Preparation method of high-sphericity nano zirconium oxide powder

Abstract

The invention discloses a preparation method of high-sphericity-degree nano zirconium oxide powder, which comprises the following steps: 1) weighing a precipitant, dissolving the precipitant in deionized water to obtain a solution A, weighing zirconium salt and rare earth salt, mixing and dissolving the zirconium salt and the rare earth salt in deionized water to obtain a solution B; 2) adding the solution A and the solution B into a supergravity reactor, adjusting the reaction temperature and rotation speed in the supergravity reactor, and mixing and precipitating to obtain a precursor solution; 3) aging, filtering and washing the precursor solution to obtain a precursor; and 4) calcining the precursor to obtain the high-sphericity nano zirconium oxide powder. The zirconium oxide powder prepared by the method is in monodisperse distribution, the particle size range D50 is 0.02-0.2 mu m, the particle sphericity is greater than or equal to 80%, and the particle size distribution is narrow.

Description

Technical Field

[0001] This invention belongs to the field of nanomaterial preparation technology, and in particular relates to a method for preparing highly spherical nano-zirconia powder. Background Technology

[0002] Zirconia, with its high wear resistance, high fracture toughness, excellent thermal shock resistance, and good biocompatibility, holds an irreplaceable position in fields such as refractory materials, solid-state batteries, bioceramics, dental veneers, and optical composite films. Nanoscale zirconia powder, due to its large specific surface area and high surface activity, can further endow materials with superior sintering activity and functional properties, making it a key raw material for high-end applications. Among these, sphericity, particle size, and dispersibility are core indicators determining its performance upper limit, directly affecting the powder's bulk density, flowability, degree of sintering densification, and the mechanical strength and optical properties of subsequent products.

[0003] From a market demand and application perspective, the global zirconia market reached $791 million in 2022 and is projected to grow to $1.102 billion by 2031. The demand for nano-zirconia powder is particularly strong in high-end fields such as dental restorations and optical devices. For example, dental veneers require zirconia powder with high sphericity and nanoscale particle size to ensure the mechanical strength and light transmittance of the formed preform; optical composite films rely on uniformly dispersed small-diameter spherical powder to reduce light scattering and ensure stable light transmittance. However, global zirconium resources are highly concentrated in countries such as South Africa and Australia. To achieve domestic substitution in this highly competitive market, breakthroughs are urgently needed in the efficient preparation technology of nano-zirconia powder that combines high sphericity and good dispersibility to meet the stringent performance requirements of high-end fields.

[0004] The preparation methods of zirconia powder are mainly divided into physical methods and chemical methods. Physical methods, such as high-energy mechanical ball milling, can prepare fine-particle-size powders, but the equipment is complex, energy consumption is high, and it is difficult to control the sphericity of the powder. At the same time, the violent mechanical action can easily introduce impurities and destroy the dispersion stability, making it unsuitable for high-end applications. Chemical methods have become the mainstream due to their strong process controllability, including gas-phase methods, liquid-phase methods (co-precipitation method, hydrothermal method, sol-gel method, etc.) and solid-phase methods. Liquid-phase methods are the main choice for industrial production due to their lower cost and easy control of composition. Among them, the coprecipitation method relies on rapid titration reaction, which is prone to local uneven concentration, resulting in severe powder agglomeration and wide particle size distribution. Moreover, the crystal growth is disordered during precipitation, making it difficult to form powder with high sphericity. Although the hydrothermal method can improve powder dispersibility and grain refinement by controlling temperature and pressure, the equipment cost is high, the reaction cycle is long, the economics of large-scale production are poor, and powder agglomeration is still prone to occur in high-concentration systems. The sol-gel method uses expensive raw materials, and hard agglomeration is prone to occur due to capillary force during gel drying. The powder is mostly irregular particles, and the sphericity is difficult to control. At the same time, the porosity is prone to be high after sintering.

[0005] Currently, the preparation of high sphericity zirconia powder generally requires special equipment, harsh reaction conditions (high temperature and high pressure), multiple steps, and long time, resulting in high costs and hindering large-scale production.

