Process for preparing rare earth polishing powder by temperature-controlled precipitation

Abstract

The application discloses a kind of process for preparing rare earth polishing powder by temperature control precipitation method, which comprises the following steps: step one, solvent preparation;Step two, temperature control precipitation reaction;Step three, cleaning;Step four, crushing;Step five, calcination.The process of the present application can control particle growth and inhibit particle agglomeration by controlling the initial temperature and temperature rise rate during the precipitation reaction using the temperature control precipitation method, and can obtain rare earth polishing powder with good uniformity and uniform particle size distribution after crushing and calcination.No aging treatment is needed after the precipitation reaction to adjust the apparent morphology of the precursor, which can effectively shorten the preparation process and is suitable for the field of micro-nano powder synthesis technology.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of micro-nano powder synthesis, and particularly relates to a process for preparing rare earth polishing powder by a temperature-controlled precipitation method. BACKGROUND

[0002] Chemical mechanical polishing (CMP) is a technology for realizing ultra-precision mechanical processing in industry, and is widely used in the fields of precision optics, aerospace and information technology, because it can perfectly balance global planarization, material surface defects and use reliability. However, with the continuous improvement of product standards in the field of high-precision polishing, the requirements for the particle uniformity of rare earth polishing powder, especially the avoidance of large particles, are increasing year by year, which has become an important influencing factor for evaluating the quality of polishing powder.

[0003] The main methods for preparing rare earth polishing powder in industry are precipitation method, hydrothermal method, etc. Among them, the hydrothermal method can obtain near-spherical particles of different sizes through process control, but it needs high-temperature and high-pressure environment in the preparation, which has high production cost and low efficiency. Compared with the hydrothermal method, the precipitation method, as the most widely used method for preparing polishing powder, has the advantages of high production efficiency, low process cost and simple equipment requirement.

[0004] For example, the Chinese invention patent "Ultrafine and spheroidized rare earth polishing powder and its preparation process" (publication number CN101284983B) prepares ultrafine and spheroidized rare earth polishing powder by using ammonia water precipitation method. After precipitation, high-temperature aging is needed, and then ball milling or air flow milling is carried out to break and screen, so as to obtain rare earth polishing powder. The Chinese invention patent "Preparation method of micrometer cerium oxide with large specific surface area" (publication number CN106277020A) adds oxalic acid or sodium hydroxide and anionic surfactant to a rare earth salt solution, obtains a precursor after precipitation and aging, and obtains cerium oxide after adding a coupling agent and calcining. However, the above-mentioned precipitation method uses fixed temperature holding reaction, and needs aging after the completion of the precipitation reaction to optimize the product morphology. There are problems of long process flow of precipitation + aging and difficult control of product morphology. SUMMARY

[0005] The present application aims to overcome the shortcomings of the prior art, and provides a process for preparing rare earth polishing powder by a temperature-controlled precipitation method. This method controls the temperature during the precipitation reaction, does not need aging, and can obtain polishing powder with good uniformity and narrow particle size distribution after breaking and calcining, solving the problems of long preparation process and difficult control of product morphology in the prior art for preparing rare earth polishing powder.

[0006] To achieve the above-mentioned purpose, the technical solution adopted by the present application is: a process for preparing rare earth polishing powder by a temperature-controlled precipitation method, characterized in that the process comprises the following steps:

[0007] Step one, solvent preparation: mix rare earth salt, dispersant and water uniformly to obtain solvent A; mix alkaline precipitator, oxidant and water uniformly to obtain solvent B;

[0008] Step two, temperature-controlled precipitation reaction: mix solvent A and solvent B obtained in step one in a heating environment and carry out precipitation reaction to obtain a precursor;

[0009] Step three, cleaning: add the precursor obtained in step two into deionized water to carry out ultrasonic cleaning and centrifugation;

[0010] Step four, crushing: dry and crush the precursor after centrifugation in step three to obtain a precursor powder;

[0011] Step five, calcination: carry out calcination on the precursor powder obtained in step four to obtain rare earth polishing powder.

