Ce-based polishing slurry compounding method capable of prolonging settling time

Abstract

The invention discloses a Ce-based polishing slurry compounding method capable of prolonging settling time, and belongs to the technical field of rare earth polishing materials. Comprising the following steps: mixing cerium oxide and LaCe rare earth fluoride according to a certain proportion, adding water, and pulping; fully stirring, and carrying out ball milling after the fluorination reaction is finished; drying and dewatering the ball-milled material liquid; and then feeding the dried material from the spray dryer into a jet mill crusher for crushing and grading treatment to prepare the Ce-based rare earth polishing powder with controllable particle size. The preparation method comprises the following steps: selecting high-whiteness aluminum silicate, superfine kaolin, precipitated silicon dioxide, sodium hexametaphosphate and potassium chloride as raw materials, and compounding according to a certain proportion to obtain a compound additive; and adding the prepared compound additive into the prepared Ce-based rare earth polishing powder, and fully stirring and mixing by using a stirrer. The settling time of the Ce-based polishing slurry is prolonged, and the effective concentration and polishing stability of the polishing slurry in the using process are guaranteed, so that the polishing efficiency is improved.

Description

Technical Field

[0001] The invention relates to the technical field of rare earth polishing materials, in particular to a Ce-based polishing slurry compounding method capable of prolonging sedimentation time. Background Art

[0002] Rare earth polishing materials are widely used in many fields such as liquid crystal glass, eyeglass lenses, and photomasks due to their advantages of high polishing efficiency, good polishing quality, long life, and environmental protection. In view of the current usage of rare earth polishing materials, in addition to the polishing of crystal rhinestones, polishing applications in other fields require the rare earth polishing powder to be mixed with tap water in a certain proportion and then circulated using a slurry pump.

[0003] At present, the particle size of polishing powder for most optical glass processing is generally micron-level. In addition, the powder has a certain chemical activity, which causes the polishing powder to deposit during use. When the polishing powder abrasive particles are deposited in the polishing equipment or circulation pipeline, the solid content of the circulating slurry will be reduced, resulting in insufficient effective polishing concentration of the polishing slurry, thereby reducing the polishing speed and the processing speed. At the same time, the deposited abrasive particles cause blockage, affecting the operation of the equipment and directly affecting the polishing efficiency. In order to avoid this deposition phenomenon, it is necessary to improve the suspension performance of the polishing slurry and extend the settling time of the polishing slurry.

[0004] The Chinese invention patent with publication number CN108864948A provides a glass polishing powder, polishing liquid and a preparation method thereof. By adding a suspending agent, a dispersing agent, a leveling agent and a grinding aid, a polishing liquid with good suspension and dispersion performance, high polishing rate and excellent surface quality is prepared. The chemical components of the polishing liquid mainly include: 50-60% polishing powder, 0.5-1% suspending agent, 1-10% dispersing agent, 1-5% leveling agent, 1%-5% grinding aid and the balance of water. The amount of additives added in this patent is large, and the cost of the additives is high, which will undoubtedly increase the manufacturing cost of the rare earth polishing liquid. Summary of the invention

[0005] The purpose of the present invention is to provide a Ce-based polishing slurry compounding method that can prolong the sedimentation time in order to ensure the effective concentration and polishing stability of the polishing slurry in the actual polishing process in view of the fact that optical glass processing equipment is gradually developing towards large-scale and large-scale with the increase in market demand, so as to solve the problems raised in the above-mentioned background technology.

[0006] The technical solution adopted by the present invention is as follows:

[0007] A Ce-based polishing slurry compounding method capable of prolonging the settling time comprises the following steps:

[0008] Step 1: Preparation of Ce-based rare earth polishing powder

[0009] Cerium oxide and LaCe rare earth fluoride are mixed in a certain proportion, and then water is added to make a slurry, and the mixture is stirred sufficiently. After the fluorination reaction is completed, the mixture is put into a QX-200 ball mill for ball milling, and then the ball milled mixture is put into an LPG series high-speed centrifugal granulation spray dryer for drying and dehydration, and then the dried material from the spray dryer is put into an air flow mill crusher for crushing and grading, and finally a Ce-based rare earth polishing powder with controllable particle size is obtained;

[0010] Step 2: Additive Compounding

[0011] High white aluminum silicate, ultrafine kaolin, precipitated silica, sodium hexametaphosphate and potassium chloride are selected as raw materials and compounded in a certain proportion to obtain a compound additive;

