Zinc oxide whisker wet preparation method based on epsilon-zinc hydroxide low-temperature precursor

Abstract

The invention discloses a zinc oxide whisker wet preparation method based on an epsilon-zinc hydroxide low-temperature precursor, and belongs to the technical field of inorganic chemical material preparation. The preparation method comprises the following steps: by taking inorganic zinc salt and inorganic alkali as raw materials and adopting a two-step method, firstly, dropwise adding a zinc salt solution containing a dispersing agent into inorganic alkali liquor at the temperature of 5-25 DEG C to synthesize an epsilon-zinc hydroxide precursor with high dispersion and good alkali solubility, filtering and washing, adding the epsilon-zinc hydroxide precursor into the inorganic alkali liquor at the solid content of 12-30%, and drying to obtain the epsilon-zinc hydroxide. And reacting for 0.5-3 hours under the low-temperature hydrothermal condition of 60-150 DEG C by utilizing the synergistic effect of a dissolution promoter and a morphology regulating agent, and preparing the zinc oxide whisker with the average length of 2-15 microns, the average diameter of 100-500 nanometers, the length-diameter ratio of 15-80 and the main content of more than 98% of zinc oxide through an alkali dissolution conversion method. The method is simple in process, low in cost, efficient, easy to control and high in zinc yield (larger than or equal to 95%), and a mild and efficient new way is provided for wet-process zinc oxide whisker preparation.

Description

Technical Field

[0001] The present application relates to the field of inorganic chemical material preparation, and in particular, to a wet method for preparing zinc oxide whiskers based on an ε-zinc hydroxide low-temperature precursor. Background Art

[0002] China is the second largest zinc resource country and the world's largest zinc producer. The production capacity of the zinc metallurgical industry continues to expand, but it is mainly based on metallic zinc, amorphous zinc oxide and inorganic zinc salts. The zinc metallurgical industry has problems such as a single industrial structure and low industrial added value. Among the industrial products of metallic zinc, zinc oxide with a specific crystal structure has high added value and a wide range of uses as an industrial product. It is one of the directions for high value-added utilization of zinc resources. The crystal structure of zinc oxide is composed of zinc and oxygen atoms stacked alternately along the c-axis. The polar surface has the highest surface energy among many low-index crystal planes, making it easy to grow one-dimensionally along the c-axis. Therefore, zinc oxide has the characteristics of high elastic modulus and high tensile strength. It can be used as a high-end chemical additive and combined with plastics, rubbers, coatings, alloys, etc. to play the role of reinforcement, antistatic, antibacterial, and wave absorption. Zinc oxide is also a semiconductor material with a bandgap of 3.37eV and an electron excitation energy barrier of 60meV. It can also be used in advanced devices such as solar cells, nano-electromechanical, sensors, field emission, and lasers. It is used in the production of gas-sensitive materials, optoelectronic materials, and catalytic materials. Therefore, zinc oxide materials need to be further developed and applied. Summary of the invention

[0003] The present application includes a wet method for preparing zinc oxide whiskers based on an ε-zinc hydroxide low-temperature precursor.

[0004] In a first aspect of the present application, the present application proposes a method for preparing ε-zinc hydroxide, comprising: mixing a dispersant and a zinc salt aqueous solution in a mass ratio of (0.001-0.05):1 to obtain a dispersed zinc salt aqueous solution; adding the dispersed zinc salt aqueous solution dropwise to an inorganic alkali aqueous solution and mixing, wherein the molar ratio of the solute of the zinc salt aqueous solution to the solute of the inorganic alkali aqueous solution is 1:(1-4), and the reaction time is 0.5h-2h to obtain the ε-zinc hydroxide.

[0005] The method for preparing ε-zinc hydroxide proposed in the present application controls the feed ratio and reaction rate of the dispersant, zinc salt and inorganic base, so that the zinc salt and the inorganic base react to generate ε-zinc hydroxide having an orthorhombic crystal structure. Compared with amorphous zinc hydroxide, the crystal structure makes ε-zinc hydroxide have higher chemical stability in strong alkali and better alkali solubility, which is conducive to its further processing.

[0006] In some embodiments, the molar concentration of the zinc salt aqueous solution is 1 mol / L-4 mol / L.

[0007] In some embodiments, the molar concentration of the inorganic base aqueous solution is 1 mol / L-4 mol / L.

