Method for liquid-liquid two-phase reaction, liquid-liquid two-phase reaction apparatus, and use

Abstract

The present application relates to the field of liquid-liquid two-phase reaction, and discloses a kind of liquid-liquid two-phase reaction method, liquid-liquid two-phase reaction device and application, the method includes: in the one side of permeation medium and set up the first region containing first reactant, in the other side of permeation medium and set up the second region containing second reactant;The pressure P1 of setting the first region is less than the pressure P2 of the second region;Under the action of pressure difference between pressure P1 and pressure P2, the second reactant passes through the permeation medium, contacts the first reactant and reacts;The first reactant is the first liquid phase reactant, and the second reactant is the second liquid phase reactant.The method provided by the present application controls the suction force between the two-phase reaction zone, and then controls the reaction speed, ensures that the reactants are efficiently mixed and reacted, shortens the total reaction time, does not need to dilute the reactants by a large multiple, effectively reduces the cost of reactant materials, and improves the reaction efficiency.

Description

Technical Field

[0001] This invention relates to the field of liquid-liquid two-phase reactions, and more specifically to a method, apparatus and application of liquid-liquid two-phase reactions. Background Technology

[0002] In a large class of chemical reactions, the order and rate of reactant addition control the course of the reaction. For example, the target product C can only be obtained when solution A is added to solution B; conversely, adding solution B to solution A will not yield product C regardless of adjustments to other reaction conditions. The essence of this type of reaction is that, at the microscopic interface, the solute concentration in solution B must be much greater than that in solution A, with solute particles in solution A being encapsulated by solute particles in solution B. To ensure this reaction effect, the addition rate of A needs to be limited. A common solution is to dilute A by a large margin and / or slow down the addition rate of A as much as possible, while increasing the stirring speed to accelerate the diffusion of A in B. However, this leads to a series of adverse consequences: the overall reaction rate cannot be increased, resulting in low production efficiency; using extremely dilute solutions significantly increases the cost of treating the large amount of waste liquid generated after the reaction; and the increased material flow rate leads to a significant increase in energy consumption for stirring, pumping, and filtration.

[0003] In existing technologies, dripping is generally used for low-speed feeding scenarios. When slow dripping still cannot guarantee the uniformity of the local reaction or achieve the required low reactant concentration, the common approach is to further refine the droplets. For example, CN204469678U discloses a rotating distributing tank below the feeder's dripping port, which rotates with the stirring shaft to evenly disperse the dripped liquid onto the lower surface. CN209908460U discloses a pressurized spraying method. This mechanical droplet refining method has certain drawbacks; the sprayed fine droplets may re-collide and recombine into larger droplets, or the fine droplets may converge on the inner wall of the container and flow down in streams, failing to achieve a high degree of dispersion.

[0004] The paper "Preparation of α-Al₂O₃ Micropowder by Thermal Decomposition of Ammonium Aluminum Carbonate" (Fu Gaofeng et al., Chinese Journal of Nonferrous Metals, 1998, 9) discloses the preparation of ammonium aluminum carbonate crystals using ammonium aluminum sulfate and ammonium bicarbonate solutions. When the concentration of the ammonium bicarbonate solution is 2.5 mol / L, the addition rate of the ammonium aluminum sulfate solution cannot exceed a critical value of 0.55 L / h, approximately 1.84 mmol / min; exceeding this subcritical value will result in γ-aluminum hydroxide. Controlling the reaction to proceed in the predetermined direction while simultaneously improving production efficiency is key to efficiently obtaining the pure-phase target product in this type of synthesis reaction.

[0005] CN105107436B discloses a method for the continuous preparation of nano-oxide materials via membrane permeation hydrothermal process. This method utilizes membrane permeation to micro-mix salt solutions and precipitants at the micrometer or even submicrometer scale, aiming to obtain nano-oxide materials with controllable particle size. The method involves injecting a metal salt solution and a precipitant solution into a submerged double-ceramic membrane permeation reactor. Under the pressure difference across the membrane, the two solutions permeate through the ceramic membrane, undergoing a contact reaction. Essentially, this approach highly disperses two reactants (such as reactants A and B as described above) in a third medium. In essence, it still involves a large-scale dilution of the two reactants to control the physical scale of contact, combination, and precipitation (from the centimeter level to the micrometer level), thereby preparing nanoscale powders. Therefore, it cannot achieve an effect similar to the aforementioned "molecule A being encapsulated by molecule B," and thus cannot achieve the specific chemical reaction pathway. Summary of the Invention

