Method for preparing flue gas desulfurizer by ball-milling recrystallization method and application of flue gas desulfurizer

Abstract

The invention discloses a method for preparing a flue gas desulfurizer by a ball-milling recrystallization method and application. The flue gas desulfurizer comprises an active component, a precipitator and a surfactant, the active components comprise divalent and trivalent metals; the active component metal exists in a reaction system in the form of precursor salt; the precipitator comprises one or more of sodium hydroxide, potassium hydroxide, sodium carbonate and potassium carbonate; and the surfactant is a water-soluble negative surfactant. The preparation method comprises the following steps: preparing a layered multi-metal hydroxide through a coprecipitation method, carrying out dry and wet two-step ball milling, mixing the layered multi-metal hydroxide with a mother solution separated by the coprecipitation method, adding a proper surfactant, carrying out a dynamic hydrothermal recrystallization reaction, and roasting to obtain the multi-component composite metal oxide desulfurizer. The desulfurization efficiency is enhanced and the cycling stability is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of chemical environmental protection, and in particular, to a method for preparing a flue gas desulfurization agent of a multi-component composite metal oxide by ball milling recrystallization and its application. Background Art

[0002] Environmental protection issues are one of the focuses of attention in today's society. Among numerous air pollutants, SO 2 is the main pollutant with the most serious harm. As a desulfurization technology for commercial applications, flue gas desulfurization can effectively reduce the concentration of SO 2 in the discharged flue gas. Flue gas desulfurization can be mainly divided into wet, dry and semi-dry desulfurization technologies. Among them, the dry desulfurization process has a simple overall process flow and no waste residue generation, becoming the focus of people's research. Dry flue gas desulfurization is to remove organic sulfur in petroleum fractions or SO x in flue gas through physical / chemical adsorption, thereby effectively reducing the emission of gas sulfides. During the entire desulfurization process, the physicochemical properties of the desulfurization agent have a great influence on the desulfurization efficiency.

[0003] At present, for the research on desulfurization agents at home and abroad, metal oxide adsorbents are difficult to reduce and have a low sulfur capacity; due to the unique redox ability of spinels, a series of adsorbents based on spinels loaded with active components such as Ce, V, and Fe have been developed. The preparation process is simple, the desulfurization effect is good, and the process is mature. It is the main type of desulfurization adsorbent for commercial applications at the present stage. However, such adsorbents have a low Mg content, and the bulk phase sulfate is difficult to regenerate and reduce, resulting in unstable activity. The composite metal oxide adsorbent obtained by calcining layered double hydroxides has a relatively high Mg content and has become a research hotspot for desulfurization agents due to its advantages such as high sulfur capacity, large specific surface area, and good cycle stability. However, such adsorbents have problems such as poor abrasion resistance, high production cost, and high reaction temperature. At present, the research direction of this type of adsorbent is how to optimize the preparation process to prepare a composite metal oxide solid desulfurization agent with high strength, high adsorption performance, and low reaction temperature at a lower cost.

[0004] Patent CN 107159093 A discloses a preparation process of a metal oxide flue gas desulfurization adsorbent. By refluxing and treating α-MnO 2 with an alkali solution, a high-temperature resistant MnO 2 flue gas desulfurization agent is obtained. It has good thermal stability and can be used for the removal of sulfur oxides in high-temperature flue gas at 100-750°C; however, compared with composite metal oxides, the overall sulfur capacity of the desulfurization agent is still relatively low (below 10%).

[0005] Patent CN 115253623 A discloses a preparation method of a composite metal oxide type high-temperature flue gas desulfurizer. The active metal is loaded on the surface of the desulfurizer by the impregnation method. When the desulfurizer is treated with flue gas at a concentration of 1500 - 5000 mg / m 3 SO 2 at 650 °C, it shows good regeneration performance, and the desulfurization efficiency is above 95%. However, the dispersion of the active components of the desulfurizer is poor, and the desulfurization reaction temperature is relatively high.

[0006] Patent CN 113713800 A discloses a preparation method of a high-temperature flue gas desulfurizer. A divalent metal ion salt and a water-soluble aluminum salt are subjected to coprecipitation and hydrothermal reaction to obtain a layered double metal hydroxide precursor, and then the catalytic active components are embedded into the precursor through an exchange reaction. Compared with the mechanical mixing method, the two-step reaction can significantly increase the specific surface area of the desulfurizer, and the exchange reaction can also improve the dispersion degree of the active metal compared with the impregnation method. However, the process flow is complex, and the desulfurization and regeneration reaction temperatures must reach 700 °C to show good desulfurization and regeneration performance.

[0007] Patent CN 104209084 A discloses a preparation method of a Claus tail gas SO 2 adsorbent. A transition metal, magnesium, and aluminum nitrate are made into an aqueous solution, and coprecipitated with an alkaline solution to form a hydrotalcite-like powder. Ce, Y, or La is loaded on the surface of the hydrotalcite by the impregnation method, and finally calcined to obtain an adsorbent with a sulfur capacity of more than 10%. The desulfurization rate of the adsorbent for Claus tail gas with a relatively high SO 2 content can reach more than 90%. However, the impregnation method is not conducive to the dispersion of the active metal promoter, which limits the desulfurization activity.

[0008] Patent CN 101829539 A discloses a preparation method of a flower-shaped NiAl composite oxide desulfurizer. Using urea as a precipitating agent, it is hydrothermally heated and stirred at 90 - 100 °C for 24 - 46 h to obtain a NiAl hydrotalcite precursor, and finally calcined at 500 °C for 4 h to obtain a flower-shaped NiAl composite oxide desulfurizer, which shows good SO 2 adsorption performance in the SO 2 adsorption experiment. However, compared with the composite metal oxide desulfurizer, the sulfur capacity is lower at a low temperature of 200 °C.

[0009] Patent CN 102895852 A discloses a clean process preparation method of a catalytic cracking flue gas sulfur transfer agent. A slurry made of oxides, hydroxides, carbonates, or basic carbonates of Mg, Al, and other metal elements is used in CO 2React in a high-pressure autoclave under a certain atmosphere to obtain a sulfur transfer agent for catalytic cracking flue gas. The sulfur transfer agent prepared by this method has good sulfur transfer performance, but compared with the traditional preparation process, the overall desulfurization activity improvement is not high, and the desulfurization reaction temperature is relatively high (732 °C).

