A method for preparing high-quality hollow glass microspheres with high mass ratio based on micro-porous glass powder

Abstract

This invention discloses a method for preparing high-performance hollow glass microspheres based on microporous glass powder. The method involves uniformly mixing mineral powders containing silicon, sodium, calcium, magnesium, boron, aluminum, phosphorus, or zinc, inorganic salts, or oxides, and melting them in a frit furnace at 1150–1370°C to form molten glass. Gas is injected into the molten glass through a porous distributor and stirred. Then, a rapid cooling process is used to obtain microporous glass blocks / sheets with a bubble diameter <1 μm and a bubble volume percentage of 9.5–15.2%. These microporous glass powders are then crushed, ground, and graded to obtain microporous glass powder with a particle size distribution range <1.1, a maximum particle size ≤90 μm, and a microporous bubble volume percentage of 1.2–3.4%. Finally, a high-temperature spheroidizing furnace is used to produce hollow glass microspheres with a mass percentage >80%. This method achieves the preparation of high-performance, low-cost hollow glass microspheres, thus solving the technical problem of low hollowing ratio caused by the limited total amount of gas that can be released during the high-temperature hollowing process of glass powder.

Description

Technical Field

[0001] This invention belongs to the field of new material technology of hollow glass microspheres (microbeads), specifically relating to a method for preparing high-quality hollow glass microspheres using a solid-phase powder method. Background Technology

[0002] Hollow glass microspheres, as a high-performance hollow, micron-sized spherical powder lightweight functional filler, possess synergistic properties of "low density and high strength," making them an essential material in many high-end fields. In aerospace, they are a core component of satellite radomes and rocket engine nozzle heat insulation layers, increasing structural weight reduction by 20%-30% while maintaining excellent thermal shock resistance and electromagnetic permeability. In deep-sea engineering, buoyancy materials based on hollow glass microspheres can withstand the extreme pressure of 10,000 meters deep, providing stable buoyancy support for deep-sea exploration equipment. In the new energy vehicle sector, they are used to prepare lightweight battery pack shells and thermal insulation buffer materials, contributing to vehicle weight reduction while improving battery system safety and lifespan. Furthermore, in civilian applications such as well cement slurry for oil and gas extraction, building insulation coatings, and high-performance composite materials, hollow glass microspheres, with their low thermal conductivity, low dielectric constant, and high filling capacity, are driving technological upgrades in these industries.

[0003] Since 3M in the United States achieved industrial production in the 1950s, the global hollow glass microsphere industry has formed three mature preparation routes, with significant differences in technical characteristics and product performance among the various processes. The soft chemical method prepares microsphere precursors containing foamable components through a sol-gel reaction, followed by high-temperature calcination to form a hollow structure. This process boasts high raw material utilization, achieving a hollow ratio of over 80%, and relatively low production costs. However, the resulting glass network structure lacks density, with compressive strength at the same true density only 60%-70% of that of solid-phase methods. Furthermore, its chemical stability is poor, making it difficult to meet the stringent requirements of high-end fields such as aerospace. The liquid-phase atomization method atomizes glass melt containing a foaming agent into droplets, utilizing the gas generated by the decomposition of the foaming agent within the droplets to drive their expansion into spheres. This process boasts high production efficiency, making it suitable for large-scale mass production. The hollow component ratio of the product can be consistently maintained at around 75%. However, the melt atomization process struggles to precisely control droplet size and foaming agent distribution, resulting in a wide particle size distribution and significant strength fluctuations. Furthermore, the high energy consumption of the high-temperature melt processing limits its application in high-end precision fields. Solid-phase powder method: Using glass powder as raw material, the glass powder is softened at high temperatures. The release of gases from the physical dissolution or chemical bonding within the powder drives the particles to expand into spheres. Having undergone a complete glass melting and network structure reconstruction process, the hollow glass microspheres prepared by this process exhibit superior chemical stability and mechanical strength. Their compressive strength at the same true density is more than 40% higher than that of products prepared using the softening chemical method, making it the preferred material for high-end fields such as aerospace and deep-sea engineering.

