Method for preparing pseudo-boehmite with low concentration of co2 and application thereof

Abstract

The application relates to a method for preparing pseudo-boehmite by using low-concentration CO2 and application thereof, and belongs to the technical field of inorganic chemical materials. The method comprises the following steps: preparing a seed slurry; mixing the seed slurry and a sodium metaaluminate solution to prepare a mixed solution; introducing low-concentration CO2-containing gas into the mixed solution and controlling the rising speed of CO2-containing gas bubbles to realize neutralization, gelation and aging. The method can be used for preparing high-purity pseudo-boehmite by using low-concentration CO2, and can realize utilization of industrial waste gas containing CO2.

Description

Technical Field

[0001] The present invention relates to a preparation method of pseudo-boehmite, and more particularly, to a method for preparing pseudo-boehmite using low-concentration CO2. Background Art

[0002] Pseudo-boehmite (AlOOH·nH2O, where 0<n<1) is widely used in petroleum refining, and is commonly used as a binder for fluid catalytic cracking catalysts, and as a precursor for hydrogenation catalysts and reforming catalyst supports (γ-Al2O3). There are many preparation methods for pseudo-boehmite, mainly including aluminum alkoxide hydrolysis method and precipitation method. Among them, the carbonization method, which falls into the category of precipitation method, namely the NaAlO2-CO2 method, uses CO2 as a reaction raw material, which is consistent with the theme of CO2 capture and utilization and meets the requirements of the era of green development.

[0003] During the preparation of pseudo-boehmite by carbonization method, low-concentration CO2 easily causes sodium aluminate to undergo hydrolysis reaction (NaAlO2+2H2O→Al(OH)3+NaOH), thereby generating gibbsite heterogeneous crystals. Therefore, in the prior art, the volume concentration of carbon dioxide for preparing pseudo-boehmite by carbonization method is mostly above 30%:

[0004] CN111592022A discloses a method for preparing pseudo-boehmite by carbonization. Using a sodium aluminate solution with an alumina concentration of 40 to 45 g / L as a raw material, introducing carbon dioxide gas with a volume concentration of 35% to 40%, a qualified pseudo-boehmite product is obtained.

[0005] CN110304644A discloses a method for producing pseudo-boehmite. The method obtains high-purity pseudo-boehmite by reacting a high-purity sodium aluminate solution with carbon dioxide gas with a concentration of 30-50%, and then adopts a hydrothermal high-temperature high-pressure aging treatment for deep sodium removal, thereby obtaining high-purity pseudo-boehmite with high adhesion.

[0006] CN100348493C discloses a production process for preparing pseudo-boehmite. Using a sodium aluminate solution with an alumina concentration of 60-180 g / L as a raw material, high-purity CO2 gas with a volume concentration ≥98.5% as a precipitant, and melamine as a pore-expanding agent, macroporous pseudo-boehmite is prepared.

[0007] CN102838148B discloses a reactor and a method for preparing aluminum hydroxide. The method reacts a sodium aluminate solution with an alumina concentration of 10-60 g / L with CO2 gas with a volume concentration of 50% to 98%, and introduces a self-priming stirrer assembly to improve gas utilization rate, thereby obtaining pseudo-boehmite with concentrated pore size distribution.

[0008] my country's petroleum refining, power, and steel industries emit large amounts of carbon from industrial flue gas. Using this carbonization process to prepare boehmite could achieve a win-win situation of CO2 emission reduction and resource utilization. However, using low-concentration CO2 gas easily leads to impurities, resulting in substandard boehmite quality. Therefore, current technologies for preparing boehmite generally do not use low-concentration CO2 gas (less than 30% by volume). However, industrial flue gas has a low CO2 concentration, mostly below 20% by volume, making it unsuitable for use in preparing high-purity boehmite using existing technologies. Furthermore, there is no current method for preparing high-purity boehmite using low-concentration CO2 gas (referred to as low-concentration CO2). Summary of the Invention

[0009] To overcome the shortcomings of the prior art, the present invention provides a method for preparing pseudoboehmite using low-concentration CO2 gas.