[0010] Patent CN 101905117 A discloses a preparation method for the active component of a sulfur transfer agent for catalytic cracking flue gas. The method uses a calcination reduction method to obtain a layered double hydroxide of magnesium and aluminum loaded with Ce or a multi-component layered double hydroxide precursor containing other elements, and then high-temperature calcination is carried out to obtain the sulfur transfer agent for catalytic cracking flue gas. The sulfur transfer agent prepared by this method has a lower reduction temperature and a higher oxidation sulfur absorption capacity. However, the dispersion of the metal promoter is poor, and the reduction reaction temperature is relatively high.

[0011] In view of this, the present application is specifically proposed. Summary of the Invention

[0012] In order to solve the above problems, the object of the present invention is to provide a method and application for preparing a multi-component composite metal oxide flue gas desulfurizer by ball milling recrystallization method. Layered double metal hydroxides are prepared by coprecipitation method, then wet and dry two-step ball milling is carried out, mixed with the mother liquor separated by the coprecipitation method, and a suitable surfactant is added for dynamic hydrothermal recrystallization reaction. Finally, the multi-component composite metal oxide desulfurizer can be obtained by calcination. This method can effectively regulate the mesoscopic structure of the desulfurizer, improve the dispersion of active metals, thereby greatly improving the desulfurization activity, enhancing the desulfurization efficiency, and improving the cycle stability.

[0013] The present invention is realized through the following technical solutions:

[0014] A multi-component composite metal oxide flue gas desulfurizer, comprising an active component, a precipitant and a surfactant;

[0015] The active component includes divalent metals and trivalent metals;

[0016] The divalent metals include one or more of Mg, Ca, Sr, Ba, Zn, Mn, Cu, and the trivalent metals include one or more of Al, Cr, Fe, Ni, La, Ce, Pr;

[0017] The active component metals exist in the reaction system in the form of precursor salts, including one or more of metal sulfates, chlorides, nitrates and acetates;

[0018] The precipitant includes one or more of sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate;

[0019] The surfactant is a water-soluble anionic surfactant, including one or more of sodium dodecyl sulfonate, sodium dodecyl benzene sulfonate, cetyltrimethylammonium bromide, polydiallyldimethylammonium chloride, polyacrylic acid and its salts.

[0020] In the present invention, layered double hydroxides are prepared by the co-precipitation method, and then subjected to two-step dry and wet ball milling, mixed with the mother liquor separated by the co-precipitation method, and a suitable surfactant is added to carry out a dynamic hydrothermal recrystallization reaction. Finally, the multi-component composite metal oxide desulfurizer can be obtained by calcination. This method can effectively regulate the mesoscopic structure of the desulfurizer, enhance the desulfurization efficiency and improve the cycle stability.

[0021] In one embodiment, the molar ratio of the divalent metal to the trivalent metal is 2-5:1; the concentration of the metal salt solution is 1 mol / L (calculated as metal ions).

[0022] In one embodiment, the concentration of sodium hydroxide or potassium hydroxide is 1-2 mol / L, and the concentration of sodium carbonate or potassium carbonate is 0.2-0.6 mol / L.

[0023] In one embodiment, the addition amount of the surfactant is 5-25% of the molar amount of the active metal (calculated as oxide).

[0024] The present invention also provides a preparation method of a multi-component composite metal oxide flue gas desulfurizer, comprising the following steps:

[0025] S1, preparing layered double hydroxides by the co-precipitation method

[0026] S11, mixing the metal active component precursor salt and water at room temperature to obtain a first slurry;

[0027] S12, mixing the precipitant and water to obtain a second slurry;

[0028] S13, at a certain temperature, mixing the first slurry and the second slurry at a certain dropping rate to ensure that the pH value of the reaction system is maintained within a certain range. After mixing, aging treatment is carried out at a certain temperature for a certain time, and the reaction mother liquor and the precipitate are filtered; the precipitate is washed to neutral, dried and ground into powder to obtain layered double hydroxides;

[0029] S2, two-step dry and wet ball milling: uniformly mixing the layered double hydroxides obtained by co-precipitation with zirconia balls, and putting them into a zirconia ball mill tank for dry ball milling; adding a certain amount of deionized water to the above ball mill tank and continuing to ball mill to finally obtain a ball mill slurry;

[0030] S3, Recrystallization: Mix the reaction mother liquor in step S13 and the ball-milled slurry in step S2 in a certain proportion, add an appropriate amount of surfactant and stir evenly. Place the above reaction solution in a polytetrafluoroethylene high-pressure reaction kettle, carry out dynamic crystallization reaction at a certain temperature for a certain time to obtain a reaction precipitate;

[0031] S4, Calcination: After centrifugally washing, drying, grinding into powder and calcining the above reaction precipitate, a multi-component composite metal oxide desulfurizer is obtained;

[0032] S5, Granulation: Granulate the desulfurizer powder on a tabletting machine, and after crushing, desulfurizer particles with a certain particle size are obtained.

[0033] In one embodiment, in step S13, the temperature of the mixing reaction of the first slurry and the second slurry is 40 - 60 °C.

[0034] In one embodiment, in step S13, the dropping rate of the first slurry is 20 - 50 ml / h, and the dropping rate of the second slurry is adjusted to maintain the pH of the reaction system at 8 - 10.

[0035] In one embodiment, in step S13, the temperature of the aging treatment is 70 - 100 °C, and the aging time is 12 - 24 h.

[0036] In one embodiment, in steps S13 and S4, the drying temperature is 70 - 90 °C, and the time is 8 - 16 h.

[0037] In one embodiment, in step S2, the mass ratio of the layered multi-metal hydroxide to the zirconia balls in the dry ball-milling process is 60:1, and the ball-milling time is 1 - 6 h.

[0038] In one embodiment, in step S2, the amount of deionized water added in the wet ball-milling process is 25 - 100 wt% of the amount of the layered multi-metal hydroxide.

[0039] In one embodiment, in step S3, the ball-milled slurry and the reaction mother liquor are mixed in a mass ratio of 1:10 - 30, the temperature of the dynamic recrystallization hydrothermal reaction is 70 - 100 °C, the crystallization time is 8 - 16 h, and the oven rotation speed is 50 - 100 rpm.

[0040] In one embodiment, in step S4, the centrifugal washing is to wash with deionized water until neutral, and the last wash is with ethanol.

[0041] In one embodiment, in step S4, the calcination temperature is 400 - 700 °C, the calcination time is 5 - 12 h, and the heating rate is 2 °C / min.

[0042] In one embodiment, in step S5, the particle size of the powder is 10 - 40 mesh.

[0043] The present invention also provides the application of the multi-component composite metal oxide flue gas desulfurizer or the multi-component composite metal oxide desulfurizer prepared by the ball milling recrystallization method in flue gas desulfurization.

