A production method of ultra-low FeO sintered ore

Abstract

The invention discloses a method for producing ultra-low FeO sintered ore, belonging to the technical field of iron and steel metallurgy. The method is to divide the fuel into two parts, fuel I and fuel II, and mix and granulate fuel I with sintering raw materials to obtain sintered material; distribute the sintered material to the sintering machine, and then distribute fuel II on the surface of the sintered material; ignite, keep warm, sinter and cool; during the sintering process, spray oxygen-rich gas medium to the surface of the sintered material; during the cooling process, first exhaust air cooling on the sintering machine, and then unload to the ring cooler for cooling. The method reduces the sintering fuel ratio to increase the oxygen potential of the sintering material layer, thereby improving the FeO oxidation efficiency of the sintered ore, and can produce sintered ore with ultra-low FeO (<6.5%) content. The method can not only greatly reduce the solid fuel consumption of sintering and the FeO content of the sintered ore, but also improve the reducibility of the sintered ore, reduce the blast furnace coke ratio, and thus reduce the overall fuel consumption level of the ironmaking process.

Description

Technical Field

[0001] The invention relates to a method for producing sintered ore, in particular to a method for producing ultra-low FeO sintered ore, and belongs to the technical field of iron and steel metallurgy. Background Art

[0002] Sintered ore, as the product of iron ore sintering, is a high-quality ironmaking raw material for blast furnaces. The quality of its quality indicators plays a key role in whether the blast furnace can operate stably. FeO content is one of the important indicators for evaluating the quality of sintered ore. In order to ensure the low-temperature reduction and pulverization performance of sintered ore, the current blast furnace operation usually controls the FeO content of sintered ore at a high level (8%~10%). High FeO content means that the solid fuel consumption of sintering is maintained at a high level, which makes it impossible to effectively apply some low-carbon sintering technologies, restricting the implementation of low-carbon sintering. At the same time, high FeO content is not conducive to the reducibility of sintered ore, reduces the reduction efficiency of blast furnaces, and is not conducive to the reduction of blast furnace coke ratio. In the late 1970s and early 1980s, Europe and Japan controlled the FeO of sintered ore within 6%. According to existing research, for every 1% reduction in FeO in sintered ore, the coke ratio of the blast furnace can be reduced by about 2%, and the output can be increased by about 2%. In summary, low-FeO sintered ore has good smelting advantages and the potential to reduce fuel consumption.

[0003] With the advancement of blast furnace ironmaking technology, the blast furnace utilization factor has been greatly improved compared with 30 years ago. The determination of the low-temperature reduction pulverization index of sintered ore requires the use of reducing gas at 500℃ for 60 minutes, while the actual residence time of sintered ore in the low-temperature zone of the blast furnace has been greatly shortened. The pulverization phenomenon in the blast furnace block belt is relatively mild, and the permeability of the block belt has little effect. Therefore, modern blast furnaces can appropriately reduce the requirements for the reduction pulverization index of sintered ore. After the 1980s, Europe and Japan have not used the reduction pulverization rate (RDI-0.5) as the main control indicator. In actual production, Japan controls the RDI (-0.5) value to no more than 42%. Although the production of low-FeO sintered ore will reduce the low-temperature reduction pulverization index of sintered ore to a certain extent, its pulverization degree is still acceptable to the blast furnace and will not have a significant impact on the smooth operation of the blast furnace. Therefore, without affecting the smooth operation of the blast furnace, the production of ultra-low FeO sintered ore is beneficial to the reduction of sintering solid fuel consumption and the reduction of blast furnace coke ratio, thereby reducing the fuel consumption of the ironmaking process as a whole.

[0004] The Chinese patent (publication number CN101338363A) discloses a method for preparing high-titanium type low-FeO content sintered ore using Panzhihua's unique vanadium-titanium magnetite concentrate as raw material. The sintering raw material is high-titanium type vanadium-titanium magnetite concentrate, the carbon content is 2.6-3.2% during batching, the FeO content of the sintered ore is 6.5-9.5%, and the FeO content is preferably 7.0-8.5% as the best. The FeO content of the sintered ore is controlled to 6.5-9.5% by controlling the high-precision fuel ratio, ensuring the strength of the sintered ore and improving the metallurgical properties. However, the proportion of concentrate in the mixture of this method is too high, which is not conducive to the production of low-FeO sintered ore; the thickness of the sintering material layer is 500~680mm, which is a certain distance from the ultra-high material layer, and the sintering heat storage effect cannot be better utilized. When the FeO content in the sintered ore is controlled below 6%, the drum strength and yield of the sintered ore are relatively low, and the low-temperature reduction pulverization rate is high. For example, by adjusting the carbon content to 2.4%, the drum strength of the sintered ore is 68.67%, the yield is 60.80%, and the low-temperature reduction pulverization rate is 74.84%. Summary of the invention

