A microchannel extraction reactor with a grid insert and its application

Abstract

The present application relates to the field of microchannel equipment extraction technology, and in particular to a microchannel extraction reactor with a grid plug-in and its application; the microchannel extraction reactor comprises: a microchannel panel; an extraction unit; comprising a receiving tank, a linear microchannel, a front chamber and a rear chamber; a stainless steel filter group, comprising at least one slightly curved stainless steel filter arranged in the receiving tank, and the raised end of the slightly curved stainless steel filter is arranged toward the receiving tank, and the slightly curved stainless steel filter is arranged between the microchannel panel and the receiving tank; at least two adjustment units, comprising a sliding support sheet and an adjustment tank for accommodating the sliding support sheet, the sliding support sheet is extended and retracted through the adjustment tank, and one end of the sliding support sheet is fixedly connected to the slightly curved stainless steel filter. The microchannel extraction reactor can promote sufficient mass transfer of phosphoric acid at the extraction phase interface, so as to improve the separation effect of metal element impurities in the phosphoric acid raw material under different flow rate conditions.

Description

Technical Field

[0001] The present application relates to the field of microchannel equipment extraction technology, and in particular to a microchannel extraction reactor with a grid plug-in and its application. Background Art

[0002] Microchannel extraction technology boasts uniform dispersion of the water-oil phase, large droplet surface area, and rapid intra- and interphase mass transfer, resulting in high extraction efficiency. Therefore, it can be widely used in fields such as the extraction and separation of metal ions, organics, and inorganics. Currently, common microchannels can be divided into two types: active and passive. Active microchannel reactors incorporate active elements within their structures that enable precise control, monitoring, and regulation of the fluid within the microchannel. These reactors often offer advantages such as high flow control precision, high reaction efficiency, and controllable reaction conditions. However, active microchannel reactors are expensive to manufacture and difficult to integrate with other devices. Passive microchannel reactors, on the other hand, achieve micromixing through the shape and structure of the channel without the need for an external force field. These reactors can also achieve micromixing by introducing barriers into the microchannel to increase lateral liquid velocity, or by modifying the geometric three-dimensional structure of the microchannel reactor or inserting obstruction plugs to increase contact between the mixed liquids and thereby improve liquid uniformity. Therefore, passive microchannel reactors offer advantages over active microchannel reactors in terms of simpler structure, ease of fabrication, lower cost, rapid and uniform mass transfer, and ease of integration with other devices. At present, most of the research on the extraction of metal ions by passive microchannel reactors focuses on microextraction technologies that change the shape of the microchannel, such as T-type passive microchannel reactors and Y-type passive microchannel reactors.

[0003] The raw material for producing phosphoric acid is generally phosphate rock, which has a high impurity content and a wide variety of impurities, generally containing iron, aluminum, magnesium, fluorine, calcium, zinc, and organic matter. Therefore, when using this type of phosphate rock as a raw material for the production of phosphate, food-grade phosphoric acid, and electronic-grade phosphoric acid, it is difficult to meet the use requirements and must be purified first. If the above-mentioned T-type passive microchannel reactor and Y-type passive microchannel reactor are directly used for extraction, the particle size of the metal element impurities is small and difficult to separate through these traditional passive microchannel reactors, resulting in poor separation effect. At present, obstacles can be inserted into the passive microchannel reactor or baffles can be built on the microchannel wall to further reduce the distance between the separation channels of the dynamic microchannel reactor. However, the operation of obstacles or baffles in the passive microchannel reactor is relatively complicated, and the added obstacles or baffles are relatively fixed and difficult to adapt to different phosphoric acid raw materials, which leads to poor separation effect for some phosphoric acid raw materials with excessive flow rate. Summary of the Invention

[0004] The present application provides a microchannel extraction reactor with a grid insert and its application to solve the following technical problem: how to improve the separation effect of metal impurities in phosphoric acid raw materials under different flow rate conditions.

[0005] In a first aspect, the present application provides a microchannel extraction reactor having a grid insert, the microchannel extraction reactor comprising:

[0006] microchannel panels;

[0007] An extraction unit comprising a holding tank, a linear microchannel, a front chamber, and a rear chamber, wherein the holding tank is disposed within the microchannel extraction reactor; the microchannel panel covers the surface of the holding tank to form an extraction space with the holding tank; the front chamber and the rear chamber are spaced apart within the holding tank along the length direction of the microchannel panel, a plurality of linear microchannels are uniformly distributed between the front chamber and the rear chamber along the width direction of the microchannel panel, and both ends of the linear microchannel are connected to the front chamber and the rear chamber, respectively;

[0008] a stainless steel filter screen assembly, comprising at least one slightly curved stainless steel filter screen, wherein the at least one slightly curved stainless steel filter screen is disposed in the receiving tank, with the raised end of the slightly curved stainless steel filter screen disposed toward the receiving tank, and the slightly curved stainless steel filter screen is disposed between the microchannel panel and the receiving tank;

[0009] At least two adjustment units, the two adjustment units are symmetrically arranged at both ends of the microchannel panel along the length direction of the microchannel panel; the adjustment unit includes a sliding support piece and an adjustment groove for accommodating the sliding support piece, and the adjustment groove runs through the side wall of the accommodating groove along the width direction; the sliding support piece is extended and retracted through the adjustment groove, and one end of the sliding support piece is fixedly connected to the slightly curved stainless steel filter screen, so that the degree of curvature of the slightly curved stainless steel filter screen can be adjusted through the sliding support piece.

[0010] Optionally, the length L1 of the slightly curved stainless steel filter screen and the length L2 of the receiving groove satisfy the relationship: L1:L2=(1.01-1.30):1.

[0011] Optionally, the distance d1 between the slightly curved stainless steel filter screen and the receiving groove and the distance d2 between the sliding support sheet and the receiving groove satisfy the relationship: d1:d2=(0.55-0.95):1; and / or

[0012] The distance d1 between the slightly curved stainless steel filter screen and the receiving tank is 0.55 mm to 0.95 mm.

[0013] Optionally, the pore size of the slightly curved stainless steel filter is 50 mesh to 80 mesh.

[0014] Optionally, the shortest distance d3 between the front chamber and the adjustment groove and the shortest distance d4 between the rear chamber and the adjustment groove satisfy the relationship: d3=d4;

[0015] The longest telescopic length L3 of the sliding support piece and the shortest distance d3 between the front chamber and the adjustment groove satisfy the relationship: L3=d3.

