High-speed iron red mud reactive distillation dealkalization carbon fixation and reduction ironmaking process

Abstract

This invention provides a process for reactive distillation of red mud for dealkalization, carbon fixation, and reduction in ironmaking for high-speed ferrosilicon production. The red mud slurry is pumped to the top of a reactive distillation tower, where it comes into countercurrent contact with flue gas through multi-stage through-flow trays and packing. The acidic gases in the flue gas react with the alkali in the slurry in a highly efficient reactive distillation process. The flue gas, after dust removal, decarbonization, and desulfurization, flows out from the top of the reactive distillation tower, while the dealkalized and carbon-fixed red mud slurry flows out from the bottom of the tower, having been dehydrated and removed from concentrated brine. The dehydrated red mud slurry is then diluted again with a portion of the washing brine before being pumped... At the top of the water washing desalination tower, countercurrent water washing desalination is carried out. The brine flowing out from the top of the water washing desalination tower is partially used to dilute the dehydrated red mud slurry, and the remainder is mixed with concentrated brine and sent back to the alumina extraction section. The dehydrated red mud slurry flowing out from the bottom of the water washing desalination tower is dehydrated and then heated and fluidized by the reduced tail gas from the supplementary combustion. It is then subjected to gasification reduction magnetization reaction and magnetic separation using ironmaking tail gas. The refined iron ore powder and coal powder are mixed in the Y-type gasification reduction ironmaking furnace for in-situ gasification reduction ironmaking.

Description

Technical Field

[0001] This invention provides a process for reactive distillation, dealkali removal, carbon fixation, and reduction ironmaking of high-speed iron red mud, which belongs to the field of environmental protection. Background Technology

[0002] Red mud is a highly alkaline pollutant waste residue discharged during the extraction of alumina in the electrolytic aluminum industry. On average, 1.0 to 2.0 tons of red mud are generated for every ton of alumina produced. Resource utilization is an internationally recognized effective means of utilizing red mud. Although five major utilization technologies have been developed domestically and internationally, namely powder materials, element extraction, cementing materials, road materials, and building ceramics materials, they are all currently in the technological development stage and have not yet been commercialized.

[0003] The high-value utilization of ferrous red mud containing over 30% iron oxide produced in the Bayer process has been a persistent challenge. The fundamental reason is the excessive sodium oxide content and high non-magnetic iron oxide content in the red mud. Red mud is a highly alkaline solid waste with a pH as high as 11-13. The alkaline substances in red mud are mainly of two types: soluble alkali (free alkali) and insoluble alkali (bound alkali). Free alkali mainly includes NaOH, Na₂CO₃, and NaHCO₃. 3、 Insoluble alkalis include NaAl(OH)4, Na2SiO3, etc., and include calcite, nepheline, hydrated garnet, sodalite, and tricalcium aluminate. Nepheline is the main alkali-containing substance, with sodium oxide (Na2O) being the main alkaline oxide in its chemical composition, accounting for up to 12.91%, mainly in the form of caustic soda, sodium aluminate, and sodium aluminosilicate. Soluble alkalis can be removed by CO2 or water washing at normal temperature and pressure, but this part accounts for a small proportion. Most of the alkalis are insoluble, especially in Bayer process red mud, where sodium silicate slag accounts for a large proportion, about 35-45%. The removal of this part of the alkali is one of the most difficult problems to solve globally and a key issue affecting the further large-scale utilization of red mud. In addition, the iron oxides contained in high-iron red mud include not only strongly magnetic magnetite (Fe3O4), but also non-magnetic or weakly magnetic needle-like iron oxide, sodium ferrite, and ferric hydroxide, which directly affect the magnetic separation effect and recovery rate. There is an urgent need for efficient, rapid, and low-cost reduction magnetization technology and equipment.