[0006] For example, Chinese patent application CN116262662A discloses a reaction using zirconium oxychloride and urea as raw materials, in a high-pressure reactor at 6-16 MPa and 160-200 ℃ for 12-18 h, followed by washing and calcination. This method relies on high-pressure equipment and has a long reaction time.

[0007] For example, Chinese patent application CN116102350A discloses a method for preparing high sphericity zirconia powder through eight steps, including hydrothermal treatment, pH adjustment, filtration and washing, calcination, grinding, and spray granulation. However, the steps are complicated and require specialized granulation equipment.

[0008] For example, Chinese patent application CN111908504A discloses a method for preparing high-sphericity zirconia powder by first chlorinating zircon sand and other raw materials at 850-950 ℃ for 15-18 h, then reducing it with mixed gas, then hydrolyzing it into a gel, and finally calcining it at 600-800 ℃. However, the chlorination conditions are harsh and the energy consumption is high.

[0009] For example, Chinese patent application CN109776092A uses SDS, n-decyl alcohol and water as liquid crystal templates, mixes citric acid and zirconium oxynitrate to adjust the pH to 8-12, and centrifuges and calcines to prepare zirconium oxide powder with high sphericity. However, its template agent is expensive and the ratio is very precise.

[0010] For example, Chinese patent application CN112340773A discloses a method for preparing nano-zirconia luminescent materials. This method employs a continuous operation in a rotating bed under high gravity, where the reactants have a very short residence time in the reactor, and the reaction products leave the reactor immediately after formation, which can significantly improve production efficiency. However, this method uses a hydrothermal post-processing method, relies on high-pressure equipment, has a long reaction time, and produces poor sphericity, making it unsuitable for fields such as dental veneers and bioceramics.

[0011] In summary, developing a method that is simple, low-cost, low-energy, and capable of stably preparing nano-zirconia powder with high sphericity and good dispersibility has become the key to meeting the needs of high-end fields such as dental veneers and promoting the transformation of my country's zirconia industry from "scale expansion" to "high-end upgrading". Summary of the Invention

[0012] The technical problem this invention aims to solve is to provide a method for preparing high-sphericity nano-zirconia powder. This method utilizes a hypergravity environment to enhance mass transfer efficiency, enabling rapid and uniform mixing of zirconium salts, rare earth salts, and precipitants in a rotating bed reactor. This avoids particle agglomeration caused by localized over-concentration in traditional processes. Furthermore, it controls grain formation by regulating the feed flow rate, and subsequent aging treatment promotes ordered crystal growth. The resulting zirconia powder exhibits a monodisperse distribution with a particle size range (D50) from 0.02 to 0.2 μm, a particle sphericity ≥80%, and a narrow particle size distribution. This method is simple, low-cost, energy-efficient, and produces stable batch quality, significantly enhancing the product's application performance and scope.

[0013] To solve the first technical problem mentioned above, the technical solution adopted by the present invention is as follows: : A method for preparing highly spherical nano-zirconia powder includes the following steps: 1) Weigh out the precipitant and dissolve it in deionized water to obtain solution A. Separately weigh out the zirconium salt and rare earth salt mixture and dissolve it in deionized water to obtain solution B. 2) Add solution A and solution B to the hypergravity reactor, and adjust the reaction temperature and rotation speed in the hypergravity reactor. After mixing and precipitating, the precursor solution is obtained. 3) The precursor solution is aged, filtered, and washed to obtain the precursor; 4) The precursor was calcined to obtain highly spherical nano-zirconia powder.

[0014] Preferably, in step 1), the precipitant is one or more of ammonia, sodium hydroxide, potassium hydroxide, lithium hydroxide, sodium carbonate, potassium carbonate, and sodium bicarbonate; the zirconium salt is one or more of zirconium oxychloride, zirconium nitrate, zirconium chloride, zirconium acetate, basic zirconium carbonate, and their hydrates; and the rare earth salt is one or more of dysprosium nitrate, europium nitrate, yttrium nitrate, ytterbium nitrate, erbium nitrate, cerium nitrate, lanthanum nitrate, dysprosium chloride, europium chloride, yttrium chloride, ytterbium chloride, erbium chloride, cerium chloride, lanthanum chloride, magnesium chloride, hafnium chloride, and their hydrates.

