Preparation method of high-purity hafnium oxide

Abstract

The invention discloses a preparation method of high-purity hafnium oxide, and relates to the technical field of hafnium oxide preparation, and the preparation method comprises the following steps: S1, dissolving raw materials; s2, solution pretreatment; s3, extracting and separating; s4, back extraction; s5, precipitating and calcining; and S6, waste liquid recovery. According to the preparation method of the high-purity hafnium oxide, by optimizing extraction agent selection, solution condition control and subsequent treatment steps, target metal ions are separated from the solution through the selective extraction agent, impurities can be effectively removed, the hafnium oxide with high purity and excellent performance can be prepared, the method has the advantages of being easy to operate, high in raw material adaptability, environmentally friendly and the like, and the method is suitable for industrial production. The device has a wide application prospect, and the second nozzle and the first nozzle alternately spray water through switches of the second electronic valve and the first electromagnetic valve, so that the surface of the stirring paddle and the inner surface of the kettle body can be comprehensively flushed, the interior of the kettle body does not need to be opened and exposed, manual operation is not needed, and the manual cleaning cost is greatly reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of hafnium oxide preparation, and specifically to a method for preparing high-purity hafnium oxide. Background Art

[0002] Hafnium oxide (HfO2) is an important high-performance material with high melting point, high dielectric constant, excellent chemical stability and thermal stability, and is widely used in the fields of microelectronics, optical coatings, nuclear industry and catalyst carriers. Especially in the semiconductor industry, hafnium oxide is used as a high-dielectric constant (high-k) material to replace traditional silicon dioxide (SiO2) as the gate dielectric layer, which can significantly improve device performance. With the rapid development of industries such as semiconductors, chips, military, and nuclear power in China, the demand for high-purity hafnium products is increasing continuously. At present, MIBK and TBP extraction methods are mainly used in China to separate zirconium and hafnium. The hafnium oxide prepared after separation has a high impurity content. Especially, the zirconium content cannot reach below 0.5%, and the main content cannot reach the high-purity level above 99.9%. The research demand for the efficient preparation technology of high-purity low-zirconium hafnium oxide is urgent. Summary of the Invention

[0003] Aiming at the deficiencies of the prior art, the present invention provides a method for preparing high-purity hafnium oxide, which solves the problems mentioned in the above background art.

[0004] To achieve the above purposes, the present invention is realized through the following technical solutions: A method for preparing high-purity hafnium oxide, the method for preparing high-purity hafnium oxide includes the following steps: S1. Raw material dissolution: Mix hafnium-containing raw materials such as zircon sand or hafnium-containing waste with concentrated sulfuric acid or hydrofluoric acid in a stirring reaction kettle, heat and dissolve to obtain a hafnium-containing liquor; S2. Solution pretreatment: Pretreat the hafnium-containing liquor with an extractant or alcoholized acid, and perform countercurrent acidification on the extractant and alcoholized acid; S3. Extraction and separation: Mix the pretreated organic phase with the liquor, and perform multi-stage countercurrent extraction to selectively separate hafnium ions; S4. Back extraction: Wash the hafnium-containing organic phase after countercurrent extraction with a weak acid solution, and perform back extraction on the hafnium-loaded organic phase with dilute acid to obtain a high-purity hafnium solution; S5. Precipitation and calcination: Add ammonia water or sodium hydroxide to the high-purity hafnium solution to form hafnium hydroxide precipitate. After washing and drying, calcine at high temperature to obtain high-purity hafnium oxide; S6. Waste liquid recovery: Add ammonia water or sodium hydroxide to the aqueous phase produced by extraction separation to form a precipitate, wash, dry, calcine, and recover zirconium. The mother liquor enters the sewage treatment system.

[0005] Furthermore, in the step S2, the extractant composition is 10-20% phosphoric acid, 5-10% mixed alcohol, and 50-70% sulfonated kerosene; the alcoholized acid is 1.5-2 mol / L sulfuric acid.

[0006] Furthermore, in the step S3, the organic phase acidified in the step S2 is mixed with the feed liquid in the step S1 at a volume ratio of 1:1-1.5, and 5-6 stages of countercurrent extraction are carried out to separate hafnium ions.

[0007] Furthermore, in the step S4, the hafnium-containing organic phase after countercurrent extraction is washed with a 10-20% oxalic acid solution for 4 stages, and the washed organic phase is subjected to 3-4 stages of back extraction with a 1.5-3 mol / L ammonium bicarbonate solution or a 1.5 mol / L nitric acid solution.

