A flash treatment system and method for high phosphorus oolitic hematite ores

Abstract

The application belongs to the technical field of metallurgy, and particularly relates to a flash treatment system and method for high-phosphorus oolitic hematite ore; wherein the flash treatment system for high-phosphorus oolitic hematite ore comprises a feeding device, a reaction chamber, a collecting device and a magnetic separation device; the inner wall of the core reduction zone of the reaction chamber is provided with a composite ceramic working layer, which is prepared through a sectional hot-pressing sintering process and has high density, high hardness and excellent thermal shock resistance; in the treatment process, the high-phosphorus oolitic hematite ore and a dephosphorization aid are jointly ball milled and dried, then sprayed into a carrier gas, and flash reduction is carried out in the core reduction zone with hydrogen as a reducing agent; the reduced product is separated by magnetic separation to obtain metallic iron powder and tailings, realizing efficient dephosphorization and rapid reduction of the high-phosphorus oolitic hematite ore, and having the advantages of short process flow, short reduction time, high dephosphorization rate and clean environment.

Description

Technical Field

[0001] This invention belongs to the field of metallurgical technology, specifically relating to a flash processing system and method for high-phosphorus oolitic hematite ore. Background Technology

[0002] Iron ore powder is a mineral powder produced from iron ore through a series of processing steps including beneficiation, crushing, sorting, and grinding. It is a major raw material in ironmaking. Iron ore powder smelting involves mixing iron ore powder with a solid reducing agent and then smelting it in a blast furnace, where the iron oxides in the iron ore powder are reduced to metallic iron. my country has abundant reserves of high-phosphorus oolitic hematite, but due to its low grade and unique composition and chemical structure, it is considered one of the most difficult ores to smelt, leading to problems such as low beneficiation indicators and high costs in its production process.

[0003] Its oolitic structure is dense, and the phosphorus component is mostly embedded in the iron ore in the form of apatite, making it difficult to separate using conventional processes. Existing technologies struggle to balance reduction efficiency and dephosphorization effectiveness, resulting in resource waste and low production efficiency. Therefore, employing a novel reduction process to smelt high-phosphorus oolitic hematite ore and improve its metallization and dephosphorization rates is an urgent technical problem that needs to be solved in the metallurgical field. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention proposes a flash processing system and method for high-phosphorus oolitic hematite ore. The system includes a feeding device, a reaction chamber, a collection device, and a magnetic separation device. The inner wall of the core reduction zone in the reaction chamber is equipped with a composite ceramic working layer, and can be optionally equipped with a ball mill, a drying device, and a tail gas treatment device. The processing method, through steps such as crushing, drying, flash reduction, and magnetic separation, combined with a composite dephosphorization aid, achieves efficient processing of high-phosphorus oolitic hematite ore. This solves the problems of ineffective phosphorus analysis and high beneficiation costs in traditional high-phosphorus oolitic hematite ore smelting processes, improves iron reduction and dephosphorization effects, and achieves comprehensive resource utilization.

[0005] To address the shortcomings of existing technologies, the present invention adopts the following technical solution:

[0006] This invention provides a flash processing system for high-phosphorus oolitic hematite ore, comprising: a feeding device, a reaction chamber, a collecting device, and a magnetic separation device; wherein the feeding device, the reaction chamber, the collecting device, and the magnetic separation device are connected sequentially from top to bottom;

[0007] The feeding device includes an iron ore powder inlet, a granular carrier gas inlet, a concentrate nozzle, and a reducing gas inlet.

[0008] The reaction chamber is equipped with a reduction product outlet and is divided into an iron ore powder particle dispersion zone, a core reduction zone, and a cooling collection zone from top to bottom. The core reduction zone is heated by surrounding molybdenum disilicide rods, and the maximum temperature can reach 1600℃.

[0009] The iron ore powder inlet is connected to the top of the iron ore powder particle dispersion zone;

[0010] The collection device is equipped with a metal iron powder inlet, a tailings inlet, and a material collection tray. The material collected in the material collection tray is a reduction product of a mixture of metal iron powder and tailings.

[0011] The bottom of the cooling collection area of ​​the reaction chamber is connected to the inlet of metallic iron powder;

[0012] The magnetic separator is equipped with a reduction product inlet, a metallic iron powder outlet, and a tailings outlet;

[0013] The material collection tray is connected to the reduction product inlet;

[0014] In some embodiments of the present invention, the above-mentioned processing system further includes: a ball mill and a drying device, having an iron ore inlet and a wet iron ore powder particle outlet; the drying device having a wet iron ore powder particle inlet and a dry iron ore powder particle outlet, the wet iron ore powder particle outlet being connected to the wet iron ore powder particle inlet; the dry iron ore powder particle outlet being connected to the iron ore powder inlet.

[0015] In some embodiments of the present invention, the above-mentioned processing system further includes: an exhaust gas treatment device: having an exhaust gas inlet, an exhaust gas analysis system, a usable exhaust gas outlet, and a harmful exhaust gas collection device, wherein the exhaust gas inlet is connected to the top of the collection device, and the usable exhaust gas outlet is connected to a reducing gas inlet.