[0012] The application can raise the valence of rare earth elements by adding oxidant in solvent B, and can make the precipitation product change to rare earth oxide by combining with the temperature-controlled precipitation reaction, so as to realize preliminary crystallization, and can strengthen crystallization and improve the crystallinity of rare earth polishing powder by subsequent calcination; when the rare earth salt includes Ce salt, the oxidant can oxidize the rare earth to Ce 4+ , the precipitation product changes to CeO2 to realize preliminary crystallization, and the product is strengthened by calcination, while the product precipitated by the existing technology at a fixed temperature is generally amorphous precursor, which changes to alkaline carbonate such as Ce2(CO3)3·8H2O, [Nd, La, Ca][CO3][OH][H2O] after aging, and the product morphology and particle size uniformity are poor after calcination.

[0013] The process for preparing rare earth polishing powder by the above-mentioned temperature-controlled precipitation method, characterized in that the concentration of rare earth salt in solvent A in step one is 0.1 mol / L to 1 mol / L, and the rare earth salt is one or more than two of water-soluble rare earth salt and its hydrate.

[0014] The process for preparing rare earth polishing powder by the above-mentioned temperature-controlled precipitation method, characterized in that the mass concentration of dispersant in solvent A in step one is 0.1% to 4%, and the dispersant is one of polyethylene glycol, polyvinylpyrrolidone and hydroxypropyl cellulose.

[0015] The process for preparing rare earth polishing powder by the above-mentioned temperature-controlled precipitation method, characterized in that the concentration of alkaline precipitator in solvent B in step one is 1.5 mol / L to 5.5 mol / L, and the alkaline precipitator is one or more than two of ammonium bicarbonate, ammonia water, sodium bicarbonate and urea.

[0016] The process for preparing the rare earth polishing powder by the temperature-controlled precipitation method has the characteristics that the concentration of the oxidizing agent in the solvent B in step one is 0.1-2 mol / L, and the oxidizing agent is hydrogen peroxide.

[0017] The process for preparing the rare earth polishing powder by the temperature-controlled precipitation method has the characteristics that the mixing process in step two is that the solvent B is added into the solvent A at a flow rate of 1-20 mL / min by using a micro-injection pump or a peristaltic pump, and stirring is carried out during the mixing process; the temperature rising system of the temperature rising environment is that the initial temperature is controlled to be below 40 DEG C, and then the temperature is raised to 65-95 DEG C at a rate of 0.5-2 DEG C / min, and then the temperature is kept constant, and the temperature difference between the temperature keeping temperature and the initial temperature is not less than 45 DEG C; and the precipitation reaction time is not more than 90 min.

[0018] The process for preparing the rare earth polishing powder by the temperature-controlled precipitation method has the characteristics that the concentration of the oxidizing agent in the solvent B in step one is 0.1-2 mol / L, and the oxidizing agent is hydrogen peroxide.

[0019] The process for preparing the rare earth polishing powder by the temperature-controlled precipitation method has the characteristics that the mixing process in step two is that the solvent B is added into the solvent A at a flow rate of 1-20 mL / min by using a micro-injection pump or a peristaltic pump, and stirring is carried out during the mixing process; the temperature rising system of the temperature rising environment is that the initial temperature is controlled to be below 40 DEG C, and then the temperature is raised to 65-95 DEG C at a rate of 0.5-2 DEG C / min, and then the temperature is kept constant, and the temperature difference between the temperature keeping temperature and the initial temperature is not less than 45 DEG C; and the precipitation reaction time is not more than 90 min.

[0020] The process for preparing the rare earth polishing powder by the temperature-controlled precipitation method has the characteristics that the mixing process in step two is that the solvent B is added into the solvent A at a flow rate of 1-20 mL / min by using a micro-injection pump or a peristaltic pump, and stirring is carried out during the mixing process; the temperature rising system of the temperature rising environment is that the initial temperature is controlled to be below 40 DEG C, and then the temperature is raised to 65-95 DEG C at a rate of 0.5-2 DEG C / min, and then the temperature is kept constant, and the temperature difference between the temperature keeping temperature and the initial temperature is not less than 45 DEG C; and the precipitation reaction time is not more than 90 min.

