A method for resource utilization of red mud and carbon dioxide

Abstract

This invention provides a method for the resource utilization of red mud and carbon dioxide, relating to the technical field of red mud recycling. The method involves: crushing red mud to obtain red mud particles; adding an inorganic salt solution containing carbonate ions and water to the red mud particles, stirring to obtain a red mud slurry; placing the red mud slurry in a reactor with a distributed electric field, introducing CO2 gas and stirring to induce a carbonization reaction, followed by solid-liquid separation to obtain carbonized red mud precipitate and an inorganic salt solution; sieving the carbonized red mud precipitate to obtain coarse-grained carbonized red mud for use as ironmaking raw material or manufactured sand, and fine carbonized mud for separating aluminum and silicon concentrates; and recycling the inorganic salt solution after passing CO2 through it to crystallize sodium bicarbonate. This invention innovates a method to enhance the depth of carbonization, enabling efficient utilization of both the concentrate product obtained through indirect carbonization and the crystallized inorganic salt solution, facilitating large-scale industrial production and widespread application.

Description

Technical Field

[0001] This invention relates to the technical field of red mud recycling, and more particularly to a method for the resource utilization of red mud and carbon dioxide. Background Technology

[0002] my country is a major producer of alumina, generating nearly 150 million tons of red mud annually from steelmaking, with accumulated stockpiles exceeding 600 million tons. Currently, there is no ideal solution for its disposal or resource utilization. The primary method currently used is as a raw material for ironmaking, obtained through magnetic separation. However, the high alkali content of this magnetically separated red mud concentrate limits its applicability. In recent years, the use of red mud in the production of various building materials has shown promise for achieving comprehensive recycling and utilization of red mud.

[0003] Chinese patent CN116535065A discloses a red mud dealkali reduction system and method, which requires the operation of a high-cost hypergravity carbonization tank for the carbonization process. It utilizes the reaction of carbon dioxide, desulfurized gypsum and alkali in the red mud slurry, as well as the acidic substances produced by the bacterial liquid in the bacterial culture tank to neutralize the residual alkali in the carbonized and calcified red mud slurry. The utilization method is not efficient, the operation process is complicated, the products after red mud dealkali reduction cannot be effectively utilized, and the production cost is increased. The use of hypergravity field further increases the cost, and it is not suitable for industrial production.

[0004] In order to make better use of red mud, Chinese patent CN116410623A discloses a method for preparing carbonized modified red mud-based hydrophobic concrete coating. This method requires the participation of ultrafine red mud powder and ultrafine fly ash powder. The resulting carbonized modified red mud-based hydrophobic concrete coating has a low utilization rate of red mud, and the consumption of silane coupling agent is also high. Overall, the application range of the superhydrophobic coating on concrete surfaces is not large.

[0005] Although Chinese patent CN113896466A discloses a method for consolidating red mud based on carbonation reaction and the resulting carbonized product, the method involves mixing carbonized cementitious material with red mud to obtain a dry mixture; adding water to the dry mixture and mixing it to form a green body; and then carbonizing the green body to obtain the carbonized product. Obviously, this method requires a large amount of carbonized cementitious material, and the carbonization is only applied to the green body, resulting in a low carbonization depth and poor carbonization effect.

[0006] Chinese patent CN116283208A discloses a method for preparing high-strength building bricks using alumina red mud carbonization. This method requires adding activated fly ash and bottom blowing carbon dioxide for stirring and dealkalization, followed by carbon dioxide carbonization of the raw bricks. Obviously, this involves a second carbon dioxide carbonization process, which does not achieve deep carbonization. The operation process is complex, the utilization rate of red mud is low, the red mud bricks produced have a narrow application range, high cost, and low efficiency.

[0007] Chinese patent CN116081970A discloses a sintering method for carbonized red mud artificial aggregate and its preparation method. This method involves carbonizing and sintering cured red mud blanks to obtain carbonized red mud artificial aggregate. Not only is the operation process complicated, but the carbonization reaction also requires adjustment of air pressure and reaction time, resulting in high cost and low efficiency. The utilization rate of red mud is limited to replacing natural aggregates such as sand and stone as raw materials for concrete, rather than decomposing and recycling red mud and making it more effective in a wider range.

