Sintering method for optimizing distribution of magnesium oxide

Abstract

The invention relates to the technical field of ferrous metallurgy, and particularly discloses a magnesium oxide optimized distribution sintering method which comprises the following steps: step 1, preparing a high-alkalinity low-magnesium oxide sintering base material, taking return mine, iron ore concentrate, rich ore powder, dolomite powder and fuel as main raw materials, controlling the binary alkalinity to be 1.7-2.5 times, controlling the magnesium oxide content to be 1.5%, and preparing a high-alkalinity low-magnesium oxide sintering base material; after burdening and primary mixing, a high-alkalinity low-magnesium oxide sintered ore base material is formed; 2, flux type magnesium-based pellets are prepared, specifically, the concentrate powder and the fly ash serve as main materials, light calcined magnesia powder is added as a flux, the magnesium oxide content of the pellets is controlled to be 2%-3.5%, flux type magnesium-based green pellets with the particle size ranging from 5 mm to 8 mm are prepared through a pelletizing system, and the moisture content of the green pellets is controlled to be 8%-10% in the pelletizing process. According to the sintering method for optimized distribution of magnesium oxide, through a three-in-one process of raw material fine control, pelletizing structure optimization and embedded sintering cooperation, synchronous improvement of metallurgical performance, cost control and environmental protection indexes is achieved.

Description

Technical Field

[0001] The invention relates to the technical field of iron and steel metallurgy, and in particular to a sintering method for optimizing the distribution of magnesium oxide. Background Art

[0002] An appropriate amount of magnesium oxide (MgO) can optimize the binary and ternary basicity of slag, achieving ideal slag properties such as melting point, viscosity, and fluidity. This improves slag stability and fluidity, ensuring smooth slag discharge from the blast furnace. In traditional sintering processes, magnesium oxide (MgO) is often added directly to the sintering mix as a flux. Excessive MgO content can act as a refractory phase during sintering, increasing the liquidus temperature of the melt, requiring higher heat and reducing sintering speed. Furthermore, the addition of MgO inhibits the formation of calcium ferrite and increases the content of dicalcium silicate and transparent glass. These structures negatively impact the strength of the sintered ore, resulting in a significant decrease in the drum index. How to rationally transfer MgO from the incoming sintering feedstock—reducing the MgO content in the sintered ore to an appropriate level while also adding MgO through other methods to meet the requirements of blast furnace slag desulfurization—has been a challenge for the ironmaking industry. In addition, if vertical furnaces and rotary kilns are used to produce flux-type magnesium-based pellets to supplement the magnesium oxide content, there are technical bottlenecks such as production difficulties, high energy consumption, and insufficient pellet strength.

[0003] The present invention proposes an innovative process, which achieves optimized distribution of magnesium oxide and improves the comprehensive metallurgical properties of the sintered ore by embedding flux-type magnesium-based pellets into a sintering base material for sintering. Summary of the Invention

[0004] To achieve the above objectives, the present invention is implemented through the following technical solutions: A sintering method for optimizing the distribution of magnesium oxide, comprising the following steps: Step 1: prepare a high-basicity, low-magnesium oxide sinter base material, using return ore, iron ore concentrate, rich ore powder, and dolomite powder fuel as main raw materials, controlling the binary basicity within the range of 1.7-2.5 times, and the magnesium oxide content of 1.5%, and forming a high-basicity, low-magnesium oxide sinter base material after batching and one-time mixing; Step 2: Prepare flux-type magnesium-based pellets, mainly using concentrate powder and dust removal ash, adding light-burned magnesium oxide powder as flux, controlling the magnesium oxide content of the pellets to 2%-3.5%, and preparing 5mm-8mm flux-type magnesium-based green balls through a ball-making system. During the ball-making process, control the moisture content of the green balls to 8%-10%; Step 3: Embedded sintering process: 30%-60% of flux-type magnesium-based green balls are embedded in the sintering base material through a mixing outlet belt, and 50%-80% of sintering fuel is added simultaneously. After mixing through a secondary mixer, part of the fuel is added by rolling outwards, and then layered distribution is achieved through a multi-roller distributor to ensure that the pellets are evenly distributed in the sintering base material layer. During the sintering process, the sintering temperature is controlled at 1250℃-1350℃, the sintering time is 25-35 minutes, and a step-by-step heating method is adopted. The initial heating rate is 8-12℃ / minute. After the temperature reaches 1000℃, the heating rate is adjusted to 3-5℃ / minute.

