Method for preparing high-grade low-chloride large-particle crystal form cerous carbonate normal salt

Abstract

The invention discloses a method for preparing high-grade low-chloride large-particle crystal form cerous carbonate normal salt, which comprises the following steps: diluting rare earth in a cerium chloride solution with pure water until the rare earth concentration is 0.23-0.35 mol / L and the pH value is 2-5; preparing an ammonium bicarbonate solution by using pure water, and controlling the concentration of the ammonium bicarbonate solution to be 2.2-2.6 mol / L; adding seed crystal cerium carbonate and an ammonium bicarbonate solution into the cerium chloride solution, stirring, and carrying out carbon precipitation reaction at the reaction temperature of 50 + / -2 DEG C; and leaching the cerium carbonate slurry by using leaching water, and carrying out suction filtration to obtain the large-particle crystal form cerium carbonate. An ammonium bicarbonate precipitation method is used, additives are not needed, the large-particle-size cerium carbonate product is prepared by controlling main factors influencing precipitation, and the purpose that the particle size of the carbonate product is controllable is achieved.

Description

Technical Field

[0001] The invention belongs to the technical field of hydrometallurgy, and in particular relates to a method for preparing high-grade, low-chloride, large-particle crystalline cerium carbonate. Background Art

[0002] Controlling the physical properties of rare earth products has become a key technology in the development of the rare earth industry. The particle size of rare earth powders directly determines their application effectiveness. Powders of varying particle sizes can be used to produce ceramics, fluorescent materials, electronic materials, and other materials with varying requirements. The particle size of polishing powders directly determines polishing efficiency and the achievable finish. Therefore, particle size distribution is a crucial performance indicator for rare earth powders.

[0003] Currently, with the development of new materials technology, rare earth compounds with controllable particle size have shown good market prospects. In addition to the specific application fields of small-particle rare earth compounds, large-particle rare earth compounds also have a broad application market, so the research on the preparation of large-particle cerium carbonate is of great significance.

