Red mud reduction, magnetic separation and recovery device and process based on chemical chain gasification

Abstract

The invention discloses a red mud reduction, magnetic separation and recovery device and process based on chemical looping gasification. The device comprises a chemical looping gasification device, a red mud feeder, a bag-type dust collector and a magnetic separator, the chemical chain gasification device comprises an air reactor, a first cyclone separator, a fuel reactor, a solid fuel feeder and a second cyclone separator, wherein the upper part of the air reactor is connected with a feed port of the first cyclone separator, a discharge port of the first cyclone separator is connected with the upper part of the combustion reactor, and the upper part of the fuel reactor is connected with a feed port of the second cyclone separator; the top of the second cyclone separator is connected with the bag-type dust collector through a fuel reactor tail flue, and the magnetic separator is connected with an ash discharge port of the bag-type dust collector; and the red mud feeder is connected with the bottom of the fuel reactor. Chemical looping gasification and red mud reduction roasting magnetic separation are combined, and iron element recovery and oxygen carrier replacement are achieved.

Description

Technical Field

[0001] This article relates to the field of chemical chain gasification and industrial solid waste resource utilization. The invention is a technical process for the recovery and reuse of iron metal by using a high-temperature gas-based reducing agent in a fuel reactor of chemical chain gasification to in-situ reduce and roast hematite with weak magnetic properties in high-iron content Bayer red mud to obtain magnetite or iron element with strong magnetic properties, and then using a weak magnetic separation process to recover magnetic iron minerals in red mud. Background Art

[0002] Red mud is an alkaline solid waste discharged during the industrial refining of alumina. In 2023, my country's red mud emissions exceeded 100 million tons. The process methods for producing alumina are mainly divided into sintering method and Bayer process. Among them, the Bayer process currently accounts for 90% of the world's production due to its low energy consumption. The alkalinity of more than 1 billion tons of stored red mud has a significant impact on the environment, and the resource utilization rate of red mud is less than 10% of the emissions, mainly concentrated in the preparation of building materials, for environmental governance, and the recovery of valuable metal resources. Bayer process red mud contains more than 30% of hematite components because the bauxite raw material contains iron. Recycling the iron element is an effective way to reduce and resource industrial solid waste.

[0003] The methods for recovering iron from red mud can be divided into physical iron selection, including direct magnetic separation and gravity separation, and chemical iron extraction, including acid leaching extraction and reduction roasting magnetic separation. Among them, direct magnetic separation requires high equipment requirements of strong magnetic field; gravity separation is negatively affected by the agglomeration and coating of red mud fine powder, and the iron separation efficiency is low. In the acid leaching extraction method, the alkaline components of red mud consume excessive acid, generating a large amount of waste liquid and waste residue, which is difficult to use for large-scale industrial production. The reduction roasting magnetic separation method is to reduce the weakly magnetic hematite to strongly magnetic magnetite or elemental iron by a reducing agent during the roasting process, and then weakly magnetic separation to recover the magnetic iron minerals. According to the type of reducing agent, it can be divided into solid carbonaceous reducing agent, gas-based reducing agent and biomass reducing agent. However, the temperature required for solid reduction is too high, and the energy consumption cost is not economical; the temperature of gaseous reduction is lower, and biomass gasification further reduces the cost of raw materials.

[0004] Chemical chaining combustion and gasification is an emerging environmentally friendly energy technology. Metal oxides are used as oxygen carriers to divide the redox process of fuel and air into two reactors for separate operations. The oxygen carrier is oxidized in the air reactor to carry lattice oxygen, and is reduced in the fuel reactor to release lattice oxygen. This cycle achieves continuous operation of chemical chaining combustion or gasification. After separating air and fuel, there is almost no nitrogen in the combustion flue gas or gasification products, which greatly increases the concentration of carbon dioxide and combustible gas, which is conducive to efficient carbon capture and subsequent Fischer-Tropsch synthesis of synthesis gas. In chemical chaining gasification, the fuel reactor is in a high-temperature reducing atmosphere, which is suitable for gas-based reduction roasting and magnetic separation to recover iron from red mud. The high hematite content of red mud can also serve as a part of the oxygen carrier and is reduced to magnetite or iron after a small amount of circulation. The reduced fine-grained red mud is recovered from the fly ash separated from the flue gas or synthesis gas of the fuel reactor.

