness range of the thinnest portion is 6 mm or more and 16 mm or less, and the volume of the compression molded particles is 6 cm ³ or less. To do. Thereby, the air permeability can be appropriately controlled, and the air permeability is prevented from becoming excessive even if the ratio of the compression molded particles is increased. For this reason, the mixing ratio of the compression molded particles can be increased.

  For this reason, in the present invention, the mixing ratio of the compression-molded particles can be set as high as 40 to 70 mass% of the entire sintered raw material, and the high reduction rate and high metal rate of iron ore can be significantly promoted. .

  In the present invention, the compression-molded particles preferably have a carbonaceous material content of 20 mass% or less. By setting the upper limit, the firing can be further stabilized. Here, if the amount of the carbonaceous material contained in the compression-molded particles is 20 mass% or less, the iron ore of the granulated product can be effectively reduced within this range, and unreacted coke is produced. It is because it is hard to remain.

  It is preferable that the carbonaceous material contained in the compression-molded particles has a particle diameter of 45 μm or more and 125 μm or less to be 50 to 70 mass%. By refining the carbonaceous material in this way, the reactivity of the reduction reaction with the iron ore is increased, and the reduction rate of the iron ore can be further increased.

  As the granulated material used as the remainder of the sintered raw material, a material formed by rolling and granulating a sintered raw material mainly composed of iron ore, carbonaceous material and CaO-based auxiliary raw material with a drum mixer, a disk pelletizer or the like is used. . In this case, ordinary iron ore is used as the iron ore, powder coke is used as the carbon material, and limestone or quick lime is used as the CaO-based auxiliary material. The blending ratio is preferably 2 to 6 mass% in terms of the number of carbonaceous materials when the iron ore and CaO-based auxiliary material is 100 mass%. The CaO-based auxiliary material is preferably about 4 to 10 mass% in the total amount of the iron ore and the CaO-based auxiliary material.

  As the sintering machine, it is preferable to use a downward suction type endless moving type sintering machine. Specifically, an ignition furnace provided on the moving path of the moving grate by supplying a granulated product and a compression-molded particle obtained by granulating the sintered raw material onto the endless moving type moving grate to form a raw material layer. Thus, the raw material layer is ignited and sintered. A plurality of wind boxes are arranged immediately below the moving grate, and the gas above the raw material layer is sucked downward through each wind box during sintering.

  The sintering raw material may be charged into the sintering machine after mixing the compression-molded particles and the granulated material, or mixed when forming both raw materials separately to form the raw material layer. May be.

  When the compression-molded particles are charged into the sintering machine, it is preferable to charge in the region below 9/10 of the raw material layer of the sintering machine. In the region close to the surface of the raw material layer, the temperature during sintering is relatively low and the high temperature holding time is short. Further, since the air permeability is increased by inserting the compression-molded particles into a region close to the surface of the raw material layer, this tendency becomes more remarkable. As a result, the reduction reaction of the compression-molded particles ends in an insufficient state as compared with the lower layer of the packed bed.

Next, a specific example of the method for producing the semi-reduced sintered ore according to the present embodiment will be described.
FIG. 3 is a schematic diagram showing an example of equipment for producing the semi-reduced sintered ore according to the present embodiment. This facility includes a molded particle manufacturing facility 100, a granulated material manufacturing facility 200, and a downward suction type endless moving sintering machine 300.

  The molded particle manufacturing facility 100 includes a raw material hopper group 101 that can supply iron ore, a solvent, a reducing agent, a binder, and the like, a mixer 102 that mixes the raw material and a binder (for example, starch, tar, molasses), and a mixture. A compression molding machine 103 for obtaining compression molded particles, the raw material from the raw material hopper group 101 is conveyed to the mixer 102, and the mixture mixed in the mixer 102 is conveyed to the compression molding machine 103, and compression molding is performed. The compression-molded particles produced by the machine 103 are conveyed to the granulator 202.