[0004] Electrolytic aluminum production is a high-energy-consuming and high-polluting industry, and is typically supported by large-scale thermal power plants. These plants process CO2 and SO2 from the flue gas. x and NO xUsing acidic gases for red mud dealkali removal can achieve acid-base neutralization and waste-to-waste treatment, while efficiently and cost-effectively solving the two major challenges of red mud dealkali removal and flue gas decarbonization and ultra-low emissions. Alcoa in Western Australia has already extensively applied the CO2 method for dealkali removal, adding gaseous and liquid CO2 to thickened red mud slurry. The CO2 reacts with the alkaline components in the slurry to achieve dealkali removal. However, current methods using gas dispersion by introducing flue gas into the red mud slurry or red mud slurry spraying achieve dealkali removal rates of less than 50%. Furthermore, due to SO2... x Stronger acidity than CO2, it readily reacts with insoluble alkaline substances, significantly improving the dealkali removal rate. However, existing flue gas dealkali removal processes have not yet achieved staged utilization of flue gas, making insoluble alkaline substances a persistent problem in red mud dealkali removal. Therefore, there is an urgent need to develop multiphase flow reactive distillation dealkali removal and carbon fixation technology and equipment for high-speed iron red mud flue gas, as well as its reduction ironmaking process, to overcome the challenges posed by SO2. x This technology addresses industrial bottlenecks such as efficient CO2 utilization based on reactivity, slurry blockage, and efficient dispersion, mass transfer, and reaction, and constructs a high-value utilization industrial chain for high-iron red mud resources, providing a guarantee for the sustainable and high-quality development of the electrolytic aluminum industry. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of existing technologies for the resource utilization of high-speed iron red mud by proposing a reactive distillation process for dealkalization, carbon fixation, and reduction ironmaking of high-speed iron red mud. This process not only solves the problem of removing insoluble alkaline substances from red mud in a low-cost and efficient manner, but also addresses the challenge of high-value utilization of high-speed iron red mud resources through fluidized bed drying, reduction magnetization, magnetic separation, and in-situ reduction ironmaking in a gas flow bed. Furthermore, it enables the efficient utilization of acidic gases in flue gas according to their reactivity, thus solving the problems of decarbonization and ultra-low emissions of combustion flue gas at a high efficiency and low cost.

[0006] The technical solution of the present invention:

[0007] This invention provides a reactive distillation process for dealkalization, carbon fixation, and reduction ironmaking using high-iron red mud. High-iron red mud slurry at 10-100℃ is pumped to the top of a reactive distillation column, where it comes into counter-current contact with mixed flue gas at 30-180℃ introduced from the bottom of the column via a cross-flow tray or packing with 1-30 theoretical plates. The feed ratio of mixed flue gas to red mud slurry is 500-3000:1 (volume ratio). The process reduces the concentration of CO2 and SO2 in the flue gas within the reactive distillation column. x and NO x Acidic gases undergo efficient reactive distillation with Na₂O, K₂O, and their basic salts in the slurry, producing SO₂. x and NO xThe reaction mainly occurs in the lower part of the column with insoluble alkaline substances, while CO2 mainly reacts with soluble alkaline substances in the upper part of the column, reducing the pH value of the red mud slurry from 11-14 to no more than 8. The purified flue gas is discharged from the top of the reactive distillation column, while the de-alkali-fixed and carbon-fixed ferrous red mud slurry flows out from the bottom of the reactive distillation column and is dehydrated of concentrated brine. The dehydrated ferrous red mud slurry is diluted again with some wash brine and then pumped to the top of the water washing desalting column for countercurrent water washing desalting. Part of the wash brine flowing out from the top of the water washing desalting column is used to dilute the dehydrated red mud slurry, and part is mixed with concentrated brine and sent back to the alumina extraction section. The dehydrated red mud slurry flowing out from the bottom of the water washing desalting column is dehydrated and sent to a fluidized bed dryer. It is heated by the reduction tail gas after supplemental combustion and then fluidized. The dried tail gas obtained from gas-solid separation at the top of the fluidized bed dryer is mixed with the flue gas and sent to the bottom of the reactive distillation column. The gas-solid separation at the top of the fluidized bed dryer... The separated, dried, desalinated high-iron red mud is fed into a fluidized bed reduction reactor, where it undergoes a reduction and magnetization reaction with ironmaking tail gas at 1300-1700℃. The reduction tail gas obtained from the gas-solid separation at the top of the fluidized bed reduction reactor is used as the fluidized drying gas for the fluidized bed drying tower after heat recovery by combustion. The reduced red mud obtained from the gas-solid separation at the top of the reduction fluidized bed reduction reactor is cooled and then magnetically separated to recover refined iron ore powder. The refined iron ore powder and coal powder are mixed and fed into a Y-type fluidized bed gasification reduction ironmaking furnace using an oxidant. In-situ gasification reduction ironmaking is carried out at 1300-1700℃. The high-temperature molten iron, slag, and ironmaking tail gas flow downward into the settling separator at the bottom of the Y-type fluidized bed gasification reduction ironmaking furnace. After settling and stratification, molten iron, slag, and ironmaking tail gas are obtained from different outlets. The ironmaking tail gas is sent back to the fluidized bed reduction reactor, while the molten iron and slag are discharged as products.