[0016] Furthermore, the inner wall surface of the core reduction zone of the reaction chamber is covered with a composite ceramic working layer;

[0017] The composite ceramic working layer comprises the following raw materials in parts by weight: 80-90 parts magnesium aluminum spinel, 8-15 parts MoSi2 and 2-5 parts Y2O3;

[0018] The method for preparing the composite ceramic working layer includes the following steps:

[0019] (1) Weigh magnesium aluminum spinel, MoSi2 and Y2O3 and add them to anhydrous ethanol. The ratio of the total mass of magnesium aluminum spinel, MoSi2 and Y2O3 to the volume of anhydrous ethanol is 1g:1.5mL. Add cemented carbide balls to the mixture. The ball-to-material mass ratio is 5:1. Mix the mixture using a planetary ball milling process. The milling time is 6-8 h and the milling speed is 300-350 r / min to obtain a uniform composite slurry.

[0020] (2) Place the composite slurry in a vacuum drying oven and dry it at 120°C for 10-12 h to fully remove the anhydrous ethanol solvent and water. After drying, pass the composite powder through a 100-mesh sieve to obtain a uniformly dispersed powder.

[0021] (3) The powder is loaded into a custom cylindrical mold that is perfectly matched with the working layer of the inner wall of the core reduction zone of the reaction chamber. 2-3% of anhydrous ethanol is added as a binder. After mixing evenly, the powder is compacted by cold isostatic pressing with a pressing pressure of 50-60 MPa and a holding time of 1-2 h. The green blank is then removed from the mold and left to stand at room temperature for 8-10 h to air dry naturally to remove residual moisture on the surface and prevent cracking of the green blank due to moisture evaporation during subsequent sintering. The dried blank is then obtained.

[0022] (4) Place the dry blank in a vacuum hot pressing sintering furnace, and introduce argon gas with a purity of ≥99.99% as a protective atmosphere to remove air and moisture from the furnace. Use a segmented heating sintering process. The specific steps are as follows:

[0023] The first stage (low-temperature degreasing): the temperature is increased from room temperature to 600℃ at a heating rate of 4℃ / min and held for 2 hours to completely remove residual moisture and a small amount of impurities from the green body and avoid porosity defects after sintering.

[0024] Second stage (medium-temperature pre-sintering): The temperature is increased from 600℃ to 1200℃ at a heating rate of 3℃ / min, and held for 3 hours;

[0025] The third stage (high-temperature densification sintering): The temperature is increased from 1200℃ to 1750-1800℃ at a heating rate of 2℃ / min, while an axial sintering pressure of 30-40 MPa is applied. The temperature and pressure are maintained for 2-3 hours to achieve complete densification of the composite powder. After sintering, the heating device is turned off, and an argon protective atmosphere is maintained. The furnace is allowed to cool naturally to room temperature to avoid cracking of the working layer due to thermal stress caused by rapid cooling, thus obtaining the composite ceramic working layer.

[0026] This invention also provides a flash processing method for high-phosphorus oolitic hematite ore, applied to the aforementioned system, specifically including the following steps:

[0027] S1, high-phosphorus oolitic hematite ore and dephosphorization aid are fed into a ball mill for grinding and crushing to obtain high-phosphorus oolitic hematite powder particles with a particle size of 50 μm;

[0028] S2, high-phosphorus oolitic hematite powder particles are fed into a drying device for baking and drying to obtain dried high-phosphorus oolitic hematite powder particles;

[0029] S3, dry high-phosphorus oolitic hematite powder particles are fed into the feeding device, and carrier gas is used to send them into the reaction chamber through the concentrate nozzle to obtain a high-phosphorus oolitic hematite powder particle flow with a larger dispersion ratio.

[0030] S4, reduce gas is introduced into the core reduction zone of the reaction chamber, and high phosphorus oolitic hematite powder particles are fed into the core reduction zone of the reaction chamber for reduction, to obtain a reduction product of mixed iron powder and tailings.

[0031] S5, the reduction product of the mixture of metallic iron powder and tailings is sent to a magnetic separator for separation to obtain metallic iron powder and tailings.

[0032] Furthermore, the carrier gas is one or both of H2 and Ar;

[0033] The carrier gas contains 30%-100% H2; its velocity is 0.05m / s-0.2m / s; and the mass flow rate of the concentrate nozzle is 0.5g / s-5g / s.

[0034] The reducing gas is H2, the temperature of the core reduction zone is 900℃-1400℃, and the reduction time is 3s-10s.

[0035] Furthermore, the dephosphorization aid comprises raw materials in the following mass ratio: calcium oxide:sodium carbonate = 75:25:

[0036] The preparation method of the dephosphorization aid includes the following steps:

[0037] (a) Weigh calcium oxide and sodium carbonate, place the two raw materials in an oven and dry them at 120℃ for 4 h to remove surface adsorbed moisture. Accurately weigh the dried raw materials and put them into the ball mill jar of a planetary ball mill. Add anhydrous ethanol as the ball milling medium. The mass ratio of the original total mass material to ethanol is 1:1.5. Then add cemented carbide grinding balls with a ball-to-material mass ratio of 3:1. Set the planetary ball mill speed to 250-300 r / min and the ball milling time to 2-4 h to ensure that calcium oxide and sodium carbonate are fully mixed and homogeneous to obtain a composite slurry.

