KR20130058523A - A preparation method of zinc oxide by wet precipitation - Google Patents

Abstract

PURPOSE: A manufacturing method of zinc oxide powder is provided to manufacture the zinc oxide powder having uniform particle size distribution and fine particle size of 50 nm by optimally controlling the pH range of a neutralizing process, neutralizing agent injection speed, aging temperature, and aging time through a wet deposition method. CONSTITUTION: A manufacturing method of zinc oxide powder comprises the following steps: zinc ingot is dissolved in nitric acid solution; ammonia solution is injected to the solution of the previous step and neutralized to obtain zinc oxide solid product; the zinc oxide solid product is dehydrated; the dehydrated zinc oxide solid product is dried; the dried zinc oxide solid product is calcined; and the calcined zinc oxide solid product is pulverized to obtain zinc oxide powder. In the zinc ingot dissolving step, the mole ratio of zinc and nitric acid is 1:4-1:6. In neutralization of the ammonia solution injection step, pH is 5-6. In neutralization of the ammonia solution injection step, the injection speed of ammonia solution is 2.5-10.0 wt%/min. In neutralization of the ammonia solution injection step, the aging temperature is 10-50 deg. C and the aging time is 4-12 hours. [Reference numerals] (a) Dissolution/neutralization; (b) Dehydration; (c) Drying; (d) Calcination; (e) Crushing

Description

A preparation method of zinc oxide by wet precipitation

The present invention relates to a method for producing zinc oxide powder by a wet precipitation method, and more particularly, by using a wet precipitation method in which a zinc ingot is directly dissolved in a nitric acid solution and ammonia water as a neutralizer is added thereto, The present invention relates to a method for preparing zinc oxide powder having a uniform particle size distribution and a fine particle size of about 50 nm by optimally controlling the rate of neutralizing agent, aging temperature, and aging time.

White powder zinc oxide has various functions such as semiconductivity, photoconductivity, piezoelectric fluorescent, and has been widely used in various industrial fields such as semiconductors, solar cells, displays, cosmetics, paints, and catalysts. When zinc oxide is manufactured in nano size, the utilization value is further increased because it has different physicochemical properties from bulk materials such as high activity of powder and low sintering temperature due to increase of specific surface area at the interface.

Recently, in the development of high-tech materials, the demand for high-performance inorganic materials including zinc oxide is increasing, narrowing the particle size distribution and increasing interest in high-purity spherical fine particles (T. Sugimoto,Advances in Colloid and Interface Science, 1987, 28, 65).

In general, chemical methods for preparing zinc oxide fine powder can be classified into gas phase method and liquid phase method, and gas phase method can be classified into indirect method and direct method, and the method should be changed according to the starting material and the type of zinc compound to be obtained. (O. Sakurai et al., Journal of Materials Science , 1986, 21, 3698).

As a method for producing zinc oxide fine particle powder using a gas phase reaction, a vapor phase oxidation method of zinc vapor and a vapor phase reaction method of a water vapor and an acetylacetonate complex are known. In addition, Liu et al. Prepared spherical droplets of zinc solution and decomposed the droplets with spray heat for the purpose of producing monodisperse zinc oxide (TQ Liu et al., Journal of Materials Science , 1986, 21, 98), this method is easily formed into zinc oxide aggregates due to the strong cohesion between the produced particles, it is known that expensive manufacturing costs are incurred (DW Sproson et al., Ceramic International , 1986, 12, 3).

In addition, a method of preparing a zinc oxide having a uniform size by a two-step solution precipitation method using zinc hydroxide salt as a precursor in the method of preparing zinc oxide by using a liquid phase reaction has been reported. SM Haile et al., Journal of the American Ceramic Society , 1989, 72 (10), 2004). The Tsuchida group hydrolyzed zinc sulfate and zinc nitrate solutions in the presence of urea to obtain zinc oxide in the form of hexagonal prismatic and spindle forms of monodispersion (T. Tsuchida et al., Chemistry Letters , 1990, 19, 1769).

