Preparation method of low-apparent-density black nano zirconium oxide granulated powder

Abstract

The invention relates to the technical field of ceramic materials, and discloses a preparation method of low-apparent-density black nano zirconium oxide granulation powder, a volatile agent is introduced into a formula, so that fine holes can be formed by high-temperature volatilization of the volatile agent in the granulation process, and the low-apparent-density black nano zirconium oxide granulation powder is prepared. Therefore, the black nano zirconium oxide granulation powder with low apparent density can be prepared, the powder consumption can be relatively reduced, the high requirement of the market on light and thin products can be met, the production cost is effectively reduced, and the market competitiveness of the products is enhanced.

Description

Technical Field

[0001] The invention relates to the technical field of ceramic materials, and in particular to a method for preparing black nano zirconium oxide granulated powder with low bulk density. Background Art

[0002] At present, the production formula of black nano zirconium oxide granulated powder and the granulated powder produced by the process generally used in the industry, when used for product pressing, significantly lead to an increase in the thickness and quality of the pressed product. Furthermore, in the subsequent sintering stage, a large amount of excess material must be removed through a series of complex and tedious processing steps to meet the normal product size specifications and appearance requirements. This series of additional processing steps greatly increases the material and processing costs, especially for products with relatively thin size requirements. The high production cost makes it difficult for the product to maintain its price advantage in the fierce market competition, thereby weakening its market competitiveness.

[0003] When we delved into the root cause of the excessive thickness of the existing black nano-zirconia granulated powder pressed products, we found that this was mainly due to the excessive mass of the powder loaded in the mold during the production process. According to the mass, density, and volume relationship m=ρV, we have tried to reduce the thickness of the product by reducing the volume of the mold. However, the results of this attempt were not significant, and the product thickness was only reduced by about 20%. What is more unfavorable is that this excessive thinning measure has also caused a series of new problems, such as the decrease in the strength of the green body of the product, easy cracking after demolding, and uneven pressure transmission of the press, all of which have adverse effects on the quality and performance of the product. Another exploration direction is to keep the mold volume V unchanged, and instead reduce the loose density of the granulated powder to achieve product thinning and weight reduction. This strategy has been proven to be effective.

[0004] Therefore, next, we urgently need to develop a new process method to prepare black nano-zirconia granulated powder with low bulk density to meet the market's high demand for light and thin products, effectively reduce production costs, and enhance the market competitiveness of products.

[0005] The above information is presented as background information only to assist with understanding the present disclosure and no determination or admission is made as to whether any of the above may be used as prior art with respect to the present disclosure. Summary of the invention

[0006] The invention provides a method for preparing black nano zirconium oxide granulated powder with low bulk density, so as to solve the problems existing in the prior art.

[0007] To achieve the above object, the present invention provides the following technical solutions:

[0008] A method for preparing black nano zirconium oxide granulated powder with low bulk density, the method comprising:

[0009] preparing a black granulation powder slurry;

[0010] Prepare black granulation powder glue; the black granulation powder glue includes a volatile agent;

[0011] The black granulation powder slurry is continuously stirred, and the black granulation powder glue is added dropwise into the black granulation powder slurry to obtain a second mixed slurry;

[0012] Shearing and dispersing the second mixed slurry to obtain a high-viscosity slurry;

[0013] The high-viscosity slurry is granulated to obtain black nano zirconium oxide granulated powder with low bulk density.

[0014] Furthermore, in the method for preparing black nano zirconium oxide granulated powder with low bulk density, the step of preparing black granulated powder slurry comprises:

[0015] Adding white yttrium-stabilized zirconia calcined powder and calcined black pigment powder into a drum ball mill, adding a certain amount of dispersant and pure water, and ball milling to obtain a first mixed slurry that is uniform and well dispersed;

[0016] The first mixed slurry is sand-milled to obtain a homogeneous slurry, namely a black granulated powder slurry.

[0017] Furthermore, in the method for preparing the low bulk density black nano zirconium oxide granulated powder, the yttrium content of the white yttrium-stabilized zirconium oxide calcined powder is 2-3% mol; the particle size D10 is 0.05-0.08 μm, D50 is 0.1-0.2 μm, and D90 is 0.3-0.4 μm;

[0018] The calcined black pigment powder has pigment components of several compounds of iron, cobalt, nickel, manganese, titanium, aluminum, vanadium and chromium; the particle size: D10 is 0.1-0.2 μm, D50 is 0.4-0.5 μm, and D90 is 0.7-0.8 μm.

[0019] Furthermore, in the method for preparing the low bulk density black nano zirconium oxide granulated powder, the first mixed slurry is ball-milled for 2-4 hours; the size of the grinding medium is φ3 mm, and the material is zirconium oxide; the ball-to-material weight ratio is 3:1; the amount of the white yttrium-stabilized zirconium oxide calcined powder is 95%-97%wt, the amount of the calcined black colorant powder is 3%-5%wt, the amount of the dispersant is 0.3%wt-0.6%wt, the slurry solid content is 40%-50%, and the drum ball mill frequency is 50-80Hz;

[0020] The number of sand milling rounds is 6-8; the grinding medium size is φ0.3-0.4 mm, and the material is zirconium oxide; the main engine speed of the sand mill is 600-800 r / min; the particle size of the black granulation powder slurry is D50<0.15, D90<0.5 μm.

[0021] Furthermore, in the method for preparing the low bulk density black nano zirconium oxide granulated powder, the step of preparing the black granulated powder glue comprises:

[0022] Adding a binder and a volatile agent into a stirrer for mixing to obtain a first glue;

[0023] Adding thickener and pure water into a stirrer and mixing them to obtain a second glue;

[0024] The first glue and the second glue are added into a stirrer for mixing to obtain a uniform third glue, namely, black granulated powder glue.