[0012] Step 3: adding the compound additive prepared in step 2 to the Ce-based rare earth polishing powder prepared in step 1, and using a stirrer to fully stir and mix;

[0013] Step 4: Add tap water to the mixed product obtained in step 3 to prepare polishing slurry. During the beating process, a suspension densitometer is used to monitor the instantaneous density value change of the slurry, and observe whether the polishing particles that have settled partially after the slurry has been left to stand for a long time are agglomerated;

[0014] Step 5: Take the polishing slurry obtained in step 4 and use an M200 flat surface precision grinding and polishing machine and an optical 3D surface profiler to evaluate the polishing performance.

[0015] Furthermore, in step 2, the selected high white aluminum silicate is a high white aluminum silicate with a porous fluffy structure, good absorbency, high brightness, low friction and wear, and excellent suspension performance; the selected ultrafine kaolin is an ultrafine high-purity kaolin with a flaky structure, a particle size of less than 0.1 μm and good water solubility; the selected precipitated silica is precipitated silica with a network structure.

[0016] Furthermore, in step one, the solid-liquid ratio (mass-to-volume ratio) of cerium oxide, LaCe rare earth fluoride and tap water is 1:1; the proportion of fluorine element in rare earth oxide is 1% to 8%; the liquid is put into a QX-200 ball mill for ball milling to reduce the D50 of the rare earth oxide to 5 to 10 μm; the temperature of the ball milled liquid in a spray dryer is 150°C to 260°C; the controllable particle size of the dried material in the air flow mill crusher is 0.5 μm to 2.5 μm.

[0017] Furthermore, in step 2, the amount of high white aluminum silicate added is 1‰ to 3‰ of the mass fraction of the Ce-based polishing powder, the amount of ultrafine kaolin added is 1‰ to 3‰ of the mass fraction of the Ce-based polishing powder, the amount of precipitated silica added is 1‰ to 3‰ of the mass fraction of the Ce-based polishing powder, the amount of sodium hexametaphosphate added is 0.5‰ to 2.5‰ of the mass fraction of the Ce-based polishing powder, and the amount of potassium chloride added is 1‰ to 2.5‰ of the mass fraction of the Ce-based polishing powder.

[0018] Furthermore, in step three, the agitator used is a plowshare agitator, and the agitation time is not less than 30 minutes.

[0019] Furthermore, in step 4, the solid-liquid ratio (solid-liquid mass volume ratio) of the Ce-based polishing slurry is 1:7 to 1:12, that is, the solid content of the polishing slurry is 8% to 15%.

[0020] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0021] 1. The present invention compounds the additives in the Ce-based polishing powder, thereby improving the added value of the Ce-based polishing powder product, which can prolong the sedimentation time of the Ce-based polishing slurry, ensure the effective concentration and polishing stability of the polishing slurry during use, and thus improve the polishing efficiency.

[0022] 2. The compounded additive of the present invention prolongs the sedimentation time of the Ce-based polishing slurry, effectively avoids the blockage of the polishing slurry in the polishing equipment and the conveying pipeline, and alleviates the trouble of operators repeatedly cleaning the blocked pipeline.

[0023] 3. The compounded additives of the present invention prevent the Ce-based polishing slurry from becoming hardened after being left standing for a long time. During use, the user can simply start the stirrer again to stir up all the materials for continued use, thereby also improving the utilization rate of the polishing powder particles. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 is a flow chart of the present invention;

[0025] Figure 2 is a graph showing instantaneous changes in the suspension density of two Ce-based polishing slurries in Example 1 of the present invention and Comparative Example 1;

[0026] Figure 3 Surface roughness diagram of glass after polishing the glass with two Ce-based polishing slurries in Example 1 of the present invention and Comparative Example 1. DETAILED DESCRIPTION

[0027] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in combination with the drawings and specific data in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments.

