Method for improving the concentration of the particle size distribution of rare earth oxide abrasives

Abstract

The present application relates to a kind of methods for improving the concentration of rare earth oxide abrasive particle size distribution, the method comprises: first, mixing water, rare earth oxide, dispersing agent and pH regulator, to obtain first slurry;Then, first slurry is carried out first sanding treatment, to obtain second slurry;Afterwards, second slurry and wetting agent are mixed, and heat cold alternation treatment is carried out, to obtain third slurry;Finally, the second sanding treatment of third slurry is carried out, the rotation speed of the second sanding treatment is less than the rotation speed of first sanding treatment, to obtain rare earth oxide abrasive.The method provided by the present application can effectively improve the concentration of abrasive particle size distribution, reduce the input of external energy, can save energy consumption, and be conducive to industrial application.

Description

Technical Field

[0001] This invention relates to the field of abrasive manufacturing technology, and specifically to a method for improving the particle size distribution concentration of rare earth oxide abrasives. Background Technology

[0002] Rare earth oxides, such as cerium oxide, are used as abrasive particles in chemical mechanical polishing (CMP) due to their oxygen vacancy structure and suitable isoelectric point. Cerium oxide abrasive particles, when applied to the TEOS polishing process, exhibit high polishing rates and selectivity, making them a preferred polishing material for TEOS. However, the polishing process places high demands on the particle size distribution of cerium oxide abrasive particles. If the abrasive particles contain a large number of small or large-diameter particles, resulting in a widened particle size distribution range, small-diameter particles tend to reduce the polishing rate, while large-diameter particles tend to cause more defects in the substrate, leading to a lower yield. Therefore, in the manufacturing process of abrasive particles, it is necessary to minimize the particle size distribution range and increase the particle size concentration.

[0003] Currently, the preparation process of existing calcined cerium oxide abrasives mainly includes calcination, dispersion, and crushing. Crushing involves breaking large cerium oxide particles into target particle sizes and stably suspending them in a dispersion medium. The crushing process typically employs ball milling or sand milling, using high rotational speeds to drive grinding beads to collide and compress the cerium oxide, breaking large particles into smaller ones. Due to the low hardness and large lattice defects of cerium oxide, it is easily over-crushed into small particles, resulting in a widened particle size distribution range. For example, CN1177012C discloses a cerium-based abrasive and its manufacturing method. This method involves crushing the abrasive raw material and then subjecting it to multiple classification processes to obtain the required abrasive. This method is not only complex but also has low utilization of the abrasive raw material, resulting in high production costs.

[0004] Therefore, it is of great significance to provide a method for preparing rare earth oxide abrasives and improving their particle size distribution concentration. Summary of the Invention

[0005] To address the above problems, the present invention aims to provide a method for improving the particle size distribution concentration of rare earth oxide abrasives. Compared with the prior art, the method provided by the present invention can effectively improve the particle size distribution concentration of abrasives, reduce the input of external energy, save energy consumption, and is beneficial to industrial applications.

[0006] To achieve this objective, the present invention adopts the following technical solution:

[0007] This invention provides a method for improving the particle size distribution concentration of rare earth oxide abrasives, the method comprising the following steps:

[0008] (1) Mix water, rare earth oxides, dispersant and pH adjuster to obtain the first slurry;

[0009] (2) The first slurry obtained in step (1) is subjected to a first sand milling process to obtain a second slurry;

[0010] (3) Mix the second slurry obtained in step (2) with the wetting agent, and then perform hot and cold alternating treatment to obtain the third slurry;

[0011] (4) The third slurry obtained in step (3) is subjected to a second sand milling process, wherein the rotation speed of the second sand milling process is less than the rotation speed of the first sand milling process, to obtain rare earth oxide abrasive.

[0012] In this invention, a first milling process is performed at a high rotational speed to break down large rare earth oxide particles or create crystal cracks. Then, a hot-cold alternating process is applied. First, at a higher temperature, the air in the cracks expands, allowing it to escape and the wetting agent to enter. Then, at a lower temperature, the cracks contract, and the wetting agent occupies the crack space. After several alternating cycles, the air in the crystal cracks is expelled, and the wetting agent occupies the crack space. Simultaneously, utilizing the principle of like dissolves like, the wetting agent dissolves the dispersant, causing the dispersant to accumulate at the crystal cracks. Next, a second milling process is performed at a lower rotational speed. The dispersant fully utilizes its charge repulsion effect, requiring only a lower rotational speed to break the abrasive particles into uniform particle sizes. The method provided by this invention reduces the input of external energy, saves energy consumption, avoids excessive particle breakage, and improves the particle size distribution concentration.

[0013] In this invention, water, rare earth oxides, dispersants, and pH adjusters can be mixed simultaneously, or any two of them can be mixed first, and then mixed with other components.

