Preparation method of needle-shaped cerous carbonate

Abstract

The invention discloses a preparation method of needle-shaped cerium carbonate, and belongs to the technical field of rare earth compound preparation. And adding the rare earth cerium salt solution and the ammonium bicarbonate solution into the base solution for reaction to obtain the needle-shaped cerium carbonate. According to the preparation method of the needle-shaped cerous carbonate, the concentration of the rare earth salt solution is controlled, and the proper supersaturation degree of the system can be maintained, so that the change of the crystal growth rate is controlled, and the controllable synthesis of the crystal morphology is realized. In the process that rare earth salt and ammonium bicarbonate react to generate precipitates, acetic acid wraps the surfaces of crystallized crystals and further covers growth active center points on the surfaces of the crystals, so that the product shows oriented growth characteristics, and the crystals grow mainly in one-dimensional growth and develop towards needle-shaped crystals. The preparation method is simple, low in raw material price, short in production period and suitable for industrial production.

Description

Technical Field

[0001] The invention relates to the technical field of rare earth compound preparation, in particular to a method for preparing needle-shaped cerium carbonate. Background Art

[0002] Due to its unique 4f layer electronic structure, cerium oxide has excellent optical, electrical and magnetic properties and is widely used in catalysis, energy and other fields. Cerium oxides of different morphologies can lead to different performances of the material, and cerium oxide is usually made by calcining cerium carbonate. Cerium oxide and cerium carbonate have inherited morphologies, so controlling the morphology of cerium carbonate particles can control the morphology of cerium dioxide particles. Therefore, the crystallization process and morphology control of cerium carbonate crystals are of great significance for the preparation of cerium dioxide with different morphologies.

[0003] Normally, the preparation of cerium carbonate in industry adopts liquid phase precipitation method, which has mild reaction conditions and low cost. With the development of science and technology, the demand for cerium oxide with special morphology is getting higher and higher, and different morphologies determine different application fields. Therefore, exploring simple and controllable preparation technology has become a new research direction. Since the morphology of cerium oxide is hereditary during roasting, the controllable synthesis of the special morphology of cerium carbonate can obtain cerium oxide with special morphology.

[0004] CN107098374A discloses a uniformly dispersed block-shaped cerium carbonate crystal and a preparation method thereof. In a simulated biomineralization environment system, disodium ethylenediaminetetraacetic acid is used as a soft template agent, a soluble cerium salt is used as a raw material, and a soluble carbonate is used as a precipitant to prepare uniformly dispersed block-shaped cerium carbonate crystals. However, the concentration of the cerium salt and the precipitant used in this method is low, the subsequent wastewater treatment volume is large, and aging treatment is required after the reaction is complete, which increases the production cycle and has a high cost.

[0005] CN110255598A discloses a method for preparing flower-shaped microsphere cerium carbonate and cerium dioxide, wherein 0.02-2.0 mol / L of precipitant solution is added to 0.02-1.0 mol / L of cerium salt solution, and the reaction is carried out at a reaction temperature below 20°C. The reaction product is filtered, washed and dried to obtain a flower-shaped microsphere cerium carbonate precursor, and then calcined at 500-700°C to obtain flower-shaped microsphere cerium dioxide. However, this method needs to react at a temperature below 20°C, and an additional cooling method is required; at the same time, the solubility of the precipitant solution and the cerium salt solution is low, and the subsequent processing cost increases.

[0006] CN114604888A discloses a method for preparing rod-shaped, cubic and polyhedral cerium oxide, wherein a soluble precursor salt solution of cerium is mixed with a precipitant solution, the obtained precipitate is filtered and washed, and then redispersed in one or more of diol or polyol solutions with a carbon number ≥ 3, and then after crystallization treatment, the sample mixture is filtered, washed and dried to obtain one or more of rod-shaped, cubic and polyhedral cerium oxide. However, this method obtains the desired morphology rare earth compound through the preparation of carbonate and subsequent crystallization treatment, which prolongs the process flow; at the same time, the crystallization temperature is high, the crystallization time is long, and the production cost is greatly increased. Summary of the invention

[0007] The purpose of the present invention is to provide a method for preparing needle-shaped cerium carbonate to solve the problems existing in the above-mentioned prior art.

[0008] To achieve the above object, the present invention provides the following solutions:

[0009] One of the technical solutions of the present invention is a method for preparing needle-shaped cerium carbonate, comprising the following steps: adding a rare earth cerium salt solution and an ammonium bicarbonate solution into a base liquid for reaction to obtain needle-shaped cerium carbonate;

[0010] The base liquid contains at least one of monocarboxylic acid or monocarboxylate salt.