[0028] Therefore, the following detailed description of the embodiments of the present invention is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0029] Example

[0030] like Figure 1 This embodiment provides a Ce-based polishing slurry compounding method that can extend the sedimentation time, comprising the following steps:

[0031] Step 1: Preparation of Ce-based rare earth polishing powder

[0032] Cerium oxide and LaCe rare earth fluoride are mixed in a certain proportion and then water is added for slurrying, wherein the solid-liquid ratio (mass-volume ratio) of cerium oxide, LaCe rare earth fluoride and tap water is 1:1; the proportion of fluorine element in rare earth oxide is 1% to 8%; after fully stirring and waiting for the fluorination reaction to be completed, the material liquid is put into a QX-200 ball mill for ball milling to reduce the D50 of the rare earth oxide to 5 to 10 μm, and then the ball milled material liquid is put into an LPG series high-speed centrifugal granulation spray dryer for drying and dehydration, and the drying temperature is 150°C to 260°C; then the dried material from the spray dryer is put into a jet mill crusher for crushing and grading treatment, so that the dried material has a controllable particle size of 0.5 μm to 2.5 μm, and finally a Ce-based rare earth polishing powder with controllable particle size is obtained;

[0033] Step 2: Additive Compounding

[0034] High white aluminum silicate, ultrafine kaolin, precipitated silica, sodium hexametaphosphate and potassium chloride are selected as raw materials and compounded in a certain proportion to obtain a compound additive.

[0035] Specifically, high-white aluminum silicate with a porous fluffy structure, good absorbency, high brightness, low friction and wear, and excellent suspension performance is selected to prevent the self-aggregation of polishing powder particles and synergistically improve its suspension and dispersibility in the slurry state; ultrafine high-purity kaolin with flaky structure, particle size below 0.1μm and good water solubility is selected to increase the suspension of polishing powder particles; precipitated silica with a network structure is selected to improve the suspension of suspended particles in Ce-based polishing slurry and synergistically inhibit the agglomeration of deposited particles; sodium hexametaphosphate commonly used in commercial polishing powder is selected to improve the suspension performance of Ce-based polishing slurry; potassium chloride reagent is selected as the pH adjuster in Ce-based polishing slurry.

[0036] The amount of high white aluminum silicate added is 1‰ to 3‰ of the mass fraction of the Ce-based rare earth polishing powder prepared in step 1, the amount of ultrafine kaolin added is 1‰ to 3‰ of the mass fraction of the Ce-based rare earth polishing powder, the amount of precipitated silica added is 1‰ to 3‰ of the mass fraction of the Ce-based rare earth polishing powder, the amount of sodium hexametaphosphate added is 0.5‰ to 2.5‰ of the mass fraction of the Ce-based rare earth polishing powder, and the amount of potassium chloride added is 1‰ to 2.5‰ of the mass fraction of the Ce-based rare earth polishing powder.

[0037] Step 3: Add the compound additive prepared in step 2 to the Ce-based rare earth polishing powder prepared in step 1, and use a stirrer to fully stir and mix. The stirrer used is a plowshare stirrer, and the stirring time is not less than 30 minutes.

[0038] Step 4: Add tap water to the mixed product obtained in step 3 for beating to obtain a polishing slurry. During the beating process, a suspension densitometer is used to monitor the change in the instantaneous density value of the slurry, and observe whether the partially settled polishing particles become compacted after the slurry has been allowed to stand for a long time. In step 4, the solid-liquid ratio (solid-liquid mass volume ratio) of the Ce-based polishing slurry is 1:7 to 1:12, that is, the solid content of the polishing slurry is 8% to 15%.

[0039] Step 5: Take the polishing slurry obtained in step 4 and use an M200 flat surface precision grinding and polishing machine and an optical 3D surface profiler to evaluate the polishing performance.

[0040] Example 1

[0041] like Figure 1-3 The present embodiment provides a Ce-based polishing slurry compounding method capable of prolonging the settling time, comprising the following steps:

[0042] Step 1: First, cerium oxide and LaCe rare earth fluoride are mixed in a certain proportion so that the fluorine content accounts for 5% of the total rare earth oxide, and then 3 6m tap water is added to the steel-lined glass fiber reinforced plastic reaction tank in advance 3, and then add 6t of a mixture of cerium oxide and LaCe rare earth fluoride; the chemical composition of the added mixture of cerium oxide and LaCe rare earth fluoride is La: 34.84%, Ce: 65.03%, Pr: <0.001%, Nd: <0.01%, and the rare earth REO content is 90%; after slurrying, stir thoroughly to allow the mixture of cerium oxide and LaCe rare earth fluoride to undergo fluorination reaction.

