Method for increasing phase transition rate and use of carboxylic acid group-containing substance

Abstract

To provide a method for increasing a phase transition rate that can significantly increase the phase transition rate from rare earth carbonate to basic rare earth carbonate and reduce the content of impurities such as Cl-, SO42-, and NO3-.SOLUTION: A method for increasing a phase transition rate in a process of preparing basic rare earth carbonate from rare earth carbonate comprises the steps of mixing rare earth carbonate and an aqueous solution of a carboxylic acid group-containing substance to obtain a slurry and heating the slurry for reaction.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a method for increasing the phase transition rate during the preparation of basic rare earth carbonates from rare earth carbonates, a method for preparing basic rare earth carbonates from rare earth carbonates, and the use of carboxylic acid group-containing materials. [Background technology]

[0002] Due to their unique properties in light, heat, electricity, magnetism, wear resistance, corrosion resistance, antibacterial properties, etc., rare earth elements are gaining wider application fields and are known as "industrial gold" and "industrial vitamins." The higher the application field, the stricter the quality requirements for purity, particle size, crystal form, type, etc. of rare earth-related products (e.g., rare earth oxides, rare earth fluorides).

[0003] Rare earth carbonates and basic rare earth carbonates are precursor compounds for forming rare earth-related products such as rare earth oxides and rare earth fluorides. Rare earth carbonates and basic rare earth carbonates are obtained by precipitating rare earth solutions (e.g., rare earth chloride solutions, rare earth nitrate solutions, or rare earth sulfate solutions). However, (1) during the process of precipitating rare earth carbonates or basic rare earth carbonates from rare earth solutions, for example, Cl - , SO4 2- , NO3 - The acid anions in rare earth solution systems such as those mentioned above remain in the rare earth carbonate or basic rare earth carbonate in various forms, becoming impurities in downstream functional materials and adversely affecting the performance of these materials. Another issue is that (1) it is difficult to control the particle size of the rare earth carbonate or basic rare earth carbonate during the process of precipitating the rare earth solution using conventional equipment, making it difficult to obtain rare earth compounds with a particle size of 5 μm or less.

[0004] CN104310456A discloses a method for producing rare earth carbonate. Rare earth chloride and carbonate solution are fed into a specific precipitation reactor in parallel, and the aging time of the rare earth carbonate is controlled by controlling the feed and discharge rates. This achieves spatial separation between the reaction zone and the crystallization zone, allowing fine-grained, low-chlorine rare earth carbonate products to be directly precipitated from a hydrochloric acid medium. Although this method results in a chlorine content of less than 50 ppm and a small particle size, it requires special equipment.

[0005] CN115849429A discloses a method for preparing lanthanum carbonate tetrahydrate. Excess hydrochloric acid is reacted with lanthanum oxide to prepare a mixed solution of hydrochloric acid and lanthanum chloride. This mixed solution is then transferred to a sealed reaction vessel, and sodium bicarbonate solution is gradually added to the reaction vessel. The release of carbon dioxide generated during the neutralization reaction is controlled, and the reaction is carried out in a carbon dioxide-rich positive pressure environment while maintaining a positive pressure of 100-1000 Pa within the reaction vessel. After the reaction is complete, the reaction is filtered and washed with water to obtain a wet lanthanum carbonate octahydrate. The wet lanthanum carbonate octahydrate is then dried to obtain lanthanum carbonate tetrahydrate, which has a high chloride ion content and is D 50 is 6 to 10 μm, which is somewhat large.

[0006] Acid anions (e.g., Cl) obtained during the precipitation of rare earth solutions - , SO4 2- , NO3 - For rare earth carbonates that contain high amounts (e.g., 100 ppm or more) of acid anions and have large particle sizes, how to treat them to reduce the acid anion content and enable smaller particle sizes is a technical issue that must be resolved as soon as possible.

[0007] CN103708525A discloses a method for producing low-chlorine rare earth carbonates and oxides. Rare earth carbonate is placed in a hot alkaline solution with a pH of 7 or higher and a temperature of 80°C or higher, and reacted for 30 minutes or more at a liquid-to-solid ratio of 1:1 to 50:1 and an alkali to rare earth molar ratio of 0.5:1 to 1.1:1. The basic rare earth carbonate obtained by this method still has a large particle size and a high chloride content. Summary of the Invention

[0008] In view of the above problems, one object of the present invention is to significantly increase the phase transition rate from rare earth carbonate to basic rare earth carbonate, and - , SO4 2- and NO3 - Another object of the present invention is to provide a method for increasing the phase transformation rate, which can significantly reduce the content of impurities such as ammonium hydroxide, ammonium nitrate, etc. Another object of the present invention is to provide a method for preparing basic rare earth carbonates from rare earth carbonates.

[0009] Another object of the present invention is to provide uses for carboxylic acid group-containing materials.

[0010] The present invention achieves the above object with the following configuration.

