A method for manufacturing ceramic hollow microspheres with high pressure resistance

Abstract

The application discloses a manufacturing method of ceramic hollow microsphere blank with high pressure strength, which comprises the following steps: mixing ceramic powder and glass powder in proportion; adding water, dispersant and adhesive, and ball-milling and crushing the mixture to be uniformly mixed into flowable slurry; using a spray drying process to manufacture ceramic hollow microsphere blank; and placing the hollow microsphere blank into a heating rotary furnace, discharging organic matters, melting glass components in the hollow microsphere blank, filling pores of the shell of the ceramic hollow microsphere blank, and densifying the shell of the ceramic hollow microsphere blank to improve the compression resistance of the ceramic hollow microsphere blank, and the compression strength of the ceramic hollow microsphere blank is greater than or equal to 80Mpa. The method has the advantages that glass is added into the ceramic powder, a spray drying process is used to manufacture ceramic hollow microsphere blank, and a two-step method of melting the glass components of the shell of the ceramic hollow microsphere by using a heating rotary furnace is used, so that the shell of the ceramic hollow microsphere is densified, and the mechanical compression resistance of the product is greatly improved.

Description

Technical Field

[0001] This invention relates to the field of ceramic preparation technology, and in particular to a method for manufacturing high-pressure resistant hollow ceramic microspheres. Background Technology

[0002] Ceramic and glass-ceramic hollow microspheres are a new type of high-tech inorganic material that has been widely used in various industries such as industry, agriculture, medicine, science and technology, and military.

[0003] Glass-ceramic hollow microspheres have been mass-produced in my country, but due to material limitations, their mechanical strength is low and they cannot be used in applications requiring pressure resistance and strength ≥100MPa. Therefore, high pressure-resistant ceramic hollow microspheres are expected to be developed.

[0004] However, my country is still unable to mass-produce ceramic hollow microspheres with a pressure resistance of >100MPa. The ceramic hollow microspheres currently produced in China are mainly composed of kaolin, also known as alumina. They are made using traditional spray drying technology, and their outer shell is porous, resulting in poor mechanical strength and making them unsuitable for large-scale application.

[0005] To address the problem of poor mechanical strength in hollow ceramic microspheres, some researchers in China have combined traditional spray drying with plasma heating spraying. This two-step method involves using plasma heating equipment to instantly melt the outer shell of the hollow ceramic microsphere blank at temperatures exceeding 8000℃, followed by rapid cooling via spraying. This process preserves the hollow structure while melting the outer shell into a dense and hard ceramic crystal, significantly improving its mechanical strength. Details are provided in Chinese invention patents CN121292994.A and CN2010105785753. However, this type of ultra-high temperature plasma heating spraying equipment is expensive, consumes a lot of electricity, and has a relatively low production capacity. For example, the smallest laboratory model, SX-60, costs 260,000 yuan, has a power consumption of 60 kilowatts, and a production capacity of less than 5 kg per hour. Large-scale industrial production would significantly increase the cost of the product, hindering its widespread application. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to address the shortcomings of the existing technology, namely the low compressive strength of ceramic hollow microspheres currently on the market and the defects of the plasma ultra-high temperature heating melting spray method. The present invention provides a method for manufacturing ceramic hollow microsphere blanks with high pressure resistance. To solve the above technical problem, the present invention adopts the following technical solution.

[0007] A method for manufacturing high-pressure resistant hollow ceramic microspheres, comprising: Step 1: Preparation of ceramic hollow microsphere preforms. Ceramic powder and glass powder are mixed in a weight ratio of 70~80:30~20 to obtain a mixed main material. The mixed main material, water, dispersant and binder are mixed in a weight ratio of 1000:400~600:0.5~2:3~8. Then, the mixture is ball-milled and pulverized into a fluid slurry. The ceramic hollow microsphere preforms are then produced by spray drying. Step 2: Preparation of hollow ceramic microspheres. The hollow microspheres are placed in a rotary furnace at a temperature of 800~1100 degrees Celsius for 1~3 hours to remove organic matter and melt the glass components. The pores of the hollow ceramic microsphere shell are filled to densify the shell and improve the compressive strength of the hollow ceramic microspheres, which is ≥80 MPa.