[0043] In order to fully refine the particles of the rare earth oxide, the fluorinated slurry subjected to the fluorination reaction was ball-milled using a QX-200 ball mill to reduce the central particle size D50 of the rare earth oxide to 8 μm; then, the ball-milled small-particle rare earth slurry was dried and dehydrated using an LPG series high-speed centrifugal granulation spray dryer, and the drying temperature was 150° C. to 260° C. The spray-dried product was crushed and classified using an OLM-3.5 air flow crusher, and the central particle size D50 of the rare earth polishing powder after classification in this embodiment was 1.0 μm.

[0044] Step 2: Take 35g of the Ce-based rare earth polishing powder obtained in step 1, and take 0.070g of high white aluminum silicate according to 2‰ of the weight of the Ce-based polishing powder; take 0.070g of ultrafine kaolin according to 2‰ of the weight of the Ce-based polishing powder; take 0.070g of precipitated silica according to 2‰ of the weight of the Ce-based polishing powder; take 0.070g of sodium hexametaphosphate according to 2.0‰ of the weight of the Ce-based polishing powder; take 0.0525g of potassium chloride according to 1.5‰ of the weight of the Ce-based polishing powder;

[0045] Step 3: Add all the materials obtained in step 2 and mix them thoroughly. The solid content of the Ce-based polishing slurry is 12%, that is, 280 mL of tap water needs to be added, and then a glass rod is used to stir thoroughly to obtain the Ce-based rare earth polishing slurry.

[0046] Step 4: Place the Ce-based rare earth polishing slurry prepared in step 3 in a 350 mL measuring cylinder, use a densitometer to test its suspension density, and observe whether the partially settled polishing particles become agglomerated after the slurry is left standing for a long time. The results show that the initial suspension density of the Ce-based polishing slurry is 1.102 g / cm 3 After standing for 60 minutes, the suspension density value dropped to 1.090g / cm 3 After standing for 120 minutes, the suspension density value dropped to 1.083 g / cm 3 After standing for 180 minutes, the suspension density value dropped to 1.077 g / cm 3 After standing for 6 hours, the suspension density value dropped to 1.063g / cm 3 After standing for 8 hours, the suspension density value dropped to 1.049 g / cm 3It can be seen that the Ce-based polishing slurry still maintains good suspension after 8 hours, which can meet the concentration requirements in the actual polishing process. Take 50mL of Ce-based polishing slurry of the same concentration and place it in a colorimetric tube. After standing for 24 hours, shake the colorimetric tube thoroughly. It can be found that some of the sedimented particles at the bottom of the colorimetric tube are loose, and there is no agglomeration at the bottom. After it continues to stand for 48 hours, shake the colorimetric tube in the same way, and it can be observed that there is no agglomeration at the bottom of the colorimetric tube.

[0047] Step 5: Use an M200 flat precision grinding and polishing machine and an optical 3D surface profiler to evaluate the polishing performance of the prepared Ce-based rare earth polishing slurry. A polishing slurry with a solid-liquid mass volume ratio of 1:10 was configured for grinding test, and a polyurethane polishing pad was used to grind and polish B270 glass. The polishing head speed was 100r / min, the grinding pressure was 5Kg, the feeding frequency of the polishing slurry was 20Hz, and the polishing time was 30min. It was found that the polishing ability of the LaCe rare earth polishing slurry prepared in Example 1 of the invention was

[0048] 61 mg·30 min-1. The surface roughness Sa of the surface of the B270 glass polished by the Ce-based rare earth polishing slurry prepared by the method of Example 1 of the invention can be read from the 3D white light interference image and the profile curve of the optical surface profiler to be 0.978 nm.

[0049] Comparative Example 1

[0050] A commercially available lanthanum-cerium rare earth polishing powder with a center particle size of D50: 1.01 μm was selected for slurrying and then subjected to suspension density test and grinding performance test. The chemical composition of the powder is approximately La: 35%, Ce: 65%.

[0051] The lanthanum-cerium rare earth polishing powder in Comparative Example 1 was slurried (solid content was 12%) and then subjected to suspension density test. It can be found that the initial suspension density of the polishing slurry is 1.098 g / cm 3 After standing for 60 minutes, the suspension density value dropped to 1.067g / cm 3 After standing for 120 minutes, the suspension density value dropped to 1.060g / cm 3 After standing for 180 minutes, the suspension density value dropped to 1.055 g / cm 3 After standing for 6 hours, the suspension density value dropped to 1.046 g / cm 3 After standing for 8 hours, the suspension density value dropped to 1.023g / cm 3 , it can be seen that the polishing slurry is basically completely settled after 8 hours. Take 50mL of the polishing slurry in Comparative Example 1 with the same concentration and put it in a colorimetric tube. After standing for 12 hours, shake the colorimetric tube thoroughly. It can be found that some of the settled particles at the bottom of the colorimetric tube are agglomerated, and serious hardening occurs.