[0044] In the present invention, the sulfur-containing flue gas is preferably the flue gas discharged after the Claus sulfur recovery unit of a refinery or a purification plant; the volume fraction of SO 2 in the sulfur-containing flue gas is 0.1-2%, and the volume fraction of O 2 is 2-8%; the adsorption reaction temperature is 400-600 °C.

[0045] In the present invention, the desulfurization reaction process is carried out in a fixed bed reactor. The flue gas flows through the solid bed layer, and SO 2 in the flue gas is converted into metal sulfate and fixed on the desulfurizer through catalytic oxidation. Then, under the action of the reducing gas, the sulfur in the metal sulfate on the desulfurizer is reduced to elemental sulfur, SO 2 and H 2 S, and at the same time, the desulfurizer is regenerated. The reduced gas is returned to the sulfur recovery unit to further recover the sulfur therein.

[0046] The reducing and regenerating gas is one of 10% H 2 / N 2 , 10% H 2 S / N 2 , 10% CH 4 / N 2 , 10% CO / N 2 , and preferably 10% H 2 / N 2 .

[0047] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0048] 1. The multi-component composite metal oxide flue gas desulfurizer provided by the embodiment of the present invention can exert the role of the active metal to the maximum by using the synergistic effect of multiple metals, and has high desulfurization efficiency and cycle stability;

[0049] 2. The method for preparing a multi-component composite metal oxide flue gas desulfurizer by the ball milling recrystallization method provided by the embodiment of the present invention prepares layered multi-metal hydroxides by the coprecipitation method, then performs wet and dry two-step ball milling, mixes with the mother liquor separated by the coprecipitation method, and adds a suitable surfactant to carry out a dynamic hydrothermal recrystallization reaction, and finally calcines to obtain the multi-component composite metal oxide desulfurizer, which can effectively regulate the mesoscopic structure of the desulfurizer, improve the dispersion degree of the active metal, thereby greatly improving the desulfurization activity, enhancing the desulfurization efficiency, and improving the cycle stability. Detailed implementation mode

[0050] To make the objectives, technical solutions and advantages of the present invention more clear and understandable, the present invention will be further described in detail below in conjunction with embodiments. The illustrative embodiments and descriptions of the present invention are only used to explain the present invention and are not intended to limit the present invention.

[0051] In the following description, a large number of specific details are set forth in order to provide a thorough understanding of the present invention. However, it will be apparent to those of ordinary skill in the art that: These specific details do not have to be employed to practice the present invention. In other embodiments, well-known structures, circuits, materials, or methods have not been specifically described in order to avoid obscuring the present invention.

[0052] Throughout the specification, references to "one embodiment", "an embodiment", "an example", or "an example" mean that a particular feature, structure, or characteristic described in connection with the embodiment or example is included in at least one embodiment of the present invention. Thus, the phrases "one embodiment", "an embodiment", "an example", or "an example" appearing throughout the specification do not necessarily all refer to the same embodiment or example. Additionally, the specific features, structures, or characteristics may be combined in any suitable combination and / or sub-combination in one or more embodiments or examples. The term "and / or" used herein includes any and all combinations of one or more of the associated listed items.

[0053] In the description of the present invention, the orientation or positional relationships indicated by the terms "front", "rear", "left", "right", "upper", "lower", "vertical", "horizontal", "high", "low", "inner", "outer", etc. are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as limiting the protection scope of the present invention.

[0054] Embodiment 1

[0055] A method for preparing a multi-component composite metal oxide flue gas desulfurizer by ball milling recrystallization provided by an embodiment of the present invention specifically includes the following steps:

[0056] (1) Preparation of layered double hydroxides

[0057] Prepare 200 ml of a mixed solution of magnesium nitrate, zinc nitrate, aluminum nitrate, and cerium nitrate, denoted as mixed solution I; wherein, the concentration of magnesium nitrate is 0.7425 mol / L, the concentration of zinc nitrate is 0.0075 mol / L, the concentration of aluminum nitrate is 0.21 mol / L, and the concentration of cerium nitrate is 0.04 mol / L.

[0058] Prepare 200 ml of sodium hydroxide and sodium carbonate solution, denoted as mixture II; among them, the concentration of the sodium hydroxide solution is 2 mol / L, and the concentration of the sodium carbonate solution is 0.5 mol / L.

[0059] Add mixture I and II to another beaker at a certain dropping rate and stir rapidly at the same time. Among them, the dropping rate of mixture I is 40 ml / h. During the dropping process, control the dropping rate of mixture II to maintain the pH value of the reaction system within the range of 9 - 10, control the reaction temperature at 60 °C, and obtain mixture III after the dropping is completed.

[0060] Age mixture III at 90 °C for 24 h, then centrifuge to obtain a precipitate and mother liquor; wash the precipitate with deionized water until neutral, finally wash it once with ethanol, and then dry it in an oven at 85 °C for 12 h to obtain layered double hydroxides.

[0061] (2) Two-step dry and wet ball milling

[0062] Put 3 g of the layered double hydroxides prepared above into a 100 ml ball milling jar, then add 180 g of zirconia balls with a ratio of Φ3mm:Φ6mm:Φ10mm = 20:40:100 (the beads account for about 1 / 4 of the volume of the ball milling jar), and dry ball mill in a planetary ball mill at a ball milling speed of 100 rpm (rotation of the ball milling jar) for 2 h. After the dry ball milling is completed, add 1 g of deionized water and continue wet ball milling at a ball milling speed of 100 rpm (rotation of the ball milling jar) for 2 h. After the ball milling is completed, separate the zirconia balls and liquid in the ball milling jar, filter and wash, and place them in an oven at 85 °C for 12 h to obtain a ball milled layered double hydroxides sample.

[0063] (3) Recrystallization

[0064] Take 2.5 g of the layered double hydroxides obtained from the two-step dry and wet ball milling in step (2) and put them into a 100 ml beaker, add 25 g of the mother liquor separated during the preparation of the layered double hydroxides and 0.25 g of sodium dodecyl sulfonate, stir strongly at room temperature for 1 h, then transfer to a 100 ml polytetrafluoroethylene autoclave, crystallize at 100 °C for 8 h, and the oven rotation speed is 60 rpm. After the recrystallization is completed, centrifuge and wash with deionized water until neutral, finally wash once with ethanol, dry the obtained solid in an oven at 85 °C for 12 h, and then grind it into powder.

[0065] (4) Preparation of multi-component composite metal oxide desulfurizer

[0066] Transfer the layered double hydroxide powder obtained by recrystallization in step (3) into a muffle furnace, and calcine it in an air atmosphere at 500 °C for 8 h to obtain a composite metal oxide desulfurizer R1, where the heating rate is 2 °C / min. The calcined solid powder is pressed on a powder press. After pressing and crushing it into 20-40 mesh particles, it can be used for flue gas desulfurization reaction.