[0015] Preferably, in step 1), the concentration of the precipitant in solution A is 0.1-3 mol / L; the concentration of the zirconium solution in solution B is 0.1-2 mol / L, and the amount of rare earth salt added is 0.1-10 mol / L; more preferably, the concentration of the precipitant in solution A is 0.5-2.5 mol / L; the concentration of the zirconium solution in solution B is 0.2-1.5 mol / L, and the amount of rare earth salt added is 3-8 mol / L.

[0016] Preferably, in step 2), the feed flow rate of liquid A is 100-1500 mL / min, the feed flow rate of liquid B is 100-1500 mL / min, and the feed flow rate ratio of liquid A to liquid B is 10:1-1:5; more preferably, the feed flow rate of liquid A is 500-1500 mL / min, the feed flow rate of liquid B is 500-1500 mL / min, and the feed flow rate ratio of liquid A to liquid B is 5:1-1:1.

[0017] Preferably, in step 2), the reaction temperature is 20-100 ℃ and the rotation speed of the hypergravity reactor is 100-3000 rpm; more preferably, the reaction temperature is 40-80 ℃ and the rotation speed of the hypergravity reactor is 1000-3000 rpm.

[0018] Preferably, in step 3), the aging temperature is 25-100 ℃ and the aging time is 0.5-12 h; more preferably, the aging temperature is 40-80 ℃ and the aging time is 2-10 h.

[0019] Preferably, in step 3), the solvent used for washing is water and ethanol, and the number of washing cycles is 2-5.

[0020] Preferably, in step 4), the calcination temperature is 400-1000 ℃ and the calcination time is 0.5-4 h; more preferably, the calcination temperature is 600-800 ℃ and the calcination time is 1-3 h.

[0021] Any range described in this invention includes the endpoint, any value between the endpoints, and any subrange consisting of the endpoint or any value between the endpoints.

[0022] Unless otherwise specified, all raw materials used in this invention can be obtained commercially, and the equipment used in this invention can be conventional equipment in the relevant field or refer to existing technology in the relevant field.

[0023] Compared with the prior art, the present invention has the following beneficial effects.

[0024] 1) Prepared using supergravity technology, the liquid inlet volume is more than 1,000 times that of traditional reactors, while the mass transfer efficiency is greatly enhanced, which greatly improves product quality and can meet the scale requirements of industrial production.

[0025] 2) The nano-zirconia powder prepared by this invention has achieved monodisperse distribution through hypergravity technology, with a particle size range D50 from 0.02-0.2 μm, particle sphericity ≥80%, and narrow particle size distribution.

[0026] 3) The nano-zirconia powder prepared by this invention is suitable for the formulation of zirconia slurry for dental 3D printing. With high sphericity and good dispersibility, the slurry has low viscosity and good fluidity, and has good mechanical and optical properties after printing and sintering. Attached Figure Description

[0027] The specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings. Figure 1 This is a process technology roadmap for the present invention; Figure 2 This is a transmission electron microscope image of the nano-zirconia prepared in Example 1 of the present invention; Figure 3 The image shows the XRD pattern of the nano-zirconia prepared in Example 1 of this invention. Figure 4 This is a particle size distribution diagram of the nano-zirconia prepared in Example 1 of the present invention. Figure 5 This is a transmission electron microscope image of the nano-zirconia prepared in Example 2 of the present invention; Figure 6 This is a transmission electron microscope image of the nano-zirconia prepared in Example 3 of the present invention; Figure 7 This is a scanning electron microscope image of the nano-zirconia prepared in Example 4 of the present invention; Figure 8 This is a transmission electron microscope image of the nano-zirconia prepared in Comparative Example 1 of this invention. Figure 9 This is a transmission electron microscope image of the nano-zirconia prepared in Comparative Example 2 of this invention; Figure 10 This is a transmission electron microscope image of the nano-zirconia prepared in Comparative Example 3 of this invention. Figure 11 This is a transmission electron microscope (TEM) image of the nano-zirconia prepared in Comparative Example 4 of this invention. Detailed Implementation

[0028] To more clearly illustrate the present invention, the following description, in conjunction with preferred embodiments, further clarifies the invention. Those skilled in the art should understand that the specific descriptions below are illustrative rather than restrictive, and should not be construed as limiting the scope of protection of the present invention.