The above-mentioned conventional methods for producing zinc oxide fine particles by gas phase and liquid phase methods have disadvantages, respectively. The production by gas phase method is difficult to control the shape and size of the resulting zinc oxide fine particles to present various kinds of products. It is difficult, and manufacturing equipment cost is high, and manufacturing cost increases. In addition, since the liquid phase method uses expensive precursors such as acetate and chloride, the production cost increases due to the increase in the cost of the precursor and includes impurities other than zinc oxide after the synthesis reaction. Difficulties follow

In view of the above, the inventors of the present invention studied the pH of the zinc ingot solution in the neutralization step of the study, controlling the input rate of the ammonia water used as the neutralizing agent, the ripening time, the wet temperature by using the zinc ingot directly. By manufacturing zinc oxide powder by precipitation method, it is possible to lower manufacturing cost by not using expensive equipment and zinc precursor compared to conventional gas phase and liquid phase method. Spherical zinc oxide powder with narrow purity particle size distribution through high optimization of production process The present invention was completed by confirming that can be obtained.

It is an object of the present invention to provide a method for producing zinc oxide powder using a wet precipitation method in which a zinc ingot is directly dissolved in a nitric acid solution and ammonia water as a neutralizer is added thereto.

In order to solve the above problems, the present invention provides a method for producing zinc oxide powder comprising the following steps.

1) dissolving zinc ingot in aqueous nitric acid solution (step 1);

2) obtaining a zinc oxide solid product by adding ammonia water to the solution of step 1) and neutralizing it (step 2);

3) dehydrating the zinc oxide solid product (step 3);

4) drying the dehydrated zinc oxide solid product (step 4);

5) calcining the dried zinc oxide solid product (step 5); And

6) disintegrating the calcined zinc oxide solid product to obtain zinc oxide powder (step 6).

Preferably, the step 3) may further comprise the step of washing the zinc oxide solid product with ultrapure water (step 3-1).

Step 1 is a step of dissolving the zinc ingot in an aqueous solution of nitric acid, and dissolving the zinc ingot in an aqueous solution of nitric acid to form zinc hydroxide as a zinc precursor.

As used herein, the term "zinc ingot" refers to a mass of castings formed into a predetermined shape by injecting molten zinc into a mold or a sand mold.

The present invention is characterized in that the zinc oxide powder is directly prepared using a zinc ingot rather than a zinc compound.

In the present invention, 20 to 80% of nitric acid aqueous solution may be preferably used. Specifically, in an embodiment of the present invention, 30% nitric acid solution was used.

In step 1) of the present invention, the molar ratio of zinc and nitric acid is preferably 1: 4 to 1: 6. If the molar ratio of zinc and nitric acid is less than the lower limit, the zinc ingot is difficult to be completely dissolved in nitric acid, and thus zinc oxide does not facilitate nucleation and particle growth, resulting in a poor production yield of zinc oxide powder. This is because the production yield of zinc oxide powder does not increase significantly even larger.

Step 2 is a step of obtaining a zinc oxide solid product by adding ammonia water to the solution of step 1) to neutralize, to obtain a zinc oxide solid product from zinc hydroxide by adding ammonia water as a neutralizing agent.

In the present invention, preferably 10 to 50% of ammonia water can be used. Specifically, in one embodiment of the present invention used 28% ammonia water.

When neutralizing the step 2), the pH is preferably 5 to 6. If the pH is outside this range, no zinc oxide solid product is produced.

In the neutralization of step 2), the input rate of the ammonia water is preferably 2.5 to 10.0 wt% / min. If the feed rate of the ammonia water is slower than the lower limit, the production rate of the zinc oxide solid product is slow and the particle size of the zinc oxide powder finally produced is large, and if it is faster than the upper limit, the particle size of the zinc oxide powder finally produced is uneven. There is this.

In the neutralization of step 2), the aging temperature is preferably 10 to 50 ° C. If the aging temperature is lower than the lower limit, there is a disadvantage in that the particle size of the finally produced zinc oxide powder is non-uniform, and if it is higher than the upper limit, there is a disadvantage in that no zinc oxide powder is produced.