[0005] Preferably, in the step 1, the particle size range of the return ore is controlled within 0.5-5 mm, and the residual carbon content in the return ore is not higher than 1.5%, the FeO content of the iron ore concentrate is ≤10%, the SiO2 content is ≤5%, the activity of the quicklime is ≥300 ml / 4N-HCl, the particle size ≤3 mm accounts for ≥90%, the MgO content of the dolomite powder is ≥19%, the particle size range is controlled to be ≤3 mm and accounts for ≥90%, (the fuel is coke powder, the particle size of which is controlled within 0.5-3 mm, the particle size of 0.5-3 mm accounts for more than 85%, the fixed carbon content is not less than 80%, and the volatile matter content is not higher than 1.5%.

[0006] Preferably, in the step 1, during the mixing, the speed of the mixer is controlled at 15-25 r / min, the mixing time is 3-5 minutes, a spiral guide plate is provided in the mixer, the pitch of the guide plate is 0.7 times the diameter of the mixer, and the filling rate of the material in the mixer is 40%-60%.

[0007] Preferably, in the step 2, the dust ash needs to be magnetically separated and impurities removed before use, and dried to reduce its moisture content to below 5%, the specific surface area of ​​the concentrate powder is controlled at 1800-2500 cm² / g, the Fe2O3 content is ≥65%, the particle size of the light-burned magnesium oxide powder is ≤0.074mm, accounting for ≥95%, and the ignition loss is ≤5%. The pelletizing system adopts a disc pelletizing machine with a pelletizing disc diameter of 5.5m-7.5m, an inclination angle of 45°-55°, and a rotation speed of 8-12r / min.

[0008] Preferably, in the step three, during the secondary mixing, the filling rate in the mixer is controlled at 30%-50%, the mixing time is 4-6 minutes, a lifting plate is provided in the mixer, the height of the lifting plate is 0.15 times the diameter of the mixer, and a staged water addition method is adopted, with the amount of water added in the first stage being 85%-90% of the total water volume, and the amount of water added in the second stage being 10%-15% of the total water volume.

[0009] Preferably, in the step three, when a multi-roller distributor is used to achieve layered distribution, the roller diameter of the distributor is 150-250 mm, the roller length is 1000-2000 mm, the spacing between adjacent rollers is 50-100 mm, the roller speed is 10-20 r / min, the cloth thickness is controlled at 600-800 mm, and the loose density of the material layer is 1.6-1.8 t / m³.

[0010] Preferably, in step three, during the sintering process, the sintering negative pressure is controlled at 10KPa-14KPa, the ignition temperature is 1100°C, the ignition time is 2 minutes, the sintering trolley speed is 2m / min, the sintering end point is controlled at the third-to-last bellows, and a segmented sintering cooling system is adopted, with a cooling rate of 12°C / min in the sintering section and a cooling rate of 25°C / min in the cooling section.

[0011] It has the following beneficial effects: This sintering method with optimized distribution of magnesium oxide achieves the simultaneous improvement of metallurgical performance, cost control and environmental protection indicators through the three-in-one process of refined raw material control, ball-forming structure optimization and embedded sintering coordination, significantly improves the strength and reducibility of sintered ore, reduces apparent porosity, optimizes mineral structure stability, greatly improves the utilization rate of low-grade raw materials, reduces flux and fuel consumption, and reduces comprehensive production costs; effectively reduces sulfur, nitrogen oxides and dust emissions in sintering flue gas, and improves the resource utilization rate of solid waste. In addition, the double-layer structure and MgO slow-release design realize the coordinated optimization of blast furnace slag desulfurization and sintered ore strength. The process is applicable to a variety of raw material systems and has a wide range of alkalinity adjustment. It breaks through the technical bottlenecks of strength degradation of traditional high-MgO sintered ore and difficulty in producing flux-type pellets, providing an innovative solution for low-carbon and high-efficiency sintering in the steel and metallurgical industry. DETAILED DESCRIPTION