[0008] Furthermore, in the step S5, ammonia water is slowly added to the high-purity hafnium solution to adjust the pH value to 8 to form a hafnium hydroxide precipitate. After washing and drying, it is calcined at 850 °C for 3 hours to obtain high-purity hafnium oxide.

[0009] Furthermore, in the step S5, sodium hydroxide is slowly added to the high-purity hafnium solution to adjust the pH value to 9 to form a hafnium hydroxide precipitate. After washing and drying, it is calcined at 950 °C for 2.5 hours to obtain high-purity hafnium oxide.

[0010] Furthermore, the preparation method of the high-purity hafnium oxide is applied with a stirring reaction kettle, and the stirring reaction kettle includes a kettle body, and a stirring assembly is arranged at the top of the kettle body.

[0011] Furthermore, the stirring assembly includes a driving motor, a telescopic push rod, a hollow shaft, and a stirring paddle. The bottom of the driving motor is connected with a telescopic push rod, and the bottom of the telescopic push rod is connected with a hollow shaft. Stirring paddles are arranged on the outer wall of the hollow shaft.

[0012] Furthermore, the stirring assembly further includes a first solenoid valve and a plug connector. A first solenoid valve is arranged at the bottom of the hollow shaft, and a plug connector is fixed at the bottom of the first solenoid valve.

[0013] Furthermore, the stirring assembly further includes a water inlet pipe, a second solenoid valve, a right-angle turntable, a cleaning brush, a first spray head, and a second spray head. A water inlet pipe penetrates through the bottom of the kettle body below the plug connector, and the top of the water inlet pipe is connected with a right-angle turntable through a second solenoid valve. The right-angle turntable is rotatably connected with the kettle body, a cleaning brush is arranged on the outer side surface of the right-angle turntable, first spray heads are distributed on the inner side surface of the right-angle turntable, and second spray heads are distributed on the surface of the stirring paddle.

[0014] The present invention provides a method for preparing high-purity hafnium oxide, which has the following beneficial effects: 1. In this method for preparing high-purity hafnium oxide, by optimizing the selection of extractant, controlling the solution conditions and subsequent treatment steps, and separating target metal ions from the solution through a selective extractant, impurities can be effectively removed, the product purity can be improved, high-purity hafnium oxide with excellent performance can be prepared, and at the same time, the production cost can be reduced. It is suitable for industrial applications. This method has the advantages of simple operation, strong raw material adaptability, environmental friendliness, etc., and has broad application prospects.

[0015] 2. In this method for preparing high-purity hafnium oxide, when cleaning is required each time, whether the right-angle turntable is driven to rotate by the lifting of the plug connector is self-rotated, and the second nozzle and the first nozzle are alternately sprayed with water by the opening and closing of the second electronic valve and the first solenoid valve. Thus, the surface of the stirring paddle and the inner surface of the kettle body can be comprehensively rinsed, without opening the inside of the kettle body and without manual operation, thereby greatly reducing the manual cleaning cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic flow chart of the steps of a method for preparing high-purity hafnium oxide according to the present invention; Figure 2 It is a schematic structural diagram of the kettle body of the present invention; Figure 3 It is a schematic structural diagram of the hollow shaft of the present invention; Figure 4 It is a schematic structural diagram of the right-angle turntable of the present invention; Figure 5 It is a schematic structural diagram of the bottom of the kettle body of the present invention.

[0017] In the figure: 1, kettle body; 2, stirring assembly; 201, driving motor; 202, telescopic push rod; 203, hollow shaft; 204, stirring paddle; 205, first solenoid valve; 206, plug connector; 207, water inlet pipe; 208, second electronic valve; 209, right-angle turntable; 210, cleaning brush; 211, first nozzle; 212, second nozzle. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0018] The following further describes in detail the embodiments of the present invention with reference to the drawings and embodiments. The following embodiments are used to illustrate the present invention, but cannot be used to limit the scope of the present invention.