[0010] This invention provides a method for preparing pseudoboehmite, comprising the following steps:

[0011] (1) Under stirring conditions, water, seed crystals and acid are mixed evenly to obtain a seed crystal slurry;

[0012] (2) The seed slurry and sodium aluminate solution are mixed to prepare a sodium aluminate mixture of a certain concentration. The rising speed of CO2 bubbles is controlled by adjusting the flow rate of CO2-containing gas, so that the sodium aluminate mixture and CO2 in the CO2-containing gas are neutralized to form a gel, thus forming a gelled slurry. The CO2-containing gas is a low-concentration CO2-containing gas, and the CO2 concentration therein does not exceed 20% by volume, for example.

[0013] (3) Aging the gelled slurry.

[0014] In step (1), the concentration of the seed crystal slurry, calculated as Al2O3, is preferably 0.2-2% by weight, for example, 0.3-1.5% by weight. The seed crystal is boehmite, and the acid can be an inorganic acid or an organic acid, preferably at least one of hydrochloric acid, nitric acid, sulfuric acid, phosphoric acid, oxalic acid, formic acid, and acetic acid. The acid / aluminum molar ratio (called the acid-aluminum ratio) is 0.05-0.2, preferably 0.05-0.15.

[0015] In one embodiment, in step (1), the seed crystals are mixed with water to form a slurry with a seed crystal concentration of 0.2-2.2% by weight, for example, 0.3-1.6% by weight, based on Al2O3. Then, acid is added according to a molar ratio of acid to seed crystals based on alumina of 0.05-0.2:1, and the mixture is stirred for 20-40 minutes, for example, 30 minutes, to form the seed crystal slurry.

[0016] In step (2), the aluminum content in the seed slurry is 3%-10% by weight of the aluminum content in the sodium aluminate mixture, preferably 5%-8% by weight. The concentration of the sodium aluminate mixture, calculated as Al2O3, is 10-40 g / L, preferably 15-35 g / L.

[0017] In one embodiment, step (2) involves adding the seed slurry and sodium aluminate solution to the reactor and stirring until homogeneous. The weight ratio of the seed crystals (calculated as aluminum) to the sodium aluminate (calculated as aluminum) is 3-10:90-97.

[0018] In step (2), the seed slurry and sodium aluminate solution are mixed in a reactor, and a low-CO2 concentration CO2-containing gas is introduced to carry out the reaction. The reactor includes a gas distributor, through which the gas enters the liquid phase in the form of bubbles from the bottom of the reactor and moves upward to carry out the reaction.

[0019] The gas distributor is mainly used to disperse the gas source into tiny bubbles, thereby ensuring uniform and close contact between the gas and liquid. Existing bubble distributors can be used. In one embodiment, the gas distributor is an annular gas distributor, wherein the gas distribution holes are evenly distributed on an annular distribution plate. The size and number of the gas distribution holes are determined according to the gas inlet volume of the reactor and the required gas flow rate. The gas distribution holes can be circular. In another embodiment, the diameter of the circular gas distribution holes is 2 mm, and they are evenly distributed on the distribution plate.

[0020] CO2-containing gas enters the liquid phase through a gas distributor, forming bubbles known as CO2 bubbles. The rising velocity of these CO2 bubbles is the speed at which they move within the liquid phase. This invention controls the rising velocity of the CO2 bubbles to 10-30 mm / s, ensuring the flow pattern within the reactor is within the pulsed flow range. This prevents excessively high gas velocities from causing CO2 to be carried out of the reaction zone before it can diffuse into the emulsion phase and participate in the reaction. Within this velocity range, sufficient gas residence time and liquid phase gas holdup are guaranteed, enhancing gas-liquid mass transfer. This rising velocity can be determined using a conductivity probe bubble meter or visual inspection.

[0021] The CO2-containing gas has a CO2 volume concentration of 5%-20%, which can be obtained by adjusting with high-concentration CO2 gas, or it can come from industrial flue gas, such as FCC regeneration flue gas, thermal power plant flue gas, steel plant flue gas, boiler flue gas, combustion furnace flue gas, and calcining furnace flue gas. The industrial flue gas is scrubbed industrial flue gas, having been washed in a flue gas scrubbing tower. Typically, the CO2 volume concentration in the industrial flue gas is 5%-20%, and the SOx content is 0-100 mg / m³. 3 NOx content is 0-200 mg / m³ 3 .

[0022] The gelation process has an endpoint pH of 9-11 and a gelation temperature of less than 50°C, for example, 20-40°C.