[0014] Preferably, the rare earth oxide in step (1) includes any one or a combination of at least two of cerium oxide, lanthanum oxide, or yttrium oxide, wherein typical but non-limiting combinations include a combination of cerium oxide and lanthanum oxide or a combination of cerium oxide and yttrium oxide, preferably cerium oxide.

[0015] Preferably, the dispersant in step (1) comprises any one or a combination of at least two of polyacrylic acid, polyacrylamide, sodium carboxymethyl cellulose, or polybenzenesulfonic acid, wherein typical but non-limiting combinations include a combination of polyacrylic acid and polyacrylamide or a combination of polyacrylamide and carboxymethyl cellulose.

[0016] Preferably, the weight-average molecular weight of the dispersant is 1,000-10,000, for example, it can be 1,000, 2,000, 3,000, 4,000, 5,000, 6,000, 7,000, 8,000, 9,000 or 10,000, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0017] Preferably, the amount of dispersant added to the first slurry is 500-5000 ppm, for example, it can be 500 ppm, 1000 ppm, 1500 ppm, 2000 ppm, 2500 ppm, 3000 ppm, 3500 ppm, 4000 ppm, 4500 ppm or 5000 ppm, but is not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0018] Preferably, the mass percentage of rare earth oxides in the first slurry in step (1) is 1-50%, for example, it can be 1%, 2%, 4%, 6%, 8%, 10%, 12%, 14%, 16%, 18%, 20%, 22%, 24%, 26%, 28%, 30%, 32%, 34%, 36%, 38%, 40%, 42%, 44%, 46%, 48% or 50%, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0019] Preferably, the average particle size of the rare earth oxides in the first slurry is 10-60 μm, for example, it can be 10 μm, 15 μm, 20 μm, 25 μm, 30 μm, 35 μm, 40 μm, 45 μm, 50 μm, 55 μm or 60 μm, but is not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0020] Preferably, the pH adjuster in step (1) comprises any one or a combination of at least two of potassium hydroxide, imidazole, triethylamine, phosphoric acid, hydrochloric acid, acetic acid or oxalic acid, wherein typical but non-limiting combinations include a combination of potassium hydroxide and imidazole or a combination of phosphoric acid and hydrochloric acid.

[0021] Preferably, the pH value of the first slurry is 5-10, for example, it can be 5, 6, 7, 8, 9 or 10, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0022] Preferably, the rotation speed of the first sand milling process in step (2) is 1000-3000 rpm, for example, it can be 1000 rpm, 1100 rpm, 1200 rpm, 1400 rpm, 1500 rpm, 1600 rpm, 1800 rpm, 1900 rpm, 2000 rpm, 2100 rpm, 2200 rpm, 2400 rpm, 2500 rpm, 2700 rpm, 2800 rpm or 3000 rpm, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0023] In this invention, it is preferable to control the rotation speed of the first grinding process within a specific range. This avoids the rare earth oxide abrasive being too difficult to break due to excessively slow rotation speed, resulting in excessively large particle size. It also avoids the crystals having fewer and shallower cracks due to excessively slow rotation speed, making it difficult to fully utilize the charge repulsion effect of the dispersant to break the crystals. At the same time, it avoids the rare earth oxide being excessively broken into smaller crystals in a short time due to excessively high rotation speed, making it difficult to control the particle size.

[0024] Preferably, the particle size of the grinding beads used in the first sanding process is 0.1-0.5 mm, for example, it can be 0.1 mm, 0.15 mm, 0.2 mm, 0.25 mm, 0.3 mm, 0.35 mm, 0.4 mm, 0.45 mm or 0.5 mm, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0025] Preferably, the time for the first sanding process is 1-4 hours, for example, it can be 1 hour, 1.5 hours, 2 hours, 2.5 hours, 3 hours, 3.5 hours or 4 hours, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0026] Preferably, the hot-cold alternation process in step (3) includes: alternating between heat treatment and cold treatment in sequence as one alternation process, and performing the alternation process 1 to 3 times, for example, 1 time, 2 times or 3 times.

[0027] Preferably, the hot-cold alternation process is performed under ultrasonic conditions.

[0028] In this invention, ultrasonic treatment can further promote the expulsion of gas from crystal cracks and promote the entry of wetting agent into the cracks.

[0029] Preferably, the power of the ultrasound is 700-1400W, for example, it can be 700W, 800W, 900W, 1000W, 1100W, 1200W, 1300W or 1400W, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0030] Preferably, the heat treatment temperature is 50-70℃, for example, it can be 50℃, 52℃, 54℃, 56℃, 58℃, 60℃, 62℃, 64℃, 66℃, 68℃ or 70℃, but is not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0031] In this invention, it is preferable to control the heat treatment temperature within a specific range. This avoids the gas in the cracks from not being able to fully expand and escape due to excessively low heat treatment temperature, while also avoiding the loss of the added wetting agent due to excessively high temperature. Furthermore, excessively high temperature will also increase the requirements for equipment, which is not conducive to industrial production.