[0021] The process for preparing the rare earth polishing powder by the temperature-controlled precipitation method has the characteristics that the mixing process in step two is that the solvent B is added into the solvent A at a flow rate of 1-20 mL / min by using a micro-injection pump or a peristaltic pump, and stirring is carried out during the mixing process; the temperature rising system of the temperature rising environment is that the initial temperature is controlled to be below 40 DEG C, and then the temperature is raised to 65-95 DEG C at a rate of 0.5-2 DEG C / min, and then the temperature is kept constant, and the temperature difference between the temperature keeping temperature and the initial temperature is not less than 45 DEG C; and the precipitation reaction time is not more than 90 min.

[0022] The process for preparing the rare earth polishing powder by the temperature-controlled precipitation method has the characteristics that the mixing process in step two is that the solvent B is added into the solvent A at a flow rate of 1-20 mL / min by using a micro-injection pump or a peristaltic pump, and stirring is carried out during the mixing process; the temperature rising system of the temperature rising environment is that the initial temperature is controlled to be below 40 DEG C, and then the temperature is raised to 65-95 DEG C at a rate of 0.5-2 DEG C / min, and then the temperature is kept constant, and the temperature difference between the temperature keeping temperature and the initial temperature is not less than 45 DEG C; and the precipitation reaction time is not more than 90 min.

[0023] The process for preparing the rare earth polishing powder by the temperature-controlled precipitation method has the characteristics that the mixing process in step two is that the solvent B is added into the solvent A at a flow rate of 1-20 mL / min by using a micro-injection pump or a peristaltic pump, and stirring is carried out during the mixing process; the temperature rising system of the temperature rising environment is that the initial temperature is controlled to be below 40 DEG C, and then the temperature is raised to 65-95 DEG C at a rate of 0.5-2 DEG C / min, and then the temperature is kept constant, and the temperature difference between the temperature keeping temperature and the initial temperature is not less than 45 DEG C; and the precipitation reaction time is not more than 90 min.

[0024] Compared with the prior art, the present application has the following advantages:

[0025] 1、The present application can control the particle growth and inhibit the particle agglomeration by controlling the temperature rise in the precipitation reaction process through the temperature-controlled precipitation method, and can obtain the polishing powder with good uniformity and uniform particle size distribution after crushing and calcination.

[0026] 2、The preparation process of the present application does not need to be aged after the precipitation reaction to adjust the apparent morphology of the precursor, can effectively shorten the preparation process flow of the rare earth polishing powder, and further reduce the energy consumption and improve the production efficiency.

[0027] 3、The present application can increase the valence of rare earth elements by adding an oxidizing agent in the solvent B, convert the precipitation product into rare earth oxide, realize the preliminary crystallization, and strengthen the crystallization after calcination to improve the crystallinity and particle size uniformity of the rare earth polishing powder; avoid the use of the precipitation + aging process in the prior art, precipitate at a fixed temperature, and then control the morphology by adjusting the aging temperature and time, which leads to excessive growth of the crystal grains and is not conducive to controlling the morphology and particle size uniformity of the rare earth polishing powder.

[0028] The technical solutions of the present application will be further described in detail below through the drawings and examples. BRIEF DESCRIPTION OF DRAWINGS

[0029] Figure 1 The XRD test result graph of the rare earth polishing powder obtained in Example 1 of the present application.

[0030] Figure 2 The scanning electron microscope graph of the rare earth polishing powder obtained in Example 1 of the present application.

[0031] Figure 3 The scanning electron microscope graph of the rare earth polishing powder obtained in Comparative Example 1 of the present application.