[0023] The aging conditions described in step (3) are as follows: the aging temperature is controlled at 60-100℃, preferably 80-90℃; the aging time is 30-240 minutes, preferably 60-180 minutes. The time for heating the slurry after gelation in step (2) to the aging temperature is usually no more than 20 minutes.

[0024] The preparation method provided by the present invention may further include step (4):

[0025] (4) The aged slurry is filtered, washed and dried to obtain boehmite dry powder.

[0026] In one embodiment, the washing in step (4) involves washing the filter cake obtained from filtration with deionized water. The washing process ends when the pH value of the washed deionized water reaches 7.0–7.5. The drying conditions are as follows: the drying temperature is 60–120°C, preferably 70–100°C. The drying time can be determined according to the drying method and the required water content after drying. In one embodiment, the drying time is 2–6 hours, preferably 2–4 hours, to obtain boehmite powder.

[0027] This invention promotes rapid nucleation and crystal growth of boehmite by adding activated seed crystals and controlling the appropriate CO2 bubble rise rate. It enables the generation of boehmite even under low CO2 concentration conditions, and the resulting boehmite is free of trihydrate impurities. This solves the problem of producing high-purity boehmite with low-concentration CO2.

[0028] The method for preparing pseudoboehmite provided by this invention can utilize low-concentration CO2 gas to prepare high-purity pseudoboehmite with good colloidal properties, yielding a crystallinity of over 75%, a grain size of 3-4 nm, a pore volume of not less than 0.35 mL / g, and a specific surface area of ​​over 350 m². 2 High-purity boehmite with a concentration of over 1 g / g and a Na₂O content of less than 0.1% by weight, exhibiting good colloidal properties, can be widely used in the preparation of catalysts and adsorbents in the petroleum refining industry. This method for preparing boehmite can also be used for the utilization of CO₂-containing industrial flue gas. Detailed Implementation

[0029] The following embodiments will further illustrate the present invention, but should not be construed as limiting the possible implementations of the present invention. The scope of protection of the present invention is not limited to the following embodiments. In the context of this specification, except for those expressly stated, any matters or issues not mentioned are directly applicable to matters known in the art without any changes. Moreover, any implementation described herein can be freely combined with one or more other implementations described herein, and the resulting technical solutions or technical ideas are considered as part of the original disclosure or original record of the present invention, and should not be regarded as new content not disclosed or anticipated herein, unless those skilled in the art consider such combination to be obviously unreasonable.

[0030] In this application, the gibbsite content, crystallinity, and grain size of the samples were determined by X-ray powder diffraction (XRD) using the RIPP 145-90 and RIPP 146-90 standard methods (see *Petrochemical Analysis Methods* (RIPP Test Methods), edited by Yang Cuiding et al., Science Press, 1990). The formula for calculating grain size is: Where K = 1.075, λ is the wavelength of the Kα1 spectral line of the anodic radiation, β1 is the integral width of the pseudoboehmite 041,130 diffraction peak, and θ is the Bragg diffraction angle of the diffraction peak.

[0031] In this application, the specific surface area and total pore volume of the samples were determined by the BET method using a Micromeritics ASAP 2405N V1.01 automated adsorption analyzer, employing the low-temperature static nitrogen adsorption capacity method. The sample surface area was 1.33 × 10⁻⁶. -2 The sample was degassed under vacuum at 300℃ for 4 hours, using N2 as the adsorption medium, and the adsorption-desorption isotherm was measured at 77.4K. The specific surface area (S) of the sample was calculated according to the BET formula. BET The volume of N2 adsorbed by the sample was measured when the relative pressure p / p0 = 0.98, and then converted into the volume of liquid nitrogen, i.e. the total pore volume.

[0032] In this application, the Na2O content was determined by X-ray fluorescence spectrometry.

[0033] In this application, the determination of the colloidal index (DI) is as follows:

[0034] Weigh 10 grams of boehmite, calcine at 600℃ for 3 hours, cool in a desiccator until room temperature, and weigh to obtain W0 grams. The dry basis weight a0 = W0 / 10. Weigh the boehmite weight m1 = 6 / a0 grams. Place m1 grams of boehmite in a 100 mL PTFE cup, add deionized water to 40 grams, stir evenly with a magnetic rotor, then add 20 mL of 0.19 N dilute nitric acid solution and stir magnetically for 20 minutes. Pour the entire solution into a centrifuge tube and centrifuge at 1900 rpm for 20 minutes. Pour off the upper colloidal solution, place it in a weighed crucible, dry at 80℃, calcine at 600℃ for 3 hours, cool in a desiccator until room temperature, and weigh to obtain m2 grams. The colloidal index DI = (m2 / 6) * 100%.