[0008] The reactive distillation column is a cross-flow structure without downcomers. A high-iron red mud slurry distributor is installed at the top of the column. The tray spacing of the cross-flow column is 250-900 mm. A mixed flue gas distributor is installed at the bottom of the column. The top of the column is the purified flue gas outlet, and the bottom of the column is the dealkalized and carbonized red mud slurry outlet.

[0009] The CO2 content in the combustion flue gas is 12%-25%, SO2 content is 25%. x Content ranges from 0-50000 ppm, NO x The content is 0-3000 ppm, and the flue gas velocity in the reactive distillation column is 0.5-3.0 m / s.

[0010] The concentration of red mud slurry for high-speed railways is 5%-60% by mass, and the spraying density inside the tower is 5-120 m³ / h. 3 / (m 2 •h).

[0011] Water washing desalination towers can be cross-flow plate towers, packed towers, or empty towers.

[0012] The fluidized bed drying tower is a bubbling fluidized bed, a turbulent fluidized bed, or a riser conveying bed, and the fluidized drying temperature is 100~180℃.

[0013] The fluidized reduction reactor is a pulse riser reactor, riser conveying bed, bubbling fluidized bed or turbulent fluidized bed. The reduction magnetization reaction temperature is 700-1300℃. The purity of the refined iron ore powder from magnetic separation is 40%-95%. The magnetic separation residue is used as a raw material for soil remediation agents, road materials or building ceramic materials.

[0014] The upper part of the Y-type fluidized bed gasification reduction blast furnace is a cylindrical gasification section, and the lower part is a cylindrical settling separator. The gasification section and settling separator have an inverted T-shaped structure. The gasification section adopts a water-cooled refractory lining layer, and the top is equipped with a downward spray nozzle. There are more than three side nozzles along the circumference in the upper middle part, and the nozzles are distributed in an inverted Y-shaped structure. The side nozzles have an angle of -15° to 15° with the horizontal direction and an angle of -5° to 75° with the radial direction. The settling separator adopts a heat-insulating lining and has a slag outlet, a siphon-type molten iron outlet, and an emergency treatment port at the bottom. The emergency treatment port at the bottom of the settling separator ensures venting in case of shutdown or emergency.