[0016] Optionally, a mixed liquid phase feed port is provided at the top of the front chamber, and a separated material discharge port is provided at the top of the rear chamber.

[0017] Optionally, an elastic gasket is provided on the surface of the microchannel panel, and the elastic gasket is provided between the microchannel panel and the accommodating groove.

[0018] In a second aspect, the present application provides a microchannel extraction reaction system having a grid insert, the microchannel extraction reaction system comprising:

[0019] A plurality of microchannel extraction reactors according to the first aspect connected in series, wherein the microchannel extraction reactors are provided with a heat-insulating jacket;

[0020] A raw material feeding unit, comprising a feeding pump and a three-way valve, wherein the discharge port of the feeding pump is connected to the feed port of the three-way valve, and the discharge port of the three-way valve is connected to the first microchannel extraction reactor;

[0021] A control unit includes a controller, a flow sensor, a stepper motor, a temperature sensor, a thermometer, and a constant temperature water bath circulation pump. The flow sensor is located between the three-way valve and the first microchannel extraction reactor. The stepper motor is connected to the sliding support plate of the microchannel extraction reactor. The temperature sensor is located in the insulation jacket of the middle microchannel extraction reactor. The controller is connected to the flow sensor, the stepper motor, the temperature sensor, and the constant temperature water bath circulation pump via electrical signals. The temperature sensor is connected to the thermometer via electrical signals.

[0022] A liquid separation unit, wherein the feed port of the liquid separation unit is connected to the microchannel extraction reactor at the end.

[0023] In a third aspect, the present application provides a method for purifying phosphoric acid by microchannel extraction, wherein the method is adapted to the microchannel extraction reaction system described in the second aspect; the method comprises:

[0024] According to the flow rate of phosphoric acid, the curvature of the slightly curved stainless steel filter in the microchannel extraction reaction system is adjusted to obtain an adjusted microchannel extraction reaction system;

[0025] Passing the extractant and the phosphoric acid into the adjusted microchannel extraction reaction system for extraction to obtain an extraction material;

[0026] Separating the extracted material to obtain purified phosphoric acid;

[0027] The extraction temperature is 35° C. to 45° C., and the extraction time is 22.5 s to 23.5 s.

[0028] Optionally, adjusting the curvature of the slightly curved stainless steel filter in the microchannel extraction reaction system according to the flow rate of phosphoric acid to obtain an adjusted microchannel extraction reaction system comprises the steps of:

[0029] When the flow rate of phosphoric acid is less than 1.0 m / s, the distance d1 between the slightly curved stainless steel filter and the holding tank in the microchannel extraction reaction system is adjusted to 0.85 mm to 0.95 mm;

[0030] When the flow rate of phosphoric acid is 1.0 m / s to 2.0 m / s, the distance d1 between the slightly curved stainless steel filter and the holding tank in the microchannel extraction reaction system is adjusted to 0.65 mm to 0.80 mm;

[0031] When the flow rate of phosphoric acid is greater than 2.0 m / s, the distance d1 between the slightly curved stainless steel filter and the holding tank in the microchannel extraction reaction system is adjusted to 0.55 mm to 0.60 mm.

[0032] The above technical solution provided by the embodiment of the present application has the following advantages compared with the prior art:

[0033] The present application provides a microchannel extraction reactor with a grid insert. The microchannel extraction reactor is based on a conventional parallel distributed Y-shaped multi-channel microextractor. A slightly curved stainless steel filter is disposed within a holding tank having linear microchannels. The slightly curved stainless steel filter disperses larger chunks of liquid-phase phosphoric acid into phosphoric acid droplets, thereby increasing the complexity of the flow state of the phosphoric acid solution in the liquid-phase fluid and increasing the specific surface area and phase interface of the phosphoric acid droplets. The more complex flow state of the phosphoric acid solution and the phosphoric acid droplets with larger specific surface area and phase interface improve the mass transfer efficiency of the phosphoric acid, thereby promoting sufficient mass transfer of phosphoric acid at the extraction phase interface, thereby improving the separation effect of metallic element impurities in the phosphoric acid raw material. In addition, the curvature of the slightly curved stainless steel filter is adjusted by an adjustment unit including a sliding support plate and an adjustment tank. The distance between the slightly curved stainless steel filter and the holding tank can be adjusted according to the different flow rates of phosphoric acid, further increasing the complexity of the flow state of the phosphoric acid solution in the liquid-phase fluid, thereby promoting sufficient mass transfer of phosphoric acid at the extraction phase interface, thereby improving the separation effect of metallic element impurities in the phosphoric acid raw material under different flow rate conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0035] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following is a brief introduction to the drawings required for use in the embodiments or the description of the prior art. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0036] Figure 1 A schematic diagram of the extraction unit structure of a microchannel extraction reactor with a grid insert provided in an embodiment of the present application;

[0037] Figure 2 A schematic cross-sectional view of a microchannel extraction reactor with a grid insert provided in an embodiment of the present application;

[0038] Figure 3 A schematic diagram of the logical structure of a microchannel extraction reaction system with a grid plug-in provided in an embodiment of the present application;

[0039] Figure 4 A schematic flow chart of a method for purifying phosphoric acid by microchannel extraction provided in an embodiment of the present application;

[0040] Figure 5 A detailed schematic diagram of a method for purifying phosphoric acid by microchannel extraction provided in an embodiment of the present application;

[0041] Figure 6 This is a graph showing the effect of increasing the number of microchannel extraction reactors in series from 1 to 4 on the extraction rate in the microchannel extraction reaction system provided in Example 1 of the present application;

[0042] Figure 7 This is a graph showing the effect of increasing the number of conventional extraction devices in series from 1 to 4 on the extraction rate provided in Comparative Example 1 of the present application;

[0043] Among them, 1-microchannel panel, 2-holding tank, 3-linear microchannel, 4-front chamber, 41-mixed liquid phase feed port, 5-back chamber, 51-separated material discharge port, 6-micro-curved stainless steel filter, 7-sliding support plate, 8-adjusting tank, 9-elastic gasket, 10-feeding pump, 11-three-way valve, 12-controller, 13-flow sensor, 14-stepping motor, 15-temperature sensor, 16-thermometer, 17-constant temperature water bath circulation pump, 18-liquid separation unit. DETAILED DESCRIPTION

[0044] To make the purpose, technical solutions, and advantages of the embodiments of this application more clear, the technical solutions in the embodiments of this application will be clearly and completely described below in conjunction with the drawings in the embodiments of this application. Obviously, the described embodiments are part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0045] Various embodiments of the present application may be presented in the form of a range; it should be understood that the description in the form of a range is only for convenience and brevity and should not be understood as a rigid limitation on the scope of the present application; therefore, the range description should be considered to have specifically disclosed all possible sub-ranges and single numerical values ​​within the range; for example, the range description from 1 to 6 should be considered to have specifically disclosed sub-ranges, such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., as well as single numbers within the range, such as 1, 2, 3, 4, 5 and 6, which apply regardless of the range; in addition, whenever a numerical range is indicated in this document, it is meant to include any cited number (fractional or integer) within the indicated range.

