JP6021714B2 - Method for producing sintered ore for iron making - Google Patents

Description

  The present invention relates to a method for producing a sintered ore for iron making.

Conventionally, not only iron ore mined but also sintered ore obtained by firing powder ore has been used as a blast furnace raw material. Various techniques for producing such sintered ore have been developed as shown in the following patent documents.
In Patent Document 1, in a method for producing a sintered ore by sintering a sintered raw material containing various ores and auxiliary materials, 50% or more of the ore to be mixed with the sintered raw material is pisolite ore, and other ores Ore containing 2% or more and less than 5% of SiO ₂ and 3% or more and less than 6% of bound water, and pellet feed or ore containing SiO ₂ of less than 2%.

In Patent Document 2, in a sintered ore production method in which 30 to 50% of iron ore raw material is pisolite ore, 70 to 80% of the whole pisolite ore, iron ore raw material excluding pisolite ore, limestone, serpentine and coke are used. The remaining 20-30% of pisolite ore is mixed and charged into a sintering machine for sintering.
Patent Document 1 discloses a composition (Fe ₂ O ₃ .2H ₂ O) as a goethite, but the composition of the goethite is Fe ₂ O ₃ .H ₂ O, which seems to be erroneous.

  In addition to Patent Literature 1 and Patent Literature 2, there are methods shown in Patent Literatures 3 to 7 as methods for producing sintered ore. Although not in the steel field, Patent Documents 8 and 9 disclose techniques for producing color pigments used in cosmetics and paints using iron hydroxide as a raw material.

Japanese Patent Laid-Open No. 10-245638 Japanese Patent Laid-Open No. 08-176688 JP 05-098359 A JP 05-105969 A Japanese Patent Laid-Open No. 04-080327 JP 2007-169707 A Japanese Patent Laid-Open No. 08-027525 JP 2005-255500 A Japanese Patent Laid-Open No. 10-204318

Patent Documents 1 and 2 are techniques for producing sintered ore using a raw material having a valence n of 1.0 or less when iron hydroxide is represented by Fe ₂ O ₃ .nH ₂ O. That is, as shown in the techniques of Patent Documents 1 and 2, in the field of producing sintered ore, the idea of producing sintered ore using iron hydroxide having a valence n exceeding 1.0 is There was nothing at all. In addition, even if other patent documents 3-7 are seen, there is no technique which manufactures a sintered ore using the iron hydroxide whose valence n exceeds 1.0 similarly. Although techniques for using iron hydroxide having a valence n exceeding 1.0 are disclosed in Patent Documents 8 and 9, these techniques are completely different from the techniques for producing sintered ore for iron making. Is.

  The present invention has been made in view of the above-mentioned problems, and is an inferior iron ore (iron hydroxide with a valence n exceeding 1.0, in other words, an ultrahigh crystal water-containing ore that could not be used conventionally. It is an object of the present invention to provide a method for producing a sintered ore for iron making that can be used as a raw material for iron making such as a blast furnace.

In order to achieve the above-described object, the present invention takes the following technical means. In the method for producing a sintered ore for iron making according to the present invention, n of Fe ₂ O ₃ · nH ₂ O exceeds 1.0 and is not more than 4.0, and a CaO source is made of CaO / Fe ₂ O ₃ . A first mixture is produced by mixing so that the molar ratio is more than 0.5 and less than 2.0, and a second mixture is produced by mixing powder coke having a particle size of 1000 μm or less with the first mixture. the second mass ratio of the powder coke to a mixture and 2-20%, wherein the first mixture with less than 30 wt% or more 2% by weight relative to the other sintering material, the said second mixture by sintering and other sintering material, characterized by producing a sintered ore.

Good Mashiku is for the to charged and the other sintering material the granulated product after having been granulated said second mixture and granules, relates size of the granulated product, 1 mm or less Is 10% by mass or less, and 10 mm or more is preferably 10% by mass or less.

Preferably, when the second mixture is granulated into a granulated product, the CaO source is quick lime, and the SWR represented by “mass of granulated water ÷ mass of quick lime” is 0.3 or more and 0. .8 or less.
Preferably, when the granules by granulating the second mixture may have use of a high speed stirring mixer.

  According to the present invention, inferior iron ore (iron hydroxide with a valence n exceeding 1.0, in other words, ultra-high crystal water-containing ore) that could not be used conventionally is used as a raw material for iron making such as a blast furnace. can do.

