JPS5935970B2 - Method for manufacturing sintered ore - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing sintered ore, which aims to reduce the blast furnace fuel ratio and Si content in pig iron without reducing the productivity, coke consumption rate, and quality of sintered ore. The purpose is to obtain a method that can accurately produce concretions,
Furthermore, the permeability of the sintering bed is ensured so that the reaction can be carried out effectively to obtain a preferable sintered ore with strengthened calcium ferrite slag bonds.

The sintering process in a sintering machine such as the toroidroid type involves combining the raw materials such as iron ore, miscellaneous raw materials, slag forming agent, coke, etc., adding water, granulating it, and then charging it into the sintering machine. Then, by igniting the surface layer of the raw material in an ignition furnace and sucking air downward, the coke in the raw material is burned, and the heat generated causes a sintering reaction or melting of the raw material particles (
By attempting a semi-molten) reaction and cooling it, a mineral composition with high porosity and completely different from that of the raw iron ore is formed.

The goals of such sintering operations are to satisfy quality standards, improve productivity, and reduce coke consumption, so productivity is usually maintained within the range that maintains the quality of the sintered ore. Operations are aimed at improving coke consumption and reducing coke consumption.

By the way, when considering the properties of conventional blast furnace charging raw materials (for example, sintered ore, pellets, etc.), the temperature range that became a problem was 1200°C or less.

The strength, reducibility, reduction pulverization property, swelling property, etc. of the lumpy zone before the charging material softens and fuses have been studied and quality controlled, but the results of a recent concrete blast furnace dismantling investigation have been The existence of a cohesive layer was confirmed, and it was found that this cohesive zone has a large effect on the gas flow and permeability in the blast furnace.From these results, the properties of the raw material charged to the blast furnace are Higher temperature range than the problem temperature range (i.e. 1200℃ or higher)
Emphasis has been placed on improving properties during softening, fusion, melting, and dropping, that is, high-temperature properties.

Loaded softening and melting tests have been conducted for the purpose of more accurate measurement and evaluation of the high temperature properties (reducibility, softening and melting characteristics at high temperatures, and associated changes in air permeability) of raw material charged to a covered blast furnace. The causes of differences in the high-temperature properties of sintered ore are directly due to the amount of melt produced during the slag assimilation reaction process, and indirectly due to the reducibility at high temperatures of 1000°C or higher and the temperature before reduction. Among these, the reduction in the amount of gangue of sintered ore (Cab
It was confirmed that reducing the amount of Si (at a constant amount of Si/SiO2) greatly improved the high-temperature properties, and that it was possible to significantly reduce the blast furnace fuel ratio as well as reduce the amount of slag in the blast furnace.

However, sintered ore with low 5i02, such as SiO2 of 5.2 or less, which reduces the amount of gangue in the blast furnace, is
It is easily pulverized in a reducing atmosphere in the temperature range of 00℃, and the reduction pulverization index (RDI) is one of the current quality control items.
After 900 rotations of sintered ore held in a reducing atmosphere at 550°C for 30 minutes in a drum, the weight ratio of 13772W deteriorates significantly, and the sintering time becomes longer, resulting in a decrease in production rate or a constant production rate. The disadvantage is that the yield and strength (SI) are reduced when maintained at a low temperature.

However, there have been several proposals by Mr. Tashiro and others regarding the production of this low 5i02 sintered ore, but these proposals involve increasing the amount of 5i02 in the fine powder portion of less than 1 mm by pulverizing the SiO□ source, C of this fine powder part
ao/S i 02 or Cab/(Si02- At
203) below a certain level 7, or the fine powder part is made to have a coefficient of 55 or higher, and the raw material preheating of the fine powder adjusted in this way is also used, in short, the silicate slag bond expected with the reduction of SiO2 The aim is to compensate for the decrease in production by pulverizing the 5i02 source and increasing the effective amount of SiO□.

However, even if low 5i02 is achieved in this way, there is a limit as long as silicate slag is used as a bond.Therefore, in order to obtain a desirable low SiO2 for sintered ore, considerable selection must be made regarding the brand of ore to be blended. In addition, for this reason, it is impossible to continue for a long period of time, and it becomes difficult to continue stable low 5i02 operation.