[0011] In one aspect, the present invention provides a method for producing a pharmaceutical composition comprising: mixing a rare earth carbonate and an aqueous solution of a carboxylic acid group-containing substance to obtain a slurry; heating the slurry to react; The present invention provides a method for increasing the phase transition rate during the preparation of a basic rare earth carbonate from a rare earth carbonate containing

[0012] In another aspect, the present invention provides a method for producing a pharmaceutical composition comprising: mixing a rare earth carbonate with an aqueous solution of a carboxylic acid group-containing substance to obtain a slurry; heating the slurry to react and obtain an intermediate product; and converting the intermediate product into basic rare earth carbonate crystals, basic rare earth carbonate clusters, or a mixture of basic rare earth carbonate crystals and basic rare earth carbonate clusters; Further provided is a method for preparing a basic rare earth carbonate from a rare earth carbonate comprising:

[0013] According to the method of the present invention, preferably, the carboxylic acid group-containing substance is (1) C1 to C6 monocarboxylic acid, or (2) A mixture of a C1-C6 monocarboxylic acid and a C1-C6 monocarboxylic acid ammonium salt, It is selected from.

[0014] According to the method of the present invention, preferably the C1 to C6 monocarboxylic acid is one or more selected from formic acid, acetic acid, and propionic acid; The mixture of a C1-C6 monocarboxylic acid and a C1-C6 monocarboxylic acid ammonium salt is selected from a mixture of formic acid and ammonium formate, a mixture of acetic acid and ammonium acetate, or a mixture of propionic acid and ammonium propionate.

[0015] According to the method of the present invention, preferably the amount of the carboxylic acid group-containing substance used is 1 to 9% of the theoretical number of moles required for the complex formation reaction between the carboxylic acid group-containing substance and the rare earth element in the rare earth carbonate; The concentration of the carboxylic acid group-containing substance in the aqueous solution of the carboxylic acid group-containing substance is 0.015 to 0.15 mol / L.

[0016] According to the method of the present invention, the slurry is preferably heated to 50 to 100° C. and reacted for 10 to 600 minutes.

[0017] According to the method of the present invention, preferably The method includes the steps of converting the intermediate product into basic rare earth carbonate crystals, basic rare earth carbonate clusters, or a mixture of basic rare earth carbonate crystals and basic rare earth carbonate clusters, followed by solid-liquid separation, and recycling the resulting filtrate as an aqueous solution of a carboxylic acid group-containing substance.

[0018] According to the method of the present invention, preferably Cl in rare earth carbonates - , SO4 2- and NO3 - The total content of exceeds 120 ppm, and Cl in basic rare earth carbonate - , SO4 2- and NO3- The total content of is 50 ppm or less, Average particle size D of basic rare earth carbonate 50 is less than 5.5 μm.

[0019] In another aspect, the present invention provides the use of a carboxylic acid group-containing substance for increasing the phase transition rate in the process of preparing a basic rare earth carbonate from a rare earth carbonate.

[0020] According to the use of the present invention, preferably, the carboxylic acid group-containing substance is (1) C1 to C6 monocarboxylic acid, or (2) A mixture of a C1-C6 monocarboxylic acid and a C1-C6 monocarboxylic acid ammonium salt, It is selected from.

[0021] The method of the present invention can increase the phase transition rate when preparing a basic rare earth carbonate from a rare earth carbonate. Furthermore, the present invention can also increase the rate of the phase transition when preparing a basic rare earth carbonate from an acid anion (e.g., Cl). - , SO4 2- and NO3 - The present invention can convert rare earth carbonates containing high amounts of carboxylic acid groups (such as carboxylic acid groups) and large particle sizes into basic rare earth carbonates containing low amounts of acid anions and small particle sizes. The total acid anion content is reduced from 200 ppm or more to 50 ppm or less. The carboxylic acid group-containing materials of the present invention can be used in small amounts and recycled, making them low-cost and environmentally friendly. Compared to traditional hydrothermal conversion methods, which require high energy consumption, the present invention has the advantages of high speed, low energy consumption, simple process, and ease of industrial production. Furthermore, the present invention allows for process control and can convert rare earth carbonates into basic rare earth carbonate crystals, basic rare earth carbonate clusters, or a mixture of basic rare earth carbonate crystals and basic rare earth carbonate clusters. [Brief explanation of the drawings]

[0022] [Figure 1] FIG. 1 is an SEM image of basic lanthanum carbonate obtained in Example 1 of the present invention. [Figure 2] FIG. 1 is an XRD diagram of basic lanthanum carbonate obtained in Example 1 of the present invention. [Figure 3] FIG. 1 is an XRD diagram of basic cerium carbonate obtained in Example 2 of the present invention. [Figure 4] FIG. 1 is an XRD diagram of cerium carbonate octahydrate used as a raw material in Example 2 of the present invention. [Figure 5] FIG. 1 is an SEM image of the praseodymium neodymium basic carbonate obtained in Example 3 of the present invention. [Figure 6] FIG. 1 is an XRD diagram of basic europium carbonate obtained in Example 6 of the present invention. [Figure 7] FIG. 1 is an SEM image of basic europium carbonate obtained in Example 6 of the present invention. [Figure 8] FIG. 1 is an SEM image of the product obtained in Comparative Example 1. [Figure 9] 1 is an XRD diagram of the intermediate product and the product in Comparative Example 1. [Figure 10] FIG. 1 is an SEM image of the product obtained in Comparative Example 2. [Figure 11] 10 is an XRD diagram of the intermediate product and the product in Comparative Example 2. DETAILED DESCRIPTION OF THE INVENTION

[0023] The present invention will be further described below with reference to specific examples, but the scope of protection of the present invention is not limited thereto.