It is a figure which shows a heat pattern when performing sintering. It is a figure which shows a mixture. It is a relationship figure of n of iron hydroxide when a production rate is 2.3-2.5 (t / m < ² > / h), and a yield. It is a related figure of n of iron hydroxide when a production rate is 1.7-1.9 (t / m < ² > / h), and a yield. It is a _CaO-Fe 2 _{O 3} binary phase diagram. It is the figure which showed the combined state of the mixture before and behind sintering (before and after baking), and a sintering raw material. It is a related figure of the compounding quantity of a 1st mixture in case a production rate is 2.3-2.5 (t / m < ² > / h), and a yield. It is a related figure of the compounding quantity and yield of a 1st mixture when a production rate is 1.7-1.9 (t / m < ² > / h).

The manufacturing method of the iron ore sintered ore of the present invention will be described.
Conventionally, in a blast furnace, an iron ore (or ore) containing iron ore is introduced from the upper part of the furnace body and hot air is blown from the lower part. Pig iron is produced by a series of reactions such as reduction and dissolution. This blast furnace is a counter-current reactor that continuously performs heat exchange / reduction reactions with the gas ascending in the furnace. For this reason, it is important that the charge to be charged into the blast furnace, particularly the sintered ore, has a dust resistance (strength) that does not impede gas passage in the furnace and good reducibility.

Therefore, in the manufacturing process of sintered ore, calcium ferrite (hereinafter referred to as CF) is synthesized as much as possible, and by forming a connective structure due to the CF-based melt between the particles of the sintering raw material, strength and It becomes possible to produce a sintered ore excellent in reducibility.
In the process upstream of the blast furnace (sintering pretreatment process in the iron making process), for example, a sintered ore is manufactured using a dwelloid-type sintering machine in which a pallet is configured in an endless belt shape.

In this droite-type sintering machine, when producing sintered ore, first, ore, solid fuel (such as coke powder), pallet moving from the raw material supply side to the product (sintered ore) discharge side, Sintering raw material layers are formed by sequentially supplying and filling sintering raw materials composed of auxiliary materials and others. And by igniting the upper part of the sintering raw material layer and allowing air to pass downward, the combustion proceeds toward the lower part of the sintering raw material layer, and the firing of the sintering raw material is completed before reaching the product discharge side. By doing.

  Here, looking at the sintering process, the sintered raw material charged on the pallet contains solid fuel (coke powder) called a coagulant. When the combustion gas is further sucked by the blower, the frame accompanying the combustion of the solid fuel descends in the sintering material layer, and the sintering material is heated and heated around and below the frame. The part where the frame has already passed is continuously cooled by the gas supplied from above. In the sintering raw material layer, the heat pattern at a certain fixed point from when it is charged on the pallet until it is discharged is as shown in FIG.

Now, if a CaO source is included in the sintering raw material, the temperature is raised during the sintering, and when the temperature exceeds a certain temperature, synthesis of CF is started by a solid-phase reaction between the iron ore and the CaO source. When the melting point of CF is reached, a part of the synthesized CF is eluted as a melt between the particles of the sintering raw material. In the subsequent cooling process, this solidifies to form a connective structure that firmly bonds the sintered raw materials.
Since the connective tissue is formed by solidifying what is eluted as a melt, if the heat pattern is the same, the time during which connective tissue can be formed is the time when the CF that has already been synthesized by solid-phase reaction is used. It is thought to be the time from melting to solidification. Conventionally, an approach and a technique for improving the heat pattern and extending the formation time of a suitable connective tissue have been reported. However, these prior arts involve major modifications of equipment and processes.

In the present invention, iron hydroxide having a structure of Fe ₂ O ₃ .nH ₂ O is used as a part of the sintering raw material, and as shown in FIG. 2, iron hydroxide, a CaO source, and powder coke are used. Mixing promotes the synthesis (generation) of CF.
When sintering is performed using iron hydroxide, the temperature is raised by heating as the sintering raw material layer as shown in FIG. 1 rises, and thermal decomposition starts at around 300 ° C. At this time, the iron hydroxide has a specific surface area and a surface property that is very active. When there is a CaO source in the vicinity of such surface-like iron hydroxide, synthesis of CF by a solid-phase reaction is started at a lower temperature than before.