[0046] In this document, the terms including "including" and "comprising" mean "including but not limited to". Relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. "And / or" describes the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone; wherein A and B can be singular or plural. Unless otherwise specified, the various raw materials, reagents, instruments and equipment used in this document can be purchased on the market or prepared by existing methods.

[0047] Figure 1 The schematic diagram of the extraction unit structure of a microchannel extraction reactor with a grid insert provided in an embodiment of the present application is exemplarily shown;

[0048] Figure 2 A cross-sectional schematic diagram of a microchannel extraction reactor with a grid insert provided in an embodiment of the present application is exemplarily shown;

[0049] like Figure 1 and Figure 2 As shown, the embodiment of the present application provides a microchannel extraction reactor with a grid insert, the microchannel extraction reactor comprising:

[0050] Microchannel panel 1;

[0051] The extraction unit comprises a holding tank 2, a linear microchannel 3, a front chamber 4 and a rear chamber 5, wherein the holding tank 2 is provided in the microchannel extraction reactor; the microchannel panel 1 covers the surface of the holding tank 2 to form an extraction space with the holding tank 2; the front chamber 4 and the rear chamber 5 are respectively distributed in the holding tank 2 along the length direction of the microchannel panel 1, and the plurality of linear microchannels 3 are evenly distributed between the front chamber 4 and the rear chamber 5 along the width direction of the microchannel panel 1, and the two ends of the linear microchannel 3 are connected to the front chamber 4 and the rear chamber 5 respectively;

[0052] A stainless steel filter screen assembly, comprising at least one slightly curved stainless steel filter screen 6, wherein at least one slightly curved stainless steel filter screen 6 is disposed in the receiving tank 2, with the raised end of the slightly curved stainless steel filter screen 6 disposed toward the receiving tank 2, and the slightly curved stainless steel filter screen 6 is disposed between the microchannel panel 1 and the receiving tank 2;

[0053] At least two adjustment units, the two adjustment units are symmetrically arranged at both ends of the microchannel panel 1 along the length direction of the microchannel panel 1; the adjustment unit includes a sliding support piece 7 and an adjustment groove 8 for accommodating the sliding support piece 7, and the adjustment groove 8 runs through the side wall of the accommodating groove 2 along the width direction; the sliding support piece 7 is retracted and extended through the adjustment groove 8, and one end of the sliding support piece 7 is fixedly connected to the slightly curved stainless steel filter screen 6, so that the degree of bending of the slightly curved stainless steel filter screen 6 can be adjusted through the sliding support piece 7.

[0054] It should be noted that the fixed connection between the slightly curved stainless steel filter screen 6 and the sliding support plate 7 can be achieved by bending both ends of the slightly curved stainless steel filter screen 6 into fixed grooves and providing matching protrusions at both ends of the sliding support plate 7.

[0055] It should be noted that the sliding support piece 7 and the adjustment groove 8 can be sealed and waterproofed to avoid water leakage during the adjustment process.

[0056] It should be noted that the microchannel extraction reactor can be modified based on a parallel distributed Y-type multi-channel microextractor, and the single microextractor used in the parallel distributed Y-type multi-channel microextractor can be an extraction device as disclosed in CN202310860292.5; in the parallel distributed Y-type multi-channel microextractor, the multiple microchannels will reduce the cross-sectional size of the mixed water-oil two-phase to the size of the microchannel interface, thereby promoting the water-oil two-phase droplets to have a larger specific surface area and phase interface, so that the larger water-oil two-phase contact area is achieved. The Y-shaped structure forces the water-oil two-phase liquids to intersect at a certain angle, causing the continuous phase liquid velocity to be mostly deflected at the intersection, while the remaining part of the liquid still maintains the original velocity direction, while the droplets of the other part of the liquid undergo a certain degree of extrusion deformation or even rupture, resulting in further dispersion of the liquid droplets, thereby causing the water-oil droplets to collide more violently and increase the contact area of ​​the water-oil two-phase liquids; in addition, the linear part at the rear end of the Y-shaped structure can provide a stable environment for the contact of the water-oil two phases, allowing them to fully transfer mass at the phase interface.

[0057] It should be noted that the material of the microchannel panel 1 can be an organic glass shell. The organic glass shell has the characteristics of transparency and high hydrophilicity, and the flow state of the liquid phase in the microchannel extraction reactor can be observed.

[0058] In some optional embodiments, the length L1 of the slightly curved stainless steel filter screen 6 and the length L2 of the receiving tank 2 satisfy the relationship: L1:L2=(1.01-1.30):1;

[0059] In these embodiments, the length L1 of the slightly curved stainless steel filter screen 6 and the length L2 of the receiving tank 2 can satisfy the relationship: L1:L2=(1.01-1.30):1. This can ensure that the slightly curved stainless steel filter screen 6 has a sufficient degree of curvature. The slightly curved stainless steel filter screen 6 with a sufficient degree of curvature can disperse larger pieces of liquid phosphoric acid into phosphoric acid droplets, thereby increasing the complexity of the flow state of the phosphoric acid solution in the liquid phase fluid, as well as the specific surface area and phase interface of the phosphoric acid droplets, thereby improving the separation effect of metal element impurities in the phosphoric acid raw material under different flow rate conditions.

[0060] The length L1 of the slightly curved stainless steel filter screen 6 and the length L2 of the receiving tank 2 can satisfy the relationship: L1:L2=1.01:1, 1.02:1, 1.03:1, 1.04:1, 1.05:1, 1.10:1, 1.15:1, 1.20:1, 1.25:1 or 1.30:1.