[0019] As Figure 1 shown, the present invention provides a technical solution: a method for preparing high-purity hafnium oxide, and the method for preparing high-purity hafnium oxide includes the following steps: S1. Raw material dissolution: Mix hafnium-containing raw materials such as zircon or hafnium-containing waste with concentrated sulfuric acid or hydrofluoric acid in a stirred reaction kettle, heat and dissolve to obtain a hafnium-containing feed solution; S2. Solution pretreatment: Pretreat the hafnium-containing feed solution with an extractant or alcoholized acid, and carry out countercurrent acidification of the extractant and alcoholized acid; S3. Extraction and separation: Mix the pretreated organic phase with the feed solution, carry out multi-stage countercurrent extraction, and selectively separate hafnium ions; S4. Back extraction: Wash the hafnium-containing organic phase after countercurrent extraction with a weak acid solution, and carry out back extraction of the hafnium-loaded organic phase with dilute acid to obtain a high-purity hafnium solution; S5. Precipitation and calcination: Add ammonia water or sodium hydroxide to the high-purity hafnium solution to form hafnium hydroxide precipitate. After washing and drying, calcine at high temperature to obtain high-purity hafnium oxide; S6. Waste liquid recovery: Add ammonia water or sodium hydroxide to the aqueous phase generated by extraction and separation to form a precipitate, wash, dry, calcine, and recover zircon. The mother liquor enters the sewage treatment system; In step S2, the composition of the extractant is 10-20% phosphoric acid, 5-10% mixed alcohol, 50-70% sulfonated kerosene; alcoholized acid: 1.5-2 mol / L sulfuric acid; In step S3, the organic phase acidified in step S2 is mixed with the feed solution in step S1 at a volume ratio of 1:1-1.5, and 5-6 stages of countercurrent extraction are carried out to separate hafnium ions; In step S4, the hafnium-containing organic phase after countercurrent extraction is washed 4 times with a 10-20% oxalic acid solution, and the washed organic phase is subjected to 3-4 stages of back extraction with a 1.5-3 mol / L ammonium bicarbonate solution or a 1.5 mol / L nitric acid solution; In step S5, slowly add ammonia water to the high-purity hafnium solution to adjust the pH value to 8, form hafnium hydroxide precipitate. After washing and drying, calcine at 850 °C for 3 hours to obtain high-purity hafnium oxide; In step S5, slowly add sodium hydroxide to the high-purity hafnium solution to adjust the pH value to 9, form hafnium hydroxide precipitate. After washing and drying, calcine at 950 °C for 2.5 hours to obtain high-purity hafnium oxide; Example

[0020] Raw material dissolution: Mix 100 g of zircon or hafnium compound with 250 ml of concentrated sulfuric acid, heat to 230 °C, react for 5 hours to obtain a hafnium sulfate feed solution with an acidity of 1.5-2.5 mol / L and a hafnium oxide concentration of 3-10 g / L; Solution pretreatment: Prepare an extractant, alcoholized acid, etc. The composition of the extractant is 10 - 20% phosphoric acid, 5 - 10% mixed alcohol, and 50 - 70% sulfonated kerosene; alcoholized acid: 1.5 - 2 mol / L sulfuric acid; Pretreat the solution by performing 3 - stage countercurrent acidification on the extractant and the alcoholized acid; Extraction and separation: Mix the organic phase acidified in step 2 with the feed liquid in step 1 at a volume ratio of 1:1, and perform 6 - stage countercurrent extraction to separate hafnium ions; Back - extraction: Wash the hafnium - containing organic phase after countercurrent extraction 4 times with an oxalic acid solution with a concentration of 10 - 20%; Back - extract the washed organic phase 4 times with a 1.5 - 3 mol / L ammonium bicarbonate solution to obtain a high - purity hafnium solution. The hafnium content in the back - extraction liquid zirconium - hafnium mixture is greater than 99.5%; Precipitation and calcination: Slowly add ammonia water to the high - purity hafnium solution to adjust the pH value to 8, form hafnium hydroxide precipitate. After washing and drying, calcine it at 850 °C for 3 hours to obtain high - purity hafnium oxide with a zirconium oxide content of less than 0.5%; Waste liquid recovery: Add ammonia water to the aqueous phase generated during extraction and separation to adjust the pH value to 8, form zirconium hydroxide precipitate. After washing and drying, calcine it at 800 °C for 2 hours to recover zirconium oxide, and the mother liquor enters the sewage treatment system; Examples