[0005] Invention patent CN118127314A (invention name: A method for extracting metallic iron from high-iron red mud by efficient reduction in an electric furnace) discloses: after red mud is mixed with coal and dried into pellets, it is added to a 1600-degree Celsius electric furnace filled with molten scrap steel to directly reduce the iron in the red mud into molten steel, and the remaining slag phase is separated by melting. However, the reduction temperature of this invention is too high, the energy consumption is high, and additional coal and carbon injection are required to maintain a reducing atmosphere, resulting in an overall high cost and difficulty in large-scale industrial application. Summary of the invention

[0006] The following is a summary of the subject matter described in detail herein. This summary is not intended to limit the scope of the claims.

[0007] In view of the use of an additional gasifier to prepare a gaseous reducing agent in the red mud reduction roasting and magnetic separation process to recover iron, as well as the raw material, equipment and energy consumption costs caused by the reduction furnace required for high temperature conditions, the present application utilizes the fuel reactor of the chemical chain gasification process to have both high temperature and reducing syngas raw material conditions, combined with the high hematite content of Bayer red mud, which can be used as an oxygen carrier, and the small particle size of red mud powder, and uses high-iron Bayer red mud powder as part of the oxygen carrier in the chemical chain gasification process, and feeds it into the fuel reactor for in-situ high-temperature reduction to obtain magnetite or iron element, and after a short cycle, the fly ash is discharged with the flue gas to obtain reduced red mud for weak magnetic separation to recover the iron element in the red mud. The present application organically combines the two environmentally friendly processes of chemical chain gasification and red mud reduction roasting and magnetic separation, achieving low-energy and low-cost recovery of iron elements in red mud and low-cost replacement of oxygen carriers in chemical chain gasification.

[0008] The first aspect of the present application provides a red mud reduction magnetic separation recovery device based on chemical linking gasification, comprising: a chemical linking gasification device, a red mud feeder, a bag filter and a magnetic separator; the chemical linking gasification device comprises: an air reactor, a first cyclone separator, a fuel reactor solid fuel feeder and a second cyclone separator;

[0009] Wherein, the upper part of the air reactor is connected to the feed port of the first cyclone separator, the discharge port of the first cyclone separator is connected to the upper part of the combustion reactor, the upper part of the fuel reactor is connected to the feed port of the second cyclone separator, the top of the second cyclone separator is connected to the bag filter through the tail flue of the fuel reactor, and the magnetic separator is connected to the ash discharge port of the bag filter; the red mud feeder is connected to the bottom of the fuel reactor, and the solid fuel feeder is connected to the bottom of the fuel reactor and the red mud feeder is located above the solid fuel feeder.

[0010] In an exemplary embodiment, the chemical chain gasification device also includes: a first return material return device, a second return material return device, a third return material return device and an oxygen carrier feeder; wherein the oxygen carrier feeder is connected to the bottom of the air reactor, and the first return material return device is connected to the middle of the fuel reactor and the bottom of the air reactor; the discharge port leg of the first cyclone separator is connected to the upper part of the fuel reactor through the second return material return device; the discharge port leg of the second cyclone separator is connected to the bottom of the fuel reactor through the third return material return device.

[0011] In an exemplary embodiment, the upper portion of the air reactor is connected to one end of a horizontal flue of the air reactor at the top through an air reactor riser, and the other end of the horizontal flue of the air reactor is connected to a feed port of the first cyclone separator.

[0012] In an exemplary embodiment, the upper portion of the fuel reactor is connected to one end of a horizontal flue of the fuel reactor at the top through a fuel reactor riser, and the other end of the horizontal flue of the fuel reactor is connected to a feed port of the second cyclone separator.

[0013] In an exemplary embodiment, the chemical chaining gasification device further includes a compressor, which is connected to the bag filter and is used to compress high-concentration carbon dioxide and synthesis gas generated during the gasification process.