[0025] Furthermore, in the method for preparing the low bulk density black nano zirconium oxide granulated powder, when mixing the binder and the volatile agent, the frequency of the stirrer is 40-50 Hz, the pressure is 500-600 Bar, and the stirring time is 2-4 hours;

[0026] When mixing the thickener and the pure water, the frequency of the stirrer is 40-50 Hz, the pressure is 500-600 Bar, and the stirring time is 6-8 hours;

[0027] When mixing the first glue and the second glue, the frequency of the stirrer is 40-50 Hz, the pressure is 600-700 Bar, and the stirring time is 1-2 hours.

[0028] Furthermore, in the method for preparing the low bulk density black nano zirconium oxide granulated powder, the binder is at least one of aqueous polyacrylic acid, polyvinyl alcohol, and polyethylene glycol, with a content of 2%wt-4%wt; the volatile agent is a low boiling point alcohol, with a content of 2%wt-5%wt;

[0029] The thickener is at least one of sodium carboxymethyl cellulose, guar gum, xanthan gum and polyacrylic acid, and the amount used is 0.1-0.5%wt;.

[0030] Furthermore, in the method for preparing the low bulk density black nano zirconium oxide granulated powder, the step of continuously stirring the black granulated powder slurry and adding the black granulated powder glue droplets into the black granulated powder slurry to obtain the second mixed slurry is:

[0031] The black granulation powder slurry is added into a high-pressure homogenizer and stirred continuously, and the black granulation powder glue is added dropwise into the black granulation powder slurry through a peristaltic pump to obtain a second mixed slurry;

[0032] The dropping time is 3-4 hours, the frequency of the high-pressure homogenizer is 50-60 Hz, the pressure is 600-700 Bar, and the speed of the peristaltic pump is 40-80 r / min.

[0033] Furthermore, in the method for preparing the low bulk density black nano zirconium oxide granulated powder, the step of shearing and dispersing the second mixed slurry to obtain a high viscosity slurry is:

[0034] Using a high-speed shear disperser to shear and disperse the second mixed slurry to obtain a high-viscosity slurry;

[0035] The rotation speed of the dispersion disk is 3000-5000 r / min, the dispersion time is 5-10 min, and the viscosity of the high-viscosity slurry is 500-1000 mPa∙s.

[0036] Furthermore, in the method for preparing the black nano zirconium oxide granulated powder with low bulk density, the step of granulating the high viscosity slurry to obtain the black nano zirconium oxide granulated powder with low bulk density is:

[0037] The high-viscosity slurry is granulated using a centrifugal spray granulation dryer to obtain low bulk density black nano zirconium oxide granulated powder;

[0038] Among them, the inlet air temperature is adjusted to 200-220℃, the outlet temperature is 96-105℃, and the atomization frequency is 30-35Hz.

[0039] Compared with the prior art, the present invention has the following beneficial effects:

[0040] The present invention provides a method for preparing black nano zirconium oxide granulated powder with low bulk density, which is a brand-new process method. By introducing a volatile agent into the formula, the volatile agent can be volatilized at high temperature during the granulation process to leave tiny holes, thereby being able to prepare black nano zirconium oxide granulated powder with low bulk density. This method can not only reduce the amount of powder used, but also meet the market's high demand for light and thin products, effectively reduce production costs, and enhance the market competitiveness of products.

[0041] The present invention has other features and advantages, which will be apparent from or will be described in detail in the accompanying drawings and the following detailed description incorporated herein, which together serve to explain the specific principles of the invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0043] Figure 1 It is a schematic flow chart of a method for preparing black nano zirconium oxide granulated powder with low bulk density provided by an embodiment of the present invention;

[0044] Figure 2 is a schematic diagram of a granulation ball of an experimental example mentioned in an embodiment of the present invention;

[0045] Figure 3 Schematic diagram of the granulated balls of the comparative example mentioned in the embodiment of the present invention;

[0046] Figure 4 is a schematic diagram of the crushing effect of the experimental example mentioned in the embodiment of the present invention;

[0047] Figure 5 is a schematic diagram of the crushing effect of the comparative example mentioned in the embodiment of the present invention;

[0048] Figure 6 is a schematic diagram of the surface of a finished product of an experimental example mentioned in an embodiment of the present invention;

[0049] Figure 7 It is a schematic diagram of the finished product surface of the comparative example mentioned in the embodiment of the present invention. DETAILED DESCRIPTION

[0050] In order to explain in detail the possible application scenarios, technical principles, specific schemes that can be implemented, and the purposes and effects that can be achieved, the following is a detailed description of the specific embodiments listed in conjunction with the accompanying drawings. The embodiments described herein are only used to more clearly illustrate the technical solutions of the present application, and are therefore only used as examples, and cannot be used to limit the scope of protection of the present application.

[0051] Reference to "embodiment" herein means that the specific features, structures or characteristics described in conjunction with the embodiment may be included in at least one embodiment of the present application. The term "embodiment" appearing in various places in the specification does not necessarily refer to the same embodiment, nor does it particularly limit its independence or association with other embodiments. In principle, in the present application, as long as there is no technical contradiction or conflict, the various technical features mentioned in the embodiments can be combined in any way to form a corresponding implementable technical solution.

[0052] Unless otherwise defined, the technical terms used in this document have the same meanings as those generally understood by those skilled in the art to which this application belongs; the use of relevant terms in this document is only for describing specific embodiments and is not intended to limit this application.

[0053] In the description of this application, the term "and / or" is an expression used to describe the logical relationship between objects, indicating that three relationships may exist, for example, A and / or B, which means: A exists, B exists, and A and B exist at the same time. In addition, the character " / " in this article generally indicates that the objects before and after are in an "or" logical relationship.

[0054] In the present application, terms such as “first” and “second” are merely used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship of quantity, priority or sequence between these entities or operations.