[0021] Raw material dissolution: Mix 100 g of ordinary hafnium oxide with 250 ml of hydrofluoric acid, heat to 70 °C, and react for 7 hours to obtain a hafnium - containing feed liquid; Solution pretreatment: Prepare an extractant, alcoholized acid, etc. The composition of the extractant is 10 - 20% phosphoric acid, 5 - 10% mixed alcohol, and 50 - 70% sulfonated kerosene; alcoholized acid: 1.5 - 2 mol / L sulfuric acid; Pretreat the solution by performing 4 - stage countercurrent acidification on the extractant and the alcoholized acid, and filter out solid impurities; Extraction and separation: Mix the organic phase acidified in step 2 with the feed liquid in step 1 at a volume ratio of 1:1.5, and perform 5 - stage countercurrent extraction to separate hafnium ions; Back - extraction: Wash the hafnium - containing organic phase after countercurrent extraction 4 times with an oxalic acid solution with a concentration of 10 - 20%; Back - extract the washed organic phase 3 times with a 1.5 mol / L nitric acid solution to obtain a high - purity hafnium solution. The hafnium content in the back - extraction liquid zirconium - hafnium mixture is greater than 99.5%; Precipitation and calcination: Slowly add sodium hydroxide to the high - purity hafnium solution to adjust the pH value to 9, form hafnium hydroxide precipitate. After washing and drying, calcine it at 950 °C for 2.5 hours to obtain high - purity hafnium oxide with a zirconium oxide content of less than 0.5%; Waste liquid recovery: Sodium hydroxide is added to the aqueous phase produced by extraction and separation to adjust the pH value to 9, forming zirconium hydroxide precipitate. After washing and drying, it is calcined at 900 °C for 1.5 hours to recover zirconia, and the mother liquor enters the sewage treatment system; Based on the above description, the present invention optimizes the selection of extractant, the control of solution conditions and subsequent treatment steps. By using a selective extractant to separate target metal ions from the solution, it can effectively remove impurities, improve product purity, prepare hafnium oxide with high purity and excellent performance, reduce production costs at the same time, and is suitable for industrial application. This method has the advantages of simple operation, strong raw material adaptability, environmental friendliness, etc., and has broad application prospects.

[0022] As Figures 2 - 5 shown, the preparation method of high-purity hafnium oxide is applied with a stirring reaction kettle. The stirring reaction kettle includes a kettle body 1. A stirring assembly 2 is arranged at the top of the kettle body 1. The stirring assembly 2 includes a driving motor 201, a telescopic push rod 202, a hollow shaft 203 and a stirring paddle 204. The bottom of the driving motor 201 is connected with a telescopic push rod 202, and the bottom of the telescopic push rod 202 is connected with a hollow shaft 203. Stirring paddles 204 are arranged on the outer wall of the hollow shaft 203. The stirring assembly 2 further includes a first solenoid valve 205 and a plug connector 206. A first solenoid valve 205 is arranged at the bottom of the hollow shaft 203, and a plug connector 206 is fixed at the bottom of the first solenoid valve 205. The stirring assembly 2 further includes a water inlet pipe 207, a second solenoid valve 208, a right-angle turntable 209, a cleaning brush 210, a first spray head 211 and a second spray head 212. A water inlet pipe 207 passes through the bottom of the kettle body 1 below the plug connector 206, and the top of the water inlet pipe 207 is connected with a right-angle turntable 209 through a second solenoid valve 208. The right-angle turntable 209 is rotatably connected with the kettle body 1, and a cleaning brush 210 is arranged on the outer side surface of the right-angle turntable 209. The first spray heads 211 are distributed on the inner side surface of the right-angle turntable 209, and the second spray heads 212 are distributed on the surface of the stirring paddle 204; The specific operation is as follows. In the raw material dissolution and mixing step, each raw material is put into the interior of the kettle body 1. At this time, the driving motor 201 drives the telescopic push rod 202 and the hollow shaft 203 to rotate, so that the stirring paddle 204 stirs the liquid material to make it uniformly mixed; After the liquid material is mixed and discharged through the discharge pipe, the interior of the kettle body 1 needs to be cleaned. The second solenoid valve 208 is a multi-way valve. At this time, by adjusting the opened channels, the cleaning water passes through the water inlet pipe 207, passes through the second solenoid valve 208 and the right-angle turntable 209, and sprays from the first spray head 211 onto the surfaces of the hollow shaft 203 and the stirring paddle 204. At this time, the driving motor 201 drives the hollow shaft 203 and the stirring paddle 204 to rotate, so that their surfaces are uniformly washed; Then, the telescopic push rod 202 extends, causing the plug connector 206 to insert into the interior of the second solenoid valve 208. The first solenoid valve 205 is opened, allowing the cleaning water to enter the interior of the stirring paddle 204 along the hollow shaft 203 and spray out from the second spray head 212 towards the inner surface of the kettle body 1. At this time, when the stirring paddle 204 rotates, the right-angle turntable 209 will be driven to rotate together by the plug connector 206, causing the cleaning brush 210 to adhere to the inner surface of the kettle body 1 for scrubbing. The inner surface of the stirring paddle 204 and the inner surface of the kettle body 1 are rinsed by alternately spraying water from the second spray head 212 and the first spray head 211; Based on the above description, each time the present invention needs to be cleaned, it automatically rotates whether to drive the right-angle turntable 209 to rotate through the lifting of the plug connector 206, and alternately sprays water from the second spray head 212 and the first spray head 211 by switching the second solenoid valve 208 and the first solenoid valve 205. Thus, the surfaces of the stirring paddle 204 and the inner surface of the kettle body 1 can be comprehensively rinsed without opening the interior of the kettle body 1 or manual operation, thereby greatly reducing the labor cost of cleaning.

