Preparation method of high-purity sphere-like nano yttrium oxide powder

Abstract

The invention belongs to the technical field of rare earth materials, and discloses a preparation method of high-purity sphere-like nano yttrium oxide powder. The method comprises the following preparation steps: (1) adding Y2O3 powder into concentrated hydrochloric acid, heating, stirring and dissolving, and then diluting with an ethanol water solution to obtain a YCl3 solution; (2) mixing ammonia water, a quaternary ammonium base aqueous solution and ethanol to prepare a precipitant solution, and dropwise adding the precipitant solution into the YCl3 solution in the step (1) for precipitation reaction to precipitate Y < 3 + >; and (3) separating and drying the precipitate obtained in the step (2), and then carrying out high-temperature calcination to obtain the high-purity spheroidal nano yttrium oxide powder. According to the preparation method, the ethanol water solution of YCl3 is used as a reaction solution, ammonia water is used as a main precipitator, quaternary ammonium base is used as an auxiliary precipitator and a surface active structure regulating agent, and yttrium oxide powder with the purity not lower than 5N and the particle size smaller than 100nm can be obtained.

Description

Technical Field

[0001] The present invention belongs to the technical field of rare earth materials, and particularly relates to a method for preparing high-purity spherical nano yttrium oxide powder. Background Art

[0002] Yttrium oxide is an important rare earth oxide, which has a broad optical transparency range, excellent light transmittance, high dielectric constant and chemical stability, and is widely used in the fields of optical materials, battery materials, magnetic materials and ceramic materials, etc.

[0003] The preparation method of yttrium oxide powder generally adopts the chemical precipitation method, which has the advantages of simple preparation method and low cost. However, in the process of producing yttrium oxide powder by the conventional chemical precipitation method, it is difficult to control the product purity and particle size, resulting in low product quality.

[0004] Chinese invention application with publication number CN 103539195 A discloses a method for preparing nano yttrium oxide powder, in which an inorganic acid salt solution containing yttrium is dropped into an alcohol-water mixed solution containing a precipitant and an electrostatic stabilizer. After the titration is completed, a surface modifier is added, and the reaction system is stirred, aged and separated. The precipitate is taken, and then it is purified, washed, vacuum dried and calcined to obtain nano yttrium oxide powder. Chinese invention application with publication number CN 110330048 A discloses that a yttrium salt aqueous solution and a precipitant aqueous solution mixed with a surfactant are mixed to carry out a precipitation reaction, and after obtaining the precipitate, it is subjected to staged calcination to obtain nano yttrium oxide powder. However, in the above preparation process of nano yttrium oxide powder, carbonates and acetates are generally used as precipitants, and it is difficult to control the product particle size, and the added surface modifiers such as silicate esters have an adverse effect on the product purity.

[0005] Chinese invention application with publication number CN 112209420 A discloses a method for preparing nano-scale yttrium oxide powder. First, micron-scale yttrium oxide powder is prepared by the precipitation method, and then nano-scale yttrium oxide powder is prepared by the hydrothermal method. In the process of preparing by the precipitation method, only micron-scale yttrium oxide raw particles can be obtained, and a binder and a dispersant need to be further added for sizing, ball milling and atomization drying granulation to obtain nano-scale yttrium oxide powder. However, the addition of the binder and the dispersant will also lead to a decrease in the purity of the yttrium oxide product.

[0006] Generally speaking, the types of precipitants and the addition of surfactants are crucial for the particle size of nano yttrium oxide powder. For example, Wu Hongda et al. (Synthesis and Characterization of Ultrafine Yttrium Oxide [J]. Inorganic Chemicals Industry, 2009, 41(3): 19-21) disclosed that in an aqueous solution of yttrium nitrate, using ammonia water, ammonium carbonate, and ammonium tartrate as precipitants to prepare a precursor, and calcining at 873K in air for 2h, nano-sized yttrium oxide powder with primary grains belonging to cubic crystals can be obtained. After refluxing the precursor with small molecule organic alcohols, the surface water of the precursor can be reduced, the dispersibility of the precursor can be improved, and it also helps to reduce the particle agglomeration degree during the calcination of the precursor. However, agglomerates are easily formed during the calcination process. Although the agglomeration can be prevented by refluxing treatment with organic alcohols, it is still difficult for the product particle size to reach below 100nm, and at the same time, the treatment process is increased. In addition, due to the addition of surfactants, there is adsorption of impurity ions and impurity residues after calcination, which has an adverse effect on the product purity. Summary of the Invention

[0007] Aiming at the above-mentioned shortcomings and deficiencies of the prior art, the purpose of the present invention is to provide a preparation method of high-purity spherical nano yttrium oxide powder. The preparation method of the present invention uses an ethanol aqueous solution of YCl 3 as a reaction solution, ammonia water as the main precipitant, and quaternary ammonium base as the auxiliary precipitant and surface active structure regulator, and spherical nano yttrium oxide powder with ultra-high purity (≥5N) and ultra-fine particle size (<100nm) can be obtained.