[0005] In view of the technical problems existing in the prior art, the purpose of the present invention is to provide a method for producing ultra-low FeO sintered ore. The method reduces the maximum temperature of the sintering combustion zone, optimizes the oxygen content of the sintering material layer, enhances the oxidation rate of FeO in the sintered ore, and implements partial on-machine cooling to further promote the oxidation of FeO, so as to achieve the production of ultra-low FeO sintered ore. It not only reduces the sintering solid fuel consumption, but also improves the reducibility of the sintered ore, maintains high drum strength and yield, and further reduces the coke ratio of the blast furnace, providing a new method for carbon reduction and emission reduction in the ironmaking and sintering processes of the steel industry, which can produce huge economic and environmental benefits.

[0006] The ultra-low FeO sintered ore involved in the present invention, wherein ultra-low means that the FeO mass content is lower than 6.5%, more preferably lower than 5.8%.

[0007] In order to achieve the above technical objectives, the present invention provides a method for producing ultra-low FeO sintered ore, which comprises the following steps:

[0008] 1) The fuel is divided into two parts, fuel I and fuel II. Fuel I is mixed and pelletized with sintering raw materials to obtain sintering materials. The mass proportion of fuel I in the fuel is 90% to 95%, and the mass proportion of fuel II is 5% to 10%;

[0009] 2) Place the sintering material on the sintering machine, and then place fuel II on the surface of the sintering material;

[0010] 3) Ignition, insulation, sintering and cooling;

[0011] During the sintering process, an oxygen-rich gas medium is sprayed toward the surface of the sintering material; the oxygen volume proportion of the oxygen-rich gas medium is 21% to 23%, and the spraying time is 10 to 16 minutes;

[0012] During the cooling process, the sintering machine is first cooled by exhaust air, and then the material is unloaded into a ring cooler for cooling; during the cooling process, the time for exhaust air cooling on the sintering machine is 6 to 15 minutes.

[0013] The production method of ultra-low FeO sintered ore provided by the present invention is to improve the following aspects: on the one hand, the distribution of fuel is changed, and part of the fuel is distributed in the thick material layer and part of the fuel is distributed on the sintering material surface. The purpose is to reduce the fuel ratio of sintering as much as possible, so that the maximum sintering temperature is not higher than 1300°C, and low-temperature sintering is achieved. The mineral composition and structure of the ideal sintered ore should have a part of unreacted residual hematite (about 40%) and a heterogeneous structure with needle-shaped crystals of calcium silicoaluminoferrite (SFCA) as the main bonding phase (about 40%). This sintered ore has high reducibility, good low-temperature reduction pulverization performance and high cold strength. This needle-shaped calcium ferrite is formed at a relatively low temperature. When the temperature rises, it will melt and decompose into other forms. When the temperature is higher than 1350°C, the hematite will also decompose into magnetite, which promotes the production of magnetite. Therefore, the sintering should be strictly controlled to be carried out at a relatively low temperature. Secondly, during the sintering process, spraying oxygen-rich gas medium onto the sintering material surface can not only weaken the local reducing atmosphere in the sintering combustion zone and reduce the reduction rate of Fe2O3 under high temperature, but also increase the oxidation rate of the upper sintered ore that has been sintered, and reduce the FeO content of the upper sintered ore. Thirdly, the sintered ore is cooled by cooling on the sintering machine after sintering because the cooling of the sintered ore on the machine is more conducive to the oxidation of FeO in the sintered ore than the cooling of the ring cooler. Although the FeO content of the lower sintered ore is relatively high, during the exhaust cooling, the cooling air is heated during the cooling of the upper material layer, making the cooling temperature of the lower material layer high and the oxidation reaction easier to proceed. Therefore, increasing the cooling time on the machine as much as possible can greatly reduce the FeO content level of the lower material layer of the sintered ore, thereby reducing the FeO content of the overall sintered ore. At the same time, the high-temperature hot exhaust gas formed by the cooling on the machine can be used for heat preservation after sintering ignition, thereby enhancing the sintering quality. In summary, the present invention can obtain ultra-low FeO sintered ore through the above improvements, and the sintered ore has high drum strength and high yield, and reduces solid fuel consumption.