[0008] In some embodiments, the solute of the zinc salt aqueous solution includes at least one of zinc nitrate, zinc sulfate, zinc acetate, and zinc chloride. 2+ .

[0009] In some embodiments, the solute of the inorganic alkali aqueous solution includes at least one of sodium hydroxide, potassium hydroxide, and ammonia. - , to generate ε-zinc hydroxide.

[0010] In some embodiments, the stirring speed of the mixing process is 300rpm-600rpm. 2+ With OH - Full dispersion is beneficial to the dispersed generation of ε-zinc hydroxide.

[0011] In some embodiments, the temperature of the mixing process is 5° C.-25° C. Thus, the mixing process can achieve high stability and high solubility of the product.

[0012] In some embodiments, the dispersant includes at least one of sodium dodecyl sulfonate, sodium dodecylbenzene sulfonate, sodium dodecyl sulfate, hexadecyl trimethyl ammonium bromide, acetic acid, ethylenediamine tetraacetic acid, and polyethylene glycol. Thus, the crystal structure of ε-zinc hydroxide can be controlled. 2+ The complexation and barrier effect between Zn 2 + Disperse thoroughly in the solution.

[0013] In a second aspect of the present application, the present application proposes a method for preparing zinc oxide whiskers, comprising: mixing ε-zinc hydroxide with an alkaline solution to obtain a zinc hydroxide slurry, wherein the ε-zinc hydroxide is obtained by the method for preparing ε-zinc hydroxide proposed in the present application, and the solid mass fraction of the zinc hydroxide slurry is 12%-30%; mixing a morphology control agent, a dissolving agent, and the zinc hydroxide slurry to obtain a whisker growth slurry; and performing a whisker growth treatment on the whisker growth slurry to obtain the zinc oxide whiskers.

[0014] The method for preparing zinc oxide whiskers proposed in the present application utilizes the fact that low-temperature ε-zinc hydroxide has stable chemical properties in strong alkali and low solubility in water. After mixing with an alkaline solution, a higher solid mass fraction can be achieved in the alkaline solution. By utilizing the control effect of a morphology control agent and a solvent promoter on the formation of zinc oxide whiskers, ε-zinc hydroxide is converted into zinc oxide, and further one-dimensionally oriented zinc oxide whiskers are generated. The method for preparing zinc oxide whiskers can achieve a higher preparation efficiency, resulting in a higher utilization rate of zinc element raw materials.

[0015] In some embodiments, the mass ratio of the accelerator to the ε-zinc hydroxide is (0.001-0.16):1.

[0016] In some embodiments, the mass ratio of the morphology control agent to the ε-zinc hydroxide is (0.001-0.16):1.

[0017] In some embodiments, the molar concentration of the alkaline solution is 0.1 mol / L-1 mol / L.

[0018] In some embodiments, the temperature of the whisker growth treatment is 60° C.-150° C., and the time of the whisker growth treatment is 0.5 h-3 h. Thus, the growth of zinc oxide whiskers can be achieved at a relatively low temperature.

[0019] In some embodiments, the morphology control agent includes at least one of polyethanol, polyvinyl alcohol, sodium dodecyl sulfonate, hexadecyl trimethyl ammonium bromide, sodium dodecyl benzene sulfonate, sodium dodecyl sulfate, polyvinyl pyrrolidone, polyvinyl amide, and sodium polystyrene sulfonate. Thus, the whisker growth of zinc oxide in the radial direction can be suppressed to obtain one-dimensionally oriented zinc oxide whiskers.

[0020] In some embodiments, the dissolution agent includes at least one of ammonium chloride, sodium chloride, ammonium sulfate, and ammonium carbonate.

[0021] In a third aspect of the present application, the present application proposes a zinc oxide whisker, which is prepared by the method for preparing zinc oxide whiskers proposed in the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The above and / or additional aspects and advantages of the present application will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0023] Figure 1 A schematic diagram of a process for preparing zinc oxide whiskers in one embodiment of the present application;

[0024] Figure 2 This is a scanning electron microscope (SEM) image of ε-zinc hydroxide in Example 3 of the present application;

[0025] Figure 3 is the X-ray powder diffraction spectrum of ε-zinc hydroxide in Example 3 of the present application;

[0026] Figure 4 This is a SEM image of the zinc oxide whisker prepared in Example 3 of the present application;

[0027] Figure 5 This is the X-ray powder diffraction spectrum of the zinc oxide whisker prepared in Example 3 of the present application. DETAILED DESCRIPTION

[0028] The embodiments of the present application are described in detail below. Examples of the embodiments are shown in the drawings, but unnecessary detailed descriptions may be omitted. For example, detailed descriptions of well-known matters and repeated descriptions of actually identical structures may be omitted. This is to avoid the following description from becoming unnecessarily lengthy and to facilitate understanding by those skilled in the art. In addition, the drawings and the following description are provided for those skilled in the art to fully understand the present application and are not intended to limit the subject matter described in the claims.

