JP3252646B2 - Sinter production method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a sintered ore having good high-temperature properties and a low SiO ₂ concentration at a high yield. The sintered ore produced by this method is suitable for blast furnace operation in which the mixing ratio of the sintered ore is increased.

[0002]

2. Description of the Related Art A general process for producing a sintered ore charged into a blast furnace is as follows. That is, first, a raw material such as iron ore, fine coke, and limestone is granulated while adding an appropriate amount of water in a mixing granulator. Thus charged sintering material which is pseudo particles of the pallet of the sintering machine. Then, while sucking air from the upper part to the lower part of the sintering raw material packed layer, the upper part of the packed bed is ignited, and the coke breeze in the raw material is sequentially burned from the upper part to burn the sintering raw material. After firing, the pallet is tilted to take out a fired product (called a sintered cake), crushed and cooled, and thereafter, a sintered ore having a predetermined grain size or more is provided as a blast furnace raw material. A fired product having a particle size smaller than a certain particle size is returned to the sintering raw material as returned ore.

In recent years, high quality lump ore has been depleted,
Ratio of sinter ore to blast furnace charge (hereinafter “sintering ratio”
Operating methods have been becoming more common. Conventional baked ore 5.4 wt% or so of the SiO ₂ component as the main slag component, the MgO component containing about 0.5 wt%, the SiO ₂
According to the concentration, the blending of the blast furnace raw material is adjusted so that the CaO / SiO ₂ ratio becomes a constant value of about 1.6 to ₂ . Therefore, if the sintering ratio is increased while the SiO ₂ concentration of the sinter is kept constant, the amount of CaO source charged to keep the CaO / SiO ₂ ratio must be increased, and the unit The blast furnace slag amount per unit amount (blast furnace slag ratio) increases, and the fuel amount per unit tapping amount (fuel ratio) increases accordingly. In order to avoid such adverse effects on the blast furnace operation, a sintered ore having a low SiO ₂ concentration is required.

[0004] Conventionally, low SiO ₂ sintered ore has been produced by a method of reducing the amount of serpentinite, which is an SiO ₂ -based auxiliary material, and a method of using high-grade iron ore having a small gangue component. However, the only way to reduce the amount of serpentine is to use
・ Since it is an SiO ₂ -based auxiliary material, the MgO concentration of the sintered ore decreases at the same time due to the reduction of the blending amount. For this reason, there have been problems such as a decrease in the yield of the sintered ore, an increase in the ventilation resistance in the blast furnace due to the deterioration of the high-temperature properties of the sintered ore, and a hindrance to the slagging operation due to an increase in the viscosity of the slag. In addition, the method using high-grade iron ore has a disadvantage that a rise in raw material costs is inevitable.

Therefore, instead of using only the MgO.SiO ₂ -based auxiliary material serpentine as the MgO-based auxiliary material, MgO.CaO
Raw dolomite is a system auxiliary material, also uses dolomitic, MgO concentration of sintered ore is 2-4% by weight, SiO ₂ concentration of 5
Japanese Patent Application Laid-Open No. 53-30403 discloses a method for producing a sintered ore by adjusting the content to 6.5% by mass . Also, "JP 58-39746 discloses" and to "JP 58-39747 discloses" is not used at all the SiO ₂ based auxiliary raw material, sieved MgO · CaO-based auxiliary raw material in classification point of 2mm After that, a method of producing a sintered ore having a SiO ₂ concentration of 4.6 to 5.4 mass % by crushing the under sieve to less than 0.5 mm is disclosed. Further, `` Japanese Patent Laid-Open No. 2-170926
Publication No. 1) proposes a method of producing a sintered ore by using a drum-type vibrating kneader with a built-in cylindrical rod, and crushing and mixing sintering raw materials including light-burned dolomite with one device. Have been.

However, Japanese Unexamined Patent Publication No. Sho 53-30403 discloses
The sintered mineral products obtained by the method described in (1) have a high SiO ₂ concentration of 5 to 6.5% by mass, and it is difficult to increase the sintering ratio in a blast furnace. In the method disclosed in Japanese Patent Application Laid-Open No. 58-39747, an apparatus for crushing the raw material is separately required, and an increase in cost cannot be avoided. And, "Japanese Patent Laid-Open No. 2-
In the method of Japanese Patent No. 170926, even coarse iron ore is crushed, causing difficulty in granulation due to a decrease in the particle size of coarse iron ore that becomes core particles in the granulation process, and Particle size decreases. This reduction in particle size after granulation deteriorates the gas permeability of the sintering raw material-packed layer on the sintering pallet, so that the sintering productivity is reduced, and a reduction in yield is inevitable in order to ensure productivity.