[0035] Seed crystal: Boehmite, with a relative crystallinity of 85.6%, a grain size of 4nm, and a solid content of 63.89%, produced by Shanxi Aluminum Plant.

[0036] Example 1

[0037] Boehmite seed crystals were added to deionized water and stirred to obtain a slurry of 0.5% by weight (calculated as Al2O3). Hydrochloric acid (36% by weight concentration) was added at an acid-to-aluminum ratio of 0.1, and the mixture was stirred for 30 minutes to obtain a seed crystal slurry. The seed crystal slurry and sodium aluminate solution were added to a reactor to prepare a sodium aluminate mixture with a concentration of 15 g Al2O3 / L (the aluminum content in the seed crystal slurry accounted for 8% by weight of the aluminum content in the sodium aluminate mixture). A CO2 gas (a mixture of CO2 and nitrogen) with a volume concentration of 5% was introduced at room temperature (30℃). The flow rate of the CO2 gas was adjusted so that the rising speed of the bubbles passing through the gas distribution plate was 15 mm / s, and the final pH value was controlled at 10.8. The resulting slurry was aged at 80℃ for 120 minutes. After aging, the mixture was filtered, washed, and the filter cake was dried at 100℃ for 3 hours to obtain boehmite powder Al. Its physicochemical properties are detailed in Table 1.

[0038] Example 2

[0039] A slurry with a concentration of 0.5% by weight (based on Al2O3) was formed by adding boehmite seed crystals to deionized water. Under stirring, nitric acid (68% by weight) was added at an acid-to-aluminum ratio of 0.1 to obtain a seed slurry. The seed slurry and sodium aluminate solution were added to a reactor to prepare a sodium aluminate mixture with a concentration of 20 g Al2O3 / L (the aluminum in the seed slurry was 6% by weight of the aluminum in the sodium aluminate mixture). A CO2-containing gas with a volume concentration of 10% was introduced at room temperature, and the CO2 gas flow rate was adjusted to ensure that the bubble rising speed through the gas distribution plate was 20 mm / s. The final pH value was controlled at 10.5. The resulting slurry was aged at 80℃ for 120 minutes. After aging, the mixture was filtered, washed, and the filter cake was dried at 100℃ for 3 hours to obtain boehmite powder A2. Its physicochemical properties are detailed in Table 1.

[0040] Example 3

[0041] Boehmite seed crystals were added to deionized water to obtain a slurry with a concentration of 0.5 wt% (based on Al2O3). Nitric acid (68 wt%) was added at an acid-to-aluminum ratio of 0.12, and the mixture was stirred to obtain a seed crystal slurry. The seed crystal slurry and sodium aluminate solution were added to a reactor to prepare a sodium aluminate mixture with a concentration of 25 g Al2O3 / L (the aluminum content in the seed crystal slurry accounted for 5 wt% of the aluminum content in the sodium aluminate mixture). Industrial flue gas with a CO2 volume concentration of 15% (this industrial flue gas came from a refining and chemical catalytic cracking unit, and after flue gas scrubbing, the CO2 volume concentration was 15%, and the SOx concentration was 10 mg / m³) was introduced at room temperature. 3 NOx: 20 mg / m³ 3 The industrial flue gas flow rate was adjusted to achieve a bubble velocity of 20 mm / s through the gas distribution plate, and the final pH value was controlled at 10.5. The resulting slurry was aged at 90℃ for 120 minutes. After aging, it was filtered, washed, and the filter cake was dried at 100℃ for 3 hours to obtain pseudoboehmite powder A3. Its physicochemical properties are detailed in Table 1.