[0023] In summary, for the preparation method of high-purity hafnium oxide, when in use, first, a hafnium-containing raw material such as zircon or hafnium-containing waste is mixed with concentrated sulfuric acid or hydrofluoric acid in a stirring reaction kettle, heated and dissolved to obtain a hafnium-containing liquid; Among them, each raw material is put into the interior of the kettle body 1. At this time, the driving motor 201 drives the telescopic push rod 202 and the hollow shaft 203 to rotate, causing the stirring paddle 204 to stir the liquid to make it evenly mixed; After the liquid is mixed, it is discharged through the discharge pipe. Then, the interior of the kettle body 1 needs to be cleaned. The second solenoid valve 208 is a multi-way valve. At this time, by adjusting the opened channel, the cleaning water passes through the second solenoid valve 208 and the right-angle turntable 209 along the water inlet pipe 207 and sprays out from the first spray head 211 towards the surfaces of the hollow shaft 203 and the stirring paddle 204. At this time, the driving motor 201 drives the hollow shaft 203 and the stirring paddle 204 to rotate, so that their surfaces are evenly rinsed; Then, the telescopic push rod 202 extends, causing the plug connector 206 to insert into the interior of the second solenoid valve 208. The first solenoid valve 205 is opened, allowing the cleaning water to enter the interior of the stirring paddle 204 along the hollow shaft 203 and spray out from the second spray head 212 towards the inner surface of the kettle body 1. At this time, when the stirring paddle 204 rotates, the right-angle turntable 209 will be driven to rotate together by the plug connector 206, causing the cleaning brush 210 to adhere to the inner surface of the kettle body 1 for scrubbing. The inner surface of the stirring paddle 204 and the inner surface of the kettle body 1 are rinsed by alternately spraying water from the second spray head 212 and the first spray head 211; The hafnium-containing liquid is pretreated with an extractant or alcoholized acid, and the extractant and the alcoholized acid are counter-current acidified; The pretreated organic phase is mixed with the liquid, and multi-stage counter-current extraction is carried out to selectively separate hafnium ions; The hafnium-containing organic phase after countercurrent extraction is washed with a weak acid solution, and the hafnium-loaded organic phase is stripped with dilute acid to obtain a high-purity hafnium solution; Ammonia water or sodium hydroxide is added to the high-purity hafnium solution to form hafnium hydroxide precipitate. After washing and drying, it is calcined at high temperature to obtain high-purity hafnium oxide; Ammonia water or sodium hydroxide is added to the aqueous phase generated by extraction separation to form a precipitate, which is washed, dried, calcined, and zircon is recovered. The mother liquor enters the sewage treatment system.

[0024] The embodiments of the present invention are given for purposes of illustration and description, and are not exhaustive or limit the invention to the disclosed form. Many modifications and variations are obvious to those of ordinary skill in the art. The embodiments are chosen and described in order to best explain the principles of the invention and its practical application, and to enable those of ordinary skill in the art to understand the invention so as to design various embodiments with various modifications suitable for a particular purpose.