[0029] See Figure 1 As shown, as one aspect of the present invention, a method for preparing highly spherical nano-zirconia powder includes the following steps: 1) Weigh out the precipitant and dissolve it in deionized water to obtain solution A. Separately weigh out the zirconium salt and rare earth salt mixture and dissolve it in deionized water to obtain solution B. 2) Add solution A and solution B to the hypergravity reactor, and adjust the reaction temperature and rotation speed in the hypergravity reactor. After mixing and precipitating, the precursor solution is obtained. 3) The precursor solution is aged, filtered, and washed to obtain the precursor; 4) The precursor was calcined to obtain highly spherical nano-zirconia powder.

[0030] According to certain embodiments of the present invention, in step 1), the precipitant is one or more of ammonia, sodium hydroxide, potassium hydroxide, lithium hydroxide, sodium carbonate, potassium carbonate, and sodium bicarbonate; the zirconium salt is one or more of zirconium oxychloride, zirconium nitrate, zirconium chloride, zirconium acetate, basic zirconium carbonate, and their hydrates; the rare earth salt is one or more of dysprosium nitrate, europium nitrate, yttrium nitrate, ytterbium nitrate, erbium nitrate, cerium nitrate, lanthanum nitrate, dysprosium chloride, europium chloride, yttrium chloride, ytterbium chloride, erbium chloride, cerium chloride, lanthanum chloride, magnesium chloride, hafnium chloride, and their hydrates.

[0031] According to certain embodiments of the present invention, in step 1), the concentration of the precipitant in solution A is 0.1-3 mol / L; the concentration of the zirconium solution in solution B is 0.1-2 mol / L, and the amount of rare earth salt added is 0.1-10 mol / L; more preferably, the concentration of the precipitant in solution A is 0.5-2.5 mol / L; the concentration of the zirconium solution in solution B is 0.2-1.5 mol / L, and the amount of rare earth salt added is 3-8 mol / L.

[0032] According to certain embodiments of the present invention, in step 2), the feed flow rate of liquid A is 100-1500 mL / min, the feed flow rate of liquid B is 100-1500 mL / min, and the feed flow rate ratio of liquid A to liquid B is 10:1-1:5; more preferably, the feed flow rate of liquid A is 500-1500 mL / min, the feed flow rate of liquid B is 500-1500 mL / min, and the feed flow rate ratio of liquid A to liquid B is 5:1-1:1.

[0033] According to some embodiments of the present invention, in step 2), the reaction temperature is 20-100 ℃ and the rotation speed of the hypergravity reactor is 100-3000 rpm; more preferably, the reaction temperature is 40-80 ℃ and the rotation speed of the hypergravity reactor is 1000-3000 rpm.

[0034] According to some embodiments of the present invention, in step 3), the aging temperature is 25-100 °C and the aging time is 0.5-12 h; more preferably, the aging temperature is 40-80 °C and the aging time is 2-10 h.

[0035] According to some embodiments of the present invention, in step 3), the solvent used for washing is water and ethanol, and the number of washing cycles is 2-5.