[0014] As a preferred solution, the particle size distribution of the fuel is as follows: the mass proportion of particles <3 mm is greater than 85%, and the mass proportion of particles <0.5 mm is less than 20%. Coarse particle size of the fuel will cause serious segregation during the distribution process, and large particles in the fuel will easily go to the lower layer, which will cause insufficient fuel in the upper and middle parts of the sintering material layer, and it will be impossible to form a sufficient liquid phase, resulting in a decrease in the drum strength of the sintered ore, a deterioration in the particle size composition, an excess of fuel in the lower material layer, and an excessively high temperature in the sintering material layer, which is not conducive to the formation of composite calcium ferrite. At a higher temperature, calcium ferrite will decompose into hematite or magnetite, and hematite will decompose into magnetite at a higher temperature, thereby increasing the FeO content; if the fuel particle size is too fine, the combustion speed will increase, the high temperature residence time of the material layer during the sintering process will be shortened, the sintering liquid phase will not develop sufficiently, the quality of the sintered ore will deteriorate, and the drum strength and yield rate will decrease; at the same time, the fuel particle size is small and it is easy to be carried away by the airflow, which deteriorates the air permeability of the sintering material layer.

[0015] As a preferred solution, the fuel accounts for less than 3.5% of the mass of the sintering material, and more preferably, the fuel accounts for 2.8-3.4% of the mass of the sintering material.

[0016] The technical solution of the present invention, in order to reduce the FeO content of sintered ore, firstly needs to reduce the overall ratio of sintering fuel. The present invention utilizes the heat storage effect of sintering and distributes part of the fuel to the sintering material surface to make the heat distribution of the overall sintering material layer more uniform. This method can further reduce the overall fuel ratio of sintering, thereby reducing the FeO content of sintered ore.

[0017] As a preferred solution, the iron grade in the sintering material is not less than 57%, the mass content of MgO is 1.6% to 1.8%, the mass content of SiO2 is 4.5% to 5.5%, the mass content of Al2O3 is 1.5% to 2.0%, and the binary basicity is 1.8 to 2.2. The optimization basis of the chemical composition of the sintering material of the present invention is that too low MgO content will increase the low-temperature reduction pulverization rate of the sintered ore, so the MgO content should not be too low. On the other hand, the Mg in MgO 2+ Will enter the magnetite lattice to replace Fe 2+, and fills in the vacancies of the magnetite octahedron, thereby reducing the degree of defects in the magnetite lattice, stabilizing the magnetite and increasing the FeO content, so the MgO content should not be too high; SiO2 will form a fayalite liquid phase with Fe3O4 at a lower temperature, so too high SiO2 will increase the FeO content, and too low SiO2 will affect the formation of composite calcium ferrite; suitable Al2O3 in the sintered ore can promote the formation of calcium ferrite and form composite calcium ferrite, and at the same time it is beneficial to reduce the viscosity of the sintering liquid phase, promote the diffusion of oxygen ions, and is beneficial to the oxidation of the sintered ore. Too high Al2O3 will increase the low-temperature reduction pulverization rate of the sintered ore; keep the basicity of the sintered ore not less than 1.8, so that the calcium ferrite content in the sintered ore reaches more than 30~40%, ensuring the quality of the sintered ore. Too high basicity of the sintered ore will reduce the iron grade of the sintered ore and increase the amount of blast furnace slag, which is not good for the blast furnace.

[0018] As a preferred solution, the mixing adopts a strong mixing method, the strong mixing speed is 300-800 rpm, and the time is 1-3 minutes. The present invention can obtain a better mixing effect through strong mixing, the sintering fuel and the flux can be evenly distributed, and the fuel segregation is avoided during the sintering process, so as to achieve the effect of homogeneous sintering.

[0019] As a preferred solution, the thickness of the sintering material on the sintering machine is 900-1000 mm. There is an obvious positive correlation between the FeO content of the sintered ore and the sintering fuel ratio, and the present invention preferably adopts thick material layer sintering technology and utilizes the sintering heat storage effect to further reduce the sintering fuel ratio.