[0007]

As described above, MgO.
Low SiO ₂ sintered ore produced by reducing only the amount of serpentine, which is an SiO ₂ auxiliary material, reduces the yield of sintered mineral products, deteriorates high-temperature properties in the blast furnace, and further increases the viscosity of the blast furnace slag. Has the drawback of causing an increase in On the other hand, in the method using either or both of dolomite and lightly fired dolomite, which are MgO / CaO-based auxiliary materials, dolomite or lightly fired dolomite has poor dispersibility during granulation of the raw material mixture, so MgO / CaO-based auxiliary raw materials remain unreacted, leading to a decrease in yield and high-temperature properties. To prevent this, MgO
Although it is necessary to enhance the dispersibility of CaO-based auxiliary materials, a method of sieving in advance and crushing under the sieve to less than 0.5 mm requires a separate device for crushing the raw materials, resulting in increased costs. . Further, the method using a drum-type vibrating kneader having a built-in cylindrical rod has the disadvantage that even coarse iron ore is crushed, resulting in a decrease in yield.

[0008] An object of the present invention is to improve the dispersibility of dolomite or lightly burned dolomite in a sintering raw material and prevent over-milling of iron ore so as to form appropriate pseudo-particles, thereby making it possible to form appropriate pseudo particles. Low SiO ₂ with good high temperature properties and low slag viscosity generated in blast furnace
An object of the present invention is to provide a method for producing a sintered ore at a high yield.

[0009]

The gist of the present invention resides in the following method for producing a sintered ore.

[The SiO ₂ concentration in the product is 4.0 to 4.8% by mass .
Is a method of producing a sintered ore having an MgO concentration of more than 0.6% by mass, wherein a sintering raw material containing one or both of dolomite and lightly burned dolomite is mixed at a rate of 100 to 500 / min with a mixer having a built-in stirring blade. A method for producing sinter, characterized in that the mixed raw material is used as at least a part of all raw materials after high-speed stirring and mixing at a rotation speed of 100 to 500 rpm . ] In the sintering raw materials mixed by the above-mentioned mixer with a built-in stirring blade, the part having a particle size of 0.5 mm or less is 30% by mass or more (1
00%).

A mixer having a built-in stirring blade used in the method of the present invention is a mixer in which a blade for stirring is installed in a cylindrical pan and both the pan and the blade rotate. As Eirich mixer (trade name)
There is something called. This type of mixer has a blade rotation speed of at least once per minute (1 rpm) or more, and does not have a compaction action, so that sufficient uniform mixing is possible. Therefore, by performing stirring and mixing with this type of mixer, the dispersibility of dolomite and / or lightly fired dolomite in the sintering raw material is improved, and the MgO / CaO-based auxiliary remaining unreacted in the sintered product is improved. Raw materials can be reduced.

After mixing the sintering raw materials with the mixer having the stirring blades as described above, granulation may be further performed using a rolling granulator.

[0013] In the method of the present invention, SiO ₂ in the sintered mineralized product
The concentration is used as a 4.0-4.8% by mass, SiO ₂ concentration of 4.0
Is less than mass% SiO ₂ concentration is too low, because that are not expected to be a sufficient amount of melt produced in the baked Yuika reaction. on the other hand,
The sintered ore that SiO ₂ concentration exceeds 4.8 wt% not be said to be low sinter the SiO ₂ concentration, when charged with the sintered ore in large quantities blast furnace, it hinders the blast furnace operation blast furnace slag ratio increased Will cause. In addition, the reason why the MgO concentration in the sintered ore was set to exceed 0.6% by mass was that, for low SiO ₂ sintered ore with a MgO concentration of 0.6% by mass or less, deterioration of high-temperature properties in the blast furnace and blast furnace This leads to an increase in the viscosity of the slag generated in the above.
The upper limit of the MgO concentration is appropriately about 3% by mass in order to suppress an increase in the amount of blast furnace slag.

