WO2024157572A1 - Sintered ore production method - Google Patents

Abstract

Provided is a sintered ore production method with which it is possible to maintain productivity in the production of sintered ore even when the sintering raw material contains Marra Mamba ore as an alternative to pisolite ore.　This sintered ore production method produces sintered ore from a sintering raw material that contains whole iron ore, and includes, in the whole iron ore, 30.0 mass% or more of an iron ore having an iron content of 58.0 mass% or more, a water of crystallization content of at least 4.00 mass% but less than 9.00 mass%, an Al₂O₃ content of 2.00 mass% or more, and an SiO₂ content of less than 5.0 mass%, wherein the blend of the sintering raw material is adjusted so that the SiO₂ content of the sintered ore is 5.50-6.00 mass% and the CaO content is 11.0-12.0 mass%.

Description

Sinter manufacturing method

The present invention relates to a method for producing sintered ore from sintered raw materials containing iron ore.

Sintered ore, the raw material used in the blast furnace iron-making process, is produced by sintering raw materials that include powdered iron ore, auxiliary materials such as limestone, and carbonaceous materials such as coke. There are many different brands of iron ore with different compositions and particle sizes, and multiple brands of iron ore are blended together to produce the sintered raw material.

The iron ore used in Japan is broadly divided into hematite ore and magnetite ore from South America, and hematite ore, pisolite ore, and Marra Mamba ore from Australia. South American ore is high in Fe content and high quality, but its origin is remote, which creates a problem in terms of transportation costs. The production of Australian ore has increased significantly since the 1980s, and it has been used as the main raw material for iron ore in Japan. Since the 2000s, as Australian hematite ore has been depleted, the use of Australian pisolite ore has expanded. Since then, Australian pisolite ore has been widely used as iron ore in Japan. In recent years, Australian pisolite ore has also been depleted, and Marra Mamba ore has been attracting attention as the main iron ore of the future. It is expected that Australian pisolite ore used in Japan will be replaced by Marra Mamba ore in the future. The properties and compositions of various iron ores are shown in Table 1.

As shown in Table 1, Marra Mamba ore has a higher content of fines with diameters of 0.15 mm or less than pisolite ore. Marra Mamba ore has a higher alumina content ( _Al2O3 content) and a lower silica content ( _SiO2 content) than pisolite ore. In light of this, in order to deal with the _increase in fine content caused by the use of Marra Mamba ore, development has been carried out to improve the permeability of the sintering raw material during the sintering process when using Marra Mamba ore as the sintering raw material.

Patent Document 1 discloses a method for preventing problems caused by the particle size of Marra Mamba ore by limiting the blending rate of Marra Mamba ore to 70% or less of the total iron ore. According to Patent Document 1, by limiting the blending rate of Marra Mamba ore, the proportion of fine ore with a particle size of 0.25 mm or less can be restricted, thereby suppressing the impact on productivity.

Patent Document 2 discloses a method for producing sintered ore in which the blending ratio of Brazilian pellet feed is reduced by 30% or more relative to the increase in the blending ratio of Marra Mamba ore relative to the blending ratio of the standard sintered raw materials when Marra Mamba ore is not used, based on the blending ratio of sintered raw materials. According to Patent Document 2, when using Marra Mamba ore, reducing the blending ratio of Brazilian pellet feed, which has poor granulation properties, improves granulation properties and maintains good product yield, sintered ore quality, and productivity.

Patent Document 3 discloses a method for producing sintered ore by adding pisolite ore to Marra Mamba ore, mixing and granulating the mixture with 3.0 to 5.0% by mass of _SiO2 and less than 30% by mass of fine powder of 0.5 mm or less, adding 5 to 10% by mass of water, and adding solid fuel and other ores, mixing and granulating again, and then sintering. By adding porous pisolite ore to Marra Mamba ore, adding an appropriate amount of water, and mixing and granulating with a high-speed stirring mixer, some of the fine powder of Marra Mamba ore adheres to the open pores of the pisolite ore, and a mixed granulated product with less fine powder is obtained. It is disclosed that as a result, the pseudo particle size and pseudo particle strength are improved, and the air permeability during the sintering process is improved, thereby improving the production rate and product yield.