The present invention was created after repeated studies in view of the above-mentioned circumstances.
No 5i02-based slag-forming agent containing 3 or more O2 is used, and dolomite and limestone crushed to a total amount of less than 0.5 m are used as Cab and MgO-based slag-forming agents, and 5i02 of sintered ore is used. It is characterized by adjusting the 5in2 content of the blended raw materials so that the content is between 4.6 and 5.4, and it is proposed to sinter such blended raw materials, thereby increasing the sintering rate. By reducing the amount of gangue by reducing the amount of 5i02 in the ore, the reduction index (RDI) and cold strength can be appropriately obtained, and the sintered ore can be produced without deteriorating productivity or coke consumption. The aim is to improve the high-temperature properties of iron and reduce the blast furnace fuel ratio and Si content in the pig iron by reducing the formation of blast furnace slag.

In addition, in the present invention, dolomite and limestone used as Ca Op MgO-based slag forming agents are sieved with a 2 mm classification point, and the upper part of the sieve, which accounts for around 20%, is used as it is, while the lower part of the sieve is used as is. The total volume is Q, 5 m7
By pulverizing and blending to less than Obtain ore.

Furthermore, the CaO/SiO2 of the fine powder part less than 0.5 is 3 to 8.
To make the reaction more effective, the amount of gangue (CaO + 5iO2) in the fine powder part can be controlled to be 7.
% or more and CaO/SiO2 as above.
-8 similarly enable the reaction to be made effective, thereby advantageously achieving the above-mentioned objects of the present invention.

To explain the present invention as described above, in the sintering reaction of self-fusing sintered ore, there is little diffusion bonding as a solid phase reaction, and most of the bonding is through the molten phase, so the role of the melt is extremely important. is important.

Moreover, the average structure is a so-called fusion bond type in which iron oxide particles are bonded by slag, and the quality and productivity of the sintered ore are greatly influenced by this slag bond.

However, in the current process using a Dwight Lloyd sintering machine, the reaction time at high temperatures is extremely short, and since the heating is not completed until it is completely molten, bonding proceeds through the partially formed melt. An important issue is how to quickly and uniformly form gangue into slag.

This is especially important when producing low 5i02 sintered ore by reducing the amount of gangue. It is necessary to compensate by means of

By the way, sources for this slag have traditionally been CaO-based limestone, quicklime, slaked lime, 5i02-based silica stone, silica sand, and MgO-based sources such as CaO-based raw dolomite, lightly calcined dolomite, and 5i0
2 series serpentine, Ni slag or Cab, 5i02y
Ores whose main component is gangue components such as MgO have been used, and the slag composition, amount, etc. have been adjusted using these ores.

However, in the sintering process, a melt is generated from a combination of particles that are likely to form a melt in a mixed powder of various chemical compositions, that is, a combination of particles that correspond to a chemical composition region with a low melting point.
As the temperature rises, the amount increases and spreads, and bonding progresses through reactions and coalescence between the melts, but because the residence time at high temperatures is short, coarse grain raw materials or raw materials with poor slagability are not completely melted and remain unreacted. It often remains.

In conventional sintered ore manufacturing operations, Sin22Mg0-based slag agents such as serpentinite, Ni slag, and silica stone, which have poor slag forming properties, often remain as the original ore, and additive slag agents do not fully utilize their effects. It is difficult to demonstrate one's ability.

The present inventors conducted various experiments and studies regarding these points, and as a result, they aimed to reduce 5i02 in sintered ore by not using the aforementioned SiO□-based slag-creating agent, which has poor slag-forming properties. We use only Cab and MgO-based sludge-forming agents (dolomite, limestone), which have relatively good sludge-forming properties, and also use Q,
The particle size should be adjusted to less than 5 mm before use, and further, it should be sieved at a classification point of 2 mm, and the upper part of the sieve should be used as it is, and only the majority of the lower part should be pulverized into Q, 511!771 and below. I learned that the key point when sintering with a low amount of gangue is to use

In addition, CaO/SiO2 in the fine powder part of less than 0.5 is set to 3 to 8, or (CaO+5
i02) amount is 7% and CaO/5i02 is 3~
I learned that it is important to set it to 8.

CaO as a first approximation of the main gangue components of self-fusing sintered ore
2SiO2, and considering the generation process of melt in sintered ore using the Cab-8in2 iron monoxide system, if the oxygen potential is high, it can be handled with the CaO-8iO□-Fe203 system, so as shown in Part 1, 1300 Two low melting point chemical composition regions A and H below ℃ are recognized.

