Aluminum phosphate with selective scandium adsorption, its preparation method and application

Abstract

This invention provides aluminum phosphate for selectively adsorbing scandium, its preparation method, and its application. The preparation method includes the following steps: mixing phosphate, aluminum salt, precipitant, and water; adjusting the pH; and then carrying out a hydrothermal reaction. The aluminum phosphate prepared by the method provided by this invention has a spherical morphology, good adsorption performance, and high selectivity for scandium ions, with an adsorption and removal rate of scandium ions exceeding 90%. It can be used for the selective adsorption and separation of scandium ions, and the preparation process is simple and environmentally friendly.

Description

Technical Field

[0001] This invention belongs to the field of rare earth resource recycling technology, and relates to aluminum phosphate, and more particularly to aluminum phosphate that selectively adsorbs scandium, its preparation method and application. Background Technology

[0002] Rare earth elements, often referred to as "industrial vitamins," are crucial raw materials for applications in fluorescent lasers, new energy materials, special alloys, and electronic information, and are widely used in high-tech fields such as aerospace and defense. Scandium, a key rare earth raw material, is widely used in solid oxide fuel cells, lighting, and high-performance alloys, and is both valuable and expensive. However, scandium-rich deposits are scarce; scandium mainly originates from iron, aluminum, lanthanides, and other ore processing byproducts, and is typically separated by solvent extraction after ore pretreatment and leaching. The concentration of scandium separated from the parent ore is as low as 10. -4 Furthermore, the energy required for the extraction and processing of scandium is substantial, approximately 7 GJ / kg. -1 Its concentration is at least two orders of magnitude higher than that of the lanthanides. Therefore, developing new methods and materials for the selective and efficient adsorption and separation of scandium is of great significance.

[0003] The main methods for separating and extracting scandium ions include physical, chemical, and biological methods. Physicochemical methods include reverse osmosis, extraction, adsorption, ion exchange, and precipitation. Among these, adsorption has received widespread attention and research due to its advantages such as simple operation, large processing capacity, low energy consumption, and recyclable adsorbents. Currently, commonly used traditional adsorbents include zeolite, clay, activated carbon, montmorillonite, chitosan, fly ash, and lignin. However, traditional adsorbents suffer from small specific surface area, low adsorption capacity, slow adsorption rate, and poor selectivity. Furthermore, rare earth solutions contain large amounts of other rare earth ions such as lanthanum, cerium, gadolinium, terbium, and lutetium. Due to the similarity of rare earth ions, traditional adsorbents struggle to achieve efficient and selective adsorption of scandium ions and facilitate resource recovery. Therefore, providing a novel adsorbent material for achieving efficient and selective adsorption of scandium ions and its preparation method is currently one of the urgent technical problems to be solved.

[0004] CN116764607A discloses a modified adsorption resin and its application in the separation of scandium. The modified adsorption resin comprises a multi-component active agent and a polypropylene resin, obtained by grafting the multi-component active agent and the polypropylene resin. The components of the multi-component active agent include GO, PEI, and PAN nanofibers. By linking GO, PAN, and polypropylene monomers through PEI, the aforementioned multi-component active agent can be inserted into the interior and exterior of the formed polypropylene resin macropores, providing more binding sites and thus further enhancing the adsorption capacity. This resin has a large adsorption capacity for scandium, but its selectivity still needs to be improved.

[0005] CN106732462A discloses a method for preparing a sandwich-structured magnetic mesoporous imprinted material capable of separating scandium. Superparamagnetic Fe3O4 nanoclusters were synthesized via a hydrothermal method. Combined with a hexadecyltrimethylammonium bromide template method, using scandium ions as template ions and functionalized siloxanes as functional monomers, a molecularly imprinted mesoporous material with a certain selectivity for scandium ions was synthesized using a silicate sol-gel method. The material has the advantages of high adsorption capacity and easy separation; however, the preparation method is complex and costly, making it difficult to apply in practical engineering.

[0006] CN116889863A discloses a method for preparing a silicon-based tributyl phosphate resin for adsorbing scandium. Using porous silica-like carrier particles as a framework and tributyl phosphate as a raw material, the silicon-based tributyl phosphate resin is synthesized using vacuum filling molding technology, and can adsorb scandium. CN105622764A discloses a phosphate-modified cellulose adsorbent, its preparation method, and its application in rare earth recovery. The prepared phosphate-modified cellulose adsorbent can be used for selective adsorption of scandium. Both of these methods produce high-molecular-weight scandium adsorbents, but the preparation methods are relatively cumbersome, and the organic reactions are prone to generating side reactions that affect the yield.