[0067] Example 2

[0068] A method for preparing a multi-component composite metal oxide desulfurizer by ball milling and recrystallization provided by an embodiment of the present invention specifically includes the following steps:

[0069] (1) Preparation of layered double hydroxide

[0070] Prepare 200 ml of a mixed solution of magnesium nitrate, zinc nitrate, aluminum nitrate, and cerium nitrate, denoted as mixed solution I; among them, the concentration of magnesium nitrate is 0.7425 mol / L, the concentration of zinc nitrate is 0.0075 mol / L, the concentration of aluminum nitrate is 0.21 mol / L, and the concentration of cerium nitrate is 0.04 mol / L.

[0071] Prepare 200 ml of a sodium hydroxide and sodium carbonate solution, denoted as mixed solution II; among them, the concentration of the sodium hydroxide solution is 2 mol / L, and the concentration of the sodium carbonate solution is 0.5 mol / L.

[0072] Add mixed solution I and II to another beaker simultaneously at a certain dropping rate and stir rapidly, where the dropping rate of mixed solution I is 40 ml / h. During the dropping process, control the dropping rate of mixed solution II to maintain the pH value of the reaction system within the range of 9-10, control the reaction temperature at 60 °C, and obtain mixed solution III after the dropping is completed.

[0073] Age the mixed solution III at 90 °C for 24 h, then centrifuge to separate the precipitate and the mother liquor; wash the precipitate with deionized water until neutral, finally wash it once with ethanol, and then dry it in an oven at 85 °C for 12 h to obtain layered double hydroxide.

[0074] (2) Two-step dry and wet ball milling

[0075] Put 3 g of the prepared layered double hydroxide into a 100 ml ball milling jar, then add 180 g of zirconia balls with a ratio of Φ3 mm:Φ6 mm:Φ10 mm = 20:40:100 (the beads account for about 1 / 4 of the volume of the ball milling jar), and dry ball mill for 2 h at a ball milling speed of 300 rpm (rotation of the ball milling jar). After the dry ball milling is completed, add 1 g of deionized water and continue wet ball milling for 2 h at a ball milling speed of 300 rpm (rotation of the ball milling jar). After the ball milling is completed, separate the zirconia balls and liquid in the ball milling jar, filter and wash, and place them in an oven at 85 °C for drying for 12 h to obtain a ball milled layered double hydroxide sample.

[0076] (3) Recrystallization

[0077] Take 2.5 g of the layered double hydroxide obtained from the two-step dry and wet ball milling in step (2) and put it into a 100 ml beaker. Add 25 g of the mother liquor separated during the preparation of the layered double hydroxide and 0.25 g of sodium dodecyl sulfonate, and stir strongly at room temperature for 1 h. Then transfer it to a 100 ml polytetrafluoroethylene autoclave and crystallize at 100 °C for 8 h with an oven rotation speed of 60 rpm. After the recrystallization is completed, centrifuge and wash with deionized water until neutral, and finally wash once with ethanol. The obtained solid is dried in an oven at 85 °C for 12 h and then ground into powder.

[0078] (4) Preparation of the multi-component composite metal oxide desulfurizer

[0079] Transfer the layered double hydroxide powder prepared by recrystallization in step (3) to a muffle furnace and calcine it in an air atmosphere at 500 °C for 8 h to obtain the composite metal oxide desulfurizer R2, where the heating rate is 2 °C / min. The calcined solid powder is pressed on a powder tablet press. After pressing and crushing into 20 - 40 mesh particles, it can be used for the flue gas desulfurization reaction.

[0080] Example 3

[0081] A method for preparing a multi-component composite metal oxide desulfurizer by ball milling and recrystallization provided by an embodiment of the present invention specifically includes the following steps:

[0082] (1) Preparation of layered double hydroxide

[0083] Prepare 200 ml of a mixed solution of magnesium nitrate, zinc nitrate, aluminum nitrate, and cerium nitrate, denoted as mixed solution Ⅰ; among them, the concentration of magnesium nitrate is 0.7425 mol / L, the concentration of zinc nitrate is 0.0075 mol / L, the concentration of aluminum nitrate is 0.21 mol / L, and the concentration of cerium nitrate is 0.04 mol / L.

[0084] Prepare 200 ml of sodium hydroxide and sodium carbonate solution, denoted as mixture II; among them, the concentration of the sodium hydroxide solution is 2 mol / L, and the concentration of the sodium carbonate solution is 0.5 mol / L.

[0085] Add mixture I and II to another beaker simultaneously at a certain dropping rate and stir rapidly. Among them, the dropping rate of mixture I is 40 ml / h. During the dropping process, control the dropping rate of mixture II to maintain the pH value of the reaction system within the range of 9 - 10, and control the reaction temperature at 60 °C. After the dropping is completed, obtain mixture III.

[0086] Age mixture III at 90 °C for 24 h, then centrifuge to obtain a precipitate and a mother liquor. Wash the precipitate with deionized water until neutral, and finally wash it once with ethanol, and then dry it in an 85 °C oven for 12 h to obtain layered double hydroxides.

[0087] (2) Two-step dry and wet ball milling

[0088] Put 3 g of the layered double hydroxides prepared above into a 100 ml ball milling jar, and then add 180 g of zirconia balls with a ratio of Φ3 mm:Φ6 mm:Φ10 mm = 20:40:100 (the beads approximately account for 1 / 4 of the volume of the ball milling jar). Dry ball mill in a planetary ball mill at a ball milling speed of 100 rpm (counting the rotation of the ball milling jar) for 2 h. After the dry ball milling is completed, add 1 g of deionized water and continue wet ball milling at a ball milling speed of 100 rpm (counting the rotation of the ball milling jar) for 4 h. After the ball milling is completed, separate the zirconia balls and liquid in the ball milling jar, filter and wash, and place them in an 85 °C oven to dry for 12 h to obtain a ball milled layered double hydroxides sample.

[0089] (3) Recrystallization

[0090] Take 2.5 g of the layered double hydroxides obtained from the two-step dry and wet ball milling in step (2) and put it into a 100 ml beaker. Add 25 g of the mother liquor separated during the preparation of the layered double hydroxides and 0.25 g of sodium dodecyl sulfonate, and stir strongly at room temperature for 1 h, then transfer it to a 100 ml polytetrafluoroethylene high-pressure reaction kettle, crystallize at 100 °C for 8 h, and the oven rotation speed is 60 rpm. After the recrystallization is completed, centrifuge and wash with deionized water until neutral, and finally wash it once with ethanol. The obtained solid is dried in an 85 °C oven for 12 h, and then ground into powder.