[0032] Preferably, the heat treatment time is 5-10 minutes, for example, 5 minutes, 6 minutes, 7 minutes, 8 minutes, 9 minutes or 10 minutes, but not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0033] Preferably, the temperature of the cold treatment is 5-10℃, for example, it can be 5℃, 6℃, 7℃, 8℃, 9℃ or 10℃, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0034] In this invention, it is preferable to control the temperature of the cold treatment within a specific range to avoid the slurry freezing and losing fluidity due to excessively low temperature, making it difficult for the wetting agent to flow into and wet the crystal cracks; at the same time, it is also to avoid the cold treatment temperature being too high, which would make it difficult to cool and contract the gas in the crystal cracks, thus making it difficult for the wetting agent to occupy the space of the contraction to wet the particles.

[0035] Preferably, the temperature difference between the heat treatment and the cold treatment is 40-65℃, for example, it can be 40℃, 42℃, 45℃, 48℃, 50℃, 52℃, 55℃, 58℃, 60℃, 62℃ or 65℃, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0036] Preferably, the cooling time is 5-10 minutes, for example, 5 minutes, 6 minutes, 7 minutes, 8 minutes, 9 minutes or 10 minutes, but not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0037] Preferably, the wetting agent in step (3) includes any one or a combination of at least two of isopropanol, ethanol, ethylene glycol or butanol, wherein typical but non-limiting combinations include a combination of isopropanol and ethanol or a combination of ethanol and ethylene glycol.

[0038] Preferably, the amount of wetting agent added to the third slurry is 1000-2000 ppm, for example, it can be 1000 ppm, 1100 ppm, 1200 ppm, 1300 ppm, 1400 ppm, 1500 ppm, 1600 ppm, 1700 ppm, 1800 ppm, 1900 ppm or 2000 ppm, but is not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0039] Preferably, the rotation speed of the second sand milling process in step (4) is 100-500 rpm, for example, it can be 100 rpm, 120 rpm, 140 rpm, 160 rpm, 180 rpm, 200 rpm, 220 rpm, 240 rpm, 260 rpm, 280 rpm, 300 rpm, 320 rpm, 340 rpm, 360 rpm, 380 rpm, 400 rpm, 420 rpm, 440 rpm, 460 rpm, 480 rpm or 500 rpm, but is not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0040] In this invention, it is preferable to control the rotation speed of the second sand milling process within a specific range. This avoids the situation where the rotation speed of the second sand milling process is too high, which would cause the grains to be severely broken and make it difficult to control the size of the particles. At the same time, it avoids the situation where the rotation speed is too low, which would make it difficult to break up the cracks in the grains coated by the dispersant, resulting in excessively large particle sizes and low particle size distribution.

[0041] Preferably, the particle size of the grinding beads used in the second sanding process is 0.1-0.5 mm, for example, it can be 0.1 mm, 0.15 mm, 0.2 mm, 0.25 mm, 0.3 mm, 0.35 mm, 0.4 mm, 0.45 mm or 0.5 mm, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0042] Preferably, the second sanding process takes 2-4 hours, for example, 2 hours, 2.2 hours, 2.4 hours, 2.6 hours, 2.8 hours, 3 hours, 3.2 hours, 3.4 hours, 3.6 hours, 3.8 hours or 4 hours, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0043] Preferably, the D50 particle size of the rare earth oxide abrasive is 100-200nm, for example, it can be 100nm, 110nm, 120nm, 130nm, 140nm, 150nm, 160nm, 170nm, 180nm, 190nm or 200nm, but is not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0044] Preferably, the particle size distribution width (D90-D10) / D50 of the rare earth oxide abrasive is in the range of 0.45-0.8, for example, it can be 0.45, 0.5, 0.55, 0.6, 0.65, 0.7, 0.75 or 0.8, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable, preferably 0.45-0.65.

[0045] As a preferred embodiment of the present invention, the method includes the following steps:

[0046] (1) Mix water, rare earth oxides, dispersant and pH adjuster to obtain the first slurry;

[0047] The rare earth oxides include any one or a combination of at least two of cerium oxide, lanthanum oxide, or yttrium oxide; the dispersant includes any one or a combination of at least two of polyacrylic acid, polyacrylamide, sodium carboxymethyl cellulose, or polybenzene sulfonic acid; the weight-average molecular weight of the dispersant is 1000-10000; the amount of dispersant added to the first slurry is 500-5000 ppm; the mass percentage of rare earth oxides in the first slurry is 1-50%; the average particle size of rare earth oxides in the first slurry is 10-60 μm; the pH adjuster includes any one or a combination of at least two of potassium hydroxide, imidazole, triethylamine, phosphoric acid, hydrochloric acid, acetic acid, or oxalic acid; and the pH value of the first slurry is 5-10.

