Method and device for preparing aluminum adsorbent powder
The preparation of lithium aluminum hydrotalcite powder by co-precipitation method through impact flow micro-mix technology has solved the problems of uneven particle size distribution and unstable yield quality, and achieved efficient and low-cost preparation of aluminum-based adsorbent powder, which has improved the efficiency and stability of lithium extraction projects.
Patent Information
- Application Number
- CN202510349705.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-24
- Publication Date
- 2025-07-11
AI Technical Summary
When preparing lithium-aluminum hydrotalcite powder materials with existing co-precipitation methods, the particle size distribution is uneven, the material adsorption performance is unstable, and the yield and quality are easily affected by the preparation conditions, resulting in poor product consistency and stability.
Impact flow micro-mixing technology is used to form a turbulent zone through two or more reaction liquids impacting each other at high speed, instantaneous uniform mixing of reactants is achieved, crystal nucleus formation and growth are controlled, particle size and morphology are accurately regulated, and aluminum-based adsorbent powder is prepared in combination with constant temperature stirring, filtration washing and drying steps.
It significantly improves the quality and production efficiency of powder materials, reduces energy consumption, ensures product consistency and adsorption performance, reduces production costs, and provides efficient and environmentally friendly lithium extraction solutions.
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Figure CN120285941A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to a method and device for preparing an aluminum-based adsorbent powder, belonging to the field of adsorbent manufacturing. Background Art
[0002] The lithium adsorption technology has become the most widely used mainstream lithium extraction technology in China's salt lake lithium extraction project due to its advantages such as good stability, green and environmental protection process, wide adaptability to brine, and high lithium ion selectivity. The largest industrial-scale lithium adsorbent material on the market is an aluminum-based lithium adsorbent, and its core component is a lithium aluminum hydrotalcite powder material. Currently, there are many methods for preparing this powder material. Among them, the co-precipitation method has become one of the most commonly used methods for preparing powders due to its excellent powder quality, simple method, low cost, and easy large-scale production. The co-precipitation process mainly consists of three steps: chemical reaction, crystal nucleus formation, and crystal nucleus growth. Both crystal nucleus formation and crystal nucleus growth occur in a supersaturated solution, and the solution supersaturation is generated by the material concentration and mixing condition in the reaction vessel. Therefore, controlling the mixing situation between the materials in the reactor is crucial for the performance of the products prepared by the co-precipitation method. In the process of preparing lithium aluminum hydrotalcite powder material by the co-precipitation method, due to the differences in the concentration and precipitation rate during precipitation between components with different particle sizes, it may lead to an uneven particle size distribution of the lithium aluminum hydrotalcite precipitate and unstable adsorption performance of the material. In addition, the yield and quality of the lithium aluminum hydrotalcite powder prepared by the co-precipitation method are easily affected by preparation conditions such as temperature, pH value, and stirring speed. Minor changes in these factors may cause fluctuations in yield and quality, thus affecting the stability and consistency of the products.
[0003] The impinging stream micromixing technology is an efficient mixing technology based on the impinging stream principle. Its principle is that two or more fluid streams (including homogeneous and heterogeneous fluid streams, such as gas-solid, gas-liquid, liquid-liquid combinations, etc.) impinge on each other at a certain angle at high speed, forming an impinging zone with high turbulence and extremely high particle concentration. During the impinging process, the kinetic energy of the fluid is fully utilized, generating a large amount of turbulence and shear force, which greatly enhances the interphase transfer process and mixing effect, promotes the instantaneous uniform mixing of reactants, accelerates the crystal nucleus formation process, can generate finer, larger specific surface area, and more uniform particles, and at the same time helps to precisely control the size and morphology of the precipitate particles, improving product consistency. In addition, since the turbulence and shear force generated by the impinging stream can fully utilize the kinetic energy of the fluid, the impinging stream micromixing technology has obvious advantages in terms of energy consumption compared with the traditional reaction kettle precipitation process. Applying the impinging stream micromixing technology to the process of preparing aluminum-based lithium adsorbents can significantly improve the quality and production efficiency of the powder material. Summary of the Invention
[0004] To overcome the problems of low purity, unstable yield and quality of aluminum-based adsorbent powder prepared by the coprecipitation method, the present invention provides a method for preparing aluminum-based adsorbent powder, including:
[0005] Mix lithium chloride monohydrate and aluminum chloride hexahydrate, and add water to dissolve to obtain reaction solution A;
[0006] Dissolve sodium hydroxide in water to obtain reaction solution B;
[0007] Use an impinging stream micromixer to mix the reaction solution A and the reaction solution B to obtain a mixed solution;
[0008] Stir the mixed solution through a constant temperature stirring system to obtain a suspension;
[0009] Filter the suspension to obtain a filter cake, and then rinse and dry it to obtain the aluminum-based adsorbent powder.