[0004] Despite the significant performance advantages of hollow glass microspheres prepared by solid-state powder method, the process faces a key bottleneck: difficulty in increasing the hollow ratio. This is due to the inherent characteristics of the foaming mechanism. The gases that can be released from the glass powder mainly originate from the decomposition of raw material impurities (such as carbonates and sulfates) or the small amount of gas dissolved during glass melting. The total amount is very limited, and the gas release during high-temperature foaming is insufficient to support the full expansion of the glass particles. This results in a hollow ratio in the final product generally below 65%, with some low-true-density products even having a hollow ratio of less than 50%. This low hollow ratio not only limits the product's lightweight effect but also increases the material usage and cost in downstream applications. Therefore, without reducing product strength and chemical stability, overcoming the limitation of glass powder gas release and increasing the hollow spheroidization rate during high-temperature foaming has become the core direction for optimizing the solid-state powder method and a key technical challenge for upgrading the high-end hollow glass microsphere industry. Summary of the Invention

[0005] The purpose of this invention is to address the technical bottleneck of low hollow glass microsphere mass ratio in existing solid-phase powder preparation methods, and to provide a method for preparing high-quality hollow glass microspheres based on microporous glass powder. By using a porous distributor to introduce gas, the content and distribution of physical and chemical foaming agents in the glass powder can be controlled. The final product not only has a hollow glass microsphere mass ratio of >80%, but also low density and high compressive strength, thereby achieving the preparation of high-performance, low-cost hollow glass microspheres.

[0006] To achieve the above-mentioned objectives of this invention, a method for preparing high-quality hollow glass microspheres based on microporous glass powder is implemented using the following process steps:

[0007] S1, Raw material mixing and melting

[0008] Mineral powders, inorganic salts, or oxides containing silicon, sodium, calcium, magnesium, boron, aluminum, phosphorus, or zinc are mixed to form a homogeneous glass batch, including: quartz sand, borax, feldspar, calcium carbonate, calcium chloride, sodium carbonate, sodium chloride, magnesium carbonate, magnesium oxide, mirabilite, sodium phosphate, sodium dihydrogen phosphate, zinc phosphate, zinc oxide, aluminum oxide, etc. When the total mass of the glass batch components is calculated as 100%, the content of each component is 58.0~79.0% SiO2, 4.7~11.2% Na2O, 5.0~13.0% CaO, 0.3~1.8% MgO, 3.0~11.0% B2O3, 0~5.0% Al2O3, 1.0~2.5% P2O5, 0.5~1.6% ZnO, with the balance being 0~4.0%. The glass batch is then melted in a frit furnace at 1150~1370℃ to form molten glass.

[0009] S2, Gas injection - stirring and shearing - cooling and fixing

[0010] Gas is injected into the molten glass prepared in step S1 using a porous distributor, and stirring is employed to break up the bubbles using the shear force of the stirring, thus promoting a more uniform distribution of bubbles in the molten glass. The molten glass containing the bubbles is then rapidly cooled by a quenching method to complete the bubble fixation process, resulting in microporous glass blocks / sheets with bubble diameters <1μm and a bubble volume ratio of 9.5~15.2%. The quenching method refers to one of water quenching, cooling plate cooling, or rolling mill cooling, to quickly fix the morphology and distribution of bubbles in the molten glass.

[0011] S3, Grinding-Grading

[0012] The microporous glass blocks / sheets prepared in step S2 are crushed, ground, and graded to obtain microporous glass powder with a particle size distribution range of <1.1, a maximum particle size of ≤90μm, and a microporous bubble volume ratio of 1.2~3.4%.

[0013] S4, High-temperature spheroidization

[0014] The microporous glass powder obtained in step S3 is passed through a high-temperature spheroidizing furnace at 950~1050℃ to complete the hollow spheroidization process of the microporous glass powder, and a hollow glass microsphere product with a mass ratio of >80% is obtained.

[0015] To meet market demand for high compressive strength hollow glass microspheres, in step S1, when the total mass of the glass batch components is calculated as 100%, the content of each component is 64.0~73.0% SiO2, 5.5~7.9% Na2O, 8.0~11.0% CaO, 0.6~0.9% MgO, 4.5~7.5% B2O3, 2.0~5.0% Al2O3, 1.6~2.3% P2O5, 0.8~1.3% ZnO, 0.25~0.55% SO3, with the balance being 0~0.5%. At this point, through adjustment, in step S2, microporous glass blocks / sheets with an average bubble diameter of 0.51~0.65μm and a bubble volume ratio of 9.7~15.0% are obtained; in step S3, the microporous glass powder obtained through crushing, grinding, and grading has a maximum particle size of <70μm; and in step S4, the density of the hollow glass microspheres prepared is 0.50~0.65g / cm³. 3 Its compressive strength is 130~185MPa.