[0006] The purpose of this invention is to address the problems in existing technologies, such as low production efficiency and excessive wastewater volume due to large-scale dilution or slow dropwise addition of reactants, excessive side reactions due to difficulty in precisely controlling reaction conditions, and excessively high implementation costs. This invention provides a liquid-liquid two-phase reaction method, a liquid-liquid two-phase reaction apparatus, and its application. The liquid-liquid two-phase reaction method utilizes negative pressure suction to control the feed of reactants, enabling simple adjustment of concentration ratios and dispersion methods, thereby achieving precise and efficient control of the reaction direction and rate.

[0007] To achieve the above objectives, a first aspect of the present invention provides a liquid-liquid two-phase reaction method, the method comprising:

[0008] A first zone containing a first reactant is set on one side of the permeation medium, and a second zone containing a second reactant is set on the other side of the permeation medium; the pressure P1 in the first zone is set to be less than the pressure P2 in the second zone;

[0009] Under the pressure difference between pressure P1 and pressure P2, the second reactant passes through the permeation medium and comes into contact with the first reactant to react.

[0010] The first reactant is a first liquid-phase reactant, and the second reactant is a second liquid-phase reactant.

[0011] A second aspect of the present invention provides a two-phase reaction apparatus, the apparatus comprising:

[0012] External reactor 1, wherein a stirring paddle 11 is provided at the bottom of the external reactor 1; and,

[0013] An inner reactor 2 is suspended within an outer reactor 1. The bottom of the inner reactor 2 has a mesh plate 21 that is recessed into the interior of the inner reactor, and a permeation medium is applied to the mesh plate 21.

[0014] The outer reactor 1 is used to fill the first reactant, and the inner reactor 2 is used to fill the second reactant; the first reactant is a first liquid-phase reactant, and the second reactant is a second liquid-phase reactant.

[0015] The third aspect of the present invention provides the application of the method described in the first aspect or the apparatus described in the second aspect in the preparation of ammonium aluminum carbonate.

[0016] The beneficial effects obtained by the present invention through the above technical solution are as follows:

[0017] (1) The liquid-liquid two-phase reaction method provided by this invention controls the suction force through the pressure difference between the two-phase reaction zones, thereby controlling the feed rate, reaction speed, and reaction uniformity. The larger the stirring speed n, the faster the reactant feed rate m, and the stronger the dispersion and mixing ability s of the stirring on the materials. The three variables n, m, and s are positively coupled. Only n needs to be adjusted to simultaneously ensure production efficiency (directly related to m) and production quality (directly related to s), that is, to improve reaction efficiency. Compared with the existing technology's approach of separate monitoring, independent control, and then electronic control linkage, it has the comprehensive advantages of fast response, easy implementation, and low cost.

[0018] (2) The liquid-liquid two-phase reaction method provided by the present invention can ensure that the concentration ratio of the first reactant to the second reactant at the reaction interface is large enough, without having to dilute the second reactant by a large ratio in advance, thus effectively improving production efficiency.

[0019] (3) The liquid-liquid two-phase reaction device provided by the present invention can conveniently adjust the interface size and reaction rate of the chemical reaction, so as to achieve the above two-phase reaction to maintain the ideal reactant concentration ratio and proceed according to the preset chemical reaction direction and maintain a high reaction rate, thereby ensuring product purity and improving production efficiency. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the two-phase reaction device used in the embodiments of the present invention;

[0021] Figure 2 These are the XRD patterns of ammonium aluminum carbonate prepared in Examples 1-5 and Comparative Examples 1-2 of this invention.

[0022] Explanation of reference numerals in the attached figures

[0023] 1. External reactor 2. Internal reactor

[0024] 3 Negative pressure cavity 11 Stirring paddle

[0025] 21 mesh Detailed Implementation

[0026] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0027] The first aspect of this invention provides a method for a liquid-liquid two-phase reaction, the method comprising:

[0028] A first zone containing a first reactant is set on one side of the permeation medium, and a second zone containing a second reactant is set on the other side of the permeation medium; the pressure P1 in the first zone is set to be less than the pressure P2 in the second zone;

[0029] Under the pressure difference between pressure P1 and pressure P2, the second reactant passes through the permeation medium and comes into contact with the first reactant to react.