[0008] A preferred embodiment is that the glass composition in step 1 includes silicon oxide, boron oxide, aluminum oxide, zinc oxide, phosphorus oxide, bismuth oxide, and calcium oxide.

[0009] The glass in step 1 is composed of one or more oxides of boron, silicon, and aluminum, bismuth oxide, phosphorus pentoxide, zinc oxide, and calcium oxide.

[0010] A preferred embodiment is that step 1 includes the following steps: Step 101: Glass powder preparation. Silicon oxide, boron oxide, aluminum oxide, zinc oxide, phosphorus oxide, bismuth oxide, and calcium oxide from the glass composition, along with water and a dispersant, are mixed at a weight ratio of 100:100:0.5~2. The mixture is then pulverized using a ball mill to prepare a fluid slurry. The particle size of the pulverized slurry is [missing information]. Dry the slurry and pass it through a 35-meter channel. 65-mesh sieve, corundum crucible in tongs, at 1000 Insulation at 1200 degrees Celsius for 1.5 seconds Melt for 2.5 hours, remove and quench in cold water until loose, remove and dry, then dry-mill using a ball mill to a particle size of [size missing]. ≈3~5 m glass powder is ready for use; Step 102: Slurry preparation. Mix the ceramic powder with the glass powder prepared in step 101, and obtain the main mixed material according to the ratio of ceramic powder to glass powder (80%~70%) to (20%~30%). Take the main mixed material, water, dispersant and binder and mix them in a weight ratio of 1000:400~600:0.5~2:3~8. Mix and pulverize the mixture into a fluid slurry using a ball mill at 180~230 rpm. Step 103: Preparation of hollow ceramic microsphere preforms. The ceramic powder and glass powder mixture from step 102 is spray-dried to form hollow ceramic microsphere preforms with an outer diameter between 10 and 30 micrometers. In step 2, the prepared ceramic hollow microsphere blank is calcined in a rotary furnace at a temperature of 800℃~1000℃ for 1.5~2.5 hours to completely remove the organic matter contained therein and soften and melt the glass components, filling the micropores of the ceramic hollow microsphere blank shell and making it denser.

[0011] A preferred embodiment is that the glass composition includes: boron oxide, silicon oxide, aluminum oxide, zinc oxide, calcium oxide, bismuth oxide, and phosphorus oxide.

[0012] The method for manufacturing high-pressure resistant ceramic hollow microspheres provided by this invention has at least the following beneficial effects: A two-step method is used, in which glass is added to ceramic powder, a ceramic hollow microsphere blank is first manufactured using a spray drying process, and then the glass component of the ceramic hollow microsphere shell is melted using a heated rotary furnace. This process densifies the outer shell of the ceramic hollow microspheres, greatly improving the mechanical compressive strength of the product. The greatest feature of this invention is its simple process, low equipment cost, energy saving, and large production capacity, which is conducive to large-scale industrial production of low-cost products and promotes widespread application.

[0013] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of the present invention more apparent and understandable, preferred embodiments are described in detail below. Detailed Implementation

[0014] To illustrate the ideas and objectives of this application, the following will provide further explanation of this application in conjunction with specific embodiments.

[0015] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs; the terminology used herein in the specification of the application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application; the specification and claims of this application and the foregoing terms “comprising” and “having” and any variations thereof are intended to cover non-exclusive inclusion. The terms “first,” “second,” “left,” “right,” etc., in the specification and claims of this application are used to distinguish different objects, not to describe a particular order.

[0016] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0017] First embodiment, A method for manufacturing high-pressure resistant hollow ceramic microspheres, comprising: Step 1: First, prepare ceramic hollow microsphere preforms. Mix ceramic powder and glass powder in a weight ratio of 70~80:30~20 to obtain a mixed main material. Take the mixed main material, water, dispersant and binder and mix them in a weight ratio of 1000:400~600:0.5~2:3~8. Then, ball mill and mix them evenly to form a fluid slurry. Use spray drying process to make ceramic hollow microsphere preforms. Step 2: Prepare hollow ceramic microspheres. Place the hollow micro-green body in a rotary furnace at a temperature of 800~1100 degrees Celsius for 1~3 hours to remove organic matter and melt the glass components. Fill the pores of the outer shell of the hollow ceramic microsphere green body to densify the outer shell of the hollow ceramic microsphere green body, thereby improving the compressive strength of the hollow ceramic microsphere green body, with a compressive strength ≥80Mpa.