In the neutralization of step 2), the aging time is preferably 4 to 12 hours. If the aging time is outside the above range, there is a disadvantage in that the particle size of the finally produced zinc oxide powder is large and uneven.

In step 3, the zinc oxide solid product is dehydrated, and the zinc oxide solid product is dehydrated to remove the nitric acid solution and the ammonia water.

Dehydration of step 3) may be performed using a centrifugal dehydrator, but is not limited thereto.

In step 3-1, the zinc oxide solid product is washed with ultrapure water, and the zinc oxide solid product is washed with ultrapure water to remove residual nitric acid solution and ammonia water.

In step 4, the dehydrated zinc oxide solid product is dried, and the dehydrated zinc oxide solid product is dried to evaporate all moisture.

The drying of step 4) may be performed at 80 to 120 ° C. for 8 to 24 hours, and particularly preferably at 100 ° C. for 12 hours. The drying may be carried out in an oven, but is not limited thereto.

Step 5 is a step of calcining the dried zinc oxide solid product, wherein the dried zinc oxide solid product is calcined to remove impurities remaining during the reaction.

The calcination of step 5) may be performed at 250 to 400 ° C. for 2 to 6 hours, and particularly preferably at 300 ° C. for 4 hours. The calcination can be performed in an electric furnace, but is not limited thereto.

In step 6, the calcined zinc oxide solid product is pulverized to obtain zinc oxide powder, and the calcined zinc oxide solid product is crushed so that the aggregated portions can be separated from each other to obtain zinc oxide powder. .

Disintegration of step 6) may be performed by injecting air at an air pressure of 4 to 8 kg, particularly preferably by injecting air at an air pressure of 6 kg.

Hereinafter, the configuration of the present invention will be described in detail with reference to the drawings.

1 is a step of obtaining a zinc oxide solid product by dissolving zinc ingot in an aqueous solution of nitric acid (step 1) and neutralizing by adding ammonia water to the solution of step 1 in the manufacturing step of the zinc oxide powder of the present invention (step 2) It is a schematic diagram showing the structure of the manufacturing apparatus for performing the).

Figure 2 shows each preparation step of the inventive zinc oxide powder comprising dissolution / neutralization step, dehydration step, drying step, calcination step, pulverization step and the equipment used in each of the above steps.

In one embodiment of the present invention, a zinc ingot (purity 99.99%), 30% nitric acid solution (HNO ₃ ), and 28% aqueous ammonia (NH ₄ OH) are used as materials.

Specifically, a batch reactor for the production of zinc oxide may be used 200 L class, and the zinc ingot is added to the reactor (1) containing the nitric acid solution to dissolve. In the next step, ammonia water in the precipitant reservoir 2 is introduced at a constant rate through the flow rate controller 3 to neutralize the nitric acid solution to precipitate and produce a zinc oxide cake.

At this time, the zinc oxide powder may be prepared by varying the neutralization conditions by the pH value, the neutralizing agent (ammonia) input rate, the aging temperature, the aging time in the neutralization step.

Specifically, the molar ratio of nitric acid to dissolve the zinc ingot is carried out in the range of 1: 4 to 1: 6 of zinc and nitric acid. The nitric acid solution in which the zinc ingot is melted is introduced into the reactor at a feed rate of 2.5 to 10.0 wt% per minute while ammonia water, which is a neutralizing agent, is sufficiently stirred at 150 to 300 rpm through the stirrer 4. The pH of the solution is adjusted to 5-6, and the pH change of the reaction solution is precisely measured by a pH meter during the synthesis reaction. In addition, the aging temperature is controlled in the range of 10 ~ 50 ℃ through the temperature controller 5, the aging time is changed to 4 to 12 hours.