[0008] The purpose of the present invention is achieved through the following technical solutions: A preparation method of high-purity spherical nano yttrium oxide powder, comprising the following preparation steps: (1) Add Y 2 O 3 powder to concentrated hydrochloric acid, heat and stir to dissolve, and then dilute with an ethanol aqueous solution to obtain a YCl 3 solution; (2) Take ammonia water, quaternary ammonium base aqueous solution and ethanol to prepare a precipitant solution, and dropwise add the above precipitant solution to the YCl 3 solution in step (1) for a precipitation reaction to precipitate Y 3+ ; (3) Separate and dry the precipitate obtained in step (2), and then perform high-temperature calcination to obtain high-purity spherical nano yttrium oxide powder.

[0009] Furthermore, in step (1), the concentrated hydrochloric acid used is concentrated hydrochloric acid with a mass concentration of 36% - 38%; the temperature of the heating and stirring is 60 - 90°C, and the time is 15 - 60min.

[0010] Furthermore, in step (1), the YCl 3The volume percentage content of ethanol in the solution is 40% - 60%. In the case where the solvation of ethanol in the above proportion is combined with quaternary ammonium hydroxide as an auxiliary precipitant and a surface active structure regulator, the particle size of the obtained yttrium oxide powder can be significantly reduced and the particle size uniformity of the powder can be improved.

[0011] Further, the concentration of the YCl 3 solution in step (1) is 0.01 - 1 mol / L.

[0012] Further, the Y 2 O 3 powder in step (1) is a commercially available conventional Y 2 O 3 powder.

[0013] Further, the quaternary ammonium hydroxide in step (2) is at least one of tetramethylammonium hydroxide, trimethylethylammonium hydroxide, dimethyldiethylammonium hydroxide, methyltriethylammonium hydroxide, and tetraethylammonium hydroxide. More preferably, it is at least one of dimethyldiethylammonium hydroxide, methyltriethylammonium hydroxide, and tetraethylammonium hydroxide. The use of the above specific quaternary ammonium hydroxide has more suitable surface activity in the solvent system of the present invention, so the effect of reducing the particle size of the nano yttrium oxide powder is more significant.

[0014] Further, the addition amount of the precipitant solution in step (2) makes the pH value of the solution 7 - 9; the dropping time of the precipitant solution can be 0.5 - 1 h. After the precipitant solution is dropped, stirring reaction can be continued for 1 - 2 h.

[0015] Further, the molar ratio of the amount of the quaternary ammonium hydroxide to ammonia water (NH 3 ·H 2 O) is 0.05:1 - 0.5:1. If the amount of the quaternary ammonium hydroxide is too low, the effect of regulating the surface active structure cannot be achieved well, and if the amount of the quaternary ammonium hydroxide is too high, the cost will increase.

[0016] Further, the volume percentage content of ethanol in the precipitant solution is 40% - 60%.

[0017] Further, the high-temperature calcination in step (3) means calcining at a temperature of 600 - 900 °C for 1 - 5 h.

[0018] A high-purity spherical nano yttrium oxide powder is prepared by the above method; the purity of the high-purity spherical nano yttrium oxide powder is not less than 5N, and the average particle size is less than 100 nm.