[0030] The first reactant is a first liquid-phase reactant, and the second reactant is a second liquid-phase reactant.

[0031] According to the present invention, the two-phase reaction refers to a type of liquid-liquid two-phase reaction in which the second reactant can only be slowly added to the first reactant and cannot be reversed. The conditions for this type of reaction to occur are that the concentration of the first reactant is much greater than that of the second reactant at the microscopic interface, and the second reactant is in a state where it is encapsulated by the first reactant. Examples include the preparation of silica-alumina gel, a molecular sieve precursor, and the preparation of aluminum ammonium carbonate from aluminum ammonium sulfate. In the present invention, by adjusting the pressure difference between the first and second zones, the suction force can be controlled. This suction force, in turn, controls the feeding rate of the second reactant, thereby controlling the reaction rate and preventing local over-reaction or excessive side reactions caused by excessive or uneven feeding. The reaction rate is positively correlated with and well-matched to the reactant feeding rate and the reaction rate, effectively ensuring reactant mixing, improving the overall reaction rate, and enhancing reaction efficiency.

[0032] According to a preferred embodiment of the present invention, when the second reactant is a second liquid-phase reactant, the second reactant may further contain a solvent, preferably water. In the above embodiment, when the infiltration rate of the second reactant is sufficiently slow, the concentration of the second reactant at the reaction interface can be ensured to be sufficiently low, so that the chemical reaction proceeds in the predetermined direction without the need for large-scale dilution. Preferably, the second liquid-phase reactant is a saturated solution.

[0033] In this invention, there are no specific limitations on the material of the permeation medium, as long as it can achieve the permeation of the second reactant. For example, the permeation medium can be selected from at least one of filter paper, filter cloth, and filter membrane.

[0034] In this invention, the selection range for the pore size and pore density of the permeation medium is relatively wide, and it can be selected according to the actual requirements of the type of the second reactant and the reaction rate. Preferably, the pore size of the permeation medium is 100 mesh-400 mesh, and more preferably 200 mesh-300 mesh. By adopting the above preferred embodiments, it can be ensured that the concentration of the second reactant relative to the first reactant at the reaction interface is sufficiently low, eliminating the need for large-scale dilution of the reactants and effectively reducing the cost of reactant materials.

[0035] According to the present invention, the range of possible methods for forming the pressure difference between pressure P1 and pressure P2 is relatively wide. For example, the pressure difference between the first and second regions can be formed by forming a negative pressure in the first region or a positive pressure in the second region.

[0036] According to a preferred embodiment of the present invention, the pressure difference between pressure P1 and pressure P2 is achieved by applying stirring to the first reactant, causing the liquid surface of the first reactant to sink and form a vortex, creating a negative pressure in the first region, thereby creating a pressure difference between the concave liquid surface and the second region. Using this preferred embodiment, the dispersing and mixing effect of the stirring is positively matched with the feed rate, eliminating the need for additional monitoring and control linkage devices, which simplifies the structure and operation and reduces implementation costs.

[0037] In this invention, when a pressure difference is formed by stirring, the stirring speed is not less than 180 rpm, more preferably 200-800 rpm, and even more preferably 500-700 rpm. If the stirring speed is too low, it may be difficult to form a pressure difference; if the stirring speed is too high, the volume of the negative pressure cavity is expanded, resulting in a stronger suction effect on the first reactant, and the feed is too fast, which may lead to insufficient reaction and affect the crystallinity of the product.

[0038] According to a preferred embodiment of the present invention, as the stirring speed increases, the liquid level of the first reactant continuously declines, and the stirring speed is positively correlated with the contact reaction rate of the reactants. Preferably, the second reactant reacts with the first reactant to obtain the reaction product. The contact reaction rate between the first and second reactants, based on the molar amount of the reaction product generated per unit time, is 1-2.2 mmol / min, preferably 1.3-2.1 mmol / min. At the above-mentioned preferred reaction rate, a sufficient amount of second reactant molecules can be ensured to exist around the first reactant molecules, which is beneficial for generating a high-purity target product.

[0039] A second aspect of the present invention provides a two-phase reaction apparatus, the apparatus comprising:

[0040] External reactor 1, wherein a stirring paddle 11 is provided at the bottom of the external reactor 1; and,

[0041] An inner reactor 2 is suspended within an outer reactor 1. The bottom of the inner reactor 2 has a mesh plate 21 that is recessed into the interior of the inner reactor, and a permeation medium is applied to the mesh plate 21.