[0016] To meet market demand for low-density hollow glass microspheres, in step S1, when the total mass of the glass batch components is calculated as 100%, the content of each component is 75.0~79.0% SiO2, 7.5~10.5% Na2O, 5.0~7.0% CaO, 0.3~0.5% MgO, 3.0~6.5% B2O3, 1.0~1.5% P2O5, 0.7~1.2% ZnO, 1.5~2.8% SO3, with the balance being 0~0.5%. At this point, through adjustment, step S2 produces microporous glass blocks / sheets with an average bubble diameter of 0.21~0.31 μm and a bubble volume percentage of 13.5~15.5%. In step S3, the maximum particle size of the microporous glass powder obtained through crushing, grinding, and grading is <85 μm. The density of the hollow glass microspheres prepared in step S4 is 0.11~0.21 g / cm³. 3 The compressive strength is 5.0~12.0 MPa. Furthermore, by adjusting the parameters, in step S2, microporous glass blocks / sheets with an average bubble diameter of 0.68~0.78 μm and a bubble volume ratio of 12.1~13.5% can be obtained; in step S3, the maximum particle size of the microporous glass powder obtained through crushing, grinding, and grading is <77 μm; and in step S4, the density of the hollow glass microspheres prepared is 0.19~0.26 g / cm³. 3 The compressive strength is 11.0~18.0MPa.

[0017] Preferably, in step S2, the porous distributor refers to an array of microporous nozzles / tubes that can withstand high temperatures of 1370°C, or a porous special ceramic / metal with interconnected micropores inside.

[0018] Preferably, in step S3, the microporous glass blocks / sheets are coarsely crushed by a jaw crusher or a double roll crusher, then finely ground by one or a combination of a ball mill, air jet mill, stirred mill, and rod mill, and finally separated into microporous glass powder of the required particle size and span by physical sieving, air classification, or wet classification.

[0019] Further, in step S3, glass powder with an average particle size D50 of 100~150μm is obtained by coarse crushing with a roller crusher, and coarse grinding with a ball mill, stirred mill or rod mill; then fine grinding is carried out with a fluidized bed air jet mill; finally, microporous glass powder with the required particle size and span is sorted by a multi-stage air jet classification system.

[0020] In step S2, the specific composition and proportion of the injected gas are not limited, but a neutral or oxidizing atmosphere is preferred. This type of atmosphere has a dual optimizing effect: firstly, it can inhibit the thermal decomposition kinetics of some foaming agents (such as certain carbonates, nitrates, and sulfates), thereby effectively slowing down their decomposition rate and achieving better control over the foaming agent decomposition process; secondly, it can significantly enhance the solubility and retention of sulfur-containing gases (such as SO3 and SO2) in the molten glass, mainly due to the oxidizing conditions promoting the formation of stable sulfate ions (SO4²⁻) from sulfur. - The form is incorporated into the glass network structure.

[0021] The above-mentioned technical solution of the present invention realizes the preparation of hollow glass microspheres with a high hollow ratio by solid-phase powder method from the aspects of glass powder structure, chemical and physical foaming agents, and particle size distribution control.

[0022] The method for preparing high-quality hollow glass microspheres based on microporous glass powder of the present invention, after adopting the above technical solution, has the following beneficial effects:

[0023] (1) Gas is uniformly injected through a porous distributor (microporous structure) and combined with stirring to avoid the generation of abnormally large bubbles and reduce the overflow of small bubbles from the molten glass, thus avoiding excessive local gas accumulation and the formation of super-large bubbles; the stirring shear force breaks the initial bubbles down to the micron level, eliminating the glass block structure defects caused by large bubbles from the source, and achieving control over the size and volume of bubbles.

[0024] (2) By using the microstructure design of the porous distributor in conjunction with stirring and shearing, the microbubbles are evenly dispersed in the molten glass, preventing the bubbles from floating up and agglomerating due to buoyancy and overflowing the system, and ensuring that the volume of the bubbles remains stable in the range of 9.5% to 15.2%. The rapid cooling process quickly locks the size and distribution of the bubbles, controlling the bubble diameter to within 1 μm, laying the foundation for the uniform foaming of the glass powder in the future.