[0055] Without further limitations, in this application, the words "include", "comprises", "has" or other similar expressions used in the sentences are intended to cover non-exclusive inclusion. These expressions do not exclude the presence of additional elements in the process, method or product including the elements, so that the process, method or product including a series of elements may include not only those limited elements, but also other elements not explicitly listed, or also include elements inherent to such process, method or product.

[0056] In this application, expressions such as "greater than", "less than", "exceed" and the like are understood to exclude the number itself; expressions such as "above", "below", "within" and the like are understood to include the number itself. In addition, in the description of the embodiments of this application, "multiple" means more than two (including two), and similar expressions related to "multiple" are also understood in this way, such as "multiple groups", "multiple times", etc., unless otherwise clearly and specifically limited.

[0057] In the description of the embodiments of the present application, space-related expressions used, such as "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "vertical", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicate the orientation or position relationship based on the orientation or position relationship shown in the specific embodiments or drawings, and are only for the convenience of describing the specific embodiments of the present application or facilitating the reader's understanding, and do not indicate or imply that the referred device or component must have a specific position, a specific orientation, or be constructed or operated in a specific orientation, and therefore cannot be understood as a limitation on the embodiments of the present application.

[0058] Unless otherwise expressly specified or limited, in the description of the embodiments of the present application, the terms such as "install", "connect", "connect", "fix", "set", etc. used should be understood in a broad sense. For example, the "connection" can be a fixed connection, a detachable connection, or an integrated setting; it can be a mechanical connection, an electrical connection, or a communication connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium; it can be the internal connection of two elements or the interaction relationship between two elements. For technicians in the technical field to which the present application belongs, the specific meanings of the above terms in the embodiments of the present application can be understood according to the specific circumstances.

[0059] Please refer to Figure 1 , is a schematic flow chart of a method for preparing a black nano zirconium oxide granulated powder with low bulk density provided in Example 1 of the present invention, which is suitable for preparing a black nano zirconium oxide granulated powder with low bulk density. The method specifically comprises the following steps:

[0060] S101, preparing black granulation powder slurry.

[0061] It should be noted that this step is the starting point of the preparation process, and its main purpose is to prepare the black granulation powder slurry so that the subsequent steps can proceed smoothly.

[0062] In a specific implementation of this embodiment, step S101 is further refined to include the following more detailed steps to ensure the uniformity, dispersion and particle size control of the slurry, laying a solid foundation for the subsequent granulation process.

[0063] Adding white yttrium-stabilized zirconia calcined powder and calcined black pigment powder into a drum ball mill, adding a certain amount of dispersant and pure water, and ball milling to obtain a first mixed slurry that is uniform and well dispersed;

[0064] The first mixed slurry is sand-milled to obtain a homogeneous slurry, namely a black granulated powder slurry.

[0065] It should be noted that, first, white yttrium-stabilized zirconia calcined powder and calcined black pigment powder are added to a drum ball mill in a predetermined ratio. These two powders are the main raw materials for preparing black nano zirconium oxide granulated powder, in which white yttrium-stabilized zirconia provides the main structure of the material, while calcined black pigment powder gives the material the desired color. Subsequently, a certain amount of dispersant is added to the ball mill. The function of the dispersant is to prevent the powder particles from agglomerating during the ball milling process and ensure the uniform dispersion of the slurry. Pure water is added as a ball milling medium, and then ball milling is performed. The purpose of ball milling is to refine the powder particles and disperse them evenly in water to form a preliminary first mixed slurry. Then, the preliminary first mixed slurry is sent to a sand mill for further refinement. Sand milling is an efficient particle refinement method that further refines the particles through the friction and shearing action between the high-speed rotating grinding wheel and the slurry.

[0066] In one implementation of this embodiment, the yttrium content of the white yttrium-stabilized zirconia calcined powder is 2-3% mol; the particle size D10 is 0.05-0.08 μm, D50 is 0.1-0.2 μm, and D90 is 0.3-0.4 μm;

[0067] It should be noted that yttrium, as a stabilizer, can effectively improve the phase stability of zirconia and prevent it from undergoing phase change at high temperatures, thereby affecting the performance of the material.

[0068] The particle size D10 is 0.05-0.08μm, D50 is 0.1-0.2μm, and D90 is 0.3-0.4μm. This particle size distribution range ensures the uniformity of the powder particles, which is beneficial to the subsequent ball milling, sand milling and granulation processes, and also helps to improve the density and performance of the final product.

[0069] In one implementation of this embodiment, in the calcined black pigment powder, the pigment components are several compounds of iron, cobalt, nickel, manganese, titanium, aluminum, vanadium, and chromium; the particle size: D10 is 0.1-0.2μm, D50 is 0.4-0.5μm, and D90 is 0.7-0.8μm.

[0070] It should be noted that the colorant ingredients are several compounds of iron, cobalt, nickel, manganese, titanium, aluminum, vanadium, and chromium. These compounds, as colorants, can give the zirconium oxide material the desired black color. Different combinations and contents of the compounds can adjust the color and hue of the final product.

[0071] The particle size D10 is 0.1-0.2μm, D50 is 0.4-0.5μm, and D90 is 0.7-0.8μm. This particle size distribution range ensures the uniform dispersion of the pigment powder and is conducive to forming a good color distribution in the zirconia matrix.

[0072] The high quality and performance of the raw materials are ensured by the detailed characterization of the white yttrium stabilized zirconia calcined powder and the calcined black pigment powder. These raw materials will provide a solid foundation for the subsequent preparation process, thus ensuring the low bulk density, excellent physical properties and good color effect of the final product.

[0073] In a specific implementation of this embodiment, the operating parameters of the two key steps of pure water ball milling and sand milling are defined in detail to ensure the uniformity, dispersion and particle size control of the slurry and provide high-quality raw materials for the subsequent granulation process.

[0074] Pure water ball milling step parameters:

[0075] Ball milling time: The time for ball milling the first mixed slurry is set to 2-4 hours. This time range ensures that the powder particles are fully refined and dispersed in water, while avoiding equipment wear and increased energy consumption that may be caused by ball milling for too long.