[0008] Chinese patent CN115215564A discloses a method and application of using wet carbonization to solidify heavy metals in red mud. The method involves repeatedly wet grinding red mud to make slurry, and then adding carbon dioxide to lower the pH to 7-8 to prepare a cementitious material for concrete production. Obviously, the wet grinding process will increase the impurity content of red mud and increase the production cost. Its application is to partially replace cement in concrete raw materials, and its scope of application is relatively narrow. Summary of the Invention

[0009] The technical problem to be solved by this invention is that current red mud recycling technologies have technical defects such as high cost, low utilization rate, complex preparation process, high operation difficulty, long process and low efficiency. Furthermore, the high cost of applying hypergravity fields, the partial substitution of concrete raw materials, and the difficulty in achieving deep carbonization due to the target of carbonization all prove this point. Therefore, existing technologies cannot comprehensively utilize red mud as a whole and are not suitable for industrial production.

[0010] To solve the above-mentioned technical problems, the present invention provides the following technical solution:

[0011] A method for the resource utilization of red mud and carbon dioxide, comprising the following steps:

[0012] S1. Break the red mud lumps to obtain red mud particles;

[0013] S2. Add an inorganic salt solution containing carbonate to the red mud particles in S1 to prepare a red mud slurry.

[0014] S3. Place the red mud slurry from S2 into a reactor with a distributed electric field, introduce CO2 gas and stir to induce carbonization reaction, and then separate the solid and liquid to obtain carbonized red mud precipitate and inorganic salt solution.

[0015] S4. The carbonized red mud precipitated in S3 is screened to obtain coarse carbonized red mud and fine carbonized mud. The coarse carbonized red mud is used as raw material for ironmaking, and the fine carbonized mud is separated by flotation to obtain aluminum concentrate and silicon concentrate.

[0016] S5. The inorganic salt solution of S3 is passed through CO2 to crystallize baking soda and then recycled as the inorganic salt solution of S2.

[0017] Preferably, the particle size of the red mud particles in S1 is -4.75 mm.

[0018] Preferably, the carbonate-containing inorganic salt solution in S2 includes at least one of sodium carbonate, lithium carbonate, potassium carbonate, and carbonate-containing industrial waste liquid, and the solid concentration of the red mud slurry is 2.15-693 g / L.

[0019] Preferably, the inorganic salt solution containing carbonate in S2 is an industrial waste liquid containing 2.3-56% carbonate, and the solid concentration of the red mud slurry is 2.15-693 g / L.

[0020] Preferably, the process parameters of the distributed electric field in reactor S3 are set such that the current density flowing through the slurry cross-section is 5-350 A / m. 2 .

[0021] Preferably, the CO2 gas in S3 is CO2-rich gas enriched from flue gas, which simultaneously achieves CO2 emission reduction, and the volume percentage of CO2 in the gas is 30-99.6%.

[0022] Preferably, the stirring in S3 includes mechanical stirring, electromagnetic stirring, or gas stirring.

[0023] Preferably, the induced carbonization time in S3 is 3-72 h.

[0024] Preferably, the solid-liquid separation in S3 is at least one of sedimentation, coagulation, and filtration.

[0025] Preferably, the coarse-grained carbonized red mud in S4 is composed of hematite, goethite and a small amount of quartz, with a particle size of 0.3-4.75 mm; the fine carbonized mud is mostly composed of boehmite, aluminum hydroxide and quartz, with a particle size not exceeding 0.3 mm.

[0026] Preferably, when the carbonized red mud in S4 is used as a raw material for ironmaking, the total iron content is 55-63% and the Na2O content is <0.3%; when the carbonized red mud is used as manufactured sand, it meets the Class II sand requirements of "Construction Sand" (GB / T 14684).

[0027] The inventor's technical principle:

[0028] This invention provides a method for the resource utilization of red mud and carbon dioxide. First, the red mud is crushed, and CO2 gas is introduced into the red mud slurry. An inorganic salt solution is used as an inducer to enhance the reaction between the red mud slurry and CO2 under the action of an electric field, and the slurry is stirred. An electric field is distributed in a steel container holding the inorganic salt solution, and current flows through the cross section of the slurry. After carbonization, the residue is separated from the inorganic salt solution by sedimentation, coagulation, filtration and other methods. The coarse carbonized red mud is screened out and used as manufactured sand, while the fine mud is used to separate calcite and magnesite. The inorganic salt solution is recycled.