[0029] Unless otherwise defined, all technical and scientific terms used in this application have the same meanings as those commonly understood by technicians in the technical field to which this application belongs; the terms used in this application are only for the purpose of describing specific embodiments and are not intended to limit this application; unless otherwise specified, the numerical values ​​of the parameters mentioned in this application can be measured using various measurement methods commonly used in the art (for example, they can be tested according to the methods given in the embodiments of this application).

[0030] The terms "including" and "having" in the specification and claims of the present application and any modifications thereof are open expressions, that is, including the contents specified in the present application but not excluding other contents.

[0031] In the description of this application, regardless of whether the words "about" or "approximately" are used, all the numbers disclosed herein are approximate values. The value of each number may differ by less than 10% or a reasonable difference considered by those skilled in the art, such as 1%, 2%, 3%, 4% or 5%.

[0032] "Scope" disclosed in the present application is limited in the form of lower limit and upper limit, and a given range is limited by selecting a lower limit and an upper limit, and the selected lower limit and upper limit define the boundary of a special range. The scope limited in this way can be including end values ​​or not including end values, and can be arbitrarily combined, that is, any lower limit can be combined with any upper limit to form a scope. For example, if the scope of 60-120 and 80-110 is listed for a specific parameter, it is understood that the scope of 60-110 and 80-120 is also expected. In addition, if the minimum range values ​​1 and 2 are listed, and if the maximum range values ​​3, 4 and 5 are listed, the following scope can be all expected: 1-3, 1-4, 1-5, 2-3, 2-4 and 2-5. In the present application, unless otherwise specified, the numerical range "ab" represents the abbreviation of any real number combination between a and b, wherein a and b are real numbers. For example, the numerical range "0-5" means that all real numbers between "0-5" are listed in this document, and "0-5" is just an abbreviation of these numerical combinations. In addition, when a parameter is expressed as an integer ≥ 2, it is equivalent to disclosing that the parameter is, for example, an integer of 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0033] Unless otherwise specified, all embodiments and optional embodiments of the present application can be combined with each other to form a new technical solution.

[0034] Unless otherwise specified, all technical features and optional technical features of this application can be combined with each other to form a new technical solution.

[0035] Zinc oxide can be prepared by gas phase method or liquid phase method. The basic principle of preparing zinc oxide by gas phase method is to evaporate zinc-based raw materials, such as metallic zinc, zinc-containing compounds or zinc oxide, at high temperature conditions of 800℃-1600℃, and control the morphology of zinc oxide whiskers by controlling process parameters such as raw material composition, atmosphere, catalyst, vacuum degree, etc. In the process of preparing zinc oxide by gas phase method, if high temperature roasting is used to evaporate the zinc-based raw materials, waste slag will be produced during the evaporation process. In addition, there is an incomplete reaction of zinc-based raw materials, resulting in unreacted zinc in the slag after the preparation of zinc oxide is completed, resulting in a waste of zinc-based raw materials and reducing the output of zinc oxide.

[0036] The basic principle of the liquid phase method is to use soluble zinc salt as raw material and inorganic base or OH that is easy to release -The organic reagent is used as a precipitant to prepare a zinc salt precursor, and then the zinc salt precursor is promoted by an auxiliary agent to control the further growth of zinc oxide. The liquid phase method for preparing zinc oxide whiskers has the characteristics of mild conditions, easy process control, and uniform product dispersion, which is suitable for large-scale production, but the preparation efficiency is often low, the solid mass fraction of zinc oxide is low, the amount of waste liquid is large, and the yield of zinc element is less than 20%. Therefore, the liquid phase method for preparing zinc oxide whiskers is still in the laboratory exploration stage, and there is no large-scale industrial production at home and abroad.

[0037] The present application includes a wet method for preparing zinc oxide whiskers based on an ε-zinc hydroxide low-temperature precursor.