[0004] China Publication No. CN115672238B discloses a method for preparing a large-particle size and high-density polishing powder precursor without ammonia nitrogen. S1, first add one cubic meter of extracted cerium liquid into the interior of the reaction chamber through the extracted cerium liquid inlet pipe, then add 9.5 cubic meters of pure water to the reaction chamber at one time through the pure water inlet pipe to dilute the extracted cerium liquid concentration to 0.2-0.3 mol per liter, then add 500 kg of unwashed cerium praseodymium carbonate seed crystals through the cerium carbonate seed hopper, and introduce steam through the steam inlet pipe to heat the diluted extracted cerium liquid to 60 degrees Celsius. During the heating process, the driving motor drives the hollow drive shaft to rotate continuously in the forward direction. At this time, due to the limitation of the overrunning clutch, the reciprocating screw does not rotate, and the hollow drive shaft drives the drive tube to rotate the diluted extracted cerium through the hollow drive plate. The feed liquid is continuously stirred; S2, after the stirring is completed, a mixed solution of sodium carbonate and sodium bicarbonate is slowly added to the reaction chamber through the mixed solution inlet pipe. The mixed solution is added at 250 L / H for precipitation in the first hour, and at 300 L / H from the second hour onwards for precipitation. The precipitation time is 4 hours. The driving pipe is continuously stirred during the precipitation process; S3, 600 liters of the extracted cerium feed liquid is added to the reaction chamber through the extracted cerium feed liquid inlet pipe at one time, and steam is continuously introduced through the steam inlet pipe to maintain a constant temperature of 60 degrees Celsius during the precipitation process. Then, the mixed solution is added at a flow rate of 360 L / H until the precipitation is complete; S4, the pH value of the supernatant is checked to be 6.5-7 and REO<0.0005M, which means the precipitation is complete. If the pH value is less than 6.5-7 or the REO is greater than 0.At 0005, continue to add the mixed solution until the precipitation is complete, otherwise add the extracted cerium solution, turn off the stirring after the precipitation is complete and age for eight hours; S5, stir the aged solution through the drive tube, and spread the cerium carbonate praseodymium special filter cloth in the filter tank connected to the output tube, then open the valve on the output tube to allow the solution inside the reaction chamber to enter the filter tank and be filtered by the filter tank, and then smooth the top surface of the filtered cerium carbonate praseodymium precipitate; S6, make the driving motor drive the hollow drive shaft to rotate in the opposite direction, at this time the hollow drive shaft passes through the hollow The driving plate drives the driving tube to rotate in the opposite direction synchronously. When the driving tube rotates in the opposite direction with the hollow driving shaft as the axis, it drives the annular rotating block to rotate in the opposite direction synchronously on the outside of the lifting slider. In addition, at this time, the overrunning clutch no longer restricts the reciprocating screw. The reciprocating screw rotates synchronously with the lifting slider. Therefore, the reciprocating screw starts to drive the lifting slider to descend. When the lifting slider descends, it drives the annular rotating block to descend synchronously. When the annular rotating block descends, it drives the T-shaped slide bar to descend synchronously. When the T-shaped slide bar descends, the pressure on the rotating ring is released, and then the return spring pushes the sealing ring to descend, thereby gradually releasing the pressure. In addition to sealing the water inlet hole; S7, when the annular rotating block descends a distance that reaches a first threshold value, the sealing collar releases the sealing of the water inlet hole, and the pure water inside the water storage chamber enters the hollow drive shaft through the water inlet hole, and then enters the hollow drive plate through the water outlet hole, and then enters the annular rotating block through the telescopic tube, and is sprayed toward the inner wall of the reaction chamber through multiple annular rotating blocks under the action of continuous rotation of the annular rotating block, thereby cleaning the inner wall of the reaction chamber. After the lifting slider drives the annular rotating block to descend to the bottom end of the reciprocating thread outside the reciprocating screw, the lifting slider is lifted. The descending slider drives the annular rotating block to reset. After the annular rotating block resets, it drives the T-shaped slide bar to support the rotating ring, and then the sealing ring closes the water inlet again, thus completing the cleaning process. S8. The cleaning water generated during the cleaning process also enters the filter tank through the output pipe. After cleaning, the valve on the output pipe is closed, and the cerium praseodymium carbonate precipitated in the filter tank is washed with pure water for 3.5 hours. After the washing, the cerium praseodymium carbonate inside the filter tank is drained and then packaged in ton bags. This process is a process for preparing cerium praseodymium carbonate without ammonia nitrogen. Not only is the process complex, but it also requires continuous steam heating during the dilution and precipitation processes. Moreover, the heating temperature during the dilution and precipitation processes is too high, resulting in Cl entrained in the liquid. - The increase leads to a high chloride content in cerium praseodymium carbonate, making it difficult to maintain product quality.

[0005] The paper "Study on the Preparation of Large-Particle Rare Earth Oxides by Ammonium Bicarbonate Precipitation" states that the synthesis conditions for several large-particle cerium carbonates are as follows: when the feed ratio of ammonium bicarbonate to cerium chloride is 3, ① 0.2% by mass of boric acid is added before precipitation to obtain a product with a particle size of about 100 μm; ② 0.5% by mass of triammonium citrate and 0.8% by mass of boric acid are added before precipitation, and the product particle size can also reach 100 μm; ③ 0.5% by mass of triammonium citrate and 0.8% by mass of boric acid are added before precipitation, and the entire feeding and aging process is carried out in a 60°C water bath, and the obtained cerium carbonate particles reach 300 μm; ④ 0.5% by mass of triammonium citrate and 0.8% by mass of boric acid are added before precipitation, and the feeding stage is carried out in a 60°C water bath, followed by aging at room temperature, and the final product particle size is about 400 μm. However, the heating temperature of the precipitation process of this method is too high, and the addition of triammonium citrate and boric acid before precipitation will cause entrained Cl - Increase, the superposition of the two will lead to Cl entrained in the liquid - The large increase in the amount of ammonium bicarbonate leads to a high chloride content in the cerium praseodymium carbonate, making it difficult to maintain product quality. In addition, the addition of ammonium bicarbonate is not conducive to the smooth precipitation reaction of ammonium bicarbonate and cerium chloride during the precipitation process. Summary of the Invention

[0006] The present invention aims to provide a method for preparing high-grade, low-chloride, large-particle crystalline cerium carbonate orthosalt, which uses an ammonium bicarbonate precipitation method without the need for additives. By controlling the main factors affecting precipitation, a large-particle cerium carbonate product is prepared, thereby achieving the purpose of controlling the particle size of the carbonate product.