[0012] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0013] In a first embodiment, the present invention provides a technical solution: a sintering method for optimizing the distribution of magnesium oxide, comprising the following steps: Step 1: Prepare high basicity low magnesium oxide sinter base material, using return ore, iron ore concentrate, rich ore powder, and dolomite powder fuel as the main raw materials, controlling the binary basicity to 2 times and the magnesium oxide content to 1.5%. After batching and mixing once, a high basicity low magnesium oxide sinter base material is formed. The specific process is as follows: According to the set formula, the automated batching system accurately weighs the raw materials from each raw material bin in the proportion of 15% sintering return material, 10% ironmaking return material, 54% rich ore powder, 10% concentrate powder, 6% quicklime, 1% coke powder, and 4% dolomite powder. The raw materials are sequentially conveyed to the feed port of the primary mixer via a belt conveyor, preliminarily mixed during the conveying process, and the mixer speed is adjusted to 20r / min; After the materials enter the mixer, the spiral guide plate installed in the mixer comes into play. The pitch of the guide plate is 0.7 times the diameter of the mixer. Under the guidance of the guide plate, the materials move along the spiral path in the mixer, which increases the contact and friction opportunities between the materials and promotes uniform mixing. The filling rate of the material in the mixer is controlled to 50%, and the mixing time is set to 4 minutes. During the mixing process, according to the characteristics and moisture content of the raw materials, water is added in an appropriate amount to make the moisture content of the mixture 7%. The uniform distribution of water helps to improve the air permeability and formability of the material; After the above ingredients are prepared and mixed once, a high basicity low magnesium oxide sintered ore base material with a binary basicity of 2 times and a magnesium oxide content of 1.5% is finally formed; Step 2: Prepare flux-type magnesium-based pellets, mainly using concentrate powder and dust removal ash, and adding light-burned magnesium oxide powder as flux. The magnesium oxide content of the pellets is controlled to 3%. The pelletizing system is used to prepare 7mm flux-type magnesium-based green pellets. During the pelletizing process, the moisture content of the green pellets is controlled at 9%. Step 3: Embedded sintering process: 45% of flux-type magnesium-based green balls are embedded at the place where the sintering base material passes through a mixing outlet belt, and 60% of sintering fuel is added simultaneously. The mixture is mixed in a secondary mixer. After part of the fuel is added by rolling, the multi-roller distributor is used to achieve layered distribution to ensure that the pellets are evenly distributed in the sintering base material layer. During the sintering process, the sintering temperature is controlled at 1300°C and the sintering time is 20 minutes. A step-by-step heating method is adopted with an initial heating rate of 10°C / minute. After the temperature reaches 1000°C, the heating rate is adjusted to 4°C / minute to promote full reaction and densification of the materials. During secondary mixing, the filling rate in the mixer is controlled at 40%, the mixing time is 5 minutes, a lifting plate is set in the mixer, the height of the lifting plate is 0.15 times the diameter of the mixer, and water is added in stages, with the water added in the first stage being 65% of the total water volume and the water added in the second stage being 35% of the total water volume; During the sintering process, the sintering negative pressure was controlled at 14 kPa, the ignition temperature was 1100 °C, the ignition time was 2 minutes, the sintering trolley speed was 2 m / min, the sintering end point was controlled at the third-to-last bellows, and a segmented sintering cooling system was adopted, with a cooling rate of 12 °C / min in the sintering section and a cooling rate of 25 °C / min in the cooling section.