[0061] In some optional embodiments, the distance d1 between the slightly curved stainless steel filter screen 6 and the receiving groove 2 and the distance d2 between the sliding support sheet 7 and the receiving groove 2 satisfy the relationship: d1:d2=(0.55-0.95):1; and / or

[0062] The distance d1 between the slightly curved stainless steel filter 6 and the receiving tank 2 is 0.55 mm to 0.95 mm;

[0063] In these embodiments, the distance d1 between the slightly curved stainless steel filter screen 6 and the receiving tank 2 and the distance d2 between the sliding support plate 7 and the receiving tank 2 can satisfy the relationship: d1:d2=(0.55-0.95):1, and the distance d1 between the slightly curved stainless steel filter screen 6 and the receiving tank 2 can be 0.55 mm to 0.95 mm, so that the distance between the slightly curved stainless steel filter screen 6 and the receiving tank 2 is within an adjustable range. The distance between the slightly curved stainless steel filter screen 6 and the receiving tank 2 can be adjusted according to the different flow rates of phosphoric acid to further increase the complexity of the flow state of the phosphoric acid solution in the liquid phase fluid, thereby promoting sufficient mass transfer of phosphoric acid at the extraction phase interface, thereby improving the separation effect of metal element impurities in the phosphoric acid raw material under different flow rate conditions.

[0064] The distance d1 between the slightly curved stainless steel filter screen 6 and the accommodating groove 2 and the distance d2 between the sliding support plate 7 and the accommodating groove 2 can satisfy the relationship: d1:d2=0.55:1, 0.60:1, 0.65:1, 0.70:1, 0.75:1, 0.80:1, 0.85:1, 0.90:1 or 0.95:1.

[0065] The distance d1 between the slightly curved stainless steel filter screen 6 and the receiving tank 2 can be 0.55 mm, 0.60 mm, 0.65 mm, 0.70 mm, 0.75 mm, 0.80 mm, 0.85 mm, 0.90 mm or 0.95 mm.

[0066] It should be noted that the phosphoric acid undergoes sufficient mass transfer at the extraction phase interface, which means that the metal impurities in the phosphoric acid are transferred from the aqueous phase of the phosphoric acid to the extractant to obtain a pure phosphoric acid product.

[0067] In some optional embodiments, the pore size of the slightly curved stainless steel filter 6 is 50 mesh to 80 mesh;

[0068] In these embodiments, the pore size of the slightly curved stainless steel filter 6 can be 50 mesh to 80 mesh, so that the slightly curved stainless steel filter 6 has a good pore size, thereby further increasing the complexity of the flow state of the phosphoric acid solution in the liquid phase fluid, thereby promoting sufficient mass transfer of phosphoric acid at the extraction phase interface, and improving the separation effect of metal element impurities in the phosphoric acid raw material under different flow rate conditions.

[0069] The pore size of the slightly curved stainless steel filter screen 6 can be 50 mesh, 55 mesh, 60 mesh, 65 mesh, 70 mesh, 75 mesh or 80 mesh.

[0070] In some optional embodiments, the shortest distance d3 between the front chamber 4 and the adjustment groove 8 and the shortest distance d4 between the rear chamber 5 and the adjustment groove 8 satisfy the relationship: d3=d4;

[0071] The longest telescopic length L3 of the sliding support piece 7 and the shortest distance d3 between the front chamber 4 and the adjustment slot 8 satisfy the relationship: L3=d3;

[0072] In these embodiments, the shortest distance d3 between the front chamber 4 and the adjustment groove 8 and the shortest distance d4 between the rear chamber 5 and the adjustment groove 8 can satisfy the relationship: d3=d4, and the telescopic length L3 of the sliding support plate 7 and the shortest distance d3 between the front chamber 4 and the adjustment groove 8 can satisfy the relationship: L3=d3, which can avoid the sliding support plate 7 from blocking the front chamber 4 and the rear chamber 5 during the telescopic process, thereby promoting sufficient mass transfer of phosphoric acid at the extraction phase interface, so as to improve the separation effect of metal element impurities in the phosphoric acid raw material under different flow rate conditions.

[0073] In some optional embodiments, a mixed liquid phase feed port 41 is provided at the top of the front chamber 4, and a separated material discharge port 51 is provided at the top of the rear chamber 5;

[0074] In these embodiments, a mixed liquid phase feed port 41 is provided at the top of the front chamber 4, and a separation material discharge port 51 is provided at the top of the rear chamber 5. According to the distribution positions of the front chamber 4 and the rear chamber 5, sufficient mass transfer of phosphoric acid at the extraction phase interface can be promoted to improve the separation effect of metal element impurities in the phosphoric acid raw material under different flow rate conditions.

[0075] In some optional embodiments, an elastic gasket 9 is provided on the surface of the microchannel panel 1, and the elastic gasket 9 is provided between the microchannel panel 1 and the receiving groove 2;

[0076] In these embodiments, an elastic gasket 9 may be provided on the surface of the microchannel panel 1, and the elastic gasket 9 is provided between the microchannel panel 1 and the receiving tank 2. The elastic gasket 9 seals the gap between the microchannel panel 1 and the receiving tank 2 to avoid leakage of the phosphoric acid raw material liquid and other unnecessary interference factors, thereby ensuring the stable operation of the microchannel extraction reactor.

[0077] Figure 3 The following is a schematic diagram showing the logical structure of a microchannel extraction reaction system with a grid plug-in provided in an embodiment of the present application;

[0078] Based on a general inventive concept, such as Figure 3 As shown, the embodiment of the present application provides a microchannel extraction reaction system with a grid plug-in, the microchannel extraction reaction system comprising:

[0079] A plurality of microchannel extraction reactors are connected in series, wherein the microchannel extraction reactor is provided with a heat-insulating jacket;

[0080] A raw material feeding unit includes a feeding pump 10 and a three-way valve 11, wherein the discharge port of the feeding pump 10 is connected to the feed port of the three-way valve 11, and the discharge port of the three-way valve 11 is connected to the first microchannel extraction reactor;

[0081] The control unit includes a controller 12, a flow sensor 13, a stepper motor 14, a temperature sensor 15, a thermometer 16, and a constant temperature water bath circulation pump 17. The flow sensor 13 is located between the three-way valve 11 and the first microchannel extraction reactor. The stepper motor 14 is connected to the sliding support plate 7 of the microchannel extraction reactor. The temperature sensor 15 is located in the insulation jacket of the middle microchannel extraction reactor. The controller 12 is connected to the flow sensor 13, the stepper motor 14, the temperature sensor 15, and the constant temperature water bath circulation pump 17 via electrical signals. The temperature sensor 15 is connected to the thermometer 16 via electrical signals.