[0038] (b) The composite slurry was transferred to a vacuum drying oven and dried at 80°C for 8-10 h to remove anhydrous ethanol. The dried powder was then passed through a 200-mesh sieve to obtain a dephosphorization aid with uniform particle size.

[0039] Compared with the prior art, the beneficial effects achieved by the present invention are as follows:

[0040] 1. The magnesium aluminum spinel-molybdenum disilicide composite ceramic working layer covering the inner wall of the core reduction zone of the reaction chamber adopts a structure with magnesium aluminum spinel as the continuous matrix phase and molybdenum disilicide as the dispersed reinforcing phase. The magnesium aluminum spinel matrix endows the working layer with high hardness and excellent wear resistance, which can resist the continuous scouring of high-speed iron ore powder particles. The uniformly distributed molybdenum disilicide particles effectively inhibit crack propagation through crack deflection and bridging mechanisms, so that the working layer maintains structural integrity when subjected to severe thermal cycling.

[0041] 2. The composite dephosphorization aid designed in this invention can fully contact and react with the phosphorus components in high-phosphorus oolitic hematite ore during flash reduction, effectively removing phosphorus from the ore, avoiding corrosion of equipment during the dephosphorization process, and balancing dephosphorization effect with equipment protection.

[0042] 3. The present invention utilizes hydrogen to treat high-phosphorus oolitic hematite ore, which greatly improves the dephosphorization rate and metallization rate of iron ore during the smelting process, and can comprehensively recover iron from high-phosphorus oolitic hematite ore, and the final product obtained is metallic iron powder.

[0043] 4. The process of this invention is short and low-cost, and the resulting iron powder has a high iron content, high iron recovery rate, low phosphorus content, and high dephosphorization rate. Attached Figure Description

[0044] The accompanying drawings provide a further understanding of the invention and form part of the specification. They are used together with the specific embodiments of the invention to explain the invention and do not constitute a limitation thereof.

[0045] Figure 1 This is a process flow diagram of a high-phosphorus oolitic hematite processing method according to Embodiment 2 of the present invention;

[0046] Figure 2 This is a schematic diagram of a high-phosphorus oolitic hematite processing system according to Embodiment 2 of the present invention.

[0047] The following are the labels in the attached diagram: 1. Furnace platform, 2. Bottom thermocouple of furnace body, 3. Corundum furnace tube, 4. High-temperature heating element molybdenum disilicide rod, 5. Middle thermocouple of furnace body, 6. Top thermocouple of furnace body, 7. Reducing gas inlet pipe, 8. Iron ore powder inlet, 9. Concentrate nozzle, 10. Top observation port of furnace body, 11. Insulated furnace lining, 12. Bottom observation port of furnace body, 13. Tail gas collection pipe, 14. Material tray, 15. Material tray observation and replacement port, 16. Tail gas treatment device. Detailed Implementation

[0048] To enable those skilled in the art to better understand the technical solutions of the present invention and to make the above-mentioned features, objectives, and advantages of the present invention clearer and easier to understand, the present invention will be further described below with reference to embodiments. These embodiments are for illustrative purposes only and are not intended to limit the scope of the present invention.

[0049] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those familiar to those skilled in the art. Furthermore, any methods and materials similar to or equivalent to those described herein may be applied to this invention. The preferred embodiments and materials described herein are for illustrative purposes only and do not limit the scope of this application.

[0050] Unless otherwise specified, all methods described in the following embodiments are conventional. Unless otherwise specified, all materials used in the following embodiments are new materials purchased from the market.

[0051] Reference Figure 2 The reducing gas inlet pipe 7, the iron ore powder inlet 8, and the concentrate nozzle 9 constitute the feeding device of the system. The carrier gas is used to make the iron ore powder particles achieve a greater dispersion effect in the reaction chamber through the concentrate nozzle.

[0052] The reaction chamber of this system consists of a corundum furnace tube 3, a high-temperature heating element molybdenum disilicide rod 4, and an insulating furnace lining 11. The reaction chamber is divided into three areas, from top to bottom: an iron ore powder particle dispersion area, a core reduction area, and a cooling and collection area. Since temperature affects the dispersion effect of iron ore powder particles and can cause some particles to react at the concentrate nozzle, affecting the service life of the concentrate nozzle, the high-temperature heating element molybdenum disilicide rod 4 is located in the middle of the reaction chamber as the core reduction area. The reduced iron ore powder particles are slowed down by the cooling and collection area at the bottom and then collected by the collection device at the bottom.

[0053] The reduction conditions of iron ore powder particles, the dispersion effect of iron ore powder particles inside the reaction chamber, and the collection of iron ore powder particles at the bottom of the furnace (2), the middle of the furnace (5), the top of the furnace (6), the observation port at the top of the furnace (10), and the bottom of the furnace (12) were respectively used to detect the reduction conditions of iron ore powder particles, the dispersion effect of iron ore powder particles inside the reaction chamber, and the collection of iron ore powder particles at the bottom.