[0076] Grinding medium size and material: The grinding medium size is φ3mm, and the material is zirconium oxide. Zirconium oxide grinding medium has high hardness, high wear resistance and chemical stability, which can effectively improve the ball milling efficiency while avoiding contamination of the slurry.

[0077] Ball-to-powder weight ratio: Ball-to-powder weight ratio is set at 3:1. This ratio ensures sufficient contact and collision between the grinding medium and the powder, which is conducive to the refinement of powder particles.

[0078] Raw material dosage: The dosage of white yttrium stabilized zirconia calcined powder is 95%-97%wt, and the dosage of calcined black pigment powder is 3%-5%wt. This ratio range ensures the color effect and physical properties of the final product.

[0079] Dispersant dosage: The dosage of dispersant is 0.3%wt-0.6%wt. An appropriate amount of dispersant can effectively prevent the agglomeration of powder particles during ball milling and improve the dispersibility of the slurry.

[0080] Slurry solid content: The slurry solid content is set at 40%-50%. Appropriate solid content is conducive to the subsequent sand grinding and granulation process, and can ensure the fluidity of the slurry.

[0081] Drum ball mill frequency: The drum ball mill frequency is set at 50-80Hz. Appropriate frequency can improve the ball milling efficiency while avoiding excessive load on the equipment.

[0082] Sanding step parameters

[0083] Sanding rounds: The number of sanding rounds is set to 6-8 rounds. Multiple rounds of sanding can further refine the particles in the slurry and improve the uniformity of the particle size.

[0084] Grinding medium size and material: The grinding medium size for sand grinding is φ0.3-0.4mm, and the material is also zirconium oxide. This size of grinding medium is conducive to forming finer particles during the sand grinding process.

[0085] Sand mill main engine speed: The main engine speed of the sand mill is set at 600-800r / min. The appropriate speed can ensure sufficient contact and collision between the grinding medium and the slurry, and improve the sanding efficiency.

[0086] Slurry particle size: After sand grinding, the particle size of the black granulation powder slurry meets the strict requirements of D50 < 0.15μm and D90 < 0.5μm. This particle size range ensures the homogeneity of the slurry, which is beneficial to the subsequent granulation process and the performance of the final product.

[0087] S102, preparing black granulation powder glue; the black granulation powder glue includes a volatile agent.

[0088] It should be noted that in this step, black granulation powder glue needs to be prepared. This glue not only contains ingredients for enhancing the bonding force between particles, but also specially added volatile agents. The selection and dosage of volatile agents are crucial to the bulk density and performance of the final product. Volatile agents can evaporate quickly at high temperatures, thereby forming tiny pores during the granulation process and reducing the bulk density.

[0089] In a specific implementation of this embodiment, the preparation process of the black granulated powder glue is refined into three key steps to ensure the uniformity, stability and required performance of the glue. The following is a detailed explanation of these steps:

[0090] Step 1: Prepare the first glue

[0091] Operation: First, add the binder and the propellant into the mixer. The binder provides binding force between particles to ensure that the particles can be tightly combined during the granulation process. The propellant is used to form tiny pores in the subsequent process to reduce the bulk density.

[0092] Mixing: The binder and the volatile agent are fully mixed by the stirring action of the stirrer to obtain the first glue. The key to this step is to ensure the uniform mixing between the two so that the subsequent steps can proceed smoothly.

[0093] Step 2: Prepare the second glue

[0094] Operation: Next, add the thickener and pure water to another mixer. The thickener increases the viscosity of the glue so that it can better adhere to the surface of the particles. It also helps control the fluidity of the slurry. Appropriate viscosity can improve the suspension of the slurry. Pure water is used as a solvent to fully swell the thickener for easy mixing and subsequent operation.

[0095] Mixing: Also through the stirring action of the stirrer, the thickener can be fully swelled and mixed evenly in pure water to obtain the second glue. This step also needs to ensure the uniformity of mixing to ensure the performance of the final glue.

[0096] Step 3: Merge and Homogenize

[0097] Operation: Finally, add the first glue and the second glue into the same mixer for mixing. The purpose of this step is to combine the two glues to form a black granulated powder glue with the desired properties.

[0098] Mixing and homogenization: Through the strong stirring action of the agitator, the two glues are fully mixed and uniformly obtained to obtain a uniform third glue, that is, black granulated powder glue. The key to this step is to ensure the complete mixing between the two glues and the uniformity and stability of the final glue.

[0099] Through the above refinement steps, a black granulation powder glue with the required properties was successfully formulated. This glue provides a high-quality raw material basis for subsequent steps (such as adding glue to the slurry, shear dispersion and granulation), ensuring the low bulk density and excellent performance of the final product.

[0100] In a specific implementation of this embodiment, for the three key steps of mixing the binder and the propellant, the thickener and the pure water, and the first glue and the second glue, the operating parameters of the agitator are defined in detail, including the frequency, pressure and stirring time, to ensure the uniformity, stability and efficiency of the mixing process.

[0101] When mixing the binder and the propellant, the stirrer frequency is set to 40-50Hz. This frequency range ensures that the stirrer can provide sufficient power to fully mix the binder and the propellant. Pressure is set to 500-600Bar. Appropriate pressure helps to accelerate the mixing process while ensuring the uniformity of the mixture. Stirring time is set to 2-4h. This time range ensures that there is enough time for the binder and the propellant to be fully mixed to achieve the required uniformity.

[0102] When mixing thickener and pure water, stirrer frequency: also set to 40-50Hz. As in step 1, this frequency range ensures that the thickener can fully swell in pure water. Pressure: set to 500-600Bar. As in step 1, appropriate pressure helps to accelerate the mixing process and improve mixing efficiency. Stirring time: set to 6-8h. Compared with step 1, the stirring time of this step is longer. This is because the mixing between the thickener and pure water is a process of full swelling first and then mixing evenly, so it takes longer to achieve the required viscosity and uniformity.