[0042] The outer reactor 1 is used to fill the first reactant, and the inner reactor 2 is used to fill the second reactant; the first reactant is a first liquid-phase reactant, and the second reactant is a second liquid-phase reactant.

[0043] In this invention, there are no special restrictions on the size and shape of the outer and inner reactors, as long as the inner reactor can be placed inside the outer reactor. For example, both the outer and inner reactors can be independently selected from cylinders and / or cuboids, preferably cylinders.

[0044] According to a preferred embodiment of the present invention, the diameter ratio D:d of the outer reactor 1 and the inner reactor 2 is 1:0.5-0.9, preferably 1:0.7-0.8.

[0045] According to the present invention, the mesh plate is used to support the permeation medium. There are no special restrictions on the shape of the mesh plate, as long as it ensures that the first reactant and the second reactant do not directly contact each other. Preferably, the mesh plate 21 is at least one of a spherical arc surface, an ellipsoidal arc surface, and a conical surface, more preferably a spherical arc surface. In the above preferred embodiments, a larger macroscopic reaction interface can be provided.

[0046] According to a preferred embodiment of the present invention, the ratio of the arc height or cone height of the mesh plate to the radius of the inner reactor is 0.8-1.1:1, preferably 0.9-1:1.

[0047] In this invention, the arc height refers to the shortest distance from the highest point of the spherical or ellipsoidal arc surface to the center of the projection circle, and the cone height refers to the shortest distance between the vertex of the cone and the center of the bottom surface of the cone.

[0048] According to a preferred embodiment of the present invention, the pore size of the mesh plate is larger than the pore size of the permeating medium. Preferably, the pore size of the mesh plate is 100-600 mesh, and the porosity is 31%-65%.

[0049] In this invention, the immersion depth of the inner reactor in the first reactant can be controlled by adjusting the suspension height, which means that the area of ​​the macroscopic interface where the chemical reaction occurs can be controlled.

[0050] According to a preferred embodiment of the present invention, the suspension height of the inner reactor 2 is such that the immersion depth h of the inner reactor in the first reactant satisfies the following quantitative relationship with the inner reactor diameter d, the outer reactor diameter D, and the liquid level height H of the first reactant: h = H × (Dd) / D.

[0051] According to a preferred embodiment of the present invention, the suspension height of the inner reactor 2 is such that the heights of the first reactant and the second reactant are level. In this preferred embodiment, without stirring, due to the balance of internal and external pressures, there will be no significant leakage of the first and second reactants, and the rate of material contact and mixing will depend almost entirely on the stirring rate, which is beneficial for precise control of the reaction rate.

[0052] The third aspect of the present invention provides the application of the method described in the first aspect or the apparatus described in the second aspect in the preparation of ammonium aluminum carbonate.

[0053] According to a preferred embodiment of the present invention, the preparation process of the aluminum ammonium carbonate includes:

[0054] A first zone containing a first reactant is set on one side of the permeation medium, and a second zone containing a second reactant is set on the other side of the permeation medium; the pressure P1 in the first zone is set to be less than the pressure P2 in the second zone;

[0055] Under the pressure difference between pressure P1 and pressure P2, the second reactant passes through the permeation medium, contacts the first reactant, and reacts. After the reaction is completed, the product is collected to obtain ammonium aluminum carbonate. The first reactant is a first liquid-phase reactant containing ammonium bicarbonate, and the second reactant is a second liquid-phase reactant containing aluminum nitrate and / or aluminum sulfate.

[0056] Preferably, the first reactant is obtained by dissolving ammonium bicarbonate in a solvent and adjusting the pH to 8.5-10 with ammonia water. More preferably, the concentration of ammonium bicarbonate in the first reactant is 2.4-2.6 mol / L.

[0057] Preferably, the second reactant is a saturated solution of aluminum nitrate and / or aluminum sulfate; more preferably, the second reactant also contains undissolved solid particles of aluminum nitrate and / or aluminum sulfate.

[0058] Preferably, the pressure difference between pressure P1 and pressure P2 is formed by applying stirring to the first reactant to form a vortex, thereby creating a negative pressure in the first zone. The stirring speed is 200-700 rpm. Preferably, the second reactant reacts with the first reactant to obtain the reaction product ammonium aluminum carbonate. The contact reaction rate between the first reactant and the second reactant is 1-2.2 mmol / min, based on the molar amount of ammonium aluminum carbonate generated per unit time.