[0007] Therefore, it is crucial to develop a scandium ion adsorbent material with a simple preparation method, environmentally friendly preparation process, good selectivity, and large adsorption capacity, as well as its preparation method. Summary of the Invention

[0008] The purpose of this invention is to provide aluminum phosphate that selectively adsorbs scandium, its preparation method and application. The aluminum phosphate has strong selectivity and excellent adsorption capacity, and can be widely used for efficient selective adsorption, extraction and separation of scandium ions.

[0009] To achieve this objective, the present invention adopts the following technical solution:

[0010] In a first aspect, the present invention provides a method for preparing aluminum phosphate that selectively adsorbs scandium, the method comprising the following steps:

[0011] Phosphate, aluminum salt, precipitant, and water are mixed, and after adjusting the pH, a hydrothermal reaction is carried out.

[0012] The preparation method provided by this invention is simple and environmentally friendly, requires no dispersant, and produces aluminum phosphate with strong selective adsorption capacity, which can be widely used for the efficient selective adsorption, extraction and separation of scandium ions.

[0013] Preferably, the phosphate includes any one or a combination of at least two of sodium phosphate, potassium phosphate, sodium dihydrogen phosphate, potassium dihydrogen phosphate, disodium hydrogen phosphate, or dipotassium hydrogen phosphate. Typical but non-limiting combinations include combinations of sodium phosphate and potassium phosphate, sodium dihydrogen phosphate and potassium dihydrogen phosphate, sodium phosphate and potassium dihydrogen phosphate, potassium phosphate and sodium dihydrogen phosphate, sodium phosphate, sodium dihydrogen phosphate and dipotassium hydrogen phosphate, or potassium phosphate, potassium dihydrogen phosphate and disodium hydrogen phosphate.

[0014] Preferably, the aluminum salt includes any one or a combination of at least two of aluminum chloride, aluminum nitrate, or aluminum sulfate. Typical but non-limiting combinations include combinations of aluminum chloride and aluminum nitrate, combinations of aluminum nitrate and aluminum sulfate, combinations of aluminum chloride and aluminum sulfate, or combinations of aluminum chloride, aluminum nitrate, and aluminum sulfate.

[0015] Preferably, the precipitant comprises urea.

[0016] Preferably, the mass ratio of the aluminum salt to the phosphate is 1:(0.1-2), for example, it can be 1:0.1, 1:0.2, 1:0.4, 1:0.5, 1:0.6, 1:0.8, 1:1, 1:1.2, 1:1.4, 1:1.5, 1:1.6, 1:1.8 or 1:2, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0017] Preferably, the mass ratio of the aluminum salt to the precipitant is 1:(0.1-2), for example, it can be 1:0.1, 1:0.2, 1:0.4, 1:0.5, 1:0.6, 1:0.8, 1:1, 1:1.2, 1:1.4, 1:1.5, 1:1.6, 1:1.8 or 1:2, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0018] The present invention preferably controls the mass ratio of the aluminum salt to the phosphate and the precipitant within a specific range, which can increase the yield of aluminum phosphate and prevent waste of raw materials.

[0019] Preferably, the mass ratio of the sum of the aluminum salt, phosphate, and precipitant to water is 1:(10-100), for example, it can be 1:10, 1:20, 1:40, 1:50, 1:60, 1:80 or 1:100, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0020] Preferably, the mixing temperature is 15-40°C, for example, it can be 15°C, 20°C, 25°C, 30°C, 35°C or 40°C, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0021] Preferably, the mixing time is 5-30 minutes, for example, 5 minutes, 10 minutes, 15 minutes, 20 minutes, 25 minutes or 30 minutes, but not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0022] Preferably, the mixing method includes stirring.

[0023] Preferably, the stirring speed is 300-900 rpm, for example, it can be 300 rpm, 400 rpm, 500 rpm, 600 rpm, 700 rpm, 800 rpm or 900 rpm, but is not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0024] Preferably, the pH-adjusting agent includes nitric acid.