[0052] The lanthanum-cerium rare earth polishing powder in Comparative Example 1 was slurried to prepare a polishing slurry with a solid-liquid mass volume ratio of 1:10 for a grinding comparison test under the same conditions. The results showed that the polishing ability of the Ce-based rare earth polishing slurry prepared in Comparative Example 1 was 56 mg·30 min -1 From the 3D white light interference image and profile curve of the optical surface profiler, it can be seen that the surface roughness Sa of the B270 glass after polishing with the Ce-based rare earth polishing slurry of comparative example 1 of the invention is 1.246 nm.

[0053] Example 2

[0054] Step 1: The difference from Example 1 is that the central particle size D50 of the rare earth polishing powder after classification is 1.32 μm.

[0055] Step 2: Take 35g of the Ce-based rare earth polishing powder with a D50 of 1.32μm obtained in step 1; take 0.070g of high white aluminum silicate; take 0.070g of ultrafine kaolin; take 0.0525g of precipitated silica; take 0.070g of sodium hexametaphosphate; take 0.035g of potassium chloride; mix the above materials thoroughly and stir to obtain a mixed material;

[0056] Step 3: The solid content of the Ce-based polishing slurry with a D50 of 1.32 μm is 12%, that is, 280 mL of tap water is added to the mixed material obtained in step 2, and then the mixture is fully stirred with a glass rod to obtain the Ce-based polishing slurry.

[0057] Step 4: Place the polishing slurry prepared in step 3 in a 350 mL measuring cylinder and use a densitometer to test its suspension density. The results show that the initial suspension density of the Ce-based polishing slurry with a D50 of 1.32 μm is 1.099 g / cm 3 After standing for 60 minutes, the suspension density value dropped to 1.088g / cm 3 After standing for 120 minutes, the suspension density value dropped to 1.078g / cm 3 After standing for 180 minutes, the suspension density value dropped to 1.071 g / cm 3 After standing for 6 hours, the suspension density value dropped to 1.052g / cm 3 After standing for 8 hours, the suspension density value dropped to 1.036 g / cm 3 It can be seen that after 8 hours, the Ce-based polishing slurry with a D50 of 1.32μm still maintains good suspension and can meet the concentration requirements in the actual polishing process. Take 50mL of Ce-based polishing slurry with a D50 of 1.32μm of the same concentration and place it in a colorimetric tube. After standing for 24 hours, shake the colorimetric tube thoroughly. It can be found that some of the sedimented particles at the bottom of the colorimetric tube are loose, and there is no agglomeration at the bottom. After it continues to stand for 48 hours, shake the colorimetric tube in the same way, and it can be observed that there is no agglomeration at the bottom of the colorimetric tube.

[0058] Comparative Example 2

[0059] A commercially available lanthanum-cerium rare earth polishing powder with a center particle size of D50: 1.30 μm was selected for slurrying and then subjected to suspension density test and grinding performance test. The chemical composition of the powder is approximately La: 35%, Ce: 65%.

[0060] The lanthanum-cerium rare earth polishing powder in Comparative Example 2 was slurried (solid content was 12%) and then subjected to suspension density test. It can be found that the initial suspension density of the polishing slurry was 1.096 g / cm 3 After standing for 60 minutes, the suspension density value dropped to 1.063g / cm 3 After standing for 120 minutes, the suspension density value dropped to 1.052 g / cm 3 After standing for 180 minutes, the suspension density value dropped to 1.041 g / cm 3 After standing for 6 hours, the suspension density value dropped to 1.026g / cm 3 After standing for 8 hours, the suspension density value dropped to 1.010g / cm 3 , it can be seen that the polishing slurry is basically completely settled after 8 hours. Take 50mL of the polishing slurry in Comparative Example 2 with the same concentration and put it in a colorimetric tube. After standing for 12 hours, shake the colorimetric tube thoroughly. It can be found that some of the settled particles at the bottom of the colorimetric tube are agglomerated, and serious hardening occurs.