[0029] In this invention, an inorganic salt solution containing carbonate ions is used as the inducing medium to induce indirect carbonation; indirect carbonation occurs in the presence of CO3 in activated calcium oxide, magnesium oxide, and an inorganic salt solution containing carbonate ions. 2- In between, CO2 gas introduced into an inorganic salt solution containing carbonate reacts with the solution to regenerate CO3. 2- Carbonization efficiency is significantly improved, and red mud can be comprehensively utilized as a whole.

[0030] The above technical solution has at least the following advantages compared with the existing technology:

[0031] The above-mentioned solution proposes a method for the resource utilization of red mud and carbon dioxide, which can solve the technical defects of existing red mud recycling technologies, such as high cost, low utilization rate, complex preparation process, high operation difficulty, long process and low efficiency, so that red mud can achieve the resource utilization of all components.

[0032] This invention enhances the reaction between traditional red mud slurry and CO2 under the action of an electric field by using an inorganic salt solution containing carbonate ions as an inducer. This transforms the direct carbonization of red mud with CO2 into indirect carbonization, effectively strengthening not only the carbonization depth of red mud but also significantly enhancing its stability and activity. This solves the technical problems of poor stability of red mud particles and the inability of the product to be directly used as raw material for ironmaking or manufactured sand.

[0033] The method for reusing red mud in this invention enables the effective utilization of both the prepared carbonized red mud precipitate and inorganic salt solution. The amount of red mud that can be utilized is higher than that used in the production of concrete, cement, and building bricks. Moreover, the process is not complicated, the operation is easy, the production cost is low, the process is short, and it is conducive to large-scale production.

[0034] In summary, compared with other traditional methods, the method of this invention innovates a method to enhance the carbonization depth in the reuse of red mud. The products and inorganic salt solutions obtained by the indirect carbonization method can be utilized efficiently, with a wide range of applications. The process is simple, and the utilization method is low-cost and highly efficient, which is conducive to large-scale industrial production and promotion. Attached Figure Description

[0035] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0036] Figure 1 This is a process flow diagram of a method for the resource utilization of red mud and carbon dioxide according to the present invention. Detailed Implementation

[0037] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the described embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0038] A method for the resource utilization of red mud and carbon dioxide, wherein the method for the resource utilization of red mud and carbon dioxide is combined with Figure 1 The following steps are required:

[0039] S1. Break the red mud lumps to obtain red mud particles;

[0040] S2. Add an inorganic salt solution containing carbonate to the red mud particles in S1 to prepare a red mud slurry.

[0041] S3. Place the red mud slurry from S2 into a reactor with a distributed electric field, introduce CO2 gas and stir to induce carbonization reaction, and then separate the solid and liquid to obtain carbonized red mud precipitate and inorganic salt solution.

[0042] S4. The carbonized red mud precipitated in S3 is screened to obtain coarse carbonized red mud and fine carbonized mud. The coarse carbonized red mud is used as raw material for ironmaking, and the fine carbonized mud is separated by flotation to obtain aluminum concentrate and silicon concentrate.

[0043] S5. The inorganic salt solution of S3 is passed through CO2 to crystallize baking soda and then recycled as the inorganic salt solution of S2.

[0044] Specifically, the red mud particles in S1 have a particle size of -4.75 mm.

[0045] Specifically, the carbonate-containing inorganic salt solution in S2 includes at least one of sodium carbonate, lithium carbonate, potassium carbonate, and carbonate-containing industrial wastewater, and the solid concentration of the red mud slurry is 2.15-693 g / L.

[0046] Specifically, the inorganic salt solution containing carbonate in S2 is an industrial waste liquid containing 2.3-56% carbonate, and the solid concentration of the red mud slurry is 2.15-693 g / L.

[0047] Specifically, the process parameters for the distributed electric field in reactor S3 need to be set so that the current density flowing through the slurry cross-section is 5-350 A / m. 2 .

[0048] Specifically, the CO2 gas in S3 is CO2-rich gas enriched from flue gas, achieving CO2 emission reduction simultaneously, with CO2 accounting for 30-99.6% of the gas volume.

[0049] Specifically, the stirring in S3 includes mechanical stirring, electromagnetic stirring, or gas stirring.

[0050] Specifically, the induced carbonization time in S3 is 3-72 h.