[0025] Preferably, the endpoint pH value for pH adjustment is 1-3, for example, it can be 1, 1.2, 1.4, 1.5, 1.6, 1.8, 2, 2.2, 2.4, 2.5, 2.6, 2.8 or 3, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0026] Preferably, the temperature of the hydrothermal reaction is 120-200℃, for example, it can be 120℃, 130℃, 140℃, 150℃, 160℃, 170℃, 180℃, 190℃ or 200℃, but is not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0027] Preferably, the hydrothermal reaction time is 3-48 hours, for example, it can be 3 hours, 5 hours, 10 hours, 15 hours, 20 hours, 25 hours, 30 hours, 35 hours, 40 hours, 45 hours or 48 hours, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0028] Preferably, after the hydrothermal reaction, solid-liquid separation and drying are performed sequentially.

[0029] Preferably, the drying temperature is 50-100℃, for example, it can be 50℃, 60℃, 70℃, 80℃, 90℃ or 100℃, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0030] Preferably, the drying time is 6-12 hours, for example, 6 hours, 7 hours, 8 hours, 9 hours, 10 hours, 11 hours or 12 hours, but not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0031] As a preferred embodiment of the preparation method provided by the present invention, the preparation method includes the following steps:

[0032] (1) Mix aluminum salt, phosphate and urea with water at a mass ratio of 1:(0.1-2):(0.1-2), and the mass ratio of the sum of aluminum salt, phosphate and urea to water is 1:(10-100). Stir at 300-900 rpm for 5-30 minutes at 15-40℃. Add nitric acid to adjust the pH to 1-3 to obtain a homogeneous solution.

[0033] (2) The obtained homogeneous solution is added to a hydrothermal reactor and reacted at 120-200℃ for 3-48h. After filtration and washing, the obtained solid is dried at 50-100℃ for 6-12h to obtain the aluminum phosphate.

[0034] Secondly, the present invention provides aluminum phosphate, which is prepared by the preparation method described in the first aspect.

[0035] The aluminum phosphate provided by this invention has a spherical morphology with a diameter ranging from 0.05 to 2 μm. It contains phosphate groups and hydroxyl groups and has adsorption properties for rare earth ions. Scandium ions have the smallest ionic radius among rare earth elements. Therefore, Sc(III) is the hardest Lewis acid among rare earth elements. The aluminum phosphate prepared by this invention can form a stable complex with scandium ions and has good selective adsorption properties for scandium ions.

[0036] Thirdly, the present invention provides an application of the aluminum phosphate described in the second aspect, wherein the aluminum phosphate is used to adsorb scandium ions.

[0037] Compared with the prior art, the present invention has the following beneficial effects:

[0038] The aluminum phosphate prepared by the method provided by this invention has a spherical morphology, good adsorption performance, and high selectivity for scandium ions. In particular, the adsorption and removal rate of scandium ions can reach more than 90%. It can be used for selective adsorption and separation of scandium ions. The preparation process is simple and environmentally friendly. Attached Figure Description

[0039] Figure 1 This is a scanning electron microscope image of aluminum phosphate prepared in Example 1 of the present invention.

[0040] Figure 2 This is an X-ray diffraction pattern of aluminum phosphate prepared in Example 1 of this invention.

[0041] Figure 3 This is the infrared spectrum of aluminum phosphate prepared in Example 1 of this invention.

[0042] Figure 4 This is the N2 adsorption-desorption curve of aluminum phosphate prepared in Example 1 of the present invention.

[0043] Figure 5This is a pore size distribution curve of aluminum phosphate prepared in Example 1 of the present invention. Detailed Implementation

[0044] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention in any way.

[0045] Example 1

[0046] This embodiment provides a method for preparing aluminum phosphate, the method comprising the following steps:

[0047] (1) Mix aluminum salt, phosphate and urea with water in a mass ratio of 1:1:1, where the mass of water is 50 times the sum of aluminum salt, phosphate and urea. Stir at 600 rpm for 20 min at 25°C. Add nitric acid to adjust the pH to 2 to obtain a homogeneous solution.

[0048] (2) After the obtained homogeneous solution was hydrothermally reacted at 160℃ for 24h, the solid was separated and dried at 60℃ for 12h to obtain aluminum phosphate.