[0054] The sloping furnace platform 1, material tray 14, and material tray observation and replacement port 15 form a collection device to collect the reduced iron ore powder particles. The material tray is taken out through the material tray observation and replacement port 15 when it is full.

[0055] The reduced iron ore powder particles in the material tray 14 are fed into the magnetic separator for magnetic separation to separate the metallic iron powder from the tailings.

[0056] The exhaust gas generated during reduction is introduced into the exhaust gas treatment device 16 through the exhaust gas collection pipe 13. In the exhaust gas treatment device 16, the gas is analyzed and processed. The hydrogen gas inside is purified and dried before being recycled as reducing gas. Other toxic gases are treated to render them harmless, thus eliminating the environmental damage caused by exhaust gas from traditional smelting equipment.

[0057] Reference Figure 1 The following examples were conducted:

[0058] Example 1: This example provides a flash processing system for high-phosphorus oolitic hematite ore, wherein the inner wall surface of the core reduction zone of the reaction chamber of the flash processing system for high-phosphorus oolitic hematite ore is covered with a composite ceramic working layer.

[0059] The composite ceramic working layer comprises the following raw materials in parts by weight: 80 parts magnesium aluminum spinel, 8 parts MoSi2 and 2 parts Y2O3;

[0060] The method for preparing the composite ceramic working layer includes the following steps:

[0061] (1) Weigh magnesium aluminum spinel, MoSi2 and Y2O3 and add them to anhydrous ethanol. The ratio of the total mass of magnesium aluminum spinel, MoSi2 and Y2O3 to the volume of anhydrous ethanol is 1g:1.5mL. Add cemented carbide balls to the mixture. The ball-to-material mass ratio is 5:1. Mix the mixture using a planetary ball milling process. The ball milling time is 6 h and the ball milling speed is 300 r / min to obtain a uniform composite slurry.

[0062] (2) Place the composite slurry in a vacuum drying oven and dry it at 120°C for 10 h to fully remove the anhydrous ethanol solvent and water. After drying, pass the composite powder through a 100-mesh sieve to obtain a uniformly dispersed powder.

[0063] (3) The powder is loaded into a custom cylindrical mold that is perfectly matched with the working layer of the inner wall of the core reduction zone of the reaction chamber. 2% anhydrous ethanol is added as a binder. After mixing evenly, the powder is compacted by cold isostatic pressing with a molding pressure of 50 MPa and a holding time of 1 h. The green blank is then removed from the mold and left to stand at room temperature for 8 h to air dry naturally to remove residual moisture on the surface and prevent cracking of the green blank due to moisture evaporation during subsequent sintering.

[0064] (4) Place the dry blank in a vacuum hot pressing sintering furnace, and introduce 99.99% pure argon gas as a protective atmosphere to remove air and moisture from the furnace. A segmented heating sintering process is adopted, and the specific steps are as follows:

[0065] The first stage: the temperature is increased from room temperature to 600℃ at a heating rate of 4℃ / min and held for 2 hours to completely remove residual moisture and a small amount of impurities from the green body and avoid porosity defects after sintering.

[0066] The second stage involves heating from 600℃ to 1200℃ at a rate of 3℃ / min and holding at that temperature for 3 hours to promote the initial bonding of magnesium aluminum spinel with MoSi2 particles and form a stable composite structure.

[0067] The third stage: the temperature is increased from 1200℃ to 1750℃ at a heating rate of 2℃ / min, while an axial sintering pressure of 30MPa is applied. The temperature and pressure are maintained for 2 hours to achieve complete densification of the composite powder. After sintering, the heating device is turned off, and an argon protective atmosphere is maintained. The furnace is allowed to cool naturally to room temperature to avoid cracking of the working layer due to thermal stress caused by rapid cooling. After cooling, the composite ceramic working layer is obtained.

[0068] This embodiment also provides a flash processing method for high-phosphorus oolitic hematite ore, applied to the aforementioned system, specifically including the following steps:

[0069] S1, the composition of high phosphorus oolitic hematite is Tfe 35.6%, P2O 51.9%, Fe2O 365.34%. The high phosphorus oolitic hematite and dephosphorization aid are fed into a ball mill for crushing to obtain high phosphorus oolitic hematite powder particles with a particle size of 50 μm.

[0070] S2, high-phosphorus oolitic hematite powder particles are fed into a drying device for baking and drying to obtain dried high-phosphorus oolitic hematite powder particles;

[0071] S3, dry high-phosphorus oolitic hematite powder particles are fed into the feeding device through the iron ore powder inlet of the feeding device. H2 is used as the carrier gas to provide the initial velocity, which is 0.05 m / s. After passing through the concentrate nozzle, it enters the reaction chamber in a dispersed state with a large specific surface area. The mass flow rate of the concentrate nozzle is 0.5 g / s.