[0051] Specifically, in S3, solid-liquid separation includes at least one of sedimentation, coagulation, and filtration.

[0052] Specifically, the coarse-grained carbonized red mud in S4 is composed of hematite, goethite and a small amount of quartz, with a particle size of 0.3-4.75 mm; the fine carbonized mud is mostly composed of boehmite, aluminum hydroxide and quartz, with a particle size of no more than 0.3 mm.

[0053] Specifically, when S4 carbonized red mud is used as a raw material for ironmaking, the total iron content is 55-63% and the Na2O content is <0.3%; when carbonized red mud is used as manufactured sand, it meets the Class II sand requirements of "Construction Sand" (GB / T 14684).

[0054] Example 1

[0055] A method for the resource utilization of red mud and carbon dioxide, wherein the method for the resource utilization of red mud and carbon dioxide is combined with Figure 1 The following steps are required:

[0056] S1. 10 kg of untreated red mud from a certain area in Guangxi was crushed to obtain red mud particles with a particle size of -4.75 mm. After multiple tests, its main components, by mass percentage, are: TFe 9.13-28.35%, Al2O3 5.01-19.86%, SiO2 11.39-29.734%, Na2O 3.73-21.28%, Ca 3.26-19.95%.

[0057] S2. Add sodium carbonate industrial waste liquid containing 20% ​​carbonate and water to the red mud particles of S1, and stir to obtain red mud slurry. The solid concentration of the red mud slurry is 119.6-136.6 g / L. Determine whether the carbonate content in the sodium carbonate industrial waste liquid is above 20%, and the actual measurement is 21.5%.

[0058] S3. The red mud slurry from S2 is placed in a reactor with a distributed electric field. CO2 gas with a concentration between 39.56% and 55.51% is introduced and the red mud slurry is stirred under high pressure for 45-46 hours to induce carbonization. Afterward, solid-liquid separation is performed to obtain carbonized red mud precipitate and inorganic salt solution. The current density flowing through the cross-section of the red mud slurry is controlled at 12 A / m. 2 Solid-liquid separation involves coagulation and filtration.

[0059] S4. The carbonized red mud precipitated in S3 is screened to obtain coarse carbonized red mud and fine carbonized mud. The coarse carbonized red mud is composed of goethite, hematite and quartz, with a particle size of 0.3-4.75 mm. The fine carbonized mud is mostly composed of diaspore and quartz, with a particle size of no more than 0.3 mm. Therefore, the coarse carbonized red mud is used as a raw material for ironmaking, and the fine carbonized mud is floated to separate aluminum concentrate (Al2O3 58.29%, A / S 5.17) and silicon concentrate (SiO2 98.62%).

[0060] S5. The inorganic salt solution of S3 is passed through CO2 to crystallize baking soda and then recycled as the inorganic salt solution of S2.

[0061] According to the test results, the total iron content was 60.2% and the Na2O content was 0.21% when the raw materials were used for iron smelting.

[0062] Example 2

[0063] A method for the resource utilization of red mud and carbon dioxide, wherein the method for the resource utilization of red mud and carbon dioxide is combined with Figure 1 The following steps are required:

[0064] S1. 10 kg of untreated red mud lumps from a certain area in Guangxi were crushed to obtain red mud particles with a particle size of -4.75 mm, and the particle size of fine mud did not exceed 0.3 mm. After multiple tests, its main components, by mass percentage, were: TFe 9.13-28.35%, Al2O3 5.01-19.86%, SiO2 11.39-29.734%, Na2O 3.73-21.28%, Ca 3.26-19.95%.

[0065] S2. Add sodium carbonate industrial waste liquid containing 2.3% carbonate and water to the red mud particles of S1, and stir to obtain red mud slurry. The solid concentration of the red mud slurry is 2.15-3.06 g / L. Determine whether the carbonate content in the sodium carbonate industrial waste liquid is above 20%. The actual measurement is 8.6%, and sodium carbonate is added to make up the difference.

[0066] S3. The red mud slurry from S2 is placed in a reactor with a distributed electric field. CO2 gas with a concentration between 30% and 39.56% is introduced and the red mud slurry is stirred under high pressure for 3-3.6 hours to induce carbonization. Afterward, solid-liquid separation is performed to obtain carbonized red mud precipitate and inorganic salt solution. The current density flowing through the cross-section of the red mud slurry is controlled at 5 A / m. 2 Solid-liquid separation involves sedimentation and filtration.