[0014] In an exemplary embodiment, the ash discharge port is disposed at the lower portion of the bag-type dust collector, and the compressor is connected to the gas outlet at the upper portion of the bag-type dust collector.

[0015] In an exemplary embodiment, a first gas outlet is further provided at the top of the first cyclone separator, and the first gas outlet is connected to the tail flue of the air reactor for discharging nitrogen generated in the air reactor.

[0016] In an exemplary embodiment, a second gas outlet is further provided on the top of the second cyclone separator, and the second gas outlet is connected to the bag filter through a tail flue of the fuel reactor.

[0017] In an exemplary embodiment, the air reactor is a fast bed, and an air inlet is disposed at the bottom of the air reactor for introducing air as fluidizing air.

[0018] In an exemplary embodiment, the fuel reactor is a turbulent bed, and the bottom of the fuel reactor is provided with an inlet for water vapor and recycled flue gas for introducing water vapor and recycled flue gas as fluidizing air.

[0019] In an exemplary embodiment, the bottoms of the first return material container, the second return material container, and the third return material container are respectively provided with steam inlets for introducing steam from an external steam boiler as fluidizing air.

[0020] In an exemplary embodiment, the solid fuel feeder and the red mud feeder are both screw feeders.

[0021] In an exemplary embodiment, the magnetic separator is a weak magnetic separator.

[0022] The second aspect of the present application provides a red mud reduction magnetic separation recovery process based on chemical linking gasification, which is implemented by the above-mentioned red mud reduction magnetic separation recovery device based on chemical linking gasification, comprising the following steps:

[0023] S1. Pretreatment of red mud raw materials;

[0024] S2. Chemical chain gasification to produce synthesis gas;

[0025] S3. Input and reduction of red mud;

[0026] S4. Separation of reduced red mud; and

[0027] S5. Magnetic separation to recover iron.

[0028] In an exemplary embodiment, the pretreatment of the red mud raw material in step S1 includes: selecting a red mud raw material with a ferric oxide content of more than 30%, drying (for example, air drying or sun drying) and crushing the red mud raw material to obtain red mud powder. The red mud raw material is derived from solid waste discharged from the Bayer process of refining alumina. Since the Bayer process red mud is discharged in the form of mud, the original red mud accumulated in the dam after treatment has a high water content and is in the form of mud blocks.

[0029] In an exemplary embodiment, in step S1, the particle size of the red mud powder is 5-50 μm.

[0030] In an exemplary embodiment, step S2 of chemical chaining gasification to produce synthesis gas includes: starting and operating the chemical chaining gasification device (for example, after ignition, heating, adding oxygen carriers, switching flue gas circulation, etc.) to a self-heating stable maintenance stage, adjusting the equivalence ratio of air to solid fuel and the oxygen carrier circulation volume to obtain a nitrogen-free, highly combustible, high-carbon dioxide synthesis gas.

[0031] In an exemplary embodiment, the particle size of the oxygen carrier is 150-350 μm.

[0032] In an exemplary embodiment, in step S2, the solid fuel is coal or biomass.

[0033] In an exemplary embodiment, in step S2, the bottom temperature of the fuel reactor is 850-950°C, and the operating pressure of the fuel reactor is 0.1-1 MPa.

[0034] In an exemplary embodiment, in step S2, the operating temperature of the air reactor is 900°C-1100°C.

[0035] In an exemplary embodiment, the input and reduction of red mud in step S3 includes: inputting the red mud powder prepared in step S1 into the bottom of the high-temperature fuel reactor of the chemical looping gasification device, the red mud powder undergoes an oxidation-reduction reaction with the synthesis gas generated by gasification of the solid fuel, and the hematite in the red mud is reduced; specifically:

[0036] After the chemical chain gasification device in step S2 operates stably and continuously, the red mud powder prepared in step S1 is added to the high-temperature fuel reactor, and the red mud powder undergoes an oxidation-reduction reaction with the synthesis gas (such as carbon monoxide and hydrogen, etc.) generated by gasification of the solid fuel, and the hematite in the red mud is reduced to magnetic magnetite or even iron. At the same time, the red mud powder also provides lattice oxygen in the hematite, which can replace part of the oxygen carrier, or participate in a small amount of chemical chain circulation.

