Device and method for efficiently preparing CeO2 by using hydrothermal method

Abstract

The application discloses a device for efficiently preparing by a hydrothermal method, which comprises a hydrothermal box, a vacuum heating box arranged on the upper end surface of the hydrothermal box, and a vacuum pump connected to the vacuum heating box; a partition layer plate horizontally fixed at the middle position in the interior of the vacuum heating box, which divides the interior of the vacuum heating box into a main reaction bin and a sub-reaction bin; multiple placing grooves arranged in an array and evenly distributed on the upper end surface of the partition layer plate; a reaction kettle corresponding to each spring base, wherein multiple reaction kettles store prepared mixed solutions; a circulating liquid pumping unit arranged above the interior of the vacuum heating box; and a temperature controller installed in the sub-reaction bin, wherein the liquid pumping end and the liquid discharging end of the circulating liquid pumping unit are communicated with the temperature controller.

Description

Technical Field

[0001] The present invention belongs to the technical field of rare earth material preparation, and in particular relates to a device and method for efficiently preparing CeO2 by a hydrothermal method. Background Art

[0002] In recent years, with the rapid development and widespread application of new rare earth materials, experimental studies have found that ultrafine powder cerium dioxide has new and excellent properties, and nano-cerium dioxide as a coating and additive can improve the oxidation resistance, thermal corrosion, water corrosion and sulfidation properties of high-temperature alloys and stainless steel, and can also be used as a nucleant for ductile iron; the current experimental method for preparing cerium dioxide is mainly the hydrothermal method, that is, in a high-pressure autoclave, by controlling the temperature and pressure, the cerium salt is hydrolyzed to generate cerium dioxide, and in the hydrothermal preparation, a single experiment can only heat and pressurize the solution in one reactor. If the hydrothermal box heats and reacts the solutions in multiple reactors at the same time, due to certain differences between each solution, the use of a unified heating and pressurizing method is likely to lead to differences in reaction rate and product properties; and each reactor is located at a different position in the hydrothermal box, it is difficult to ensure that the heating and pressurizing conditions of each reactor are completely consistent, resulting in different reaction conditions.

[0003] Therefore, it is necessary to provide a device and method for efficiently preparing CeO2 using a hydrothermal method to solve the problems raised in the above background technology. Summary of the Invention

[0004] To achieve the above object, the present invention provides the following technical solution: a device for efficiently preparing CeO2 using a hydrothermal method, comprising:

[0005] The water heating box has a vacuum heating box on its upper end surface, and the vacuum heating box is externally connected to a vacuum pump for vacuuming the interior thereof;

[0006] A partition plate is fixed horizontally in the middle of the vacuum heating box, and the partition plate divides the interior of the vacuum heating box into a main reaction chamber and a secondary reaction chamber, with the main reaction chamber located above the secondary reaction chamber;

[0007] A plurality of placement slots are arranged and evenly distributed on the upper end surface of the separation layer, and a spring base is installed in each placement slot;

[0008] Reactors, arranged corresponding to the spring bases, wherein the plurality of reactors contain pre-prepared mixed solutions;

[0009] Circulating liquid pumping units are arranged above the interior of the vacuum heating box, each of the circulating liquid pumping units is arranged corresponding to the placement slot, and the circulating liquid pumping units are vertically facing the reactor and are detachably threaded and sealed to the reactor;

[0010] A temperature controller is installed in the secondary reaction chamber, and the liquid extraction end and the liquid discharge end of the circulating liquid extraction unit are both connected to the temperature controller; after the solution in the reactor is heated and reacted in the main reaction chamber and the first stage of heating is completed, the circulating liquid extraction unit performs liquid extraction circulation, and the temperature controller dynamically adjusts the heating temperature according to the current temperature of the mixed solution in the reactor, thereby providing heating assistance, so that the mixed solution in each reactor reaches the corresponding expected reaction temperature, so that the mixed solution in the subsequent reactor can be completely reacted in the main reaction chamber.

[0011] Furthermore, preferably, each of the temperature controllers is provided with a temperature sensor, and the temperature sensor is used to monitor the current temperature of the mixed solution in real time.