[0010] Further, the lithium chloride monohydrate and the aluminum chloride hexahydrate are mixed in a molar ratio of 0.6:1 to 1:1; the aluminum ion concentration in the reaction solution A is 0.2 to 0.5 mol / L.
[0011] Further, the hydroxide ion concentration in the reaction solution B is 0.2 to 1.1 mol / L.
[0012] Further, the flow rate in the impinging stream micromixer is 5 to 30 L / h, and the impinging angle is 70 to 90°.
[0013] Further, the stirring speed of the constant temperature stirring system is 200 to 500 rpm, the stirring temperature is 60 to 90 °C, and the stirring time is 4 to 12 h.
[0014] Further, the rinsing is carried out 3 to 5 times with deionized water.
[0015] Further, the drying temperature is 80 to 120 °C, and the time is 3 to 8 h.
[0016] The present invention also provides an apparatus for preparing aluminum-based adsorbent powder, including
[0017] A storage system;
[0018] An impinging stream micromixer;
[0019] A constant temperature stirring system;
[0020] The storage unit is connected to the impinging stream micromixer through a pipeline, and the impinging stream micromixer is connected to the constant temperature stirring system through a pipeline.
[0021] Further, the number of storage systems is two.
[0022] Furthermore, a pump is provided in the pipeline.
[0023] The beneficial effects of the present invention are as follows:
[0024] Applying the impinging stream micromixing technology to the process of preparing aluminum-based lithium adsorbents can significantly improve the quality and production efficiency of powder materials. Specifically, the impinging stream micromixing technology can play an important role in the key steps of the coprecipitation method, especially in the nucleation and crystal growth stages. In the chemical reaction stage, the aluminum salt and lithium salt solutions are efficiently mixed by the impinging stream micromixing technology. Two or more streams of solutions impinge on each other at high speed, forming a highly turbulent impinging zone. This strong mixing effect enables the reactants such as lithium ions, chloride ions, and aluminum ions in the system to reach a uniform distribution instantaneously, avoiding the situation of local concentration being too high or too low, thus creating ideal conditions for the subsequent formation of lithium-aluminum hydrotalcite nuclei. In the lithium-aluminum hydrotalcite nucleation stage, the impinging stream micromixing technology promotes the rapid mass transfer and uniform mixing between the reactants by generating a large amount of turbulence and shear force. This efficient mixing effect enables the lithium-aluminum hydrotalcite nuclei to form rapidly and uniformly in the supersaturated solution, avoiding the problems of uneven crystal nucleus size and distribution in traditional methods. Due to the application of the impinging stream technology, the lithium-aluminum hydrotalcite nuclei have smaller sizes and more uniform distributions, thus laying a good foundation for the subsequent crystal growth. In the lithium-aluminum hydrotalcite crystal growth stage, the impinging stream micromixing technology continues to play a role. By precisely controlling the flow rate and impinging angle of the impinging stream, the growth rate and direction of the lithium-aluminum hydrotalcite nuclei can be regulated, thereby achieving precise control over the particle size and morphology of the aluminum-based adsorbent powder. This precise control not only helps to generate finer particles with a larger specific surface area but also improves the product consistency, ensuring that each batch of aluminum-based lithium adsorbents has excellent performance. In addition, the impinging stream micromixing technology also has significant advantages in terms of energy consumption. Since this technology makes full use of the kinetic energy of the fluid and reduces the energy consumption of mechanical stirring in traditional reaction kettles, it can significantly reduce the production cost in large-scale production. At the same time, the efficient mixing effect also shortens the reaction time, further improving the production efficiency. In summary, applying the impinging stream micromixing technology to the process of preparing aluminum-based lithium adsorbents can not only improve the quality and consistency of the aluminum-based adsorbent powder materials but also significantly reduce the energy consumption and production cost. The application of this technology provides an efficient, environmentally friendly, and economical solution for the lithium extraction project from salt lakes and has broad application prospects. Description of the Drawings
[0025] Figure 1 It is a flowchart of an embodiment of the present invention.