[0082] The liquid separation unit 18 has a feed port connected to the microchannel extraction reactor at the end.

[0083] The microchannel extraction reaction system is implemented based on the above-mentioned microchannel extraction reactor. The specific structure of the microchannel extraction reactor can refer to the above-mentioned embodiment. Since the microchannel extraction reaction system adopts part or all of the technical solutions of the above-mentioned embodiment, it has at least all the beneficial effects brought about by the technical solutions of the above-mentioned embodiment, which will not be described one by one here.

[0084] It should be noted that the controller 12 may be an S7-200 SMART PLC controller 12 ; the flow sensor 13 may be a Helen SEN-HZ06W flow sensor 13 ; and the temperature sensor 15 may be a WRNT-10 stainless steel K-type temperature sensor 15 .

[0085] Figure 4 A schematic flow chart of a method for purifying phosphoric acid by microchannel extraction provided in an embodiment of the present application is shown as an example;

[0086] Based on a general inventive concept, such as Figure 4 As shown, the embodiment of the present application provides a method for purifying phosphoric acid by microchannel extraction, and the method is adapted to the microchannel extraction reaction system; the method comprises:

[0087] S1 according to the flow rate of phosphoric acid, the microchannel extraction reaction system within the slightly curved stainless steel filter 6 is adjusted to obtain an adjusted microchannel extraction reaction system;

[0088] S2. The extractant and the phosphoric acid are introduced into the adjusted microchannel extraction reaction system to obtain an extract material;

[0089] S3. The extracted material is separated to obtain purified phosphoric acid;

[0090] The extraction temperature is 35° C. to 45° C., and the extraction time is 22.5 s to 23.5 s.

[0091] This method is implemented based on the above-mentioned microchannel extraction reaction system. The specific structure of the microchannel extraction reaction system can refer to the above-mentioned embodiment. Since this method adopts part or all of the technical solutions of the above-mentioned embodiment, it has at least all the beneficial effects brought about by the technical solutions of the above-mentioned embodiment, which will not be described one by one here.

[0092] It should be noted that the extraction temperature can be 35° C. to 45° C., and the extraction time can be 22.5 s to 23.5 s. The microchannel extraction reaction system can enable the extractant to effectively extract impurities in the phosphoric acid raw material.

[0093] The temperature of the extraction can be 35°C, 36°C, 37°C, 38°C, 39°C, 40°C, 41°C, 42°C, 43°C, 44°C or 45°C.

[0094] The extraction time may be 22.5s, 22.6s, 22.7s, 22.8s, 22.9s, 23.0s, 23.1s, 23.2s, 23.3s, 23.4s or 23.5s.

[0095] It should be noted that the introduction flow rate of the extractant and the phosphoric acid can be 1:1.

[0096] It should be noted that the extractant can be a mixed solution of extractant P204 and kerosene, and the mass concentration of the extractant P204 can be 50%.

[0097] Figure 5 A detailed flow chart of a method for purifying phosphoric acid by microchannel extraction provided in an embodiment of the present application is exemplarily shown;

[0098] In some optional embodiments, adjusting the curvature of the slightly curved stainless steel filter 6 in the microchannel extraction reaction system according to the flow rate of phosphoric acid to obtain an adjusted microchannel extraction reaction system comprises the steps of:

[0099] S101. When the flow rate of phosphoric acid is less than 1.0 m / s, the distance d1 between the micro-curved stainless steel filter 6 and the receiving tank 2 in the microchannel extraction reaction system is adjusted to 0.85 mm to 0.95 mm;

[0100] S102. When the flow rate of phosphoric acid is 1.0 m / s to 2.0 m / s, the distance d1 between the micro-curved stainless steel filter 6 and the receiving tank 2 in the microchannel extraction reaction system is adjusted to 0.65 mm to 0.80 mm;

[0101] S103. In the case of phosphoric acid flow rate > 2.0 m / s, adjust the distance d1 between the micro-curved stainless steel filter 6 and the receiving tank 2 in the microchannel extraction reaction system to 0.55 mm ~ 0.60 mm;

[0102] In these embodiments, the distance d1 between the slightly curved stainless steel filter 6 and the holding tank 2 in the microchannel extraction reaction system is adjusted at flow rates of 1.0 m / s and 2.0 m / s, respectively. The width of the gap between the slightly curved stainless steel filter 6 and the holding tank 2 can be adjusted according to the actual flow rate of the phosphoric acid raw material to further increase the complexity of the flow state of the phosphoric acid solution in the liquid phase fluid, thereby promoting sufficient mass transfer of phosphoric acid at the extraction phase interface, thereby improving the separation effect of metal element impurities in the phosphoric acid raw material under different flow rate conditions.

[0103] It should be noted that, when the flow rate of phosphoric acid is less than 1.0 m / s, the distance d1 between the slightly curved stainless steel filter 6 and the holding tank 2 in the microchannel extraction reaction system can be adjusted to 0.85 mm, 0.86 mm, 0.87 mm, 0.88 mm, 0.89 mm, 0.90 mm, 0.91 mm, 0.92 mm, 0.93 mm, 0.94 mm or 0.95 mm; when the flow rate of phosphoric acid is 1.0 m / s to 2.0 m / s, the distance d1 between the slightly curved stainless steel filter 6 and the holding tank 2 in the microchannel extraction reaction system can be adjusted to 0.65 mm. , 0.66mm, 0.67mm, 0.68mm, 0.69mm, 0.70mm, 0.71mm, 0.72mm, 0.73mm, 0.74mm, 0.75mm, 0.76mm, 0.77mm, 0.78mm, 0.79mm or 0.80mm; when the flow rate of phosphoric acid is greater than 2.0m / s, the distance d1 between the slightly curved stainless steel filter 6 and the containing tank 2 in the microchannel extraction reaction system can be adjusted to 0.55mm, 0.56mm, 0.57mm, 0.58mm, 0.59mm or 0.60mm.