[0020] As a preferred solution, the ignition temperature is 900±50°C and the ignition time is 60~90s.

[0021] The technical solution of the present invention increases the oxygen potential in the material layer by introducing an oxygen-rich gas medium into the material layer, promotes rapid combustion of the fuel, and weakens the reducing atmosphere at the same time.

[0022] According to the technical solution of the present invention, the on-machine cooling of sintered ore can obtain sintered ore with lower FeO content compared with the cooling in the ring cooler. On the one hand, this is because the exhaust cooling has a larger cooling air volume and higher oxidation efficiency than the blast cooling. On the other hand, although the FeO content of the lower layer of sintered ore is relatively higher than that of the upper layer after sintering, during the exhaust cooling, the cooling air is heated in the process of cooling the upper material layer, so that the cooling temperature of the lower material layer is high, and the FeO oxidation rate of the lower layer of sintered ore is very fast. Therefore, after on-machine cooling, the lower layer of sintered ore will be reduced to a lower level, thereby reducing the FeO content of the overall sintered ore.

[0023] As a preferred solution, the insulation time is 1 to 5 minutes. In order to make the heat distribution in the height direction of the sintering material layer more uniform and make up for the lack of heat in the upper material layer, the hot exhaust gas from the cooling section of the sintering machine can be directly used for sintering insulation.

[0024] Compared with the prior art, the technical solution of the present invention has the following beneficial technical effects:

[0025] (1) The present invention adopts thick-bed sintering technology based on the heat storage effect of sintering and the phenomenon of uneven heat distribution in the longitudinal direction of the material layer, and distributes part of the fuel on the sintering material surface, so that the heat distribution of the sintering material layer is more uniform, which can significantly reduce the sintering fuel ratio and achieve the effect of carbon reduction and emission reduction.

[0026] (2) The present invention introduces oxygen-rich medium gas during sintering, which is very beneficial for improving the oxygen potential of the material layer, promoting fuel combustion and the formation of calcium ferrite binding phase. At the same time, it can weaken the sintering reducing atmosphere, reduce the reduction of hematite, and reduce the FeO content of the sintered ore.

[0027] (3) The on-machine cooling of sintered ore adopted in the present invention can obtain sintered ore with lower FeO content compared with the cooling of ring cooler. At the same time, the hot exhaust gas obtained by on-machine cooling can be circulated for sintering heat preservation to make up for the insufficient heat of the upper material layer of sintering, thereby improving the sintering quality.

[0028] (4) The ultra-low FeO sintered ore produced by the present invention has a FeO content of no more than 6.5%, has good reducibility, can reduce the blast furnace coke ratio to a certain extent, and has significant economic benefits. At the same time, the sintered ore maintains good drum strength and yield rate. DETAILED DESCRIPTION

[0029] In order to facilitate understanding of the content of the present invention, the present invention will be described more comprehensively and carefully in combination with preferred embodiments below, but the protection scope of the claims of the present invention is not limited to the following specific embodiments.

[0030] Unless otherwise defined, all professional terms used below have the same meanings as those generally understood by those skilled in the art. The professional terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the scope of protection of the claims of the present invention.

[0031] Example 1

[0032] According to the sintering mixture composition TFe=57.6%, MgO=1.74%, SiO2=5.35%, Al2O3=1.96%, binary basicity CaO / SiO2=2.16, the coke powder ratio is 3.4%, of which the particle size <3mm accounts for 87%, <1mm accounts for 15%, 92% of the total coke powder is taken and mixed with the sintering mixture vigorously for 1min at a speed of 500rpm, and then granulated, the mixture is spread on the sintering machine at a height of 950mm, and then the remaining (total 8%) coke powder is spread on the surface of the sintering mixture. Ignition is carried out at 900±50℃ for 1min, the heat preservation time is 3min, and then sintering is carried out under negative pressure of 15kPa. After the sintering ignition is completed, oxygen-rich medium gas is sprayed onto the material surface for 10 minutes, wherein the oxygen volume concentration is 21.6%. When the sintering flue gas temperature reaches the highest point, the sintering is completed. The sintered ore is continued to be cooled by exhaust air on the sintering machine for 15 minutes, and then unloaded to the ring cooler for cooling. After adopting the method described in this embodiment, the effects on the sintering index, FeO content, and metallurgical properties are shown in Tables 1 and 2.