[0091] (4) Preparation of multi-component composite metal oxide desulfurizer

[0092] Transfer the layered double hydroxide powder obtained by recrystallization in step (3) into a muffle furnace, and calcine it in an air atmosphere at 500 °C for 8 h to obtain the composite metal oxide desulfurizer R3, where the heating rate is 2 °C / min. After calcination, the solid powder is pressed into tablets on a powder press. After pressing and crushing into 20-40 mesh particles, it can be used for flue gas desulfurization reaction.

[0093] Example 4

[0094] A method for preparing a multi-component composite metal oxide desulfurizer by ball milling and recrystallization provided by an embodiment of the present invention specifically includes the following steps:

[0095] (1) Preparation of layered double hydroxide

[0096] Prepare a 200 ml mixed solution of magnesium nitrate, zinc nitrate, aluminum nitrate, and cerium nitrate, denoted as mixed solution I; among them, the concentration of magnesium nitrate is 0.7425 mol / L, the concentration of zinc nitrate is 0.0075 mol / L, the concentration of aluminum nitrate is 0.21 mol / L, and the concentration of cerium nitrate is 0.04 mol / L.

[0097] Prepare a 200 ml solution of sodium hydroxide and sodium carbonate, denoted as mixed solution II; among them, the concentration of the sodium hydroxide solution is 2 mol / L, and the concentration of the sodium carbonate solution is 0.5 mol / L.

[0098] Add mixed solution I and II to another beaker at a certain dropping rate and stir quickly. Among them, the dropping rate of mixed solution I is 40 ml / h. During the dropping process, the dropping rate of mixed solution II is controlled to maintain the pH value of the reaction system within the range of 9-10, and the reaction temperature is controlled at 60 °C. After dropping, mixed solution III is obtained.

[0099] Age mixed solution III at 90 °C for 24 h, then centrifuge to separate the precipitate and the mother liquor. The precipitate is washed with deionized water until neutral, finally washed once with ethanol, and then dried in an oven at 85 °C for 12 h to obtain layered double hydroxide.

[0100] (2) Two-step dry and wet ball milling

[0101] Put 3 g of the prepared layered double hydroxide into a 100-ml ball mill jar, then add 180 g of zirconia balls with a ratio of Φ3 mm:Φ6 mm:Φ10 mm = 20:40:100 (the beads account for about 1 / 4 of the volume of the ball mill jar), and dry ball mill for 4 h at a ball milling speed of 100 rpm (rotation of the ball mill jar) in a planetary ball mill. After the dry ball milling is completed, add 1 g of deionized water and continue wet ball milling for 2 h at a ball milling speed of 100 rpm (rotation of the ball mill jar). After the ball milling is completed, separate the zirconia balls and the liquid in the ball mill jar, filter and wash them, and place them in an oven at 85 °C for drying for 12 h to obtain a ball-milled layered double hydroxide sample.

[0102] (3) Recrystallization

[0103] Put 2.5 g of the layered double hydroxide obtained by two-step dry and wet ball milling in step (2) into a 100-ml beaker, add 25 g of the mother liquor separated during the preparation of the layered double hydroxide and 0.25 g of sodium dodecyl sulfonate, stir strongly at room temperature for 1 h, then transfer it to a 100-ml polytetrafluoroethylene autoclave, crystallize at 100 °C for 8 h, and the oven rotation speed is 60 rpm. After the recrystallization is completed, centrifuge and wash with deionized water until neutral, and finally wash once with ethanol. The obtained solid is dried in an oven at 85 °C for 12 h and then ground into powder.

[0104] (4) Preparation of the multi-component composite metal oxide desulfurizer

[0105] Transfer the layered double hydroxide powder prepared by recrystallization in step (3) to a muffle furnace, and calcine it in an air atmosphere at 500 °C for 8 h to obtain a composite metal oxide desulfurizer R4, where the heating rate is 2 °C / min. The calcined solid powder is pressed on a powder tablet press, and after being pressed and crushed into 20-40 mesh particles, it can be used for the flue gas desulfurization reaction.

[0106] Example 5

[0107] A method for preparing a multi-component composite metal oxide desulfurizer by ball milling and recrystallization provided by an embodiment of the present invention specifically includes the following steps:

[0108] (1) Preparation of layered double hydroxide

[0109] Prepare 200 ml of a mixed solution of magnesium nitrate, zinc nitrate, aluminum nitrate, and cerium nitrate, denoted as mixed solution I; among them, the concentration of magnesium nitrate is 0.7425 mol / L, the concentration of zinc nitrate is 0.0075 mol / L, the concentration of aluminum nitrate is 0.21 mol / L, and the concentration of cerium nitrate is 0.04 mol / L.

[0110] Prepare 200 ml of sodium hydroxide and sodium carbonate solution, denoted as mixture II; among them, the concentration of the sodium hydroxide solution is 2 mol / L, and the concentration of the sodium carbonate solution is 0.5 mol / L.

[0111] Add mixture I and II to another beaker simultaneously at a certain dropping rate and stir rapidly. Among them, the dropping rate of mixture I is 40 ml / h. During the dropping process, control the dropping rate of mixture II to maintain the pH value of the reaction system within the range of 9 - 10, control the reaction temperature at 60 °C, and obtain mixture III after the dropping is completed.

[0112] Age mixture III at 90 °C for 24 h, then centrifuge to obtain a precipitate and mother liquor. Wash the precipitate with deionized water until it is neutral, and finally wash it once with ethanol, and then dry it in an oven at 85 °C for 12 h to obtain layered double hydroxides.

[0113] (2) Two-step dry and wet ball milling

[0114] Put 3 g of the layered double hydroxides prepared above into a 100 ml ball milling jar, then add 180 g of zirconia balls with a ratio of Φ3 mm:Φ6 mm:Φ10 mm = 20:40:100 (the beads approximately account for 1 / 4 of the volume of the ball milling jar), and dry ball mill in a planetary ball mill at a ball milling speed of 100 rpm (counting the rotation of the ball milling jar) for 2 h. After the dry ball milling is completed, add 3 g of deionized water and continue wet ball milling at a ball milling speed of 100 rpm (counting the rotation of the ball milling jar) for 2 h. After the ball milling is completed, separate the zirconia balls and liquid in the ball milling jar, filter and wash, and place them in an oven at 85 °C for 12 h to obtain a ball milled layered double hydroxides sample.