[0025] (3) Through the synergistic regulation of “gas-formulation-process”, it can adapt to the needs of diverse scenarios. The neutral / oxidizing atmosphere can not only slow down the decomposition rate of foaming agents such as carbonates and sulfates and avoid the foaming process from getting out of control, but also promote the integration of sulfur elements into the glass network in the form of stable sulfate ions, improve the solubility and retention of sulfur-containing gases, and provide sufficient foaming power for low-density products; the microbubbles pre-stored in the glass powder serve as natural foaming nuclei, which greatly reduces the activation energy required for bubble formation, making it easier for glass particles to expand into spheres at high temperatures, reducing the proportion of solid particles to below 20%, and increasing the hollow spheroidization rate to over 80%.

[0026] (4) Strong market adaptability. To meet the demand for high compressive strength, the content of SiO2 and Al2O3 is optimized to strengthen the glass network structure, and small-sized bubbles are used to achieve a high strength of 130~185MPa; to meet the demand for low density, the content of Na2O is increased to reduce the softening point of glass, and combined with microbubbles with a large volume ratio, ultra-light products with a density as low as 0.11g / cm³ can be prepared.

[0027] (5) Compared with the traditional solid-state process, this technology has achieved a dual breakthrough in performance and cost. While retaining the advantage of the dense network of solid-state glass, it increases the hollow ratio from less than 65% to more than 80%. Under the same true density, the compressive strength of the product is 40% higher than that of the soft chemical method, which fully meets the stringent requirements of high-end fields such as aerospace and deep-sea engineering. There is no need to add expensive foaming agents. By replacing part of the chemical foaming agent with pre-stored microbubbles, the raw material cost is reduced. At the same time, the increase in the hollow ratio reduces the amount of materials used in downstream applications, indirectly reducing the production cost of the end product. Detailed Implementation

[0028] The present invention will be described in detail below with reference to specific embodiments. The illustrative embodiments and descriptions herein are used to explain the invention but are not intended to limit it. Based on the embodiments of the present invention, any modifications, equivalent substitutions, and improvements made by those skilled in the art within the spirit and principles of the invention should be included within the scope of protection of the present invention. The material ratios, upper and lower limits of process parameters, and range values ​​involved in the present invention can all achieve the present invention, and will not be listed individually here.

[0029] Example 1

[0030] (1) Mix the glass batch containing 10kg quartz sand, 2kg borax, 2.1kg calcium carbonate, 0.5kg sodium chloride, 0.1kg magnesium oxide, 0.25kg mirabilite, 0.5kg sodium phosphate, 0.2kg zinc phosphate and 0.5kg alumina evenly (when the sum of the mass of the glass batch components is calculated as 100%, the content of each component is 71.91% SiO2, 6.63% Na2O, 8.45% CaO, 0.72% MgO, 5.25% B2O3, 3.6% Al2O3, 2.09% P2O5, 0.91% ZnO and 0.45% SO3), and set the melting furnace temperature to 1278℃ to melt the glass.

[0031] (2) Nitrogen gas is injected into the molten glass prepared in step 1) through an array of platinum nozzles and stirred; then water quenching is performed to obtain microporous broken glass with an average bubble diameter of 0.59 μm and a bubble volume ratio of 9.7%.

[0032] (3) The microporous glass prepared in step 2 is coarsely crushed into 1-3 mm particles by a double roller crusher; then ground into glass powder with an average particle size D50 of 120 μm by a horizontal ball mill; then ground into glass powder with a maximum particle size of less than 69 μm by a fluidized bed air jet mill; finally, three specifications of microporous glass powder are obtained by a multi-stage air jet classification system, as shown in Table 1.

[0033] (4) The three types of microporous glass powders were hollowed in a high-temperature spheroidizing furnace at a temperature of 1000~1020℃. The properties of the hollow glass microspheres obtained are shown in Table 1.

[0034] Table 1 Physical properties of glass powder and performance of hollow glass microspheres

[0035]

[0036] Example 2

[0037] (1) Mix the glass batch containing 10kg quartz sand, 2kg borax, 2.1kg calcium carbonate, 0.5kg sodium chloride, 0.1kg magnesium oxide, 0.25kg mirabilite, 0.5kg sodium phosphate, 0.2kg zinc phosphate and 0.5kg alumina evenly (when the sum of the mass of the glass batch components is calculated as 100%, the content of each component is 71.91% SiO2, 6.63% Na2O, 8.45% CaO, 0.72% MgO, 5.25% B2O3, 3.6% Al2O3, 2.09% P2O5, 0.91% ZnO and 0.45% SO3), and set the melting furnace temperature to 1278℃ to melt the glass.