[0036] According to some embodiments of the present invention, in step 4), the calcination temperature is 400-1000 °C and the calcination time is 0.5-4 h; more preferably, the calcination temperature is 600-800 °C and the calcination time is 1-3 h. Example 1

[0037] A method for preparing highly spherical nano-zirconia powder includes the following steps: 1) Weigh a certain amount of sodium hydroxide to prepare a solution A with a concentration of 2 mol / L. Separately weigh a certain amount of zirconium oxychloride and yttrium nitrate to prepare a solution B with a total concentration of 0.5 mol / L, wherein the doping amount of yttrium nitrate is 4 mol%. 2) Turn on the hypergravity reactor, set the rotation speed to 1000 rpm, and control the temperature to 35 ℃. Then, feed solutions A and B into the hypergravity reactor at feed rates of 500 mL / min and 100 mL / min, respectively, mix and precipitate to obtain the precursor solution. 3) After aging the precursor solution at 40 °C for 6 h, wash and filter it twice with deionized water, and then wash and filter it twice with ethanol to finally obtain the precursor. 4) The precursor was calcined at 700 °C for 2 h to obtain nano-zirconia powder.

[0038] Figure 2 The image shows a transmission electron microscope (TEM) image of the nano-zirconia prepared in Example 1 of the present invention. The image shows that the sphericity of the zirconia particles is ≥94%, and the average particle size is about 20 nm.

[0039] Figure 3 The XRD pattern of the nano-zirconia prepared in Example 1 of the present invention is shown. Analysis of the spectrum shows that the tetragonal phase zirconia (t-ZrO2) accounts for 100%.

[0040] Figure 4 The particle size distribution diagram of the nano-zirconia prepared in Example 1 of the present invention is shown. It can be seen from the diagram that the zirconia powder is monodisperse and has a narrow particle size distribution. Example 2

[0041] Repeat Example 1, except that: a certain amount of potassium carbonate was weighed to prepare a 1 mol / L solution A, and a certain amount of zirconium acetate and yttrium nitrate were weighed to prepare a 0.7 mol / L solution B, wherein the yttrium nitrate doping amount was 8 mol%. The hypergravity reactor was turned on, the rotation speed was set to 1500 rpm, and the temperature was controlled at 50 °C. Solutions A and B were then fed into the hypergravity reactor at feed rates of 500 mL / min and 200 mL / min, respectively, to mix and precipitate, obtaining the precursor solution. The precursor solution was aged at 80 °C for 0.5 h, washed and filtered once with deionized water, and then washed and filtered twice with ethanol to finally obtain the precursor. The remaining steps and conditions were the same as in Example 1.

[0042] Figure 5 The image shows a transmission electron microscope (TEM) image of the nano-zirconia prepared in Example 2 of the present invention. As can be seen from the image, the sphericity of the zirconia particles is ≥90%, but they are severely agglomerated, with an average particle size of about 20 nm. Example 3

[0043] Repeat Example 1, except that: a certain amount of ammonia solution was weighed to prepare solution A with a concentration of 3 mol / L, and a certain amount of zirconium oxychloride and yttrium chloride were weighed to prepare solution B with a total concentration of 1 mol / L, wherein the doping amount of yttrium chloride was 8 mol%. The hypergravity reactor was turned on, the rotation speed was set to 500 rpm, and the temperature was controlled at 50 °C. Then, solutions A and B were fed into the hypergravity reactor at feed rates of 200 mL / min and 500 mL / min, respectively, to mix and precipitate, obtaining the precursor solution. The precursor solution was aged at 80 °C for 1 h, washed and filtered twice with deionized water, and then washed and filtered twice with ethanol to finally obtain the precursor. The remaining steps and conditions were the same as in Example 1.

[0044] Figure 6 The image shows a transmission electron microscope (TEM) image of the nano-zirconia prepared in Example 3 of the present invention. The image shows that the sphericity of the zirconia particles is ≥80%, and the average particle size is about 20 nm. Example 4

[0045] Repeat Example 1, except that: a certain amount of sodium bicarbonate solution was weighed to prepare solution A with a concentration of 2.5 mol / L, and a certain amount of zirconium oxychloride and zirconium oxychloride octahydrate were weighed to prepare solution B with a total concentration of 1 mol / L, wherein the doping amount of yttrium chloride was 5 mol%. The hypergravity reactor was turned on, the rotation speed was set to 1500 rpm, and the temperature was controlled at 80℃. Then, solutions A and B were fed into the hypergravity reactor at feed rates of 1000 mL / min and 500 mL / min, respectively, to mix and precipitate, obtaining the precursor solution. The precursor solution was aged at 80℃ for 5 h, washed and filtered twice with deionized water, and then washed and filtered twice with ethanol to finally obtain the precursor. The remaining steps and conditions were the same as in Example 1.