[0115] (3) Recrystallization

[0116] Take 2.5 g of the layered double hydroxides obtained from the two-step dry and wet ball milling in step (2) and put it into a 100 ml beaker, and add 25 g of the mother liquor separated during the preparation of the layered double hydroxides and 0.25 g of sodium dodecyl sulfonate, stir strongly at room temperature for 1 h, then transfer it to a 100 ml polytetrafluoroethylene high-pressure reaction kettle, crystallize at 100 °C for 8 h, and the oven rotation speed is 60 rpm. After the recrystallization is completed, centrifuge and wash with deionized water until it is neutral, and finally wash it once with ethanol. The obtained solid is dried in an oven at 85 °C for 12 h, and then ground into powder.

[0117] (4) Preparation of multi-component composite metal oxide desulfurizer

[0118] Transfer the layered double hydroxide powder obtained by recrystallization in step (3) into a muffle furnace, and calcine it in an air atmosphere at 500 °C for 8 h to obtain a composite metal oxide desulfurizer R5, where the heating rate is 2 °C / min. The calcined solid powder is pressed on a powder tablet press. After pressing and crushing it into 20-40 mesh particles, it can be used for flue gas desulfurization reaction.

[0119] Example 6

[0120] A method for preparing a multi-component composite metal oxide desulfurizer by ball milling and recrystallization provided by an embodiment of the present invention specifically includes the following steps:

[0121] (1) Preparation of layered double hydroxide

[0122] Prepare 200 ml of a mixed solution of magnesium nitrate, zinc nitrate, aluminum nitrate, and cerium nitrate, denoted as mixed solution I; among them, the concentration of magnesium nitrate is 0.7425 mol / L, the concentration of zinc nitrate is 0.0075 mol / L, the concentration of aluminum nitrate is 0.21 mol / L, and the concentration of cerium nitrate is 0.04 mol / L.

[0123] Prepare 200 ml of a sodium hydroxide and sodium carbonate solution, denoted as mixed solution II; among them, the concentration of the sodium hydroxide solution is 2 mol / L, and the concentration of the sodium carbonate solution is 0.5 mol / L.

[0124] Add mixed solutions I and II to another beaker simultaneously at a certain dropping rate and stir rapidly. Among them, the dropping rate of mixed solution I is 40 ml / h. During the dropping process, control the dropping rate of mixed solution II to maintain the pH value of the reaction system within the range of 9-10, and control the reaction temperature at 60 °C. After the dropping is completed, obtain mixed solution III.

[0125] Age mixed solution III at 90 °C for 24 h, and then centrifuge to separate the precipitate and the mother liquor. Wash the precipitate with deionized water until it is neutral, and finally wash it once with ethanol, and then dry it in an oven at 85 °C for 12 h to obtain layered double hydroxide.

[0126] (2) Two-step dry and wet ball milling

[0127] Put 3 g of the prepared layered double hydroxide into a 100 ml ball milling jar, then add 180 g of zirconia balls with a ratio of Φ3 mm: Φ6 mm: Φ10 mm = 20:40:100 (the balls approximately account for 1 / 4 of the volume of the ball milling jar), and dry ball mill in a planetary ball mill at a ball milling speed of 100 rpm (rotation of the ball milling jar) for 2 h. After the dry ball milling is completed, add 1 g of deionized water and continue wet ball milling at a ball milling speed of 100 rpm (rotation of the ball milling jar) for 2 h. After the ball milling is completed, separate the zirconia balls and liquid in the ball milling jar, filter and wash, and place them in an oven at 85 °C for drying for 12 h to obtain a ball milled layered double hydroxide sample.

[0128] (3) Recrystallization

[0129] Take 2.5 g of the layered double hydroxide obtained from the two-step dry and wet ball milling in step (2) and put it into a 100 ml beaker. Add 25 g of the mother liquor separated during the preparation of the layered double hydroxide and 0.25 g of polyacrylic acid, and stir strongly at room temperature for 1 h. Then transfer it to a 100 ml polytetrafluoroethylene autoclave and crystallize at 100 °C for 8 h with an oven rotation speed of 60 rpm. After the recrystallization is completed, perform centrifugal separation, wash with deionized water until neutral, and finally wash once with ethanol. The obtained solid is dried in an oven at 85 °C for 12 h and then ground into powder.

[0130] (4) Preparation of the multi-component composite metal oxide desulfurizer

[0131] Transfer the layered double hydroxide powder obtained by recrystallization in step (3) to a muffle furnace and calcine it in an air atmosphere at 500 °C for 8 h to obtain the composite metal oxide desulfurizer R7, where the heating rate is 2 °C / min. The calcined solid powder is pressed on a powder press. After pressing and crushing into 20 - 40 mesh particles, it can be used for the flue gas desulfurization reaction.

[0132] Example 7

[0133] A method for preparing a multi-component composite metal oxide desulfurizer by ball milling and recrystallization provided by an embodiment of the present invention specifically includes the following steps:

[0134] (1) Preparation of the layered double hydroxide

[0135] Prepare a 200 ml mixed solution of magnesium nitrate, zinc nitrate, aluminum nitrate, and cerium nitrate, denoted as mixed solution Ⅰ; among them, the concentration of magnesium nitrate is 0.7425 mol / L, the concentration of zinc nitrate is 0.0075 mol / L, the concentration of aluminum nitrate is 0.21 mol / L, and the concentration of cerium nitrate is 0.04 mol / L.

[0136] Prepare 200 ml of sodium hydroxide and sodium carbonate solution, denoted as mixture II; among them, the concentration of the sodium hydroxide solution is 2 mol / L, and the concentration of the sodium carbonate solution is 0.5 mol / L.

[0137] Add mixture I and II to another beaker simultaneously at a certain dropping rate and stir rapidly. Among them, the dropping rate of mixture I is 40 ml / h. During the dropping process, control the dropping rate of mixture II to maintain the pH value of the reaction system within the range of 9 - 10, control the reaction temperature at 60 °C, and obtain mixture III after the dropping is completed.

[0138] Age mixture III at 90 °C for 24 h, then centrifuge to obtain a precipitate and a mother liquor. Wash the precipitate with deionized water until it is neutral, finally wash it once with ethanol, and then dry it in an oven at 85 °C for 12 h to obtain layered double hydroxides.

[0139] (2) Two-step dry and wet ball milling

[0140] Put 3 g of the layered double hydroxides prepared above into a 100 ml ball milling jar, then add 180 g of zirconia balls with a ratio of Φ3mm:Φ6mm:Φ10mm = 20:40:100 (the beads account for about 1 / 4 of the volume of the ball milling jar), and dry ball mill in a planetary ball mill at a ball milling speed of 100 rpm (counting the rotation of the ball milling jar) for 2 h. After the dry ball milling is completed, add 1 g of deionized water and continue wet ball milling at a ball milling speed of 100 rpm (counting the rotation of the ball milling jar) for 2 h. After the ball milling is completed, separate the zirconia balls and liquid in the ball milling jar, filter and wash, and place them in an oven at 85 °C for 12 h to obtain a ball milled layered double hydroxides sample.