[0037] In an exemplary embodiment, the separation of the reduced red mud in step S4 includes: the reduced red mud powder is separated from the oxygen carrier by the second cyclone separator of the chemical looping gasification device, and enters the bag filter to be captured; specifically:

[0038] After the red mud powder is reduced to magnetite, the particle size of the red mud powder is much smaller than the particle size of the oxygen carrier (such as ilmenite, etc.). The reduced red mud powder is separated from the oxygen carrier by the second cyclone separator along with the fluidized flue gas, and enters the bag filter to be captured. In this process, the alkaline red mud powder can also absorb and remove acidic gases such as sulfur dioxide in the flue gas.

[0039] In an exemplary embodiment, step S4 further comprises: some particles with larger particle sizes in the reduced red mud powder enter the air reactor along with the oxygen carrier to participate in the chemical chain cycle;

[0040] Optionally, the red mud powder participating in the chemical chain cycle accounts for about 10% of the total red mud powder.

[0041] In an exemplary embodiment, step S5 of magnetic separation and iron recovery includes: the red mud powder captured by the bag filter is transported (for example, by a belt) into the magnetic separator for separation and recovery. The magnetic iron-containing components are separated from the tailings, and the tailings can be used to manufacture building materials or improve soil, etc.

[0042] In an exemplary embodiment, the iron recovery rate of the red mud reduction magnetic separation recovery process based on chemical linking gasification exceeds 80%.

[0043] Compared with the prior art, the process designed by this application mainly has the following technical advantages:

[0044] (1) Low energy consumption cost. There is no need to build a separate gasification furnace and high-temperature reduction furnace, and there is no need to provide additional solid or gaseous reducing agents. The high temperature and reducing atmosphere of the chemical chain gasification device can be directly used in situ, saving equipment and fuel expenses, and achieving economical reduction and roasting of red mud.

[0045] (2) Realize the resource utilization of red mud. Through reduction roasting and magnetic separation, the hematite in the red mud is reduced to magnetite or even iron and then separated and recovered. The magnetic separation tailings can be used to prepare building materials and improve soil, etc., realizing the high added value reduction and harmless resource reuse of red mud, which is friendly to the environment.

[0046] (3) Convenient for input and removal. Red mud powder can be continuously fed into the fuel reactor. Due to its small particle size, it can easily enter the flue gas and become fly ash without mixing with the original oxygen carrier. After the fly ash is separated by a cyclone and then removed by a bag filter, it quickly enters the weak magnetic separation to recover iron.

[0047] (4) Reduce the amount of oxygen carriers used. The hematite in red mud provides a portion of lattice oxygen, which reduces the need for oxygen carriers to transport lattice oxygen, reduces the amount of oxygen carriers circulated in chemical chain gasification, saves oxygen carrier costs, and does not affect the continuous and stable operation of chemical chain gasification.

[0048] In summary, the chemical chain gasification reduction red mud process has the advantages of low energy cost, resource utilization of red mud, convenient input and withdrawal, and reduced oxygen carrier usage. These advantages make the invention have a wide industrial application market in the application scenario of recovering iron from red mud.

[0049] This invention integrates chemical chain gasification and red mud reduction, and uses high temperature and synthesis gas to in-situ reduce red mud in chemical chain gasification and then recover iron by magnetic separation. This invention can reduce the energy consumption cost of reduction roasting, reduce the amount of industrial solid waste red mud, and utilize it harmlessly and resourcefully. It realizes the continuous feeding of red mud and the convenient discharge and weak magnetic separation to recover iron after the reduction reaction, saving the cost of oxygen carrier without affecting the stable operation of chemical chain gasification. The in-situ reduction of red mud in the chemical chain gasification process and the recovery of iron by magnetic separation can achieve large-scale industrial production.

[0050] Other features and advantages of the present application will be described in the following description, and partly become apparent from the description, or be understood by implementing the present application. Other advantages of the present application can be realized and obtained by the schemes described in the description and the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] The accompanying drawings are used to provide an understanding of the technical solution of the present application and constitute a part of the specification. Together with the embodiments of the present application, they are used to explain the technical solution of the present application and do not constitute a limitation on the technical solution of the present application.