[0026] Figure 2 It is a schematic diagram of the device for preparing aluminum-based adsorbent powder used in an embodiment of the present invention.
[0027] Figure 3 SEM images of the aluminum-based adsorbent powder prepared by the impinging stream micromixing process and the aluminum-based adsorbent powder prepared by the traditional stirring precipitation process of the present invention.
[0028] Figure 4 Particle size distribution data chart of the aluminum-based adsorbent nanopowder prepared by the impinging stream micromixing process and the traditional stirring precipitation process of the present invention.
[0029] Figure 5 XRD characterization chart of the aluminum-based adsorbent nanopowder prepared by the impinging stream micromixing process and the traditional stirring precipitation process of the present invention.
[0030] Figure 6 Data chart of the lithium extraction test by adsorption of the present invention. Detailed implementation mode
[0031] The present invention will be further described below in conjunction with the drawings and embodiments. The process of the embodiments of the present invention is as Figure 1 shown.
[0032] The device for preparing the aluminum-based adsorbent powder used in this embodiment is as Figure 2 shown, which includes an impinging stream micromixer a, a constant temperature stirring system b, a storage system c and a storage system d. In Examples 1-3, pipeline I is in the closed state and pipeline II is in the open state. In Comparative Example 1, pipeline I is in the open state and pipeline II is in the closed state.
[0033] Example 1
[0034] 1. Preparation of reaction solution A: Lithium chloride monohydrate and aluminum chloride hexahydrate are mixed at a molar ratio of 0.75:1, completely dissolved after adding water, and the aluminum ion concentration is controlled at 0.25 mol / L. After the reaction solution A is prepared, it is stored in the storage system;
[0035] 2. Preparation of reaction solution B: Sodium hydroxide is completely dissolved after adding water, and the hydroxide ion concentration is controlled at 0.75 mol / L. After the reaction solution B is prepared, it is stored in the storage system;
[0036] 3. The reaction solution A and the reaction solution B are respectively pumped from the storage system by pumps and fed into the two-side inlets of the impinging stream micromixer at a flow rate of 18 L / h, and the impinging angle is 75°. After the two reaction solutions are mixed, they flow into the constant temperature stirring system;
[0037] 4. In the constant temperature stirring system, the mixed solution is mechanically stirred at a speed of 300 rpm, the mixing temperature is maintained at 80 °C, and stirring is continued for 6 h;
[0038] 5. The obtained stirred suspension is filtered by a vacuum pump, and the obtained filter cake is washed 4 times with deionized water;
[0039] 6. Dry the filter cake in an oven at 100 °C for 5 h to finally obtain the aluminum-based adsorbent powder prepared by the impinging stream micromixing technology.
[0040] Example 2
[0041] 1. Preparation of reaction solution A: Mix lithium chloride monohydrate and aluminum chloride hexahydrate in a molar ratio of 0.6:1, completely dissolve them after adding water, control the aluminum ion concentration at 0.2 mol / L, and store the prepared reaction solution A in the storage system.
[0042] 2. Preparation of reaction solution B: Completely dissolve sodium hydroxide after adding water, control the hydroxide ion concentration at 0.2 mol / L, and store the prepared reaction solution B in the storage system.
[0043] 3. Pump reaction solution A and reaction solution B from the storage system respectively, feed them into the two-side inlets of the impinging stream micromixer at a flow rate of 5 L / h, with an impinging angle of 70°, and the two reaction solutions flow into the constant-temperature stirring system after mixing.
[0044] 4. Mechanically stir the mixed solution at a speed of 200 rpm in the constant-temperature stirring system, keep the mixing temperature at 60 °C, and continuously stir for 4 h.