[0015] The operation of the Y-type fluidized bed gasification reduction blast furnace involves uniformly mixing fine iron ore powder and pulverized coal at a C:Fe2O3 ratio of 1:1.1-4.0 and feeding the mixture into a mixing bin. The iron-coal mixture from the mixing bin, along with the gasifying agent, is injected into the gasification section through the top nozzle and radially inclined side nozzles of the Y-type fluidized bed gasification reduction blast furnace, where gasification and reduction occur at a temperature of 1300-1700℃. Multiple jets generated by the top and side nozzles collide with each other at the center of the furnace, forming a Y-shaped rotating impact high-temperature reaction zone, mutually igniting and enhancing the gasification and reduction reaction. Iron coke residue is thrown against the furnace wall of the gasification section, swirling downwards. The iron coke residue remains in the gasification section during the reaction... The time interval is extended by more than 10 times, and a solidified slag layer is formed on the surface of the refractory layer of the water-cooled wall in the gasification section, realizing slag resistance with slag; the ironmaking tail gas, high-temperature molten iron and slag flow to the settling separator through the outlet in the center of the conical head of the gasification section. The residual iron ore powder and carbon powder are kept warm and further undergo a reduction reaction. The reduced ironmaking tail gas at 1300-1700℃ is discharged from the top side of the settling separator and is drawn into the fluidized reduction reactor for high-iron red mud reduction magnetization; after the high-temperature molten iron and slag settle and separate, the slag is discharged through the slag outlet, and the high-temperature molten iron is discharged through the siphon-type molten iron outlet, which can maintain a stable molten iron-slag interface height.

[0016] The oxidant in the Y-type fluidized bed gasification reduction blast furnace is a mixture of water vapor and oxygen, air or oxygen-enriched air with an oxygen content greater than 21%, wherein the volume content of water vapor is 0-40%.

[0017] The features of the present invention will be described in detail through embodiments. Attached Figure Description

[0018] Appendix Figure 1 This is a schematic diagram of the present invention. (See attached diagram.) Figure 1 The drawing is defined as follows:

[0019] 1. Slurry pump 2. Flue gas distributor 3. Reactive distillation column 4. Filter press 5. Mixing slurry pump 6. Water washing desalination tower 7. Soft water distributor 8. Dehydration filter press 9. Combustion chamber 10. Fluidized drying tower 11. Drying gas-solid separator 12. Fluidized reduction reactor 13. Reduction reaction gas-solid separator 14. Cooler 15. Magnetic separator 16. Mixing bin 17. Y-type fluidized bed gasification reduction blast furnace 18. Settling separator 19. Top nozzle 20. Side nozzle 21. Ironmaking tail gas outlet 22. Iron tapping port 23. Slag outlet 24. Emergency treatment port.

[0020] A. Purified flue gas B. Washing brine C. Magnetic separation residue D. High-speed iron red mud E. Combustion flue gas F. Soft water G. Pulverized coal H. Air

[0021] The process features of the present invention will be described in detail below with reference to the accompanying drawings and embodiments. Detailed Implementation