[0052] Figure 1 Schematic diagram of the red mud reduction and magnetic separation recovery device based on chemical chain gasification. DETAILED DESCRIPTION

[0053] The present application describes multiple embodiments, but the description is exemplary rather than restrictive, and it is obvious to those skilled in the art that there may be more embodiments and implementations within the scope of the embodiments described in the present application. Although many possible feature combinations are shown in the drawings and discussed in the specific embodiments, many other combinations of the disclosed features are also possible. Unless specifically limited, any feature or element of any embodiment may be used in combination with any other feature or element in any other embodiment, or may replace any other feature or element in any other embodiment.

[0054] The present application includes and contemplates combinations of features and elements known to those of ordinary skill in the art. The embodiments, features and elements disclosed in the present application may also be combined with any conventional features or elements to form a unique invention scheme. Any features or elements of any embodiment may also be combined with features or elements from other invention schemes to form another unique invention scheme. Therefore, it should be understood that any feature shown and / or discussed in the present application may be implemented individually or in any appropriate combination. Therefore, except for the limitations made according to the attached claims and their equivalents, the embodiments are not subject to other restrictions. In addition, various modifications and changes may be made within the scope of protection of the attached claims.

[0055] In addition, when describing representative embodiments, the specification may have presented the method and / or process as a specific sequence of steps. However, to the extent that the method or process does not rely on the specific order of the steps described herein, the method or process should not be limited to the steps of the specific order described. As will be understood by those of ordinary skill in the art, other sequences of steps are also possible. Therefore, the specific sequence of the steps set forth in the specification should not be interpreted as a limitation to the claims. In addition, the claims for the method and / or process should not be limited to the steps of performing them in the order written, and those skilled in the art can easily understand that these sequences can be changed and still remain within the spirit and scope of the embodiments of the present application.

[0056] Example 1.

[0057] like Figure 1 As shown, a red mud reduction magnetic separation recovery device based on chemical chain gasification includes: a chemical chain gasification device, a red mud feeder X503, a bag filter S803 and a magnetic separation separator S804, wherein:

[0058] The chemical chain gasification device includes: an air reactor R101, a fuel reactor R102, an air reactor riser R104, a fuel reactor riser R103, a first cyclone separator V201, a second cyclone separator V202, a first return material device X250, a second return material device X201, a third return material device X202, an air reactor tail flue S801, a fuel reactor tail flue S802, a compressor S805, an oxygen carrier feeder X501, and a solid fuel feeder X502;

[0059] The first return material device X250 connects the middle part of the fuel reactor R102 and the bottom part of the air reactor R101; the upper part of the air reactor R101 is connected to one end of the horizontal flue of the air reactor at the top through the air reactor riser R104, and the other end of the horizontal flue of the air reactor is connected to the feed port of the first cyclone separator V201; the discharge port leg of the first cyclone separator V201 is connected to the upper part of the fuel reactor R102 through the second return material device X201; the upper part of the fuel reactor R102 is connected to one end of the horizontal flue of the fuel reactor at the top through the fuel reactor riser R103, and the other end of the horizontal flue of the fuel reactor is connected to the second cyclone separator V201. 02, the discharge leg of the second cyclone separator V202 is connected to the bottom of the fuel reactor R102 through the third return device X202; the oxygen carrier feeder X501 is connected to the bottom of the air reactor R101; the solid fuel feeder X502 is connected to the bottom of the fuel reactor R102; the top of the first cyclone separator V201 is provided with a first gas outlet, and the first gas outlet is connected to the tail flue S801 of the air reactor, for discharging the nitrogen generated by the air reactor; the top of the second cyclone separator V202 is provided with a second gas outlet, and the second gas outlet is connected to the bag filter S803 through the tail flue S802 of the fuel reactor.

[0060] The bag filter S803 is arranged at the end of the tail flue S802 of the fuel reactor, and the magnetic separator S804 is connected to the ash discharge port of the bag filter S803; the red mud feeder X503 is connected to the bottom of the fuel reactor R102 and is located above the solid fuel feeder X502; the magnetic separator S804 is a weak magnetic separator.