[0007] To achieve the above objectives, the technical solutions used in the present invention are:

[0008] The method for preparing high-grade, low-chloride, large-particle crystalline cerium carbonate comprises:

[0009] The rare earth concentration of the cerium chloride solution is diluted with pure water to 0.23-0.35 mol / L and the pH value is 2-5;

[0010] Prepare ammonium bicarbonate solution with pure water and control the concentration of ammonium bicarbonate solution to 2.2-2.6 mol / L;

[0011] Add seed crystals of cerium carbonate and ammonium bicarbonate solution to the cerium chloride solution, stir, and perform carbon precipitation reaction at a reaction temperature of 50±2°C;

[0012] The cerium carbonate slurry is rinsed with rinsing water, and large-particle crystalline cerium carbonate is obtained after filtration.

[0013] Furthermore, cerium carbonate seed crystals are added to the diluted liquid, stirring is started at a speed of 140-150 rpm, and ammonium bicarbonate solution is added at a controlled flow rate. The mass of the ammonium bicarbonate solution is 1.45-1.6 times the total amount of rare earth oxides added. During the reaction, the reaction temperature is maintained at 50±2°C. When the pH value reaches 6.5-7.0 at the reaction endpoint, the addition of ammonium bicarbonate solution is stopped, stirring is continued, and aging is carried out for 40-90 minutes. The stirring is stopped after the reaction time is controlled to be 6-7 hours.

[0014] Furthermore, the cerium chloride solution was diluted with pure water to a concentration of 0.3 mol / L and a pH of 3.0, and the ammonium bicarbonate solution was prepared to a concentration of 2.28 mol / L; a certain mass of seed cerium carbonate was added to the cerium chloride solution, and then the ammonium bicarbonate solution was added, the mass of the added ammonium bicarbonate solution was 1.5 times the total amount of rare earth oxides added, the pH value at the reaction end point was 6.8, stirring and aging were continued for 60 minutes, stirring was stopped, and the reaction was allowed to stand. The reaction temperature was maintained at 48°C throughout the reaction process, and the reaction time lasted a total of 6 hours.

[0015] Furthermore, the cerium chloride solution was diluted with pure water to a concentration of 0.27 mol / L and a pH of 4.0, and the concentration of the ammonium bicarbonate solution was 2.10 mol / L; a specified flow rate of ammonium bicarbonate solution was added to the cerium chloride solution, the mass of the added ammonium bicarbonate solution was 1.55 times the total amount of the added rare earth oxides, the stirring speed was controlled at 160-170 rpm, the pH value at the reaction end point was 7.0, stirring and aging were continued for 90 minutes, stirring was stopped, and the reaction was allowed to stand. The reaction temperature was maintained at 50°C throughout the reaction process, and the reaction time lasted a total of 7 hours.

[0016] Furthermore, the cerium chloride solution was diluted with pure water to a rare earth concentration of 0.34 mol / L and a pH of 2.5, and the ammonium bicarbonate solution was prepared to a concentration of 2.40 mol / L; the mass of the ammonium bicarbonate solution added to the cerium chloride solution was 1.53 times the total amount of rare earth oxides added, the stirring speed was controlled at 190-200 rpm, the pH value at the reaction end point was 6.8, stirring was continued for 40 minutes, stirring was stopped, and the reaction was allowed to stand. The reaction temperature was maintained at 51°C throughout the reaction process, and the reaction time lasted a total of 6.5 hours.

[0017] Furthermore, after the rare earth carbonate solution is allowed to stand for 12-32 hours, it is filtered and sampled, and the amount of rinsing water used and the filtration time are controlled.

[0018] Furthermore, the rinsing water is pure water. After the rare earth carbonate solution is allowed to stand for 12-32 hours, it is filtered and sampled. The amount of rinsing water used is 4-6 times the total amount of rare earth oxides. The filtration time is 10-20 minutes, ensuring that the chloride content in the carbonate is ≤0.043% and the rare earth grade is ≥45%.

[0019] Furthermore, the rare earth grade of the cerium carbonate product is 51.96-59.10 wt%, the chloride content is 0.035-1.012 wt%, and the center particle size D50 is 127.8-150.9 μm.

[0020] The technical effects of this application include:

[0021] 1. This application uses cerium chloride solution as raw material in the rare earth production process and adopts ammonium bicarbonate precipitation method without additives. By controlling the main factors affecting precipitation (by controlling the rare earth liquid concentration, feeding method, reaction temperature, precipitant concentration, aging time and other process conditions), a large-particle cerium carbonate product is prepared to achieve the purpose of controlling the particle size of the carbonate product.