[0022] In this embodiment, high-iron red mud D at 10-100℃ is pumped to the top of a reactive distillation column (3) via a mud pump (1). It comes into countercurrent contact with mixed flue gas at 30-180℃ introduced from the flue gas distributor (2) at the bottom of the column through a cross-flow tray or packing with 1-30 theoretical plates. The ratio of mixed flue gas to red mud slurry feed is 500-3000:1 (volume ratio). In the reactive distillation column (3), the acidic gases CO2, SOx, and NOx in the flue gas react with NaO, KO, and their alkaline salts in the slurry for efficient reactive distillation. SOx and NOx mainly react with insoluble alkaline substances in the lower part of the column, while CO2 mainly reacts with soluble alkaline substances in the upper part of the column, reducing the pH value of the red mud slurry from 11. -14 drops to no more than 8, purified flue gas A is discharged from the top of the reactive distillation tower (3), and the dealkalized and carbonized high-iron red mud slurry flows out from the bottom of the reactive distillation tower (3) and is desalinated by the filter press (4); the dehydrated high-iron red mud slurry is diluted again with part of the washing brine B and then pumped to the top of the water washing desalination tower (6) by the mixing mud pump (5), and is washed and desalinated by the soft water introduced by the soft water distributor (7) in a countercurrent flow. Part of the washing brine B flowing out from the top of the water washing desalination tower (6) is used to dilute the dehydrated red mud slurry and part is mixed with the concentrated brine and sent back to the alumina extraction section; the desalinated red mud slurry flowing out from the bottom of the water washing desalination tower (6) is dehydrated by the dehydration filter press (8) and sent to the fluidized drying tower (10), and the reduction tail gas is in the combustion chamber ( 9) After being supplemented by air H, it is also sent to the bottom of the fluidized drying tower (10) for fluidized heating and drying. The dried tail gas obtained by the drying gas-solid separator (11) at the top of the fluidized drying tower (10) is mixed with the combustion flue gas E and sent to the bottom of the reactive distillation tower (3). The dried desalted high-iron red mud obtained by gas-solid separation at the top of the fluidized drying tower (10) is sent to the fluidized reduction reactor (12) and undergoes a reduction magnetization reaction with the reduction ironmaking tail gas at 1300-1700℃. The reduction tail gas obtained by the reduction reaction gas-solid separator (13) at the top of the fluidized reduction reactor (12) is supplemented by combustion and used as the fluidized drying gas of the fluidized drying tower (10). The gas-solid separation obtained at the top of the reduction fluidized reactor (13) is... After being cooled by the reducing red mud cooler (14), the refined iron ore powder is then magnetically separated and recovered by the magnetic separator (15). The refined iron ore powder and coal powder are mixed in the mixing bin (16) and then fed into the Y-type fluidized bed gasification reduction ironmaking furnace (17) with an oxidant. In-situ gasification reduction ironmaking is carried out at 1300-1700℃. The high-temperature molten iron, slag and reducing ironmaking tail gas flow downward into the settling separator (18) at the bottom of the Y-type fluidized bed gasification reduction ironmaking furnace (17). After settling and stratification, molten iron is obtained from the tapping iron outlet (22), slag is obtained from the slag outlet (23) and ironmaking tail gas is obtained from the ironmaking tail gas outlet (21). The ironmaking tail gas is sent back to the fluidized reduction reactor (12), and the molten iron and slag are discharged as products.

[0023] The reactive distillation column (3) is a cross-flow structure without downcomers. A red mud slurry distributor is installed at the top of the column. The spacing between the cross-flow trays is 250-900 mm. A combustion flue gas distributor (2) is installed at the bottom of the column. The top of the column is the flue gas outlet, and the bottom of the column is the red mud slurry outlet. The CO2 content in the combustion flue gas is 12%-25%, SO2 content ... x Content ranges from 0-50000 ppm, NO x The content is 0-3000 ppm, and the flow velocity of the flue gas in the reactive distillation column (3) is 0.5-3.0 m / s. The concentration of the red mud slurry is 5%-60% by mass, and the spray density in the reactive distillation column (3) is 5-120 m³ / s. 3 / (m 2 •h).

[0024] The water washing desalination tower (6) is a cross-flow plate tower, a packed tower or an empty tower.

[0025] The fluidized drying tower (10) is a bubbling fluidized bed, a turbulent fluidized bed, or a riser conveying bed, and the fluidized drying temperature is 100~180℃.

[0026] The fluidized reduction reactor (12) is a pulse riser reactor, riser conveying bed, bubbling fluidized bed or turbulent fluidized bed. The reduction magnetization reaction temperature is 700-1300℃. The purity of the refined iron ore powder from magnetic separation is 40%-95%. The magnetic separation residue is used as a raw material for soil remediation agent, road material or building ceramic material.