Patent No. 5004421 Patent No. 4786022 JP 2004-137575 A

Marra Mamba ore has a lower SiO ₂ content, a higher Al ₂ O ₃ content, and a higher fine powder content than pisolite ore. In addition, in a blast furnace process in which sintered ore is used, it is necessary to control the basicity of the slag produced, so the basicity of the sintered ore must also be kept within a certain range. For this reason, in the sintering raw material, the CaO content also decreases with a decrease in SiO ₂ content. Therefore, as the replacement of pisolite ore with Marra Mamba ore progresses, the SiO ₂ content and CaO content in the sintering raw material decrease, and the Al ₂ O ₃ content and fine powder content increase. In addition, if the fine powder content increases, the air permeability of the sintering raw material in the sintering process decreases, leading to a decrease in the sintering speed and a decrease in the productivity. For this reason, as disclosed in Patent Documents 1 to 3, methods have been developed to obtain good air permeability and productivity using Marra Mamba ore by strengthening granulation and limiting the amount of Marra Mamba ore used.

On the other hand, Patent Documents 1 to 3 do not consider the influence of the difference in chemical composition between Marra Mamba ore and pisolite ore on the sintering process and sintered ore. In particular, when using Marra Mamba ore, there is no consideration of what the _SiO2 content, _CaO content, and _Al2O3 content should be to obtain high-strength sintered ore with good productivity.

The present invention was made in consideration of these circumstances, and aims to provide a method for producing sintered ore that can maintain the productivity rate in sintered ore production even when Marra Mamba ore is included in the sintering raw material as a substitute for pisolite ore.

The gist and configuration of the present invention to solve the above problems are as follows.
[1] A method for producing sintered ore, which comprises making the total iron ore contain 30.0% by mass or more of iron ore having an iron content of 58.0% by mass or more, a crystal water content of 4.00% by mass or more but less than 9.00% by mass, an Al ₂ O ₃ content of 2.00% by mass or more, and _a SiO 2 content of less than 5.0% by mass, and producing sintered ore from a sintering raw material containing the total iron ore, and adjusting the composition of the sintering raw material so that the SiO ₂ content of the sintered ore is 5.50 to 6.00% by mass and the CaO content is 11.0 to 12.0% by mass.
[2] The method for producing sintered ore described in [1], wherein the composition of the sintering raw materials is adjusted so that silica stone is contained in the sintering raw materials.
[3] The method for producing sintered ore according to [1] or [2], wherein the composition of the sintering raw materials is adjusted so that the Al ₂ O ₃ content of the sintered ore is 1.9 mass% or less.
[4] The method for producing sintered ore according to [3], wherein the composition of the sintering raw materials is adjusted so that the iron ore contains 5.0 mass% or more of iron ore having an iron content of 64.0 mass% or more, a crystal water content of less than 1.00 mass%, and _{an Al2O3} content of less than 0.50 mass% in the total iron ore.
[5] In the adjustment of the composition of the sintering raw materials, the iron ore having an iron content of 60.0 mass% or more, a crystal water content of less than 4.00 mass%, _{an Al2O3} content of less than 1.50 mass%, and a _SiO2 content of 4.5 mass% or more and less than 5.0 mass% is adjusted so that the total iron ore contains 55.0 mass% or more of iron ore.
[6] The method for producing sintered ore described in [5], wherein the composition of the sintering raw material is adjusted so that the proportion of particles smaller than 0.5 mm in the total iron ore is 40.0 mass% or less.

According to the present invention, the productivity rate in the production of sintered ore can be maintained even when Marra Mamba ore is included in the sintering raw material as a substitute for pisolite ore.