[0022] Using ammonium bicarbonate as a precipitant to prepare large-particle cerium carbonate is challenging due to the large amount of gas generated during the reaction, necessitating strict control of precipitation conditions. By studying the effects of process conditions such as rare earth feed concentration, feed method, reaction temperature, precipitant concentration, and aging time on the particle size of the rare earth carbonate, the authors identified the optimal process conditions for preparing large-particle rare earth carbonate. Based on these conditions, the addition of seed crystals (cerium carbonate) guided the formation of large particles.

[0023] The particle size of cerium carbonate prepared by the existing technology is 30-50 μm, while the particle size of cerium carbonate prepared by the present application is about 150 μm, which can achieve controllable particle size of rare earth carbonate products.

[0024] 2. The large-particle carbonate prepared by this application has simple process and operation, requires little equipment investment, and is easy to promote. Furthermore, this application is also suitable for the preparation of other large-particle rare earth carbonates. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 The present invention is a process flow chart of the method for preparing high-grade, low-chloride, large-particle crystalline cerium carbonate. DETAILED DESCRIPTION

[0026] The following description sufficiently illustrates specific embodiments of the invention to enable those skilled in the art to practice and reproduce the invention.

[0027] like Figure 1 The figure shows a process flow chart of the method for preparing high-grade, low-chloride, large-particle crystalline cerium carbonate salt in the present invention.

[0028] The method for preparing high-grade, low-chloride, large-particle crystalline cerium carbonate salt comprises the following specific steps:

[0029] (1) Dilution of feed liquid;

[0030] The rare earth concentration of the cerium chloride solution is diluted with pure water to 0.23-0.35 mol / L, and the pH value is about 2-5.

[0031] (2) Preparation of ammonium bicarbonate solution;

[0032] Prepare ammonium bicarbonate solution with pure water and control the concentration of ammonium bicarbonate solution at 2.2-2.6 mol / L.

[0033] (3) adding seed crystals of cerium carbonate and ammonium bicarbonate solution to the cerium chloride solution to carry out carbon precipitation reaction;

[0034] Add cerium carbonate seed crystals to the diluted liquid, start stirring, and control the flow rate to add ammonium bicarbonate solution. The mass of the ammonium bicarbonate solution is 1.45-1.6 times the total amount of rare earth oxides added. During the reaction, the reaction temperature is maintained at 50±2°C. When the pH value of the reaction endpoint (6.5-7.0) is reached, stop adding ammonium bicarbonate solution, continue stirring, age, and control the reaction time to stop stirring after 6-7 hours.

[0035] The carbon deposition process equation is as follows:

[0036] 2RECl3+6NH4HCO3=RE2(CO3)3↓+3H2O+3CO2↑+6NH4Cl

[0037] Rare earth carbonate precipitation is a complex process with numerous influencing factors. Given the raw and auxiliary materials, precise control of reaction conditions is crucial to producing a product that meets quality standards. Key factors influencing precipitation include precipitant flow distribution, reaction temperature, aging time, stirring speed, and seed crystals.

[0038] Reaction temperature: Properly increasing the system temperature is beneficial to nucleation and crystal growth, but too high a temperature will cause Cl - Increased, difficult to remove by washing.

[0039] Stirring speed: Control the stirring speed at 140-150 rpm. On the one hand, the stirring speed affects the uniformity of precipitation. On the other hand, it is related to the escape rate of CO2 during the precipitation crystallization process. Therefore, moderate stirring is conducive to crystallization.

[0040] Aging time: Aging takes 40-90 minutes. Aging is a process in which small crystals gradually dissolve and large crystals gradually grow. Therefore, appropriately extending the aging time is more conducive to the crystallization of rare earth carbonate.

[0041] Seed crystal: During precipitation, adding a certain amount of carbonate (cerium carbonate) as a seed crystal can induce the formation of rare earth carbonate crystals, which is beneficial to improving product quality.

[0042] (4) washing and filtering the cerium carbonate slurry to obtain large-particle crystalline cerium carbonate;

[0043] After the rare earth carbonate solution has been allowed to stand for 12-32 hours, it is filtered and sampled, and the amount of rinsing water (pure water) used (the amount of rinsing water used is 4-6 times the total amount of rare earth oxides) and the filtration time (10-20 minutes) are controlled to ensure that the chloride content in the carbonate is ≤0.043% and the rare earth grade is ≥45%, which meets the product quality requirements.