[0027] The upper part of the Y-type fluidized bed gasification reduction blast furnace (17) is a cylindrical gasification section, and the lower part is a cylindrical settling separator (18). The gasification section and the settling separator (18) are in an inverted T-shaped structure. The gasification section adopts a water-cooled wall refractory lining layer. A downward spray top nozzle (19) is provided at the top, and more than 3 side nozzles (20) are provided along the circumference in the upper middle part. The nozzles are distributed in an inverted Y-shaped structure. The side nozzles have an angle of -15° to 15° with the horizontal direction and an angle of -5° to 75° with the radial direction. The settling separator (18) adopts a heat-insulating lining. The bottom is provided with a slag outlet (23), a siphon-type iron tapping outlet (22), and an emergency treatment port (24). The top side is provided with an ironmaking tail gas outlet (21), and the emergency treatment port (24) is provided at the bottom of the settling separator to ensure that the gas is vented in case of shutdown or emergency.

[0028] The operation of the Y-type fluidized bed gasification reduction ironmaking furnace (17) involves mixing fine iron ore powder and coal powder at a C:Fe2O3 ratio of 1:1.1-4.0 and feeding them into the mixing bin (16). The iron-coal powder mixture from the mixing bin (16) and the gasifying agent are injected into the gasification section through the top nozzle (19) and the radially inclined side nozzle (20) of the Y-type fluidized bed gasification reduction ironmaking furnace (17), and gasified and reduced at a temperature of 1300-1700℃. The top nozzle (19) and the side nozzle (20) generate multiple jets that collide with each other in the center of the furnace to form a Y-shaped rotating impact high-temperature reaction zone, which ignites each other and strengthens the gasification reduction reaction. The iron coke residue is thrown against the furnace wall of the gasification section and swirls downward. The iron coke residue remains in the gasification section. The reaction time is extended by more than 20 times, and a solidified slag layer is formed on the surface of the refractory layer of the water-cooled wall in the gasification section, so as to achieve slag resistance with slag. The tail gas of ironmaking, high-temperature molten iron and slag flow to the settling separator (18) through the outlet in the center of the conical head of the gasification section. The residual iron ore powder and carbon powder are kept warm and further undergo reduction reaction. The tail gas of ironmaking at 1300-1700℃ is discharged from the tail gas outlet (21) on the top side of the settling separator (18) and is drawn into the fluidized reduction reactor (12) for high-iron red mud reduction magnetization. After the high-temperature molten iron and slag settle and separate, the slag is discharged through the slag outlet, and the high-temperature molten iron is discharged through the siphon-type iron outlet (22) and can maintain a stable iron-slag interface height.

[0029] The oxidant of the Y-type fluidized bed gasification reduction blast furnace (17) is a mixture of water vapor and oxygen, air or oxygen-enriched air with more than 21% oxygen, wherein the volume content of water vapor is 0-40%.

[0030] The reactive distillation dealkali removal, carbon fixation, and reduction ironmaking process for high-iron red mud provided by this invention achieves graded utilization of acidic gases in flue gas according to their reactivity through a reactive distillation tower. This efficiently and cost-effectively solves the problem of removing insoluble alkaline substances from high-iron red mud in a low-cost and efficient manner. The dealkali removal rate is increased from the usual 50% to 98%, and the carbon fixation amount is increased from less than 40 kg CO2 / ton of 30% red mud to more than 150 kg CO2 / ton of 30% red mud. After dealkali removal and carbon fixation, the high-iron red mud is reduced and magnetically separated by ironmaking tail gas and reduced in situ for ironmaking. The purity of iron ore powder is increased by more than 30%, the iron recovery rate reaches no less than 99%, the energy consumption of ironmaking is reduced by more than 50%, and the cost is reduced by 500-1000 yuan / ton of iron, creating conditions for the high-value utilization of high-iron red mud resources.