[0072] S4, reducing gas is introduced into the reaction chamber. The reducing gas is 100% H2. The temperature of the reaction chamber is 900℃. Iron ore powder reacts with H2. The reaction time is 10s, and a reducing material containing metallic iron is generated.

[0073] S5, the reducing material is collected by the collection device and then passed into the magnetic separation device for magnetic separation to obtain high-quality metallic iron powder and tailings. The average mass fraction of iron in the iron powder is 94.6%. The tail gas after reduction is passed into the tail gas treatment device to purify, separate and dry the unreacted hydrogen gas, and then pass it into the reaction chamber for recycling.

[0074] The dephosphorization aid comprises raw materials in the following mass ratio: calcium oxide:sodium carbonate = 75:25:

[0075] The preparation method of the dephosphorization aid includes the following steps:

[0076] (a) Weigh calcium oxide and sodium carbonate, place the two raw materials in an oven and dry them at 120°C for 4 h to remove surface adsorbed moisture. Accurately weigh the dried raw materials and put them into the ball mill jar of a planetary ball mill. Add anhydrous ethanol as the ball milling medium. The mass ratio of the original total mass material to ethanol is 1:1.5. Then add cemented carbide grinding balls. The mass ratio of the balls to the material is 3:1. Set the speed of the planetary ball mill to 250 r / min and the ball milling time to 2 h to make the calcium oxide and sodium carbonate fully mixed and uniform to obtain a composite slurry.

[0077] (b) The composite slurry was transferred to a vacuum drying oven and dried at 80°C for 8 h to completely remove anhydrous ethanol. The dried powder was then passed through a 200-mesh sieve to obtain a dephosphorization aid with uniform particle size.

[0078] Example 2: This example provides a flash processing system for high-phosphorus oolitic hematite ore, wherein the inner wall surface of the core reduction zone of the reaction chamber of the flash processing system for high-phosphorus oolitic hematite ore is covered with a composite ceramic working layer.

[0079] The composite ceramic working layer comprises the following raw materials in parts by weight: 85 parts magnesium aluminum spinel, 10 parts MoSi2 and 3 parts Y2O3;

[0080] The method for preparing the composite ceramic working layer includes the following steps:

[0081] (1) Weigh magnesium aluminum spinel, MoSi2 and Y2O3 and add them to anhydrous ethanol. The ratio of the total mass of magnesium aluminum spinel, MoSi2 and Y2O3 to the volume of anhydrous ethanol is 1g:1.5mL. Add cemented carbide balls to the mixture. The ball-to-material mass ratio is 5:1. Mix the mixture using a planetary ball milling process. The milling time is 7 h and the milling speed is 350 r / min to obtain a uniform composite slurry.

[0082] (2) The composite slurry was placed in a vacuum drying oven and dried at 120°C for 11 h to fully remove the anhydrous ethanol solvent and water. The dried composite powder was passed through a 100-mesh sieve to obtain a uniformly dispersed powder.

[0083] (3) The powder is loaded into a custom cylindrical mold that is perfectly matched with the working layer of the inner wall of the core reduction zone of the reaction chamber. 2.5% anhydrous ethanol is added as a binder. After mixing evenly, the powder is compacted by cold isostatic pressing with a molding pressure of 55 MPa and a holding time of 1.5 h. The green blank is then removed from the mold and left to stand at room temperature for 9 h to air dry naturally to remove residual moisture on the surface and prevent cracking of the green blank due to moisture evaporation during subsequent sintering. The dried blank is then obtained.

[0084] (4) Place the dry blank in a vacuum hot pressing sintering furnace, and introduce 99.99% pure argon gas as a protective atmosphere to remove air and moisture from the furnace. A segmented heating sintering process is adopted, and the specific steps are as follows:

[0085] The first stage: the temperature is increased from room temperature to 600℃ at a heating rate of 4℃ / min and held for 2 hours to completely remove residual moisture and a small amount of impurities from the green body and avoid porosity defects after sintering.

[0086] The second stage involves heating from 600℃ to 1200℃ at a rate of 3℃ / min and holding at that temperature for 3 hours to promote the initial bonding of magnesium aluminum spinel with MoSi2 particles and form a stable composite structure.

[0087] The third stage: the temperature is increased from 1200℃ to 1800℃ at a heating rate of 2℃ / min, while an axial sintering pressure of 35MPa is applied. The temperature and pressure are maintained for 2.5 h to achieve complete densification of the composite powder. After sintering, the heating device is turned off, and an argon protective atmosphere is maintained. The furnace is allowed to cool naturally to room temperature to avoid cracking of the working layer due to thermal stress caused by rapid cooling. After cooling, the composite ceramic working layer is obtained.

[0088] This embodiment also provides a flash processing method for high-phosphorus oolitic hematite ore, applied to the aforementioned system, specifically including the following steps:

[0089] S1, the composition of high phosphorus oolitic hematite is Tfe 35.6%, P2O 51.9%, Fe2O 365.34%. The high phosphorus oolitic hematite and dephosphorization aid are fed into a ball mill for crushing to obtain high phosphorus oolitic hematite powder particles with a particle size of 50 μm.