[0012] Furthermore, preferably, the circulating pumping unit includes:

[0013] A kettle cover is threadedly connected to the reactor, a connecting rod is vertically fixed above the interior of the vacuum heating box, and the lower end of the connecting rod is fixed to the kettle cover;

[0014] A drain seat is fixed to the upper end of the connecting rod, and two drain channels are symmetrically provided on the drain seat, and each drain channel is connected to a drain pipe;

[0015] A liquid extraction pipe is vertically connected and fixed on the reactor cover, and the lower end of the liquid extraction pipe is deeply inserted into the reactor;

[0016] A rotating tube connected to the upper end of the liquid extraction tube;

[0017] The pump chamber is arranged above the drainage seat, and a liquid guide tube is vertically connected to the bottom of the pump chamber and is connected to the drainage seat through the liquid guide tube; the other end of the rotating tube is horizontally connected to the side wall of the pump chamber;

[0018] An impeller is rotatably connected in the pump chamber, and a drive shaft is provided above the pump chamber, one end of the drive shaft is connected to the impeller;

[0019] A reflux pipe is provided on one side of the pump compartment, one end of the reflux pipe is connected to the temperature controller, and the other end thereof is vertically connected to the side wall of the liquid extraction pipe;

[0020] The inner tube is co-centeredly arranged in the liquid extraction tube, and the return tube is sealed and connected to the inner tube.

[0021] Furthermore, preferably, the driving shaft drives the impeller to rotate, pumping the mixed solution in the reactor into the pump chamber through the liquid suction pipe, and diverting it into the temperature controller through each discharge pipe. The mixed solution discharged from the temperature controller enters the reflux pipe and finally flows into the bottom of the reactor through the inner tube.

[0022] Furthermore, preferably, the lower end of the inner tube extends into the bottom of the reactor, and the distance between the lower end of the inner tube and the inner wall of the bottom of the reactor is no more than 2 cm.

[0023] Furthermore, preferably, the temperature controller includes:

[0024] A cylinder body, a temperature regulator is installed inside the cylinder body, an annular cavity is provided on the side wall of the cylinder body, two partitions are vertically symmetrically arranged in the annular cavity, the partitions divide the annular cavity into two flow channels, and each drainage pipe in the circulating pumping unit is connected to the flow channel;

[0025] A plurality of liner plates are evenly arranged, each of the liner plates being vertically fixed in the flow channel;

[0026] A guide bar is provided corresponding to each of the lining plates, one end of the guide bar is connected to the lining plate, a bottom support plate is provided in the flow channel, the cross section of the bottom support plate is an arc-shaped structure, and the other end of the guide bar is fixed to the bottom support plate;

[0027] An upper flow port is provided on the side wall of each of the lining plates at an even-numbered position; and a lower flow port is provided on the side wall of each of the guide bars at an odd-numbered position;

[0028] The external pipes are vertically connected to the outside of each of the flow channels. A horizontal pipe is connected between the external pipes, and the return pipe in the circulating pumping unit is connected to the horizontal pipe.

[0029] Further, as a preference, the guide bar is slidably connected to the liner, and the bottom support plate slides along the axial direction of the cylinder, an outer ring frame is coaxially provided below the cylinder, a support rod is vertically connected to the outer ring frame, and the upper end of the support rod is connected to the bottom support plate;

[0030] A pneumatic telescopic rod is fixed on the cylinder, and the telescopic end of the pneumatic telescopic rod is connected to the outer ring frame.

[0031] Furthermore, preferably, the outer ring frame adjusts the effective flow area in the flow channel by sliding up and down, so that the mixed solution is heat-conducted and temperature-controlled in the temperature controller along a flow trajectory of corresponding length.

[0032] Furthermore, as a preferred method, a method for efficiently preparing CeO2 using a hydrothermal method is provided.