[0104] The present application is further described below with reference to specific examples. Experimental methods in the following examples where specific conditions are not specified are generally measured in accordance with national / industry standards. If there are no corresponding national / industry standards, the methods are carried out in accordance with commonly used international standards, conventional conditions, or conditions recommended by the manufacturer. Example 1

[0105] like Figure 1 and Figure 2 As shown, a microchannel extraction reactor with a grid insert comprises:

[0106] Microchannel panel 1;

[0107] The extraction unit comprises a holding tank 2, a linear microchannel 3, a front chamber 4 and a rear chamber 5, wherein the holding tank 2 is provided in a microchannel extraction reactor; a microchannel panel 1 covers the surface of the holding tank 2 to form an extraction space with the holding tank 2; the front chamber 4 and the rear chamber 5 are respectively spaced apart along the length direction of the microchannel panel 1 in the holding tank 2, and a plurality of linear microchannels 3 are evenly distributed between the front chamber 4 and the rear chamber 5 along the width direction of the microchannel panel 1, and the two ends of the linear microchannel 3 are respectively connected to the front chamber 4 and the rear chamber 5;

[0108] A stainless steel filter screen assembly, comprising a slightly curved stainless steel filter screen 6, wherein at least one slightly curved stainless steel filter screen 6 is disposed in the receiving tank 2, with the raised end of the slightly curved stainless steel filter screen 6 disposed toward the receiving tank 2, and the slightly curved stainless steel filter screen 6 is disposed between the microchannel panel 1 and the receiving tank 2;

[0109] Two adjustment units are symmetrically arranged at both ends of the microchannel panel 1 along the length direction of the microchannel panel 1; the adjustment unit includes a sliding support piece 7 and an adjustment groove 8 for accommodating the sliding support piece 7, and the adjustment groove 8 runs through the side wall of the accommodating groove 2 along the width direction; the sliding support piece 7 is retracted and retracted through the adjustment groove 8, and one end of the sliding support piece 7 is fixedly connected to the slightly curved stainless steel filter screen 6, so that the degree of bending of the slightly curved stainless steel filter screen 6 can be adjusted through the sliding support piece 7.

[0110] The length L1 of the slightly curved stainless steel filter screen 6 and the length L2 of the receiving tank 2 satisfy the relationship: L1:L2=1.20:1.

[0111] The distance d1 between the slightly curved stainless steel filter screen 6 and the receiving groove 2 and the distance d2 between the sliding support piece 7 and the receiving groove 2 satisfy the relationship: d1:d2=0.70:1.

[0112] The distance d1 between the slightly curved stainless steel filter screen 6 and the containing tank 2 is 0.70 mm.

[0113] The pore size of the slightly curved stainless steel filter screen 6 is 50 meshes.

[0114] The shortest distance d3 between the front chamber 4 and the adjustment groove 8 and the shortest distance d4 between the rear chamber 5 and the adjustment groove 8 satisfy the relationship: d3=d4;

[0115] The longest telescopic length L3 of the sliding support piece 7 and the shortest distance d3 between the front chamber 4 and the adjustment groove 8 satisfy the relationship: L3=d3.

[0116] A mixed liquid phase feed port 41 is provided at the top of the front chamber 4 , and a separated material discharge port 51 is provided at the top of the rear chamber 5 .

[0117] An elastic gasket 9 is provided on the surface of the micro-channel panel 1 , and the elastic gasket 9 is provided between the micro-channel panel 1 and the receiving groove 2 .

[0118] like Figure 3 As shown, a microchannel extraction reaction system with a grid insert comprises:

[0119] Three microchannel extraction reactors connected in series, each microchannel extraction reactor being provided with a heat-insulating jacket;

[0120] The raw material feeding unit includes a feeding pump 10 and a three-way valve 11. The discharge port of the feeding pump 10 is connected to the feed port of the three-way valve 11, and the discharge port of the three-way valve 11 is connected to the first microchannel extraction reactor;

[0121] The control unit includes a controller 12, a flow sensor 13, a stepper motor 14, a temperature sensor 15, a thermometer 16, and a constant temperature water bath circulation pump 17. The flow sensor 13 is located between the three-way valve 11 and the first microchannel extraction reactor. The stepper motor 14 is connected to the sliding support plate 7 of the microchannel extraction reactor. The temperature sensor 15 is located in the insulation jacket of the middle microchannel extraction reactor. The controller 12 is connected to the flow sensor 13, the stepper motor 14, the temperature sensor 15, and the constant temperature water bath circulation pump 17 via electrical signals. The temperature sensor 15 is connected to the thermometer 16 via electrical signals.

[0122] The liquid separation unit 18 has a feed port connected to the final microchannel extraction reactor.

[0123] The extractant P204 was added to kerosene to prepare an organic phase with a mass fraction of 50%. Then, a certain amount of phosphoric acid solution and solid zinc sulfate heptahydrate were added to deionized water to prepare a solution with a zinc ion content of 50 ppm and a phosphoric acid content of 25% as aqueous phosphoric acid.

[0124] like Figure 4 As shown, a method for purifying phosphoric acid by microchannel extraction comprises:

[0125] S102. When the flow rate of phosphoric acid is 1.5 m / s, the distance d1 between the slightly curved stainless steel filter 6 and the receiving tank 2 in the microchannel extraction reaction system is adjusted to 0.70 mm to obtain the adjusted microchannel extraction reaction system;

[0126] S2. The extractant and phosphoric acid are introduced into the adjusted microchannel extraction reaction system to obtain an extract material;

[0127] S3. The extracted material is separated to obtain purified phosphoric acid;

[0128] The extraction temperature was 40° C., and the extraction time was 23.11 s.

[0129] Example 2

[0130] Based on the content disclosed in Example 1, the following modifications are further made:

[0131] The length L1 of the slightly curved stainless steel filter screen 6 and the length L2 of the receiving tank 2 satisfy the relationship: L1:L2=1.18:1.

[0132] The distance d1 between the slightly curved stainless steel filter screen 6 and the receiving groove 2 and the distance d2 between the sliding support sheet 7 and the receiving groove 8 satisfy the relationship: d1:d2=0.65:1.

[0133] The distance d1 between the slightly curved stainless steel filter screen 6 and the receiving tank 2 is 0.65 mm.

[0134] The pore size of the slightly curved stainless steel filter is 70 mesh.

[0135] Example 3

[0136] Based on the content disclosed in Example 1, the following modifications are further made:

[0137] The length L1 of the slightly curved stainless steel filter screen 6 and the length L2 of the receiving tank 2 satisfy the relationship: L1:L2=1.23:1.

[0138] The distance d1 between the slightly curved stainless steel filter screen 6 and the receiving groove 2 and the distance d2 between the sliding support piece 7 and the receiving portion 28 satisfy the relationship: d1:d2=0.80:1.

[0139] The distance d1 between the slightly curved stainless steel filter screen 6 and the receiving tank 2 is 0.80 mm.

[0140] The pore size of the slightly curved stainless steel filter screen 6 is 80 meshes.