[0014] In a second embodiment, the present invention provides a technical solution: a sintering method for optimizing the distribution of magnesium oxide, comprising the following steps: Step 1: Prepare high basicity low magnesium oxide sinter base material, using return ore, iron ore concentrate, rich ore powder, and dolomite powder fuel as the main raw materials, controlling the binary basicity to 1.7 times and the magnesium oxide content to 1.5%, and forming a high basicity low magnesium oxide sinter base material after batching and mixing. The specific process is as follows: According to the set formula, the automated batching system accurately weighs the raw materials from each raw material bin in the proportion of 15% sintering return material, 10% ironmaking return material, 54% rich ore powder, 10% concentrate powder, 6% quicklime, 1% coke powder, and 4% dolomite powder. The raw materials are sequentially conveyed to the feed port of the primary mixer via a belt conveyor, preliminarily mixed during the conveying process, and the mixer speed is adjusted to 15r / min; After the materials enter the mixer, the spiral guide plate installed in the mixer comes into play. The pitch of the guide plate is 0.7 times the diameter of the mixer. Under the guidance of the guide plate, the materials move along the spiral path in the mixer, which increases the contact and friction opportunities between the materials and promotes uniform mixing. The filling rate of the material in the mixer is controlled to 40%, and the mixing time is set to 3 minutes. During the mixing process, according to the characteristics and moisture content of the raw materials, water is added in an appropriate amount to make the moisture content of the mixture reach 7%. Even distribution of moisture helps to improve the air permeability and formability of the material; After the above ingredients are prepared and mixed once, a high basicity low magnesium oxide sintered ore base material with a binary basicity of 1.7 times and a magnesium oxide content of 1.5% is finally formed; Step 2: Prepare flux-type magnesium-based pellets, mainly using concentrate powder and dust removal ash, and adding light-burned magnesium oxide powder as flux. The magnesium oxide content of the pellets is controlled to 2%. 5mm flux-type magnesium-based green balls are prepared through a pelletizing system. During the pelletizing process, the moisture content of the green balls is controlled at 8%. The specific contents of the pelletizing process are as follows: Raw material pretreatment: The concentrate powder is finely ground by a ball mill, and the light-burned magnesium oxide powder is screened by an air classifier; Ingredient mixing: Use a powerful mixer to mix the dust ash 3%, light-burned dolomite powder 4%, binder 1.5%, and concentrate powder 91.5% at a ratio of 400r / min for 4 minutes. At the same time, introduce 0.4MPa atomized steam to adjust the material moisture to 7%. Ball forming: A disc ball forming machine with a diameter of 5m, an inclination of 50° and a rotation speed of 20r / min is used to form balls. Water is sprayed through an annular atomizing nozzle. The amount of water sprayed is proportionally distributed between the mother ball forming area and the growth area. The feeding rate is controlled so that the material stays in the disc for 18 minutes to form 7mm green balls. Quality inspection: Test the falling strength, compressive strength, moisture content and particle size of the green balls. Only those that meet the standards will enter the subsequent process. Step 3: Embedded sintering process: 60% of flux-type magnesium-based green balls are embedded at the place where the sintering base material passes through a mixing outlet belt, and 80% of the sintering fuel is added simultaneously. The mixture is mixed in a secondary mixer. After part of the fuel is added by rolling, the multi-roller distributor is used to achieve layered distribution to ensure that the pellets are evenly distributed in the sintering base material layer. During the sintering process, the sintering temperature is controlled at 1350℃, the sintering time is 35 minutes, and a step-by-step heating method is adopted. The initial heating rate is 12℃ / minute. After the temperature reaches 1000℃, the heating rate is adjusted to 5℃ / minute to promote full reaction and densification of the materials. During secondary mixing, the filling rate in the mixer is controlled at 50%, the mixing time is 6 minutes, a lifting plate is set in the mixer, the height of the lifting plate is 0.15 times the diameter of the mixer, and water is added in stages, with the water added in the first stage being 70% of the total water volume and the water added in the second stage being 40% of the total water volume; During the sintering process, the sintering negative pressure was controlled at 14 kPa, the ignition temperature was 1100 °C, the ignition time was 2 minutes, the sintering trolley speed was 2 m / min, the sintering end point was controlled at the third-to-last bellows, and a segmented sintering cooling system was adopted, with a cooling rate of 12 °C / min in the sintering section and a cooling rate of 25 °C / min in the cooling section.