[0032] Figure 4 The scanning electron microscope graph of the rare earth polishing powder obtained in Example 2 of the present application. DETAILED DESCRIPTION

[0033] Example 1

[0034] The process of the present embodiment includes the following steps:

[0035] Step one, solvent preparation: 7g cerium nitrate hexahydrate, 3g lanthanum nitrate hexahydrate and 1g polyethylene glycol are uniformly mixed with 50mL deionized water to obtain solvent A; 4g ammonium bicarbonate, 2mL ammonia water and 5mL hydrogen peroxide are uniformly mixed with 50mL deionized water to obtain solvent B;

[0036] Step 2, Temperature-Controlled Precipitation Reaction: Solvent A obtained in Step 1 is preheated in a water bath at 40°C. Solvent B is added dropwise to solvent A at a flow rate of 1 mL / min using a micro-injection pump. During the addition, the water bath is heated to 85°C at a rate of 1°C / min and then kept at that temperature to obtain the precursor. The temperature-controlled precipitation reaction is carried out with stirring at 600 r / min, and the precipitation reaction time is 50 min.

[0037] Step 3, Cleaning: Cool the precursor obtained in Step 2 to below 50°C, and then add it to deionized water for ultrasonic cleaning and centrifugation;

[0038] Step 4, Crushing: Place the precursor after centrifugation in step 3 in an oven and dry it at 60°C. After grinding, obtain precursor powder.

[0039] Step 5, calcination: Place the precursor powder obtained in step 4 into a muffle furnace and calcine it at 600℃ to obtain rare earth polishing powder.

[0040] XRD analysis was performed on the rare earth polishing powder obtained in this embodiment, and the results are as follows: Figure 1 As shown, the main phase of this rare earth polishing powder is (Ce, La)O2; microscopic analysis of the rare earth polishing powder obtained in this embodiment is as follows: Figure 2 As shown, the rare earth polishing powder consists of submicron particles with uniform particle size distribution and no large particle agglomeration.

[0041] The rare earth polishing powder obtained in this embodiment was used to prepare a polishing slurry containing 0.5% rare earth polishing powder by mass. The slurry was used to polish K9 glass, and the surface removal rate (MRR) of the polishing slurry was measured to be 500 nm / min. The surface roughness (Ra) of the polishing slurry after polishing was 0.48 nm.

[0042] Comparative Example 1

[0043] The difference between this comparative example and Example 1 is that the temperature of the precipitation reaction in step two is a constant 75°C.

[0044] Microscopic analysis was performed on the rare earth polishing powder obtained in this comparative example, such as... Figure 3 As shown, the rare earth polishing powder exhibits a distinct flake-like morphology with varying sizes, and some particles have a particle size greater than 10 μm, making it unsuitable for direct use as polishing powder. This indicates that in Example 1, the precipitation reaction under elevated temperature conditions can effectively reduce the particle size of the rare earth polishing powder, optimize its morphology, and improve its particle size uniformity.

[0045] Example 2

[0046] The process in this embodiment includes the following steps:

[0047] Step 1, Solvent preparation: Mix 13g cerium nitrate hexahydrate, 3g lanthanum nitrate hexahydrate, and 1.5g polyethylene glycol with 50mL deionized water to obtain solvent A; mix 6g ammonium bicarbonate, 3ml ammonia water, 6mL hydrogen peroxide, and 50mL deionized water to obtain solvent B.

[0048] Step 2, Temperature-Controlled Precipitation Reaction: Solvent A obtained in Step 1 is preheated in a water bath at 20°C. Solvent B is added dropwise to solvent A at a flow rate of 1 mL / min using a micro-injection pump. During the dropwise addition, the water bath is heated to 65°C at a rate of 1°C / min and then kept at that temperature to obtain the precursor. The temperature-controlled precipitation reaction is carried out with stirring at 1000 r / min, and the precipitation reaction time is 50 min.