[0103] When mixing the first glue and the second glue, the frequency of the stirrer is set to 40-50Hz. As in the previous two steps, this frequency range ensures that the two glues can be fully mixed. Pressure: set to 600-700Bar. Compared with the previous two steps, the pressure in this step is higher, which is to accelerate the mixing process between the two glues and ensure the uniformity and stability of the final glue. Stirring time: set to 1-2h. This time range ensures that there is enough time for the two glues to be fully mixed to achieve the desired performance.

[0104] The uniformity, stability and efficiency of the mixing process are ensured by the detailed definition of the operating parameters of the agitator.

[0105] In a specific implementation of this embodiment, the preparation of black granulated powder glue involves multiple key components, including a binder, a volatile agent, a thickener, and the overall mass fraction of the second glue. The selection and content of these components have a crucial impact on the performance of the final product. The following is a detailed description of these components:

[0106] The binder composition is at least one of water-based polyacrylic acid, polyvinyl alcohol and polyethylene glycol. These binders have good bonding properties and dispersibility, and can effectively bind the particles together to form stable granulated powder.

[0107] The content of the binder is 2%wt-4%wt. This content range ensures that the binder can be evenly distributed in the slurry and provides sufficient bonding force to ensure the stability of the particles during the granulation process.

[0108] Composition of volatile agent: low boiling point alcohols, including but not limited to at least one of polyethylene glycol, 1,3-propylene glycol, ethylene glycol and ethanol. The role of volatile agents is to form tiny pores during the granulation process, thereby reducing the bulk density. At the same time, they also help to adjust the fluidity of the slurry.

[0109] The content of the volatile agent is 2%wt-5%wt. This content range ensures that the volatile agent can be evenly distributed in the slurry while avoiding performance problems caused by too much or too little.

[0110] Thickener ingredients: at least one of sodium carboxymethyl cellulose, guar gum, xanthan gum, and polyacrylic acid. The main function of thickeners is to increase the viscosity of the glue so that it can better adhere to the surface of the particles. At the same time, they also help to improve the stability of the slurry.

[0111] The dosage of the thickener is 0.1-0.5%wt. This dosage range ensures that the thickener can form sufficient viscosity in the second glue to meet the needs of the granulation process.

[0112] The detailed definition of the ingredients and content of the glue ensures that the black granulated powder glue has the required adhesion, fluidity and stability. The selection and content range of these ingredients reflect the in-depth understanding and fine operation of the preparation process, providing a strong guarantee for the quality control of the final product.

[0113] S103, continuously stirring the black granulation powder slurry, and adding the black granulation powder glue dropwise into the black granulation powder slurry to obtain a second mixed slurry.

[0114] It should be noted that this step is to drop the prepared black granulation powder glue into the black granulation powder slurry that is being continuously stirred. Through continuous stirring, it can be ensured that the glue is evenly dispersed in the slurry to form a second mixed slurry. The key to this step is to control the dripping speed and stirring speed of the glue to avoid excessively high or low local concentrations.

[0115] In a specific implementation of this embodiment, step S103 describes in detail how to evenly add black granulation powder glue to black granulation powder slurry to obtain a second mixed slurry. This step is a key step in the granulation process and has an important impact on the performance and quality of the final product. The following is a detailed description of this step:

[0116] Equipment preparation: First, add the black granulation powder slurry into the high-pressure homogenizer. The high-pressure homogenizer is a commonly used dispersion equipment that can refine the particles and evenly disperse them in the slurry through high-speed shearing and impact.

[0117] Glue dripping: Then, add the black granulation powder glue droplets into the black granulation powder slurry through a peristaltic pump. A peristaltic pump is a pump that can accurately control the flow rate and is suitable for this scenario where glue needs to be added slowly and evenly.

[0118] Continuous stirring: While adding glue, the high-pressure homogenizer continuously stirs the slurry to ensure sufficient mixing between the glue and the slurry.

[0119] Dropping time: The dropping time is set to 3-4 hours. This time range ensures that the glue can be added to the slurry slowly and evenly, avoiding uneven performance caused by local concentration being too high or too low.

[0120] High-pressure homogenizer frequency: The frequency of the high-pressure homogenizer is set at 50-60Hz. This frequency range ensures that the equipment can provide sufficient shear and impact force to refine and evenly disperse the particles.

[0121] High pressure homogenizer pressure: The pressure is set to 600-700 Bar. Appropriate pressure helps to accelerate the particle refinement and dispersion process and improve the uniformity of the slurry.

[0122] Peristaltic pump speed: The speed of the peristaltic pump is set at 40-80r / min. This speed range ensures that the glue can be dripped into the slurry at a stable flow rate, avoiding uneven mixing caused by flow fluctuations.

[0123] After the above steps and parameter control, the second mixed slurry is finally obtained. This slurry has uniform particle distribution and stable performance, providing a solid foundation for subsequent granulation, drying and other steps.

[0124] S104, shearing and dispersing the second mixed slurry to obtain a high-viscosity slurry.

[0125] It should be noted that after the second mixed slurry is obtained, it needs to be subjected to shear dispersion treatment. The purpose of shear dispersion is to further refine the particles, improve the uniformity and stability of the slurry, and increase the viscosity of the slurry. The high viscosity slurry is conducive to the subsequent granulation process and can ensure the close bonding between the particles.

[0126] In a specific implementation of this embodiment, step S104 describes in detail how to use a high-speed shear disperser to shear and disperse the second mixed slurry, so that the low-boiling point volatile agent can be evenly dispersed in the slurry, so that the pores in the granulation balls after spray granulation are more fine and uniform, so as to obtain a high-viscosity slurry. This step is one of the key steps in the granulation process and has an important impact on the performance and quality of the final product. The following is a detailed description of this step:

[0127] Equipment preparation: First, pour the second mixed slurry into the container of the high-speed shear disperser. The high-speed shear disperser is a commonly used dispersion equipment that can strongly shear and impact the slurry through a high-speed rotating dispersion disk, thereby refining the particles and improving its dispersibility.