[0038] In a first aspect of the present application, the present application proposes a method for preparing ε-zinc hydroxide, comprising: mixing a dispersant and a zinc salt aqueous solution in a mass ratio of (0.001-0.05):1 to obtain a dispersed zinc salt aqueous solution; adding the dispersed zinc salt aqueous solution dropwise to an inorganic alkali aqueous solution and mixing, wherein the molar ratio of the solute of the zinc salt aqueous solution to the solute of the inorganic alkali aqueous solution is 1:(1-4), and the reaction time is 0.5h-2h to obtain the ε-zinc hydroxide.

[0039] The method for preparing ε-zinc hydroxide proposed in this application is referred to Figure 2 and Figure 3 By controlling the feed ratio and reaction rate of the dispersant, zinc salt and inorganic base, the zinc salt and inorganic base react to generate ε-zinc hydroxide with orthorhombic crystal structure. Compared with amorphous zinc hydroxide, the crystal structure makes ε-zinc hydroxide have better chemical stability and alkali solubility in strong alkali. The properties of ε-zinc hydroxide make it suitable for more application scenarios, which is conducive to its further processing.

[0040] In some embodiments, the molar concentration of the zinc salt aqueous solution is 1 mol / L-4 mol / L.

[0041] In some embodiments, the molar concentration of the inorganic base aqueous solution is 1 mol / L-4 mol / L.

[0042] In some embodiments, the solute of the zinc salt aqueous solution includes at least one of zinc nitrate, zinc sulfate, zinc acetate, and zinc chloride. 2+ .

[0043] In some embodiments, the solute of the inorganic alkali aqueous solution includes at least one of sodium hydroxide, potassium hydroxide, and ammonia. - , to generate ε-zinc hydroxide.

[0044] In some embodiments, the stirring speed of the mixing process is 300rpm-600rpm. 2+ With OH - Full dispersion is beneficial to the dispersed generation of ε-zinc hydroxide.

[0045] In some embodiments, the temperature of the mixing process is 5° C.-25° C. Thus, the mixing process can achieve high stability and high solubility of the product.

[0046] In some embodiments, the dispersant includes at least one of sodium dodecyl sulfonate, sodium dodecylbenzene sulfonate, sodium dodecyl sulfate, hexadecyl trimethyl ammonium bromide, acetic acid, ethylenediamine tetraacetic acid, and polyethylene glycol. Thus, the crystal structure of ε-zinc hydroxide can be controlled. 2+ The complexation and barrier effect between Zn 2 + Disperse thoroughly in the solution.

[0047] In a second aspect of the present application, the present application proposes a method for preparing zinc oxide whiskers, comprising: mixing ε-zinc hydroxide with an alkaline solution to obtain a zinc hydroxide slurry, wherein the ε-zinc hydroxide is obtained by the method for preparing ε-zinc hydroxide proposed in the present application, and the solid mass fraction of the zinc hydroxide slurry is 12%-30%; mixing a morphology control agent, a dissolving agent, and the zinc hydroxide slurry to obtain a whisker growth slurry; and performing a whisker growth treatment on the whisker growth slurry to obtain the zinc oxide whiskers.

[0048] The method for preparing zinc oxide whiskers proposed in this application is referred to Figure 1, using the good chemical stability of low-temperature ε-zinc hydroxide in strong alkali and low solubility in water, after mixing with alkaline solution, ε-zinc hydroxide is used as a precursor to obtain zinc oxide whiskers through a dissolution-precipitation process. Because ε-zinc hydroxide can be dissolved in low-concentration alkaline solution, and the addition of a solvent promotes the dissolution process of ε-zinc hydroxide, the preparation process of zinc oxide whiskers can be carried out in a solution with a relatively low alkaline concentration. Because the solubility of zinc oxide decreases with the decrease in the concentration of the alkaline solution, the process of preparing zinc oxide whiskers is carried out in an environment of low-concentration alkaline solution, thereby making the solid mass fraction of zinc oxide whiskers precipitated higher. Combined with the control effect of morphology control agents on the formation of zinc oxide whiskers, such as the lateral synergistic adsorption effect of sulfonate (-SO3) and benzenesulfonate (-C6H5SO3) morphology control agents on zinc oxide whiskers, such as sulfonate adsorption (110) and benzenesulfonate adsorption (100), the radial whisker growth of zinc oxide is inhibited, and one-dimensional oriented zinc oxide whiskers are further generated. The method for preparing zinc oxide whiskers can achieve higher preparation efficiency, and the single-pass yield of zinc element can be greater than or equal to 95%.