[0042] Example 4

[0043] Boehmite seed crystals were added to deionized water to obtain a slurry with a concentration of 1% by weight (based on Al2O3). Hydrochloric acid (36% by weight) was added at an acid-to-aluminum ratio of 0.08, and the mixture was stirred to obtain a seed crystal slurry. The seed crystal slurry and sodium aluminate solution were added to a reactor to prepare a sodium aluminate mixture with a concentration of 35 g Al2O3 / L (the aluminum content in the seed crystal slurry accounted for 5% by weight of the aluminum content in the sodium aluminate mixture). CO2 gas with a volume concentration of 20% was introduced at room temperature, and the CO2 gas flow rate was adjusted to achieve a bubble velocity of 25 mm / s through the gas distribution plate. The final pH value was controlled at 10. The resulting slurry was aged at 90℃ for 120 minutes. After aging, the mixture was filtered, washed, and the filter cake was dried at 100℃ for 3 hours to obtain boehmite powder A4. Its physicochemical properties are detailed in Table 1.

[0044] Example 5

[0045] Boehmite seed crystals were added to deionized water to obtain a slurry with a concentration of 1% by weight (based on Al2O3). Nitric acid (68% by weight) was added at an acid-to-aluminum ratio of 0.12, and the mixture was stirred to obtain a seed crystal slurry. The seed crystal slurry and sodium aluminate solution were added to a reactor to prepare a sodium aluminate mixture with a concentration of 20 g Al2O3 / L (the aluminum content in the seed crystal slurry accounted for 10% by weight of the aluminum content in the sodium aluminate mixture). A CO2-containing gas with a volume concentration of 10% was introduced at room temperature, and the CO2 gas flow rate was adjusted to ensure that the bubble rising speed through the gas distribution plate was 20 mm / s. The final pH value was controlled at 10.5. The resulting slurry was aged at 80℃ for 120 minutes. After aging, the mixture was filtered, washed, and the filter cake was dried at 100℃ for 3 hours to obtain boehmite powder A2. Its physicochemical properties are detailed in Table 1.

[0046] Example 6

[0047] A slurry with a concentration of 0.5% by weight (calculated as Al2O3) was formed by adding boehmite seed crystals to deionized water. Nitric acid (68% by weight) was added at an acid-to-aluminum ratio of 0.2, and the mixture was stirred to obtain the seed crystal slurry. The seed crystal slurry and sodium aluminate solution were added to a reactor to prepare a sodium aluminate solution with a concentration of 20 g Al2O3 / L (the aluminum content in the seed crystal slurry accounted for 6% by weight of the aluminum content in the sodium aluminate mixture). A CO2 gas with a volume concentration of 10% was introduced at room temperature, and the CO2 gas flow rate was adjusted so that the bubble rising speed through the gas distribution plate was 20 mm / s. The final pH value was controlled at 10.5. The resulting slurry was aged at 80℃ for 120 minutes. After aging, the mixture was filtered, washed, and the filter cake was dried at 100℃ for 3 hours to obtain boehmite powder A2. Its physicochemical properties are detailed in Table 1.

[0048] Comparative Example 1

[0049] Boehmite was prepared according to the method in Example 1, except that no seed crystal slurry was added; instead, sodium aluminate and CO2 gas were directly reacted to form a gel. The resulting product was D1. Its physicochemical properties are detailed in Table 1.

[0050] Comparative Example 2

[0051] Boehmite was prepared according to the method in Example 1, except that the CO2 bubble rising speed was 5 mm / s, and the resulting product was D2. Its physicochemical properties are detailed in Table 1.

[0052] Comparative Example 3

[0053] Phytohydrite was prepared according to the method in Example 1, except that no seed crystal slurry was added, the CO2 bubble rising speed was 5 mm / s, and the resulting product was D3. Its physicochemical properties are detailed in Table 1.

[0054] Comparative Example 4

[0055] Boehmite seed crystals were added to deionized water and stirred for 30 min to obtain a seed slurry with a concentration of 0.5 wt% (based on Al2O3). The seed slurry and sodium aluminate solution were added to a reactor to prepare a sodium aluminate mixture with a concentration of 15 g Al2O3 / L (the aluminum content in the seed slurry accounted for 8 wt% of the aluminum content in the sodium aluminate mixture). A CO2-containing gas (a mixture of CO2 and nitrogen) with a volume concentration of 5% was introduced at room temperature. The CO2 gas flow rate was adjusted so that the bubble rising speed through the gas distribution plate was 15 mm / s, and the final pH value was controlled at 10.8. The resulting slurry was aged at 80℃ for 120 minutes. After aging, it was filtered, washed, and the filter cake was dried at 100℃ for 3 hours to obtain boehmite powder D4. Its physicochemical properties are detailed in Table 1.