[0033] It includes the following steps:

[0034] S1. Selecting cerium nitrate hexahydrate, sodium hydroxide and deionized water as the relevant raw materials for preparation, and dissolving the raw materials, wherein the cerium nitrate hexahydrate is dissolved in a predetermined amount of deionized water and completely stirred and dissolved by a magnetic stirrer to form a transparent solution, while sodium hydroxide is dissolved in a predetermined amount of deionized water to form a sodium hydroxide solution; then slowly adding the sodium hydroxide solution to the transparent solution while stirring, and adjusting the pH value of the solution;

[0035] S2. The solution is divided into multiple portions and transferred to each reactor, and then the reactors are spirally mounted under the reactor cover in the circulating liquid extraction unit. At this time, the liquid extraction tube and the inner tube can be immersed in the mixed solution in the reactor, the door of the vacuum heating box is closed and vacuum heating is performed;

[0036] S3. Maintain the reaction temperature of the vacuum heating box at 120°C for a predetermined period of 4-6 hours. Start the circulating pumping unit to allow the mixed solution in each reactor to enter the temperature controller. The temperature sensor in each temperature controller obtains the current temperature of the mixed solution. The temperature controller then adjusts the heating power based on the respective temperature data to ensure that the temperature of the solution in each reactor reaches the expected reaction temperature for the second stage.

[0037] S4. The mixed solution was finally heated to 180°C in the main reaction chamber for 12 hours. After the reaction was completed, the heating device of the vacuum heating box was turned off, and the reactor was removed from the vacuum heating box and naturally cooled to room temperature.

[0038] S5. The reaction products are separated, washed, and completely dried, and finally calcined in a combustion furnace.

[0039] Compared with the prior art, the present invention has the following beneficial effects:

[0040] The present invention can simultaneously heat and pressurize the mixed solutions in multiple reactors, thereby improving the efficiency of CeO2 preparation. The main circulating liquid pumping unit can circulate the mixed solution in each reactor into the temperature controller, so that the temperature of the mixed solution can be accurately adjusted through the temperature controller after completing the first stage of heating, so that the mixed solution in each reactor can reach the expected reaction temperature of the second stage, and then be fully heated and pressurized in the main reaction chamber to achieve the simultaneous preparation of multiple CeO2 samples. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 It is a structural schematic diagram of the present invention;

[0042] Figure 2 Schematic diagram of the structure of the circulating liquid pumping unit in the present invention;

[0043] Figure 3Schematic diagram of the cross-sectional structure of the circulating liquid pumping unit in the present invention;

[0044] Figure 4 Schematic diagram of the structure of the temperature controller in the present invention;

[0045] Figure 5 This is a front view of the thermostat of the present invention;

[0046] In the figure: 1. Water heating box; 11. Vacuum heating box; 12. Separation layer; 13. Main reaction chamber; 14. Auxiliary reaction chamber; 15. Spring base; 2. Reactor; 3. Circulating pumping unit; 31. Reactor cover; 32. Connecting rod; 33. Drain seat; 34. Drain pipe; 35. Pumping pipe; 36. Rotating pipe; 37. Pump chamber; 38. Liquid guide pipe; 39. Impeller; 310. Drive shaft; 311. Reflux pipe; 312. Inner pipe; 4. Temperature controller; 41. Cylinder; 42. Partition; 43. Lining plate; 44. Guide bar; 45. Bottom plate; 46. Upper flow port; 47. Lower flow port; 48. External pipe; 5. Outer ring frame; 51. Support rod; 52. Pneumatic telescopic rod. DETAILED DESCRIPTION

[0047] See also Figure 1-Figure 5 In an embodiment of the present invention, a device for efficiently preparing CeO2 using a hydrothermal method comprises:

[0048] The water heating box 1 has a vacuum heating box 11 on its upper end surface. The vacuum heating box 11 is externally connected to a vacuum pump for vacuuming the interior thereof.

[0049] A partition plate 12 is fixed horizontally in the middle of the vacuum heating box 11. The partition plate 12 divides the interior of the vacuum heating box 11 into a main reaction chamber 13 and a secondary reaction chamber 14, with the main reaction chamber 13 located above the secondary reaction chamber 14.

[0050] There are multiple placement slots arranged and evenly distributed on the upper end surface of the separation layer 12. A spring base 15 is installed in each placement slot; the spring base 15 can form a bottom support for the reactor 2, making it easy to install and remove the reactor 2.