[0049] In some embodiments, the solid mass fraction of the prepared zinc oxide whiskers in the total mass of the reaction solution is 10%-25%.

[0050] In some embodiments, the zinc oxide whiskers are filtered, washed and dried.

[0051] In some embodiments, the mass ratio of the accelerator to the ε-zinc hydroxide is (0.001-0.16):1.

[0052] In some embodiments, the mass ratio of the morphology control agent to the ε-zinc hydroxide is (0.001-0.16):1.

[0053] In some embodiments, the molar concentration of the alkaline solution is 0.1 mol / L-1 mol / L.

[0054] In some embodiments, the temperature of the whisker growth treatment is 60° C.-150° C., and the time of the whisker growth treatment is 0.5 h-3 h. Thus, the growth of zinc oxide whiskers can be achieved at a relatively low temperature.

[0055] In some embodiments, the morphology control agent includes at least one of polyethanol, polyvinyl alcohol, sodium dodecyl sulfonate, hexadecyl trimethyl ammonium bromide, sodium dodecyl benzene sulfonate, sodium dodecyl sulfate, polyvinyl pyrrolidone, polyvinyl amide, and sodium polystyrene sulfonate. Thus, the whisker growth of zinc oxide in the radial direction can be suppressed to obtain one-dimensionally oriented zinc oxide whiskers.

[0056] In some embodiments, the dissolution agent includes at least one of ammonium chloride, sodium chloride, ammonium sulfate, and ammonium carbonate.

[0057] In a third aspect of the present application, the present application proposes a zinc oxide whisker, which is prepared by the method for preparing zinc oxide whiskers proposed in the present application.

[0058] refer to Figure 4 and Figure 5 The zinc oxide whiskers have an average length of 2 μm-15 μm, an average diameter of 100 nm-500 nm, and an aspect ratio of 15-80. The mass fraction of zinc oxide in the zinc oxide whiskers is greater than or equal to 98%.

[0059] The scheme of the present application is described below by specific examples. It should be noted that the following examples are only used to illustrate the present application and should not be considered as limiting the scope of the present application. If no specific technology or conditions are specified in the examples, the technology or conditions described in the literature in this area or the product instructions are used. The reagents or instruments used are not specified by the manufacturer, and are all conventional products that can be obtained commercially.

[0060] Example 1

[0061] Preparation of ε-zinc hydroxide:

[0062] Hexadecyltrimethylammonium bromide and 1 mol / L zinc sulfate solution are mixed in a mass ratio of 0.001:1 to obtain a dispersed zinc salt aqueous solution; the dispersed zinc salt aqueous solution is added dropwise into a 3 mol / L sodium hydroxide solution at 25°C until the zinc-alkali ratio reaches 1:1, the stirring speed is maintained at 300 rpm, and after the reaction is completed, stirring is continued for 20 minutes to fully react, and after filtering, washing, and drying at room temperature, ε-zinc hydroxide is obtained as a precursor;

[0063] Preparation of zinc oxide whiskers:

[0064] Adding ε-zinc hydroxide as a precursor to a 0.5 mol / L sodium hydroxide solution until the solid content of the obtained zinc hydroxide slurry is 13%; adding 0.2 g of sodium sulfate and 0.4 g of polyvinyl pyrrolidone to the zinc hydroxide slurry under stirring, stirring and dissolving for 20 minutes to obtain a whisker growth slurry;

[0065] The whisker growth slurry was placed in a closed reactor and reacted at 100° C. for 3 hours. After the reaction was completed, it was cooled to room temperature, and the whisker growth slurry was filtered, washed, and dried.

[0066] The obtained zinc oxide whiskers have an average length of 7.5 micrometers, an average diameter of 250 nanometers, and an aspect ratio of 30. The zinc oxide solid content is 10%, and the single-pass yield is 96%.