[0061] The chemical chain gasification device also includes a compressor S805, which is connected to the bag-type dust collector S803 and is used to compress the high-concentration carbon dioxide and synthesis gas generated during the gasification process; specifically, the ash discharge port is arranged at the lower part of the bag-type dust collector S803, and the compressor S805 is connected to the gas outlet at the upper part of the bag-type dust collector S803.

[0062] The air reactor R101 is a fast bed, and an air inlet is provided at the bottom of the air reactor R101 for introducing air as fluidizing air; the fuel reactor R102 is a turbulent bed, and an inlet for water vapor and recycled flue gas is provided at the bottom of the fuel reactor R102 for introducing water vapor and recycled flue gas as fluidizing air; water vapor is introduced into the bottom of the first recycler X250, the second recycler X201 and the third recycler X202 as fluidizing air.

[0063] The solid fuel feeder X502 and the red mud feeder X503 are both screw feeders.

[0064] Example 2.

[0065] A red mud reduction magnetic separation recovery process based on chemical linking gasification based on the device described in Example 1 comprises the following steps:

[0066] S1. Pretreatment of red mud raw materials;

[0067] Select red mud raw materials with a ferric oxide content of more than 30%, dry (for example, air dry or sun dry) the red mud raw materials and crush them into small particles to obtain red mud powder. The red mud raw materials come from solid waste discharged from the Bayer process of refining alumina. Since the Bayer process red mud is discharged in the form of mud, the original red mud accumulated in the dam after treatment has a high water content and is in the form of mud blocks; the red mud particle size is 5-50 μm;

[0068] S2. Chemical chaining gasification to produce syngas

[0069] The chemical chain gasification device is started, and after the steps of ignition, heating, oxygen carrier input, switching flue gas circulation, etc., it enters the self-heating and maintaining stable stage, and adjusts the equivalent ratio of air to solid fuel and the circulation amount of oxygen carrier to obtain nitrogen-free, highly combustible gas and high carbon dioxide synthesis gas; the particle size of the oxygen carrier is 150-350μm; the solid fuel is coal or biomass;

[0070] Input and reduction of S3 red mud

[0071] The red mud powder dried and crushed in step S1 is fed into the bottom of the fuel reactor R102 through the red mud feeder X503. In the high-temperature fuel reactor R102, the hematite component in the red mud powder undergoes an oxidation-reduction reaction with the synthesis gas generated by gasification of the solid fuel, and the hematite in the red mud powder is reduced to magnetite with magnetic properties or even iron. At the same time, the red mud powder also provides lattice oxygen, which can replace part of the oxygen carrier or participate in a small amount of chemical chain circulation.

[0072] Separation of S4 reduced red mud

[0073] The reduced red mud powder is separated from the oxygen carrier by the second cyclone separator V202 of the chemical linking gasification device and enters the bag filter S803 to be captured; specifically:

[0074] Since the red mud powder is reduced to magnetite, the particle size of the red mud powder is smaller than that of the oxygen carrier, and the reduced red mud powder easily enters the flue gas of the fuel reactor R102, is separated from the oxygen carrier in the second cyclone separator V202, and enters the bag filter S803 to be captured. Some red mud powder particles with larger particle sizes will enter the air reactor R101 with the oxygen carrier to carry out a small amount of chemical chain circulation. In this process, the alkaline red mud powder can also absorb and remove acidic gases such as sulfur dioxide in the flue gas; this part of the red mud powder participating in the chemical chain circulation accounts for about 10% of the total amount.

[0075] S5 magnetic separation to recover iron

[0076] The red mud powder captured by the bag filter S803 (for example, by a belt) is transported to the magnetic separator S804 for separation and recovery. The magnetic iron-containing components are separated from the tailings, and the tailings can be used to make building materials or improve soil. In this process, the iron recovery rate exceeds 80%.

[0077] Example 3.