[0090] S2, high-phosphorus oolitic hematite powder particles are fed into a drying device for baking and drying to obtain dried high-phosphorus oolitic hematite powder particles;

[0091] S3, dry high-phosphorus oolitic hematite powder particles are fed into the feeding device through the iron ore powder inlet of the feeding device. A mixture of H2 and Ar is used as the carrier gas to provide the initial velocity. The proportion of H2 in the carrier gas is 60%, and the velocity is 0.1 m / s. After passing through the concentrate nozzle, it enters the reaction chamber in a dispersed state with a large specific surface area. The mass flow rate of the concentrate nozzle is 2.5 g / s.

[0092] S4, reducing gas is introduced into the reaction chamber. The reducing gas is 100% H2. The temperature of the reaction chamber is 950℃. The iron ore powder reacts with H2 for 3 seconds to produce a reduced material containing metallic iron.

[0093] S5, the reducing material is collected by the collection device and then passed into the magnetic separation device for magnetic separation to obtain high-quality metallic iron powder and tailings. The reduced tail gas is passed into the tail gas treatment device to purify, separate and dry the unreacted hydrogen gas, and then pass it into the reaction chamber for recycling.

[0094] The dephosphorization aid comprises raw materials in the following mass ratio: calcium oxide:sodium carbonate = 75:25:

[0095] The preparation method of the dephosphorization aid includes the following steps:

[0096] (a) Weigh calcium oxide and sodium carbonate, place the two raw materials in an oven and dry them at 120°C for 4 h to remove surface adsorbed moisture. Accurately weigh the dried raw materials and put them into the ball mill jar of a planetary ball mill. Add anhydrous ethanol as the ball milling medium. The mass ratio of the original total mass material to ethanol is 1:1.5. Then add cemented carbide grinding balls with a ball-to-material mass ratio of 3:1. Set the planetary ball mill speed to 300 r / min and the ball milling time to 3 h to ensure that calcium oxide and sodium carbonate are fully mixed and homogeneous to obtain a composite slurry.

[0097] (b) The composite slurry was transferred to a vacuum drying oven and dried at 80°C for 9 h to completely remove anhydrous ethanol. The dried powder was then passed through a 200-mesh sieve to obtain a dephosphorization aid with uniform particle size.

[0098] Example 3: This example provides a flash processing system for high-phosphorus oolitic hematite ore, wherein the inner wall surface of the core reduction zone of the reaction chamber of the flash processing system for high-phosphorus oolitic hematite ore is covered with a composite ceramic working layer.

[0099] The composite ceramic working layer comprises the following raw materials in parts by weight: 90 parts magnesium aluminum spinel, 15 parts MoSi2 and 5 parts Y2O3;

[0100] The method for preparing the composite ceramic working layer includes the following steps:

[0101] (1) Weigh magnesium aluminum spinel, MoSi2 and Y2O3 and add them to anhydrous ethanol. The ratio of the total mass of magnesium aluminum spinel, MoSi2 and Y2O3 to the volume of anhydrous ethanol is 1g:1.5mL. Add cemented carbide balls to the mixture. The ball-to-material mass ratio is 5:1. Mix the mixture using a planetary ball milling process. The ball milling time is 8 h and the ball milling speed is 350 r / min to obtain a uniform composite slurry.

[0102] (2) Place the composite slurry in a vacuum drying oven and dry it at 120°C for 12 h to fully remove the anhydrous ethanol solvent and water. After drying, pass the composite powder through a 100-mesh sieve to obtain a uniformly dispersed powder.

[0103] (3) The powder is loaded into a custom cylindrical mold that is perfectly matched with the working layer of the inner wall of the core reduction zone of the reaction chamber. Anhydrous ethanol of 3% of the powder mass is added as a binder. After mixing evenly, the powder is compacted by cold isostatic pressing with a molding pressure of 60 MPa and a holding time of 2 h. The green blank is then removed from the mold and left to stand at room temperature for 10 h to air dry naturally to remove residual moisture on the surface and prevent cracking of the green blank due to moisture evaporation during subsequent sintering.

[0104] (4) Place the dry blank in a vacuum hot pressing sintering furnace, and introduce 99.99% pure argon gas as a protective atmosphere to remove air and moisture from the furnace. A segmented heating sintering process is adopted, and the specific steps are as follows:

[0105] The first stage: the temperature is increased from room temperature to 600℃ at a heating rate of 4℃ / min and held for 2 hours to completely remove residual moisture and a small amount of impurities from the green body and avoid porosity defects after sintering.

[0106] The second stage involves heating from 600℃ to 1200℃ at a rate of 3℃ / min and holding at that temperature for 3 hours to promote the initial bonding of magnesium aluminum spinel with MoSi2 particles and form a stable composite structure.

[0107] The third stage: the temperature is increased from 1200℃ to 1800℃ at a heating rate of 2℃ / min, while an axial sintering pressure of 40 MPa is applied. The temperature and pressure are maintained for 3 hours to achieve complete densification of the composite powder. After sintering, the heating device is turned off, and an argon protective atmosphere is maintained. The furnace is allowed to cool naturally to room temperature to avoid cracking of the working layer due to thermal stress caused by rapid cooling. After cooling, the composite ceramic working layer is obtained.