[0038] (2) Air is injected into the molten glass prepared in step 1) through an array of platinum nozzles and stirred; then water quenching is performed to obtain microporous broken glass with an average bubble diameter of 0.55 μm and a bubble volume ratio of 15%.

[0039] (3) The microporous glass prepared in step 2 is coarsely crushed into 1-3 mm particles by a double roller crusher; then ground into glass powder with an average particle size D50 of 120 μm by a horizontal ball mill; then ground into glass powder with a maximum particle size of less than 69 μm by a fluidized bed air jet mill; finally, three specifications of microporous glass powder are obtained by a multi-stage air jet classification system, as shown in Table 2.

[0040] (4) The three types of microporous glass powders were hollowed in a high-temperature spheroidizing furnace at a temperature of 1000~1020℃. The properties of the hollow glass microspheres obtained are shown in Table 2.

[0041] Table 2 Physical properties of glass powder and performance of hollow glass microspheres

[0042]

[0043] Example 3

[0044] (1) Mix the glass batch containing 10kg quartz sand, 1.8kg borax, 1.5kg calcium carbonate, 0.6kg sodium carbonate, 0.1kg magnesium carbonate, 1.1kg mirabilite, 0.35kg sodium phosphate and 0.1kg zinc oxide evenly (when the total mass of the glass batch components is calculated as 100%, the content of each component is 76.20% SiO2, 8.03% Na2O, 6.40% CaO, 0.36% MgO, 5.01% B2O3, 1.15% P2O5, 0.76% ZnO and 2.08% SO3), and set the melting furnace temperature to 1340℃ to melt the glass.

[0045] (2) Air is injected into the molten glass prepared in step 1) through an array of platinum nozzles and stirred; then water quenching is performed to obtain microporous broken glass with an average bubble diameter of 0.24 μm and a bubble volume ratio of 14.5%.

[0046] (3) The microporous glass prepared in step 2 is coarsely crushed into 1-3 mm particles by a double roller crusher; then ground into glass powder with an average particle size D50 of 100 μm by a horizontal ball mill; then ground into glass powder with a maximum particle size of less than 85 μm by a fluidized bed air jet mill; finally, three specifications of microporous glass powder are obtained by a multi-stage air jet classification system, as shown in Table 3.

[0047] (4) The three types of microporous glass powders were hollowed in a high-temperature spheroidizing furnace at a temperature of 1035~1050℃. The properties of the hollow glass microspheres obtained are shown in Table 3.

[0048] Table 3 Physical properties of glass powder and performance of hollow glass microspheres

[0049]

[0050] Example 4

[0051] (1) Mix the glass batch containing 10kg quartz sand, 5.0kg borax, 0.3kg potassium feldspar, 0.5kg sodium feldspar, 3.5kg calcium carbonate, 0.3kg calcium chloride, 0.7kg sodium carbonate, 0.08kg magnesium oxide, 1.1kg mirabilite, 0.5kg sodium phosphate, 0.06kg sodium dihydrogen phosphate, 0.4kg zinc phosphate, and 0.4kg alumina evenly (when the total mass of the glass batch components is calculated as 100%, the content of each component is 76.20% SiO2, 8.03% Na2O, 6.40% CaO, 0.36% MgO, 5.01% B2O3, 1.15% P2O5, 0.76% ZnO, and 2.08% SO3), and set the melting furnace temperature to 1165℃ to melt the glass.

[0052] (2) Air is injected into the molten glass prepared in step 1) through an array of platinum nozzles and stirred; then water quenching is performed to obtain microporous broken glass with an average bubble diameter of 0.73 μm and a bubble volume ratio of 12.8%.

[0053] (3) The microporous glass shards prepared in step 2 are coarsely crushed into 1-3 mm particles by a double roller crusher; then ground into glass powder with an average particle size D50 of 150 μm by a horizontal ball mill; then ground into glass powder with a maximum particle size of less than 77 μm by a fluidized bed air jet mill; finally, three specifications of microporous glass powder are obtained by a multi-stage air jet classification system, as shown in Table 4.

[0054] (4) The three types of microporous glass powders were hollowed in a high-temperature spheroidizing furnace at a temperature of 950~980℃. The properties of the hollow glass microspheres obtained are shown in Table 4.