  That is, even if sintering is performed with the same heat pattern as in the past, by mixing iron hydroxide ore and CaO source as in the present invention and proceeding with sintering, solid phase reaction can be performed from an early stage. CF can be synthesized, and the CF time by solid phase reaction can be lengthened. That is, as shown in FIG. 1, conventionally, for example, CF synthesis was started at arrow B in FIG. 1, but in the present invention, CF synthesis can be started at an early stage of arrow C. .

As a result, when the CF melting start temperature is reached (when entering the section A in FIG. 1), a larger amount of CF-based melt is eluted than before, and a larger amount of CF-based connective tissue is formed during cooling. Can be formed. The section A is an example of a connective tissue formation section (time from elution of CF melt to solidification).
As described above, it is thought that by mixing Fe ₂ O ₃ .nH ₂ O iron hydroxide, a CaO source, and powdered coke, CF synthesis can be accelerated to produce a large amount of CF. In order to promote the synthesis of the above, it was considered advantageous to use particles having a large reaction interfacial area and high surface reactivity, and verified what kind of iron hydroxide was suitable.

The iron hydroxide that is Fe ₂ O ₃ .H ₂ O (n = 1) is called goethite, but when this goethite is used, as shown in FIG. 3 and FIG. The yield of the charge is not improved, and it is not possible to use a goethite where n = 1 substantially. Further, it is considered that n = 0 to 1 is composed of n = 1 goethite and Fe ₂ O ₃ (hematite) containing no bound water. Even if it is, the yield of the charge is not improved as in the game site.

On the other hand, when a hydroxide having n of more than 1 (n> 1) is used for sintering, a large amount of heat is required for decomposition of the bound water in the process of firing, and extra firing energy is required. It has been considered undesirable to use iron hydroxide for sintering. In other words, when iron hydroxide is used as part of the raw material constituting the sintered raw material particles, it is generated in the sintered ore raw material particles due to heat shortage due to the endothermic reaction accompanying the decomposition reaction of bound water and the release of water vapor during decomposition. Due to the cracking, the contact between the particles is insufficient, and further, it becomes difficult for the CaO source for forming CF to be present in the vicinity of the iron hydroxide, and in a solid state in the particles of the sintering raw material. It has been considered that the synthesis of CF does not proceed efficiently, the strength of the connective structure of the sintered ore decreases, and the yield also decreases. For this reason, as a matter of course, it has never been conceived so far to use iron hydroxide, which has a stronger effect of bonding water than when n exceeds 1.0, as a means for bonding sintered raw materials.

However, the inventors have continued to verify iron hydroxide whose n exceeds 1.0 without being caught by the conventional idea. As a result, it was found that when a hydroxide with n exceeding 1 (n> 1) was used for sintering, the yield of the charge could be improved as shown in FIGS. .
It should be noted that iron hydroxide (iron hydroxide or hydroxide ore) is expressed as Fe ₂ O ₃ .nH ₂ O is technical literature: “Steel production method, 3-1 raw material, Table 3.1 iron ore. No. 4, 163, Japan Iron and Steel Institute book, published on April 10, 1972, Maruzen Co., Ltd., and is well known among those skilled in the art. Also, in iron hydroxide, for example, as shown in "Lecture: Modern Metallurgy, Volume 1 Steel Smelting, Japan Metallurgy Society, Issue 1 pp. Pp. 98-99" In addition, it is known that the value of n does not exceed 4 mineralogically. The n of iron hydroxide is a coefficient expressing the amount of compound water, and can be determined by thermal analysis and chemical analysis. Specifically, the valence is the total iron number tFe (JIS M8212 total iron determination method), divalent iron (JIS M8213 divalent iron determination method), FeO and compound water (JIS M8211 compound water determination by chemical analysis). Method) and the amount of CW. The valence n is obtained by n = W / Hm × 2 (however, Hm = tFe / 55.85-FeO / 71.85, W = CW / 18).

That is, in the present invention, when mixing iron hydroxide, a CaO source, and powdered coke, iron hydroxide having n of Fe ₂ O ₃ · nH ₂ O exceeding 1.0 and not more than 4.0 is used. It is said. Hereinafter, for convenience of explanation, a mixture of iron hydroxide and a CaO source is referred to as a “first mixture”, and a mixture of iron hydroxide, a CaO source and powdered coke is referred to as a “second mixture”.
Now, the CaO sources used for mixing are quicklime CaO, slaked lime Ca (OH) ₂ , and limestone CaCO ₃ . In mixing the iron hydroxide and the CaO source, any one or more of quick lime, slaked lime, and limestone may be used. Limestone and slaked lime decompose upon heating to produce CaO. Further, quick lime, slaked lime, and limestone may be mixed and used. In producing a sintered ore, JP 2004-315277 A discloses an example in which gypsum is used. However, in this method, it is necessary to remove Ca, which is an impurity, and desulfurization. Since a process is required, it is difficult to use industrially.