[0018] Second embodiment, The difference between this embodiment and the first embodiment is that the glass composition in step 1 includes silicon oxide, boron oxide, aluminum oxide, zinc oxide, phosphorus oxide, bismuth oxide and calcium oxide.

[0019] Third embodiment, The difference between this embodiment and the first embodiment is that the glass in step 1 is composed of one or more oxides of boron, silicon, and aluminum, bismuth oxide, phosphorus pentoxide, zinc oxide, and calcium oxide.

[0020] Fourth embodiment, The difference between this embodiment and the first embodiment is: a method for manufacturing high-pressure resistant ceramic hollow microspheres.

[0021] Step 1 includes the following steps: Step 101: Glass powder preparation. The oxides, water, and dispersant in the glass are mixed at a weight ratio of 100:100:0.5~2, and then pulverized using a ball mill to prepare a fluid slurry. The particle size of the pulverized slurry is [missing information]. Dry the slurry and pass it through a 35-meter channel. 65-mesh sieve, corundum crucible, at 1000 Insulation at 1300 degrees Celsius for 1.5 seconds Melt for 2.5 hours, remove and quench in cold water until loose, remove and dry, then dry-mill using a ball mill to a particle size of [size missing]. Glass powder with a particle size of approximately 3-5 micrometers is available for use. Step 102: Slurry preparation. Mix the ceramic powder with the glass powder prepared in step 101, and obtain the main mixed material according to the ratio of ceramic powder to glass powder (80%~70%) to (20%~30%). Take the main mixed material, water, dispersant and binder and mix them in a weight ratio of 1000:400~600:0.5~2:3~8. Mix and pulverize the mixture into a fluid slurry using a ball mill at 180~230 rpm. Step 103: Preparation of hollow ceramic microsphere preforms. The ceramic powder and glass powder mixture from step 102 is spray-dried to form hollow ceramic microsphere preforms with an outer diameter between 10 and 30 micrometers. In step 2, the prepared ceramic hollow microsphere blank is calcined in a rotary furnace at a temperature of 800℃~1000℃ for 1.5~2.5 hours to completely remove the organic matter contained therein and soften and melt the glass components, filling the micropores of the ceramic hollow microsphere blank shell and making it denser.

[0022] Fifth embodiment, A method for manufacturing high-pressure resistant hollow ceramic microspheres, comprising: Step 1: First, prepare the ceramic hollow microsphere preform. Mix ceramic powder and glass powder at a weight ratio of 70:30 to obtain the mixed main material. Take the mixed main material, water, dispersant and binder and mix them at a weight ratio of 1000:500:2:4. Then, ball mill and pulverize the mixture into a fluid slurry. Use spray drying process to make the ceramic hollow microsphere preform. Step 2: Prepare hollow ceramic microspheres. Place the hollow microsphere blank in a rotary furnace at 1000 degrees Celsius for 2 hours to remove organic matter and melt the glass components. Fill the pores of the outer shell of the hollow ceramic microsphere blank to densify the outer shell and improve the compressive strength of the hollow ceramic microsphere blank, which is ≥80 MPa.