[0048] (2) The first slurry obtained in step (1) is subjected to a first sand milling process for 1-4 hours with grinding beads with a particle size of 0.1-0.5 mm at a speed of 1000-3000 rpm to obtain a second slurry;

[0049] (3) Mix the second slurry obtained in step (2) with a wetting agent, wherein the wetting agent includes any one or a combination of at least two of isopropanol, ethanol, ethylene glycol or butanol, and the amount of the wetting agent added is 1000-2000 ppm. Then, perform heat and cold alternating treatment under ultrasonic conditions with a power of 700-1400W. The heat and cold alternating treatment process includes: performing heat treatment and cold treatment sequentially as one alternating process, and performing the alternating process 1-3 times. The temperature of the heat treatment is 50-70℃ and the time is 5-10 min. The temperature of the cold treatment is 5-10℃ and the time is 5-10 min. The temperature difference between the heat treatment and the cold treatment is 40-65℃ to obtain a third slurry.

[0050] (4) The third slurry obtained in step (3) is subjected to a second sand milling treatment at a speed of 100-500 rpm for 2-4 hours with grinding beads with a particle size of 0.1-0.5 mm to obtain rare earth oxide abrasive. The D50 particle size of the rare earth oxide abrasive is 100-200 nm, and the particle size distribution width (D90-D10) / D50 ranges from 0.45 to 0.8.

[0051] Compared with the prior art, the present invention has the following beneficial effects:

[0052] (1) The method provided by the present invention first performs a first grinding process at a high speed to generate crystal cracks in rare earth oxides. Then, through alternating hot and cold treatment, the wetting agent carries the dispersant to fully penetrate into the crack space. Finally, by utilizing the charge repulsion effect of the dispersant, a second grinding process at a low speed is required to obtain rare earth oxide abrasive with high particle size distribution concentration. This effectively prevents excessive particle breakage, avoids the input of external energy, shortens the process flow, and saves production energy consumption.

[0053] (2) The method provided by the present invention can effectively improve the particle size distribution concentration of rare earth oxide abrasives, which is expressed as particle size distribution width (D90-D10) / D50. The smaller the value, the narrower the distribution range. The present invention can keep the particle size distribution width of rare earth oxide abrasives in the range of 0.45-0.90, and under better conditions, it can keep it in the range of 0.45-0.65. Attached Figure Description

[0054] Figure 1 This is a TEM image of the rare earth oxide abrasive obtained in Example 1 of the present invention;

[0055] Figure 2 This is a TEM image of the rare earth oxide abrasive obtained in Example 3 of the present invention. Detailed Implementation

[0056] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention.

[0057] Example 1

[0058] This embodiment provides a method for improving the particle size distribution concentration of rare earth oxide abrasives, the method comprising the following steps:

[0059] (1) Mix water and polyacrylic acid (weight average molecular weight of 5000), stir until completely dissolved, then add pH adjuster potassium hydroxide and cerium oxide (average particle size of 20μm), stir to obtain the first slurry; the amount of polyacrylic acid added in the first slurry is 500ppm, the mass percentage of cerium oxide is 1%, and the pH value of the first slurry is 8.

[0060] (2) The first slurry obtained in step (1) is subjected to a first sand milling treatment for 1 hour at a speed of 2000 rpm using zirconia grinding beads with a diameter of 0.3 mm to obtain a second slurry.

[0061] (3) Mix the second slurry obtained in step (2) with isopropanol, wherein the amount of isopropanol added is 1000 ppm, and then perform ultrasonic treatment with alternating hot and cold treatment under the condition of 1000 W power. The alternating hot and cold treatment process includes: first ultrasonic treatment at 50°C for 5 min, and then ultrasonic treatment at 5°C for 5 min to obtain the third slurry.

[0062] (4) The third slurry obtained in step (3) is subjected to a second sand milling treatment at a speed of 500 rpm for 2 hours using zirconia grinding beads with a diameter of 0.3 mm to obtain rare earth oxide abrasive, namely cerium oxide abrasive.

[0063] The TEM image of the rare earth oxide abrasive obtained in this embodiment is as follows: Figure 1 As shown, from Figure 1 It can be seen that the particle size of rare earth oxide abrasives is relatively uniform.

[0064] Example 2

[0065] This embodiment provides a method for improving the particle size distribution concentration of rare earth oxide abrasives, the method comprising the following steps:

[0066] (1) Mix water and polyacrylamide (weight average molecular weight of 2000), stir until completely dissolved, then add pH adjuster imidazole and cerium oxide (average particle size of 10μm), stir to obtain the first slurry; the amount of polyacrylamide added in the first slurry is 2000ppm, the mass percentage of cerium oxide is 35%, and the pH value of the first slurry is 10.