FIG. 1 shows the results of productivity, yield and sintering rate in Tests 1 and 2. FIG. 2 shows the results of productivity, yield and sintering rate in Tests 3 and 4. FIG. 3 shows the results of productivity, yield and sintering rate in Tests 5 and 6. FIG. 4 shows the results of productivity, yield, sintering rate and strength in Tests 3, 4, 7 and 8.

The present invention will be explained below through an embodiment of the present invention.

In this embodiment, Marra Mamba ore is used as a substitute for pisolite ore, which has traditionally been used as the iron ore contained in the sintering raw material used to manufacture sintered ore. The amount of Marra Mamba ore contained in the sintering raw material is 30.0% by mass or more, which is sufficient to replace pisolite ore.

Table 2 explains the content of each component, fine powder content, and water of crystallization for Marra Mamba ore used in the production of sintered ore. Table 2 also shows the content of each component, fine powder content, and water of crystallization content for various iron ores used in the production of sintered ore.

As shown in Table 2, Marra Mamba ore has a composition with an iron content (T.Fe) of 58.0 mass% or more, _{an Al2O3} content of 2.00 mass% or more, and a _SiO2 content of less than 5.0 mass%. The water of crystallization (LOI) content of Marra Mamba ore is 4.00 mass% or more and less than 9.00 mass%.

The sintering raw material is adjusted so that the total iron ore containing 30.0% or more by mass of Marra Mamba ore is included in the sintering raw material, and the composition of the sintered ore after sintering is such that the _SiO2 content is 5.50 to 6.00% by mass and the CaO content is 11.0 to 12.0% by mass. Specifically, the sintering raw material is adjusted so that an auxiliary material with a high _SiO2 content is included in the sintering raw material, or an auxiliary material with a high _SiO2 content is included in the sintering raw material and iron ore with a higher _SiO2 content than Marra Mamba ore or pisolite ore is used in combination with Marra Mamba ore.

As iron ore having a higher _SiO2 content than Marra Mamba ore or pisolite ore, for example, ore F having a higher _SiO2 content may be used among the various iron ores shown in Table 2. Also, as an auxiliary material having a higher _SiO2 content, for example, silica stone or the like may be used. That is, in adjusting the sintering raw material, silica stone or the like having a higher _SiO2 content may be included as an auxiliary material in the sintering raw material, or an auxiliary material having a higher _SiO2 content may be included in the sintering raw material and an ore having a higher _SiO2 content than Marra Mamba ore or pisolite ore may be used in combination with the Marra Mamba ore.

This makes it possible to compensate for the decrease in the _SiO2 content of the sintering raw material caused by the use of Marra Mamba ore, so that the basicity can be kept constant without decreasing the CaO content, and the decrease in the CaO content is suppressed. As a result, sufficient molten liquid is generated in the sintering raw material during sintering, the decrease in the sintered ore yield is suppressed, and a good productivity of 1.5 t/h ^m2 or more can be obtained.

In addition, regarding the composition of the sintered ore, the sintering raw material may be adjusted so that the SiO ₂ content is 5.50 to 6.00 mass% and the CaO content is 11.0 to 12.0 mass%, and then the composition of the sintering raw material may be further adjusted so that the Al ₂ O ₃ content is 1.9 mass% or less.

Specifically, in adjusting the sintering raw material, iron ore having a lower _Al2O3 content than Marra Mamba ore or pisolite ore may be used in combination with Marra Mamba ore. In this case, the iron ore having a lower _Al2O3 content than _{Marra Mamba} ore or pisolite ore may be further adjusted so that it contains 5.0 mass% or more of the iron ore in total.

As iron ore having a lower Al ₂ O ₃ content than Marra Mamba ore or pisolite ore and usable in combination with Marra Mamba ore, for example, low alumina fine ore G having a lower Al ₂ O ₃ content may be used among various iron ores shown in Table 2. That is, in adjusting the sintering raw material, low alumina fine ore G having a lower Al ₂ O ₃ content than Marra Mamba ore or pisolite ore may be used in combination with Marra Mamba ore. And, low alumina fine ore G having a lower Al ₂ O ₃ content than Marra Mamba ore or pisolite ore may be further adjusted so that it contains 5.0 mass% or more of low alumina fine ore G in the total iron ore. As shown in Table 2, the composition of low alumina fine ore G is 64.0 mass% or more of iron, less than 1.00 mass% of water of crystallization, and less than 0.50 mass% of Al ₂ O ₃ .