[0051] Reactors 2 are provided corresponding to the spring bases 15, and a pre-prepared mixed solution is stored in each of the reactors 2; the mixed solution is a mixture of sodium hydroxide solution and Ce(III) salt solution, wherein, when dissolving the raw materials, cerium nitrate hexahydrate is first dissolved in an appropriate amount of deionized water and stirred until completely dissolved to form a transparent Ce(III) salt solution, and then sodium hydroxide is dissolved in an appropriate amount of deionized water and stirred until completely dissolved to form a sodium hydroxide solution;

[0052] The circulating liquid pumping units 3 are arranged above the interior of the vacuum heating box 11, and each of the circulating liquid pumping units 3 is arranged corresponding to the placement slots, and the circulating liquid pumping units 3 are vertically facing the reactor 2 and are detachably threaded and sealed to the reactor;

[0053] The temperature controller 4 is installed in the secondary reaction chamber, and the liquid extraction end and the liquid discharge end of the circulating liquid extraction unit 3 are both connected to the temperature controller 4; after the solution in the reactor 2 is heated and reacted in the main reaction chamber 13 and the first stage of heating is completed, the circulating liquid extraction unit 3 performs liquid extraction circulation, and the temperature controller 4 dynamically adjusts the heating temperature according to the current temperature of the mixed solution in the reactor 2, thereby providing heating assistance, so that the mixed solution in each reactor 2 reaches the corresponding expected reaction temperature, so that the mixed solution in the subsequent reactor 2 can be completely reacted in the main reaction chamber 13, so as to ensure that the mixed solution in each reactor 2 can reach the expected reaction temperature before the final heating and pressurization, thereby ensuring the preparation stability and consistency of cerium dioxide in each reactor 2, and avoiding differences in the reaction preparation of cerium dioxide.

[0054] In this embodiment, each of the temperature controllers 4 is provided with a temperature sensor (not shown in the figure), and the temperature sensor is used to monitor the current temperature of the mixed solution in real time.

[0055] As a preferred embodiment, the circulating pumping unit 3 includes:

[0056] The kettle cover 31 is threadedly connected to the reactor 2. A connecting rod 32 is vertically fixed to the upper part of the vacuum heating box 11. The lower end of the connecting rod 32 is fixed to the kettle cover 31.

[0057] The drain seat 33 is fixed to the upper end of the connecting rod 32. Two drain channels are symmetrically provided on the drain seat 33. A drain pipe 34 is connected to each drain channel.

[0058] The liquid extraction pipe 35 is vertically connected and fixed on the reactor cover 31, and the lower end of the liquid extraction pipe 35 is deeply inserted into the reactor 2;

[0059] A rotating tube 36 is connected to the upper end of the liquid extraction tube 35;

[0060] The pump chamber 37 is arranged above the drainage seat 33. A liquid guide tube 38 is vertically connected to the bottom of the pump chamber 37 and is connected to the drainage seat 33 through the liquid guide tube 38. The other end of the rotating tube 36 is horizontally connected to the side wall of the pump chamber 37.

[0061] An impeller 39 is rotatably connected to the pump chamber 37, and a drive shaft 310 is provided above the pump chamber 37, one end of the drive shaft 310 is connected to the impeller 39;

[0062] A reflux pipe 311 is provided on one side of the pump chamber 37 , one end of the reflux pipe 311 is connected to the temperature controller 4 , and the other end thereof is vertically connected to the side wall of the liquid extraction pipe 35 ;

[0063] The inner tube 312 is cocentrically arranged in the liquid extraction tube 35, and the reflux tube 311 is sealed and connected to the inner tube 312, that is, the liquid extraction tube 35 can extract the mixed solution in the reactor and send it into the temperature controller 4, while the inner tube 312 sends the mixed solution back into the reactor, thereby completing the flow cycle.

[0064] In this embodiment, the driving shaft 310 drives the impeller 39 to rotate, pumping the mixed solution in the reactor 2 into the pump chamber 37 through the liquid extraction pipe 35, and diverting it into the temperature controller 4 through each discharge pipe 34. The mixed solution discharged from the temperature controller 4 enters the reflux pipe 311 and finally flows into the bottom of the reactor 2 through the inner pipe 312, thereby achieving complete pumping of the mixed solution in the reactor and ensuring its flow integrity.