[0061] In summary, the present invention compounds the additives in the Ce-based polishing powder, thereby improving the added value of the Ce-based polishing powder product, which can prolong the sedimentation time of the Ce-based polishing slurry, ensure the effective concentration and polishing stability of the polishing slurry during use, and thus improve the polishing efficiency. The compounded additives of the present invention prolong the sedimentation time of the Ce-based polishing slurry, effectively avoid the phenomenon of the polishing slurry being blocked in the polishing equipment and the conveying pipeline, and alleviate the trouble of the operator repeatedly cleaning the blocked pipeline. The compounded additives of the present invention not only prolong the sedimentation time of the Ce-based polishing, but also the slurry does not harden after being left standing for a long time. During use, the user can turn on the agitator again to stir up all the materials for continued use, thereby also improving the utilization rate of the polishing powder particles.

Claims

1. A Ce-based polishing slurry compounding method capable of prolonging the settling time, characterized in that: The following steps are included: Step 1: Preparation of Ce-based rare earth polishing powder Cerium oxide and LaCe rare earth fluoride are mixed in a certain proportion, and then water is added to make a slurry, and the mixture is stirred sufficiently. After the fluorination reaction is completed, the mixture is put into a QX-200 ball mill for ball milling, and then the ball milled mixture is put into an LPG series high-speed centrifugal granulation spray dryer for drying and dehydration, and then the dried material from the spray dryer is put into an air flow mill crusher for crushing and grading, and finally a Ce-based rare earth polishing powder with controllable particle size is obtained; Step 2: Additive Compounding High white aluminum silicate, ultrafine kaolin, precipitated silica, sodium hexametaphosphate and potassium chloride are selected as raw materials and compounded in a certain proportion to obtain a compound additive; Step 3: adding the compound additive prepared in step 2 to the Ce-based rare earth polishing powder prepared in step 1, and using a stirrer to fully stir and mix; Step 4: Add tap water to the mixed product obtained in step 3 to prepare polishing slurry. During the beating process, a suspension densitometer is used to monitor the instantaneous density value change of the slurry, and observe whether the polishing particles that have settled partially after the slurry has been left to stand for a long time are agglomerated; Step 5: Take the polishing slurry obtained in step 4 and use an M200 flat surface precision grinding and polishing machine and an optical 3D surface profiler to evaluate the polishing performance.

2. The method for compounding a Ce-based polishing slurry capable of prolonging the settling time according to claim 1, characterized in that: In step 2, the selected high white aluminum silicate is a high white aluminum silicate with a porous fluffy structure, good absorbency, high brightness, low friction and wear, and excellent suspension performance; the selected ultrafine kaolin is an ultrafine high-purity kaolin with a flaky structure, a particle size of less than 0.1 μm and good water solubility; the selected precipitated silica is a precipitated silica with a network structure.

3. The method for compounding a Ce-based polishing slurry capable of prolonging the settling time according to claim 1, characterized in that: In step 1, the solid-liquid ratio of cerium oxide, LaCe rare earth fluoride and tap water is 1:1; the proportion of fluorine element in rare earth oxide is 1% to 8%; the liquid is put into a QX-200 ball mill for ball milling to reduce the D50 of the rare earth oxide to 5 to 10 μm; the temperature of the ball milled liquid in a spray dryer is 150°C to 260°C; the controllable particle size of the dried material in the air flow mill crusher is 0.5 μm to 2.5 μm.

4. The method for compounding a Ce-based polishing slurry capable of prolonging the settling time according to claim 1, characterized in that: In step 2, the amount of high white aluminum silicate added is 1‰ to 3‰ of the mass fraction of the Ce-based polishing powder, the amount of ultrafine kaolin added is 1‰ to 3‰ of the mass fraction of the Ce-based polishing powder, the amount of precipitated silica added is 1‰ to 3‰ of the mass fraction of the Ce-based polishing powder, the amount of sodium hexametaphosphate added is 0.5‰ to 2.5‰ of the mass fraction of the Ce-based polishing powder, and the amount of potassium chloride added is 1‰ to 2.5‰ of the mass fraction of the Ce-based polishing powder.

5. The method for compounding a Ce-based polishing slurry capable of prolonging the settling time according to claim 1, characterized in that: In step 3, the agitator used is a plowshare agitator, and the agitation time is not less than 30 minutes.

6. The method for compounding a Ce-based polishing slurry capable of prolonging the settling time according to claim 1, characterized in that: In step 4, the solid-liquid ratio of the Ce-based polishing slurry is 1:7 to 1:12, that is, the solid content of the polishing slurry is 8% to 15%.

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