[0024] In the present invention, Cm to Cn represent that the compound has m to n carbon atoms, and for example, a C1 to C6 monocarboxylic acid represents a monocarboxylic acid having 1 to 6 carbon atoms.

[0025] "D" in the present invention 50" is the median diameter or median particle diameter, and indicates the particle diameter corresponding to when the cumulative particle size distribution percentage of a sample reaches 50%. In a physical sense, particles with a particle diameter larger than that account for 50%, and particles smaller than that also account for 50%.

[0026] The present invention provides a method for increasing the phase transition rate during the preparation of a basic rare earth carbonate from a rare earth carbonate, which comprises (1) a mixing step and (2) a reaction step. Preferably, the method further comprises (3) a conversion step. The present invention provides a method for preparing a basic rare earth carbonate from a rare earth carbonate, which comprises (1) a mixing step, (2) a reaction step, and (3) a conversion step. This method is described in detail below.

[0027] <Mixing step> A slurry is obtained by mixing a rare earth carbonate with an aqueous solution of a carboxylic acid group-containing substance. This is advantageous for increasing the phase transition rate and for obtaining a basic rare earth carbonate with a reduced acid anion content and small particle size.

[0028] In the present invention, the rare earth element RE in the rare earth carbonate may be one or more of the elements La to Gd in ascending order of atomic number, including lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), lutetium (Lu), scandium (Sc), and yttrium (Y). Preferably, the rare earth element RE is lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), promethium (Pm), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), lutetium (Lu), scandium (Sc) and yttrium (Y). Preferably, the rare earth element RE is one or more selected from lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), samarium (Sm), europium (Eu) and gadolinium (Gd). More preferably, the rare earth element RE is one or more elements selected from lanthanum (La), cerium (Ce), and samarium (Sm). This is advantageous for obtaining basic rare earth carbonate nanocrystals and reducing the particle size of the basic rare earth carbonate. More preferably, the rare earth element RE is lanthanum (La). This is advantageous for obtaining nano-sized basic rare earth carbonate.

[0029] Cl in rare earth carbonates - , SO4 2- and NO3 - The total content of rare earth carbonates is more than 120 ppm, preferably more than 150 ppm, and more preferably more than 200 ppm. 50 Such rare earth carbonates have a smaller particle size and a Cl content of 45 μm or more after being treated by the method of the present invention. - , SO4 2- and NO3 -It is advantageous to obtain a basic rare earth carbonate having a total content of 50 ppm or less.

[0030] In the present invention, the rare earth carbonate (i.e., rare earth carbonate) may be a rare earth carbonate solid powder that does not contain water of crystallization, or may be a rare earth carbonate that contains water of crystallization. Many rare earth carbonates contain water of crystallization.

[0031] In the present invention, the carboxylic acid group-containing substance in the aqueous solution of the carboxylic acid group-containing substance is (1) C1 to C6 monocarboxylic acid, or (2) A mixture of C1-C6 monocarboxylic acid and C1-C6 monocarboxylic acid ammonium salt It is selected from.

[0032] In some specific embodiments, the carboxylic acid group-containing substance is selected from C1 to C6 monocarboxylic acids. In other specific embodiments, the carboxylic acid group-containing substance is selected from a mixture of C1 to C6 monocarboxylic acids and their ammonium salts.

[0033] Examples of C1-C6 monocarboxylic acids include, but are not limited to, formic acid, acetic acid, propionic acid, n-butyric acid, isobutyric acid, n-valeric acid, and n-hexanoic acid. In some specific embodiments, the carboxylic acid group-containing substance is one or more selected from formic acid, acetic acid, propionic acid, and n-butyric acid. Preferably, the carboxylic acid group-containing substance is acetic acid. This is advantageous for obtaining nanosized basic rare earth carbonates.

[0034] In some other specific embodiments, the carboxylic acid group-containing substance is a mixture of one or more selected from the group consisting of a mixture of formic acid and ammonium formate, a mixture of acetic acid and ammonium acetate, a mixture of propionic acid and ammonium propionate, and a mixture of n-butyric acid and ammonium n-butyrate. The carboxylic acid group-containing substance is preferably a mixture of acetic acid and ammonium acetate. This is advantageous for obtaining basic rare earth carbonate nanocrystals and reducing the particle size of the basic rare earth carbonate.

[0035] In the present invention, the molar ratio of the C1 to C6 monocarboxylic acid to the corresponding ammonium salt is not limited and may be, for example, 10 to 1:1, specifically 10:1, 9:1, 8:1, 7:1, 6:1, 5:1, 4:1, 3:1, 2:1, or 1:1.