Claims

1. The high-speed iron red mud reactive distillation dealkalization and carbon fixation and reduction ironmaking process is characterized by: High-iron red mud slurry at 10-100℃ is pumped to the top of a reactive distillation column, where it comes into countercurrent contact with mixed flue gas at 30-180℃ introduced from the bottom of the column via a cross-flow tray or packing with 1-30 theoretical plates. The feed ratio of the mixed flue gas to the high-iron red mud slurry is 500-3000:1 (volume ratio). The CO2 and SO2 in the flue gas within the reactive distillation column... x and NO x Acidic gases undergo efficient reactive distillation with Na₂O, K₂O, and their basic salts in the slurry, producing SO₂. x and NO x The reaction mainly occurs at the bottom of the column with insoluble alkaline substances, while CO2 mainly reacts with soluble alkaline substances at the top of the column, reducing the pH value of the red mud slurry from 11-14 to no more than 8. The purified flue gas is discharged from the top of the reactive distillation column, and the de-alkali and carbon-fixed high-iron red mud slurry flows out from the bottom of the reactive distillation column and is dehydrated with concentrated brine. The dehydrated high-iron red mud slurry is diluted again with some wash brine and then pumped to the top of the water washing desalination column for countercurrent water washing desalination. Part of the wash brine flowing out from the top of the water washing desalination column is used to dilute the dehydrated red mud slurry, and part is mixed with concentrated brine and sent back to the alumina extraction section. The desalinated red mud slurry flowing from the bottom of the water-washing desalination tower is dehydrated and sent to a fluidized bed dryer. It is then heated and fluidized by the reduction tail gas after supplemental combustion. The dried tail gas obtained from gas-solid separation at the top of the fluidized bed dryer is mixed with the combustion flue gas and sent to the bottom of the reactive distillation tower. The dried desalinated high-iron red mud obtained from gas-solid separation at the top of the fluidized bed dryer is sent to a fluidized reduction reactor, where it undergoes a reduction and magnetization reaction with ironmaking tail gas at 1300-1700℃. The reduction tail gas obtained from gas-solid separation at the top of the fluidized reduction reactor is used as the fluidized bed drying gas after supplemental combustion to recover heat. The reduced red mud obtained from the gas-solid separation at the top of the fluidized bed reduction reactor is cooled and then magnetically separated to recover refined iron ore powder. The refined iron ore powder and coal powder are mixed and fed into the Y-type fluidized bed gasification reduction blast furnace with an oxidant. In-situ gasification reduction blast furnace is carried out at 1300-1700℃. The high-temperature molten iron, slag and blast furnace tail gas flow downward into the settling separator at the bottom of the Y-type fluidized bed gasification reduction blast furnace. After settling and stratification, high-temperature molten iron, slag and blast furnace tail gas are obtained from different outlets. The blast furnace tail gas is sent back to the fluidized bed reduction reactor, and the high-temperature molten iron and slag are discharged as products.

2. The high-speed iron red mud reactive distillation dealkalization and carbon fixation and reduction ironmaking process according to claim 1, characterized in that... The reactive distillation column is a cross-flow structure without downcomers. A high-iron red mud slurry distributor is installed at the top of the column. The tray spacing of the cross-flow column is 250-900mm. A mixed flue gas distributor is installed at the bottom of the column. The top of the column is the purified flue gas outlet, and the bottom of the column is the dealkalized and carbonized high-iron red mud slurry outlet.

3. The high-speed iron red mud reactive distillation dealkali removal and carbon fixation and reduction ironmaking process according to claim 1, characterized in that... The CO2 content in the combustion flue gas is 12%-25%, SO2 content is 25%. x Content ranges from 0-50000 ppm, NO x The content is 0-3000 ppm, and the flue gas velocity in the reactive distillation column is 0.5-3.0 m / s.

4. The high-iron red mud reactive distillation dealkalization and carbon fixation and reduction ironmaking process according to claim 1, characterized in that... The mass concentration of the high-speed iron red mud slurry is 5%-60%, and the spray density in the reactive distillation column is 5-120 m³ / h. 3 / (m 2 •h).

5. The high-speed iron red mud reactive distillation dealkalization and carbon fixation and reduction ironmaking process according to claim 1, characterized in that... Water washing desalination towers can be cross-flow plate towers, packed towers, or empty towers.