[0067] S4. The carbonized red mud precipitated in S3 is screened to obtain coarse carbonized red mud and fine carbonized mud. The coarse carbonized red mud is composed of goethite, hematite and quartz, with a particle size of 0.3-4.75 mm. The fine carbonized mud is mostly composed of diaspore and quartz, with a particle size of no more than 0.3 mm. Therefore, the coarse carbonized red mud is used as a raw material for ironmaking, and the fine carbonized mud is floated to separate aluminum concentrate (Al2O3 56.38%, A / S 5.12) and silicon concentrate (SiO2 98.37%).

[0068] S5. The inorganic salt solution of S3 is passed through CO2 to crystallize baking soda and then recycled as the inorganic salt solution of S2.

[0069] Tests showed that the raw materials used in iron smelting had a total iron content of 59% and a Na2O content of 0.3%.

[0070] Example 3

[0071] A method for the resource utilization of red mud and carbon dioxide, wherein the method for the resource utilization of red mud and carbon dioxide is combined with Figure 1 The following steps are required:

[0072] S1. 10 kg of Shanxi sintered red mud agglomerates were crushed to obtain red mud particles with a particle size of -4.75 mm. After multiple tests, its main components, by mass percentage, were: TFe 5.29-29.36%, Al2O3 3.06-18.97%, SiO2 10.42-29.8%, Na2O 3.75-21.38%, Ca 3.19-23.81%.

[0073] S2. Add sodium carbonate industrial waste liquid containing 56% carbonate and water to the red mud particles of S1, stir to obtain red mud slurry, the solid concentration of red mud slurry is 693g / L; determine whether the carbonate content in sodium carbonate industrial waste liquid is above 20%, the actual measurement is 57.3%.

[0074] S3. The red mud slurry from S2 is placed in a reactor with a distributed electric field. CO2 gas with a concentration between 99% and 99.6% is introduced, and the red mud slurry is stirred by an impeller at a speed of 50-125 rpm for 72 hours to induce carbonization. Afterward, solid-liquid separation is performed to obtain carbonized red mud precipitate and inorganic salt solution. The current density flowing through the cross-section of the red mud slurry is controlled at 350 A / m. 2 Solid-liquid separation is achieved through filtration;

[0075] S4. The carbonized red mud precipitate from S3 is screened to obtain coarse carbonized red mud and fine carbonized mud. The coarse carbonized red mud is composed of quartz, hematite and goethite, with a particle size of 0.3-4.75 mm. The fine carbonized mud is mostly diaspore monohydrate, with a particle size of no more than 0.3 mm, containing 59% Al2O3 and an A / S ratio of 5.2, and is directly used as raw material for leaching alumina.

[0076] S5. The inorganic salt solution of S3 is passed through CO2 to crystallize baking soda and then recycled as the inorganic salt solution of S2.

[0077] Tests have shown that manufactured sand meets the requirements for Class II sand in the "Construction Sand" (GB / T 14684) standard.

[0078] Example 4

[0079] A method for the resource utilization of red mud and carbon dioxide, wherein the method for the resource utilization of red mud and carbon dioxide is combined with Figure 1 The following steps are required:

[0080] S1. 10 kg of red mud lumps from a factory in East China were crushed to obtain red mud particles with a particle size of -4.75 mm. After multiple tests, its main components, by mass percentage, are: TFe 18.25-29.37%, Al2O3 12.19-15.22%, SiO2 8.39-9.75%, Na2O 3.62-19.27%, Ca 3.26-8.97%.

[0081] S2. Add sodium carbonate industrial waste liquid containing 20% ​​carbonate and water to the red mud particles of S1, and stir to obtain red mud slurry. The solid concentration of the red mud slurry is 235-239 g / L. Determine whether the carbonate content in the sodium carbonate industrial waste liquid is above 20%, and the actual measurement is 22.3%.