[0055] Table 4 Physical properties of glass powder and performance of hollow glass microspheres

[0056]

[0057] control group

[0058] (1) Mix the glass batch containing 10kg quartz sand, 5.0kg borax, 0.3kg potassium feldspar, 0.5kg sodium feldspar, 3.5kg calcium carbonate, 0.3kg calcium chloride, 0.7kg sodium carbonate, 0.08kg magnesium oxide, 1.1kg mirabilite, 0.5kg sodium phosphate, 0.06kg sodium dihydrogen phosphate, 0.4kg zinc phosphate, and 0.4kg alumina evenly (when the total mass of the glass batch components is calculated as 100%, the content of each component is 76.20% SiO2, 8.03% Na2O, 6.40% CaO, 0.36% MgO, 5.01% B2O3, 1.15% P2O5, 0.76% ZnO, and 2.08% SO3), and set the melting furnace temperature to 1165℃ to melt the glass.

[0059] (2) The crushed glass prepared in step 1 is coarsely crushed into particles of 1-3 mm by a double roller crusher; then it is ground into glass powder with an average particle size D50 of 150 μm by a horizontal ball mill; then it is ground into glass powder with a maximum particle size of less than 77 μm by a fluidized bed air jet mill; finally, three specifications of microporous glass powder are obtained by a multi-stage air jet classification system, as shown in Table 5.

[0060] (3) The three types of microporous glass powders were hollowed in a high-temperature spheroidizing furnace at a temperature of 995~1005℃. The properties of the hollow glass microspheres obtained are shown in Table 5.

[0061] Table 5 Physical properties of glass powder and performance of hollow glass microspheres

[0062]

[0063] In Examples 1 and 2, under the same formulation and microporous glass powder particle size, Example 2 significantly increased the percentage of hollow glass microspheres in the finished product by increasing the proportion of bubble volume in the microporous glass powder. Similarly, as can be seen from Example 4 and the comparative example, when the glass powder does not contain micropores, the prepared product not only has a significantly lower percentage of hollow glass microspheres, but also a significantly higher true density of the hollow glass microspheres. This indicates that the micropores in the glass powder not only significantly improve the proportion of hollow spheroids, but also facilitate bubble expansion.

[0064] In Example 3, the microporous glass powder 1 had a particle size range of 1.07 and a bubble volume ratio of 2.7%. The prepared product contained 83% hollow glass microspheres by mass and had a true density of 0.20 g / cm³. 3 The compressive strength is 11 MPa. In Example 4, the microporous glass powder 2 has a particle size span of 0.56 and a bubble volume ratio of 2.8%. The prepared product has a hollow glass microsphere mass percentage of 88% and a true density of 0.19 g / cm³. 3 The compressive strength was 12.5 MPa. These results indicate that reducing the particle size range of the microporous glass powder is beneficial to both the mass percentage of hollow glass microspheres and the compressive strength of the finished product.

Claims

1. A method for preparing high-quality hollow glass microspheres based on microporous glass powder, characterized in that... The following steps are to be taken: S1, Raw material mixing and melting Mineral powders, inorganic salts, or oxides containing silicon, sodium, calcium, magnesium, boron, aluminum, phosphorus, or zinc are mixed to form a homogeneous glass batch. When the total mass of the glass batch components is calculated as 100%, the content of each component is 58.0~79.0% SiO2, 4.7~11.2% Na2O, 5.0~13.0% CaO, 0.3~1.8% MgO, 3.0~11.0% B2O3, 0~5.0% Al2O3, 1.0~2.5% P2O5, 0.5~1.6% ZnO, and the balance is 0~4.0%. The glass batch is then melted in a frit furnace at 1150~1370℃ to form molten glass. S2, Gas injection - stirring and shearing - cooling and fixing Gas is injected into the molten glass prepared in step S1 using a porous distributor, and stirring is employed to break up the bubbles using the shear force of the stirring, thus promoting a more uniform distribution of bubbles in the molten glass. The molten glass containing the bubbles is then rapidly cooled by a quenching method to complete the bubble fixation process, resulting in microporous glass blocks / sheets with bubble diameters <1μm and a bubble volume ratio of 9.5~15.2%. The quenching method refers to one of water quenching, cooling plate cooling, or rolling mill cooling, to quickly fix the morphology and distribution of bubbles in the molten glass. S3, Grinding-Grading The microporous glass blocks / sheets prepared in step S2 are crushed, ground, and graded to obtain microporous glass powder with a particle size distribution range of <1.1, a maximum particle size of ≤90μm, and a microporous bubble volume ratio of 1.2~3.4%. S4, High-temperature spheroidization The microporous glass powder obtained in step S3 is passed through a high-temperature spheroidizing furnace at 950~1050℃ to complete the hollow spheroidization process of the microporous glass powder, and a hollow glass microsphere product with a mass ratio of >80% is obtained.