In addition, in adjusting the sintering raw material, the blending ratio of iron ore having a lower Al ₂ O ₃ content than Marra Mamba ore or pisolite ore in the total iron ore may be increased. In this case, the iron ore having a lower Al ₂ O ₃ content than Marra Mamba ore or pisolite ore may be adjusted to contain 55.0 mass% or more of the iron ore in the total iron ore.

As an iron ore having a lower Al ₂ O ₃ content than Marra Mamba ore or pisolite ore and capable of increasing the blending ratio in the total iron ore, for example, among various iron ores shown in Table 2, ore E having a lower Al ₂ O ₃ content may be used. That is, in adjusting the sintering raw material, ore E having a lower Al ₂ O ₃ content than Marra Mamba ore or pisolite ore may be increased in the blending ratio in the total iron ore. And, ore E having a lower Al ₂ O ₃ content than Marra Mamba ore or pisolite ore may be further adjusted to contain 55.0 mass% or more in the total iron ore. As shown in Table 2, the composition of ore E is 60.0 mass% or more of iron, less than 4.00 mass% of crystal water, less than 1.50 mass% of Al ₂ O ₃ , and 4.5 mass% or more and less than 5.0 mass% of SiO ₂ .

In this way, by using or increasing the amount of _iron ore with a lower _Al2O3 content than Marra _Mamba ore or pisolite ore, the increase in _Al2O3 content of the sintering raw material due to the use of Marra Mamba ore can be suppressed. As a result, the increase in the melting point of the molten liquid generated in the sintering raw material during sintering is suppressed, the fluidity of the sintering raw material is increased, the coalescence of solid particles is promoted, and the strength of the sintered ore is improved. Specifically, the shutter strength of the sintered ore can be increased to 75% or more.

In addition, the composition of the sintered ore may be adjusted so that the _SiO2 content is 5.50 to 6.00 mass%, the CaO content is 11.0 to 12.0 mass%, and _{the Al2O3} content is 1.9 mass% or less, and the total iron ore in the sintered raw material may be adjusted so that the proportion of particles smaller than 0.5 mm in the total iron ore is 40.0 mass% or less.

In this way, by adjusting the ratio of particles smaller than 0.5 mm in the total iron ore in the sintering raw material to 40.0 mass % or less, the air permeability of the sintering raw material layer during sintering is improved, and the sintering process is accelerated, thereby further improving the productivity of sintered ore. Specifically, the productivity of sintered ore can be increased to 1.7 t/(h·m ² ) or more.

Below, we will explain examples that were carried out using the sintered ore manufacturing method according to this embodiment.

Several percent of water was added to the sintering raw material, which included various iron ores, auxiliary materials including limestone or silica, and carbonaceous materials such as coke, and the sintering raw material was mixed and granulated to obtain pseudo-granulated sintering raw material. A sintering test was conducted on the pseudo-granulated sintering raw material using a cylindrical sintering test pot with a diameter of 300 mm and a height of 400 mm. 20 mm of sintered ore was packed as a floor on the fire grate inside the cylindrical sintering test pot, and the pseudo-granulated sintering raw material was packed on top of that as a sintering raw material layer. The carbonaceous material contained in the top of the packed sintering raw material layer was ignited, and the combustion of the carbonaceous material progressed downward while air was sucked downward, and the sintering raw material layer was sintered by the combustion heat of the carbonaceous material to obtain a sintered cake.