  The granulated product manufacturing facility 200 includes a raw material hopper group 201 capable of supplying an iron ore mixture, a solid fuel, a medium solvent, and the like, and a granulator 202 for mixing these and granulating the raw material. The raw material from the hopper group 201 is mixed and conditioned and conveyed to the granulator 202, and the granulated product produced by the granulator 202 and the compression molded particles produced by the compression molding machine 103 are granulated. It is mixed in 202 and conveyed to the sintering machine 300.

  The downward suction type endless moving type sintering machine 300 has an endless moving type moving grate 301, and a mixture of granulated material and compression-molded particles is supplied onto the moving grate 301 by an appropriate charging system. Thus, the raw material layer 303 is formed.

  An ignition furnace 302 is provided in the movement path of the moving great 301, and when the granulated material on the moving great 301 passes through the ignition furnace 302, it is ignited and sintering of the raw material layer 303 is started. A cake 303a is formed. A crusher (not shown) is provided on the exit side of the moving grate 301, and the sintered ore dropped from the moving grate 301 is crushed by this crusher, supplied to the conveyor 304, and supplied to the blast furnace.

  A plurality of wind boxes 305 are arranged immediately below the moving grate 301 along the traveling direction of the moving grate 301, and a vertical duct 306 is connected to each wind box 305. Thereby, the gas above the raw material layer 303 is sucked through the raw material layer 303 by the wind box 305 and the vertical duct 306.

  The vertical duct 306 is connected to a main exhaust gas duct 307 arranged horizontally, and gas is discharged through the main exhaust gas duct 307. An electric dust collector 308 and a main blower 309 are connected to the main exhaust gas duct 307, and the gas above the material layer 303 is sucked by the main blower 309, and the wind box 305, the vertical duct 306, the main exhaust gas duct 307, the electric dust collector. It is discharged from the chimney 310 via 308 and the like.

  Note that a gas supply hood may be provided in the downstream portion of the ignition furnace 302 above the raw material layer 303, and an exhaust gas circulation duct connected to the hood from the vertical duct 306 may be provided to perform exhaust gas circulation. By adopting such an exhaust gas circulation system, it becomes easy to appropriately control the atmosphere (oxygen concentration) in the raw material layer 303, which is more effective for the generation of metal Fe and the prevention of reoxidation.

  In the equipment configured as described above, the compression-molded particles are produced by the shaped particle production equipment 100, the granulated product is produced by the granulated product production equipment 200, and this is mixed by an appropriate means. The raw material layer 303 is formed by supplying on the moving grate 301 of the suction type endless moving type sintering machine 300. At this time, the raw material layer 303 is in a state where the compression-molded particles are dispersed in the matrix of the granulated product.

  Then, the surface of the raw material layer 303 is ignited by the ignition furnace 302 and fired while sucking the gas downward through the wind box 305 to sinter the granulated material constituting the raw material layer 303 to obtain a sintered ore. . The sintered ore obtained by sintering in this manner falls from the moving great 301, and the sintered ore dropped by the crusher on the outlet side is crushed and supplied to the conveyor 304, and further supplied to the blast furnace. . In this case, as described above, in the compression-molded particles of the raw material layer 303, direct reduction occurs between the iron ore and the carbonaceous material, and the iron ore is partially reduced and partially reduced to a metal Fe. The ore is produced.

  In addition, the sintering raw material may be charged into the sintering machine 300 by separately charging the compression-molded particles and the granulated material and mixing them when forming the raw material layer 303. In order to charge in this way, for example, as shown in FIG. 4, the granulated material 401 is supplied from above by a conveying means, for example, a belt conveyor 409, and at the appropriate position of the raw material layer 402 for compression molding particles. The compression-molded particles 404 may be supplied from the hopper 407 through a chute 403 whose charging position can be adjusted. Reference numeral 405 is a floor covering, 406 is a sintered pallet, 408 is a quantitative cutting device for compression-molded particles, and 410 is a segregation charging device. By adopting such an apparatus configuration, the distribution of the compression-molded particles can be arbitrarily changed. For example, as described above, the material can be charged in the area below the raw material layer 9/10 of the sintering machine. It becomes.