[0067] (2) The first slurry obtained in step (1) is subjected to a first sand milling treatment for 2 hours at a speed of 3000 rpm using zirconia grinding beads with a diameter of 0.5 mm to obtain a second slurry.

[0068] (3) Mix the second slurry obtained in step (2) with ethanol, wherein the amount of ethanol added is 1500 ppm, and then perform ultrasonic treatment with alternating hot and cold treatment at a power of 700 W. The alternating hot and cold treatment process includes: first ultrasonic treatment at 60°C for 10 min, and then ultrasonic treatment at 10°C for 10 min to obtain the third slurry.

[0069] (4) The third slurry obtained in step (3) is subjected to a second sand milling treatment at a speed of 300 rpm for 2 hours using zirconia grinding beads with a diameter of 0.5 mm to obtain rare earth oxide abrasive, namely cerium oxide abrasive.

[0070] Example 3

[0071] This embodiment provides a method for improving the particle size distribution concentration of rare earth oxide abrasives, the method comprising the following steps:

[0072] (1) Mix water and sodium carboxymethyl cellulose (weight average molecular weight of 1000), stir until completely dissolved, then add pH adjuster triethylamine and cerium oxide (average particle size of 40 μm), stir to obtain the first slurry; the amount of sodium carboxymethyl cellulose added in the first slurry is 1000 ppm, the mass percentage of cerium oxide is 10%, and the pH value of the first slurry is 9.

[0073] (2) The first slurry obtained in step (1) is subjected to a first sand milling treatment for 2 hours at a speed of 1000 rpm using zirconia grinding beads with a diameter of 0.1 mm to obtain a second slurry;

[0074] (3) Mix the second slurry obtained in step (2) with ethylene glycol, wherein the amount of ethylene glycol added is 2000 ppm, and then perform ultrasonic treatment with alternating hot and cold treatment at a power of 1400 W. The alternating hot and cold treatment process includes: first ultrasonic treatment at 55°C for 6 min, and then ultrasonic treatment at 6°C for 6 min to obtain the third slurry.

[0075] (4) The third slurry obtained in step (3) is subjected to a second sand milling treatment at a speed of 100 rpm for 3 hours using zirconia grinding beads with a diameter of 0.1 mm to obtain rare earth oxide abrasive, namely cerium oxide abrasive.

[0076] The TEM image of the rare earth oxide abrasive obtained in this embodiment is as follows: Figure 2 As shown, from Figure 2 It can be seen that the particle size of rare earth oxide abrasives is relatively uniform.

[0077] Example 4

[0078] This embodiment provides a method for improving the particle size distribution concentration of rare earth oxide abrasives, the method comprising the following steps:

[0079] (1) Mix water and polybenzenesulfonic acid (weight average molecular weight of 10,000), stir until completely dissolved, then add pH adjuster phosphoric acid and cerium oxide (average particle size of 60 μm), stir to obtain the first slurry; the amount of polybenzenesulfonic acid added in the first slurry is 5,000 ppm, the mass percentage of cerium oxide is 50%, and the pH value of the first slurry is 5.

[0080] (2) The first slurry obtained in step (1) is subjected to a first sand milling treatment for 1 hour at a rotation speed of 2500 rpm using zirconia grinding beads with a diameter of 0.2 mm to obtain a second slurry;

[0081] (3) Mix the second slurry obtained in step (2) with butanol, wherein the amount of butanol added is 1600 ppm, and then perform ultrasonic treatment with alternating hot and cold treatment at a power of 800 W. The alternating hot and cold treatment process includes: first ultrasonic treatment at 70°C for 5 min, and then ultrasonic treatment at 10°C for 6 min to obtain the third slurry.

[0082] (4) The third slurry obtained in step (3) is subjected to a second sand milling treatment at a speed of 200 rpm for 3 hours using zirconia grinding beads with a diameter of 0.2 mm to obtain rare earth oxide abrasive, namely cerium oxide abrasive.

[0083] Example 5

[0084] This embodiment provides a method for improving the particle size distribution concentration of rare earth oxide abrasives, the method comprising the following steps:

[0085] (1) Mix water and polyacrylic acid (weight average molecular weight of 6000), stir until completely dissolved, then add pH adjuster hydrochloric acid and cerium oxide (average particle size of 50μm), stir to obtain the first slurry; the amount of polyacrylic acid added in the first slurry is 3500ppm, the mass percentage of cerium oxide is 50%, and the pH value of the first slurry is 6.

[0086] (2) The first slurry obtained in step (1) is subjected to a first sand milling treatment for 2 hours at a speed of 2000 rpm using zirconia grinding beads with a diameter of 0.4 mm to obtain a second slurry.