As described above, CF is synthesized by a solid phase reaction between iron hydroxide and a CaO source during heating and heating. In order to synthesize this CF without excess or deficiency, CaO-Fe _{2 in} FIG. As shown in the O ₃ binary phase diagram, the range D including the lower limit temperature of the liquidus may be set. That is, in mixing the iron hydroxide and the CaO source (first mixture), the molar ratio of CaO to Fe ₂ O ₃ (CaO / Fe ₂ O ₃ ) is more than 0.5 and more than 2.0. What is necessary is just to make it small.

  Moreover, in this invention, it is supposed that a 2nd mixture will be produced | generated by mixing powder coke with the 1st mixture which mixed iron hydroxide and the CaO source. Here, the particle size of the powder coke used for mixing is 1000 μm or less. In other words, powder coke having a particle size of 1000 μm or less is incorporated in the second mixture. Powdered coke becomes a heat supply source and easily creates a reducing atmosphere, so that CF is easily generated. When the particle size of the powder coke exceeds 1000 μm, the reactivity and dispersibility are lowered, so that the effect of supplying heat and reducing atmosphere in the powder coke cannot be sufficiently obtained.

Moreover, in the 2nd mixture, the mass ratio of the powder coke with respect to the 2nd mixture shall be 2-20%. The mass ratio of the powder coke is a value obtained by [mixed powder coke ÷ second mixture × 100]. That is, as shown in FIG. 2, the mass ratio of the powder coke is the ratio of the powder coke to the second mixture. When the mass ratio of the powder coke is less than 2% by mass, the effect of supplying heat and reducing atmosphere in the powder coke cannot be sufficiently obtained. On the other hand, if the mass ratio of the powder coke exceeds 20% by mass, the powder coke may hinder the proximity of the iron hydroxide and the CaO source.

Thus, in addition to mixing of iron hydroxide and a CaO source, the production of CF can be promoted by mixing powdered coke.
FIG. 6 shows a bonding state between the second mixture (iron hydroxide, CaO source, powder coke) before and after sintering (before and after firing) and the sintering raw material. As shown in FIG. 6A, before sintering, the second mixture 1 and another sintered raw material (referred to as other raw material) 2 different from the second mixture 1 exist in separate states. Yes. As shown in FIG. 6 (a), when sintering proceeds in a state where the second mixture 1 enters between the other raw materials 2 and 2 (between particles of the sintered raw material), a large amount of the mixture 1 is heated from the mixture 1 during heating and heating. CF (CF solution) is eluted, and the eluted CF solution is assimilated with the other raw material 2, and after sintering, the other raw materials 2 are bonded to each other by a strong connective structure 3 as shown in FIG. 6B. .

Thus, in order to firmly bond the other raw materials with the CF solution eluted from the mixture, the first mixture is charged (mixed) in an amount of 2% by mass or more and less than 30% by mass with respect to the other sintered raw materials. To do.
As shown in FIGS. 7 and 8, when the blending amount of the first mixture with respect to other raw materials is less than 2% by mass, a sufficient amount of connective structure cannot be formed in the sintered raw material layer, and the yield is Does not improve. That is, if the mixing of the first mixture with the other raw material is small, the ratio of the first mixture between the particles of the other raw material is small compared to the entire sintered raw material layer, so the strength of the entire sintering raw material tank The improvement was not achieved and the yield could not be improved sufficiently.

  When the blending amount of the first mixture with respect to the other raw materials is 2% by mass or more, the yield is rapidly improved. As the charging amount of the first mixture is gradually increased from 2% by mass, the total amount of CF melt eluted from the first mixture increases. Although a certain amount of CF melt acts as a connective structure and contributes to the bonding of other raw materials, the excess CF melt that did not work as a connective structure is located below the sintered raw material layer due to the downward ventilation during sintering. Although it moves, it may solidify in the middle of the sintering raw material layer (for example, in the vicinity of the middle lower layer portion), possibly inhibiting the blower. That is, when the CF melt moving by the downward air flow is excessive, the gas passing through the sintering raw material layer drifts, increasing the generation rate of the so-called non-uniform sintered structure called burn unevenness, and increasing the yield. May decrease.