In the dissolving and neutralizing step, the zinc oxide synthesis mechanism is a zinc ingot dissolved in nitric acid solution to form a zinc precursor Zn (OH) ₂ as shown in the following scheme (step 1), Zn (OH) by the addition of a neutralizing agent _It proceeds to step (step 2) to form bivalent ZnO.

1st stage) Zn ^{2 +} + 2HNO ₃ → Zn (OH) ₂ + 2NO ₂

Step 2) Zn (OH) ₂ + 2NH ₄ OH → ZnO + H ₂ O + 2NH ₄ OH

The zinc oxide solid product in the form of a cake obtained in the dissolving and neutralizing step is removed by using a centrifugal dehydrator in a dehydration step (step 3). The dehydrated zinc oxide cake is washed with ultrapure water (DI water) 10 to 20 times to remove all remaining nitric acid solution and ammonia water (step 3-1). After drying in the drying step at 80 to 120 ℃ for 8 to 24 hours to evaporate all the water, such as ultrapure water used during the washing process (step 4). The dried and physically aggregated large agglomerates are pulverized with a pestle and passed through a 150 to 300 mesh, followed by a calcination step at 250 to 400 ° C. for 2 to 6 hours in an electric furnace to further remove all remaining impurities during the reaction ( Step 5). Finally, the finely aggregated zinc oxide powder obtained in the previous step is pulverized so that the aggregated portion of the wet precipitation can be separated from each other through the high pressure air injection of 4 to 8 kg air pressure (step 6).

As described above, in the present invention, zinc oxide fine particles, that is, zinc oxide powder may be manufactured by using a wet precipitation method in which a zinc ingot is directly dissolved in a nitric acid solution and ammonia water as a neutralizer is added thereto.

At this time, the zinc oxide fine particles were finally prepared by varying the neutralization conditions by the pH range, the neutralizer input rate, the aging temperature, and the aging time in the neutralization process, and the characteristics of the particle size and shape thereof were investigated. The pH range of, the rate of neutralizer loading, the temperature of aging, and the time of aging were found to be important factors influencing the particle size and shape of the zinc oxide powder.

In particular, in the present invention, by using the cheap zinc ingot directly by the wet precipitation method by optimally controlling the pH range of the neutralization process, the neutralizing agent input rate, the aging temperature, the aging time as described above, the uniform particle size distribution and the fineness of about 50 nm Zinc oxide powder having a particle size can be obtained.

In addition, the production yield of the zinc oxide powder produced by the wet precipitation method was confirmed that the molar ratio of zinc and nitric acid used is 1 to 6 (92.6%) maximum.

The present invention can provide a method for producing zinc oxide powder by using a wet precipitation method in which the zinc ingot is directly dissolved in nitric acid solution and ammonia water as a neutralizing agent is added thereto. By controlling the aging time optimally, zinc oxide powder having a uniform particle size distribution and a fine particle size of about 50 nm can be obtained by directly using a cheap zinc ingot by wet precipitation method.

1 is a step of obtaining a zinc oxide solid product by dissolving zinc ingot in an aqueous solution of nitric acid (step 1) and neutralizing by adding ammonia water to the solution of step 1 in the manufacturing step of the zinc oxide powder of the present invention (step 2) It is a schematic diagram showing the structure of the manufacturing apparatus for performing the).
Figure 2 shows each preparation step of the inventive zinc oxide powder comprising dissolution / neutralization step, dehydration step, drying step, calcination step, pulverization step and the equipment used in each of the above steps.
Figure 3 shows the appearance (a), SEM picture (scale bar: 100 nm) (b), XRD measurement results (c), and TEM picture (scale bar: 50 nm) of the 50 nm class milky white zinc oxide powder obtained in the present invention. (d).
Figure 4 shows the SEM photographs and particle size analysis results showing the particle shape of the zinc oxide powder obtained according to the pH change. In this case, (a) is pH: 5.0, (b) is pH: 5.5, (c) is pH: 6.0.
Figure 5 shows the SEM photographs and particle size analysis results showing the particle shape of the zinc oxide powder obtained according to the neutralizer loading rate. In this case, (a) is 2.5 wt% / min, (b) is 5.0 wt% / min, and (c) is 10 wt% / min.
Figure 6 shows the SEM photographs and particle size analysis results showing the particle shape of the zinc oxide powder obtained according to the aging temperature. (A) is 10 degreeC, (b) is 30 degreeC, and (c) is 50 degreeC.
Figure 7 shows the SEM photographs and particle size analysis results showing the particle shape of the zinc oxide powder obtained according to the aging time. (A) is 4 hours, (b) is 8 hours, and (c) is 12 hours.