[0141] (3) Recrystallization

[0142] Take 2.5 g of the layered double hydroxides obtained from the two-step dry and wet ball milling in step (2) and put it into a 100 ml beaker, add 25 g of the mother liquor separated during the preparation of the layered double hydroxides, stir strongly at room temperature for 1 h, then transfer it to a 100 ml polytetrafluoroethylene high-pressure reaction kettle, crystallize at 100 °C for 8 h, and the oven rotation speed is 60 rpm. After the recrystallization is completed, centrifuge and wash with deionized water until it is neutral, finally wash it once with ethanol, dry the obtained solid in an oven at 85 °C for 12 h, and then grind it into powder.

[0143] (4) Preparation of multi-component composite metal oxide desulfurizer

[0144] Transfer the layered double hydroxide powder obtained by recrystallization in step (3) into a muffle furnace, and calcine it at 500 °C for 8 h in an air atmosphere to obtain the composite metal oxide desulfurizer R8, where the heating rate is 2 °C / min. The calcined solid powder is pressed on a powder press. After pressing and crushing it into 20-40 mesh particles, it can be used for flue gas desulfurization reaction.

[0145] Comparative Example 1

[0146] A preparation method of a multi-component composite metal oxide desulfurizer provided in this comparative example specifically includes the following steps:

[0147] (1) Preparation of layered double hydroxide

[0148] Prepare a 200 ml mixed solution of magnesium nitrate, zinc nitrate, aluminum nitrate, and cerium nitrate, denoted as mixed solution I; among them, the concentration of magnesium nitrate is 0.7425 mol / L, the concentration of zinc nitrate is 0.0075 mol / L, the concentration of aluminum nitrate is 0.21 mol / L, and the concentration of cerium nitrate is 0.04 mol / L.

[0149] Prepare a 200 ml solution of sodium hydroxide, sodium carbonate, and sodium dodecyl sulfonate, denoted as mixed solution II; among them, the concentration of the sodium hydroxide solution is 2 mol / L, the concentration of the sodium carbonate solution is 0.5 mol / L, and the addition amount of sodium dodecyl sulfonate is 0.25 g.

[0150] Add mixed solutions I and II to another beaker simultaneously at a certain dropping rate and stir rapidly, where the dropping rate of mixed solution I is 40 ml / h. During the dropping process, control the dropping rate of mixed solution II to maintain the pH value of the reaction system within the range of 9-10, control the reaction temperature at 60 °C, and obtain mixed solution III after the dropping is completed.

[0151] Age the mixed solution III at 90 °C for 24 h, and then centrifuge to obtain a precipitate. Wash the precipitate with deionized water until neutral, finally wash it once with ethanol, then dry it in an oven at 85 °C for 12 h, and grind it into layered double hydroxide powder.

[0152] (2) Preparation of multi-component composite metal oxide desulfurizer

[0153] Transfer the layered double hydroxide powder obtained in step (1) into a muffle furnace, and calcine it at 500 °C for 8 h in an air atmosphere to obtain the composite metal oxide desulfurizer D1, where the heating rate is 2 °C / min. The calcined solid powder is pressed on a powder press. After pressing and crushing it into 20-40 mesh particles, it can be used for flue gas desulfurization reaction.

[0154] Comparative Example 2

[0155] A preparation method of a multi-component composite metal oxide desulfurizer provided in this comparative example specifically includes the following steps:

[0156] (1) Preparation of layered double hydroxides

[0157] Prepare 200 ml of a mixed solution of magnesium nitrate, zinc nitrate, aluminum nitrate, and cerium nitrate, denoted as mixed solution I; among them, the concentration of magnesium nitrate is 0.7425 mol / L, the concentration of zinc nitrate is 0.0075 mol / L, the concentration of aluminum nitrate is 0.21 mol / L, and the concentration of cerium nitrate is 0.04 mol / L.

[0158] Prepare 200 ml of a solution of sodium hydroxide and sodium carbonate, denoted as mixed solution II; among them, the concentration of the sodium hydroxide solution is 2 mol / L, and the concentration of the sodium carbonate solution is 0.5 mol / L.

[0159] Add mixed solutions I and II to another beaker simultaneously at a certain dropping rate and stir rapidly. Among them, the dropping rate of mixed solution I is 40 ml / h. During the dropping process, control the dropping rate of mixed solution II to maintain the pH value of the reaction system within the range of 9 - 10, control the reaction temperature at 60 °C, and obtain mixed solution III after the dropping is completed.

[0160] Age the mixed solution III at 90 °C for 24 h, and then perform centrifugal separation to obtain a precipitate. Wash the precipitate with deionized water until it is neutral, finally wash it once with ethanol, then dry it in an oven at 85 °C for 12 h, and grind it into a layered double hydroxide powder.

[0161] (2) Preparation of the multi-component composite metal oxide desulfurizer

[0162] Transfer the layered double hydroxide powder prepared in step (1) to a muffle furnace, and calcine it in an air atmosphere at 500 °C for 8 h to obtain a composite metal oxide desulfurizer D2, where the heating rate is 2 °C / min. After calcination, press the solid powder on a powder press, and after pressing and crushing it into particles with a mesh size of 20 - 40, it can be used for the flue gas desulfurization reaction.

[0163] The present invention will be further described below in combination with examples of activity evaluation.

[0164] Examples of activity evaluation:

[0165] The composition of the inlet raw material gas in this test is shown in Table 1, and the space velocity of the desulfurization reaction is 500 h -1 , and the desulfurization activity evaluation is carried out under the condition that the reaction temperature is 500 °C.

[0166] Table 1 Composition of the raw material gas

[0167]

[0168] The evaluation test begins. First, weigh 0.8 g of small particles with a particle size of 20 - 40 mesh. Uniformly load them into a fixed - bed micro - reactor according to certain rules, and fix them with quartz wool on the upper and lower layers. Also, weigh 2 g of quartz sand to dilute the desulfurizer.