[0082] S3. Place the red mud slurry from S2 in a reactor with a distributed electric field, introduce CO2 gas with a concentration between 62.5% and 65.5%, and stir the red mud slurry with an impeller at a speed of 50-125 rpm for 35-36 hours to induce carbonization. Afterward, separate the solid and liquid to obtain carbonized red mud precipitate and inorganic salt solution; wherein, the current density flowing through the cross-section of the red mud slurry is controlled to be 8 A / m. 2 Solid-liquid separation includes at least one of sedimentation, coagulation, and filtration;

[0083] S4. The carbonized red mud precipitated in S3 is screened to obtain coarse carbonized red mud and fine carbonized mud. The coarse carbonized red mud is composed of hematite, goethite and quartz, with a particle size of 0.3-4.75 mm. The fine carbonized mud is mostly gibbsite monohydrate, with a particle size of no more than 0.3 mm. Therefore, the coarse carbonized red mud is used as a raw material for ironmaking, and the fine carbonized mud is floated to separate aluminum concentrate (Al2O3 57.71%, A / S 5.06) and silicon concentrate (SiO2 98.13%).

[0084] S5. The inorganic salt solution of S3 is passed through CO2 to crystallize baking soda and then recycled as the inorganic salt solution of S2.

[0085] According to the test results, the total iron content of the raw materials used in iron smelting is 63%, and the Na2O content is 0.26%.

[0086] Comparative Example 1:

[0087] A method for the resource utilization of red mud and carbon dioxide, wherein the method for the resource utilization of red mud and carbon dioxide is combined with Figure 1 The following steps are required:

[0088] S1. 10 kg of red mud from a factory in East China was crushed to obtain red mud particles with a particle size of -4.75 mm. After multiple tests, its main components, by mass percentage, are: TFe 18.25-29.37%, Al2O3 12.19-15.22%, SiO2 8.39-9.75%, Na2O 3.62-19.27%, Ca 3.26-8.97%.

[0089] S2. Add sodium carbonate industrial waste liquid containing 20% ​​carbonate and water to the red mud particles of S1, and stir to obtain red mud slurry. The solid concentration of the red mud slurry is 235-239 g / L. Determine whether the carbonate content in the sodium carbonate industrial waste liquid is above 20%, and the actual measurement is 22.3%.

[0090] S3. Place the red mud slurry from S2 in a reactor with a distributed electric field (without adding an electric field), introduce CO2 gas with a concentration between 62.5% and 65.5%, and stir the red mud slurry with an impeller at a speed of 50-125 rpm for 35-36 hours to induce carbonization. Afterward, separate the solid and liquid to obtain carbonized red mud precipitate and inorganic salt solution; wherein, the current density flowing through the cross-section of the red mud slurry is controlled to be 0 A / m. 2 Solid-liquid separation involves sedimentation and filtration.

[0091] S4. The carbonized red mud precipitated in S3 is screened to obtain coarse carbonized red mud and fine carbonized mud. The coarse carbonized red mud is composed of hematite, goethite and quartz, with a particle size of 0.3-4.75 mm. The fine carbonized mud is mostly gibbsite monohydrate, with a particle size of no more than 0.3 mm. Therefore, the coarse carbonized red mud is used as a raw material for ironmaking, and the fine carbonized mud is floated to separate aluminum concentrate (Al2O3 57%, A / S 5.07) and silicon concentrate (SiO2 98.1%).

[0092] S5. The inorganic salt solution of S3 is passed through CO2 to crystallize baking soda and then recycled as the inorganic salt solution of S2.

[0093] According to the test results, when used as a raw material for iron smelting, the total iron content is 54.5% and the Na2O content is 0.56%.

[0094] Comparing Example 4 and the comparative example, it was found that if the red mud slurry is not treated by an electric field during the CO2 gas-induced carbonization process, although the subsequent treatment method is the same, the total iron grade is lower and the sodium oxide content is more than twice as high. When used as a raw material for ironmaking, the blast furnace will experience symptoms such as frequent blockage of the uniform valve and riser pipe of the charging equipment, large tuyeres, warping of the middle sleeve, white compound overflow from the edges of the middle and large sleeves, and easy thickening of the furnace body. At the same time, the coke ratio of the blast furnace increases, the ironmaking cost increases, and it harms the smooth operation of the blast furnace and the service life of the furnace lining.

[0095] The above-mentioned solution proposes a method for the resource utilization of red mud and carbon dioxide, which can solve the technical defects of existing red mud recycling technologies, such as high cost, low utilization rate, complex preparation process, high operation difficulty, long process and low efficiency, so that red mud can achieve the resource utilization of all components.