[0044] (5) Send samples for analysis.

[0045] Analyze the rare earth content, non-rare earth impurity content and product particle size in carbonates.

[0046] The rare earth grade of the cerium carbonate product is 51.96-59.10%, the chloride content is 0.035-1.012%, and the center particle size D50 is 127.8-150.9 μm.

[0047] Example 1

[0048] (1) Add pure water to dilute the cerium chloride solution to a rare earth concentration of 0.3 mol / L and a pH of 3.0.

[0049] (2) Prepare ammonium bicarbonate solution to a concentration of 2.28 mol / L.

[0050] (3) Add a certain amount of seed crystals of cerium carbonate to the cerium chloride solution, then add a predetermined flow rate of ammonium bicarbonate solution (the mass of the added ammonium bicarbonate solution is 1.5 times the total amount of the added rare earth oxides), control the stirring speed at 140-150 rpm, and continue stirring and aging for 60 minutes until the pH value (6.8) of the reaction endpoint is reached. Stop stirring and let it stand. Maintain the reaction temperature at 48°C throughout the reaction process. The reaction time lasts for a total of 6 hours.

[0051] (4) After standing for 15 hours, the supernatant was poured out, rinsed, and vacuum filtered to obtain the cerium carbonate product.

[0052] (5) The rare earth grade of the cerium carbonate product is 59.10%, the chloride content is 0.035%, and the center particle size D50 is 150.9 μm.

[0053] Example 2

[0054] (1) Add pure water to dilute the cerium chloride solution to a rare earth concentration of 0.27 mol / L and a pH of 4.0.

[0055] (2) Prepare the ammonium carbonate solution to a concentration of 2.10 mol / L.

[0056] (3) Add a specified flow rate of ammonium bicarbonate solution (the mass of the added ammonium bicarbonate solution is 1.55 times the total amount of the added rare earth oxide) to the cerium chloride solution, control the stirring speed at 160-170 rpm, and reach the reaction end point pH value (7.0). Continue stirring and age for 90 minutes, stop stirring, and let it stand. Maintain the reaction temperature at 50°C throughout the reaction process. The reaction time lasts for a total of 7 hours.

[0057] (4) After standing for 12 hours, the supernatant was poured out, rinsed, and vacuum filtered to obtain the cerium carbonate product.

[0058] (5) The rare earth grade of the cerium carbonate product is 52.38%, the chloride content is 0.012%, and the center particle size D50 is 144.1 μm.

[0059] Example 3

[0060] (1) The cerium chloride solution was diluted with pure water to a rare earth concentration of 0.34 mol / L and a pH of 2.5.

[0061] (2) Prepare the ammonium carbonate solution to a concentration of 2.40 mol / L.

[0062] (3) Add a specified flow rate of ammonium bicarbonate solution (the mass of the added ammonium bicarbonate solution is 1.53 times the total amount of the added rare earth oxide) to the cerium chloride solution, control the stirring speed at 190-200 rpm, and continue stirring and aging for 40 minutes until the pH value (6.8) of the reaction endpoint is reached. Then, stop stirring and let the reaction stand. The reaction temperature is maintained at 51°C throughout the reaction process. The reaction time lasts for a total of 6.5 hours.

[0063] (4) After standing for 32 hours, the supernatant was poured out, rinsed, and vacuum filtered to obtain the cerium carbonate product.

[0064] (5) The rare earth grade of the cerium carbonate product is 51.96%, the chloride content is 0.040%, and the center particle size D50 is 127.8 μm.

[0065] The terms used in this invention are descriptive and exemplary, rather than restrictive. Since the present invention can be embodied in a variety of forms without departing from the spirit or essence of the technical solution, it should be understood that the above-described embodiments are not limited to any of the foregoing details, but should be interpreted broadly within the spirit and scope of the appended claims. Therefore, all changes and modifications that fall within the scope of the claims or their equivalents are intended to be covered by the appended claims.