[0169] During the evaluation process, the inlet gas flow rate and the SO 2 content are controlled by a mass flow meter, and the SO 2 content in the outlet gas is detected by a QGA quantitative gas analysis mass spectrometer from Hiden Company in the UK. By measuring parameters such as the SO 2 content C_in, C_out at the inlet and outlet, the reaction space velocity, and the desulfurization reaction time, etc., the desulfurization performance of the composite metal oxide desulfurizer is comprehensively evaluated, as shown in Table 2. When the SO 2 content in the reactor outlet is higher than 100 ppm, it is default that the desulfurizer has become inactivated. At this time, the sulfur capacity of the desulfurizer is called the breakthrough sulfur capacity, and the sulfur capacity is calculated by the following formula:

[0170]

[0171] Among them, S - breakthrough sulfur capacity;

[0172] m s —— The mass of SO 2 adsorbed on the desulfurizer during the evaluation test;

[0173] M - The mass of the loaded catalyst;

[0174] C 进 、C 出 —— The SO 2 content at the inlet and outlet of the experimental device, g / m 3 ;

[0175] S y —— The mass space velocity of the reaction gas during the experiment, h -1 ;

[0176] t - The time required for breakthrough during the test, h.

[0177] After adsorption saturation, switch to a regeneration gas stream of 10% H 2 / N 2 . The regeneration reaction temperature is 500 °C. When no sulfur - containing gas can be detected in the regeneration gas stream, the regeneration ends and enters the next adsorption stage. The regenerated gas (SO 2 、H 2 S、S) can be returned to the Claus sulfur recovery unit after condensing and separating liquid sulfur to further recover sulfur resources.

[0178] After analysis, due to the initial adsorption of SO 2The partially formed bulk sulfate cannot be reduced under the regeneration conditions, resulting in a relatively high initial sulfur capacity. In addition, some of the reduced metal sulfates are regenerated into metal oxides with adsorption activity. The presence of metal promoters can, to a certain extent, affect the sulfur capacity of the adsorbent and the gas composition regenerated by reduction.

[0179] Table 2 Desulfurization effect of the composite metal oxide desulfurizer prepared in the present invention

[0180]

[0181]

[0182] The specific embodiments described above further elaborate on the purpose, technical solutions, and beneficial effects of the present invention. It should be understood that the above are only specific embodiments of the present invention and are not used to limit the protection scope of the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included in the protection scope of the present invention.

Claims

1. A multi-component composite metal oxide flue gas desulfurizer, characterized in that, it comprises an active component, a precipitant and a surfactant; the active component comprises divalent metal and trivalent metal; the divalent metal comprises one or more of Mg, Ca, Sr, Ba, Zn, Mn, Cu, and the trivalent metal comprises one or more of Al, Cr, Fe, Ni, La, Ce, Pr; the active component metal exists in the reaction system in the form of a precursor salt, including one or more of metal sulfates, chlorides, nitrates and acetates; the precipitant comprises one or more of sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate; the surfactant is a water-soluble anionic surfactant, including one or more of sodium dodecylsulfonate, sodium dodecylbenzenesulfonate, cetyltrimethylammonium bromide, polydiallyldimethylammonium chloride, polyacrylic acid and its salts.

2. The multi-component composite metal oxide flue gas desulfurizer according to claim 1, characterized in that, the molar ratio of the divalent metal to the trivalent metal is 2-5:1; the concentration of the metal salt solution is 1 mol / L.

3. The multi-component composite metal oxide flue gas desulfurizer according to claim 1, characterized in that, the concentration of sodium hydroxide or potassium hydroxide is 1-2 mol / L, and the concentration of sodium carbonate or potassium carbonate is 0.2-0.6 mol / L.

4. The multi-component composite metal oxide flue gas desulfurizer according to claim 1, characterized in that, the addition amount of the surfactant is 5-25% of the molar amount of the active metal.

5. A method for preparing the multi-component composite metal oxide flue gas desulfurizer according to claim 1 by ball milling and recrystallization, characterized in that, it comprises the following steps: S1, preparing layered multi-metal hydroxide by co-precipitation method S11, mixing the metal active component precursor salt with water at room temperature to obtain a first slurry; S12, mixing the precipitant with water to obtain a second slurry; S13, at a certain temperature, mixing the first slurry and the second slurry at a certain dropping rate. After mixing, carry out aging treatment, filter to obtain a reaction mother liquor and a precipitate; wash, dry and grind the precipitate into powder to obtain layered multi-metal hydroxide; S2, two-step dry and wet ball milling: uniformly mix the layered multi-metal hydroxide obtained by co-precipitation with ball milling particles and carry out dry ball milling, add a certain amount of deionized water and continue ball milling to obtain a ball milling slurry; S3, recrystallization: mix the reaction mother liquor in step S13 with the ball milling slurry in step S2 according to a ratio, and add an appropriate amount of surfactant and stir evenly, place it in a high-pressure reaction kettle for dynamic crystallization reaction to obtain a reaction precipitate; S4, calcination: after washing, drying, grinding and calcining the above reaction precipitate, obtain the corresponding multi-component composite metal oxide desulfurizer.

6. The method for preparing the multi-component composite metal oxide flue gas desulfurizer by ball milling and recrystallization according to claim 5, characterized in that, In step S13, the temperature for the mixing reaction of the first slurry and the second slurry is 40 - 60 °C; the dropping rate of the first slurry is 20 - 50 ml / h, and the dropping rate of the second slurry is adjusted to maintain the pH of the reaction system at 8 - 10; the temperature for the aging treatment is 70 - 100 °C, and the aging time is 12 - 24 h.

7. A method for preparing a multi-component composite metal oxide flue gas desulfurizer by ball milling recrystallization according to claim 5, characterized in that in step S2, the mass ratio of the layered double hydroxide to the zirconia balls during the dry ball milling process is 60:1, and the ball milling time is 1 - 6 h; the amount of deionized water added during the wet ball milling process is 25 - 100 wt% of the amount of the layered double hydroxide.

8. A method for preparing a multi-component composite metal oxide flue gas desulfurizer by ball milling recrystallization according to claim 5, characterized in that in step S3, the ball milling slurry and the reaction mother liquor are mixed at a mass ratio of 1:10 - 30, the temperature for the dynamic recrystallization hydrothermal reaction is 70 - 100 °C, the crystallization time is 8 - 16 h, and the oven rotation speed is 50 - 100 rpm.

9. A method for preparing a multi-component composite metal oxide flue gas desulfurizer by ball milling recrystallization according to claim 5, characterized in that in step S4, the calcination temperature is 400 - 700 °C, the calcination time is 5 - 12 h, and the heating rate is 2 °C / min.

10. The application of the multi-component composite metal oxide flue gas desulfurizer according to any one of claims 1 - 4 or the multi-component composite metal oxide desulfurizer prepared by the ball milling recrystallization method according to any one of claims 5 - 9 in flue gas desulfurization.

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