[0046] Figure 7 The image shows a scanning electron microscope (SEM) image of the nano-zirconia prepared in Example 4 of the present invention. The image shows that the sphericity of the zirconia particles is ≥85%, and the average particle size is about 40 nm. Comparative Example 1

[0047] Repeat Example 1, except that instead of using a supergravity reactor to mix and precipitate liquids A and B, a conventional reaction vessel is used for mixing and precipitation, while the other steps are the same.

[0048] Figure 8 The image shows a transmission electron microscope (TEM) image of the nano-zirconia prepared in Comparative Example 1 of the present invention. As can be seen from the image, the zirconia powder prepared by the conventional reaction vessel with high gravity technology has a sphericity of ≤70%, severe agglomeration, and a large average particle size (approximately 30 nm). Comparative Example 2

[0049] Example 1 was repeated, except that the rotation speed of the hypergravity reactor was set to 500 rpm and the temperature was controlled at 50°C. Then, solutions A and B were fed into the hypergravity reactor at feed rates of 100 mL / min and 200 mL / min, respectively, to mix and precipitate, thus obtaining the precursor solution. The remaining steps and conditions were the same as in Example 1.

[0050] Figure 9 The image shows a transmission electron microscope (TEM) image of the nano-zirconia prepared in Comparative Example 2 of this invention. As can be seen from the image, most of the zirconia particles are irregularly square, with a sphericity of ≤75% and an average particle size of about 25 nm.

[0051] This shows that the sphericity of zirconia was significantly reduced due to the change in hypergravity parameters. Comparative Example 3

[0052] The procedure was repeated in Example 1, except that: a certain amount of ammonium bicarbonate was weighed and prepared into a 3 mol / L solution A, and a certain amount of zirconium nitrate and cerium nitrate were weighed and prepared into a 0.2 mol / L solution B, wherein the doping amount of cerium nitrate was 10 mol%. The hypergravity reactor was turned on, the rotation speed was set to 1500 rpm, and the temperature was controlled at 80 °C. Solutions A and B were then fed into the hypergravity reactor at feed rates of 1000 mL / min and 500 mL / min, respectively, to mix and precipitate, thus obtaining the precursor solution. The precursor solution was aged at 80 °C for 5 h, washed and filtered twice with deionized water, and then washed and filtered twice with ethanol to finally obtain the precursor. The remaining steps and conditions were the same as in Example 1.

[0053] Figure 10 The image shows a transmission electron microscope (TEM) image of the nano-zirconia prepared in Comparative Example 3 of this invention. The image shows that the zirconia particles are irregularly square with a sphericity of ≤77%, indicating severe agglomeration and an average particle size of about 30 nm.

[0054] It is evident that changes in the precipitant, zirconium salt, and hypergravity parameters led to a significant decrease in the sphericity and a deterioration in the dispersibility of zirconium oxide. Comparative Example 4

[0055] Repeat Example 1, except that: a certain amount of ammonia solution was weighed to prepare solution A with a concentration of 1.5 mol / L, and a certain amount of zirconium oxychloride and yttrium nitrate were weighed to prepare solution B with a total concentration of 0.5 mol / L, wherein the doping amount of yttrium nitrate was 4 mol%. The hypergravity reactor was turned on, the rotation speed was set to 3000 rpm, and the temperature was controlled at 50 °C. Solutions A and B were then fed into the hypergravity reactor at feed rates of 100 mL / min and 200 mL / min, respectively, to mix and precipitate, thus obtaining the precursor solution. The precursor solution was aged at 60 °C for 3 h, washed and filtered twice with deionized water, and then washed and filtered twice with ethanol to finally obtain the precursor. The remaining steps and conditions were the same as in Example 1.

[0056] Figure 11 The image shows a transmission electron microscope (TEM) image of the nano-zirconia prepared in Comparative Example 4 of this invention. The image shows that the zirconia particles are irregularly square with a sphericity of ≤78% and an average particle size of about 20 nm.