[0065] In this embodiment, the lower end of the inner tube 312 extends deep into the bottom of the reactor 2, and the distance between the inner tube 312 and the inner wall of the bottom of the reactor 2 is no more than 2 cm. It should be noted that a solenoid valve is provided on the rotating tube 36. When the mixed solution in the reactor is completely circulated and reaches the expected reaction temperature of the second stage, the solenoid valve can control the rotating tube 36 to close, so that the extraction pipe cannot extract the mixed solution in the reactor, and the impeller 39 can almost completely return the mixed solution entering the temperature controller 4 to the reactor through the reflux pipe 311 during a period of idling. It is necessary to accurately control the idling time of the impeller to avoid damage to the equipment due to excessive idling (the above belongs to the prior art and will not be elaborated).

[0066] In this embodiment, the temperature controller 4 includes:

[0067] The cylinder 41 has a temperature regulator installed inside. The side wall of the cylinder 41 is provided with an annular cavity. Two partitions 42 are vertically symmetrically arranged in the annular cavity. The partitions 42 divide the annular cavity into two flow channels. The drainage pipes 34 in the circulating pumping unit 3 are connected to the flow channels; that is, the mixed solution in the drainage pipes 34 can enter each flow channel respectively.

[0068] There are multiple lining plates 43 evenly arranged, and each lining plate 43 is vertically fixed in the flow channel;

[0069] A guide bar 44 is provided corresponding to each of the lining plates 43 , one end of the guide bar 44 is connected to the lining plate 43 , a bottom support plate 45 is provided in the flow channel, and the cross section of the bottom support plate 45 is an arc-shaped structure, and the other end of the guide bar 44 is fixed to the bottom support plate 45 ;

[0070] Upper flow ports 46 are provided on the sidewalls of the liner plates 43 at even-numbered positions, and lower flow ports 47 are provided on the sidewalls of the guide bars 44 at odd-numbered positions, so that the mixed solution can form an S-shaped flow trajectory in the flow channel through the upper flow ports 46 and the lower flow ports 47.

[0071] The external pipes 48 are vertically connected to the outside of each of the flow channels. A horizontal pipe is connected between the external pipes 48 , and the return pipe 311 in the circulating pumping unit 3 is connected to the horizontal pipe.

[0072] As a preferred embodiment, the guide bar 44 is slidably connected to the liner 43, and the bottom support plate 45 slides along the axial direction of the cylinder 41. An outer ring frame 5 is coaxially provided below the cylinder 41. A support rod 51 is vertically connected to the outer ring frame 5, and the upper end of the support rod is connected to the bottom support plate;

[0073] A pneumatic telescopic rod 52 is fixed to the cylinder 41 , and a telescopic end of the pneumatic telescopic rod 52 is connected to the outer ring frame 5 .

[0074] In this embodiment, the outer ring frame 5 adjusts the effective flow area in the flow channel during the up and down sliding adjustment, so that the mixed solution is heat-conducted and temperature-controlled in the temperature controller 4 along a flow trajectory of corresponding length, which facilitates precise heating assistance of the mixed solution.

[0075] In this embodiment, a method for efficiently preparing CeO2 using a hydrothermal method comprises the following steps:

[0076] S1. Selecting cerium nitrate hexahydrate, sodium hydroxide and deionized water as the relevant raw materials for preparation, and dissolving the raw materials, wherein the cerium nitrate hexahydrate is dissolved in a predetermined amount of deionized water and completely stirred and dissolved by a magnetic stirrer to form a transparent solution, while sodium hydroxide is dissolved in a predetermined amount of deionized water to form a sodium hydroxide solution; then slowly adding the sodium hydroxide solution to the transparent solution while stirring, and adjusting the pH value of the solution;

[0077] S2. The solution is divided into multiple portions and transferred to each reactor 2, and then the reactors 2 are screwed together under the reactor cover 31 in the circulating liquid extraction unit 3. At this time, the liquid extraction tube 35 and the inner tube 312 can be immersed in the mixed solution in the reactor 2. The door of the vacuum heating box 11 is closed and vacuum heating is performed;

[0078] S3. Maintain the reaction temperature of the vacuum heating box 11 at 120°C for a predetermined period of 4-6 hours, start the circulating pumping unit 3 to allow the mixed solution in each reactor 2 to enter the temperature controller 4, and obtain the current temperature of the mixed solution from the temperature sensor in each temperature controller 4; then, the temperature controller 4 adjusts the heating power according to the respective temperature data to ensure that the temperature of the solution in each reactor 2 reaches the expected reaction temperature of the second stage.