[0023] Sixth embodiment, The difference between this embodiment and the first embodiment is: Step 1 includes the following steps: Step 101: Glass powder preparation. Silicon oxide, boron oxide, aluminum oxide, zinc oxide, phosphorus oxide, bismuth oxide, and calcium oxide from the glass composition, along with water and a dispersant, are mixed in a weight ratio of 100:100:1. The mixture is then pulverized using a ball mill to prepare a fluid slurry. The particle size of the pulverized slurry is [missing information]. The slurry was dried, passed through a 60-mesh sieve, placed in a corundum crucible, and melted at 1100 degrees Celsius for 2 hours. Afterward, it was quenched in cold water until it became porous, then dried and dry-milled using a ball mill until the particle size was [size missing]. Prepare glass powder with a particle size of approximately 4 micrometers. Step 102: Slurry preparation. Mix the ceramic powder with the glass powder prepared in step 101, and obtain the main mixed material with a ceramic powder to glass powder ratio of 80% to 20%. Take the main mixed material, water, dispersant and binder and mix them in a weight ratio of 1000:600:2:6. Mix and pulverize them into a fluid slurry using a ball mill at 200 rpm. Step 103: Preparation of hollow ceramic microsphere preforms. The ceramic powder and glass powder mixture from step 102 is spray-dried to form hollow ceramic microsphere preforms with an outer diameter between 10 and 30 micrometers. In step 2, the prepared ceramic hollow microsphere blank is calcined in a rotary furnace at a temperature of 800℃~1000℃ for 2.5 hours to completely remove the organic matter contained therein and soften and melt the glass components, filling the micropores of the ceramic hollow microsphere blank shell and making it denser.

[0024] Seventh embodiment, (1) First, weigh the following raw materials according to their weight percentages to obtain glass powder: 30%, 20%, 20%, 10%, 10%, 5%, 5%.

[0025] Take 1000 grams of the above-mentioned glass powder, add 500 grams of water, 1 gram of dispersant, and 5 grams of binder, and grind it in a planetary ball mill at 200 rpm for 4 hours to obtain... The slurry is made of micrometers in size; the slurry is removed, dried, and passed through a 40-mesh sieve; then it is placed in a corundum crucible and heated to melt in a rotary furnace at 1200 degrees Celsius for 2 hours. It is then removed, quenched in cold water to form a loose texture, and ground into 3-5 micrometer glass powder using a high-speed ball mill for later use. The binder is gum arabic.

[0026] (2) Mix 1 kg of alumina powder and the above glass powder in a ratio of 70% and 30%, add 500 g of water, 1 g of dispersant and 5 g of binder, mix with a planetary ball mill at 200 rpm and pulverize for 4 hours to make a slurry with good fluidity.

[0027] (3) The above slurry is spray-dried using a spray drying tower with the following parameters: With an air pressure of 0.3~0.4MPa, an input flow rate of 10mL per minute, a nozzle size of 1~1.5mm, and an outlet temperature of 95℃~100℃, a hollow spherical blank with an outer diameter of 10~20 micrometers can be obtained.

[0028] (4) The hollow sphere blank is heated in a rotary furnace at 800℃~1000℃ for 1 hour to remove the organic matter and soften or even melt the glass powder to fill the pores of the ceramic hollow microsphere shell and make it dense. The hydrostatic pressure test shows that its compressive strength is ≥100MPa.

[0029] Eighth embodiment, (1) Weigh 1 kg of industrial pure mullite ceramic powder (D50=3 microns) and the above glass powder in a ratio of 65% and 35%, respectively. Add 500 g of water, 1 g of dispersant, and 5 g of alabaster gum binder. Grind with a planetary mill at 200 rpm and mix for 4 hours to make a slurry with good flowability.

[0030] Spray drying and granulation are performed using a spray drying tower with the following parameters: Air pressure 0.3~0.4MPa, flow rate nozzle: 30ml per minute, nozzle diameter 2mm, outlet temperature 95~100℃. Because the slurry input flow rate increases, the nozzle inner hole also increases, so the outer diameter of the hollow spheres obtained by spray drying increases to 20~30 micrometers.

[0031] (2) The obtained ceramic hollow sphere blank is heat-treated in a rotary furnace at 800℃~1000℃ to melt the glass in the blank, remove organic matter and water, and melt the glass to fill the pores of the hollow sphere blank, making it dense and increasing its mechanical compressive strength.