[0019] Compared with the prior art, the beneficial effects of the present invention are: (1) The preparation method of the present invention uses YCl 3An ethanol aqueous solution is used as the reaction solution, and ammonia water and quaternary ammonium base are used as precipitants to precipitate Y ions. Under the regulation of the solvation of ethanol and the surface activity of the quaternary ammonium base, the particle size of the obtained precipitate and the particle size of the yttrium oxide powder after calcination can be significantly reduced, and the uniformity of the powder can be improved. (2) The present invention uses a specific quaternary ammonium base as a surface activity regulator. Compared with conventional surfactants with hydrophobic and / or hydrophilic long chains, it can reduce the adsorption or encapsulation of impurity ions by Y ions during the precipitation process, and the quaternary ammonium base or the salt formed by it is more easily decomposed by heating, which can significantly reduce the impurity residue after calcination and reduce the agglomeration of yttrium oxide powder during the roasting process, thereby significantly improving the purity of the final product and reducing the particle size of the product. The obtained nano yttrium oxide powder can meet the high purity requirement of 5N and the ultrafine particle size requirement of less than 100nm. Specific embodiments

[0020] The present invention will be further described in detail below with reference to the embodiments, but the embodiments of the present invention are not limited thereto. The dosage of each component is in parts by mass, parts by volume, g, mL. Example 1

[0021] A preparation method of high-purity spherical nano yttrium oxide powder includes the following preparation steps: (1) Add 56.5 parts by mass of crude Y 2 O 3 powder (commercially available, purity 4N) to 180 parts by volume of concentrated hydrochloric acid with a mass fraction of 36.5%, heat to 80 °C and stir for 30 min until completely dissolved, and then add 1820 parts by volume of 55 vt% ethanol aqueous solution for dilution to obtain a YCl 3 solution with a concentration of about 0.25 mol / L and an ethanol volume fraction of about 50%. 3 solution; (2) Take ammonia water, methyltriethylammonium hydroxide aqueous solution and ethanol and mix them to prepare a precipitant solution. The ammonia water concentration in the precipitant solution is 2 mol / L, the methyltriethylammonium hydroxide concentration is 0.4 mol / L, and the ethanol volume fraction is 50%. Add 800 parts by volume of the above precipitant solution dropwise to the YCl 3 solution in step (1). The dropping time of the precipitant solution is 45 min, measure the pH value of the solution to be 8.1, and then continue to stir and react for 1.5 h to fully form Y(OH) 3 precipitate; (3) Filter the precipitate obtained in step (2) by suction, place it in an oven at 80 °C and dry for 12 h to obtain a dry powder. Then place it in a muffle furnace and heat it to 800 °C at a heating rate of 10 °C / min and calcine for 2 h to obtain high-purity spherical nano yttrium oxide powder.

[0022] The nano yttrium oxide powder obtained in this example was tested for purity and found to be 5N; the metal impurity content was Fe 3 ppm and Na 5 ppm; the morphology was spherical. The D50 and D90 particle sizes of the dried powder before calcination and the nano yttrium oxide powder after calcination are shown in Table 1 below.

[0023] Table 1 Example 2

[0024] To further prove the effect of the quaternary ammonium base of the present invention as an auxiliary precipitant and a surface active structure regulator, different quaternary ammonium bases recorded in Table 2 were used to replace methyltriethylammonium hydroxide in Example 1, and the other conditions were the same; and a precipitant solution prepared with ammonia water alone (ammonia water concentration was 2.4 mol / L, without quaternary ammonium base) was used as a comparison. The purity of the obtained yttrium oxide powder and the particle size of the powder before and after calcination were tested respectively, and the results are shown in Table 2.

[0025] Table 2 Example 3

[0026] To further prove the influence of the solvation effect of ethanol of the present invention on the product performance, YCl solutions and precipitant solutions with different ethanol volume percentages recorded in Table 3 were used to replace the YCl solution and precipitant solution in Example 1 respectively, and the other conditions were the same; and water alone was used as the solvent system (ethanol was not added to both the YCl solution and the precipitant solution) for comparison. The purity of the obtained yttrium oxide powder and the particle size of the powder before and after calcination were tested respectively, and the results are shown in Table 3. 3 solution and precipitant solution 3 solution and precipitant solution 3 solution and precipitant solution

[0027] Table 3

[0028] It can be seen from the results in Table 3 that by adding ethanol to the precipitation solvent system of the present invention, the precipitation particle size can be significantly reduced. As the ethanol ratio increases, the obtained precipitation particle size shows a decreasing trend. However, when the ethanol volume ratio exceeds 60%, the precipitation particle size does not further decrease, and the uniformity of the particle size of the powder before and after calcination becomes worse. By controlling the ethanol volume ratio in the solvent system within the range of 40% - 60%, a product with uniform particle size and an average particle size < 100 nm can be obtained. Example 4