[0033] Example 2

[0034] According to the sintering mixture composition TFe=57.6%, MgO=1.74%, SiO2=5.35%, Al2O3=1.96%, binary basicity CaO / SiO2=2.16, the coke powder ratio is 3.3%, of which the particle size <3mm accounts for 87%, <1mm accounts for 15%, 90% of the total coke powder is taken and mixed with the sintering mixture vigorously for 1min at a speed of 500rpm, and then granulated, the mixture is spread on the sintering machine at a height of 950mm, and then the remaining (total 10%) coke powder is spread on the surface of the sintering mixture. Ignition is carried out at 900±50℃ for 1min, the heat preservation time is 3min, and then sintering is carried out under negative pressure of 15kPa. After the sintering ignition is completed, oxygen-rich medium gas is sprayed onto the material surface, the spraying time is 13 minutes, the oxygen volume concentration is 22.1%, and the sintering is completed when the sintering flue gas temperature reaches the highest point. The sintered ore is continued to be cooled by exhaust air on the sintering machine, the cooling time is 15 minutes, and then unloaded to the ring cooler for cooling. After adopting the method described in this embodiment, the effects on the sintering index, FeO content, and metallurgical properties are shown in Tables 1 and 2.

[0035] Example 3

[0036] According to the sintering mixture composition TFe=57.6%, MgO=1.74%, SiO2=5.35%, Al2O3=1.96%, binary basicity CaO / SiO2=2.16, the coke powder ratio is 3.1%, of which the particle size <3mm accounts for 87%, <1mm accounts for 15%, 95% of the total coke powder is taken and mixed with the sintering mixture vigorously for 1min at a speed of 500rpm, and then granulated, the mixture is spread on the sintering machine at a height of 950mm, and then the remaining (total 5%) coke powder is spread on the surface of the sintering mixture. Ignition is carried out at 900±50℃ for 1min, the heat preservation time is 3min, and then sintering is carried out under negative pressure of 15kPa. After the sintering ignition is completed, oxygen-rich medium gas is sprayed onto the material surface for 15 minutes, and the oxygen volume concentration is 22.6%. When the sintering flue gas temperature reaches the highest point, the sintering is completed. The sintered ore is continued to be cooled by exhaust air on the sintering machine for 10 minutes, and then unloaded to the ring cooler for cooling. After adopting the method described in this embodiment, the effects on the sintering index, FeO content, and metallurgical properties are shown in Tables 1 and 2.

[0037] Comparative Example 1

[0038] According to the sintering mixture composition TFe = 57.6%, MgO = 1.74%, SiO2 = 5.35%, Al2O3 = 1.96%, binary basicity CaO / SiO2 = 2.26, the coke powder ratio is 3.4%, of which the particle size <3mm accounts for 87%, <1mm accounts for 15%. The sintering mixture is vigorously mixed for 1min at a speed of 500rpm, and then granulated. The mixture is distributed to the sintering machine with a distribution height of 950mm. Ignition is carried out at 1000±50℃ for 1min, the insulation time is 3min, and then sintering is carried out under negative pressure of 15kPa. The sintering index, FeO content, and the influence of metallurgical properties are shown in Tables 1 and 2.

[0039] Comparative Example 2

[0040] According to the sintering mixture composition TFe=57.6%, MgO=1.74%, SiO2=5.35%, Al2O3=1.96%, binary basicity CaO / SiO2=2.16, the coke powder ratio is 3.4%, of which the particle size <3mm accounts for 87%, <1mm accounts for 15%, the sintering mixture is vigorously mixed for 1min, the speed is 500rpm, and then granulated, the mixture is distributed to the sintering machine, the distribution height is 950mm. Ignition is carried out at 1000±50℃ for 1min, the insulation time is 3min, and then sintering is carried out under negative pressure of 15kPa. After the sintering ignition is completed, oxygen-rich medium gas is sprayed onto the material surface, the spraying time is 10min, the oxygen volume concentration is 21.6%, and the sintering is completed when the sintering flue gas temperature reaches the highest point. The sintered ore is continued to be cooled by exhaust on the sintering machine for 15min, and then discharged to the ring cooler for cooling. After adopting the method described in this embodiment, the influence on sintering index, FeO content and metallurgical properties is shown in Table 1 and Table 2.