[0011] The second technical solution of the present invention is the needle-shaped cerium carbonate prepared by the preparation method.

[0012] Based on the above technical solution, the present invention has the following technical effects:

[0013] The present invention provides a method for preparing needle-shaped cerium carbonate. By controlling the concentration of a rare earth salt solution, a suitable supersaturation of the system can be maintained, thereby controlling the change in the crystal growth rate and realizing controllable synthesis of the crystal morphology. In the process of generating a precipitate by the reaction of a rare earth salt with ammonium carbonate, acetic acid is wrapped around the surface of the crystal, thereby covering the growth active center points on the surface of the crystal, so that the product exhibits an oriented growth characteristic, causing the growth of the crystal to become mainly one-dimensional growth, and develop towards needle-shaped crystals. By controlling various parameters in the reaction process, the crystal exhibits an oriented growth characteristic, so that the selectivity of the morphological growth is affected, so that the crystal grows mainly in one dimension, and develops towards needle-shaped crystals. The preparation method of the present invention is simple, the raw material price is low, the production cycle is short, and it is suitable for industrial production. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0015] Figure 1 This is a SEM image of the cerium carbonate obtained in Example 1 of the present invention. DETAILED DESCRIPTION

[0016] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as limiting the present invention, but should be understood as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0017] It should be understood that the terms described in the present invention are only for describing special embodiments and are not intended to limit the present invention. In addition, for the numerical range in the present invention, it should be understood that each intermediate value between the upper and lower limits of the scope is also specifically disclosed. Each smaller range between the intermediate value in any stated value or stated range and any other stated value or intermediate value in the described range is also included in the present invention. The upper and lower limits of these smaller ranges can be independently included or excluded in the scope.

[0018] Unless otherwise indicated, all technical and scientific terms used herein have the same meanings as those generally understood by those skilled in the art. Although the present invention describes only preferred methods and materials, any methods and materials similar or equivalent to those described herein may also be used in the implementation or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials associated with the documents. In the event of a conflict with any incorporated document, the content of this specification shall prevail.

[0019] It will be apparent to those skilled in the art that various modifications and variations may be made to the specific embodiments of the present invention description without departing from the scope or spirit of the present invention. Other embodiments derived from the present invention description will be apparent to those skilled in the art. The present application description and examples are exemplary only.

[0020] The words “include,” “including,” “have,” “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.

[0021] The technical solutions described in the present invention, unless otherwise specified, are all conventional solutions in the art, and the reagents or raw materials used, unless otherwise specified, are purchased from commercial channels or have been disclosed.

[0022] The embodiment of the present invention provides a method for preparing needle-shaped cerium carbonate, comprising the following steps: adding a rare earth cerium salt solution and an ammonium bicarbonate solution into a base liquid for reaction to obtain needle-shaped cerium carbonate;

[0023] The base liquid contains at least one of monocarboxylic acid or monocarboxylate salt.

[0024] In some specific embodiments, the rare earth cerium salt is selected from at least one of cerium chloride, cerium nitrate or cerium sulfate.

[0025] In some specific embodiments, the concentration of the rare earth cerium salt solution is 200-330 g / L, preferably 250-300 g / L.

[0026] In the present invention, the mass of the rare earth soluble salt is measured as REO, where REO represents rare earth oxide. Controlling the concentration of the rare earth salt solution can maintain a suitable supersaturation of the system, thereby controlling the change in crystal growth rate and achieving controllable synthesis of crystal morphology.

[0027] In some specific embodiments, the concentration of the ammonium bicarbonate solution is 1.0 to 3.3 mol / L, preferably 2.5 to 3.0 mol / L.

[0028] In some specific embodiments, the rare earth cerium and Ce in ammonium bicarbonate 3+ With CO3 2- The molar ratio is 1:(2.5 to 3.8), preferably 1:(2.6 to 3.4), and more preferably 1:(3.0 to 3.2).

[0029] In some specific embodiments, the monocarboxylic acid is acetic acid; the monocarboxylate is an alkali metal acetate or ammonium acetate; the mass ratio of the monocarboxylic acid or the monocarboxylate to the rare earth cerium salt is (1-10):100, preferably (1-6):100, and more preferably (2-5):100.

[0030] During the reaction of rare earth salts and ammonium carbonate to form precipitation, acetic acid is wrapped around the surface of the crystals, thereby covering the growth active center points on the surface of the crystals, showing an oriented growth characteristic, causing the growth of the crystals to become mainly one-dimensional growth and develop towards needle-shaped crystals.

[0031] In some specific embodiments, the reaction temperature is 20-80°C, preferably 35-45°C.