[0036] Rare earth carbonates are hydrolyzed in hot aqueous solutions to form RE 3+ and H2O bond is [RE(OH)(H2O) n-1 ] 2+ exists as CO3 2- The ion is [RE(OH)(HO) n-1 ] 2+ It has been found in the present invention that when it collides with, it reacts to produce RECO3OH.

[0037] When a substance containing a carboxylic acid group is added to the reaction system, the substance containing a carboxylic acid group first reacts with the rare earth carbonate, and the temperature rises, promoting the ionization of the carboxylic acid, resulting in the formation of more H + The carbonic acid produced by dissolving CO2 in water is released, accelerating the dissolution of rare earth carbonates. 2- and H + This produces more rare earth carbonate, dissolving it faster and increasing the amount of RE 3+ Ions and CO3 2- produces CO3 2- The ion is [RE(OH)(HO) n-1 ] 2+ When it collides with , a reaction occurs to form RECO3OH, which increases the rate of the phase transition from rare earth carbonate to basic rare earth carbonate.

[0038] Although the principle is not clear, the reaction is thought to be as shown in formulas (1) to (5).

[0039] The present inventors have found that the phase transition rate of rare earth carbonates can be increased by 50 to 200% using an aqueous solution of a carboxylic acid group-containing substance, compared to a pure aqueous solution under the same conditions. By changing the morphology and particle size level, impurities present in the encapsulated and entrained state, especially Cl, can be reduced. - , SO4 2- and NO3 - These impurities are released, resulting in the effect of reducing the impurities.

[0040] It has also been found in the present invention that acetic acid can also function as a dispersant and effectively inhibit aggregation of basic rare earth carbonates.

[0041] The aqueous solution of the carboxylic acid group-containing substance according to the present invention has a concentration of 0.015 to 0.15 mol / L, preferably 0.03 to 0.15 mol / L, and more preferably 0.05 to 0.135 mol / L. The amount of the carboxylic acid group-containing substance used in the aqueous solution is 1 to 9%, preferably 2 to 9%, and more preferably 3 to 8% of the theoretical number of moles required for the complex formation reaction between the carboxylic acid group-containing substance and the rare earth element in the rare earth carbonate. The present invention involves mixing a solid rare earth carbonate with an aqueous solution of the carboxylic acid group-containing substance to obtain a slurry. This increases the phase transition rate, advantageously obtaining a basic rare earth carbonate with a smaller particle size and reducing the acid anion content.

[0042] <Reaction steps and conversion steps> The slurry is heated to react and form an intermediate product, which is advantageous for increasing the rate of phase transformation, and then heated to convert the intermediate product into basic rare earth carbonate crystals, basic rare earth carbonate clusters, or a mixture of basic rare earth carbonate crystals and basic rare earth carbonate clusters.

[0043] The temperature of the reaction step and the conversion step may be 50 to 100°C, preferably 60 to 95°C, and more preferably 70 to 90°C. The total time of the reaction step and the conversion step may be 10 to 600 minutes, preferably 20 to 300 minutes, and more preferably 30 to 200 minutes. In some embodiments, the time of the reaction step may be 10 to 90 minutes, preferably 20 to 80 minutes, and more preferably 30 to 60 minutes. The time of the conversion step may be 50 to 300 minutes, preferably 60 to 200 minutes, and more preferably 70 to 100 minutes.

[0044] Stirring is required in the reaction step and the conversion step. The stirring speed is 150 to 1000 rpm, preferably 200 to 800 rpm, more preferably 250 to 700 rpm, and even more preferably 300 to 600 rpm. This is advantageous in increasing the phase transition rate, obtaining a basic rare earth carbonate with a smaller particle size, and also reducing Cl. - , SO4 2- and NO3 - This is advantageous in reducing the content of impurities such as

[0045] The intermediate product is converted into basic rare earth carbonate crystals, basic rare earth carbonate clusters, or a mixture of basic rare earth carbonate crystals and basic rare earth carbonate clusters, followed by solid-liquid separation, and the resulting filtrate is recycled as an aqueous solution of a carboxylic acid group-containing substance, thereby obtaining basic rare earth carbonate and recycling the filtrate, thereby reducing the generation of waste liquid.

[0046] The solid-liquid separation may be performed by centrifugation or filtration, preferably filtration. Filtration yields a filter cake and a filtrate. The filtrate is recycled as an aqueous solution of the carboxylic acid group-containing substance, and additional carboxylic acid group-containing substance can be added as needed. The separated solid is washed with water and dried to obtain a basic rare earth carbonate product. The basic rare earth carbonate product may be basic rare earth carbonate crystals, basic rare earth carbonate clusters, or a mixture of basic rare earth carbonate crystals and basic rare earth carbonate clusters.

[0047] Cl in basic rare earth carbonate prepared by the method of the present invention - , SO4 2- and NO3 - The total content of is 50 ppm or less, and the average particle diameter D 50 is less than 5.5 μm. 50 is less than 5.5 μm, preferably 5 μm or less than 5 μm.