[0049] Step 3, Cleaning: Cool the precursor obtained in Step 2 to below 50°C, and then add it to deionized water for ultrasonic cleaning and centrifugation;

[0050] Step 4, Crushing: The precursor obtained from centrifugation in Step 3 is freeze-dried to obtain precursor powder.

[0051] Step 5, calcination: Place the precursor powder obtained in step 4 into a muffle furnace and calcine it at 700℃ to obtain rare earth polishing powder.

[0052] Microscopic analysis was performed on the rare earth polishing powder obtained in this embodiment, such as... Figure 4 As shown, the rare earth polishing powder consists of submicron particles with uniform particle size distribution. Compared with Example 1, the rare earth polishing powder has higher uniformity. The surface freeze-drying technology is beneficial to improving the uniformity of the particle size of the rare earth polishing powder.

[0053] The rare earth polishing powder obtained in this embodiment was used to prepare a polishing slurry containing 0.5% rare earth polishing powder by mass. The slurry was used to polish K9 glass, and the surface removal rate (MRR) of the polishing slurry was measured to be 556 nm / min. The surface roughness (Ra) of the polishing slurry after polishing was 0.34 nm.

[0054] Example 3

[0055] The process in this embodiment includes the following steps:

[0056] Step 1: Solvent preparation: Mix 5g of cerium nitrate hexahydrate, 1g of lanthanum nitrate hexahydrate and 1g of polyvinylpyrrolidone with 50mL of deionized water to obtain solvent A; mix 4g of sodium bicarbonate, 1ml of ammonia water, 3mL of hydrogen peroxide and 50mL of deionized water to obtain solvent B.

[0057] Step two, temperature control precipitation reaction: the solvent A obtained in step one is preheated in a water bath at 30°C, and solvent B is added dropwise into solvent A at a flow rate of 1 mL / min using a micro-injection pump, and the water bath is heated at a rate of 2°C / min to 95°C and then kept at this temperature during the dropwise addition process; the stirring speed during the temperature control precipitation reaction is 600 r / min, and the precipitation reaction time is 50 min;

[0058] Step three, cleaning: the precursor obtained in step two is cooled to below 50°C, then deionized water is added for ultrasonic cleaning and centrifugation;

[0059] Step four, crushing: the precursor after centrifugation in step three is placed in an oven and dried at 60°C, then ground to obtain a precursor powder;

[0060] Step five, calcination: the precursor powder obtained in step four is placed in a muffle furnace and calcined at 600°C to obtain a rare earth polishing powder.

[0061] The rare earth polishing powder obtained in this example is used to prepare a polishing liquid containing 0.5% rare earth polishing powder by mass fraction, and K9 glass is polished for testing. The surface removal rate (MRR) of the polishing liquid is 621 nm / min, and the surface roughness (Ra) of the polished polishing liquid is 0.52 nm.

[0062] Example 4

[0063] The process of this example includes the following steps:

[0064] Step one, solvent preparation: 76 g of cerium nitrate hexahydrate, 35 g of lanthanum nitrate hexahydrate, and 15 g of polyvinylpyrrolidone are mixed with 500 mL of deionized water to obtain solvent A; 80 g of ammonium bicarbonate, 30 mL of ammonia water, and 45 mL of hydrogen peroxide are mixed with deionized water to obtain 500 mL of solvent B;

[0065] Step two, temperature control precipitation reaction: the solvent A obtained in step one is preheated in a water bath at 40°C, and solvent B is added dropwise into solvent A at a flow rate of 5.5 mL / min using a peristaltic pump, and the water bath is heated at a rate of 0.5°C / min to 85°C and then kept at this temperature during the dropwise addition process; the stirring speed during the temperature control precipitation reaction is 1000 r / min; the reaction time is 90 min.

[0066] Step three, cleaning: the precursor obtained in step two is cooled to below 50°C, then deionized water is added for ultrasonic cleaning and centrifugation;

[0067] Step four, crushing: the precursor after centrifugation in step three is placed in an oven and dried at 60°C, then ground to obtain a precursor powder;

[0068] Step five, calcination: the precursor powder obtained in step four is placed in a muffle furnace and calcined at 800°C to obtain rare earth polishing powder.