[0057] This shows that the sphericity of zirconia was significantly reduced due to changes in the hypergravity parameters and subsequent aging treatments.

[0058] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art can make other variations or modifications based on the above description. It is impossible to exhaustively list all embodiments here. All obvious variations or modifications derived from the technical solutions of the present invention are still within the protection scope of the present invention.

Claims

1. A method for preparing a high-sphericity nano-zirconia powder, characterized in that, The method comprises the following steps: 1) A solution is prepared by weighing a precipitant and dissolving it in deionized water, and a B solution is prepared by weighing a zirconium salt and a rare earth salt and dissolving them in deionized water; 2) The A solution and the B solution are added to a high gravity reactor, and the reaction temperature and rotation speed in the high gravity reactor are adjusted, and a precursor solution is obtained after mixing and precipitation; 3) The precursor solution is aged, filtered and washed to obtain a precursor; 4) The precursor is calcined to obtain a high-sphericity nano-zirconia powder.

2. The method for preparing high sphericity nano-zirconia powder according to claim 1, characterized in that: In step 1), the precipitant is one or more of ammonia, sodium hydroxide, potassium hydroxide, lithium hydroxide, sodium carbonate, potassium carbonate, sodium bicarbonate; the zirconium salt is one or more of zirconium oxychloride, zirconium nitrate, zirconium chloride, zirconium acetate, basic zirconium carbonate and hydrates thereof; and the rare earth salt is one or more of dysprosium nitrate, europium nitrate, yttrium nitrate, ytterbium nitrate, erbium nitrate, cerium nitrate, lanthanum nitrate, dysprosium chloride, europium chloride, yttrium chloride, ytterbium chloride, erbium chloride, cerium chloride, lanthanum chloride, magnesium chloride, hafnium chloride and hydrates thereof.

3. The method for preparing high sphericity nano-zirconia powder according to claim 1, characterized in that: In step 1), the concentration of the precipitant in the A solution is 0.1-3 mol / L; the concentration of the zirconium solution in the B solution is 0.1-2 mol / L, and the addition amount of the rare earth salt is 0.1-10 mol / L; more preferably, the concentration of the precipitant in the A solution is 0.5-2.5 mol / L; the concentration of the zirconium solution in the B solution is 0.2-1.5 mol / L, and the addition amount of the rare earth salt is 3-8 mol / L.

4. The method for preparing high-sphericity nano-zirconia powder according to claim 1, characterized in that: In step 2), the feeding flow rate of the A solution is 100-1500 mL / min, the feeding flow rate of the B solution is 100-1500 mL / min, and the ratio of the feeding flow rates of the A solution and the B solution is 10:1-1:5; more preferably, the feeding flow rate of the A solution is 500-1500 mL / min, the feeding flow rate of the B solution is 500-1500 mL / min, and the ratio of the feeding flow rates of the A solution and the B solution is 5:1-1:

1.

5. The method for preparing high sphericity nano-zirconia powder according to claim 1, characterized in that: In step 2), the reaction temperature is 20-100 ℃, and the rotation speed of the high gravity reactor is 100-3000 rpm; more preferably, the reaction temperature is 40-80 ℃, and the rotation speed of the high gravity reactor is 1000-3000 rpm.

6. The method for preparing high sphericity nano-zirconia powder according to claim 1, characterized in that: In step 3), the aging temperature is 25-100 ℃, and the aging time is 0.5-12 h; more preferably, the aging temperature is 40-80 ℃, and the aging time is 2-10 h.

7. The method for preparing high sphericity nano-zirconia powder according to claim 1, characterized in that: In step 3), the solvent used for washing is water and ethanol, and the washing is performed for 2-5 times.

8. The method for preparing high sphericity nano-zirconia powder according to claim 1, characterized in that: In step 4), the calcination temperature is 400-1000 ℃, and the calcination time is 0.5-4 h; more preferably, the calcination temperature is 600-800 ℃, and the calcination time is 1-3 h.

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