[0048] According to one embodiment of the present invention, a method for preparing a basic rare earth carbonate from a rare earth carbonate comprises: Cl - , SO4 2- and NO3 - The total content of exceeds 200 ppm and the average particle diameter D 50 providing a rare earth carbonate having a particle size of 45 μm or greater; and preparing an aqueous solution of a carboxylic acid group-containing substance having a molar concentration of 0.015 to 0.15 mol / L.

[0049] The rare earth carbonate is added to an aqueous solution of a carboxylic acid group-containing substance and mixed (the amount of the carboxylic acid group-containing substance used is 1 to 9% of the theoretical number of moles required for the complex formation reaction between the carboxylic acid group-containing substance and the rare earth element in the rare earth carbonate). This gives a slurry. The slurry is heated to 70 to 100°C and reacted for 10 to 90 minutes at a stirring speed of 150 to 500 rpm and a temperature of 70 to 100°C to give an intermediate product. The intermediate product is then converted for 50 to 300 minutes at a stirring speed of 150 to 500 rpm and a temperature of 70 to 100°C. The filter cake and filtrate are obtained by filtration. The filtrate is stored for recycling. The filter cake is washed with water, dried, and polished to remove Cl. - , SO4 2- and NO3 - The total content of is 50 ppm or less, and the average particle diameter D 50 The resulting basic rare earth carbonate is a basic rare earth carbonate crystal, a basic rare earth carbonate cluster, or a mixture of basic rare earth carbonate crystals and basic rare earth carbonate clusters.

[0050] <Use of substances containing carboxylic acid groups> The present invention has discovered that an aqueous solution of a carboxylic acid group-containing substance first reacts with a portion of the rare earth carbonate to form a rare earth complex, in which the rare earth element exists as an ion in the solution. The carboxylic acid group-containing substance promotes hydrolysis of the rare earth carbonate, allowing more carbonate groups and rare earth ions to directly participate in the production of basic rare earth carbonate, thereby increasing the phase transition rate of the rare earth carbonate. The phase transition rate can be increased by 50 to 200% compared to a pure aqueous solution under the same conditions. The so-called phase transition refers to the conversion of one form of rare earth carbonate to another form of basic rare earth carbonate. During the above process, the roughly spherical, large-sized particles of rare earth carbonate are successively crushed and converted into small, spindle-shaped particles of basic rare earth carbonate, each existing as one or more of nanoclusters and nanocrystalline particles. The present invention has discovered that the impurities (e.g., chloride ions, nitrate ions, sulfate ions, etc.) present in the encapsulated and entrained state are released, thereby achieving the goal of reducing the aforementioned impurities.

[0051] Thus, the present invention further provides the use of a carboxylic acid group-containing substance to increase the phase transition rate during the preparation of a basic rare earth carbonate from a rare earth carbonate. The use includes (1) a mixing step, (2) a reaction step, and preferably further includes (3) a conversion step. The specific steps and substance selection are as described above, and will not be described here.

[0052] The measurement method is explained below.

[0053] Measurement of chloride ion content: Measured by mercury thiocyanate spectrophotometer method using T6 New Century type ultraviolet-visible spectrophotometer.

[0054] Measurement of sulfate ion and nitrate ion content: Measured using Agilent 5800 inductively coupled plasma mass spectrometer.

[0055] SEM measurement: Sigma-500 type scanning electron microscope (FESEM) was used for measurement.

[0056] XRD measurement: Measurement is performed using a D8ADVANE type X-ray diffractometer (XRD) manufactured by Bruker, Germany.

[0057] Particle size distribution: Measured and analyzed using a Bettersize2600 laser particle size distribution analyzer using a wet measurement method.

[0058] Example 1 Cl - Content 360ppm, particle size D 50 Provide 500g of 65µm lanthanum carbonate solids, Prepare an acetic acid solution (aqueous solution of a carboxylic acid group-containing substance) with a molar concentration of 0.125 mol / L. The lanthanum carbonate solid was added to an acetic acid solution and mixed (the amount of acetic acid used in the acetic acid solution was 7% of the theoretical number of moles required for the complex formation reaction between acetic acid and lanthanum element in lanthanum carbonate) to obtain a slurry. The slurry was heated to 70°C and reacted for 60 minutes at a stirring speed of 300 rpm and a temperature of 70°C to obtain basic lanthanum carbonate nanoclusters. After reacting for 120 minutes, basic lanthanum carbonate nanocrystalline particles were obtained. The resulting particles were filtered to obtain a filter cake and a filtrate. The filtrate was left as is for recycling. The filter cake was washed with water, dried at 60°C for 4 hours, and polished to obtain a particle diameter D 50 0.087 μm, Cl - A nanocrystalline basic lanthanum carbonate with a content of 45 ppm was obtained.

[0059] The SEM image of the obtained basic lanthanum carbonate is shown in FIG. 1, and the XRD image is shown in FIG.