[0041] Comparative Example 3

[0042] According to the sintering mixture composition TFe=57.6%, MgO=1.74%, SiO2=5.35%, Al2O3=1.96%, binary basicity CaO / SiO2=2.16, the coke powder ratio is 3.3%, of which the particle size <3mm accounts for 87%, <1mm accounts for 15%, 90% of the total coke powder is taken and mixed with the sintering mixture vigorously for 1min, the speed is 500rpm, and then granulation is carried out. The mixture is spread on the sintering machine with a spreading height of 950mm, and then the remaining (total 10%) coke powder is spread on the surface of the sintering mixture. Ignition is carried out at 900±50℃ for 1min, the insulation time is 3min, and then sintering is carried out under negative pressure of 15kPa. When the sintering flue gas temperature reaches the highest point, the sintering is completed, and the sintered ore is continued to be cooled by exhaust on the sintering machine for 15min, and then discharged to the ring cooler for cooling. After adopting the method described in this embodiment, the influence on sintering index, FeO content and metallurgical properties is shown in Table 1 and Table 2.

[0043] Comparative Example 4

[0044] According to the sintering mixture composition TFe=57.6%, MgO=1.74%, SiO2=5.35%, Al2O3=1.96%, binary basicity CaO / SiO2=2.16, the coke powder ratio is 3.1%, of which the particle size <3mm accounts for 87%, <1mm accounts for 15%, 95% of the total coke powder is taken and mixed with the sintering mixture for 1min, the speed is 500rpm, and then granulation is carried out. The mixture is spread on the sintering machine with a spreading height of 950mm, and then the remaining (total 5%) coke powder is spread on the surface of the sintering mixture. Ignition is carried out at 900±50℃ for 1min, the insulation time is 3min, and then sintering is carried out under negative pressure of 15kPa. After the sintering ignition is completed, oxygen-rich medium gas is sprayed onto the material surface. The spraying time is 15min, and the oxygen volume concentration is 22.6%. When the sintering flue gas temperature reaches the highest point, the sintering is completed and the material is unloaded to the ring cooler for cooling. After adopting the method described in this embodiment, the influence on sintering index, FeO content and metallurgical properties is shown in Table 1 and Table 2.

[0045]

[0046]

Claims

1. A method for producing ultra-low FeO sintered ore, characterized in that: The following steps are involved: 1) The fuel is divided into two parts, fuel I and fuel II. Fuel I is mixed and granulated with sintering raw materials to obtain sintering material. The mass proportion of fuel I in the fuel is 90% to 95%, and the mass proportion of fuel II is 5% to 10%. The particle size distribution of the fuel is as follows: the mass proportion of particle size <3 mm is greater than 85%, and the mass proportion of particle size <0.5 mm is less than 20%. The iron grade in the sintering material is not less than 57%, the mass content of MgO is 1.6% to 1.8%, the mass content of SiO2 is 4.5% to 5.5%, the mass content of Al2O3 is 1.5% to 2.0%, and the binary basicity is 1.8 to 2.

2. 2) Spread the sintering material on the sintering machine, and then spread the fuel II on the surface of the sintering material; the thickness of the sintering material on the sintering machine is 900~1000mm; 3) Ignition, insulation, sintering and cooling; During the sintering process, an oxygen-rich gas medium is sprayed toward the surface of the sintering material; the volume proportion of oxygen in the oxygen-rich gas medium is 21% to 23%, and the spraying time is 10 to 16 minutes; During the cooling process, the sintering machine is first cooled by exhaust air, and then the material is discharged to a ring cooler for cooling; during the cooling process, the time for exhaust air cooling on the sintering machine is 6 to 15 minutes; The ultra-low FeO sintered ore refers to an FeO mass content of less than 5.8%.

2. The method for producing ultra-low FeO sintered ore according to claim 1, characterized in that: The fuel accounts for less than 3.5% of the mass of the sintering material.

3. The method for producing ultra-low FeO sintered ore according to claim 1, characterized in that: The mixing is carried out in a strong mixing manner, the strong mixing speed is 300-800 rpm, and the time is 1-3 minutes.

4. The method for producing ultra-low FeO sintered ore according to claim 1, characterized in that: The ignition temperature is 900±50°C and the ignition time is 60~90s.

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