Claims

1. A method for preparing high-grade, low-chloride, large-particle crystalline cerium carbonate, characterized in that: include: The rare earth concentration of the cerium chloride solution is diluted with pure water to 0.23-0.35 mol / L and the pH value is 2-5; Prepare ammonium bicarbonate solution with pure water and control the concentration of ammonium bicarbonate solution to 2.2-2.6 mol / L; Add seed crystals of cerium carbonate and ammonium bicarbonate solution to the cerium chloride solution, stir, and perform carbon precipitation reaction at a reaction temperature of 50±2°C; The cerium carbonate slurry is rinsed with rinsing water, and large-particle crystalline cerium carbonate is obtained after filtration.

2. The method for preparing high-grade, low-chloride, large-particle crystalline cerium carbonate according to claim 1, wherein: Add cerium carbonate seed crystals to the diluted liquid and start stirring at a speed of 140-150 rpm. Control the flow rate of adding ammonium bicarbonate solution. The mass of the ammonium bicarbonate solution is 1.45-1.6 times the total amount of rare earth oxides added. During the reaction, the reaction temperature is maintained at 50±2°C. When the pH value reaches 6.5-7.0 at the reaction endpoint, stop adding ammonium bicarbonate solution, continue stirring, and age for 40-90 minutes. Control the reaction time to stop stirring after 6-7 hours.

3. The method for preparing high-grade, low-chloride, large-particle crystalline cerium carbonate according to claim 2, characterized in that: The cerium chloride solution was diluted with pure water to a concentration of 0.3 mol / L and a pH of 3.0, and the ammonium bicarbonate solution was prepared to a concentration of 2.28 mol / L; a certain mass of seed cerium carbonate was added to the cerium chloride solution, and then the ammonium bicarbonate solution was added, wherein the mass of the added ammonium bicarbonate solution was 1.5 times the total amount of the added rare earth oxides, and the pH value at the reaction end point was 6.

8. The mixture was stirred and aged for 60 minutes, then stirred and allowed to stand. The reaction temperature was maintained at 48°C throughout the reaction process, and the reaction time lasted for a total of 6 hours.

4. The method for preparing high-grade, low-chloride, large-particle crystalline cerium carbonate according to claim 2, wherein: The cerium chloride solution was diluted with pure water to a concentration of 0.27 mol / L and a pH of 4.0, and the concentration of the ammonium bicarbonate solution was 2.10 mol / L. A specified flow rate of ammonium bicarbonate solution was added to the cerium chloride solution, the mass of the added ammonium bicarbonate solution being 1.55 times the total amount of the added rare earth oxides, the stirring speed was controlled at 160-170 rpm, the pH value at the reaction end point was 7.0, stirring was continued for 90 minutes, stirring was stopped, and the reaction was allowed to stand. The reaction temperature was maintained at 50°C throughout the entire reaction process, and the reaction time was a total of 7 hours.

5. The method for preparing high-grade, low-chloride, large-particle crystalline cerium carbonate according to claim 2, characterized in that: The cerium chloride solution was diluted with pure water to a rare earth concentration of 0.34 mol / L and a pH of 2.5, and the ammonium bicarbonate solution was prepared to a concentration of 2.40 mol / L. The mass of the ammonium bicarbonate solution added to the cerium chloride solution was 1.53 times the total amount of the rare earth oxides added. The stirring speed was controlled at 190-200 rpm. The pH value at the reaction end point was 6.

8. Stirring and aging were continued for 40 minutes. Stirring was stopped and the reaction was allowed to stand. The reaction temperature was maintained at 51° C. throughout the reaction process, and the reaction time lasted a total of 6.5 hours.

6. The method for preparing high-grade, low-chloride, large-particle crystalline cerium carbonate according to claim 1, characterized in that: After the rare earth carbonate solution has been allowed to stand for 12-32 hours, it is filtered and sampled, and the amount of rinsing water used and the filtration time are controlled.

7. The method for preparing high-grade, low-chloride, large-particle crystalline cerium carbonate according to claim 1, characterized in that: The rinsing water is pure water. After the rare earth carbonate solution is allowed to stand for 12-32 hours, it is filtered and sampled. The amount of rinsing water used is 4-6 times the total amount of rare earth oxides. The filtration time is 10-20 minutes to ensure that the chloride content in the carbonate is ≤0.043% and the rare earth grade is ≥45%.

8. The method for preparing high-grade, low-chloride, large-particle crystalline cerium carbonate according to claim 1, characterized in that: The rare earth grade of the cerium carbonate product is 51.96-59.10 wt%, the chloride content is 0.035-1.012 wt%, and the center particle diameter D50 is 127.8-150.9 μm.

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