[0078] In Example 2, step S2 chemical chaining gasification to produce synthesis gas includes the following steps:

[0079] S21 Pyrolysis-reduction reaction: The crushed solid fuel particles are fed into the fuel reactor R102 through the solid fuel feeder X502, and are fully mixed with the high-temperature oxygen carrier bed in the fuel reactor R102. The solid fuel particles are rapidly heated by the oxygen carrier to undergo a rapid pyrolysis reaction to release volatiles, wherein the bottom temperature of the fuel reactor R102 is 850-950°C, and the operating pressure of the fuel reactor R102 is 0.1-1MPa. The heat required in the pyrolysis process of the solid fuel is provided by the oxygen carrier, and the oxygen carrier also acts as an oxidant. Part of the coke or semi-coke generated by the pyrolysis reaction subsequently undergoes an oxidation reaction with the lattice oxygen released by the oxygen carrier to produce synthesis gas. In this process, the oxygen carrier is reduced to a reduced oxygen carrier, and part of the coke or semi-coke reacts with the gasifying agent water vapor to generate synthesis gas; the synthesis gas generated by the reaction, part of the unburned carbonaceous fuel, ash, the reduced red mud powder in Example 2, and a small amount of oxygen carrier are passed through the fuel reactor riser R10 3 enters the second cyclone separator V202 for gas-solid separation, and the unburned carbon and oxygen carrier particles are separated due to their large particle size and fall into the third recycler X202, and then sent back to the fuel reactor R102 for further conversion; the reduced red mud powder and ash in Example 2 are discharged with the flue gas due to their small particle size, and the flue gas exchanges heat with the circulating water around the fuel reactor R102 through the flue heating surface in the flue S802 at the tail of the fuel reactor; the steam boiler and the first recycler X25 0. The second recycle device X201, the third recycle device X202 and the fuel reactor R102 are connected to provide water vapor as fluidizing air for the first recycle device X250, the second recycle device X201, the third recycle device X202 and the fuel reactor R102; then the flue gas is separated into gas components and solids (including reduced red mud) in the bag filter S803, and the solids are transferred to the magnetic separator S804. The gas is upgraded by the compressor S805 to obtain the synthesis gas product;

[0080] S22 Oxidation reaction: The reduced oxygen carrier passes through the overflow pipe and enters the first recycle vessel X250, and is then sent to the air reactor R101 to contact with the air. The reduced oxygen carrier undergoes an oxidation reaction to release a large amount of heat, becoming an oxidized oxygen carrier. The particles themselves heat up while heating the air reactor R101. At this time, the operating temperature of the air reactor R101 is 900°C-1100°C. The oxidized oxygen carrier is blown to the top of the air reactor R101 and then enters the first cyclone separator V201 for gas-solid separation. The gas component is mainly high-concentration nitrogen. The oxidized oxygen carrier falls into the second recycle vessel X201 and is then sent to the fuel reactor R102, thus completing the redox cycle reaction of the oxygen carrier.

[0081] In the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0082] In addition, the terms "first", "second", etc. are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first", "second", etc. may explicitly or implicitly include at least one of the features.

[0083] In the description of the present application, “plurality” means at least two, for example, two, three, etc., unless otherwise clearly and specifically defined.

[0084] In this application, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed", etc. should be understood in a broad sense. For example, "connected" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0085] In the present application, unless otherwise clearly specified and limited, a first feature being “above” or “below” a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being “above”, “above”, and “above” a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being “below”, “below”, and “below” a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0086] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example" or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0087] Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limitations on the present application. Ordinary technicians in this field can change, modify, replace and modify the above embodiments within the scope of the present application.

Claims

1. A red mud reduction magnetic separation recovery device based on chemical chain gasification, characterized in that: include: A chemical chain gasification device, a red mud feeder, a bag filter and a magnetic separator; the chemical chain gasification device comprises: an air reactor, a first cyclone separator, a fuel reactor, a solid fuel feeder and a second cyclone separator; Wherein, the upper part of the air reactor is connected to the feed port of the first cyclone separator, the discharge port of the first cyclone separator is connected to the upper part of the combustion reactor, the upper part of the fuel reactor is connected to the feed port of the second cyclone separator, the top of the second cyclone separator is connected to the bag filter through the tail flue of the fuel reactor, and the magnetic separator is connected to the ash discharge port of the bag filter; the red mud feeder is connected to the bottom of the fuel reactor, and the solid fuel feeder is connected to the bottom of the fuel reactor and the red mud feeder is located above the solid fuel feeder.