[0029] A preparation method of high-purity spherical nano yttrium oxide powder, comprising the following preparation steps: (1) 5.65 parts by mass of crude Y 2 O 3The powder (commercially available, purity 4N) was added to 18 volume parts of concentrated hydrochloric acid with a mass fraction of 36.5%, heated to 80 °C and stirred for 30 min until completely dissolved, and then diluted with 964 volume parts of 50 vt% ethanol aqueous solution to obtain YCl 3 solution with a concentration of about 0.05 mol / L and an ethanol volume fraction of about 48%; 3 (2) Ammonia water, methyltriethylammonium hydroxide aqueous solution and ethanol were mixed to prepare a precipitant solution. The concentration of ammonia water in the precipitant solution was 2 mol / L, the concentration of methyltriethylammonium hydroxide was 0.1 mol / L, and the ethanol volume fraction was 48%. 100 volume parts of the above precipitant solution were added dropwise to the YCl 3 solution in step (1). The dropping time of the precipitant solution was 30 min, the pH value of the solution was measured to be 8.9, and then stirring was continued for 2 h to fully form Y(OH) 3 precipitate; (3) The precipitate obtained in step (2) was filtered by suction, dried in an oven at 80 °C for 12 h to obtain a dry powder. Then it was placed in a muffle furnace and heated to 900 °C at a heating rate of 10 °C / min and calcined for 1 h to obtain high-purity spherical-like nano yttrium oxide powder.

[0030] The nano yttrium oxide powder obtained in this example was detected to be 5N in purity; the metal impurity content was 2 ppm for Fe and 4 ppm for Na; the morphology was spherical-like. The D50 and D90 particle sizes of the dry powder before calcination and the nano yttrium oxide powder after calcination are shown in Table 4 below.

[0031] Table 4 Example 5

[0032] A preparation method of high-purity spherical-like nano yttrium oxide powder, comprising the following preparation steps: (1) 113 mass parts of crude Y 2 O 3 The powder (commercially available, purity 4N) was added to 350 volume parts of concentrated hydrochloric acid with a mass fraction of 36.5%, heated to 80 °C and stirred for 30 min until completely dissolved, and then diluted with 650 volume parts of 70 vt% ethanol aqueous solution to obtain YCl 3 solution with a concentration of about 1 mol / L and an ethanol volume fraction of about 45%; 3 (2) Ammonia water, methyltriethylammonium hydroxide aqueous solution and ethanol were mixed to prepare a precipitant solution. The concentration of ammonia water in the precipitant solution was 2 mol / L, the concentration of methyltriethylammonium hydroxide was 1 mol / L, and the ethanol volume fraction was 45%. 100 volume parts of the precipitant solution were added dropwise to the YCl 3 ​​Add 1200 volume parts of the above precipitating agent solution dropwise to the solution. The dropping time of the precipitating agent solution is 60 min. Measure the pH value of the solution to be 8.5, and then continue stirring and reacting for 1 h to allow Y(OH) 3 precipitate to fully form; (3) Filter the precipitate obtained in step (2) by suction, place it in an oven and dry it at 80 °C for 12 h to obtain a dry powder. Then place it in a muffle furnace and heat it at a heating rate of 10 °C / min to 600 °C and calcine it for 5 h to obtain high-purity spherical nano-yttrium oxide powder.

[0033] The nano-yttrium oxide powder obtained in this example was detected to be 5N in purity; the metal impurity content was 3 ppm for Fe and 6 ppm for Na; the morphology was spherical. The D50 and D90 particle sizes of the dry powder before calcination and the nano-yttrium oxide powder after calcination are shown in Table 5 below.

[0034] Table 5 Comparative example

[0035] To further prove the influence of using quaternary ammonium base as the surface active structure regulator on the product purity in the present invention compared with other surfactants, the following comparative examples of conventional surfactants were set up: (1) Add 56.5 parts by mass of coarse Y 2 O 3 powder (commercially available, purity 4N) to 180 volume parts of concentrated hydrochloric acid with a mass fraction of 36.5%, heat to 80 °C and stir for 30 min until completely dissolved, and then add 1820 volume parts of 55 vt% ethanol aqueous solution for dilution to obtain YCl 3 solution with a concentration of about 0.25 mol / L and an ethanol volume fraction of about 50% of YCl 3 solution; (2) Add 0.4 wt% of the surfactants as described in Table 6 to the YCl 3 solution in step (1) and mix evenly, then add 800 volume parts of precipitating agent solution (50 vt% ethanol aqueous solution with an ammonia concentration of 2.4 mol / L) dropwise. The dropping time of the precipitating agent solution is 45 min. Measure the pH value of the solution to be 8.1, and then continue stirring and reacting for 1.5 h to allow Y(OH) 3 precipitate to fully form; (3) Filter the precipitate obtained in step (2) by suction, place it in an oven and dry it at 80 °C for 12 h to obtain a dry powder. Then place it in a muffle furnace and heat it at a heating rate of 10 °C / min to 800 °C and calcine it for 2 h to obtain nano-yttrium oxide powder.