Hereinafter, the present invention will be described in detail with reference to the following examples. However, the following examples are provided to aid understanding of the present invention, and the scope of the present invention is not limited to the following examples.

Example  1-9: Preparation of Zinc Oxide Fine Particle Powder

In this example, zinc ingot (purity 99.99%), 30% nitric acid solution (HNO ₃ ), and 28% aqueous ammonia (NH ₄ OH) were used as materials.

As shown in Table 1, zinc oxide fine particles were prepared by varying the neutralization conditions by pH value, neutralizing agent (ammonia) charge rate, aging temperature, and aging time in the neutralization step.

Example
number Neutralization condition pH Neutralization rate Aging temperature Ripening time One 5 5 wt% / min 30 ℃ 8 hours 2 5.5 5 wt% / min 30 ℃ 8 hours 3 6 5 wt% / min 30 ℃ 8 hours 4 5.5 2.5 wt% / min 30 ℃ 8 hours 5 5.5 10 wt% / min 30 ℃ 8 hours 6 5.5 5 wt% / min 10 ℃ 8 hours 7 5.5 5 wt% / min 50 ℃ 8 hours 8 5.5 5 wt% / min 30 ℃ 4 hours 9 5.5 5 wt% / min 30 ℃ 12 hours

Specifically, the batch reactor for the production of zinc oxide was used 200 L class (Fig. 1), was dissolved by putting 15 kg of zinc ingot in the reactor (1) containing the nitric acid solution. In the next step, ammonia water in the precipitant reservoir 2 was introduced at a constant rate through the flow rate controller 3 to neutralize the nitric acid solution to precipitate and produce a zinc oxide cake.

At this time, the molar ratio of nitric acid for dissolving zinc ingot was 1: 6 zinc and nitric acid. The nitric acid solution in which the zinc ingot was melted was introduced into the reactor at a feed rate of 2.5 wt%, 5.0 wt%, and 10.0 wt% of neutralizing ammonia water while stirring sufficiently at 200 rpm through the stirrer 4. The pH of the solution was adjusted to 5-6, and the pH change of the reaction solution was precisely measured by a pH meter during the synthesis reaction. In addition, the aging temperature was controlled in the range of 10 ~ 50 ℃ through the temperature controller (5), the aging time was changed to 4 hours, 8 hours, 12 hours.

The zinc oxide solid product in the form of a cake obtained in the dissolution and neutralization step was denitrated using a centrifugal dehydrator to remove nitric acid solution and ammonia water. The dehydrated zinc oxide cake was washed 15 times with ultrapure water (DI water) to remove all remaining nitric acid solution and ammonia water. After drying in the drying step using a drying oven for 12 hours at 100 ℃ evaporated all the water, such as ultrapure water used during the washing process. After drying, the large agglomerated mass was pulverized with a pestle, passed through 200 mesh, and then calcined at 300 ° C. for 4 hours in an electric furnace to further remove all impurities remaining during the reaction. Finally, the finely aggregated zinc oxide powder obtained in the previous step was disintegrated to separate the coagulated portions of the wet precipitate from each other through the high-pressure air jet of 6 kg air pressure.

Various zinc oxide fine particle powders obtained by different manufacturing process conditions in this embodiment were obtained through a dissolution / neutralization step, a dehydration step, a drying step, a calcining step, and a disintegration step. The steps are briefly shown in FIG. 2.