[0045] 5. Filter the obtained stirred suspension with a vacuum pump, and wash the obtained filter cake 3 times with deionized water.
[0046] 6. Dry the filter cake in an oven at 80 °C for 3 h to finally obtain the aluminum-based adsorbent powder prepared by the impinging stream micromixing technology.
[0047] Example 3
[0048] 1. Preparation of reaction solution A: Mix lithium chloride monohydrate and aluminum chloride hexahydrate in a molar ratio of 1:1, completely dissolve them after adding water, control the aluminum ion concentration at 0.5 mol / L, and store the prepared reaction solution A in the storage system.
[0049] 2. Preparation of reaction solution B: Completely dissolve sodium hydroxide after adding water, control the hydroxide ion concentration at 1.1 mol / L, and store the prepared reaction solution B in the storage system.
[0050] 3. Pump reaction solution A and reaction solution B from the storage system respectively, feed them into the two-side inlets of the impinging stream micromixer at a flow rate of 30 L / h, with an impinging angle of 90°, and the two reaction solutions flow into the constant-temperature stirring system after mixing.
[0051] 4. Mechanically stir the mixed solution at a speed of 500 rpm in the constant-temperature stirring system, keep the mixing temperature at 90 °C, and continuously stir for 12 h.
[0052] 5. Filter the obtained stirred suspension with a vacuum pump, and wash the obtained filter cake 5 times with deionized water;
[0053] 6. Dry the filter cake in an oven for 8 h at a drying temperature controlled at 120 °C to finally obtain the aluminum-based adsorbent powder prepared by the impinging stream micromixing technology.
[0054] Comparative Example 1
[0055] 1. Preparation of reaction solution A: Mix lithium chloride monohydrate and aluminum chloride hexahydrate in a molar ratio of 0.75:1, completely dissolve them after adding water, control the aluminum ion concentration at 0.25 mol / L, and store the prepared reaction solution A in the storage system;
[0056] 2. Preparation of reaction solution B: Completely dissolve sodium hydroxide after adding water, control the hydroxide ion concentration at 0.75 mol / L, and store the prepared reaction solution B in the storage system;
[0057] 3. Pump reaction solution A and reaction solution B respectively from the storage system, and the two reaction solutions are mixed and flow into the constant-temperature stirring system;
[0058] 4. In the constant-temperature stirring system, mechanically stir the mixed solution at a speed of 300 rpm, keep the mixing temperature at 80 °C, and continuously stir for 6 h;
[0059] 5. Filter the obtained stirred suspension with a vacuum pump, and wash the obtained filter cake 4 times with deionized water;
[0060] 6. Dry the filter cake in an oven for 5 h at a drying temperature controlled at 100 °C to finally obtain the aluminum-based adsorbent powder prepared by the impinging stream micromixing technology.
[0061] Comparative Example 2
[0062] 1. Preparation of reaction solution A: Mix lithium chloride monohydrate and aluminum chloride hexahydrate in a molar ratio of 0.75:1, completely dissolve them after adding water, control the aluminum ion concentration at 0.25 mol / L, and store the prepared reaction solution A in the storage system;
[0063] 2. Preparation of reaction solution B: Completely dissolve sodium hydroxide after adding water, control the hydroxide ion concentration at 1.5 mol / L, and store the prepared reaction solution B in the storage system;
[0064] 3. Pump reaction solution A and reaction solution B respectively from the storage system, feed them from the two side inlets of the impinging stream micromixer at a flow rate of 18 L / h, the impinging angle is 75 °, and the two reaction solutions are mixed and flow into the constant-temperature stirring system;
[0065] 4. In the constant-temperature stirring system, mechanically stir the mixed solution at a speed of 300 rpm, keep the mixing temperature at 80 °C, and continuously stir for 6 h;
[0066] 5. Filter the obtained stirred suspension with a vacuum pump, and wash the obtained filter cake 4 times with deionized water;
[0067] 6. Dry the filter cake in an oven for 5 h, control the drying temperature at 100 °C, and finally obtain the aluminum-based adsorbent powder prepared by the impinging stream micromixing technology.