[0059] Preferably, the reaction temperature is 40-60°C.

[0060] Preferably, the crystallinity of the aluminum ammonium carbonate is not less than 50%, and more preferably, the crystallinity of the aluminum ammonium carbonate is not less than 60%.

[0061] In this invention, the crystallinity is detected, analyzed and calculated by XRD, and the percentage of the integrated area of ​​the target product diffraction peak in the XRD spectrum to the total integrated area is recorded as the crystallinity.

[0062] Preferably, the preparation process of the aluminum ammonium carbonate further includes: after the reaction is completed, the obtained product is subjected to solid-liquid separation, washing, and drying to obtain aluminum ammonium carbonate powder. The solid-liquid separation, washing, and drying can be carried out using conventional operating methods in the art, and will not be described in detail here.

[0063] The present invention will be described in detail below through embodiments.

[0064] In the following embodiments, the reaction apparatus used is as follows: Figure 1 As shown, the outer reactor 1 has a diameter of 60 mm, and the inner reactor 2, which is suspended in the outer reactor 1, has a diameter of 45 mm. The bottom of the inner reactor 2 has a mesh plate 21 with an arc surface that is concave inward, with an arc height of 22.5 mm and an arc length of 45 mm. The mesh plate has a mesh size of 200 mesh and an opening rate of 55%.

[0065] In the following examples, all raw materials used were commercially available.

[0066] The phase composition of the reaction products was analyzed by XRD, and the crystallinity was calculated. The instrument used was a Rigaku D / max-2006 / PC with a scan step of 0.01° and a scan range of 2θ = 5°-90°. The XRD spectra were then processed by JADE 6.5 software for mineral qualitative analysis.

[0067] The percentage of the integrated area of ​​the target product diffraction peak in the XRD pattern to the total integrated area is denoted as the crystallinity.

[0068] Example 1

[0069] (1) Take 1 mol of ammonium bicarbonate and add 400 mL of water to prepare a 2.5 mol / L ammonium bicarbonate solution, and add concentrated ammonia to adjust the pH of the solution to 9 to obtain the first reactant. Transfer the first reactant as a whole into the external reactor.

[0070] (2) A filter cloth with a pore size of 200 mesh and an open porosity of 65% is laid on the mesh plate of the inner reactor. 0.25 mol of Al(NO3)3·9H2O powder is mixed with 60 mL of water and stirred until fully dissolved to obtain a saturated aluminum nitrate solution containing undissolved aluminum nitrate solid particles (the solid-liquid ratio exceeds its solubility), which is the second reactant. As the reaction proceeds, the solute of the second reactant gradually dissolves and is released to participate in the reaction. The second reactant is transferred into the inner reactor, and then the inner reactor is suspended and submerged in the center of the outer reactor, so that the liquid levels of the first reactant and the second reactant are level.

[0071] (3) Immediately turn on the stirring at 600 rpm and turn on the heating to raise the temperature of the first reactant to 50±5℃ to start the reaction.

[0072] The total reaction time was 3 hours, and the total rate of feed and reaction (based on the molar amount of ammonium aluminum carbonate) was approximately 1.39 mmol / min. All the reaction product in the external reactor was transferred out, filtered, washed, and dried at 100°C. The resulting solid powder was confirmed by XRD analysis to be pure-phase ammonium aluminum carbonate. The XRD pattern of the product is shown below. Figure 2 As shown in Table 1, the characteristic peak data and crystallinity data are shown in Table 1; the total volume of the filtered waste liquid is about 460 mL, which is the wastewater to be treated.

[0073] Example 2

[0074] The method was the same as in Example 1, except that the stirring speed in step (3) was 700 rpm, the total reaction time was 2.5 h, and the total rate of addition and reaction (based on the molar amount of aluminum ammonium carbonate) was approximately 1.67 mmol / min. The obtained solid powder was confirmed by XRD analysis to be pure phase aluminum ammonium carbonate, with crystallinity comparable to that of aluminum ammonium carbonate in Example 1. The XRD diffraction pattern of the product is shown in [reference needed]. Figure 2 The characteristic peak data and crystallinity data are shown in Table 1. The total volume of the filtered waste liquid is approximately 460 mL, which is the wastewater to be treated.