In other words, there are two types of combinations of particles that generate melt at a relatively low temperature of 1300°C or less: silicate region A and calcium ferrite region B, but considering the probability, they are similar to sintering raw materials. In systems with a large amount of iron oxide, CaO-
The probability of turning into a melt is much higher for the Ca0-iron oxide combination than for the 8iO□-iron oxide combination.

That is, in the sintering process, the contact point between CaO and iron oxide generates low melting point calcium ferrite through a solid phase reaction, and there is a high probability that a melt will be generated and react with it, as shown in Table 1 below. Since its reactivity is also extremely good compared to other systems, if the amount of gangue (SiO2 amount) at least promotes the reaction between CaO and iron oxide, calcium ferrite slag bond can be used instead of the conventional silicate slag bond. The bond will be strengthened, and the quality and productivity of sintering will be sufficiently maintained and improved.

○ mark: Melts in 5 minutes at 1250℃ ×: Not melted in 5 minutes at 1400℃ However, reactions due to solid phase diffusion are excluded.

In the above-mentioned case, the combined use of 5i02-based slag-forming agents should be avoided; that is, as can be seen from Figure 1 above, if melts with locally different compositions coexist during the sintering process, , the reaction between the melts cannot be achieved unless the temperature exceeds a certain level (for example, 1315°C or higher in the case of A and B), and the A and B have two valleys on the liquid phase surface, and a high temperature occurs between them. Because there is a melting point chemical composition region, 1315
This is because if they physically collide and react at temperatures below ℃, the interface will solidify and the reaction will no longer proceed.

Therefore, in order to quickly turn gangue into slag, SiO2
Suppresses the generation of silicate-based melt without using slag-forming agents,
It is important to preferentially generate a calcium ferrite-based melt to accelerate the reaction.

Furthermore, in order to promote the reaction between CaO and iron oxide, Ca
It is necessary to increase the chance of contact between O and iron oxide.

Generally, the sintered raw materials are mixed and granulated in the mixing and granulation process as shown in Figure 2.
Pseudo-particles are formed around the aggregated core of ~5 mm with fine particles of less than 9.5 mm adhering to it, but 1 to Q, 5
RNM particles often exist alone without forming nuclei or adhesion resistance.

Therefore, in order to make close contact between CaO and iron oxide, all CaO = MgO slag forming agents such as dolomite and limestone were used.
The content of the slag source can be reduced by finely pulverizing it to less than 5 mm to make it stick to the core of iron oxide particles and promoting the reaction between them, that is, by preferentially generating calcium ferrite slag bonds. Even if the amount of gangue decreases, it increases its contribution to the reaction and improves productivity even from sintered raw materials with a low amount of gangue (SiO2 amount).
It becomes possible to produce sintered ore of excellent quality.

In the present invention, limestone (CaCO5) and dolomite (MgCO3/CaC03), which are both CaO-based sludge-forming agents, were used to adjust the components of CaO and MgO, but other CaO-based sludge-forming agents, such as quicklime (Ca0), Slaked lime (Ca
Of course, similar effects can be obtained if (OH)2), light calcined dolomite (MgO-CaO), etc. are used after being refined to a particle size of less than 5 mm.

In addition, when seawater magnesia, magnesia clinker-1 magnesium hydroxide, etc. are used to adjust the MgO component, if the particles are refined to less than Q, 5 i7W, as shown in Figure 3, the amount of MgO and iron oxide will be reduced. The reaction produces a large amount of magnetite-magnesia ferrite solid solution (which is diffracted as magnetite), and the effect according to the present invention can be obtained.

Therefore, the Cab, MgO-based slag-forming agent of the present invention means all of the above-mentioned CaO-based and MgO-based slag-forming agents that do not contain 3% or more of SiO□.

In the specific implementation of the present invention, the above-mentioned fine slag forming agent is sieved at a 2 mm classification point as necessary, and coarse particles of 2 WtrIL or more on the sieve are kept at the same particle size to ensure air permeability. It is used after being pulverized to a size of 2 mm or less.

In other words, the sieved grains (2~
The air permeability in the sintering bed is improved as shown in FIG. 4 when a material with a diameter of 5 mm) is mixed, and the productivity can be improved.

However, if it is not possible to adjust the desired blending relationship only with particles of 2 nm or less in quantity, part or all of the coarse particles of 2 nm or more are pulverized, and Q, fine particles of less than 5 mm are considered to be a source of slag melt. (CaO+
5i02) The amount is 7 or more, and the CaO/5i0
Let 2 be 3-8.