[0141] Example 4

[0142] Based on the content disclosed in Example 1, the following modifications are further made:

[0143] S101. When the flow rate of phosphoric acid is 0.5 m / s, the distance d1 between the slightly curved stainless steel filter 6 and the containing tank 2 in the microchannel extraction reaction system is adjusted to 0.90 mm to obtain the adjusted microchannel extraction reaction system.

[0144] The length L1 of the slightly curved stainless steel filter screen 6 and the length L2 of the receiving tank 2 satisfy the relationship: L1:L2=1.02:1.

[0145] The distance d1 between the slightly curved stainless steel filter screen 6 and the receiving groove 2 and the distance d2 between the sliding support piece 7 and the receiving groove 2 satisfy the relationship: d1:d2=0.90:1.

[0146] Example 5

[0147] Based on the content disclosed in Example 1, the following modifications are further made:

[0148] S103. When the flow rate of phosphoric acid is 3.0 m / s, the distance d1 between the slightly curved stainless steel filter 6 and the containing tank 2 in the microchannel extraction reaction system is adjusted to 0.55 mm to obtain the adjusted microchannel extraction reaction system.

[0149] The length L1 of the slightly curved stainless steel filter screen 6 and the length L2 of the receiving tank 2 satisfy the relationship: L1:L2=1.29:1.

[0150] The distance d1 between the slightly curved stainless steel filter screen 6 and the receiving groove 2 and the distance d2 between the sliding support piece 7 and the receiving groove 2 satisfy the relationship: d1:d2=0.55:1.

[0151] Example 6

[0152] Based on the content disclosed in Example 1, the following modifications are further made:

[0153] The extraction temperature was 35°C, and the extraction time was 23.5s.

[0154] Example 7

[0155] Based on the content disclosed in Example 1, the following modifications are further made:

[0156] The extraction temperature was 45°C and the extraction time was 22.5s.

[0157] Comparative Example 1

[0158] Based on the content disclosed in Example 1, the following modifications are further made:

[0159] Without using microchannel extraction reaction system, the specific process is:

[0160] The aqueous phase and the organic phase were placed in a conical flask and placed in a constant temperature water bath shaker at 40°C for 24 seconds, and then a four-stage extraction experiment was performed using a separatory funnel.

[0161] Comparative Example 2

[0162] Based on the content disclosed in Example 1, the following modifications are further made:

[0163] The length L1 of the slightly curved stainless steel filter screen 6 and the length L2 of the receiving tank 2 satisfy the relationship: L1:L2=1.29:1.

[0164] The distance d1 between the slightly curved stainless steel filter screen 6 and the receiving groove 2 and the distance d2 between the sliding support piece 7 and the receiving groove 2 satisfy the relationship: d1:d2=0.55:1.

[0165] The distance d1 between the slightly curved stainless steel filter screen 6 and the receiving tank 2 is 0.55 mm.

[0166] Comparative Example 3

[0167] Based on the content disclosed in Example 1, the following modifications are further made:

[0168] The length L1 of the slightly curved stainless steel filter screen 6 and the length L2 of the receiving tank 2 satisfy the relationship: L1:L2=1.02:1.

[0169] The distance d1 between the slightly curved stainless steel filter screen 6 and the receiving groove 2 and the distance d2 between the sliding support piece 7 and the receiving groove 2 satisfy the relationship: d1:d2=0.90:1.

[0170] The distance d1 between the slightly curved stainless steel filter screen 6 and the receiving tank 2 is 0.90 mm.

[0171] Related experiments and effect data:

[0172] Based on the microchannel extraction reactor disclosed in Example 1, the number of microchannel extraction reactors in series in the microchannel extraction reaction system was increased step by step from 1 to 4. In addition, based on the traditional extraction disclosed in Comparative Example 1, the number of separatory funnels was increased step by step from 1 to 4. The final results are as follows: Figure 6 and Figure 7 shown.

[0173] The purified phosphoric acid obtained in each embodiment and comparative example and the separated aqueous phase were collected separately, and the zinc ion concentration of the separated aqueous phase was measured using an atomic absorption spectrometer. The extraction rate of the entire method or system was determined based on the change in the zinc ion concentration, where the extraction rate is the ratio of the zinc ion concentration in the separated aqueous phase to the zinc ion concentration in the phosphoric acid raw material solution. The results are shown in Table 1.

[0174] Table 1 Extraction rates of purified phosphoric acid and aqueous phase obtained in various examples and comparative examples

[0175]

[0176] From Table 1 and Figure 6 and Figure 7 It can be seen that the embodiment of the present application provides a microchannel extraction reactor with a grid plug-in. The microchannel extraction reactor is based on the traditional parallel distributed Y-type multi-channel micro-extractor. A slightly curved stainless steel filter screen 6 is arranged in a holding tank with a linear microchannel, and an adjustment unit including a sliding support plate 7 and an adjustment groove 8 adjusts the curvature of the slightly curved stainless steel filter screen 6, which can promote sufficient mass transfer of phosphoric acid at the extraction phase interface to improve the separation effect of metal element impurities in the phosphoric acid raw material under different flow rate conditions.

[0177] In addition, an embodiment of the present application provides a microchannel extraction reactor with a grid plug-in. The microchannel extraction reactor has a simple structure and each component can be disassembled and assembled, thereby facilitating operations such as replacement, maintenance, and cleaning of each component.

[0178] In addition, an embodiment of the present application provides a microchannel extraction reaction system with a grid insert. Under the same operating temperature conditions, the microchannel extraction reaction system can achieve the same extraction efficiency at a lower oil-water ratio (volume ratio of 1:1) and in a shorter extraction time than the extraction system used in traditional extraction methods. This can significantly reduce the extraction time and save the amount of extractant used, thereby significantly improving production efficiency and reducing production costs.

[0179] In addition, an embodiment of the present application provides a microchannel extraction reaction system with a grid plug-in. This microchannel extraction reaction system can reduce the concentration of impurity metal zinc ions in strong acid from 50 ppm to about 25 ppm in a strong acid environment, has a good extraction enhancement effect, and has important application significance in the deep purification of chemical impurities in strong acid.

[0180] In addition, an embodiment of the present application provides a microchannel extraction reaction system with a grid plug-in. The structured components of the microchannel extraction reaction system lower its manufacturing cost and are easier to integrate with other equipment.