[0087] (3) Mix the second slurry obtained in step (2) with isopropanol, wherein the amount of isopropanol added is 1600 ppm, and then perform ultrasonic treatment with alternating hot and cold treatment at a power of 900 W. The alternating hot and cold treatment process includes: first ultrasonic treatment at 65°C for 5 min, and then ultrasonic treatment at 7°C for 10 min to obtain the third slurry.

[0088] (4) The third slurry obtained in step (3) is subjected to a second sand milling treatment at a speed of 300 rpm for 3 hours using zirconia grinding beads with a diameter of 0.4 mm to obtain rare earth oxide abrasive, namely cerium oxide abrasive.

[0089] Example 6

[0090] This embodiment provides a method for improving the particle size distribution concentration of rare earth oxide abrasives, the method comprising the following steps:

[0091] (1) Mix water and polyacrylamide (weight average molecular weight of 8000), stir until completely dissolved, then add pH adjuster acetic acid and cerium oxide (average particle size of 60μm), stir to obtain the first slurry; the amount of polyacrylamide added in the first slurry is 4000ppm, the mass percentage of cerium oxide is 30%, and the pH value of the first slurry is 7.

[0092] (2) The first slurry obtained in step (1) is subjected to a first sand milling treatment for 4 hours at a speed of 1800 rpm using zirconia grinding beads with a diameter of 0.4 mm to obtain a second slurry.

[0093] (3) Mix the second slurry obtained in step (2) with ethylene glycol, wherein the amount of ethylene glycol added is 1900 ppm, and then perform ultrasonic treatment with alternating hot and cold treatment under the condition of 1300W power. The alternating hot and cold treatment process includes: first ultrasonic treatment at 50°C for 5 min, then ultrasonic treatment at 5°C for 5 min, then ultrasonic treatment at 50°C for 5 min, and then ultrasonic treatment at 5°C for 5 min to obtain the third slurry;

[0094] (4) The third slurry obtained in step (3) is subjected to a second sand milling treatment at a speed of 250 rpm for 4 hours using zirconia grinding beads with a diameter of 0.4 mm to obtain rare earth oxide abrasive, namely cerium oxide abrasive.

[0095] Example 7

[0096] This embodiment provides a method for improving the particle size distribution concentration of rare earth oxide abrasives, the method comprising the following steps:

[0097] (1) Mix water and polybenzenesulfonic acid (weight average molecular weight of 6000), stir until completely dissolved, then add pH adjuster oxalic acid and cerium oxide (average particle size of 30μm), stir to obtain the first slurry; the amount of polybenzenesulfonic acid added in the first slurry is 1500ppm, the mass percentage of cerium oxide is 25%, and the pH value of the first slurry is 6.

[0098] (2) The first slurry obtained in step (1) is subjected to a first sand milling treatment for 3 hours at a speed of 1000 rpm using zirconia grinding beads with a diameter of 0.5 mm to obtain a second slurry.

[0099] (3) Mix the second slurry obtained in step (2) with butanol, wherein the amount of butanol added is 2000 ppm, and then perform ultrasonic treatment with alternating hot and cold treatment under the power of 1200W. The alternating hot and cold treatment process includes: first ultrasonic treatment at 50°C for 5 min, then ultrasonic treatment at 5°C for 5 min, then ultrasonic treatment at 50°C for 5 min, then ultrasonic treatment at 5°C for 5 min, then ultrasonic treatment at 50°C for 5 min, and then ultrasonic treatment at 5°C for 5 min to obtain the third slurry;

[0100] (4) The third slurry obtained in step (3) is subjected to a second sand milling treatment at a speed of 500 rpm for 4 hours using zirconia grinding beads with a diameter of 0.5 mm to obtain rare earth oxide abrasive, namely cerium oxide abrasive.

[0101] Example 8

[0102] This embodiment provides a method for improving the particle size distribution concentration of rare earth oxide abrasives. The only difference between this method and Example 1 is that the amount of isopropanol added is 500 ppm.

[0103] Example 9

[0104] This embodiment provides a method for improving the particle size distribution concentration of rare earth oxide abrasives. The only difference between this method and Embodiment 1 is that the heat treatment temperature is adjusted to 40°C, so that the temperature difference between the heat treatment and the cold treatment is 35°C.

[0105] Example 10

[0106] This embodiment provides a method for improving the particle size distribution concentration of rare earth oxide abrasives. The only difference between this method and Embodiment 1 is that the heat treatment temperature is adjusted to 80°C, so that the temperature difference between the heat treatment and the cold treatment is 75°C.

[0107] Example 11

[0108] This embodiment provides a method for improving the particle size distribution concentration of rare earth oxide abrasives. The only difference between this method and Embodiment 1 is that the rotation speed of the first sand milling process is 800 rpm.

[0109] Example 12

[0110] This embodiment provides a method for improving the particle size distribution concentration of rare earth oxide abrasives. The only difference between this method and Embodiment 1 is that the rotation speed of the first sand milling process is 3500 rpm.