In the method of the present invention, “mm” representing the size of a particle means a representative diameter of a sieve, for example, particles having a particle diameter of 0.5 mm or less are measured under a sieve having a sieve of 0.5 mm. In addition, particle size 2
Particles of ~ 1 mm are under a 2 mm sieve and 1 mm
Means particles remaining on the sieve. In addition, the aforementioned “particle size 0.5
The mm particles below contains more than 30 wt% ", when blended with the raw material, which means that the particle size 0.5mm or smaller particles are contained more than 30 wt% in its raw material.

[0015]

Hereinafter, the method of the present invention will be described in detail. In addition, "%" means "% by mass ".

FIG. 1 is a schematic process diagram of an example in which all of the charged raw materials are treated by the method of the present invention. Reference numeral 1 denotes a raw material tank containing sintering raw materials (including auxiliary raw materials); Iron ore, coke breeze, limestone,
It is an Erich mixer that mixes and granulates raw materials by adding water to dolomite, lightly-burned dolomite, and the like.

FIG. 2 is a schematic process diagram of another example of treating the whole charged material by the method of the present invention, in which a drum mixer 3 is used at a stage subsequent to the Eirich mixer 2 shown in FIG.

FIG. 3 is a schematic process diagram of an example of treating a part of the charged raw material by the method of the present invention. The A-based sintered raw material cut out from the raw material tank 1 (a part of the charged raw material is MgO.CaO The raw material obtained by batch-mixing the system auxiliary raw materials) is mixed and granulated by passing through the Erich mixer 2 and then the drum mixer 3A (step of the method of the present invention in FIG. 2). On the other hand, the B-based sintering raw material (the remaining portion of the charged raw material) is obtained by adding a moisture to a separately provided drum mixer 3.
It is mixed and granulated in B. Then, the mixed and granulated materials of the A-based and B-based sintering raw materials are mixed and charged into a sintering pallet.

FIG . 4 is a schematic flow chart of another example of treating a part of the charged material by the method of the present invention.

That is, in the step of the method of the present invention shown in FIG. 2, the A-based sintering raw material is mixed and granulated, and the mixed and granulated material and the B-based sintering raw material are mixed and granulated in the drum mixer 3C. Into the sintering pallet.

The above-mentioned sintering raw materials are stirred and mixed by a mixer (for example, an Erich mixer) having a stirring blade built therein.
This is for the following reason.

[0022] to improve the dispersibility and the reactivity of dolomite or light sintered dolomite is MgO · CaO-based auxiliary raw material,
If the unreacted MgO / CaO-based auxiliary material is reduced, the high-temperature properties of the sinter are improved and the yield increases. However, without excessively crushing iron ore, which accounts for the majority of sinter raw material,
A technique for improving the dispersibility of MgO / CaO-based auxiliary materials has not been known.

The inventors of the present invention disperse a sintering raw material containing one or both of dolomite and lightly burned dolomite and further containing coarse iron ore without excessively crushing the dolomite or lightly burned dolomite. The method of improving the reactivity and reactivity was repeated. As a result, the following was found to be effective.

One or both of dolomite and lightly burnt dolomite are uniformly mixed with other sintering raw materials.

In general, MgO.CaO-based auxiliary materials such as dolomite and lightly burnt dolomite have high tackiness and poor dispersibility, and it is difficult to separate them into particles unless they are mixed by applying a strong mixing force. . Therefore, the MgO concentration
In the case of a sintered ore exceeding 0.6%, the mixing with other sintering raw materials becomes uneven and the particles of the MgO / CaO-based auxiliary raw material aggregate, and the coarseness of the high MgO / high CaO component is substantially increased. This is equivalent to the state in which grains are present, and the reactivity of the MgO / CaO-based auxiliary material is reduced.

The bonding force between particles in the raw material after granulation (hereinafter referred to as “pseudo particles”) is improved.

The pseudo particles having a weak bonding force between the particles have a large amount of peeling off of the adhered powder due to drying. This means that the adhered powder is separated from the pseudo particles due to a rapid temperature rise (rapid drying) during the sintering reaction, and the contact state between the particles is deteriorated when the sintered particles undergo a solid phase reaction. This deterioration of the contact state between the particles impairs the reactivity of dolomite or lightly burned dolomite.

During granulation, the amount of particles that do not become core particles or adhered powder, that is, do not participate in granulation, is reduced.