[0069] The rare earth polishing powder obtained in this example is used to prepare a polishing liquid containing 0.5% of the rare earth polishing powder by mass, and K9 glass is polished for testing. The surface removal rate (MRR) of the polishing liquid is measured to be 628 nm / min, and the surface roughness (Ra) of the polishing liquid after polishing is 0.74 nm.

[0070] Example 5

[0071] The process of this example includes the following steps:

[0072] Step one, solvent preparation: 200g of cerium nitrate hexahydrate, 100g of lanthanum nitrate hexahydrate, and 30g of polyvinylpyrrolidone are mixed with 1500mL of deionized water to obtain solvent A; 200g of ammonium bicarbonate, 30ml of ammonia water, and 80ml of hydrogen peroxide are mixed with deionized water to obtain 1500mL of solvent B;

[0073] Step two, temperature-controlled precipitation reaction: the solvent A obtained in step one is preheated in a 40°C water bath, and the solvent B is added to the solvent A at a flow rate of 20mL / min using a peristaltic pump, and the water bath is heated at a rate of 1°C / min to 85°C during the addition process and then kept at this temperature; the precursor is obtained; the stirring speed during the temperature-controlled precipitation reaction is 1000r / min; the reaction time is 75min.

[0074] Step three, cleaning: the precursor obtained in step two is cooled to below 50°C, then added to deionized water for ultrasonic cleaning and centrifugation;

[0075] Step four, crushing: the precursor after centrifugation in step three is placed in an oven and dried at 60°C, then ground to obtain a precursor powder;

[0076] Step five, calcination: the precursor powder obtained in step four is placed in a muffle furnace and calcined at 1000°C to obtain rare earth polishing powder.

[0077] The rare earth polishing powder obtained in this example is used to prepare a polishing liquid containing 0.5% of the rare earth polishing powder by mass, and K9 glass is polished for testing. The surface removal rate (MRR) of the polishing liquid is measured to be 778 nm / min, and the surface roughness (Ra) of the polishing liquid after polishing is 1.02 nm.

[0078] Example 6

[0079] The process of this example includes the following steps:

[0080] Step one, solvent preparation: 2g of cerium nitrate hexahydrate and 0.05g of polyvinylpyrrolidone are mixed uniformly with 50mL of deionized water to obtain solvent A; 4g of ammonium bicarbonate, 1ml of ammonia water, 1mL of hydrogen peroxide and deionized water are mixed uniformly to 50mL to obtain solvent B;

[0081] Step two, temperature-controlled precipitation reaction: the solvent A obtained in step one is preheated in a 40℃ water bath, solvent B is added to solvent A at a flow rate of 1mL / min using a microsyringe pump, and the water bath is heated at a rate of 1℃ / min to 85℃ during the dropwise addition process and then kept at 85℃, to obtain a precursor; stirring is carried out at a speed of 600r / min during the temperature-controlled precipitation reaction, and the precipitation reaction time is 50min;

[0082] Step three, cleaning: the precursor obtained in step two is cooled to below 50℃, then added to deionized water for ultrasonic cleaning and centrifugation;

[0083] Step four, crushing: the precursor after centrifugation in step three is placed in an oven and dried at 60℃, then ground to obtain a precursor powder;

[0084] Step five, calcination: the precursor powder obtained in step four is placed in a muffle furnace and calcined at 300℃ to obtain a rare earth polishing powder.

[0085] The obtained sample is small and has not been tested for polishing.