[0075] Example 3

[0076] The method was the same as in Example 1, except that the stirring speed in step (3) was 800 rpm, the total reaction time was 2 hours, and the total rate of addition and reaction (based on the molar amount of aluminum ammonium carbonate) was approximately 2.09 mmol / min. The obtained solid powder was confirmed by XRD analysis to be pure phase aluminum ammonium carbonate, but the crystallinity was lower than that of aluminum ammonium carbonate in Example 1. The XRD diffraction pattern of the product is shown in [reference needed]. Figure 2The characteristic peak data and crystallinity data are shown in Table 1. The total volume of the filtered waste liquid is approximately 460 mL, which is the wastewater to be treated. When the rotation speed is too high, the volume of the negative pressure cavity is expanded, resulting in a stronger suction effect on reactant 2, faster feeding, and insufficient reaction, which leads to a slightly lower crystallinity of ammonium aluminum carbonate.

[0077] Example 4

[0078] The method was the same as in Example 3, except that in step (2), 0.25 mol of Al(NO3)3·9H2O powder was replaced with 0.125 mol of Al2(SO4)3·18H2O. The total reaction time was 3 hours, and the total rate of addition and reaction (based on the molar amount of aluminum ammonium carbonate) was approximately 1.39 mmol / min. XRD analysis confirmed that the obtained solid powder was pure phase aluminum ammonium carbonate, with crystallinity comparable to that of aluminum ammonium carbonate in Example 3. The XRD diffraction pattern of the product is shown in [reference needed]. Figure 2 The characteristic peak data and crystallinity data are shown in Table 1. The total volume of the filtered waste liquid is approximately 500 mL, which is the wastewater to be treated.

[0079] Example 5

[0080] The method was the same as in Example 1, except that in step (2), a non-woven bag with a pore size of about 20-25 μm (about 100 mesh) was inserted into the inner reactor as a permeation medium. The total reaction time was 2 hours, and the total feeding and reaction rate (in terms of the molar amount of aluminum ammonium carbonate) was about 2.09 mmol / min. The obtained solid powder was confirmed by XRD analysis to be pure phase aluminum ammonium carbonate, but the crystallinity was lower than that of aluminum ammonium carbonate in Example 1. The XRD diffraction pattern of the product is shown in [reference needed]. Figure 2 The characteristic peak data and crystallinity data are shown in Table 1. The total volume of the filtered waste liquid is approximately 460 mL, which is the wastewater to be treated.

[0081] Comparative Example 1

[0082] (1) Take 1 mol of ammonium bicarbonate and add 400 mL of water to prepare a 2.5 mol / L ammonium bicarbonate solution, and add concentrated ammonia to adjust the pH of the solution to 9 to obtain the first reactant. Transfer the first reactant as a whole into the external reactor.

[0083] (2) Turn on the stirring in the external reactor at a speed of 800 rpm, and turn on the heating to keep the temperature of the first reactant at 50±5℃.

[0084] (3) Dissolve 0.25 mol of Al(NO3)3·9H2O powder completely in 1250 mL of water to prepare a saturated solution of 0.2 mol / L as the second reactant;

[0085] The second reactant was slowly added dropwise to the first reactant at a rate of 1.39 mmol / min, with a total addition time of approximately 3 hours. The reaction was then continued for another 3 hours with stirring and heating. The total addition and reaction rate was 0.69 mmol / min.

[0086] After the reaction was completed, all the reaction products in the external reactor were transferred out, filtered, washed, and dried at 100°C. The resulting solid powder was confirmed by XRD analysis to be an amorphous substance. The XRD diffraction pattern of the product is shown below. Figure 2 The characteristic peak data are shown in Table 1. The total volume of the filtered waste liquid is approximately 1700 mL, which is the wastewater to be treated.

[0087] The traditional method of slowly adding aluminum source solution dropwise to ammonium bicarbonate solution requires continuous stirring after the addition is complete to ensure a full reaction. This is particularly relevant in the case of NH4HCO3:Al 3+ At a lower molar ratio of 4, ammonium aluminum carbonate cannot be obtained, and the total reaction time is significantly longer, resulting in a significant increase in the amount of wastewater to be treated.

[0088] Comparative Example 2

[0089] Following the method in Comparative Example 1, the amount of ammonium bicarbonate in step (1) was increased to 2.5 mol, and the amount of water added was increased to 1000 mL to prepare a 2.5 mol / L ammonium bicarbonate solution as the first reactant. The dropping rate of the second reactant in step (3) was reduced to 1 mmol / min, and the total reaction time was 4.17 h. At this time, the obtained solid product was a non-pure phase ammonium aluminum carbonate containing some amorphous substances. The XRD diffraction pattern of the product is shown in [reference needed]. Figure 2 The characteristic peak data and crystallinity data are shown in Table 1.