[0015] In a third embodiment, the present invention provides a technical solution: a sintering method for optimizing the distribution of magnesium oxide, comprising the following steps: Step 1: Prepare high basicity low magnesium oxide sinter base material, using return ore, iron ore concentrate, rich ore powder, and dolomite powder fuel as the main raw materials, controlling the binary basicity to 2.5 times and the magnesium oxide content to 1.5%. After batching and mixing once, a high basicity low magnesium oxide sinter base material is formed. The specific process is as follows: According to the set formula, the automated batching system accurately weighs the raw materials from each raw material bin in the proportion of 15% sintering return material, 10% ironmaking return material, 54% rich ore powder, 10% concentrate powder, 6% quicklime, 1% coke powder, and 4% dolomite powder. The raw materials are sequentially conveyed to the feed port of the primary mixer via a belt conveyor, preliminarily mixed during the conveying process, and the mixer speed is adjusted to 25r / min; After the materials enter the mixer, the spiral guide plate installed in the mixer comes into play. The pitch of the guide plate is 0.7 times the diameter of the mixer. Under the guidance of the guide plate, the materials move along the spiral path in the mixer, which increases the contact and friction opportunities between the materials and promotes uniform mixing. Control the filling rate of materials in the mixer to 60%, which can ensure that the materials have enough space to tumble and mix, and ensure the working efficiency of the mixer; The mixing time is set to 5 minutes. During the mixing process, according to the characteristics and moisture content of the raw materials, water is added in appropriate amounts to make the moisture content of the mixture reach 7%. Evenly distributed moisture helps improve the air permeability and formability of the material. After the above ingredients are prepared and mixed once, a high basicity low magnesium oxide sintered ore base material with a binary basicity of 2.5 times and a magnesium oxide content of 1.5% is finally formed; Step 2: Prepare flux-type magnesium-based pellets, mainly using concentrate powder and dust removal ash, and adding light-burned magnesium oxide powder as a flux. The magnesium oxide content of the pellets is controlled at 3.5%. 8mm flux-type magnesium-based green balls are prepared through a pelletizing system. During the pelletizing process, the moisture content of the green balls is controlled at 10%. The specific contents of the pelletizing process are as follows: Raw material pretreatment: The concentrate powder is finely ground by a ball mill, and the light-burned magnesium oxide powder is screened by an air classifier, and its activity and loss on ignition are tested; Ingredient mixing: Use a powerful mixer to mix the dust ash 3%, light-burned dolomite powder 4%, binder 1.5%, and concentrate powder 91.5% at a ratio of 500r / min for 5 minutes, while introducing 0.5MPa atomized steam to adjust the material moisture to 8%; Ball forming: A disc ball forming machine with a diameter of 5m, an inclination of 55° and a rotation speed of 12r / min is used to form balls. Water is sprayed through an annular atomizing nozzle. The amount of water sprayed is proportionally distributed between the mother ball forming area and the growth area. The feed rate is controlled at 10t / h. The material stays in the disc for 18 minutes to form 8mm green balls. Quality inspection: Test the falling strength, compressive strength, moisture content and particle size of the green balls. Only those that meet the standards will enter the subsequent process. Step 3: Embedded sintering process: 60% of flux-type magnesium-based green balls are embedded at the place where the sintering base material passes through a mixing outlet belt, and 80% of the sintering fuel is added simultaneously. The mixture is mixed in a secondary mixer. After part of the fuel is added by rolling, the multi-roller distributor is used to achieve layered distribution to ensure that the pellets are evenly distributed in the sintering base material layer. During the sintering process, the sintering temperature is controlled at 1350℃, the sintering time is 35 minutes, and a step-by-step heating method is adopted. The initial heating rate is 12℃ / minute. After the temperature reaches 1000℃, the heating rate is adjusted to 5℃ / minute to promote full reaction and densification of the materials. During secondary mixing, the filling rate in the mixer is controlled at 50%, the mixing time is 6 minutes, a lifting plate is set in the mixer, the height of the lifting plate is 0.15 times the diameter of the mixer, and water is added in stages. The water addition amount in the first stage is 70% of the total water volume, and the water addition amount in the second stage is 40% of the total water volume; During the sintering process, the sintering negative pressure was controlled at 14 kPa, the ignition temperature was 1100 °C, the ignition time was 2 minutes, the sintering trolley speed was 2 m / min, the sintering end point was controlled at the third-to-last bellows, and a segmented sintering cooling system was adopted, with a cooling rate of 12 °C / min in the sintering section and a cooling rate of 25 °C / min in the cooling section.