6. The high-speed iron red mud reactive distillation dealkalization and carbon fixation and reduction ironmaking process according to claim 1, characterized in that... The fluidized bed drying tower is a bubbling fluidized bed, a turbulent fluidized bed, or a riser conveying bed, and the fluidized drying temperature is 100~180℃.

7. The high-speed iron red mud reactive distillation dealkalization and carbon fixation and reduction ironmaking process according to claim 1, characterized in that... The fluidized reduction reactor is a pulse riser reactor, riser conveying bed, bubbling fluidized bed or turbulent fluidized bed. The reduction magnetization reaction temperature is 700-1300℃. The purity of the refined iron ore powder from magnetic separation is 40%-95% (by mass). The magnetic separation residue is used as a raw material for soil remediation agents, road materials or building ceramic materials.

8. The high-speed iron red mud reactive distillation dealkalization and carbon fixation and reduction ironmaking process according to claim 1, characterized in that... The upper part of the Y-type fluidized bed gasification reduction blast furnace is a cylindrical gasification section, and the lower part is a cylindrical settling separator. The gasification section and settling separator have an inverted T-shaped structure. The gasification section adopts a water-cooled refractory lining layer, with a bottom-spraying top nozzle at the top and more than three side nozzles along the circumference in the upper middle part. The nozzles are distributed in an inverted Y-shaped structure. The side nozzles have an angle of -15° to 15° with the horizontal direction and an angle of -5° to 75° with the radial direction. The settling separator adopts a heat-insulating lining, and has a slag outlet, a siphon-type iron tapping port, and an emergency treatment port at the bottom. The ironmaking tail gas outlet is located on the top side. The emergency treatment port at the bottom of the settling separator ensures venting in case of shutdown or emergency.

9. The high-speed iron red mud reactive distillation dealkali removal and carbon fixation and reduction ironmaking process according to claim 8, characterized in that... The operation of the Y-type fluidized bed gasification reduction blast furnace involves uniformly mixing fine iron ore powder and pulverized coal at a C:Fe2O3 ratio of 1:1.1-4.0 and feeding the mixture into a mixing bin. The iron-coal mixture from the mixing bin, along with the oxidant, is injected into the gasification section through the top nozzle and radially inclined side nozzles of the Y-type fluidized bed gasification reduction blast furnace, where gasification and reduction occur at a temperature of 1300-1700℃. Multiple jets generated by the top and side nozzles collide with each other at the center of the furnace, forming a Y-shaped rotating impact high-temperature reaction zone. This mutual ignition enhances the gasification and reduction reaction. Iron coke residue is thrown against the furnace wall of the gasification section, swirling downwards. The iron coke residue remains and reacts within the gasification section. The time is extended by more than 20 times, and a solidified slag layer is formed on the surface of the refractory layer of the water-cooled wall in the gasification section, realizing slag resistance with slag; the ironmaking tail gas, high-temperature molten iron and slag flow to the settling separator through the outlet in the center of the conical head of the gasification section. The residual iron ore powder and carbon powder are kept warm and further undergo a reduction reaction. The ironmaking tail gas at 1300-1700℃ is discharged from the top side of the settling separator and is drawn into the fluidized reduction reactor for high-iron red mud reduction magnetization; after the high-temperature molten iron and slag settle and separate, the slag is discharged through the slag outlet, and the high-temperature molten iron is discharged through the siphon-type iron outlet and can maintain a stable iron-slag interface height.

10. The high-speed iron red mud reactive distillation dealkalization and carbon fixation and reduction ironmaking process according to claim 1, characterized in that... The oxidant in the Y-type fluidized bed gasification reduction blast furnace is a mixture of water vapor and oxygen, air or oxygen-enriched air with an oxygen content greater than 21%, wherein the volume content of water vapor is greater than 0% and not greater than 40%.

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