[0032] The present invention controls various parameters in the reaction process so that the crystal exhibits oriented growth characteristics, affects the selectivity of morphological growth, and thus the crystal mainly grows in one dimension and develops toward needle-shaped crystals.

[0033] In some specific embodiments, after solid-liquid separation, the solid product is washed with deionized water in an amount 3 to 6 times the mass of the solid.

[0034] The embodiment of the present invention also provides needle-shaped cerium carbonate prepared by the preparation method.

[0035] Example 1

[0036] At 25°C, 140 mL of 280 g / L cerium chloride solution and 300 mL of 2.5 mol / L ammonium bicarbonate solution were added dropwise in parallel to a reactor containing 200 mL of pure water with 2 g of acetic acid as the base liquid, and mixed and reacted at 25°C. The reaction end point pH was 6.7.

[0037] The precipitated product was vacuum filtered and rinsed with 6 times the mass of deionized water. The morphology of the obtained cerium carbonate was needle-shaped. The SEM image was tested using a ZEISS Sigma 500 scanning electron microscope. Figure 1 shown.

[0038] Example 2

[0039] At 35°C, 140 mL of 280 g / L cerium chloride solution and 300 mL of 2.5 mol / L ammonium bicarbonate solution were added dropwise in parallel to a reactor containing 200 mL of pure water with 0.8 g of acetic acid as the base liquid, and mixed and reacted at 35°C. The reaction end point pH was 6.7.

[0040] The precipitated product was vacuum filtered and rinsed with 6 times the mass of deionized water, and the obtained cerium carbonate had a needle-like morphology.

[0041] Example 3

[0042] At 45°C, 130 mL of 300 g / L cerium chloride solution and 250 mL of 3.0 mol / L ammonium bicarbonate solution were added dropwise in parallel to a reactor containing 200 mL of pure water added with 2 g of acetic acid as a base liquid, and mixed and reacted at 45°C. The reaction end point pH was 6.7.

[0043] The precipitated product was vacuum filtered and rinsed with 6 times the mass of deionized water, and the obtained cerium carbonate had a needle-like morphology.

[0044] Example 4

[0045] At 45°C, 130 mL of 300 g / L cerium chloride solution and 300 mL of 2.5 mol / L ammonium bicarbonate solution were added dropwise in parallel to a reactor containing 200 mL of pure water with 0.8 g of acetic acid as the base liquid, and mixed and reacted at 45°C. The reaction end point pH was 6.7.

[0046] The precipitated product was vacuum filtered and rinsed with 6 times the mass of deionized water, and the obtained cerium carbonate had a needle-like morphology.

[0047] Example 5

[0048] At 65°C, 130 mL of 300 g / L cerium chloride solution and 266 mL of 2.8 mol / L ammonium bicarbonate solution were added dropwise in parallel to a reactor containing 200 mL of pure water as a base liquid and 2.0 g of acetic acid, and mixed and reacted at 65°C. The reaction end point pH was 6.7.

[0049] The precipitated product was vacuum filtered and rinsed with 6 times the mass of deionized water, and the obtained cerium carbonate had a needle-like morphology.

[0050] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation methods of the present invention. For ordinary technical users in the relevant field, other different forms of changes or modifications can be made on the basis of the above description. It is not necessary and impossible to list all the implementation methods here. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A method for preparing needle-shaped cerium carbonate, characterized in that: The method comprises the following steps: adding a rare earth cerium salt solution and an ammonium bicarbonate solution into a base liquid for reaction to obtain needle-shaped cerium carbonate; The base liquid contains at least one of monocarboxylic acid or monocarboxylate salt.

2. The preparation method according to claim 1, characterized in that: The rare earth cerium salt is selected from at least one of cerium chloride, cerium nitrate or cerium sulfate.

3. The preparation method according to claim 1, characterized in that: The concentration of the rare earth cerium salt solution is 200-330 g / L.

4. The preparation method according to claim 1, characterized in that: The concentration of the ammonium bicarbonate solution is 1.0-3.3 mol / L, and the rare earth cerium salt and Ce in the ammonium bicarbonate are 3+ With CO3 2- The molar ratio is 1:(2.5~3.8).

5. The preparation method according to claim 1, characterized in that: The monocarboxylic acid is acetic acid; the monocarboxylate is alkali metal acetate or ammonium acetate; the mass ratio of the monocarboxylic acid or the monocarboxylate to the rare earth cerium salt is (1-10):

100.

6. The preparation method according to claim 1, characterized in that: The reaction temperature is 20-80°C.

7. The needle-shaped cerium carbonate prepared by the preparation method according to any one of claims 1 to 6.

Images