[0060] Example 2 Cl - Content 320ppm, particle size D 50 Provide 500 g of 59 μm cerium carbonate solid (cerium carbonate octahydrate), A mixed solution of acetic acid and ammonium acetate (aqueous solution of a carboxylic acid group-containing substance) is prepared, wherein the molar concentration of acetic acid in the mixed solution is 0.05 mol / L and the molar concentration of ammonium acetate is 0.01 mol / L; The cerium carbonate solid was added to a mixed solution of acetic acid and ammonium acetate and mixed (the amount of acetic acid used was 5% of the theoretical number of moles required for the complex formation reaction between acetic acid and cerium element in cerium carbonate, and the amount of ammonium acetate used was 1% of the theoretical number of moles required for the complex formation reaction between ammonium acetate and cerium element in cerium carbonate) to obtain a slurry. The slurry was heated to 80°C and reacted for 20 minutes at a stirring speed of 300 rpm and a temperature of 80°C. In this case, cerium carbonate tetrahydrate was obtained. After reacting for 60 minutes, basic cerium carbonate nanoclusters were obtained. After reacting for 120 minutes, basic cerium carbonate nanocrystalline particles were obtained. The obtained particles were filtered to obtain a filter cake and a filtrate. The filtrate was stored and reused. The filter cake was washed with water, dried at 60°C for 4 hours, and polished to obtain a particle diameter D 50 0.32 μm, Cl - Basic cerium carbonate was obtained as nanocrystalline particles with a content of 25 ppm.

[0061] The XRD results of the obtained basic cerium carbonate are shown in FIG. 3, and the XRD of the raw material cerium carbonate is shown in FIG.

[0062] Example 3 SO4 2- Content 320ppm, particle size D 50 We provide 500g of 54μm Praseodymium Neodymium Carbonate solids, A mixture solution of propionic acid and ammonium propionate (used as an aqueous solution of a carboxylic acid group-containing substance) is prepared, wherein the molar concentration of propionic acid in the mixture solution is 0.03 mol / L and the molar concentration of ammonium propionate is 0.01 mol / L; The praseodymium neodymium carbonate solid was added to a mixture solution of propionic acid and ammonium propionate, and mixed (the amount of propionic acid used was 3% of the theoretical number of moles required for the complex formation reaction between propionic acid and praseodymium neodymium element in the praseodymium neodymium carbonate, and the amount of ammonium propionate used was 1% of the theoretical number of moles required for the complex formation reaction between ammonium propionate and praseodymium neodymium element in the praseodymium neodymium carbonate). A slurry was obtained, and the slurry was heated to 90°C and reacted for 160 minutes under conditions of a stirring speed of 300 rpm and a temperature of 90°C to obtain basic praseodymium neodymium carbonate nanoclusters. The nanoclusters were filtered to obtain a filter cake and a filtrate. The filtrate was left as it was for recycling. The filter cake was washed with water, and the washed filter cake was dried at 60°C for 4 hours and polished to obtain a particle diameter D 50 0.64μm, SO4 2- A nanocluster of praseodymium neodymium basic carbonate with a content of 40 ppm was obtained.

[0063] The SEM image of the obtained praseodymium neodymium basic carbonate is shown in FIG.

[0064] Example 4 Cl - Content 360ppm, particle size D 50 Provide 250 g of 65 μm lanthanum carbonate solid and add Cl - Content 320ppm, particle size D 50 Provide 250 g of 59 μm cerium carbonate solids, A propionic acid solution (aqueous solution of a carboxylic acid group-containing substance) with a molar concentration of 0.09 mol / L is prepared. Lanthanum carbonate and cerium carbonate were added to a propionic acid solution and mixed (the amount of propionic acid used was 9% of the theoretical number of moles required for the complex formation reaction between propionic acid and the lanthanum and cerium elements in lanthanum carbonate and cerium carbonate). This gave a slurry, which was heated to 90°C and reacted for 160 minutes at a stirring speed of 300 rpm and a temperature of 90°C to give basic lanthanum cerium carbonate nanoclusters. This was then filtered to give a filter cake and filtrate. The filtrate was left as is for recycling, and the filter cake was washed with water. The washed filter cake was dried at 60°C for 4 hours and polished to obtain a particle diameter D 50 2.64μm, SO4 2- A nanocluster of basic lanthanum cerium carbonate with a content of 40 ppm was obtained.

[0065] Example 5 No. 3 - Content 290ppm, particle size D 50 Provide 500 g of 45 μm samarium carbonate solid, A formic acid solution (aqueous solution of a carboxylic acid group-containing substance) with a molar concentration of 0.05 mol / L is prepared. Samarium carbonate was added to the formic acid solution and mixed (the amount of formic acid used was 9% of the theoretical number of moles required for the complex formation reaction between formic acid and the samarium element in samarium carbonate) to obtain a slurry. The slurry was heated to 100°C and reacted for 300 minutes at a stirring speed of 300 rpm and a temperature of 100°C to obtain basic samarium carbonate nanoclusters. This was then filtered to obtain a filter cake and filtrate. The filtrate was left as is for recycling. The filter cake was washed with water, and the washed filter cake was dried at 60°C for 4 hours and polished to obtain a particle diameter D 50 3.4μm, NO3 - A nanocluster of basic samarium carbonate with a content of 35 ppm was obtained.