That is, the relationship between the amount of (CaO+5i02) and the strengths S and I of the obtained sintered ore is as shown in FIG. 5, and -Q,
The relationship between 57W7W and the (CaO+S i 02 ) amount is as shown in Figure 5, and the strength of the sintered ore increases rapidly from the 6 to 7% portion, making it difficult to obtain a desirable product. can.

In this case, if the CaO/5i02 is maintained at 3 to 8, calcium ferrite melt can be preferentially produced quickly and in large quantities, and gangue (S
102) It is possible to produce sintered ore of excellent quality even from a small amount of sintered raw material.

The situation during this period is shown in Figure 1.CaO-S i 02
-Fe20. The low melting point region at 1200° C. or less is as shown in a part of the B region, and Q, which is the starting point of the melt, is CaO/5i02 in the fine powder part of 5 mtn or less from 3 to 8 as shown in the figure. By controlling this, the formation of a calcium ferrite-based melt during the sintering process is promoted, and a low melting point region C of 1200° C. or less can be appropriately obtained.

Regarding the relationship of FeO/S i O2, as shown in Fig. 6, the FeO of the fine powder part of 0.5 mm or less is
By setting /5i02 to 0.8 to 2.3, the generation of osobin-based melt during the sintering process is promoted, and the temperature at 1150°C
The following low melting point regions can be formed.

Furthermore, in the present invention, the 5i02 in the sintered ore is 4.6 to 5.
4%, and this relationship is separately discussed in Article 7.
This is summarized in the figure.

In other words, when 5i02 becomes less than 4.6, the production rate and strength decrease, and the RDI deteriorates, as shown in the upper part of Figure 7. On the other hand, when 5i02 becomes 5.4 or more, CaO-based When the slag forming agent is crushed, the RI is extremely deteriorated.

Therefore, the range that satisfies all of these production rate, strength, RDI and RI is 4.6 to 5.4% for 5i02.

In any case, by adjusting the blending ratio of CaO/5i02 and SiO2 as described above and preferentially producing calcium ferrite melt rapidly and in large quantities, the sintering raw material has a low gangue amount (Si02 amount). Productivity even from
It is possible to accurately produce sintered ore with excellent coke consumption and quality.

In other words, by increasing the reaction rate even if the amount of slag source added is reduced, sintered ore with improved quality and productivity can be appropriately obtained.

The conventional technology uses a SiO□-based slag-forming agent, so in order to reduce 5i02 in the sintering raw material, it is necessary to carefully select the brand of ore. As described above, it was impossible to continue for a long period of time, but the method of the present invention, which does not use any 5i02-based slag forming agent, eliminates the need to select ore brands.
It becomes possible to continuously produce a low SiO□ sintered ore with a SiO2 content of around 5% over a long period of time.

Furthermore, if you combine the selection of ore brands, temporarily 5i02
It is also possible to produce extremely low SiO2 sintered ore with a SiO2 content of around 4.6% or less.

A concrete example of the method of the present invention, together with a conventional method and a reference example for comparison, will be explained as follows.

Example 1 The following brands of iron ore, limestone, silica stone, dolomite, coke, return ore, etc. were prepared, and the specific composition of the conventional example I using these was as shown in Table 2 below. be.

-0.5mmcao = 2.17% This Table 2 contains 5.9% 5i02, and uses silica as the 5i02 source and dolomite as the MgO source.

The materials shown in Table 2 are prepared using a low SiO2 source in the usual manner, resulting in low SiO□ sintered ore (SiO□: 4.6-5.4%).
The following Table 3 shows a reference example of the compositions blended so as to achieve the following.

-0.5m1CaO=1.99% The specific 5i02 shown in Table 3 is 5,
It is of 4φ.

A specific example of the composition according to the present invention for these products is shown in Table 4 below.
The grains are refined to less than L and the amount of CaO is increased by less than 0.5.

However, the blended raw materials shown in Tables 2 to 4 above were granulated by adding water, and 50 kg of each of these was granulated.
A negative pressure of 1300 mmAq was sucked through a test pot to produce ladle burnt ore.

The production rate, strength (SI), product yield, reduction pulverization rate (RDI), and RI value of each of the obtained sintered ores are summarized in Table 5 below.