As shown in FIGS. 7 and 8, when looking at the blending amount of the first mixture with respect to the other raw materials and the state of the yield, the blending amount of the first mixture with respect to the other raw materials exceeds 2 mass% and less than 30 mass%. Although the yield was improved, the yield decreased when the blending amount of the first mixture exceeded 30% by mass.
Summarizing the above, in the present invention, the FeO2 · FeH ₂ O ₃ molar ratio of Fe ₂ O ₃ .nH ₂ O is more than 1.0 and less than 4.0 and the CaO source is 0. The first mixture is formed by mixing so as to be more than 5 and less than 2.0. And the 2nd mixture is supposed to be formed by mixing the powdery coke whose particle size is 1000 micrometers or less with the 1st mixture. And it is supposed to manufacture a sintered ore by sintering a 2nd mixture and another sintering raw material.

In addition, the mass ratio of the powder coke with respect to a 2nd mixture is 2-20%, and the mixture ratio of a 1st mixture and another raw material is 2 mass% or more and 30 mass% with respect to another sintering raw material of a 1st mixture. It is supposed to be charged so that it becomes less.
Here, in mixing iron hydroxide, a CaO source, and powdered coke, it is desirable to grind while mixing iron hydroxide, a CaO source, and powdered coke (sometimes referred to as a mixed grinding method). . When mixing the iron hydroxide, the CaO source, and the powder coke, the mixing and pulverization are performed at the same time, so that the iron hydroxide and the CaO source come close to each other and react easily due to the mechanochemical effect.

That is, in the mixing and pulverizing method, the mixing of iron hydroxide and the CaO source is made uniform as compared with the method of mixing the powdered coke after pulverizing the iron hydroxide and the CaO source (mixing method after pulverization). Proximity.
Now, as described above, when performing the sintering, the second mixture containing iron hydroxide, the CaO source and the powdered coke, and other raw materials are charged into the pallet of the sintering machine. It is desirable to use a granulated material such as pellets. That is, it is desirable that the second mixture is granulated to obtain a granulated product, and then the granulated product and another sintering raw material are charged and sintered. By making the second mixture as a granulated product such as a pellet, the constituent particles of iron hydroxide and CaO source are close to each other, improving their reaction efficiency and generating more CF at low temperature. Is possible.

  Here, the granulated product with a particle size of 1 mm or less is 10% by mass or less, and the granulated product with a particle size of 10 mm or more is 10% by mass or less with respect to the total sintered raw material. When a granulated product having a particle size of 1 mm or less is charged into the sintered raw material layer, the packing density increases (the porosity decreases). If there are too many granulated products of 1 mm or less, air permeability will be hindered and pressure loss will increase, so that the granulated products of 1 mm or less are 10 mass% or less. On the other hand, in the case of a granulated product of 10 mm or more, the temperature rise in the granulated product is slowed or the drift of the sintering raw material layer is promoted.

Now, when the mixture is granulated to obtain a granulated product, it is preferable that SWR (Slaking Water Ratio) = 0.3 to 0.8. SWR is called a granulated water content (digested water content) at the time of granulation, and can be calculated by “SWR = mass of water ÷ mass of quick lime” when the CaO source is quick lime.
When SWR <0.3, the digestion reaction [CaO + H ₂ O → Ca (OH) ₂ ] is slow, the pores become coarse due to the long-time reaction, the specific surface area becomes relatively low, and inert slaked lime End up. On the other hand, when SWR> 0.8, the reaction proceeds rapidly and the peak temperature becomes high, but since the reaction time is short because pores are immediately cooled by excess water and the pore growth is insufficient, the specific surface area is low. It becomes inactive slaked lime.

On the other hand, when granulated so that the SWR is 0.3 or more and 0.8 or less, the slaked lime in the granulated product (pellet) is active, so it reacts with iron hydroxide (iron ore), CF formation can be promoted at a low temperature.
When the mixture is granulated into a granulated product, it is desirable to granulate iron hydroxide, a CaO source, and powdered coke using a high-speed stirring mixer. The high-speed agitating mixer rotates the whole container (bread) containing raw materials to be granulated, and rotates the agitator (mixer) inserted in the container in the opposite direction to the container for granulation. The container (pan) is inclined, and the agitator is disposed such that the rotation center of the agitator and the center of the container are eccentric. In addition, a scraper that peels off the raw material attached to the inner wall of the container is provided in the container.