[0066] Example 6 No. 3 - Content 240ppm, particle size D 50 Provide 500g of 53μm europium carbonate solid, A mixed solution of formic acid, acetic acid, and propionic acid (aqueous solution of a carboxylic acid group-containing substance) was prepared, wherein the molar concentrations of formic acid, acetic acid, and propionic acid were all 0.01 mol / L; Europium carbonate was added to a mixed solution of formic acid, acetic acid, and propionic acid, and mixed (the amount of formic acid used was 3% of the theoretical number of moles required for the complex formation reaction between formic acid and europium element in europium carbonate, the amount of acetic acid used was 3% of the theoretical number of moles required for the complex formation reaction between acetic acid and europium element in europium carbonate, and the amount of propionic acid used was 3% of the theoretical number of moles required for the complex formation reaction between propionic acid and europium element in europium carbonate). A slurry was obtained, and the slurry was heated to 95°C and reacted at a stirring speed of 300 rpm for 400 minutes at 95°C to convert the europium carbonate into basic europium carbonate nanoclusters. The mixture was filtered to obtain a filter cake and a filtrate. The filtrate was left as is for recycling. The filter cake was washed with water, and the washed filter cake was dried at 60°C for 4 hours and polished to obtain a particle diameter D 50 4.2μm, NO3 - Basic europium carbonate was obtained as nanoclusters with a content of less than 50 ppm.

[0067] The XRD and SEM results of the obtained basic europium carbonate are shown in Figures 6 and 7, respectively.

[0068] Example 7 Cl - Content 280ppm, particle size D 50 providing 56 μm gadolinium carbonate solid 500; A mixed solution of formic acid, ammonium formate, acetic acid, and ammonium acetate (aqueous solution of a carboxylic acid group-containing substance) was prepared, in which the molar concentrations of formic acid and ammonium formate were each 0.05 mol / L, and the molar concentrations of acetic acid and ammonium acetate were each 0.03 mol / L. Gadolinium carbonate was added to the aqueous solution of the carboxylic acid group-containing substance and mixed (the total number of moles of formic acid and ammonium formate was 5% of the theoretical number of moles required for the complex formation reaction between formic acid and gadolinium element in gadolinium carbonate, and the molar ratio of formic acid to ammonium formate was 5:1; the total number of moles of acetic acid and ammonium acetate was 3% of the theoretical number of moles required for the complex formation reaction between acetic acid and gadolinium element in gadolinium carbonate, and the molar ratio of acetic acid to ammonium acetate was 5:1) to obtain a slurry. The slurry was heated to 95°C and reacted at a stirring speed of 300 rpm for 600 minutes at 95°C to convert the gadolinium carbonate into a mixture of basic gadolinium carbonate nanoclusters and nanocrystalline particles. The mixture was filtered to obtain a filter cake and a filtrate. The filtrate was left as is for recycling. The filter cake was washed with water, and the washed filter cake was dried at 60°C for 4 hours and polished to obtain a particle diameter D 50 4.6 μm, Cl - A mixture of nanoclusters and nanocrystalline particles of basic gadolinium carbonate with a content of 42 ppm was obtained.

[0069] Example 8 Cl - Content 320ppm, particle size D 50 Provide 200g of 59μm cerium carbonate solid, NO3 - Content 290ppm, particle size D 50 300 g of 45 μm samarium carbonate solid was provided.

[0070] A mixed solution of propionic acid, ammonium propionate, acetic acid, and ammonium acetate (aqueous solution of a carboxylic acid group-containing substance) was prepared, in which the molar concentrations of propionic acid and ammonium propionate were each 0.15 mol / L, and the molar concentrations of acetic acid and ammonium acetate were each 0.015 mol / L.

[0071] Cerium carbonate and samarium carbonate were added to the aqueous solution of the carboxylic acid group-containing substance and mixed (the total number of moles of propionic acid and ammonium propionate was 9% of the theoretical number of moles required for the complex formation reaction between propionic acid and samarium carbonate and between cerium and samarium in cerium carbonate, the molar ratio of propionic acid to ammonium propionate was 3:1, the total number of moles of acetic acid and ammonium acetate was 1% of the theoretical number of moles required for the complex formation reaction between acetic acid and cerium and samarium, the molar ratio of acetic acid to ammonium acetate was 3:1), to obtain a slurry. The slurry was heated to 90°C and reacted for 450 minutes at a stirring speed of 300 rpm and a temperature of 90°C to convert the cerium carbonate and samarium carbonate into basic cerium samarium carbonate nanocrystalline particles, which were then filtered to obtain a filter cake and a filtrate. The filtrate was left as is for recycling, and the filter cake was washed with water. The washed filter cake was dried at 60°C for 4 hours and polished to obtain a particle diameter D 50 0.64 μm, Cl - and NO3 - The basic cerium samarium carbonate was obtained as nanocrystalline particles having a total content of less than 50 ppm.

[0072] Comparison 1 This comparative example differed from Example 2 in that no aqueous solution of a carboxylic acid group-containing substance was added.