[0090] Table 1

[0091]

[0092]

[0093] As can be seen from the above examples and comparative examples, the liquid-liquid two-phase reaction method provided by this invention controls the feeding rate, material contact effect, and type of reaction products by controlling the stirring speed, ultimately controlling production efficiency and product quality. In contrast, to achieve the same effect, existing technologies require large-scale dilution of reactants, leading to a significant increase in wastewater treatment costs, or the use of slow dripping methods, resulting in low production efficiency. Furthermore, the aluminum ammonium carbonate product prepared using the method provided by this invention exhibits high crystallinity.

[0094] The liquid-liquid two-phase reaction device provided by this invention is simple, easy to implement, and low in cost, and has comprehensive advantages in improving reaction efficiency.

[0095] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. The application of a liquid-liquid two-phase reaction method in the preparation of ammonium aluminum carbonate, characterized in that, The preparation method of this ammonium aluminum carbonate includes: A first zone containing a first reactant is set on one side of the permeation medium, and a second zone containing a second reactant is set on the other side of the permeation medium; the pressure P1 in the first zone is set to be less than the pressure P2 in the second zone; Under the pressure difference between pressure P1 and pressure P2, the second reactant passes through the permeation medium and comes into contact with the first reactant to react. The first reactant is a first liquid-phase reactant containing ammonium bicarbonate, and the second reactant is a second liquid-phase reactant containing aluminum nitrate and / or aluminum sulfate; The pressure difference between pressure P1 and pressure P2 is formed by applying stirring to the first reactant to create a vortex, thereby creating a negative pressure in the first region; the stirring speed is 500-700 rpm. The pore size of the permeation medium is 200-300 mesh.

2. The application according to claim 1, wherein, The permeation medium is selected from at least one of filter paper, filter cloth, and filter membrane.

3. The application according to claim 1 or 2, wherein, The second reactant reacts with the first reactant to obtain a reaction product. The reaction rate between the first reactant and the second reactant is 1-2.2 mmol / min, based on the molar amount of the reaction product generated per unit time.

4. In the application according to claim 3, the contact reaction rate between the first reactant and the second reactant is 1.3-2.1 mmol / min.

5. A liquid-liquid two-phase reaction apparatus for use in any one of claims 1-4, characterized in that, The device includes: An external reactor (1) is provided with a stirring paddle (11) at its bottom; and, An inner reactor (2) is disposed in an outer reactor (1), the bottom of the inner reactor (2) having a mesh plate (21) recessed into the interior of the inner reactor (2), and a permeation medium is applied to the mesh plate (21); The outer reactor (1) is used to fill the first reactant, and the inner reactor (2) is used to fill the second reactant; the first reactant is a first liquid-phase reactant, and the second reactant is a second liquid-phase reactant.

6. The apparatus according to claim 5, wherein, The diameter ratio of the outer reactor (1) and the inner reactor (2) is D:d=1:0.5-0.

9.

7. The apparatus according to claim 6, wherein, The diameter ratio D:d of the outer reactor (1) and the inner reactor (2) is 1:0.7-0.

8.

8. The apparatus according to claim 5, wherein, The mesh plate (21) is at least one of a spherical arc surface, an ellipsoidal arc surface, and a conical surface.

9. The apparatus according to claim 8, wherein, The mesh plate (21) is a spherical arc surface.

10. The apparatus according to claim 8, wherein, The ratio of the arc height or cone height of the mesh plate to the radius of the inner reactor is 0.8-1.1:

1.

11. The apparatus according to claim 5, wherein, The inner reactor (2) is suspended above the agitator (11), and the bottom of the inner reactor (2) faces the agitator (11).

12. The apparatus according to claim 5, wherein, The suspension height of the inner reactor (2) is such that the immersion depth h of the inner reactor in the first reactant satisfies the following quantitative relationship with the inner reactor diameter d, the outer reactor diameter D, and the liquid level height H of the first reactant: h = H × (Dd) / D.

13. The apparatus according to claim 5, wherein, The suspension height of the inner reactor (2) is such that the heights of the first reactant and the second reactant are level.

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