By producing a granulated product using a high-speed stirring mixer, it is possible to generate a high shearing force on the raw material (the raw material of the mixture) and to mix it precisely and uniformly.
Tables 1-16 summarize the examples sintered by the method for producing a sintered ore for iron making according to the present invention and comparative examples in which sintering was performed by a method different from the present invention.

In Examples and Comparative Examples, sintering was performed using a test sintering machine. This test sintering machine is a sintering pan having a diameter of 300 mm and a height of 350 mm, and this sintering pan is made of steel and has a grading bottom surface so that air can be sucked downward. The component target of the sintering raw material was SiO ₂ : 7.0 mass%, CaO: 18.0 mass%, Al ₂ O ₃ : 1.8 mass%, and the pseudo particle average particle size was about 3 mm. Ore A, the raw material for sintering, was mined in Hamasley (
Hamasle) ore B is made of Rio Doce. In the sintering test, a second mixture containing iron hydroxide, a CaO source (quick lime, slaked lime, limestone) and powdered coke, and raw materials such as ore A, ore B, limestone and dolomide are mounted in a test sintering machine. Then, the surface was ignited by an ignition burner, and air was sucked from below and baked. When the flame reached the bottom of the test sintering machine (sintering pan), it was finished and cooled. After sintering, the sintered cake was dropped on the iron plate 4 times from a height of 2 m, and the mass ratio of the sintered ore of 5 mm or more after being dropped 4 times was taken as the yield. That is, the yield was determined by the mass of sintered ore having a particle size of 5 mm or more / the mass of sintered cake. The production rate was determined by “Production rate = mass of sintered ore having a particle size of 5 mm or more / effective area of the sintering machine / sintering time”. The sintering time was defined as the time required for the flame to reach the lowest layer from ignition in a test sintering machine.

  The coke breeze in the table serves as a heat source for sintering, and -3 mm powder coke is used. This coke breeze is a mixture of the above-described iron hydroxide, CaO source and powder coke. It is distinguished from the powder coke in the second mixture (iron hydroxide + CaO source + powder coke) produced in this way. The ratio of the coke powder at the time of sintering is the total number of coke breeze (−3 mm) + powder coke and is the external number of the sintered raw material.

  In the examples and comparative examples, when the second mixture was produced (formed), either the above-described mixing and pulverization method or the mixing method after pulverization was used (column of mixing or mixing and pulverization after pulverization). Moreover, it divided into the case where the 2nd mixture is granulated, and the case where a mixture is not granulated (column of the state of a mixture), and when granulated, while measuring a particle size, the SWR value was also calculated | required. Furthermore, when granulating, it divided into the case where it granulated with the bread pelletizer as usual, and the case where it granulated with the high-speed stirring mixer. The pan pelletizer was granulated while rotating a container (pan) having a diameter of 400 mm at a rotation speed of 45 rpm. In the high-speed stirring mixer, a container (pan) having a diameter of 240 mm and a height of 250 mm was rotated at 87 rpm, and the rotational speed of the agitator was 850 rpm.

Embodiments Example 1 to _144, and 4.0 or less iron hydroxide exceed Fe ₂ O 3 · nH ₂ O n is 1.0, and a CaO source molar ratio of CaO / _Fe 2 _{O 3} is 0.5 The mixture is mixed so as to be less than 2.0 and less than 2.0 to form a first mixture, and powder coke having a particle size of 1000 μm or less is mixed with the first mixture to form a second mixture. The mass ratio of the powder coke to the second mixture was 2 to 20%. Moreover, it is supposed that 2 mass% or more and less than 30 mass% of the 1st mixture is charged with respect to another sintering raw material.

  Furthermore, in Examples 1-10 and 73-82, iron hydroxide, a CaO source, and powder coke were mixed by a mixing method after pulverization, and the second mixture was not granulated (not formed into a mini-pellet shape). . In Examples 11 to 20 and 83 to 92, iron hydroxide, a CaO source, and powdered coke were mixed by a mixed pulverization method, and the second mixture was not granulated (not made into a mini-pellet shape). In Examples 21 to 40 and 93 to 112, the second mixture was granulated by mixing iron hydroxide, a CaO source, and powdered coke by a mixed method after pulverization or a mixed pulverization method. In Examples 41-56 and 113-128, iron hydroxide, a CaO source, and powder coke are mixed by a post-grinding mixing method or a mixed grinding method so that SWR falls within a range of 0.3 to 0.8. Granulation was performed.