[0111] Example 13

[0112] This embodiment provides a method for improving the particle size distribution concentration of rare earth oxide abrasives. The only difference between this method and Embodiment 1 is that the rotation speed of the second sand milling process is 50 rpm.

[0113] Example 14

[0114] This embodiment provides a method for improving the particle size distribution concentration of rare earth oxide abrasives. The only difference between this method and Embodiment 1 is that the rotation speed of the second sand milling process is 550 rpm.

[0115] Comparative Example 1

[0116] This comparative example provides a method for preparing rare earth oxide abrasives. The only difference from Example 1 is that the rotation speed of the first sand milling process is adjusted to 500 rpm and the rotation speed of the second sand milling process is adjusted to 2000 rpm, that is, the rotation speed of the first sand milling process is < the rotation speed of the second sand milling process.

[0117] Comparative Example 2

[0118] This comparative example provides a method for preparing rare earth oxide abrasives. The only difference from Example 1 is that steps (3) and (4) are omitted, and the first slurry in step (2) is milled at a speed of 2000 rpm for 3 hours.

[0119] Comparative Example 3

[0120] This comparative example provides a method for preparing rare earth oxide abrasives. The only difference from Example 1 is that steps (3) and (4) are omitted, and the first slurry in step (2) is milled at 500 rpm for 3 hours.

[0121] Comparative Example 4

[0122] This comparative example provides a method for preparing rare earth oxide abrasives. The only difference from Example 1 is that step (3) is omitted, and the second slurry obtained in step (2) is directly subjected to the second sand milling process.

[0123] The D50, D90, and D10 particle sizes of the cerium oxide abrasives prepared in Examples 1-14 and Comparative Examples 1-4 were measured using a laser particle size analyzer. The particle size distribution width (D90-D10) / D50 was calculated. The results of the D50 particle size and (D90-D10) / D50 are shown in Table 1.

[0124] Table 1

[0125]

[0126]

[0127] The following points can be observed from the data in Table 1:

[0128] (1) As can be seen from the data of Examples 1-14, the method provided by the present invention can effectively improve the particle size distribution concentration of rare earth oxide abrasives. The smaller the particle size distribution width (D90-D10) / D50, the narrower the distribution range. The present invention can keep the particle size distribution width of rare earth oxide abrasives in the range of 0.45-0.90, and under better conditions, it can keep it in the range of 0.45-0.65.

[0129] (2) Comparing the data of Example 1 and Example 8, it can be seen that the only difference between Example 8 and Example 1 is that the amount of wetting agent added is not within the preferred range of the present invention. The particle size distribution width in Example 8 is significantly higher than that in Example 1. It can be seen that by controlling the amount of wetting agent added in the present invention, the wetting effect on crystal cracks can be further promoted, thereby giving full play to the charge repulsion effect of the dispersant and thus improving the particle size distribution concentration of rare earth oxide abrasive.

[0130] (3) A comprehensive comparison of the data from Examples 1 and 9-10 shows that the only difference between Examples 9-10 and Example 1 is that the temperature difference between heat treatment and cold treatment is not within the preferred range of the present invention. The particle size distribution width in Example 1 is significantly smaller than that in Examples 9-10. Therefore, the present invention preferably controls the temperature difference between heat treatment and cold treatment, which can further promote the wetting agent to enter the crystal crack, thereby giving full play to the charge repulsion effect of the dispersant, and thus improving the particle size distribution concentration of rare earth oxide abrasive.

[0131] (4) A comprehensive comparison of the data from Examples 1 and 11-14 shows that the only difference between Examples 11-12 and Example 1 is that the rotation speed of the first sand milling process is not within the preferred range of the present invention. The only difference between Examples 13-14 and Example 1 is that the rotation speed of the second sand milling process is not within the preferred range of the present invention. The particle size distribution width in Example 1 is significantly smaller than that in Examples 11-14. Therefore, it can be seen that the present invention preferably controls the rotation speed of the first sand milling process and the second sand milling process within a specific range, which can further improve the particle size distribution concentration of rare earth oxide abrasive.

[0132] (5) A comprehensive comparison of the data from Example 1 and Comparative Examples 1-4 shows that the only difference between Comparative Example 1 and Example 1 is that the rotation speed of the first sand milling treatment is lower than that of the second sand milling treatment. The only difference between Comparative Examples 2-3 and Example 1 is that only one rotation speed is used for sand milling. The only difference between Comparative Example 4 and Example 1 is that no wetting agent hot-cold alternation treatment is performed in Comparative Example 4. The particle size distribution width in Example 1 is significantly smaller than that in Comparative Examples 1-4. It can be seen that this application can improve the particle size distribution concentration of rare earth oxide abrasives by combining the first sand milling treatment, the wetting agent hot-cold alternation treatment and the second sand milling treatment, and controlling the first sand milling treatment to be performed at a higher rotation speed and then the second sand milling treatment to be performed at a lower rotation speed.