[0067] Example 2

[0068] Preparation of ε-zinc hydroxide:

[0069] Ethylenediaminetetraacetic acid and 2 mol / L zinc chloride solution are mixed in a mass ratio of 0.003:1 to obtain a dispersed zinc salt aqueous solution; the dispersed zinc salt aqueous solution is added dropwise into a 2 mol / L potassium hydroxide solution at 15°C until the zinc-alkali ratio reaches 1:2, the stirring speed is maintained at 300 rpm, and after the reaction is completed, stirring is continued for 20 minutes to fully react, and ε-zinc hydroxide is obtained as a precursor after filtering, washing, and drying at room temperature;

[0070] Preparation of zinc oxide whiskers:

[0071] Adding ε-zinc hydroxide as a precursor to a 0.2 mol / L sodium hydroxide solution until the solid content of the obtained zinc hydroxide slurry is 13%; adding 0.1 g of ammonium sulfate and 0.5 g of polyacrylamide to the zinc hydroxide slurry under stirring, stirring and dissolving for 20 minutes to obtain a whisker growth slurry;

[0072] The whisker growth slurry was placed in a closed reactor and reacted at 150° C. for 1 hour. After the reaction was completed, the whisker growth slurry was cooled to room temperature, filtered, washed, and dried.

[0073] The obtained zinc oxide whiskers have an average length of 8 micrometers, an average diameter of 200 nanometers, an aspect ratio of 20, a zinc oxide solid content of 10%, and a single-pass yield of 96%.

[0074] Example 3

[0075] Preparation of ε-zinc hydroxide:

[0076] Sodium dodecylbenzene sulfonate and 2 mol / L zinc sulfate solution are mixed at a mass ratio of 0.005:1 to obtain a dispersed zinc salt aqueous solution; the dispersed zinc salt aqueous solution is added dropwise into a 4 mol / L sodium hydroxide solution at 10° C. until the zinc-alkali ratio reaches 1:2.5, the stirring speed is maintained at 300 rpm, and after the reaction is completed, stirring is continued for 20 minutes to fully react, and ε-zinc hydroxide is obtained as a precursor after filtering, washing, and drying at room temperature;

[0077] Preparation of zinc oxide whiskers:

[0078] Adding ε-zinc hydroxide as a precursor to a 1 mol / L sodium hydroxide solution until the solid content of the obtained zinc hydroxide slurry is 18%; adding 0.24 g of sodium dodecyl sulfate to the zinc hydroxide slurry under stirring, stirring and dissolving for 20 minutes to obtain a whisker growth slurry;

[0079] The whisker growth slurry was placed in a closed reactor and reacted at 80° C. for 2 hours. After the reaction was completed, the whisker growth slurry was cooled to room temperature, filtered, washed, and dried.

[0080] The obtained zinc oxide whiskers have an average length of 8 micrometers, an average diameter of 160 nanometers, an aspect ratio of 50, a zinc oxide solid content of 15%, and a single-pass yield of 97%.

[0081] Example 4

[0082] Preparation of ε-zinc hydroxide:

[0083] Sodium dodecyl sulfate and 1 mol / L zinc nitrate solution are mixed in a mass ratio of 0.005:1 to obtain a dispersed zinc salt aqueous solution; the dispersed zinc salt aqueous solution is added dropwise into a 4 mol / L sodium hydroxide solution at 5°C until the zinc-alkali ratio reaches 1:3, the stirring speed is maintained at 300 rpm, and after the reaction is completed, stirring is continued for 20 minutes to fully react, and ε-zinc hydroxide is obtained as a precursor after filtering, washing, and drying at room temperature;

[0084] Preparation of zinc oxide whiskers:

[0085] Adding ε-zinc hydroxide as a precursor to a 0.8 mol / L sodium hydroxide solution until the solid content of the obtained zinc hydroxide slurry is 22%; adding 0.05 g of ammonium chloride and 0.1 g of polyvinyl alcohol to the zinc hydroxide slurry under stirring, stirring and dissolving for 20 minutes to obtain a whisker growth slurry;

[0086] The whisker growth slurry was placed in a closed reactor and reacted at 120° C. for 1 hour. After the reaction was completed, the whisker growth slurry was cooled to room temperature, filtered, washed, and dried.

[0087] The obtained zinc oxide whiskers have an average length of 5 micrometers, an average diameter of 200 nanometers, an aspect ratio of 25, a zinc oxide solid content of 18%, and a single-pass yield of 98%.