In other words, compared to Conventional Example 1, Reference Example 1 has a SiO
□With reduction in quantity, production rate, strength, product yield and RD
I deteriorates, and the sintering operation and properties of the sintered ore are greatly deteriorated.

In contrast to these, Example 1 of the present invention, in which the CaO source was refined to increase the amount of CaO to less than 0.5 mr/L, improved strength and product yield without deteriorating the raw material and mass ratio. ,
It was possible to significantly improve RDI and RI.

Example 2 The formulation of Conventional Example 2 using serpentine is as shown in Table 6 below.

-0.51nmCaO=2.18% Also, reduce the amount of SiO□ by a conventional method to obtain a low 5i02
The composition of Reference Example 2, in which sintered ore was produced, is as shown in Table 7 of Monokeji.

-0.5mmcao = 1.79% Furthermore, according to the present invention, limestone and dolomite, which are the CaO sources, are crushed in the same manner as in Example 1, and the total amount is Q. 0.5 m
The formulation of Example 2 of the present invention, which aims to increase the amount of CaO in the particle size range of less than m, is as shown in Table 8 below.

-0.5mwcao = 6.15% Sintered ore was produced in the same manner as in Example 1 for each of the formulations shown in Tables 6 to 8, and the production rate,
The results of measuring strength, product yield, etc. are summarized in Table 9 below. Similarly to the results of Example 1, Reference Example 2 shows the production rate, strength, product yield, and RD.
It was confirmed that, while I was deteriorated, the material according to Example 2 of the present invention significantly improved them.

Example 3 Same as in Example 1 described above, serpentine was not used and the blending ratio was exactly the same, that is, 6.4% of dolomite was used.
%, in those containing 8.5 parts lime and slag thickener,
The mixture was sieved using two grading points, and the upper part of the sieve was used as it was, while only the lower part was finely ground to a size of Q, less than 5 mm, and blended.

, that is, the formulation example according to the embodiment of the present invention in this case is the following first formulation.
As shown in Table 0.

-0.5 mmcao = 5.20% The conditions for the production of sintered ore are similar to those described in Example 1.

Example 4 Similar to Example 2, serpentinite was not used and the blending ratio was the same, but the material was sieved at the 2-city classification point as in Example 3, and only the bottom of the sieve was finely divided into Q, less than 5 mlL. It was crushed and blended.

Examples of formulations in this case are shown in Table 11 below.

-0,5,1mCaO=4.60% Moreover, the production of sintered ore was the same as in Example 1.

However, the specific production rate, strength, product yield, reduced powdering index, and RI for those according to Examples 3 and 4
The results were measured in the same manner as in Examples 1 and 2, and the results are shown in Table 12 below.

That is, it was found that the products according to Examples 3 and 4 had better air permeability and were even better in terms of production rate, etc., than those of Examples 1 and 2.

Example 5 Particle size adjustment was carried out so that CaO/5i02 in the fine powder portion of less than 0.5 wtm in the blended raw materials was 3 to 8.

That is, in the same manner as in Example 1, in which SiO2 was set to a ratio of 5.4, examples of formulations adjusted to satisfy the CaO/5i02 relationship of 5 are shown in Table 13 below.

-0,5mmcaO=6.94% -〇,5》SiO,=1.97 ratio -0,5mmcaO/S 102=3.52 Example
6 As in Example 5, a blending example in which CaO/5i02 in the fine powder portion of less than 0.5 pores is 3 to 8, and 5jO2 is 4.6 as in Example 2, is the following 14th example. As shown in the table.

-0.5mmcao=6.15% -0.5mmcao=1.79% 10.5mmcao/Si02=3.44
Example 5 in Table 13 and Example 6 in Table 14 were made into sintered ores in the same manner as in Example 1, but the production rate, strength, and finished product of the sintered ores produced in this way were The yield and other measurements were carried out in the same manner as in the above-mentioned Examples, and the results are shown in Table 15 below.

That is, the products according to these examples can greatly improve the quality of sintered ore (SI, RDI, and RI) while maintaining preferable productivity, appropriately reduce the amount of 5i02 in sintered ore, and reduce the blast furnace slag ratio. At the same time, it was confirmed that it is possible to improve the high temperature properties and reduce the blast furnace fuel ratio.

Example 7 Similarly to Examples 5 and 6 described above, the particle size was adjusted so that CaO/5i02 in the fine powder part less than 0.5 mm was 3 to 8, and (CaO+5i02 in the fine powder part less than 9.5 mm) ) amount to 7% or more.