[0133] In summary, the method provided by this invention can effectively improve the particle size distribution concentration of abrasives, reduce the input of external energy, save energy consumption, and is beneficial for industrial applications.

[0134] The applicant declares that the above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.

Claims

1. A method for improving the particle size distribution concentration of rare earth oxide abrasives, characterized in that, The method includes the following steps: (1) Mix water, rare earth oxides, dispersant and pH adjuster to obtain the first slurry; (2) The first slurry obtained in step (1) is subjected to a first sand milling process to obtain a second slurry; (3) Mix the second slurry obtained in step (2) with the wetting agent, and then perform hot and cold alternating treatment to obtain the third slurry; (4) The third slurry obtained in step (3) is subjected to a second sand milling process, wherein the rotation speed of the second sand milling process is less than that of the first sand milling process, to obtain rare earth oxide abrasive. The rotational speed of the first sand milling process is 1000-3000 rpm; The second grinding process is performed at a speed of 100-500 rpm; First, a first sand milling process is performed at a relatively high speed to induce crystal cracks in the rare earth oxides. Then, through alternating hot and cold treatment, the wetting agent carries the dispersant into the crack space. Finally, the second sand milling process is performed at a relatively low speed by utilizing the charge repulsion effect of the dispersant.

2. The method according to claim 1, characterized in that, The rare earth oxide in step (1) includes any one or a combination of at least two of cerium oxide, lanthanum oxide, or yttrium oxide.

3. The method according to claim 2, characterized in that, The rare earth oxide mentioned in step (1) is cerium oxide.

4. The method according to claim 1, characterized in that, The dispersant in step (1) includes any one or a combination of at least two of polyacrylic acid, polyacrylamide, sodium carboxymethyl cellulose, or polybenzenesulfonic acid.

5. The method according to claim 1, characterized in that, The weight-average molecular weight of the dispersant is 1000-10000.

6. The method according to claim 1, characterized in that, The amount of dispersant added in the first slurry is 500-5000 ppm.

7. The method according to claim 1, characterized in that, Step (1) The mass percentage of rare earth oxides in the first slurry is 1-50%.

8. The method according to claim 1, characterized in that, The average particle size of rare earth oxides in the first slurry is 10-60 μm.

9. The method according to claim 1, characterized in that, The pH adjuster in step (1) includes any one or a combination of at least two of potassium hydroxide, imidazole, triethylamine, phosphoric acid, hydrochloric acid, acetic acid or oxalic acid.

10. The method according to claim 1, characterized in that, The pH value of the first slurry is 5-10.

11. The method according to claim 1, characterized in that, In step (2), the particle size of the grinding beads used in the first sand grinding process is 0.1-0.5 mm.

12. The method according to claim 1, characterized in that, The first sand milling process takes 1-4 hours.

13. The method according to claim 1, characterized in that, The hot-cold alternation process in step (3) includes: alternating heat treatment and cold treatment in sequence as one alternation process, and performing the alternation process 1-3 times.

14. The method according to claim 1, characterized in that, The hot-cold alternation process is carried out under ultrasonic conditions.

15. The method according to claim 14, characterized in that, The power of the ultrasound is 700-1400W.

16. The method according to claim 13, characterized in that, The heat treatment temperature is 50-70℃.

17. The method according to claim 13, characterized in that, The heat treatment time is 5-10 minutes.

18. The method according to claim 13, characterized in that, The temperature for the cold treatment is 5-10℃.

19. The method according to claim 13, characterized in that, The cooling process takes 5-10 minutes.

20. The method according to claim 13, characterized in that, The temperature difference between the heat treatment and the cold treatment is 40-65℃.

21. The method according to claim 1, characterized in that, The wetting agent in step (3) includes any one or a combination of at least two of isopropanol, ethanol, ethylene glycol or butanol.

22. The method according to claim 1, characterized in that, The amount of wetting agent added to the third slurry is 1000-2000 ppm.

23. The method according to claim 1, characterized in that, In step (4), the particle size of the grinding beads used in the second sand grinding process is 0.1-0.5 mm.

24. The method according to claim 1, characterized in that, The second sand milling process takes 2-4 hours.

25. The method according to claim 1, characterized in that, The rare earth oxide abrasive has a D50 particle size of 100-200 nm.

26. The method according to claim 1, characterized in that, The particle size distribution width (D90-D10) / D50 of the rare earth oxide abrasive ranges from 0.45 to 0.

8.

27. The method according to claim 26, characterized in that, The particle size distribution width (D90-D10) / D50 of the rare earth oxide abrasive ranges from 0.45 to 0.65.

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