In Examples 57-72 and 129-144, the 2nd mixture was granulated using the high-speed stirring mixer.
On the other hand, in Comparative Examples 1 to 89 and 111 to 199, the valence n of iron hydroxide (Fe ₂ O ₃ · nH ₂ O), the molar ratio of CaO / Fe ₂ O ₃ , other sintering raw materials of the first mixture At least one of the blending amounts is different from that defined in the present invention. Comparative Examples 90-110 and 200-220 are the composition of the powdered coke with respect to the first mixture, the particle size of the powdered coke, the particle size of the granulated product after granulating the second mixture, and when granulating the second mixture. Any of the SWR values are different from those specified in the present invention.

As described above, in the present invention, the n valence number of Fe ₂ O ₃ .nH ₂ O is “1.0 <n ≦ 4.0”, and the molar ratio in mixing iron hydroxide and CaO source is “0.5 <CaO / Fe ₂ O ₃ <2.0 ”, the particle size of the powder coke is“ 1000 μm or less ”, the mass ratio of the powder coke to the second mixture is“ 2 to 20% ”, and the first mixture with respect to the other sintered raw materials is“ 2 mass ”. When the production rate is 2.3 to 2.5 t / m ² / h (high production rate), the yield is about 59% (± 0.2). When the production rate was 1.7 to 1.9 t / m ² / h (low production rate), the yield could be around 76% (± 0.2).

  In addition to the condition A, the condition B mixed by the mixing and pulverizing method was able to achieve a yield of around 60% at a high production rate and a yield of around 77% at a low production rate. Further, the second mixture is granulated, and the granulated product after granulation is subjected to sintering by adding the condition C in which 1 mm or less is 10 mass% or less and 10 mm or more is 10 mass% or less in addition to the condition A. In this case, the yield was around 61% at the high production rate and the yield was around 78% at the low production rate. When sintering was performed by adding the condition C to the conditions A and B, the yield could be around 62% at the high production rate, and the yield could be around 79% at the low production rate.

Moreover, when the 2nd mixture is granulated so that it may become SWR = 0.3-0.8 after setting a CaO source as quicklime, with respect to the result in the conditions C, a yield is raised about 1%. We were able to. Further, when granulation is performed with a high-speed stirring mixer, the yield is about 1% compared to the case where sintering is performed by adding Condition A, Condition B, Condition C, and SWR = 0.3 to 0.8. I was able to raise it.
That is, according to the present invention, as described above, inferior iron ore that has been considered to be unusable in the past (iron hydroxide with a valence n exceeding 1.0, in other words, ore containing ultra-high crystal water) Was used to improve the yield.

  In the embodiment disclosed this time, matters not explicitly disclosed, for example, operating conditions and operating conditions, various parameters, dimensions, weights, volumes, etc. of components deviate from the areas normally practiced by those skilled in the art. However, matters that can be easily assumed by those skilled in the art are employed.

1 Second mixture 2 Other raw materials 3 Connective tissue

Claims (4)

And _{Fe 2 O 3 · nH 2 O} n is 1.0 to greater than 4.0 following iron hydroxide, and a CaO source molar ratio of CaO / _Fe 2 _{O 3} is less than 2.0 more than 0.5 The first mixture is produced by mixing so as to produce a second mixture by mixing powder coke having a particle size of 1000 μm or less with the first mixture,
The second mass ratio of the powder coke to a mixture and 2-20%, wherein the first mixture with less than 30 wt% or more 2% by weight relative to the other sintering material, the other with the second mixture of by sintering a sintering material, a manufacturing method of iron making sinter, characterized by producing a sintered ore. The second mixture is granulated to obtain a granulated product, and then the granulated product and other sintered raw materials are charged. With respect to the particle size of the granulated product, 1 mm or less is 10% by mass or less. the method of iron making sinter according to claim 1 or 10mm is characterized by a 10% by mass or less. When the second mixture is granulated to obtain a granulated product, the CaO source is quick lime, and the SWR represented by “mass of granulated water ÷ mass of quick lime” is 0.3 or more and 0.8 or less. The manufacturing method of the sintered ore for iron manufacture of Claim 2 characterized by the above-mentioned. Wherein when the second mixture granules by granulating a method for producing a steel for sinter according to claim 3, characterized in that there use a high-speed stirring mixer.