[0049] Example 2

[0050] This embodiment provides a method for preparing aluminum phosphate, the method comprising the following steps:

[0051] (1) Aluminum salt, phosphate and urea are mixed with water in a mass ratio of 1:0.1:0.1, and the mass of water is 10 times the sum of aluminum salt, phosphate and urea. The mixture is stirred at 300 rpm for 30 min at 15℃. Nitric acid is added to adjust the pH to 3 to obtain a homogeneous solution.

[0052] (2) After the obtained homogeneous solution was hydrothermally reacted at 120°C for 48 hours, the solid was separated and dried at 50°C for 12 hours to obtain aluminum phosphate.

[0053] Example 3

[0054] This embodiment provides a method for preparing aluminum phosphate, the method comprising the following steps:

[0055] (1) Mix aluminum salt, phosphate and urea with water in a mass ratio of 1:2:2, where the mass of water is 100 times the sum of aluminum salt, phosphate and urea. Stir at 900 rpm for 5 min at 40℃, add nitric acid to adjust the pH to 1, and obtain a homogeneous solution.

[0056] (2) After the obtained homogeneous solution was hydrothermally reacted at 200℃ for 3 hours, the solid was separated and dried at 100℃ for 6 hours to obtain aluminum phosphate.

[0057] Example 4

[0058] This embodiment provides a method for preparing aluminum phosphate. Compared with Example 1, the pH is adjusted to 1 in step (1), and the rest is the same as in Example 1.

[0059] Example 5

[0060] This embodiment provides a method for preparing aluminum phosphate. Compared with Example 1, the temperature of the hydrothermal reaction in step (2) is 120°C, and the rest is the same as in Example 1.

[0061] Example 6

[0062] This embodiment provides a method for preparing aluminum phosphate. Compared with Example 1, the hydrothermal reaction time in step (2) is 3 hours, and the rest is the same as in Example 1.

[0063] Example 7

[0064] This embodiment provides a method for preparing aluminum phosphate. Compared with Example 1, the pH is adjusted to 0.5 in step (1), and the rest is the same as in Example 1.

[0065] Example 8

[0066] This embodiment provides a method for preparing aluminum phosphate. Compared with Example 1, the pH is adjusted to 4 in step (1), and the rest is the same as in Example 1.

[0067] Example 9

[0068] This embodiment provides a method for preparing aluminum phosphate. Compared with Example 1, the temperature of the hydrothermal reaction in step (2) is 100°C, and the rest is the same as in Example 1.

[0069] Example 10

[0070] This embodiment provides a method for preparing aluminum phosphate. Compared with Example 1, the temperature of the hydrothermal reaction in step (2) is 220°C, and the rest is the same as in Example 1.

[0071] Example 11

[0072] This embodiment provides a method for preparing aluminum phosphate. Compared with Example 1, the hydrothermal reaction time in step (2) is 2 hours, and the rest is the same as in Example 1.

[0073] Example 12

[0074] This embodiment provides a method for preparing aluminum phosphate. Compared with Example 1, the hydrothermal reaction time in step (2) is 50 h, and the rest is the same as in Example 1.

[0075] Comparative Example 1

[0076] This comparative example provides aluminum phosphate, which is commercially available aluminum phosphate (CAS: 7784-30-7).

[0077] Depend on Figures 1 to 5 As can be seen, the aluminum phosphate prepared by this invention exhibits a spherical structure, belonging to an amorphous material. The aluminum phosphate contains a large number of phosphate functional groups, and its specific surface area is 30 m². 2 / g, with an average pore size of 21.6nm.

[0078] The aluminum phosphate materials provided in the examples and comparative examples were placed in conical flasks. 50 mL of a mixed rare earth ion solution containing 5 mg / L each of scandium (Sc), lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), lutetium (Lu), and yttrium (Y) was added to the conical flasks. After sonication for 30 s, the solution was shaken on a constant temperature shaker at a oscillation rate of 150 rpm for 12 h. After filtration, the ion concentration in the solution was detected using an ICP-OES instrument. The adsorption and removal effect of each material on scandium ions was calculated, and the results are listed in Tables 1 and 2.