The particles not involved in granulation are mainly particles having a particle size of 0.25 to 2 mm, that is, particles having an intermediate particle size (Italy Research (1976) No. 288, p. 10). Such particles have a poor contact state with other particles even after granulation, so that the reaction area naturally becomes small. Therefore, if such particles are present in a large amount, the reactivity will decrease.

[0030] The present inventors have found that was investigated ways to achieve the above Symbol ~, to mixing and stirring the sintered material in a mixer with a built-in stirring blade was confirmed to be effective.
A mixer having a built-in stirring blade is a type of mixer in which the blade is installed in a cylindrical pan as described above, and both the pan and the blade rotate, and an Erich mixer is typical. Alternatively, a mixer provided with a rotating stirring blade in a drum mixer can be used.

When stirring is performed using a mixer having a built-in stirring blade, the strong mixing force causes even the MgO / CaO-based auxiliary material having high tackiness and poor dispersibility to be converted from the agglomerated state to the particle unit. Separated and uniformly mixed in the sintering raw material,
The uneven distribution of MgO / CaO-based auxiliary material is eliminated. That is, the above condition can be satisfied.

By the strong mixing force of the mixer having a built-in stirring blade, the water added at the time of mixing permeates the entire raw material, and a water film is formed on the surface of all the particles regardless of the particle diameter of the sintering raw material. And the plasticity of the particles is improved. As a result, the adhesion of the fine powder functioning as the adhesion powder during granulation is increased, and the bonding force between the particles constituting the pseudo particles is increased. This satisfies the above condition.

Further, water droplets are made fine by strong mixing force, and the water droplets facilitate the formation of a water film on the particle surface of the sintering raw material. Therefore, a particle size of 0.25 to 2 which is hardly involved in granulation by a normal granulation method (for example, using a drum mixer).
mm particles are plasticized and adhere to other particles and become involved in granulation. This satisfies the above condition.

In order to secure a strong mixing force for obtaining the above effects, the rotation speed of the stirring blade is set to 100 times per minute (100 rpm).
Above. The upper limit of the rotation speed is 500 times per minute (500r
pm) is appropriate . In addition, since the mixer incorporating the stirring blade has no compaction action, the iron ore particles themselves are not crushed. Therefore, the coarse iron ore serving as the nucleus of the pseudo particles is not excessively pulverized into fine particles, and the formation of pseudo particles due to the reduction of the core particles does not occur.

Note that not only the blades but also the pan (or drum) may be rotated. There is no particular limitation on the rotation direction and rotation speed.

When a tumbling type granulator is used after a mixer having a stirring blade built therein, it is desirable to add most of the water at the stage of using the mixer having the stirring blade built therein. This is because the addition of moisture under strong mixing conditions improves the plasticity of the particles and has the effect of increasing the interparticle bonding force of the pseudo particles.

In the sintering raw material mixed by the mixer having the high-speed stirring blade therein, it is desirable that the portion having a particle size of 0.5 mm or less is 30% or more. As described above, the coarse iron ore is mixed and dispersed in the raw material without being crushed as described above, and the number of particles having a particle diameter serving as adhered powder increases. Quasi-particles can be formed stably. For this reason, the effect of dispersion and granulation by the mixer incorporating the stirring blade is further improved.

[0038]

Example 1 A sintering raw material was granulated by the method of the present invention using a mixer having a built-in stirring blade, and the effect of suppressing the collapse of the pseudo particles by drying and the amount of particles not involved in the granulation were determined. The effect of reducing, that is, the effect of involving intermediate-size particles in granulation was investigated.

Table 1 shows the raw material conditions and the granulation method, and Table 2 shows the specifications (operating conditions) of the granulator used. In addition,
-0.5 mm representing the particle size in Table 1 and the table below is
It means particles having a particle size of 0.5 mm or less.

(A) Disintegration of pseudo particles by drying The mass ratio of particle size of 2 mm or less in the following pseudo particle size distribution survey b and the particle size in the following pseudo particle size distribution survey a
Evaluation was made based on the difference from the mass ratio of 2 mm or less (hereinafter, referred to as “dry disintegration amount (% by mass )”). The smaller the difference, the less the pseudo-particles collapse due to drying, and the better the permeability of the raw material packed layer during sintering.

[Pseudo-grain size distribution investigation a] The raw material after granulation is divided into units of 450 g to 500 g and then sieved with a hand sieve in a wet state.