[0108] This embodiment also provides a flash processing method for high-phosphorus oolitic hematite ore, applied to the aforementioned system, specifically including the following steps:

[0109] S1, the composition of high phosphorus oolitic hematite is Tfe 35.6%, P2O 51.9%, Fe2O 365.34%. The high phosphorus oolitic hematite and dephosphorization aid are fed into a ball mill for crushing to obtain high phosphorus oolitic hematite powder particles with a particle size of 50 μm.

[0110] S2, high-phosphorus oolitic hematite powder particles are fed into a drying device for baking and drying to obtain dried high-phosphorus oolitic hematite powder particles;

[0111] S3, dry high-phosphorus oolitic hematite powder particles are fed into the feeding device through the iron ore powder inlet of the feeding device. Ar is used as the carrier gas to provide the initial velocity, which is 0.2 m / s. After passing through the concentrate nozzle, it enters the reaction chamber in a dispersed state with a large specific surface area. The mass flow rate of the concentrate nozzle is 5 g / s.

[0112] S4, reducing gas is introduced into the reaction chamber. The reducing gas is 100% H2. The temperature of the reaction chamber is 1400℃. Iron ore powder reacts with H2. The reaction time is 4s, and a reducing material containing metallic iron is generated.

[0113] S5, the reducing material is collected by the collection device and then passed into the magnetic separation device for magnetic separation to obtain high-quality metallic iron powder and tailings. The reduced tail gas is passed into the tail gas treatment device to purify, separate and dry the unreacted hydrogen gas, and then pass it into the reaction chamber for recycling.

[0114] The dephosphorization aid comprises raw materials in the following mass ratio: calcium oxide:sodium carbonate = 75:25:

[0115] The preparation method of the dephosphorization aid includes the following steps:

[0116] (a) Weigh calcium oxide and sodium carbonate, place the two raw materials in an oven and dry them at 120°C for 4 h to remove surface adsorbed moisture. Accurately weigh the dried raw materials and put them into the ball mill jar of a planetary ball mill. Add anhydrous ethanol as the ball milling medium. The mass ratio of the original total mass material to ethanol is 1:1.5. Then add cemented carbide grinding balls. The mass ratio of the balls to the material is 3:1. Set the speed of the planetary ball mill to 300 r / min and the ball milling time to 4 h to make the calcium oxide and sodium carbonate fully mixed and uniform to obtain a composite slurry.

[0117] (b) The composite slurry was transferred to a vacuum drying oven and dried at 80°C for 10 h to remove anhydrous ethanol. The dried powder was then passed through a 200-mesh sieve to obtain a dephosphorization aid with uniform particle size.

[0118] The difference between Comparative Example 1 and Example 2 is that the inner wall of the core reduction zone of the reaction chamber is made of ordinary refractory material, while the rest is exactly the same as Example 2.

[0119] The difference between Comparative Example 2 and Example 2 is that no dephosphorization aid is added; the rest is exactly the same as Example 2.

[0120] Comparative Example 3 uses a conventional processing method for high-phosphorus oolitic hematite, namely reduction roasting-magnetic separation.

[0121] Experimental example:

[0122] 1. Dephosphorization rate: Weigh the mixture of reduced metallic iron powder and tailings, mix thoroughly, and take a sample. Determine the mass fraction of phosphorus in the sample using inductively coupled plasma optical emission spectrometry (ICP-OES), denoted as P. Simultaneously, determine the phosphorus content of the untreated high-phosphorus oolitic hematite raw material using the same method. The dephosphorization rate is calculated using the following formula: The calculation results are recorded in Table 1.

[0123] 2. Iron Recovery Rate: Weigh the total mass of the mixture of reduced metallic iron powder and tailings, denoted as M0. After magnetic separation, collect the metallic iron powder product and weigh its mass, denoted as M1. Determine the mass fraction of iron in the mixture (Fe0) and the mass fraction of iron in the metallic iron powder (Fe1), respectively. The iron recovery rate is calculated using the following formula: The results are recorded in Table 1.

[0124] Table 1: Dephosphorization rate and iron recovery rate of the flash processing system for high-phosphorus oolitic hematite ore according to the present invention

[0125]

[0126] In Table 1, the reaction chamber wall of Comparative Example 1 was made of ordinary refractory material. During the flash reduction process, after multiple thermal cycles, microcracks appeared on the inner wall. Some iron ore powder particles were retained at the cracks and underwent over-reduction, resulting in a small amount of phosphorus entering the metallic iron phase. At the same time, the inner wall surface wore down quickly, affecting the powder dispersion effect. Comparative Example 2 did not add any composite dephosphorization aid and relied solely on the kinetic selectivity of the flash reduction process to achieve iron-phosphorus separation.