[0016] Sintered material testing: Drum strength test: 15 kg of 10 mm sintered ore sample was placed in a 1000 mm diameter drum with 10 baffles. The drum was rotated at 25 rpm for 4 minutes. The material in the drum was then sieved through a 10 mm square hole sieve. The mass percentage of the +10 mm particle size was calculated as the drum index. 900°C Reducibility Index Test: 500g of 10mm sintered ore sample was placed in a 50mm inner diameter reduction tube. Under reducing gas conditions of 30% CO, 70% N2, and a flow rate of 15L / min, the sample was heated to 900°C at a heating rate of 10°C / min and held for 60min. The reducibility index was calculated based on the mass change of the sample before and after reduction. Low-temperature reduction pulverization rate test: Take 500g of 10mm sintered ore sample and heat it from room temperature to 500℃ at a heating rate of 10℃ / min in a reducing gas with a CO content of 15%, a CO2 content of 15%, and a N2 content of 70% at a flow rate of 15L / min. Hold the temperature for 60min. After cooling, place the sample in a rotating drum (130mm diameter, with 4 baffles, and a rotation speed of 30r / min) and rotate it for 10min. After screening, calculate the mass proportion of the +3.15mm and -0.5mm particle sizes respectively, which is used as the low-temperature reduction pulverization rate indicator. Apparent porosity and bulk density test: Select 4 regularly shaped sintered ore samples, first measure the external dimensions of the samples to calculate the volume V, then use the boiling method to boil the samples in water for more than 1 hour to saturate them with water. After taking them out, wipe the surface with a wet cloth and weigh the mass after saturation. Then dry the samples to constant weight and weigh the dry basis mass. According to the formula, where is the density of water, take 1g / cm³ to calculate the apparent porosity, and calculate the bulk density according to the formula; Mineral composition analysis: X-ray diffraction analysis method was used to grind the sintered ore sample to a particle size of less than 0.074 mm to prepare a powder sample. The sample was tested on an X-ray diffractometer. The content of minerals such as calcium ferrite, dicalcium silicate, and glass phase was calculated by analyzing the diffraction pattern using quantitative analysis software.

[0017] Obviously, the embodiments described are only some of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field and related fields without making creative efforts should fall within the scope of protection of the present invention. Structures, devices, and operating methods not specifically described and explained in the present invention shall be implemented in accordance with conventional means in the field unless otherwise specified or limited.

Claims

1. A sintering method for optimizing the distribution of magnesium oxide, characterized in that: The following steps are involved: Step 1: prepare a high-basicity, low-magnesium oxide sinter base material, using return ore, iron ore concentrate, rich ore powder, and dolomite powder fuel as main raw materials, controlling the binary basicity within the range of 1.7-2.5 times, and the magnesium oxide content of 1.5%, and forming a high-basicity, low-magnesium oxide sinter base material after batching and one-time mixing; Step 2: Prepare flux-type magnesium-based pellets, mainly using concentrate powder and dust removal ash, adding light-burned magnesium oxide powder as flux, controlling the magnesium oxide content of the pellets to 2%-3.5%, and preparing 5mm-8mm flux-type magnesium-based green balls through a ball-making system. During the ball-making process, control the moisture content of the green balls to 8%-10%; Step 3: Embedded sintering process: 30%-60% of flux-type magnesium-based green balls are embedded in the sintering base material through a mixing outlet belt, and 50%-80% of sintering fuel is added simultaneously. After mixing through a secondary mixer, part of the fuel is added by rolling outwards, and then layered distribution is achieved through a multi-roller distributor to ensure that the pellets are evenly distributed in the sintering base material layer. During the sintering process, the sintering temperature is controlled at 1250℃-1350℃, the sintering time is 25-35 minutes, and a step-by-step heating method is adopted. The initial heating rate is 8-12℃ / minute. After the temperature reaches 1000℃, the heating rate is adjusted to 3-5℃ / minute.