Examples of the present invention will be described below in comparison with comparative examples.
Here, the iron ore mixture, fine ore, limestone, quicklime and powder coke as the sintering raw materials having chemical components shown in Table 1 were used. Using these sintered raw materials, granulated particles were prepared according to the formulation shown in Table 2, and compression molded particles were prepared according to the formulation shown in Table 3. As the size of the compression-molded particles, those A to D shown in Table 4 were used.

Using these granulated products and compression molded particles, compression molding particles and their addition ratios were adjusted as shown in Comparative Examples 1 to 3 and Examples 1 to 12 in Table 5, and a sintering pot test was performed. Comparative Examples 1 to 3 are conditions outside the scope of the present invention, and Examples 1 to 12 are conditions within the scope of the present invention. In the sintering pot test, the raw material was pretreated under the same mixing and granulation conditions, and the raw material packed layer was 270 mm in diameter × 300 mm in height, and the suction negative pressure was 6 kPa. The test results are also shown in Table 5.
In any of Comparative Examples 1 to 3 and Examples 1 to 12, the granulated material was coated with 3 mass% of powdered coke as a raw material as a coagulant.

Of Table 5, Comparative Example 1 shows that the coke content in the compression molded particles is 12.5 mass%, the ratio of the coke particle size of 45 to 125 μm contained in the compression molded particles is 40 mass%, and the size of the compression molded particles is as shown in Table 4. As shown in A, the dimensions are 36 mm × 26 mm × 20 mm, the volume is out of the range of 10 cm ³ from the present invention, and ³⁰ mass% lower than the range of the present invention is added as a raw material charged with the compression molding to fill the sintered raw material. This is a case where the entire layer is charged and fired. Firing was carried out satisfactorily, and the reduction rate of the compression molded particles was 48%.

Comparative Example 2 is a case where the amount of compression-molded particles is increased and 40 mass% is added to Comparative Example 1. Although the production rate is increased compared to 1.20T ^/ m 2 ^/ hr in Comparative Example 1 at 1.26T ^/ m 2 ^/ hr, the reduction rate was 35%, the compression molding particles compared with 48% of Comparative Example 1 The reduction rate decreased significantly with the increase in the amount added.

  Comparative Example 3 is a case where the amount of compression-molded particles added is further increased with respect to Comparative Example 2 and 70 mass% is added. The production rate increased compared to Comparative Example 1, but the reduction rate was 18%, which was significantly lower than the 48% of Comparative Example 1 due to an increase in the amount of compression molded particles added. Compared to Comparative Example 2, the reduction rate further decreased.

  Example 1 is a case where the size of the compression-molded particles is reduced to B in Table 4 with respect to Comparative Example 2. The production rate was slightly lower than that of Comparative Example 2, but higher than that of Comparative Example 1. The reduction rate was 55%, which was significantly improved as compared with 48% in Comparative Example 1 and 35% in Comparative Example 2.

  Example 2 is a case where the size of the compression-molded particles is reduced to B in Table 4 with respect to Comparative Example 3. The production rate was slightly lower than that of Comparative Example 3, but higher than that of Comparative Example 1. The reduction rate was 46%, which was lower than 48% in Comparative Example 1 but significantly improved from 18% in Comparative Example 3.

  Example 3 is a case in which the size of the compression-molded particles is further reduced to C in Table 4 with respect to Example 1. The production rate was almost the same as that in Example 1, but the reduction rate was 58%, which was further improved from 55% in Example 1.

  Example 4 is a case where the size of the compression-molded particles is further reduced to C in Table 4 with respect to Example 2. The production rate was almost the same as that of Example 2, but the reduction rate was 48%, which was improved from 46% of Example 2.

  Example 5 is a case where the size of the compression molded particles is further reduced to D in Table 4 with respect to Example 1 and Example 3. The production rate decreased compared to Example 1 and Example 3, but the reduction rate was 60%, which was improved compared to 55% in Example 1 and 58% in Example 3. In addition, baking was also performed satisfactorily.

  Example 6 is a case where the size of the compression-molded particles is further reduced to D in Table 4 with respect to Example 2 and Example 4. Although the production rate decreased compared to Example 2 and Example 4, the reduction rate was 54%, which was improved compared to 46% in Example 2 and 48% in Example 4. In addition, baking was also performed satisfactorily.