[0127] Comparative Example 3 employs a common reduction roasting-magnetic separation process in existing technologies: iron ore and coal powder are mixed and pelletized, reduced roasted for 2-2.5 hours, cooled, crushed, ball-milled, and magnetically separated. While this process achieves higher dephosphorization and iron recovery rates, the reduction roasting time is as long as 2-2.5 hours, whereas this invention only requires 3-10 seconds, significantly improving production efficiency.

[0128] In summary, this invention provides a flash processing system for high-phosphorus oolitic hematite ore. This system integrates a feeding device, a reaction chamber, a collection device, and a magnetic separation device, and is also equipped with a ball milling device, a drying device, and a tail gas treatment device. The inner wall of the core reduction zone in the reaction chamber is lined with a composite ceramic working layer, prepared through specific ball milling, molding, and sintering processes to ensure structural stability and suitability for the reduction reaction. The processing method, through steps such as ball milling, drying, feeding and dispersion, high-temperature reduction, and magnetic separation, combined with reasonable control of carrier gas and reducing gas, achieves flash processing of high-phosphorus oolitic hematite ore, enabling rational resource utilization and environmentally friendly treatment. This system can meet the needs for large-scale, high-efficiency processing of high-phosphorus oolitic hematite ore.

[0129] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A flash processing system for high-phosphorus oolitic hematite ore, characterized in that, The flash processing system for the high-phosphorus oolitic hematite ore includes: a feeding device, a reaction chamber, a collecting device, and a magnetic separation device; the feeding device, the reaction chamber, the collecting device, and the magnetic separation device are connected sequentially from top to bottom; The reaction chamber is divided into an iron ore powder particle dispersion zone, a core reduction zone, and a cooling and collection zone from top to bottom. The inner wall surface of the core reduction zone is covered with a composite ceramic working layer. The composite ceramic working layer comprises the following raw materials in parts by weight: 80-90 parts magnesium aluminum spinel, 8-15 parts MoSi2 and 2-5 parts Y2O3; The method for preparing the composite ceramic working layer includes the following steps: (1) Weigh magnesium aluminum spinel, MoSi2 and Y2O3, add them to anhydrous ethanol, add cemented carbide balls to it, and use planetary ball milling process to mix and mill to obtain composite slurry; (2) The composite slurry is vacuum dried and sieved to obtain powder; (3) The powder is compacted by cold isostatic pressing to obtain a green blank, which is then dried at room temperature to obtain a dry blank. (4) The dry blank is subjected to vacuum hot pressing sintering, a protective atmosphere is introduced, and it is cooled to obtain a composite ceramic working layer.

2. The flash processing system for high-phosphorus oolitic hematite ore according to claim 1, characterized in that, The flash processing system for high-phosphorus oolitic hematite ore also includes: a ball mill, a drying unit, and a tail gas treatment unit, wherein the outlet of the ball mill is connected to the inlet of the drying unit; the outlet of the drying unit is connected to the inlet of the feeding unit; and the inlet of the tail gas treatment unit is connected to the top of the collection unit.

3. The flash processing system for high-phosphorus oolitic hematite ore according to claim 1, characterized in that, In step (4), the vacuum hot pressing sintering adopts a segmented heating sintering process, and the specific steps are as follows: First stage: Increase the temperature from room temperature to 600℃ at a heating rate of 4℃ / min and hold for 2 hours; Second stage: Increase the temperature from 600℃ to 1200℃ at a heating rate of 3℃ / min and hold for 3 hours; The third stage: the temperature is increased from 1200℃ to 1750-1800℃ at a heating rate of 2℃ / min, while an axial sintering pressure of 30-40 MPa is applied, and the temperature and pressure are maintained for 2-3 hours.

4. A flash processing method for high-phosphorus oolitic hematite ore applied to the system described in claim 2, characterized in that, Specifically, the following steps are included: S1, high-phosphorus oolitic hematite ore and dephosphorization aid are fed into a ball mill for crushing to obtain high-phosphorus oolitic hematite powder particles; S2, high-phosphorus oolitic hematite powder particles are fed into a drying device for baking and drying to obtain dried high-phosphorus oolitic hematite powder particles; S3, dry high-phosphorus oolitic hematite powder particles are fed into the feeding device, and carrier gas is used to send them into the reaction chamber through the concentrate nozzle to obtain a high-phosphorus oolitic hematite powder particle stream; S4, reduce gas is introduced into the core reduction zone of the reaction chamber, and high phosphorus oolitic hematite powder particles are fed into the core reduction zone of the reaction chamber for reduction, to obtain a reduction product of mixed iron powder and tailings. S5, the reduction product of the mixture of metallic iron powder and tailings is sent to a magnetic separator for separation to obtain metallic iron powder and tailings.

5. The flash processing method for high-phosphorus oolitic hematite ore according to claim 4, characterized in that, The dephosphorization aid comprises raw materials in the following mass ratio: calcium oxide: sodium carbonate = 75:25; The preparation method of the dephosphorization aid includes the following steps: (a) Weigh calcium oxide and sodium carbonate, dry them, and ball mill them to obtain a composite slurry; (b) The composite slurry is vacuum dried and sieved to obtain a dephosphorization aid.

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