[0088] Example 5

[0089] Preparation of ε-zinc hydroxide:

[0090] Hexadecyltrimethylammonium bromide and 1 mol / L zinc sulfate solution are mixed in a mass ratio of 0.004:1 to obtain a dispersed zinc salt aqueous solution; the dispersed zinc salt aqueous solution is added dropwise into a 2 mol / L sodium hydroxide solution at 20° C. until the zinc-alkali ratio reaches 1:2, the stirring speed is maintained at 300 rpm, and after the reaction is completed, stirring is continued for 20 minutes to fully react, and ε-zinc hydroxide is obtained as a precursor after filtering, washing, and drying at room temperature;

[0091] Preparation of zinc oxide whiskers:

[0092] Adding ε-zinc hydroxide as a precursor into a 0.5 mol / L sodium hydroxide solution until the solid content of the obtained zinc hydroxide slurry is 20%; adding 0.1 g of ammonium carbonate and 0.1 g of hexadecyltrimethylammonium bromide to the zinc hydroxide slurry under stirring, stirring and dissolving for 20 minutes to obtain a whisker growth slurry;

[0093] The whisker growth slurry was placed in a closed reactor and reacted at 110° C. for 2 hours. After the reaction was completed, the whisker growth slurry was cooled to room temperature, filtered, washed, and dried.

[0094] The obtained zinc oxide whiskers have an average length of 10 micrometers, an average diameter of 200 nanometers, an aspect ratio of 50, a zinc oxide solid content of 16%, and a single-pass yield of 97%.

[0095] Example 6

[0096] Preparation of ε-zinc hydroxide:

[0097] Polyethylene glycol 2000 and 2 mol / L zinc chloride solution are mixed in a mass ratio of 0.01:1 to obtain a dispersed zinc salt aqueous solution; the dispersed zinc salt aqueous solution is added dropwise into a 2 mol / L potassium hydroxide solution at 15° C. until the zinc-alkali ratio reaches 1:2, the stirring speed is maintained at 300 rpm, and after the reaction is completed, stirring is continued for 20 minutes to fully react, and ε-zinc hydroxide is obtained as a precursor after filtering, washing, and drying at room temperature;

[0098] Preparation of zinc oxide whiskers:

[0099] Adding ε-zinc hydroxide as a precursor to a 1 mol / L sodium hydroxide solution until the solid content of the obtained zinc hydroxide slurry is 24%; adding 0.15 g of ethylenediamine and 0.28 g of polyvinyl alcohol to the zinc hydroxide slurry under stirring, stirring and dissolving for 20 minutes to obtain a whisker growth slurry;

[0100] The whisker growth slurry was placed in a closed reactor and reacted at 70° C. for 3 hours. After the reaction was completed, the whisker growth slurry was cooled to room temperature, filtered, washed, and dried.

[0101] The obtained zinc oxide whiskers have an average length of 6 micrometers, an average diameter of 300 nanometers, an aspect ratio of 20, a zinc oxide solid content of 20%, and a single-pass yield of 99%.

[0102] Comparative Example 1

[0103] Preparation of ε-zinc hydroxide:

[0104] Sodium dodecylbenzene sulfonate and 2 mol / L zinc sulfate solution are mixed at a mass ratio of 0.005:1 to obtain a dispersed zinc salt aqueous solution; the dispersed zinc salt aqueous solution is added dropwise into a 4 mol / L sodium hydroxide solution at 10° C. until the zinc-alkali ratio reaches 1:2.5, the stirring speed is maintained at 300 rpm, and after the reaction is completed, stirring is continued for 20 minutes to fully react, and ε-zinc hydroxide is obtained as a precursor after filtering, washing, and drying at room temperature;

[0105] Preparation of zinc oxide whiskers:

[0106] Adding ε-zinc hydroxide as a precursor to a 4 mol / L sodium hydroxide solution until the solid content of the obtained zinc hydroxide slurry is 18%; adding 0.24 g of sodium dodecyl sulfate to the zinc hydroxide slurry under stirring, stirring and dissolving for 20 minutes to obtain a whisker growth slurry;

[0107] The whisker growth slurry was placed in a closed reactor and reacted at 80° C. for 2 hours. After the reaction was completed, the whisker growth slurry was cooled to room temperature, filtered, washed, and dried.

[0108] The obtained zinc oxide whiskers have an average length of 8 micrometers, an average diameter of 200 nanometers, an aspect ratio of 40, a zinc oxide solid content of 9%, and a single-pass yield of 64%.

[0109] In the description of the present application, "A and / or B" may include the case of A alone, the case of B alone, or any of the cases of A and B, where A and B are only used for examples and may be any technical feature connected by "and / or" in the present application.