  Example 7 is a case where the content of coke in the compression-molded particles is increased to 20.0 mass% with respect to Example 1. The production rate was almost the same as that in Example 1, and the reduction rate was 54%, which was almost the same as 55% in Example 1. In addition, baking was also performed satisfactorily.

  Example 8 is a case where the content of coke in the compression-molded particles is increased to 20.0 mass% with respect to Example 2. The production rate was almost the same as in Example 2, and the reduction rate was 47%, which was almost the same as 46% in Example 2. In addition, baking was also performed satisfactorily.

  Example 9 is a case where the proportion of coke in the compression-molded particles in the compression-molded particles is increased from 45 to 125 μm to 50 mass% with respect to Example 1. Although the production rate is lower than that of Example 1, the reduction rate is 59%, which is an improvement over 55% of Example 1. In addition, baking was also performed satisfactorily.

  Example 10 is a case where the proportion of coke in the compression-molded particles in the compression-molded particles is significantly increased to 70 mass% with respect to Example 2. Although the production rate is lower than that of Example 2, the reduction rate is 55%, which is a significant improvement compared to 46% of Example 2. In addition, baking was also performed satisfactorily.

  Example 11 is a case where the compression-molded particles are charged into the region below 9/10 of the raw material layer in the sintering machine raw material packed layer and fired as compared with Example 1. The production rate was improved as compared with Example 1, and the reduction rate was 58%, which was improved as compared with 55% of Example 1. In addition, baking was also performed satisfactorily.

  Example 12 is a case where the compression-molded particles are charged into the region below 9/10 of the raw material layer in the sintering machine raw material packed layer and fired as compared with Example 2. The production rate was improved as compared with Example 2, and the reduction rate was 49%, which was improved compared with 46% of Example 2. In addition, baking was also performed satisfactorily.

The figure which shows the relationship between the reduction rate of a sintered ore, and a blast furnace reducing material ratio. Comparison of the relationship between the average partial reduction rate of sinter during blast furnace charging and the amount of C discharged from the ironmaking process between the sinter with uniform partial reduction and the sinter with the preferential generation of metallic Fe FIG. The schematic diagram which shows an example of the equipment for enforcing the manufacturing method of the semi-reduction sintered ore which concerns on embodiment of this invention. The figure for demonstrating an example of the charging method of the sintering raw material in the manufacturing method of the semi-reduction sintered ore which concerns on embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Molded particle manufacturing equipment 200 Granulated product manufacturing equipment 300 Downward suction type endless moving type sintering machine 401 Granulated product 402 Raw material layer 403 Chute 404 Compression molding particle 405 Floor covering 406 Sintering pallet 407 Compression molding particle hopper 408 Compression Quantitative cutting device for molded particles 409 Belt conveyor

Claims (4)

Using iron ore, carbonaceous material, and auxiliary raw materials as sintering raw materials, part of iron ore and part of carbonaceous material among sintered raw materials, part of iron ore, part of carbonaceous material among sintered raw materials And a part of the auxiliary raw material is compression-molded in advance to form compression-molded particles, the remainder of the sintered raw material is granulated, mixed and fired, and a part of iron ore is reduced with carbonaceous material. In producing reduced sintered ore,
In the compression-molded particles , the thickness range of the thinnest part is 6 mm or more and 16 mm or less, the volume is 6 cm ³ or less, and the mixing ratio of the compression-molded particles is 40 to 70 mass% of the entire sintered raw material. A method for producing a semi-reduced sintered ore characterized by the above.   The method for producing a semi-reduced sintered ore according to claim 1, wherein the amount of the carbonaceous material contained in the compression-molded particles is 20 mass% or less.   3. The semi-reduced sintered ore according to claim 1, wherein a carbonaceous material contained in the compression-molded particles has a particle diameter of 45 to 125 μm and is 50 to 70 mass%. Manufacturing method.   The semi-reduction sintering according to any one of claims 1 to 3, wherein when the compression-molded particles are charged into a sintering machine, the particles are charged into a region below 9/10 of the raw material layer. Production method of ore.

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