[0079] S4. The mixed solution is finally heated to 180°C in the main reaction chamber 13 for 12 hours. After the reaction is completed, the heating device of the vacuum heating box 11 is turned off, the reactor 2 is removed from the vacuum heating box 11, and naturally cooled to room temperature.

[0080] S5. The reaction products are separated, washed, and completely dried, and finally calcined in a combustion furnace.

[0081] The above is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with this technical field, within the technical scope disclosed by the present invention, who makes equivalent replacements or changes based on the technical solutions and inventive concepts of the present invention, should be covered by the scope of protection of the present invention.

Claims

1. An efficient preparation method using hydrothermal method The device is characterized in that: include: The water heating box has a vacuum heating box on its upper end surface, and a vacuum pump is connected to the outside of the vacuum heating box for vacuuming its interior; The partition plate is fixed horizontally in the middle of the vacuum heating box. The partition plate divides the interior of the vacuum heating box into a main reaction chamber and a secondary reaction chamber, with the main reaction chamber located above the secondary reaction chamber. The placement slots are arranged in a plurality and evenly distributed on the upper end surface of the separation layer, and a spring base is installed in each placement slot; Reactors are provided corresponding to the spring bases, and a plurality of reactors are provided with pre-prepared mixed solutions; The circulating liquid pumping unit is arranged above the interior of the vacuum heating box. Each circulating liquid pumping unit is arranged corresponding to the placement slot. The circulating liquid pumping unit is vertically facing the reactor and is detachably threaded and sealed with the reactor. The temperature controller is installed in the auxiliary reaction chamber, and the liquid extraction end and the liquid discharge end of the circulating liquid extraction unit are both connected to the temperature controller; After the solution in the reactor is heated and reacted in the main reaction chamber and the first stage of heating is completed, the circulating liquid pumping unit performs liquid pumping circulation. The temperature controller dynamically adjusts the heating temperature according to the current temperature of the mixed solution in the reactor, thereby providing heating assistance, so that the mixed solution in each reactor reaches the corresponding expected reaction temperature, so that the mixed solution in the subsequent reactor can fully react in the main reaction chamber; The circulating pumping unit includes a connecting rod, a drain seat, a pump chamber and a return pipe. The connecting rod is vertically fixed on the upper part of the vacuum heating box. The drain seat is fixed to the upper end of the connecting rod. Two drainage channels are symmetrically arranged on the drain seat. Each drainage channel is connected to a drainage pipe. The pump chamber is arranged above the drain seat, and the return pipe is arranged on one side of the pump chamber. Thermostat includes: The cylinder has a temperature regulator installed inside and an annular cavity on its side wall. Two partitions are vertically symmetrically arranged in the annular cavity. The partitions divide the annular cavity into two flow channels. The drainage pipes in the circulating pumping unit are connected to the flow channels. There are multiple lining plates evenly arranged, each lining plate is vertically fixed in the flow channel; A guide bar is provided corresponding to each liner, one end of the guide bar is connected to the liner, a bottom support plate is provided in the flow channel, the cross section of the bottom support plate is an arc-shaped structure, and the other end of the guide bar is fixed to the bottom support plate; The upper flow port is provided on the side wall of each lining plate at an even number position; the lower flow port is provided on the side wall of each guide bar at an odd number position; External pipes are vertically connected to the outside of each flow channel. There are horizontal pipes between the external pipes, and the return pipe in the circulating pumping unit is connected to the horizontal pipe; The guide bar is slidably connected to the liner, and the bottom support plate slides along the axial direction of the cylinder. An outer ring frame is coaxially arranged below the cylinder, and a support rod is vertically connected to the outer ring frame. The upper end of the support rod is connected to the bottom support plate; A pneumatic telescopic rod is fixed on the cylinder body, and the telescopic end of the pneumatic telescopic rod is connected with the outer ring frame.