[0181] The foregoing is merely a list of specific embodiments of the present application, intended to enable those skilled in the art to understand or implement the present application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application is not limited to the embodiments shown herein, but rather is intended to conform to the broadest scope consistent with the principles and novel features claimed herein.

Claims

1. A microchannel extraction reactor with a grid insert, the microchannel extraction reactor comprising: Microchannel Panel (1); extraction unit; The invention comprises a containing tank (2), a linear microchannel (3), a front chamber (4) and a back chamber (5), wherein the containing tank (2) is arranged in the microchannel extraction reactor; the microchannel panel (1) covers the surface of the containing tank (2) to form an extraction space with the containing tank (2); the front chamber (4) and the back chamber (5) are respectively distributed in the containing tank (2) along the length direction of the microchannel panel (1); a plurality of linear microchannels (3) are evenly distributed between the front chamber (4) and the back chamber (5) along the width direction of the microchannel panel (1), and the two ends of the linear microchannel (3) are respectively connected to the front chamber (4) and the back chamber (5); A stainless steel filter screen assembly, comprising at least one micro-curved stainless steel filter screen (6), wherein at least one micro-curved stainless steel filter screen (6) is disposed in the receiving tank (2), and a raised end of the micro-curved stainless steel filter screen (6) is disposed toward the receiving tank (2), and the micro-curved stainless steel filter screen (6) is disposed between the micro-channel panel (1) and the receiving tank (2); At least two adjustment units are provided, the two adjustment units being symmetrically arranged at both ends of the microchannel panel (1) along the length direction of the microchannel panel (1); the adjustment units comprising a sliding support sheet (7) and an adjustment groove (8) for accommodating the sliding support sheet (7), the adjustment groove (8) penetrating the side wall of the accommodating groove (2) along the width direction; the sliding support sheet (7) is extended and retracted through the adjustment groove (8), and one end of the sliding support sheet (7) is fixedly connected to the micro-curved stainless steel filter screen (6), so that the degree of curvature of the micro-curved stainless steel filter screen (6) is adjusted by the sliding support sheet (7).

2. The microchannel extraction reactor according to claim 1, wherein the length L1 of the micro-curved stainless steel filter (6) and the length L2 of the receiving tank (2) satisfy the relationship: L1:L2=(1.01-1.30):

1.

3. The microchannel extraction reactor according to claim 1 or 2, wherein the distance d1 between the slightly curved stainless steel filter screen (6) and the receiving tank (2) and the distance d2 between the sliding support sheet (7) and the receiving tank (2) satisfy the relationship: d1:d2=(0.55-0.95):1; and / or The distance d1 between the slightly curved stainless steel filter screen (6) and the containing tank (2) is 0.55 mm to 0.95 mm.

4. The microchannel extraction reactor according to claim 1, wherein the pore size of the micro-curved stainless steel filter (6) is 50 mesh to 80 mesh.

5. The microchannel extraction reactor according to claim 1, wherein the shortest distance d3 between the front chamber (4) and the adjustment tank (8) and the shortest distance d4 between the rear chamber (5) and the adjustment tank (8) satisfy the relationship: d3=d4; The longest telescopic length L3 of the sliding support plate (7) and the shortest distance d3 between the front chamber (4) and the adjustment groove (8) satisfy the relationship: L3=d3.

6. The microchannel extraction reactor according to claim 1, wherein a mixed liquid phase feed port (41) is provided at the top of the front chamber (4), and a separated material discharge port (51) is provided at the top of the rear chamber (5).

7. The microchannel extraction reactor according to claim 1, wherein an elastic gasket (9) is provided on the surface of the microchannel panel (1), and the elastic gasket (9) is provided between the microchannel panel (1) and the containing tank (2).

8. A microchannel extraction reaction system with a grid insert, the microchannel extraction reaction system comprising: A plurality of microchannel extraction reactors according to any one of claims 1 to 7 connected in series, wherein the microchannel extraction reactor is provided with a heat-insulating jacket; A raw material feeding unit comprises a feeding pump (10) and a three-way valve (11), wherein the discharge port of the feeding pump (10) is connected to the feed port of the three-way valve (11), and the discharge port of the three-way valve (11) is connected to the first microchannel extraction reactor; A control unit includes a controller (12), a flow sensor (13), a stepper motor (14), a temperature sensor (15), a thermometer (16) and a constant temperature water bath circulation pump (17), wherein the flow sensor (13) is arranged between the three-way valve (11) and the first microchannel extraction reactor, and the stepper motor (14) is connected to the sliding support plate (7) of the microchannel extraction reactor; the temperature sensor (15) is arranged in the insulation jacket of the middle microchannel extraction reactor, and the controller (12) is connected to the flow sensor (13), the stepper motor (14), the temperature sensor (15) and the constant temperature water bath circulation pump (17) respectively through electrical signals; the temperature sensor (15) is connected to the thermometer (16) through electrical signals; A liquid separation unit (18), wherein the feed port of the liquid separation unit (18) is connected to the microchannel extraction reactor at the end.

9. A method for purifying phosphoric acid by microchannel extraction, the method being adapted to the microchannel extraction reaction system of claim 8; the method comprising: According to the flow rate of phosphoric acid, the curvature of the slightly curved stainless steel filter (6) in the microchannel extraction reaction system is adjusted to obtain an adjusted microchannel extraction reaction system; Passing the extractant and the phosphoric acid into the adjusted microchannel extraction reaction system for extraction to obtain an extraction material; Separating the extracted material to obtain purified phosphoric acid; The extraction temperature is 35° C. to 45° C., and the extraction time is 22.5 s to 23.5 s.

10. The method according to claim 9, wherein the curvature of the slightly curved stainless steel filter (6) in the microchannel extraction reaction system is adjusted according to the flow rate of phosphoric acid to obtain the adjusted microchannel extraction reaction system, comprising the steps of: When the flow rate of phosphoric acid is less than 1.0 m / s, the distance d1 between the slightly curved stainless steel filter (6) and the holding tank (2) in the microchannel extraction reaction system is adjusted to 0.85 mm to 0.95 mm; When the flow rate of phosphoric acid is 1.0 m / s to 2.0 m / s, the distance d1 between the micro-curved stainless steel filter (6) and the holding tank (2) in the microchannel extraction reaction system is adjusted to 0.65 mm to 0.80 mm; When the flow rate of phosphoric acid is greater than 2.0 m / s, the distance d1 between the slightly curved stainless steel filter (6) and the containing tank (2) in the microchannel extraction reaction system is adjusted to 0.55 mm to 0.60 mm.

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