[0128] Shear dispersion: Next, start the high-speed shear disperser to rotate the dispersion disc at a certain speed. During the rotation process, the dispersion disc will produce strong shear and impact effects on the slurry, refining the particles and evenly dispersing them in the slurry.

[0129] Parameter control: In order to ensure the shear dispersion effect, the speed of the dispersion disk and the dispersion time need to be strictly controlled. In this embodiment, the speed of the dispersion disk is set to 3000-5000r / min, and the dispersion time is set to 5-10min. The selection of these parameters depends on the characteristics of the slurry and the required dispersion effect.

[0130] Dispersion disk speed: The speed directly affects the shear dispersion effect. Too low a speed may lead to insufficient particle refinement and poor dispersion effect; too high a speed may generate too much heat and cause the slurry to deteriorate. Therefore, choosing the right speed is crucial.

[0131] Dispersion time: The length of dispersion time also directly affects the dispersion effect of the slurry. If the time is too short, the particles may not be fully refined and the dispersion may be uneven; if the time is too long, energy and time may be wasted, and even unnecessary damage may be caused to the slurry. Therefore, the dispersion time needs to be strictly controlled.

[0132] Slurry viscosity: After shear dispersion, the viscosity of the slurry will change. In this embodiment, the viscosity of the high-viscosity slurry is set to 500-1000mPa∙s. This viscosity range ensures that the slurry has sufficient fluidity and stability, providing a solid foundation for subsequent steps (such as granulation, drying, etc.).

[0133] After the above steps and parameter control, a high viscosity slurry is finally obtained. This slurry has uniform particle distribution, stable performance and suitable viscosity, which provides good conditions for the subsequent granulation step.

[0134] S105, granulating the high-viscosity slurry to obtain black nano zirconium oxide granulated powder with low bulk density.

[0135] It should be noted that this is the last step in the preparation process. The high-viscosity slurry is fed into a granulator and converted into granules through an appropriate granulation process (such as spray drying, extrusion granulation, etc.). Due to the introduction and volatilization of the volatile agent in the previous step, tiny pores will be formed during the granulation process, thereby reducing the bulk density of the particles. The resulting low bulk density black nano zirconium oxide granulated powder not only has excellent physical properties, but also meets the market demand for light and thin products.

[0136] In a specific implementation of this embodiment, step S105 describes in detail how to use a centrifugal spray granulation dryer to granulate the high viscosity slurry to obtain low bulk density black nano zirconium oxide granulated powder. This step is the core link in the entire preparation process and is directly related to the quality and performance of the final product. The following is a detailed description of this step:

[0137] Equipment preparation: First, feed the high-viscosity slurry into the hopper of the centrifugal spray granulation dryer. The centrifugal spray granulation dryer is a commonly used granulation equipment that uses a high-speed rotating centrifugal disk to atomize the slurry into tiny droplets, which are then quickly dried and solidified in hot air to form granules.

[0138] Parameter setting: In order to ensure the granulation effect, it is necessary to set appropriate inlet air temperature, outlet temperature and atomization frequency. In this embodiment, the inlet air temperature is set to 200-220°C, the outlet temperature is set to 96-105°C, and the atomization frequency is set to 30-35Hz. The selection of these parameters depends on the characteristics of the slurry and the desired granulation effect.

[0139] Granulation process: Start the centrifugal spray granulation dryer, and the slurry is atomized into tiny droplets under the action of the centrifugal disk. These droplets are quickly dried and solidified in the hot air to form particles. At the same time, the size, shape and bulk density of the particles can be controlled by adjusting the inlet temperature, outlet temperature and atomization frequency.

[0140] Inlet air temperature: The inlet air temperature directly affects the drying speed and curing effect of the particles. Too high a temperature may cause the surface of the particles to solidify too quickly, and the internal moisture cannot be discharged in time, forming a hard shell; too low a temperature may prolong the drying time and reduce production efficiency. Therefore, it is very important to choose the right inlet air temperature.

[0141] Outlet Temperature: The outlet temperature reflects the temperature of the pellets as they leave the dryer. This temperature needs to be within a certain range to ensure that the pellets are completely dry and not overheated. Exit temperatures that are too high may cause the pellets to burn or discolor; exit temperatures that are too low may indicate inadequate drying.

[0142] Atomization frequency: Atomization frequency determines the number and size of droplets atomized into by the slurry. Too high a frequency may result in too small droplets, larger gaps between particles, and lower bulk density; too low a frequency may result in too large droplets and irregular particle shapes. Therefore, it is necessary to strictly control the atomization frequency to obtain the ideal particle shape and bulk density.

[0143] After the above steps and parameter control, low bulk density black nano zirconium oxide granulated powder was finally obtained. This product has uniform particle distribution, good dispersibility and stable performance, meeting the needs of subsequent applications.

[0144] It is understandable that after obtaining the granulated powder, it is only necessary to carry out pressing, debinding, sintering, finishing and other processes to produce black zirconium oxide products.

[0145] In order to prove the feasibility of the method provided by the present invention, a specific experimental example and a specific comparative example are described in detail below.