In the examples, the time required from the start of sintering until the temperature of the combustion exhaust gas reached its maximum value was taken as the sintering time. The height of the cylindrical sintering test pot was divided by the sintering time to obtain the sintering speed (mm/min). After the completion of sintering, the sintered cake was taken out of the cylindrical sintering test pot and dropped four times from a height of 2 m, after which the weight of the sintered cake on the 5 mm sieve was weighed, and the ratio of the weight of the sintered cake on the 5 mm sieve to the weight of the sintered cake before dropping was taken as the yield (mass%). The weight of the sintered cake on the 5 mm sieve obtained was divided by the sintering time and the bottom area of the test pot to obtain the productivity (t/(h·m ² )). The strength (%) of the sintered ore was measured based on the drop strength index (SI) of "JIS M8711 Iron ore sinter - Drop strength test method". The sintered raw materials subjected to the sintering test are shown in Table 3.

The sintering tests were conducted using a total of eight sintering raw materials, as shown in Table 3, for Tests 1 to 3 and Test 5, which are comparative examples, and Tests 4, 6 to 8, which are invention examples. The sintering raw materials were adjusted based on the raw material blending ratios shown in Table 3 so that the sintered ore composition after sintering would be as shown in Table 3. The sintering raw materials were then mixed, humidified, and granulated to form pseudo-granules, which were then filled into the sintering raw material layer and sintered using the heat of combustion of the carbonaceous material to produce sintered ore. The sintering raw materials for Tests 1 to 8 were sintered by sucking air from below the sintering raw material layer based on the suction pressure (kPa) shown in Table 3.

<Example 1> Figure 1 shows the results of Test 1 and Test 2, which are comparative examples. Test 1 is a comparative example in which pisolite ore was used as the iron ore in the sintering raw material. In Test 2, Marra Mamba ore was used as the iron ore in the sintering raw material. In other words, Test 2 is a comparative example in which Marra Mamba ore was used as a substitute for the pisolite ore in Test 1.

As shown in Table 3, the SiO ₂ content in Test 2 was 5.27% by mass compared to the SiO ₂ content (5.99% by mass) in Test 1. Also, the CaO content in Test 2 was 9.9% by mass compared to the CaO content (11.4% by mass) in Test 1. Accordingly, as shown in FIG. 1, the yield and productivity in Test 2 were lower than those in Test 1. Specifically, the productivity in Test 2 was 1.28 t/(h·m ² ) compared to the productivity in Test 1 (1.36 t/(h·m ² )). This is because the yield was lowered due to the reduced SiO ₂ and CaO contents in the sintering raw material, and the amount of molten liquid generated during sintering was reduced.

<Example 2> Next, the results of Test 3, which is a comparative example, and Test 4, which is an example of the invention, are shown in FIG. 2. Test 3 shows the results of using pisolite ore as the iron ore in the sintering raw material. Test 4 shows the results of using Marra Mamba ore as the iron ore in the sintering raw material. In Test 4, in order to suppress the decrease in the SiO ₂ content in the sintering raw material due to the use of Marra Mamba ore, silica stone with a high SiO ₂ content was further included in the sintering raw material as an auxiliary material. That is, Test 4 is an example of the invention in which Marra Mamba ore was used as the iron ore in the sintering raw material, and the sintering raw material was adjusted so that the composition of the sintered ore after sintering was 5.80 mass% SiO ₂ and 11.0 mass% CaO. Test 3 was conducted under the same conditions as Test 4, except for the adjustment regarding the use of Marra Mamba ore and silica stone in Test 4.

As shown in Table 3, the _SiO2 content in Test 4 was 5.80 mass% compared to the _SiO2 content (5.80 mass%) in Test 3. Also, the CaO content in Test 4 was 11.0 mass% compared to the CaO content (11.0 mass%) in Test 3. As a result, as shown in FIG. 2, in Test 4, a good productivity of 1.62 t/(h· ^m2 ) was obtained without causing a decrease in yield as confirmed in the implementation result of Test 2, compared to Test 3.