[0032] (3) The main technical parameters of the ceramic hollow microspheres prepared by the method of the present invention are as follows: Outer diameter: 5 micrometers to 50 micrometers, true density: 0.3 to 0.6 g / cm³, compressive strength: ≥100MPa, sphericity: >95%. Among them, ceramic hollow microspheres can be used as additives in oilfield drilling fluids, cementing cement, engineering plastics, artificial marble, thermal insulation materials, marine solid materials and other fields to improve various properties.

[0033] Mullite ceramic hollow spheres, because their dielectric constant is <3, can be used in 5G communication PCBs to reduce transmission loss of microwave signals.

[0034] The above are specific embodiments of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications are also considered to be within the scope of protection of the present invention.

Claims

1. A method for manufacturing high-pressure resistant hollow ceramic microspheres, characterized in that, include: Step 1: Preparation of ceramic hollow microsphere preforms. Ceramic powder and glass powder are mixed in a weight ratio of 70~80:30~20 to obtain a mixed main material. The mixed main material, water, dispersant and binder are mixed in a weight ratio of 1000:400~600:0.5~2:3~8. Then, the mixture is ball-milled and pulverized into a fluid slurry. The ceramic hollow microsphere preforms are then produced by spray drying. Step 2: Preparation of hollow ceramic microspheres. The hollow microspheres are placed in a rotary furnace at a temperature of 800~1100 degrees Celsius for 1~3 hours to remove organic matter and melt the glass components. The pores of the hollow ceramic microsphere shell are filled to densify the shell and improve the compressive strength of the hollow ceramic microspheres, which is ≥80 MPa.

2. The method for manufacturing high-pressure resistant hollow ceramic microspheres according to claim 1, characterized in that, The glass composition in step 1 includes silicon oxide, boron oxide, aluminum oxide, zinc oxide, phosphorus oxide, bismuth oxide, and calcium oxide.

3. The method for manufacturing high-pressure resistant hollow ceramic microspheres according to claim 1, characterized in that, The glass in step 1 is composed of one or more oxides of boron, silicon, and aluminum, bismuth oxide, phosphorus pentoxide, zinc oxide, and calcium oxide.

4. The method for manufacturing high-pressure resistant hollow ceramic microspheres according to claim 2, characterized in that, Step 1 includes the following steps: Step 101: Glass powder preparation. Silicon oxide, boron oxide, aluminum oxide, zinc oxide, phosphorus oxide, bismuth oxide, and calcium oxide from the glass composition, along with water and a dispersant, are mixed at a weight ratio of 100:100:0.5~2. The mixture is then pulverized using a ball mill to prepare a fluid slurry. The particle size of the pulverized slurry is [missing information]. Micrometers, dry the slurry, pass it through a 35-65 mesh sieve, place it in an alumina crucible tongs, and heat it at 1000... Insulation at 1200 degrees Celsius for 1.5 seconds Melt for 2.5 hours, remove and quench in cold water until loose, remove and dry, then dry-mill using a ball mill to a particle size of [size missing]. Glass powder with a particle size of approximately 3-5 micrometers is available for use. Step 102: Slurry preparation. Mix the ceramic powder with the glass powder prepared in step 101, and obtain the main mixed material according to the ratio of ceramic powder to glass powder (80%~70%) to (20%~30%). Take the main mixed material, water, dispersant and binder and mix them in a weight ratio of 1000:400~600:0.5~2:3~8. Mix and pulverize the mixture into a fluid slurry using a ball mill at 180~230 rpm. Step 103: Preparation of hollow ceramic microsphere preforms. The ceramic powder and glass powder mixture from step 102 is spray-dried to form hollow ceramic microsphere preforms with an outer diameter between 10 and 30 micrometers. In step 2, the prepared ceramic hollow microsphere blank is calcined in a rotary furnace at a temperature of 800℃~1000℃ for 1.5~2.5 hours to completely remove the organic matter contained therein and soften and melt the glass components, filling the micropores of the ceramic hollow microsphere blank shell and making it denser.

5. The method for manufacturing high-pressure resistant hollow ceramic microspheres according to any one of claims 4, characterized in that, The glass composition includes: boron oxide, silicon oxide, aluminum oxide, zinc oxide, calcium oxide, bismuth oxide, and phosphorus oxide.