Experimental Example  1: Investigation of particle shape and size of zinc oxide fine particle powder

Crystal structure, particle size and particle size of the zinc oxide fine particle powder of Example 2 among the zinc oxide fine particle powders obtained in the above example were determined by using an X-ray diffractometer (XRD), an electron microscope (TEM, SEM), and a particle size analyzer. The shape was analyzed.

The results are shown in Fig.

In Figure 3, (a) shows the appearance of 50 nm milky white zinc oxide powder obtained in the present invention, (b) is a SEM picture (scale bar: 100 nm), (c) is XRD measurement results, (d) Shows a TEM photograph (scale bar: 50 nm).

As shown in FIG. 3, it was confirmed that a milky white zinc oxide powder present in a 50 nm nanoscale was obtained, and the final powder obtained through XRD analysis was a typical zinc oxide powder.

Experimental Example  2: pH  Impact Analysis on Change

During the production process of the zinc oxide fine particles, the pH changes due to the addition of the neutralizing agent, and serves as an important factor in determining the size and shape of the zinc oxide particles. The effects of ammonia water (NH ₄ OH), a neutralizing agent, and the pH of the zinc ingot solution dissolved in nitric acid were varied. In the present experimental example, the pH was adjusted from 3 to 8, and it was confirmed that particulates of zinc oxide were not produced when the pH was 5 or less and 6 or more in this region. In other words, the important pH range in which the zinc oxide fine particles are produced is between 5 and 6, and thus the fine particles of zinc oxide were prepared in three regions of 5, 5.5, and 6, and the size and shape thereof were analyzed.

As a result, SEM photographs and particle size analysis results of the zinc oxide produced in FIG. 4 are shown.

4, it can be seen that the particle behavior of zinc oxide according to pH is caused by a mixture of nucleation and particle growth according to pH, affecting the particle size distribution and particle size. In particular, when comparing the SEM photograph and the particle size distribution of the zinc oxide produced under the experimental conditions of the present experimental example, the zinc oxide produced at pH 5.5 shows a more fine particle size. In addition, looking at the particle size distribution by pH, it can be seen that the particle size distribution is the narrowest at pH 5.5. That is, it can be seen that the completeness of the precipitation for the zinc oxide particles is determined according to the range of the pH value of the solution.

Experimental Example  3: Analysis of the effect on the rate of neutralizer input

The effects on the particle size and shape of zinc oxide produced by adjusting the feed rate of ammonia water, a neutralizing agent, at 2.5 wt%, 5.0 wt% and 10 wt% per minute were investigated.

As a result, the SEM photograph and the particle size analysis result of the zinc oxide produced in FIG. 5 are shown.

As shown in FIG. 5, it was found that the shapes of the particles were all zinc oxide close to spherical. Spherical uniform particles of about 100 nm were formed at a rate of 2.5 wt% / min of ammonia water. In addition, it can be seen that non-uniform spherical particles of 50 to 100 nm were formed at 5.0 wt% / min, and 50 nm particles were formed at 10 wt% / min. In particular, the particle size distribution shows a particle size distribution having a very uniform particle size at 2.5 wt% / min. As a result, the particle size and particle size distribution were affected by the rate of ammonia water, which is a neutralizing agent. Can be.

Experimental Example  4: Analysis of influence on aging temperature

In this experimental example, the effect of aging temperature on neutralization was adjusted to 10 ° C, 30 ° C, and 50 ° C on the particle size and shape of zinc oxide.

As a result, SEM photographs and particle size analysis results of the zinc oxide produced in FIG. 6 are shown.

As shown in FIG. 6, when the aging temperature is 10 ° C., it can be seen that the particles have a nonuniform particle size of 50 to 200 nm, and when the temperature is 30 ° C., the particles have a nonuniform particle size of 50 to 300 nm. In addition, it can be seen that the aging temperature of 50 ℃ has a spherical particle shape of a uniform particle size of about 100 nm. From the particle size distribution results, it was found that the particle size distribution was wider at aging temperatures of 10 ° C and 30 ° C but narrower at 50 ° C. In other words, as the aging temperature increases through the present experimental example, it is possible to obtain a fine zinc oxide powder having a uniform particle size distribution, but does not significantly affect the particle size.