[0110] In the present application, the writing order of each step does not mean a strict execution order and does not constitute any limitation on the implementation process. The specific execution order of each step should be determined by its function and possible internal logic. If there is no special explanation, all steps of the present application can be performed sequentially or randomly, preferably sequentially. For example, the method includes steps (a) and (b), indicating that the method may include steps (a) and (b) performed sequentially, or may include steps (b) and (a) performed sequentially. For example, the method may also include step (c), indicating that step (c) can be added to the method in any order, for example, the method may include steps (a), (b) and (c), or may include steps (a), (c) and (b), or may include steps (c), (a) and (b), etc.

[0111] It should be noted that the present application is not limited to the above-mentioned embodiments. The above-mentioned embodiments are only examples, and the embodiments having the same structure as the technical idea and exerting the same effect within the scope of the technical solution of the present application are all included in the technical scope of the present application. In addition, without departing from the scope of the main purpose of the present application, various modifications that can be thought of by those skilled in the art to the embodiments and other methods of combining some of the constituent elements in the embodiments are also included in the scope of the present application.

Claims

1. A method for preparing ε-zinc hydroxide, characterized in that: include: The dispersant and the zinc salt aqueous solution are mixed in a mass ratio of (0.001-0.05):1 to obtain a dispersed zinc salt aqueous solution; The dispersed zinc salt aqueous solution is added dropwise to the inorganic alkali aqueous solution and mixed, wherein the molar ratio of the solute of the zinc salt aqueous solution to the solute of the inorganic alkali aqueous solution is 1:(1-4), and the reaction time is 0.5h-2h to obtain the ε-zinc hydroxide.

2. The method according to claim 1, characterized in that The molar concentration of the zinc salt aqueous solution is 1 mol / L-4 mol / L; and / or, The molar concentration of the inorganic alkali aqueous solution is 1 mol / L-4 mol / L.

3. The method according to claim 2, characterized in that The solute of the zinc salt aqueous solution includes at least one of zinc nitrate, zinc sulfate, zinc acetate and zinc chloride; and / or, The solute of the inorganic alkali aqueous solution includes at least one of sodium hydroxide, potassium hydroxide and ammonia.

4. The method according to any one of claims 1 to 3, characterized in that: The stirring speed of the mixing process is 300rpm-600rpm; and / or, The temperature of the mixing treatment is 5°C-25°C.

5. The method according to any one of claims 1 to 3, characterized in that: The dispersant includes at least one of sodium dodecyl sulfonate, sodium dodecylbenzene sulfonate, sodium dodecyl sulfate, hexadecyltrimethylammonium bromide, acetic acid, ethylenediaminetetraacetic acid, and polyethylene glycol.

6. A method for preparing zinc oxide whiskers, characterized in that: include: Mixing ε-zinc hydroxide with an alkaline solution to obtain a zinc hydroxide slurry, wherein the ε-zinc hydroxide is obtained by the method according to any one of claims 1 to 5, and the solid mass fraction of the zinc hydroxide slurry is 12% to 30%; Mixing a morphology control agent, a dissolving agent, and the zinc hydroxide slurry to obtain a whisker growth slurry; The whisker growth slurry is subjected to a whisker growth treatment to obtain the zinc oxide whiskers.

7. The method according to claim 6, characterized in that The mass ratio of the dissolution agent to the ε-zinc hydroxide is (0.001-0.16):1; and / or, The mass ratio of the morphology control agent to the ε-zinc hydroxide is (0.001-0.16):

1.

8. The method according to claim 6 or 7, characterized in that: The molar concentration of the alkaline solution is 0.1 mol / L-1 mol / L; and / or, The temperature of the whisker growth treatment is 60° C.-150° C., and the time of the whisker growth treatment is 0.5 h-3 h.

9. The method according to claim 6 or 7, characterized in that: The morphology control agent includes at least one of polyethanol, polyvinyl alcohol, sodium dodecyl sulfonate, hexadecyltrimethylammonium bromide, sodium dodecylbenzene sulfonate, sodium dodecyl sulfate, polyvinyl pyrrolidone, polyvinyl amide, and sodium polystyrene sulfonate; and / or, The dissolution promoter includes at least one of ammonium chloride, sodium chloride, ammonium sulfate and ammonium carbonate.

10. A zinc oxide whisker, characterized in that: The method is prepared by any one of claims 6 to 9.

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