2. The sintering method for optimizing the distribution of magnesium oxide according to claim 1, characterized in that: In the step 1, the particle size range of the return ore is controlled within 0.5-5 mm, and the residual carbon content in the return ore is not higher than 1.5%, the FeO content of the iron ore concentrate is ≤10%, the SiO2 content is ≤5%, the activity of the quicklime is ≥300 ml / 4N-HCl, the particle size ≤3 mm accounts for ≥90%, the MgO content of the dolomite powder is ≥19%, the particle size range is controlled to be ≤3 mm, and the proportion is ≥90%. (The fuel is coke powder, the particle size of which is controlled within 0.5-3 mm, the proportion of 0.5-3 mm particle size is above 85%, the fixed carbon content is not less than 80%, and the volatile matter content is not higher than 1.5%.

3. The sintering method for optimizing the distribution of magnesium oxide according to claim 1, characterized in that: In the step 1, during the primary mixing, the mixer speed is controlled at 15-25 r / min, the mixing time is 3-5 minutes, a spiral guide plate is provided in the mixer, the guide plate pitch is 0.7 times the mixer diameter, and the material filling rate in the mixer is 40%-60%.

4. The sintering method for optimizing the distribution of magnesium oxide according to claim 1, characterized in that: In the step 2, the dust ash needs to be magnetically separated and impurities removed before use, and dried to reduce its moisture content to below 5%. The specific surface area of ​​the concentrate powder is controlled at 1800-2500 cm² / g, the Fe2O3 content is ≥65%, the particle size of the light-burned magnesium oxide powder is ≤0.074mm, accounting for ≥95%, and the ignition loss is ≤5%. The pelletizing system uses a disc pelletizing machine with a pelletizing disc diameter of 5.5m-7.5m, an inclination angle of 45°-55°, and a rotation speed of 8-12r / min.

5. The sintering method for optimizing the distribution of magnesium oxide according to claim 1, characterized in that: In the step three, during the secondary mixing, the filling rate in the mixer is controlled at 30%-50%, the mixing time is 4-6 minutes, a lifting plate is set in the mixer, the height of the lifting plate is 0.15 times the diameter of the mixer, and a staged water addition method is adopted. The amount of water added in the first stage is 85%-90% of the total water volume, and the amount of water added in the second stage is 10%-15% of the total water volume.

6. The sintering method for optimizing the distribution of magnesium oxide according to claim 1, characterized in that: In the step three, when a multi-roller distributor is used to achieve layered distribution, the roller diameter of the distributor is 150-250 mm, the roller length is 1000-2000 mm, the spacing between adjacent rollers is 50-100 mm, the roller speed is 10-20 r / min, the cloth thickness is controlled at 600-800 mm, and the loose density of the material layer is 1.6-1.8 t / m³.

7. The sintering method for optimizing the distribution of magnesium oxide according to claim 1, characterized in that: In the step three, during the sintering process, the sintering negative pressure is controlled at 10KPa-14KPa, the ignition temperature is 1100°C, the ignition time is 2 minutes, the sintering trolley speed is 2m / min, the sintering end point is controlled at the third-to-last bellows, and a segmented sintering cooling system is adopted, with a cooling rate of 12°C / min in the sintering section and a cooling rate of 25°C / min in the cooling section.