Experimental Example  5: Analysis of the influence on the ripening time

In this experimental example, experiments were carried out on the process parameters for the aging time, which affects the particle size and shape of the produced zinc oxide fine particles. At this time, the conditions of maturation time were changed to 4 hours, 8 hours, and 12 hours for comparative analysis.

As a result, the SEM photograph and the particle size analysis result of the zinc oxide produced in FIG. 7 are shown.

As shown in FIG. 7, when the aging time was 4 hours, spherical particles of about 100 nm and non-spherical particles of about 300 nm were mixed and produced, and spherical particles of 50 to 100 nm were produced at 8 hours. In particular, when the aging time was 12 hours, large size plate-shaped particles of 200 nm or more were produced. Therefore, when the aging time is 8 hours under the conditions used in this experimental example, it was confirmed that the zinc oxide fine particles could be produced smaller and more uniform than the shorter or longer one.

Experimental Example  6: Investigation of the yield of zinc oxide fine powders according to the molar ratio of zinc and nitric acid

In this experimental example, the production yield of zinc oxide fine powder was investigated according to the molar ratio of zinc and nitric acid (Zn: HNO ₃ ) used in the production of zinc oxide fine powder. At this time, the molar ratio of nitric acid to dissolve the zinc ingot was carried out in the range of 1: 4 to 1: 6 of zinc and nitric acid, and the treatment conditions of the neutralization step were the same as in Example 2.

The results are shown in Table 2 below.

Mole ratio Zn and ZnO (kg) Mass before heat treatment (kg) Mass after 30g heat treatment (kg) production
yield Zn Ingot
input ZnO
Estimated amount Sample 1 Sample 2 Average Remaining ratio after heat treatment 1: 4 1.16 1.4384 1.6 0.0217 0.0218 0.0217 0.7248 80.6% 1: 5 1.23 1.5252 2.066 0.0203 0.0203 0.0203 0.6777 91.8% 1: 6 1.07 1.3268 1.868 0.0197 0.0197 0.0197 0.6578 92.6%

As shown in the results of Table 2, the conditions used in the present invention show a maximum yield of 92.6% at a molar ratio of 1: 6. Through this, the larger the molar ratio, the zinc ingot is completely dissolved in nitric acid, which indicates that zinc oxide is easy to nucleate and grow particles.

Claims (10)

Method for producing a zinc oxide powder comprising the following steps:
Dissolving zinc ingot in aqueous nitric acid solution (step 1);
Adding ammonia water to the solution of step 1) to neutralize to obtain a zinc oxide solid product (step 2);
Dehydrating the zinc oxide solid product (step 3);
Drying the dehydrated zinc oxide solid product (step 4);
Calcining the dried zinc oxide solid product (step 5); And
Disintegrating the calcined zinc oxide solid product to obtain a zinc oxide powder (step 6).
The method of claim 1, wherein the molar ratio of zinc and nitric acid in step 1) is 1: 4 to 1: 6.
The method for preparing zinc oxide powder according to claim 1, wherein the pH of the step 2) is 5 to 6.
The method for preparing zinc oxide powder according to claim 1, wherein the rate of introducing ammonia water during neutralization of step 2) is 2.5 to 10.0 wt% / min.
The method of claim 1, wherein the aging temperature during neutralization of step 2) is 10 to 50 ℃.
The method of claim 1, wherein the aging time during neutralization of step 2) is 4 to 12 hours.
The method of claim 1, wherein the dehydration of step 3) is performed using a centrifugal dehydrator.
The method of claim 1, wherein the drying of step 4) is performed at 80 to 120 ° C. for 8 to 24 hours.
The method of claim 1, wherein the calcination of step 5) is performed at 250 to 400 ° C. for 2 to 6 hours.
The method of claim 1, wherein the disintegration of step 6) is performed by injecting air at an air pressure of 4 to 8 kg.

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