[0036] The particle size and purity results of the products obtained in this comparative example under different surfactant conditions are shown in Table 6 below.

[0037] Table 6

[0038] As can be seen from the above comparison results, the purity of the product obtained by using conventional surfactants cannot reach 5N, and the particle size increases significantly. In the present invention, a specific quaternary ammonium base is used as a surface activity regulator. Compared with conventional surfactants, it can significantly improve the purity of the finally obtained product, reduce the content of metal impurities and reduce the particle size of the product. The obtained nano-yttrium oxide powder can meet the ultra-high purity requirement of 5N and the ultra-fine particle size requirement of less than 100 nm. The reason is that the present invention uses a specific quaternary ammonium base as a surface activity regulator. Compared with conventional surfactants having hydrophobic and / or hydrophilic long chains, it can reduce the adsorption or encapsulation of impurity ions by Y ions during the precipitation process, and the quaternary ammonium base or the salt formed by it is more easily decomposed by heating, which can significantly reduce the impurity residue after calcination and reduce the agglomeration of yttrium oxide powder during the roasting process, thereby significantly improving the purity of the finally obtained product and reducing the particle size of the product.

[0039] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited by the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications made without departing from the spirit and principle of the present invention shall be equivalent replacement methods and are all included in the protection scope of the present invention.

Claims

1. A method for preparing high-purity spherical nano-yttrium oxide powder, characterized in that: The method comprises the following preparation steps: (1) Add Y2O3 powder to concentrated hydrochloric acid, heat and stir to dissolve, and then dilute with ethanol aqueous solution to obtain YCl3 solution; (2) Ammonia water, quaternary ammonium alkali aqueous solution and ethanol are mixed to prepare a precipitant solution, and the precipitant solution is added dropwise to the YCl3 solution in step (1) to perform a precipitation reaction to make Y 3+ precipitation; (3) The precipitate obtained in step (2) is separated, dried, and then calcined at high temperature to obtain high-purity spherical nano-yttrium oxide powder.

2. The preparation method according to claim 1, characterized in that: The concentrated hydrochloric acid in step (1) has a mass concentration of 36% to 38%; the heating and stirring is performed at a temperature of 60 to 90° C. for 15 to 60 minutes.

3. The preparation method according to claim 1, characterized in that: The volume percentage of ethanol in the YCl3 solution in step (1) is 40% to 60%; the volume percentage of ethanol in the precipitant solution in step (2) is 40% to 60%.

4. The preparation method according to claim 1, characterized in that: The concentration of the YCl3 solution in step (1) is 0.01~1 mol / L.

5. The preparation method according to claim 1, characterized in that: The quaternary ammonium base in step (2) is at least one of tetramethylammonium hydroxide, trimethylethylammonium hydroxide, dimethyldiethylammonium hydroxide, methyltriethylammonium hydroxide and tetraethylammonium hydroxide.

6. The preparation method according to claim 1, characterized in that: The quaternary ammonium base in step (2) is at least one of dimethyldiethylammonium hydroxide, methyltriethylammonium hydroxide and tetraethylammonium hydroxide.

7. The preparation method according to claim 1, characterized in that: The amount of the precipitant solution added in step (2) is such that the pH value of the solution is 7-9.

8. The preparation method according to claim 1, characterized in that: The molar ratio of the quaternary ammonium base to the ammonia water is 0.05:1 to 0.5:

1.

9. The preparation method according to claim 1, characterized in that: The high temperature calcination in step (3) refers to calcination at a temperature of 600-900° C. for 1-5 hours.

10. A high-purity spherical nano-yttrium oxide powder, characterized in that: The high-purity spherical nano-yttrium oxide powder is prepared by the method described in any one of claims 1 to 9; the purity of the high-purity spherical nano-yttrium oxide powder is not less than 5N, and the average particle size is less than 100nm.

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