[0073] Specifically, solid cerium carbonate was added to pure water to obtain a slurry, and the other reaction conditions were the same as in Example 2. After 20 minutes of reaction, the cerium carbonate was not completely converted. After 120 minutes of reaction, a mixture of cerium carbonate and basic cerium carbonate was obtained. After 180 minutes of reaction, basic cerium carbonate in the form of micron clusters was obtained. This was filtered to obtain a filter cake and filtrate. The filtrate was left as is for recycling. The filter cake was washed with water and then dried at 60°C for 4 hours to obtain a particle diameter D 50 12.54 μm, Cl - A basic cerium carbonate containing 85 ppm was obtained.

[0074] The SEM image of the obtained basic cerium carbonate is shown in Figure 8. The XRD images of the raw material, intermediate product, and product are shown in Figure 9.

[0075] Comparison 2 This comparative example differed from Example 6 in that no aqueous solution of a carboxylic acid group-containing substance was added.

[0076] Specifically, europium carbonate solid was added to pure water to obtain a slurry, and the other reaction conditions were the same as in Example 6. After 400 minutes of reaction, the europium carbonate was not completely converted, and a mixture of europium carbonate and basic europium carbonate was obtained. This was then filtered to obtain a filter cake and filtrate. The filtrate was then left for recycling. The filter cake was washed with water and dried at 60°C for 4 hours to obtain microspheres with a particle size of D. 50 46μm, NO3 - A mixture of europium carbonate and basic europium carbonate with a content of 215 ppm was obtained.

[0077] The SEM image of the obtained product is shown in Figure 10. The XRD images of the intermediate product and the reaction product are shown in Figure 11.

[0078] The present invention is not limited to the above-described embodiments, and all modifications, improvements, and substitutions that come to mind by those skilled in the art are included within the scope of the present invention, provided that they do not deviate from the spirit of the present invention.

Claims

1. mixing a rare earth carbonate and an aqueous solution of a carboxylic acid group-containing substance to obtain a slurry; heating the slurry to react; A method for increasing the phase transition rate during the preparation of a basic rare earth carbonate from a rare earth carbonate, comprising:

2. mixing a rare earth carbonate with an aqueous solution of a carboxylic acid group-containing substance to obtain a slurry; heating the slurry to react and obtain an intermediate product; and converting the intermediate product into basic rare earth carbonate crystals, basic rare earth carbonate clusters, or a mixture of basic rare earth carbonate crystals and basic rare earth carbonate clusters; A method for preparing a basic rare earth carbonate from a rare earth carbonate, comprising:

3. The carboxylic acid group-containing substance is (1) C1 to C6 monocarboxylic acid, or (2) A mixture of a C1-C6 monocarboxylic acid and a C1-C6 monocarboxylic acid ammonium salt, The method according to claim 1 or 2, characterized in that the compound is selected from the group consisting of:

4. the C1 to C6 monocarboxylic acid is one or more selected from formic acid, acetic acid, and propionic acid; The method according to claim 3, wherein the mixture of a C1-C6 monocarboxylic acid and a C1-C6 monocarboxylic acid ammonium salt is selected from the group consisting of a mixture of formic acid and ammonium formate, a mixture of acetic acid and ammonium acetate, and a mixture of propionic acid and ammonium propionate.

5. the amount of the carboxylic acid group-containing substance used is 1 to 9% of the theoretical number of moles required for the complex formation reaction between the carboxylic acid group-containing substance and the rare earth element in the rare earth carbonate; 3. The method according to claim 1, wherein the concentration of the carboxylic acid group-containing substance in the aqueous solution of the carboxylic acid group-containing substance is 0.015 to 0.15 mol / L.

6. 3. The method according to claim 1, wherein the slurry is heated to 50 to 100° C. and reacted for 10 to 600 minutes.

7. A step of converting the intermediate product into basic rare earth carbonate crystals, basic rare earth carbonate clusters, or a mixture of basic rare earth carbonate crystals and basic rare earth carbonate clusters, followed by solid-liquid separation, and recycling the obtained filtrate as an aqueous solution of a carboxylic acid group-containing substance. The method of claim 1 or claim 2, further comprising:

8. Cl in rare earth carbonates - , S.O. 4 2- and NO 3 - The total content of the above exceeds 120 ppm, and the Cl content in basic rare earth carbonate is - , S.O. 4 2- and NO 3 - The total content of is 50 ppm or less than 50 ppm, Average particle diameter D of basic rare earth carbonate 50 3. The method according to claim 1, wherein the thickness is less than 5.5 μm.

9. 1. Use of a substance containing a carboxylic acid group, characterized in that it is used to increase the phase transition rate in the process of preparing a basic rare earth carbonate from a rare earth carbonate.

10. The carboxylic acid group-containing substance is (1) C1 to C6 monocarboxylic acid, or (2) A mixture of a C1-C6 monocarboxylic acid and a C1-C6 monocarboxylic acid ammonium salt, 10. The use according to claim 9, characterized in that it is selected from:

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