[Pseudo-grain size distribution survey b] The raw material after the pseudo-grain size distribution survey a is dried at 110 ° C for 2 hours and then sieved.

(B) Involvement of Intermediate Particle Size Particles in Granulation From the results of the following particle size distribution investigation of the particles constituting the pseudo particles (by pseudo particle size, that is, by pseudo particles having different particle sizes), 2-1 mm, 1-0.5 mm and 0.5-0.25 mm particles
Analyzing how much each particle contained in the pseudo particle, that is, the distribution state in the pseudo particle,
The contribution of these particles to granulation was evaluated.

[Survey of Particle Size Distribution of Particles Constituting Pseudo Particles (Pseudo Particle Size Distribution)] The pseudo particle size raw materials after the pseudo particle size distribution survey b are performed are decomposed into constituent particle units by washing with water and sieved.

FIG. 5 shows the results of a study on the drying and disintegration of the pseudo particles. The case 1 using the Erich mixer of the present invention and the case 2 provided with a drum mixer at the subsequent stage of the Erich mixer were both drums. The amount of dry disintegration is almost halved compared to the comparative example using only the mixer. From this result, it is understood that pseudo particles having a strong interparticle bonding force are formed by the method of the present invention.

FIG. 6 shows the results of an investigation on the involvement of intermediate-size particles in granulation. The results show that intermediate-size particles having a particle size of 0.25 to 0.5 mm, 0.5 to 1 mm, and 1 to 2 mm (here, FIG. 4 is a diagram showing the distribution of constituent particles in pseudo particles. The horizontal axis represents the particle size range of the pseudo-particles.
(0.5 mm), "0.5 -1" means that the raw material after granulation was sieved with a hand sieve in a wet state, then dried at 110 ° C, and then sieved again. Represents The abundance ratio of the constituent particles on the vertical axis is 0.5
This means the abundance ratio of particles having a particle size of 0.25 to 0.5 mm in which 擬 似 1 mm pseudo particles are decomposed into constituent particle units by washing with water and sieved.

In FIG. 6, the solid line is Case 2 of the present invention, the broken line is the conventional example, and □ and Δ are the ratios when the particle size of the constituent particles matches the particle size of the pseudo particles. Are present alone and are not involved in the granulation, the symbols △ and ▲ indicate the ratio of the constituent particles in the pseudo-particles having a rank larger than that of the constituent particles. In the case of functioning as particles, ○ and ● marks indicate the ratio of the constituent particles present in pseudo particles having a diameter of at least two ranks larger than that of the case where the constituent particles function as adhered powder in granulation. is there.

As can be seen from the results shown in FIG. 6, when the Erich mixer was used (Example 2 of the present invention), the ratio of the constituent particles as they were was significantly reduced as compared with the case where the Erich mixer was not used (Comparative Example). And the symbol ■), the constituent particles are 0.25 to 0.
In the case of 5 mm, the one that functions as an adhering powder increases,
In the case of 1 mm and 1 to 2 mm, it can be seen that those that function as nuclear particles are increasing. From these results, it can be seen that the method of the present invention has a particle size that is not considered to be involved in granulation in the conventional method.
Raw material particles of 0.25 to 2 mm can contribute to granulation,
It can be seen that pseudo particles are formed stably.

[0049]

[Table 1]

[0050]

[Table 2]

[0051]

Example 2 A sintering pot test was performed on the sintering raw materials having the composition of A-1, A-2, B and C shown in Table 3 by applying the method of the present invention, and the product yield of sinter ore and The improvement effect of high temperature properties was investigated.

The granulator used was Example 1 shown in Table 2 above.
The granulation method is the same as shown in Table 4 below. Table 5 shows combinations of the raw materials and the granulation method.

In the firing, the raw material after granulation is charged into a cylindrical pot having a diameter of 300 mm, the bed height is 500 mm, and the superficial air velocity is 15.0 Nm ³ / m
^The test was performed under constant conditions for ² min. The reason why the air tower wind speed is constant is that the firing time, which has a large effect on the sinter quality, is constant. That is, the yield and quality of the sintered ore were evaluated with the heat pattern of sintering being a constant condition. In addition,
The ignition conditions were LPG 90 liters / minute for 2 minutes, and the firing was completed 90 seconds after BTP (Burn through point, maximum point of exhaust gas temperature).