Claims

1. A method for preparing high-purity hafnium oxide, characterized in that: The method for preparing high-purity hafnium oxide comprises the following steps: S1. Raw material dissolution: Mix hafnium-containing raw materials such as zircon sand or hafnium-containing waste with concentrated sulfuric acid or hydrofluoric acid in a stirring reaction kettle, heat and dissolve to obtain a hafnium-containing liquid; S2. Solution pretreatment: Pretreat the hafnium-containing liquid with an extractant or alcoholized acid, and carry out countercurrent acidification of the extractant and alcoholized acid; S3. Extraction and separation: Mix the pretreated organic phase with the liquid, and carry out multi-stage countercurrent extraction to selectively separate hafnium ions; S4. Back extraction: Wash the hafnium-containing organic phase after countercurrent extraction with a weak acid solution, and carry out back extraction on the hafnium-loaded organic phase with dilute acid to obtain a high-purity hafnium solution; S5. Precipitation and calcination: Add ammonia water or sodium hydroxide to the high-purity hafnium solution to form a hafnium hydroxide precipitate. After washing and drying, calcine at a high temperature to obtain high-purity hafnium oxide; S6. Waste liquid recovery: Add ammonia water or sodium hydroxide to the aqueous phase generated by extraction and separation to form a precipitate, wash, dry, calcine and recover zircon, and the mother liquor enters the sewage treatment system.

2. The preparation method of a high-purity hafnium oxide according to claim 1, characterized in that: In the step S2, the composition of the extractant is 10-20% phosphoric acid, 5-10% mixed alcohol, 50-70% sulfonated kerosene; the alcoholized acid: 1.5-2 mol / L sulfuric acid.

3. The preparation method of a high-purity hafnium oxide according to claim 1, characterized in that: In the step S3, the organic phase acidified in the step S2 is mixed with the liquid in the step S1 at a volume ratio of 1:1-1.5, and 5-6 stages of countercurrent extraction are carried out to separate hafnium ions.

4. The preparation method of a high-purity hafnium oxide according to claim 1, characterized in that: In the step S4, the hafnium-containing organic phase after countercurrent extraction is washed 4 times with a 10-20% oxalic acid solution, and the washed organic phase is subjected to 3-4 stages of back extraction with a 1.5-3 mol / L ammonium bicarbonate solution or a 1.5 mol / L nitric acid solution.

5. The preparation method of a high-purity hafnium oxide according to claim 1, characterized in that: In the step S5, slowly add ammonia water to the high-purity hafnium solution to adjust the pH value to 8 to form a hafnium hydroxide precipitate. After washing and drying, calcine at 850 °C for 3 hours to obtain high-purity hafnium oxide.

6. The preparation method of a high-purity hafnium oxide according to claim 1, characterized in that: In the step S5, slowly add sodium hydroxide to the high-purity hafnium solution to adjust the pH value to 9 to form a hafnium hydroxide precipitate. After washing and drying, calcine at 950 °C for 2.5 hours to obtain high-purity hafnium oxide.

7. The preparation method of a high-purity hafnium oxide according to claim 1, characterized in that: The method for preparing high-purity hafnium oxide uses a stirring reaction kettle, and the stirring reaction kettle comprises a kettle body (1), and a stirring assembly (2) is arranged at the top of the kettle body (1).

8. The preparation method of a high-purity hafnium oxide according to claim 7, characterized in that: The stirring assembly (2) comprises a driving motor (201), a telescopic push rod (202), a hollow shaft (203) and a stirring paddle (204). The bottom of the driving motor (201) is connected with the telescopic push rod (202), and the bottom of the telescopic push rod (202) is connected with the hollow shaft (203). The outer wall of the hollow shaft (203) is provided with the stirring paddle (204).

9. The preparation method of a high-purity hafnium oxide according to claim 8, characterized in that: The stirring assembly (2) further comprises a first electromagnetic valve (205) and a plug connector (206). The bottom of the hollow shaft (203) is provided with the first electromagnetic valve (205), and the bottom of the first electromagnetic valve (205) is fixed with the plug connector (206).

10. The preparation method of a high-purity hafnium oxide according to claim 9, characterized in that: The stirring assembly (2) further includes a water inlet pipe (207), a second solenoid valve (208), a right-angle turntable (209), a cleaning brush (210), a first spray head (211), and a second spray head (212). A water inlet pipe (207) is penetrated through the bottom of the kettle body (1) below the plug connector (206), and the top of the water inlet pipe (207) is connected to a right-angle turntable (209) through a second solenoid valve (208). The right-angle turntable (209) is rotatably connected to the kettle body (1), and a cleaning brush (210) is arranged on the outer side surface of the right-angle turntable (209). The inner side surface of the right-angle turntable (209) is distributed with first spray heads (211), and the surface of the stirring paddle (204) is distributed with second spray heads (212).

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