<Example 3> Next, the results of Test 5, which is a comparative example, and Test 6, which is an example of the invention, are shown in FIG. 3. Test 5 shows the results of using pisolite ore as the iron ore in the sintering raw material. Test 6 shows the results of using Marra Mamba ore as the iron ore in the sintering raw material. Test 6 shows the results of using silica stone with a high SiO ₂ content as an auxiliary raw material in the sintering raw material in order to suppress the decrease in SiO ₂ content in the sintering raw material due to the use of Marra Mamba ore, and also shows the results of using ore F with a high SiO ₂ content (see Table 2) in combination with Marra Mamba ore. That is, Test 6 is an example of the invention in which Marra Mamba ore is used as the iron ore in the sintering raw material, and the sintering raw material is adjusted so that SiO ₂ is 5.59 mass% and CaO is 11.2 mass% in the composition of the sintered ore after sintering. Test 5 shows the results of a test conducted under the same conditions as Test 6, except for the adjustments regarding the use of Marra Mamba ore, silica stone, and ore F in Test 6.

As shown in Table 3, the _SiO2 content in Test 6 was 5.59 mass% compared to the _SiO2 content (5.60 mass%) in Test 5. Also, the CaO content in Test 6 was 11.2 mass% compared to the CaO content (11.2 mass%) in Test 5. As a result, as shown in Figure 3, Test 6 achieved a good productivity of 1.54 t/(h· ^m2 ) without causing a decrease in yield compared to Test 5.

<Example 4> Figure 4 shows the results of Test 3, Test 4, and Tests 7 and 8, which are examples of the invention, regarding the strength of sintered ore (shutter strength, hereafter simply referred to as "strength"). In Figure 4, Tests 3 and 4 were conducted using the same sintered raw materials as Tests 3 and 4 shown in Figure 2.

As shown in Fig. 4, the strength of the sintered ore in Test 4 was 71.2%, which was lower than the strength of the sintered ore in Test 3 (74.4%) in which _{pisolite ore was used as the iron ore. This is because the Al2O3 content} in Test 4 (2.06% by mass) was higher than the _Al2O3 content in Test _{3 (1.91% by mass). In other words, as a result of the increase in the Al2O3 content in} the sintering raw material, the melting point of the molten liquid generated in the sintering process increased, the fluidity decreased, and the coalescence of solid particles was inhibited, resulting in a decrease in strength. For this reason, it can be seen that it is preferable to limit the _Al2O3 content in order to obtain high-strength sintered ore while using Marra _Mamba ore as the iron ore contained in the sintering raw material.

In Test 7, in order to suppress an increase in _{the Al2O3} content in the sintering raw material due to the use of Marra Mamba ore, low- _alumina fine ore G (see Table 2) with a low _Al2O3 content was used in combination with Marra Mamba ore. In other words, Test 7 is an example of the invention in which Marra Mamba ore was used as the iron ore in the sintering raw material, silica was also used as an auxiliary raw material, and the sintering raw material was adjusted so that the composition of the sintered ore after sintering was 5.80 mass% _SiO2 , 11.0 mass% CaO, and 1.90 mass% _{Al2O3 .}

In Test 8, in order to suppress the increase in _{the Al2O3} content in the sintering raw material due to the use of Marra Mamba ore, the amount of Ore E (see Table 2), which has a low _Al2O3 content _, mixed in the sintering raw material was increased. That is, Test 8 is an example of the invention in which Marra Mamba ore was used as the iron ore in the sintering raw material, and silica was also used as an auxiliary raw material, and the sintering raw material was adjusted so that the composition of the sintered ore after sintering was 5.80 mass% _SiO2 , 11.0 mass% CaO, and _1.88 mass% _Al2O3 .

In Figure 4, Tests 7 and 8 show the results of tests conducted under the same conditions as Tests 3 and 4, except for the use of low alumina fine ore G in Test 7 and the adjustment of the increased amount of ore E in Test 8. As shown in Figure 4, Tests 7 and 8 produced good results, with the strength of the sintered ore at 75% or more. Tests 7 and 8 also produced good results, with the yield at 75% or more.