The load softening test of the sintered ore is 0 to 9.8 × 10-2 kg
At a load of f / mm ^2, the temperature was raised in a mixed gas atmosphere of CO / N ₂ = 0 to 1, and the shrinkage ratio and pressure loss of the sample during the heating process were measured. Then, high-temperature properties were evaluated based on the integrated value of the pressure loss.
Generally, when the charge begins to unload and soften in the blast furnace,
It is considered that the higher the softening / melting temperature and the narrower the temperature range between the softening start temperature and the burn-through temperature, the better the properties of the charge. Therefore, the lower the integrated value of the pressure loss, the better the high-temperature property is evaluated.

FIG. 7 shows the results of the investigation. As shown in the figure, when only a drum mixer is used as in the case of the granulation e method and dolomite having high adhesiveness, poor dispersibility and low reactivity, and dolomite lightly burned are mixed to produce a low SiO ₂ sintered ore, Stay 70
%, The pressure drop integrated value is 550 mH ₂ O or more, and the high temperature properties are not good (conventional cases 13, 14).

On the other hand, in each of the examples to which the method of the present invention was applied, the product yield was 85% or more, and the pressure loss integrated value was 500 mH.
_{At 2} O or less, both the yield and high temperature properties are improved.
In particular, in the cases 7 and 8 of Example 2 of the present invention of the granulation b method using the Erich mixer and the drum mixer together, the improvement effect is high. In addition, Example 3 of the present invention was prepared by mixing MgO / CaO-based auxiliary raw materials in the A-based raw materials at one time, using the Erich-mixer and the drum mixer together for the A-based raw materials, and granulating the B-based raw materials using only the drum mixer. , 4 (granulation c method, d
Method), a sufficient improvement effect has been obtained. Since the effect was also obtained in Example 1 of the present invention (granulation a method) using the Erich mixer alone, MgO / CaO
It is considered that the dispersibility and reactivity of the system auxiliary material were improved, and pseudo particles having strong inter-particle bonds were stably formed.

From the above results, it can be seen that the method of the present invention enables the production of sintered ores with good low-temperature properties and high SiO ₂ concentration at a high yield.

[0058]

[Table 3]

[0059]

[Table 4]

[0060]

[Table 5]

[0061]

According to the method of the present invention, a low SiO ₂ sintered ore having a good high-temperature property in a blast furnace and a low slag viscosity generated in the blast furnace can be produced at a high yield. be able to. By using the low SiO ₂ sintered ore obtained in the method of the present invention, a stable operation of the blast furnace becomes possible even if the mixing ratio of the sintered ore is increased, and it is possible to sufficiently cope with the depletion of the raw material of the high quality lump ore.

[Brief description of the drawings]

FIG. 1 is a diagram showing an example of a schematic process for treating all of a charged material by a method of the present invention.

FIG. 2 is a diagram showing schematic steps of another example in which all of the charged materials are treated by the method of the present invention.

FIG. 3 is a schematic view showing an example of a schematic process of treating a part of a charged material by the method of the present invention.

FIG. 4 is a diagram showing schematic steps of another example of treating a part of the charged material by the method of the present invention.

FIG. 5 is a graph showing the effect of the method of the present invention for suppressing dry disintegration of pseudo particles.

FIG. 6 is a diagram showing the effect of the method of the present invention on the involvement of intermediate-size particles in granulation.

FIG. 7 is a diagram showing the effects of the method of the present invention on the product yield and high-temperature properties of sintered ore.

[Explanation of symbols]

1: raw material layer, 2: Erich mixer, 3,3A, 3B, 3
C: Drum mixer

Continuation of front page (58) Field surveyed (Int. Cl. ⁷ , DB name) C22B 1/00-61/00

Claims (2)

(57) [Claims] (1) When the SiO ₂ concentration in the product is 4.0 to 4.8% by mass .
A method for producing sintered ore with an MgO concentration of more than 0.6% by mass. A sintering raw material containing one or both of dolomite and lightly burned dolomite is mixed by a mixer with a built-in stirring blade.
After high-speed stirring and mixing at a rotation speed of 100 to 500 times per minute ,
A method for producing a sintered ore, wherein the mixed raw material is used as at least a part of all raw materials used. 2. The production of sintered ore according to claim 1, wherein the sintering raw material to be mixed by the mixer having a stirring blade is 30 mass % or more in a portion having a particle diameter of 0.5 mm or less. Method.