[0068] Comparative Example 3
[0069] 1. Preparation of reaction solution A: Mix lithium chloride monohydrate and aluminum chloride hexahydrate in a molar ratio of 0.3:1, completely dissolve them after adding water, control the aluminum ion concentration at 0.25 mol / L, and store the prepared reaction solution A in a storage system;
[0070] 2. Preparation of reaction solution B: Completely dissolve sodium hydroxide after adding water, control the hydroxide ion concentration at 0.75 mol / L, and store the prepared reaction solution B in a storage system;
[0071] 3. Pump reaction solution A and reaction solution B from the storage system respectively, feed them into the two side inlets of the impinging stream micromixer at a flow rate of 18 L / h, the impinging angle is 75°, and the two reaction solutions flow into a constant temperature stirring system after mixing;
[0072] 4. In the constant temperature stirring system, mechanically stir the mixed solution at a speed of 300 rpm, keep the mixing temperature at 80 °C, and continuously stir for 6 h;
[0073] 5. Filter the obtained stirred suspension with a vacuum pump, and wash the obtained filter cake 4 times with deionized water;
[0074] 6. Dry the filter cake in an oven for 5 h, control the drying temperature at 100 °C, and finally obtain the aluminum-based adsorbent powder prepared by the impinging stream micromixing technology.
[0075] The parameter comparison of the aluminum-based adsorbent powders prepared in Example 1, Example 2 and Example 3 is shown in Table 1.
[0076] Table 1
[0077] Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Comparative Example 3 Particle size range (nm) 50～120 150～200 200～300 400～600 300～420 350～480 Adsorption capacity (mg / g) 8.43 7.62 7.01 6.28 6.72 6.55
[0078] Figure 3 In (a) is the SEM image of the aluminum-based adsorbent powder prepared by the impinging stream micromixing process in Example 1 of the present invention, and (b) is the SEM image of the aluminum-based adsorbent powder prepared by the traditional stirring precipitation process in Comparative Example 1 of the present invention. Through Figure 3Comparing the two, it can be seen that the degree of crystal nucleus aggregation of the aluminum-based adsorbent prepared by the impinging stream micro-mixing process is significantly lower than that of the latter, and the formed crystal nucleus particle size is significantly smaller. At the same time, it also indirectly shows that compared with the aluminum-based adsorbent powder material prepared by the traditional stirring precipitation method, the aluminum-based lithium adsorbent powder prepared by the impinging stream micro-mixing technology has a higher surface energy, more active sites at the adsorbent interface, a higher specific surface area, and a stronger adsorption capacity.
[0079] Figure 4 In it, a is the particle size distribution data of the aluminum-based adsorbent nano-powder prepared by the impinging stream micro-mixing process in Example 1, and b is the particle size distribution data of the aluminum-based adsorbent nano-powder prepared by the traditional stirring precipitation process in Comparative Example 1. The results show that the nano-particles prepared by the impinging stream micro-mixing process are mainly concentrated between 50 and 300 nm, and the peak particle size is about 100 nm; while the particle size distribution of the aluminum-based adsorbent nano-particles synthesized by the traditional stirring precipitation process is relatively wide, distributed between 10 and 1000 nm, and the peak particle size is about 500 nm. Compared with the aluminum-based adsorbent powder material prepared by the traditional stirring precipitation method, the nano-particles prepared by the impinging stream micro-mixing process are significantly smaller in particle size and have a narrower particle size distribution range.
[0080] Figure 5 is the XRD characterization diagram of the aluminum-based adsorbent nano-powder prepared by the impinging stream micro-mixing process in Example 1 and the aluminum-based adsorbent nano-powder prepared by the traditional stirring precipitation process in Comparative Example 1. The results show that both materials can well match each peak on the aluminum-based adsorbent standard card PDF#51-0357, proving that both materials are effective crystal structures of aluminum-based adsorbent powders. The difference is that compared with the aluminum-based adsorbent nano-powder of the traditional stirring precipitation process, the main peak at 13.5° of the aluminum-based adsorbent nano-powder prepared by the impinging stream micro-mixing process is sharper, while the peaks at 23.4°, 47.2°, etc. are weaker, indicating that the particle size of the aluminum-based adsorbent powder synthesized by the impinging stream micro-mixing technology is smaller, the degree of crystallization is higher, and the proportion of amorphous materials is lower.