[0146] Experimental example:

[0147] (1) The amount of white yttrium-stabilized zirconia calcined powder is 95%wt, wherein the yttrium content is 2.5%mol, D10 is 0.070μm, D50 is 0.140μm, and D90 is 0.400μm. The amount of calcined black pigment powder is 5%wt, wherein the components used are iron, cobalt, nickel, manganese, titanium, and aluminum, D10 is 0.150μm, D50 is 0.420μm, and D90 is 0.80μm. The amount of dispersant is 0.5%wt. Deionized water is used, ball milling is performed for 2h, and the ball milling frequency is 50Hz to obtain a first mixed slurry with a solid content of 45%;

[0148] (2) The first mixed slurry is sanded for 8 rounds at a main sanding speed of 650 r / min to obtain a homogeneous slurry with a D10 of 0.07 μm, a D50 of 0.15 μm, and a D90 of 0.45 μm, which is a black granulation powder slurry;

[0149] (3) A first glue is prepared using a binder and a volatile agent, wherein the amount of the volatile agent is 3%wt, the amount of the binder is 3.5%wt, the stirring time is 2h, the frequency is 40Hz, and the pressure is 500Bar; a second glue with a concentration of 0.35% is prepared using a thickener and pure water, the amount is 45%wt, the stirring time is 7h, the frequency is 40Hz, and the pressure is 500Bar. The first glue and the second glue are mixed to obtain a uniform third glue, namely, black granulated powder glue, with a mixing time of 1.5h, a frequency of 50Hz, and a pressure of 600Bar;

[0150] (4) using a peristaltic pump to drop black granulation powder glue into the black granulation powder slurry for 4 hours, with an agitator frequency of 50 Hz, a pressure of 600 Bar, and a peristaltic pump speed of 60 r / min to obtain a second mixed slurry;

[0151] (5) using a high-speed shear disperser to disperse the second mixed slurry at a dispersing disk speed of 3000 r / min for 10 min to obtain a high-viscosity slurry with a viscosity of 800 mPa∙s;

[0152] (6) spraying and granulating the high viscosity slurry through a centrifugal spray dryer to obtain black nano zirconium oxide granulated powder with low bulk density;

[0153] (7) The low bulk density black nano zirconium oxide granulated powder is subjected to pressing, debinding, sintering, and finishing processes in sequence.

[0154] Comparative Example:

[0155] (1) The amount of white yttrium-stabilized zirconia calcined powder is 95%wt, wherein the yttrium content is 2.5%mol, D10 is 0.07μm, D50 is 0.140μm, and D90 is 0.400μm. The amount of calcined black pigment powder is 5%wt, wherein the components used are iron, cobalt, nickel, manganese, titanium, and aluminum, D10 is 0.150μm, D50 is 0.420μm, and D90 is 0.80μm. The amount of dispersant is 0.5%wt. Deionized water is used, ball milling is performed for 2h, and the ball milling frequency is 50hz to obtain a first mixed slurry with a solid content of 45%;

[0156] (2) The first mixed slurry is sanded for 8 rounds at a main sanding speed of 650 r / min to obtain a homogeneous slurry with a D10 of 0.07 μm, a D50 of 0.15 μm, and a D90 of 0.45 μm, which is a black granulation powder slurry;

[0157] (3) Glue a was prepared using a plasticizer and a binder, wherein the amount of the plasticizer was 0.5-1%wt, the amount of the binder was 3.5%wt, the stirring time was 2h, the frequency was 40HZ, and the pressure was 500Bar; a thickener glue b with a concentration of 0.35% was prepared, the amount was 45%wt, the stirring time was 7h, the frequency was 40HZ, and the pressure was 500Bar; glue a and glue b were mixed to obtain glue c, the mixing time was 1.5h, the frequency was 50HZ, and the pressure was 600Bar;

[0158] (4) Use a peristaltic pump to add glue c to the black granulation powder slurry for 4 hours, the stirrer frequency is 50 Hz, the pressure is 600 Bar, and the peristaltic pump speed is 60 r / min to obtain slurry D;

[0159] (5) spray granulating the slurry D by a centrifugal spray dryer to obtain black nano zirconium oxide granulated powder;

[0160] (6) The black nano zirconium oxide granulated powder is subjected to pressing, debinding, sintering, and finishing processes in sequence.

[0161] Comparison results:

[0162] The pelletized balls of the experimental example are as follows Figure 2 As shown, the crushing effect of the experimental example is as follows Figure 4 As shown, the finished product surface of the experimental example is Figure 6 shown.

[0163] The comparative example of granulated balls is as follows Figure 3 As shown, the crushing effect of the comparative example is as follows Figure 5 As shown, the surface of the finished product of the comparative example is as follows Figure 7 shown.

[0164] It can be seen that the method in the experimental example can produce black nano zirconium oxide granulated powder with low bulk density.

[0165] Although the terms such as volatile agent and adhesive are used more frequently in this application, the possibility of using other terms is not excluded. These terms are used only to more conveniently describe and explain the essence of the present invention; interpreting them as any additional restrictions is contrary to the spirit of the present invention.

[0166] The present invention provides a method for preparing a black nano-zirconia granulated powder with low bulk density, which marks an important progress in the relevant technical field. Specifically, the process cleverly introduces a volatile agent component into its formulation system. This design is intended to utilize the natural volatility characteristics of the volatile agent during the high-temperature granulation process to form a series of tiny pore structures inside the final product. This unique process mechanism enables the successful preparation of black nano-zirconia granulated powder with significantly low bulk density. The black zirconia product produced by the granulated powder prepared by this method has fewer pores, a mirror effect after polishing, and a high blackness L value of the product <3, a flexural strength of more than 1100Mpa, and saves about 50%-60% of the cost.

[0167] Compared with traditional preparation technology, the implementation of the present invention not only significantly reduces the amount of powder material required, saving about 40-50% of the powder, but also effectively responds to the current market's growing demand for lightweight and thin products, and achieves a substantial reduction in production costs by optimizing the material structure. In addition, the application of this innovative process has greatly enhanced the market competitiveness of the product and provided strong technical support for the transformation, upgrading and sustainable development of related industries. In summary, the present invention not only enriches the connotation of nano-zirconia material preparation technology, but also contributes important forces to meeting diversified market demands and promoting industrial upgrading.