That is, at the same blending ratio as Example 1, this more Ca,
Examples of formulations adjusted to satisfy the relationship between the amounts of 0/5i02 and (CaO+ Si02) are shown in Table 16 below.

In addition, the formulation composition relationship in the Q, less than 5 am fine powder portion of this product is shown in Table 17 below, together with those of Conventional Example 1 in Table 2 and Reference Example 1 in Table 3 shown in Example 1. It is as follows.

Example 8 Same as Example 7, Q, CaO/5 in the part less than 5 mm
Set i02 to 3 to 8, and (
The relationship between the amounts of Cab-)Si02) was determined according to the blending ratio of Example 2.

That is, the formulation example in this case is as shown in Table 18 below.

In addition, the compositional relationship between CaO and SiO2 in the fine powder portion of Q, 5 Wtm of this product is shown as follows, together with the corresponding compounding ratios of Conventional Example 2 and Reference Example 2 in Example 2. It is as shown in Table 19.

In Examples 7 and 8 described above, sintered ore was produced in the same manner as in Example 1.

That is, the production rate during the production of this sintered ore, the strength of the obtained sintered ore, the product yield, etc. were measured in the same manner as in the above-mentioned Examples, and the results are shown in Table 20 below. .

In other words, even in these embodiments, the quality of sintered ore can be greatly improved while maintaining desirable productivity, and advantageous blast furnace operation can be achieved by reducing blast furnace slag and improving high-temperature properties. This was confirmed.

According to the present invention as explained above, it is possible to improve the strength, product yield, reduction pulverizability, etc. without impairing productivity, and to reduce the fuel ratio and Si in pig iron in blast furnace operation. This invention is capable of accurately producing an advantageous sintered ore, and has great industrial effects.

In addition, in such embodiments of the present invention, air permeability in the sintering bed is ensured and calcium ferrite slag bonds are strengthened, or the amount of gangue in the sintered ore is reduced and its high-temperature properties are improved. At the same time, it is possible to provide sintered ore that appropriately reduces the blast furnace slag ratio and the blast furnace fuel ratio, and this invention is industrially highly effective in these respects as well.

[Brief explanation of drawings]

The drawings show the technical contents of the present invention, and Fig. 1 is a diagram showing the low melting point region in the Ca OS 102 Fe 203 system, and Fig. 2 is a diagram showing the relationship between initial deposition rate and particle size distribution. The diagram shown in Figure 3 is a diagram showing the relationship between MgO and the production amount of magnetite-magnesioferrite solid solution.
Figure 4 is a chart showing the relationship between the air permeability of the sintered bed and the proportion of coarse particles of 2 to 5.
A diagram showing the relationship between the amount of sinter in fine powder below Itm, Figure 6 is an explanatory diagram of the low melting point region below 1200℃ of CaO-8i02-FeO system, and Figure 7 shows the relationship between the amount of 5i02 and the productivity and characteristics of sintered ore. A diagram showing the relationship.

Claims (1)

[Scope of Claims] 1. As a slag-forming agent in the blended raw materials, a CaO/MgO-based slag-forming agent such as dolomite or limestone is used at 0.51 nm without using a SiO
5i02 of sintered ore is blended with
Si of the blended raw material is adjusted so that the content is between 4.6 and 5.4.
A method for producing sintered ore, characterized in that the amount of O□ is adjusted, and the mixed raw materials are sintered. 2. A method for producing sintered ore according to claim 1, in which the total amount of Ca (LMgO-based slag-forming agent is pulverized to less than 0.5 mm). 3. 2rIL of CaO/MgO-based slag-forming agent The claim is that the particles are sieved at the classification point of 'IIL, the particle size on the sieve remains unchanged, and the total amount under the sieve is pulverized to less than Q, 5 MAIL, and both the above and below the sieve are blended. 1st
Method for producing sintered ore as described in section. 4. A method for producing sintered ore according to claims 1 to 3, wherein the particle size is adjusted so that CaO/5i02 in the fine powder portion of less than 0.5WL71L in the blended raw materials is 3 to 8. 5 Using dolomite and limestone as CaO-MgO-based slag forming agents, Q, (C
aO/5i02) amount is 7% or more and the CaO
The method for producing sintered ore according to any one of claims 1 to 3, wherein the particle size is adjusted so that /5i02 is 3 to 8.