[0086] Example 7

[0087] The process of this example includes the following steps:

[0088] Step one, solvent preparation: 11g of cerium nitrate hexahydrate, 10g of lanthanum nitrate hexahydrate and 2g of polyvinylpyrrolidone are mixed uniformly with 50mL of deionized water to obtain solvent A; 16.5g of urea, 3ml of ammonia water, 10mL of hydrogen peroxide and deionized water are mixed uniformly to 50mL to obtain solvent B;

[0089] Step two, temperature-controlled precipitation reaction: the solvent A obtained in step one is preheated in a 40℃ water bath, solvent B is added to solvent A at a flow rate of 1mL / min using a microsyringe pump, and the water bath is heated at a rate of 1℃ / min to 85℃ during the dropwise addition process and then kept at 85℃, to obtain a precursor; stirring is carried out at a speed of 600r / min during the temperature-controlled precipitation reaction, and the precipitation reaction time is 50min;

[0090] Step three, cleaning: the precursor obtained in step two is cooled to below 50℃, then added to deionized water for ultrasonic cleaning and centrifugation;

[0091] Step four, crushing: the precursor after centrifugation in step three is placed in an oven to dry at 60℃, and the precursor powder is obtained after grinding;

[0092] Step five, calcination: the precursor powder obtained in step four is placed in a muffle furnace to calcine at 700℃, and the rare earth polishing powder is obtained.

[0093] The rare earth polishing powder obtained in the example is prepared into a polishing liquid containing 0.5% of the rare earth polishing powder by mass, and K9 glass is polished for testing, and the surface removal rate (MRR) of the polishing liquid is measured to be 651 nm / min, and the surface roughness (Ra) of the polishing liquid after polishing is 0.63 nm.

[0094] The above is only a preferred embodiment of the present application, not any limitation on the present application, and any simple modification, change and equivalent structure change of the above embodiment according to the technical essence of the present application are still within the protection scope of the technical solution of the present application.

Claims

1. A process for preparing rare earth polishing powder by temperature-controlled precipitation, characterized in that, The process comprises the following steps: Step one, solvent preparation: mix rare earth salt, dispersant and water uniformly to obtain solvent A; mix alkaline precipitator, oxidant and water uniformly to obtain solvent B; the concentration of rare earth salt in the solvent A is 0.1-1 mol / L, the rare earth salt is one or more than two of water-soluble rare earth salt and its hydrate; the mass concentration of dispersant in the solvent A is 0.1-4%, the dispersant is one of polyethylene glycol, polyvinylpyrrolidone and hydroxypropyl cellulose; the concentration of alkaline precipitator in the solvent B is 1.5-5.5 mol / L, the alkaline precipitator is one or more than two of ammonium bicarbonate, ammonia, sodium bicarbonate and urea; the concentration of oxidant in the solvent B is 0.1-2 mol / L, the oxidant is hydrogen peroxide; Step two, temperature-controlled precipitation reaction: mix the solvent A and solvent B obtained in step one in a heating environment and carry out precipitation reaction to obtain a precursor; the mixing process is that the solvent B is added into the solvent A at a flow rate of 1-20 mL / min by using a micro-injection pump or peristaltic pump; stirring is carried out during the mixing process; the temperature control system of the heating environment is that the initial temperature is controlled below 40℃, then the temperature is raised to 65-95℃ at a rate of 0.5-2℃ / min and then the temperature is kept constant, the temperature difference between the temperature kept constant and the initial temperature is not less than 45℃; the time of the precipitation reaction is not more than 90 min; Step three, cleaning: the precursor obtained in step two is added into deionized water for ultrasonic cleaning and centrifugation; Step four, crushing: the precursor after centrifugation in step three is dried and crushed to obtain a precursor powder; Step five, calcination: the precursor powder obtained in step four is calcined to obtain rare earth polishing powder.

2. The process for preparing rare earth polishing powder by temperature-controlled precipitation according to claim 1, characterized in that, The precursor in step three is cooled to below 50℃ before ultrasonic cleaning and centrifugation.

3. The process for preparing rare earth polishing powder by temperature-controlled precipitation according to claim 1, characterized in that, The crushing in step four is drying and grinding or freeze-drying treatment.

4. The process for preparing rare earth polishing powder by temperature-controlled precipitation according to claim 1, characterized in that, The calcination temperature in step five is 300-1000℃.

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