[0168] Finally, it should be noted that although the above embodiments have been described in the specification and drawings of this application, this does not limit the scope of patent protection of this application. All technical solutions generated by replacing or modifying equivalent structures or equivalent processes based on the essential concept of this application using the contents recorded in the specification and drawings of this application, as well as directly or indirectly implementing the technical solutions of the above embodiments in other related technical fields, are included in the scope of patent protection of this application.

Claims

1. A method for preparing black nano zirconium oxide granulated powder with low bulk density, characterized in that: The method comprises: preparing a black granulation powder slurry; Prepare black granulation powder glue; the black granulation powder glue includes a volatile agent; The black granulation powder slurry is continuously stirred, and the black granulation powder glue is added dropwise into the black granulation powder slurry to obtain a second mixed slurry; Shearing and dispersing the second mixed slurry to obtain a high-viscosity slurry; The high-viscosity slurry is granulated to obtain black nano zirconium oxide granulated powder with low bulk density.

2. The method for preparing black nano zirconium oxide granulated powder with low bulk density according to claim 1, characterized in that: The steps of preparing the black granulated powder slurry include: Adding white yttrium-stabilized zirconia calcined powder and calcined black pigment powder into a drum ball mill, adding a certain amount of dispersant and pure water, and ball milling to obtain a first mixed slurry that is uniform and well dispersed; The first mixed slurry is sand-milled to obtain a homogeneous slurry, namely a black granulated powder slurry.

3. The method for preparing black nano zirconium oxide granulated powder with low bulk density according to claim 2, characterized in that: The white yttrium-stabilized zirconia calcined powder has an yttrium content of 2-3% mol; a particle size D10 of 0.05-0.08 μm, a D50 of 0.1-0.2 μm, and a D90 of 0.3-0.4 μm; The calcined black pigment powder has pigment components of several compounds of iron, cobalt, nickel, manganese, titanium, aluminum, vanadium and chromium; the particle size: D10 is 0.1-0.2 μm, D50 is 0.4-0.5 μm, and D90 is 0.7-0.8 μm.

4. The method for preparing black nano zirconium oxide granulated powder with low bulk density according to claim 2, characterized in that: The first mixed slurry is ball-milled for 2-4 hours; the size of the grinding medium is φ3mm, and the material is zirconium oxide; the ball-to-material weight ratio is 3:1; the amount of the white yttrium-stabilized zirconium oxide calcined powder is 95%-97%wt, the amount of the calcined black colorant powder is 3%-5%wt, the amount of the dispersant is 0.3%wt-0.6%wt, the slurry solid content is 40%-50%, and the drum ball mill frequency is 50-80Hz; The number of sand milling rounds is 6-8; the grinding medium size is φ0.3-0.4 mm, and the material is zirconium oxide; the main engine speed of the sand mill is 600-800 r / min; the particle size of the black granulation powder slurry is D50<0.15, D90<0.5 μm.

5. The method for preparing black nano zirconium oxide granulated powder with low bulk density according to claim 1, characterized in that: The steps of preparing black granulation powder glue include: Adding a binder and a volatile agent into a stirrer for mixing to obtain a first glue; Adding thickener and pure water into a stirrer and mixing them to obtain a second glue; The first glue and the second glue are added into a stirrer for mixing to obtain a uniform third glue, namely, black granulated powder glue.

6. The method for preparing black nano zirconium oxide granulated powder with low bulk density according to claim 5, characterized in that: When mixing the binder and the volatile agent, the frequency of the stirrer is 40-50 Hz, the pressure is 500-600 Bar, and the stirring time is 2-4 hours; When mixing the thickener and the pure water, the frequency of the stirrer is 40-50 Hz, the pressure is 500-600 Bar, and the stirring time is 6-8 hours; When mixing the first glue and the second glue, the frequency of the stirrer is 40-50 Hz, the pressure is 600-700 Bar, and the stirring time is 1-2 hours.

7. The method for preparing black nano zirconium oxide granulated powder with low bulk density according to claim 5, characterized in that: The binder is at least one of water-based polyacrylic acid, polyvinyl alcohol and polyethylene glycol, with a content of 2%wt-4%wt; the volatile agent is low-boiling alcohol, with a content of 2%wt-5%wt; The thickener is at least one of sodium carboxymethyl cellulose, guar gum, xanthan gum and polyacrylic acid, and the amount used is 0.1-0.5%wt.

8. The method for preparing black nano zirconium oxide granulated powder with low bulk density according to claim 1, characterized in that: The step of continuously stirring the black granulation powder slurry and adding the black granulation powder glue droplets into the black granulation powder slurry to obtain the second mixed slurry is: The black granulation powder slurry is added into a high-pressure homogenizer and stirred continuously, and the black granulation powder glue is added dropwise into the black granulation powder slurry through a peristaltic pump to obtain a second mixed slurry; The dropping time is 3-4 hours, the frequency of the high-pressure homogenizer is 50-60 Hz, the pressure is 600-700 Bar, and the speed of the peristaltic pump is 40-80 r / min.

9. The method for preparing black nano zirconium oxide granulated powder with low bulk density according to claim 1, characterized in that: The step of shearing and dispersing the second mixed slurry to obtain a high-viscosity slurry is: Using a high-speed shear disperser to shear and disperse the second mixed slurry to obtain a high-viscosity slurry; The rotation speed of the dispersion disk is 3000-5000 r / min, the dispersion time is 5-10 min, and the viscosity of the high-viscosity slurry is 500-1000 mPa∙s.

10. The method for preparing black nano zirconium oxide granulated powder with low bulk density according to claim 1, characterized in that: The step of granulating the high viscosity slurry to obtain low bulk density black nano zirconium oxide granulated powder is: The high-viscosity slurry is granulated using a centrifugal spray granulation dryer to obtain low bulk density black nano zirconium oxide granulated powder; Among them, the inlet air temperature is adjusted to 200-220℃, the outlet temperature is 96-105℃, and the atomization frequency is 30-35Hz.

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