In particular, in Test 7, a high strength of 80% or more was obtained. This is because the sintering rate decreased due to the influence of the air permeability inhibition in the sintering raw material layer caused by the fine ore powder, in addition to the restriction of _{the Al2O3} content. In Test 8, a good result of 75% or more strength was obtained. This is because the restriction of _{the Al2O3} content suppressed the rise in the melting point of the molten liquid generated during sintering, and strong particle bonding was obtained, resulting in improved strength of the sintered ore.

As shown in Figure 4, the sintering speed in Test 7 was slower than in Tests 3 and 4, which were conducted under similar conditions. This is because the proportion of particles smaller than 0.5 mm (hereinafter also referred to as "fine powder") in the iron ore in Test 7 was high, at 40 mass% or more (see Table 3). In other words, when the proportion of fine powder in the total iron ore in the sintering raw material is 40 mass% or more, the air permeability during sintering is significantly reduced, and the sintering speed is reduced. From this result, it can be seen that it is preferable to adjust the proportion of fine powder in the total iron ore in the sintering raw material to less than 40 mass%. This improves air permeability during sintering, and high-strength sintered ore can be obtained at a high productivity rate.

Therefore, as shown in Table 3, in Test 8, the ratio of fine powder to the total iron ore in the sintering raw material was adjusted to be less than 40 mass%. As a result, the sintering speed in Test 8 was faster than that in Test 7. In Test 8, the Al ₂ O ₃ content was 1.90 mass% or less, so the strength of the sintered ore was also good. In addition, in Test 8, the SiO ₂ content was 5.80 mass% and the CaO content was 11.0 mass%, so the yield was also good. Then, the amount of melt in the sintering raw material layer increased during sintering, and strong bonding of solid particles was obtained. In addition, the amount of fine powder in the total iron ore was reduced, and the sintering speed was increased. As a result, high-strength sintered ore could be obtained at a good sintering speed, and the productivity was greatly improved. Specifically, in Test 8, high-strength sintered ore of 75% or more could be obtained at a high productivity of 1.7 t/(h·m ² ) or more.

Claims (6)

A method for producing sintered ore, comprising the steps of: making the total iron ore contain 30.0% by mass or more of iron ore having an iron content of 58.0% by mass or more, a crystal water content of 4.00% by mass or more but less than 9.00% by mass, an _Al2O3 content of 2.00% by mass or more, and _{a SiO2} content of less than 5.0% by mass; and producing sintered ore from a sintering raw material containing the total iron ore,
A method for producing sintered ore, comprising adjusting the composition of the sintering raw material so that the _SiO2 content of the sintered ore is 5.50 to 6.00 mass% and the CaO content is 11.0 to 12.0 mass%. The method for producing sintered ore according to claim 1, wherein the composition of the sintering raw materials is adjusted so that silica is included in the sintering raw materials. The method for producing sintered ore according to claim 1 or 2, wherein the composition of the sintering raw materials is adjusted so that the Al ₂ O ₃ content of the sintered ore is 1.9 mass % or less. The method for producing sintered ore according to claim ₃ , wherein the composition of the sintering raw materials is adjusted so that the iron ore contains 5.0 mass% or more of iron ore having an iron content of 64.0 mass% or more, a crystal water content of less than 1.00 mass%, and an _Al2O3 content of less than 0.50 mass% in the total iron ore. The method for producing sintered ore according to claim 3, wherein the composition of the sintering raw materials is adjusted so that the total iron ore contains 55.0 mass% or more of iron ore having an iron content of 60.0 mass% or more, a crystal water content of less than 4.00 mass%, an _Al2O3 content of less than 1.50 mass%, and _{a SiO2} content of 4.5 mass% or more and less than 5.0 mass%. The method for producing sintered ore according to claim 5, wherein the composition of the sintering raw material is adjusted so that a ratio of particles smaller than 0.5 mm in the total iron ore is 40.0 mass % or less.

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