[0096] This invention enhances the reaction between traditional red mud slurry and CO2 under the action of an electric field by using an inorganic salt solution containing carbonate ions as an inducer. This transforms the direct carbonization of red mud with CO2 into indirect carbonization, effectively strengthening not only the carbonization depth of red mud but also significantly enhancing its stability and activity. This solves the technical problems of poor stability of red mud particles and the inability of the product to be directly used as raw material for ironmaking or manufactured sand.

[0097] The method for reusing red mud in this invention enables the effective utilization of both the prepared carbonized red mud precipitate and inorganic salt solution. The amount of red mud that can be utilized is higher than that used in the production of concrete, cement, and building bricks. Moreover, the process is not complicated, the operation is easy, the production cost is low, the process is short, and it is conducive to large-scale production.

[0098] In summary, compared with other traditional methods, the method of this invention innovates a method to enhance the carbonization depth in the reuse of red mud. The products and inorganic salt solutions obtained by the indirect carbonization method can be utilized efficiently, with a wide range of applications. The process is simple, and the utilization method is low-cost and highly efficient, which is conducive to large-scale industrial production and promotion.

[0099] The above description represents the preferred embodiments of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for the resource utilization of red mud and carbon dioxide, characterized in that, The method for resource utilization of red mud and carbon dioxide is as follows: S1. Break the red mud lumps to obtain red mud particles; S2. Add an inorganic salt solution containing carbonate to the red mud particles in S1 to prepare a red mud slurry. S3. Place the red mud slurry from S2 into a reactor with a distributed electric field, introduce CO2 gas and stir to induce carbonization reaction, and then separate the solid and liquid to obtain carbonized red mud precipitate and inorganic salt solution. S4. The carbonized red mud precipitated in S3 is screened to obtain coarse carbonized red mud and fine carbonized mud. The coarse carbonized red mud is used as raw material for ironmaking, and the fine carbonized mud is separated by flotation to obtain aluminum concentrate and silicon concentrate. S5. The inorganic salt solution of S3 is passed through CO2 to crystallize baking soda and then recycled as the inorganic salt solution of S2.

2. The method for resource utilization of red mud and carbon dioxide according to claim 1, characterized in that, The particle size of the red mud particles in S1 is -4.75 mm.

3. The method for resource utilization of red mud and carbon dioxide according to claim 1, characterized in that, The carbonate-containing inorganic salt solution in S2 includes at least one of sodium carbonate, lithium carbonate, potassium carbonate, and carbonate-containing industrial waste liquid, and the solid concentration of the red mud slurry is 2.15-693 g / L.

4. The method for resource utilization of red mud and carbon dioxide according to claim 1, characterized in that, The inorganic salt solution containing carbonate in S2 is an industrial waste liquid containing 2.3-56% carbonate, and the solid concentration of the red mud slurry is 2.15-693 g / L.

5. The method for resource utilization of red mud and carbon dioxide according to claim 1, characterized in that, The process parameters for the distributed electric field in reactor S3 need to be set so that the current density flowing through the slurry cross-section is 5-350 A / m. 2 .

6. The method for resource utilization of red mud and carbon dioxide according to claim 1, characterized in that, In S3, CO2 gas is obtained by simultaneously reducing CO2 emissions from CO2-rich gas enriched from flue gas, with CO2 accounting for 30-99.6% of the gas by volume.

7. The method for resource utilization of red mud and carbon dioxide according to claim 1, characterized in that, The stirring in S3 includes mechanical stirring, electromagnetic stirring, or gas stirring.

8. The method for resource utilization of red mud and carbon dioxide according to claim 1, characterized in that, In S3, solid-liquid separation includes at least one of sedimentation, coagulation, and filtration.

9. The method for resource utilization of red mud and carbon dioxide according to claim 1, characterized in that, S4 coarse-grained carbonized red mud consists of hematite, goethite and a small amount of quartz, with a particle size of 0.3-4.75 mm; the fine carbonized mud is mostly composed of boehmite, aluminum hydroxide and quartz, with a particle size not exceeding 0.3 mm.

10. The method for resource utilization of red mud and carbon dioxide according to claim 1, characterized in that, When S4 carbonized red mud is used as a raw material for ironmaking, the total iron content is 55-63% and the Na2O content is <0.3%; when carbonized red mud is used as manufactured sand, it meets the Class II sand requirements of "Construction Sand" (GB / T 14684).

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