2. The device according to claim 1, characterized in that The chemical chain gasification device further comprises: a first material return device, a second material return device, a third material return device and an oxygen carrier feeder; Among them, the oxygen carrier feeder is connected to the bottom of the air reactor, the first return feeder is connected to the middle part of the fuel reactor and the bottom of the air reactor; the discharge leg of the first cyclone separator is connected to the upper part of the fuel reactor through the second return feeder; the discharge leg of the second cyclone separator is connected to the bottom of the fuel reactor through the third return feeder.

3. The device according to claim 2, characterized in that The upper part of the air reactor is connected to one end of the horizontal flue of the air reactor at the top through an air reactor riser, and the other end of the horizontal flue of the air reactor is connected to the feed port of the first cyclone separator; the upper part of the fuel reactor is connected to one end of the horizontal flue of the fuel reactor at the top through a fuel reactor riser, and the other end of the horizontal flue of the fuel reactor is connected to the feed port of the second cyclone separator.

4. The device according to claim 2 or 3, characterized in that The chemical chain gasification device further comprises a compressor, and the compressor is connected to the bag filter; Optionally, the ash discharge port is arranged at the lower part of the bag-type dust collector, and the compressor is connected to the gas outlet at the upper part of the bag-type dust collector.

5. The device according to claim 2 or 3, characterized in that: The top of the first cyclone separator is also provided with a first gas outlet, and the first gas outlet is connected to the tail flue of the air reactor; The top of the second cyclone separator is also provided with a second gas outlet, and the second gas outlet is connected to the bag filter through the tail flue of the fuel reactor.

6. The device according to claim 2 or 3, characterized in that: The air reactor is a fast bed, and an air inlet is provided at the bottom of the air reactor for introducing air as fluidizing air; and / or The fuel reactor is a turbulent bed, and the bottom of the fuel reactor is provided with an inlet for water vapor and recycled flue gas for introducing water vapor and recycled flue gas as fluidizing air; and / or The bottoms of the first return material container, the second return material container and the third return material container are respectively provided with steam inlets for introducing steam from an external steam boiler as fluidizing air.

7. The device according to claim 2 or 3, characterized in that The solid fuel feeder and the red mud feeder are both screw feeders; and / or The magnetic separator is a weak magnetic separator.

8. A red mud reduction magnetic separation recovery process based on chemical chain gasification, characterized in that: The method is realized by a red mud reduction magnetic separation recovery device based on chemical linking gasification according to any one of claims 1 to 7, comprising the following steps: S1. Pretreatment of red mud raw materials; Selecting a red mud raw material with a ferric oxide content of more than 30%, drying and crushing the red mud raw material to obtain red mud powder; S2. Chemical chain gasification to produce synthesis gas; The chemical chain gasification device is started and operated to the stage of maintaining self-heating stability, and the equivalent ratio of air to solid fuel and the circulation amount of oxygen carrier are adjusted to obtain nitrogen-free, highly combustible gas and high carbon dioxide synthesis gas; S3. Input and reduction of red mud; The red mud powder prepared in step S1 is added to the bottom of the high-temperature fuel reactor of the chemical looping gasification device, and the red mud powder undergoes an oxidation-reduction reaction with the synthesis gas generated by gasification of the solid fuel, and the hematite in the red mud is reduced; S4. Separation of reduced red mud; The reduced red mud powder is separated from the oxygen carrier by the second cyclone separator of the chemical looping gasification device and enters the bag filter to be captured; S5. Magnetic separation to recover iron The red mud powder captured by the bag filter is transported to the magnetic separator for separation and recovery.

9. The process according to claim 8, characterized in that In step S1, the particle size of the red mud powder is 5-50 μm.

10. The process according to claim 8 or 9, characterized in that The particle size of the oxygen carrier is 150-350 μm; and / or In step S2, the solid fuel is coal or biomass.

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