2. The method for preparing high-quality hollow glass microspheres based on microporous glass powder as described in claim 1, characterized in that: In step S1, when the total mass of the glass batch components is calculated as 100%, the content of each component is 64.0~73.0% SiO2, 5.5~7.9% Na2O, 8.0~11.0% CaO, 0.6~0.9% MgO, 4.5~7.5% B2O3, 2.0~5.0% Al2O3, 1.6~2.3% P2O5, 0.8~1.3% ZnO, 0.25~0.55% SO3, and the balance is 0~0.5%.

3. The method for preparing high-quality hollow glass microspheres based on microporous glass powder as described in claim 2, characterized in that: In step S2, microporous glass blocks / sheets with an average bubble diameter of 0.51–0.65 μm and a bubble volume percentage of 9.7–15.0% are obtained; in step S3, the microporous glass powder obtained through crushing, grinding, and grading has a maximum particle size of <70 μm; the hollow glass microspheres prepared in step S4 have a density of 0.50–0.65 g / cm³. 3 Its compressive strength is 130~185MPa.

4. The method for preparing high-quality hollow glass microspheres based on microporous glass powder as described in claim 1, characterized in that: In step S1, when the total mass of the glass batch components is calculated as 100%, the content of each component is 75.0~79.0% SiO2, 7.5~10.5% Na2O, 5.0~7.0% CaO, 0.3~0.5% MgO, 3.0~6.5% B2O3, 1.0~1.5% P2O5, 0.7~1.2% ZnO, 1.5~2.8% SO3, and the balance is 0~0.5%.

5. The method for preparing high-quality hollow glass microspheres based on microporous glass powder as described in claim 4, characterized in that: In step S2, microporous glass blocks / sheets with an average bubble diameter of 0.21–0.31 μm and a bubble volume ratio of 13.5–15.5% are obtained; in step S3, the microporous glass powder obtained through crushing, grinding, and grading has a maximum particle size of <85 μm; the hollow glass microspheres prepared in step S4 have a density of 0.11–0.21 g / cm³. 3 The compressive strength is 5.0~12.0MPa.

6. The method for preparing high-quality hollow glass microspheres based on microporous glass powder as described in claim 4, characterized in that: In step S2, microporous glass blocks / sheets with an average bubble diameter of 0.68–0.78 μm and a bubble volume ratio of 12.1–13.5% are obtained; in step S3, the microporous glass powder obtained through crushing, grinding, and grading has a maximum particle size of <77 μm; the hollow glass microspheres prepared in step S4 have a density of 0.19–0.26 g / cm³. 3 The compressive strength is 11.0~18.0MPa.

7. A method for preparing high-quality hollow glass microspheres based on microporous glass powder as described in claims 1, 2, 3, 4, 5, or 6, characterized in that: In step S2, the porous distributor refers to an array of microporous nozzles / tubes that can withstand high temperatures of 1370°C, or a porous special ceramic / metal with interconnected micropores inside.

8. The method for preparing high-quality hollow glass microspheres based on microporous glass powder as described in claim 7, characterized in that: In step S3, the microporous glass blocks / sheets are coarsely crushed using a jaw crusher or a double roll crusher, then finely ground using one or a combination of ball mills, air jet mills, stirred mills, and rod mills. Finally, the microporous glass powder with the required particle size and span is separated by one of physical sieving, air classifying, or wet classification.

9. The method for preparing high-quality hollow glass microspheres based on microporous glass powder as described in claim 8, characterized in that: In step S3, glass powder with an average particle size D50 of 100~150μm is obtained by coarse crushing with a roller crusher, and coarse grinding with a ball mill, stirred mill or rod mill; then fine grinding is carried out with a fluidized bed air jet mill; finally, microporous glass powder with the required particle size and span is sorted by a multi-stage air jet classification system.

10. The method for preparing high-quality hollow glass microspheres based on microporous glass powder as described in claim 9, characterized in that: In step S2, the injected gas is a neutral or oxidizing atmosphere.

Images