[0081] Comparison of Adsorption Capacity in Test Example 1
[0082] Taking the brine of Qinghai Dongtai Jinaier Salt Lake as an example, the aluminum-based adsorbents synthesized by the impinging stream micro-mixing process and the traditional stirring precipitation process are granulated and then subjected to lithium adsorption extraction tests under the same test system, and the changes in lithium adsorption capacity are monitored. The data are as Figure 6 shown. The results show that within 10 consecutive test cycles, the lithium adsorption capacity prepared by the impinging stream micro-mixing technology always remains between 2.3 and 2.5 g / L, while the capacity of the aluminum-based adsorbent prepared by the traditional stirring precipitation process is only 1.7 to 1.9 g / L. This experiment strongly confirms that the aluminum-based lithium adsorbent prepared by the impinging stream micro-mixing process has obvious advantages in lithium extraction capacity.
[0083] Test Example 2: Lithium Ion Selectivity Comparison
[0084] Taking the brine of Dongtai Jinaier Salt Lake in Qinghai as an example, the aluminum-based adsorbents prepared by the impinging stream micromixing process and the traditional stirring precipitation process were granulated and then subjected to lithium extraction tests under the same test system. By monitoring the water quality of the qualified solution for lithium extraction and analysis, the selective adsorption ability of the two adsorbents for lithium ions was judged. The data are shown in Table 2. The results show that in the qualified solution for lithium extraction and analysis of the adsorbent prepared by the impinging stream micromixing process, the impurity contents such as the magnesium-lithium ratio, boron-lithium ratio, sodium-lithium ratio, calcium-lithium ratio, and potassium-lithium ratio are all lower than those of the qualified solution for lithium extraction and analysis produced by the aluminum-based adsorbent prepared by the traditional stirring precipitation process, proving that the aluminum-based adsorbent prepared by the impinging stream micromixing process has great advantages in lithium ion selectivity, can significantly improve the efficiency of the whole-process lithium extraction process, and reduce the impurity treatment cost of the subsequent process.
[0085] Table 2
[0086]
Claims
1. A method for preparing an aluminum-based adsorbent powder, comprising: Mix lithium chloride monohydrate and aluminum chloride hexahydrate, and add water to dissolve to obtain reaction solution A; Dissolve sodium hydroxide in water to obtain reaction solution B; Use an impinging stream micromixer to mix the reaction solution A and the reaction solution B to obtain a mixed solution; Stir the mixed solution through a constant temperature stirring system to obtain a suspension; Filter the suspension to obtain a filter cake, and then rinse and dry it to obtain the aluminum-based adsorbent powder.
2. The method according to claim 1, wherein The lithium chloride monohydrate and aluminum chloride hexahydrate are mixed in a molar ratio of 0.6:1 to 1:1; the aluminum ion concentration in the reaction solution A is 0.2 to 0.5 mol / L.
3. The method according to claim 1, wherein The hydroxide ion concentration in the reaction solution B is 0.2 to 1.1 mol / L.
4. The method according to claim 1, wherein The flow rate in the impinging stream micromixer is 5 to 30 L / h, and the impinging angle is 70 to 90°.
5. The method according to claim 1, wherein The stirring speed of the constant temperature stirring system is 200 to 500 rpm, the stirring temperature is 60 to 90 °C, and the stirring time is 4 to 12 h.
6. The method according to claim 1, wherein The rinsing is performed by washing with deionized water 3 to 5 times.
7. The method according to claim 1, characterized in that, The drying temperature is 80 to 120 °C, and the time is 3 to 8 h.
8. An apparatus for preparing an aluminum-based adsorbent powder suitable for any one of the methods recited in claims 1-7, comprising: A storage system; An impinging stream micromixer; A constant temperature stirring system; The storage unit is connected to the impinging stream micromixer through a pipeline, and the impinging stream micromixer is connected to the constant temperature stirring system through a pipeline.
9. The device according to claim 8, wherein The number of storage systems is two.
10. The device according to claim 8, characterized in that A pump is provided in the pipeline.