[0079] Table 1

[0080]

[0081]

[0082] Table 2

[0083]

[0084] As can be seen from Tables 1 and 2:

[0085] The aluminum phosphate prepared by the method provided in this invention exhibits high selectivity and good adsorption effect for scandium ions in a mixed rare earth ion solution. Under the preferred preparation conditions of this invention, the adsorption and removal rate of scandium ions by aluminum phosphate in the presence of other rare earth elements reaches over 90%. During preparation, if the pH value is too high, phosphate functional groups cannot be effectively formed on the surface of aluminum phosphate, resulting in a lower adsorption capacity and removal rate for rare earth ions. If the pH value is too low, it will inhibit the hydrolysis of aluminum ions and reduce Al(OH)₂ levels. 2+ The content, and Al(OH) 2+As a component of Al(OH)3 monomer, aluminum phosphate is formed slowly when the pH is too low. If the hydrothermal temperature is too high or the hydrothermal time is too long, spherical aluminum phosphate cannot be formed and instead flake aluminum phosphate is formed. The stacking makes it difficult to fully expose the adsorption sites, resulting in a reduced adsorption capacity for scandium ions. If the hydrothermal temperature is too low or the hydrothermal time is too short, aluminum phosphate cannot be effectively formed, resulting in weak selectivity of aluminum phosphate for scandium ions, small adsorption capacity, and low adsorption removal rate.

[0086] Compared to Example 1, the commercial aluminum phosphate in Comparative Example 1 showed weak selectivity for scandium ions and a low adsorption removal rate.

[0087] In summary, the aluminum phosphate prepared by the method provided by this invention has a spherical morphology, good adsorption performance, and high selectivity for scandium ions. In particular, the adsorption and removal rate of scandium ions can reach more than 90%. It can be used for the selective adsorption and separation of scandium ions. The preparation process is simple and environmentally friendly.

[0088] The applicant declares that the above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.

Claims

1. An application of aluminum phosphate in the selective adsorption of scandium ions, characterized in that, The method for preparing aluminum phosphate includes the following steps: Phosphate, aluminum salt, precipitant and water are mixed, the pH is adjusted to 1-3, and then a hydrothermal reaction is carried out at 120-200℃ for 3-48 hours.

2. The application according to claim 1, characterized in that, The phosphate includes any one or a combination of at least two of sodium phosphate, potassium phosphate, sodium dihydrogen phosphate, potassium dihydrogen phosphate, disodium hydrogen phosphate, or dipotassium hydrogen phosphate.

3. The application according to claim 1, characterized in that, The aluminum salt includes any one or a combination of at least two of aluminum chloride, aluminum nitrate, or aluminum sulfate.

4. The application according to claim 1, characterized in that, The precipitant includes urea.

5. The application according to claim 1, characterized in that, The mass ratio of the aluminum salt to the phosphate is 1:(0.1-2).

6. The application according to claim 1, characterized in that, The mass ratio of the aluminum salt to the precipitant is 1:(0.1-2).

7. The application according to claim 1, characterized in that, The mass ratio of the sum of the aluminum salt, phosphate, and precipitant to water is 1:(10-100).

8. The application according to claim 1, characterized in that, The mixing temperature is 15-40℃.

9. The application according to claim 1, characterized in that, The mixing time is 5-30 minutes.

10. The application according to claim 1, characterized in that, The mixing method includes stirring.

11. The application according to claim 10, characterized in that, The stirring speed is 300-900 rpm.

12. The application according to claim 1, characterized in that, The pH-adjusting reagent includes nitric acid.

13. The application according to claim 1, characterized in that, The hydrothermal reaction is followed by solid-liquid separation and drying.

14. The application according to claim 13, characterized in that, The drying temperature is 50-100℃.

15. The application according to claim 13, characterized in that, The drying time is 6-12 hours.

16. The application according to claim 1, characterized in that, The preparation method includes the following steps: (1) Mix aluminum salt, phosphate and urea with water at a mass ratio of 1:(0.1-2):(0.1-2), and the mass ratio of the sum of aluminum salt, phosphate and urea to water is 1:(10-100). Stir at 300-900 rpm for 5-30 min at 15-40℃. Add nitric acid to adjust the pH value to 1-3 to obtain a homogeneous solution. (2) The obtained homogeneous solution is added to a hydrothermal reactor and reacted at 120-200℃ for 3-48h. After filtration and washing, the obtained solid is dried at 50-100℃ for 6-12h to obtain the aluminum phosphate.

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