2. The method according to claim 1, wherein the hydrothermal method is used to efficiently prepare The device is characterized in that: Each temperature controller is provided with a temperature sensor, which is used to monitor the current temperature of the mixed solution in real time.

3. The method according to claim 1, wherein the hydrothermal method is used to efficiently prepare The device is characterized in that: The circulating pumping unit also includes: The kettle cover is threadedly connected to the reactor, and the lower end of the connecting rod is fixed to the kettle cover; The liquid extraction pipe is vertically connected and fixed on the reactor cover, and the lower end of the liquid extraction pipe is deeply inserted into the reactor; A rotating tube connected to the upper end of the liquid extraction tube; The impeller is rotatably connected in the pump chamber, and a drive shaft is provided above the pump chamber, one end of the drive shaft is connected to the impeller; The inner tube is co-centeredly arranged in the liquid extraction tube, and the return tube is sealed and connected to the inner tube; A liquid guide tube is vertically connected to the bottom of the pump chamber and is connected to the liquid drain seat through the liquid guide tube; the other end of the rotating tube is horizontally connected to the side wall of the pump chamber; One end of the reflux pipe is connected to the temperature controller, and the other end thereof is vertically connected to the side wall of the liquid extraction pipe.

4. The method according to claim 3, wherein the hydrothermal method is used to efficiently prepare The device is characterized in that: The driving shaft drives the impeller to rotate, pumping the mixed solution in the reactor into the pump chamber through the liquid extraction pipe, and then diverting it into the temperature controller through each discharge pipe. The mixed solution discharged from the temperature controller enters the reflux pipe and finally flows into the bottom of the reactor through the inner pipe.

5. The method according to claim 3, wherein the hydrothermal method is used to efficiently prepare The device is characterized in that: The lower end of the inner tube reaches the bottom of the reactor, and the distance between the lower end of the inner tube and the inner wall of the bottom of the reactor is no more than 2 cm.

6. The method according to claim 1 for efficiently preparing the The device is characterized in that: The outer ring frame is slid up and down to adjust the effective flow area in the flow channel, so that the mixed solution is heat-conducted and temperature-controlled in the temperature controller along a flow track of corresponding length.

7. An efficient preparation method using hydrothermal method The method is to use a hydrothermal method as described in any one of claims 1 to 6 to efficiently prepare The device is characterized in that The following steps are involved: S1. Selecting cerium nitrate hexahydrate, sodium hydroxide and deionized water as the relevant raw materials for preparation, and dissolving the raw materials, wherein the cerium nitrate hexahydrate is dissolved in a predetermined amount of deionized water and completely stirred and dissolved by a magnetic stirrer to form a transparent solution, and sodium hydroxide is dissolved in a predetermined amount of deionized water to form a sodium hydroxide solution; then slowly adding the sodium hydroxide solution to the transparent solution while stirring, and adjusting the pH value of the solution; S2. The solution is divided into multiple portions and transferred to each reactor, and then the reactors are spirally mounted under the reactor cover in the circulating liquid extraction unit. At this time, the liquid extraction tube and the inner tube can be immersed in the mixed solution in the reactor, the door of the vacuum heating box is closed and vacuum heating is performed; S3. Maintain the reaction temperature of the vacuum heating box at 120°C for a predetermined time for 4-6 hours, start the circulating pumping unit so that the mixed solution in each reactor enters the thermostat, and the temperature sensor in each thermostat obtains the current temperature of the mixed solution; and then the thermostat adjusts the heating power according to the respective temperature data to ensure that the solution temperature in each reactor reaches the expected reaction temperature in the second stage; S4. The mixed solution was finally heated to 180°C in the main reaction chamber for 12 hours. After the reaction, the heating device of the vacuum heating box was turned off, and the reactor was removed from the vacuum heating box and cooled naturally to room temperature. S5. The reaction products are separated, washed, and completely dried, and finally calcined in a combustion furnace.

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