[0056] Table 1

[0057]

[0058] The data in Table 1 show that the preparation method of the present invention can yield crystallinity of over 75%, crystal size of 3-4 nm, pore volume of not less than 0.35 mL / g, and specific surface area of ​​over 350 m². 2 High-purity boehmite with a concentration of ≥ / g, Na₂O content below 0.1%, and a soluble index (DI) greater than 95%. The obtained boehmite was free of gibbsite impurities. Comparative Examples 1-3 show that without adding seed crystals and controlling the bubble flow rate, gibbsite impurities would form due to the low CO₂ concentration; Comparative Example 4 did not perform activation treatment on the boehmite and therefore failed to eliminate impurities.

[0059] The present application has been described above with reference to specific embodiments; however, these embodiments are merely exemplary and serve only an illustrative purpose. Various substitutions and modifications can be made to the present application based on these embodiments, all of which fall within the protection scope of the present application.

Claims

1. A method for preparing pseudoboehmite, comprising: (1) Mix water, seed crystals and acid evenly, with an acid-to-aluminum ratio of 0.05-0.2, to obtain a seed crystal slurry; the seed crystal is boehmite; the concentration of the seed crystal slurry, calculated as Al2O3, is 0.2-2% by weight%. (2) Prepare a sodium aluminate mixture of seed crystal slurry and sodium aluminate solution to a certain concentration. The aluminum content in the seed crystal slurry is 3%-10% by weight of the aluminum content in the sodium aluminate mixture. The concentration of the sodium aluminate mixture, calculated as Al2O3, is 10-40 g / L. Introduce CO2 gas and control the rising speed of the CO2 gas bubbles to 10-30 mm / s, so that the sodium aluminate mixture and the CO2 in the CO2 gas neutralize and form a gel, thus forming a gelled slurry. The CO2 gas is a low-concentration CO2 gas, and the CO2 concentration in the CO2 gas is 5-20% by volume. (3) Aging the gelled slurry; And optional, (4) The aged slurry is filtered, washed and dried to obtain pseudoboehmite dry powder.

2. The method according to claim 1, characterized in that, The concentration of the seed slurry in step (1) is 0.3~1.5% by weight (calculated as Al2O3), and the acid is at least one of hydrochloric acid, nitric acid, sulfuric acid, phosphoric acid, oxalic acid, formic acid, and acetic acid.

3. The method according to claim 1, characterized in that, In step (1), the acid-aluminum ratio is 0.05-0.

15.

4. The method according to claim 1, characterized in that, In step (2), the aluminum content in the seed slurry is 5%-8% by weight of the aluminum content in the sodium aluminate mixture.

5. The method according to claim 1, characterized in that, In step (2), the concentration of the sodium aluminate mixture is 15-35 g / L, calculated as Al2O3.

6. The method according to claim 1, characterized in that, In step (2), the final pH value of the neutralization gelation is 9-11.

7. The method according to claim 1, characterized in that, In step (2), the neutralization temperature is less than 50°C.

8. The method according to claim 1, characterized in that, In step (2), the seed slurry and sodium aluminate solution are mixed in a reactor, which includes a gas distributor, and the rising speed of the CO2 gas bubbles is controlled at 10-30 mm / s.

9. The method according to claim 1, characterized in that, The aging conditions described in step (3) are as follows: aging temperature is 60-100℃; aging time is 30-240 minutes.

10. The method according to claim 5, characterized in that, In step (2), the volume concentration of CO2 in the CO2-containing gas is 5%-20%; the weight ratio of seed crystals (calculated as aluminum) to sodium aluminate (calculated as aluminum) is 3-10:90-97.

11. The method according to claim 5, characterized in that, In step (2), the CO2-containing gas is industrial flue gas, wherein the CO2 volume concentration is 5%-20% and the SOx content is 0-100 mg / m³. 3 NOx content is 0-200 mg / m³ 3 .

12. The method according to claim 7, characterized in that, In step (2), the neutralization temperature is 20 ~ 40℃.

13. The method according to claim 9, characterized in that, The aging process described in step (3) involves an aging temperature of 80-90°C and an aging time of 60-180 minutes.

14. The application of the method according to any one of claims 1 to 13 in the utilization of CO2-containing waste gas, wherein the pseudoboehmite is used in the preparation of catalysts or adsorbents in the petroleum refining field, and its specific surface area is 350 m². 2 / g or more.

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