Preparation method of magnetic hollow glass beads

Abstract

The invention discloses a preparation method of magnetic hollow glass beads, and belongs to the technical field of functional material preparation. Comprising the following steps: 1, mixing various glass forming raw materials, melting at 1400-1600 DEG C to obtain molten glass, and carrying out water quenching, crushing and grading to obtain magnetic glass powder; step 2, mixing magnetic glass powder with the paste according to a mass ratio of 1: (1-2.5), adding sodium dodecyl benzene sulfonate, and performing spray granulation to form magnetic precursor particles; 3, placing the precursor particles in a negative pressure spheroidizing furnace, and carrying out foaming and spheroidizing treatment; and then, carrying out hydrofluoric acid surface etching on the obtained microbeads to form a frosted layer, coating the frosted layer with a barium ferrite magnetized layer, and carrying out separation and collection by a specific gravity separation method to obtain the magnetic glass microbeads.

Description

Technical Field

[0001] This invention belongs to the field of functional material preparation technology, specifically, it relates to a method for preparing magnetic hollow glass microspheres. Background Technology

[0002] Hollow glass microspheres are micron-sized glass spherical materials with a hollow structure, exhibiting a series of excellent properties such as low density, excellent thermal and sound insulation, resistance to high and low temperatures, good electrical insulation, high thermal stability, and resistance to chemical corrosion. Based on these properties, hollow glass microspheres can be used as functional fillers in resin-based composite materials, such as for the preparation of deep-sea buoyancy materials and high-performance thermal insulation materials. In the field of building materials, they can be used to formulate low-density cement slurries and drilling fluids, helping to solve technical problems in deep well cementing and drilling. In addition, this material also has broad application potential in special functional materials such as aerospace ablation protection, hydrogen storage media, and electromagnetic shielding.

[0003] Magnetic hollow glass microspheres are multifunctional composite materials prepared by introducing magnetic components (such as iron oxide) through surface modification or integral composite methods while retaining the characteristics of hollow glass microspheres. This material combines the lightweight, heat insulation, and good dispersibility of hollow glass microspheres with the external magnetic response characteristics of magnetic materials, thus significantly expanding its application range in high-tech fields such as targeted delivery, separation and recovery, and intelligent sensing.

[0004] Currently, common methods for magnetic modification of hollow glass microspheres mainly include surface modification techniques such as hydrothermal methods, magnetron sputtering, and chemical plating. While these methods each have their own characteristics, they also have significant limitations: for example, hydrothermal methods produce relatively uniform coatings, but have long reaction cycles and low efficiency; magnetron sputtering can achieve precise coatings, but the equipment cost is high and the process is complex; chemical plating has a relatively low cost, but the resulting magnetic layer has weak bonding strength and is prone to detachment, leading to unstable magnetic properties. Furthermore, traditional integrated fabrication processes such as powder melting and template methods also generally suffer from problems such as uneven magnetic distribution, difficulty in coordinating the control of microsphere density and magnetic properties, and high fabrication costs.

[0005] Therefore, in order to solve the above problems, the present invention provides a method for preparing magnetic hollow glass microspheres. Summary of the Invention

[0006] The purpose of this invention is to overcome the shortcomings of the prior art and provide a method for preparing magnetic hollow glass microspheres.

[0007] The objective of this invention can be achieved through the following technical solutions: A method for preparing magnetic hollow glass microspheres includes the following steps: Step 1: Mix various glass forming raw materials and melt them into glass liquid at 1400-1600℃. After water quenching, crushing and grading, magnetic glass powder is obtained. Step 2: Mix magnetic glass powder and paste at a mass ratio of 1:1-2.5, and add sodium dodecylbenzenesulfonate at a mass ratio of 0.1-0.5% of the magnetic glass powder. Then, form magnetic precursor particles by spray granulation. Step 3: Place the precursor particles in a negative pressure spheroidizing furnace and complete the foaming and spheroidizing treatment under process conditions of 1200-1400℃ and 0.02-0.08MPa; then, etch the surface of the obtained microspheres with hydrofluoric acid to form a frosted layer, then coat them with a barium ferrite magnetization layer, and finally separate and collect them by gravity separation to obtain magnetic glass microspheres.

[0008] More preferably, the composition of the glass-forming raw materials includes, by weight, 58-60 parts of quartz sand, 14-18 parts of boric acid, 9-12 parts of calcium carbonate, 8-12 parts of soda ash, 1-2 parts of sodium sulfate, and 8-10 parts of iron oxide.

[0009] More preferably, the paste is composed of the following components: by weight, 2-6 parts starch, 2-6 parts cellulose, and 80-100 parts deionized water.

[0010] Ideally, the density of the magnetic glass microspheres is 0.68-0.98 g / cm³. 3 The saturation magnetization is 29-42 emu / g.

[0011] The etching process parameters are optimized as follows: temperature 20-40℃, time 1-5min, wherein the concentration of hydrofluoric acid is 3-6wt%.

[0012] The beneficial effects of this invention are: The method for preparing magnetic hollow glass microspheres provided by this invention achieves uniform and integrated composite of magnetic components in the matrix by co-melting magnetic materials and glass matrix, fundamentally overcoming the problem of weak bonding of magnetic layers in surface coating methods. Furthermore, by utilizing a continuous process combining magnetic glass powder granulation with flame flotation, foaming, spheroidization, and hollowing are completed simultaneously in a single process, significantly simplifying production steps. It also allows for direct and flexible synergistic control of microsphere density and magnetic properties by adjusting the raw material ratio. Simultaneously, flotation treatment under controlled negative pressure effectively promotes uniform heating and stable molding of precursor particles, thereby significantly improving the sphericity, structural consistency, and overall yield of the product. Detailed Implementation

[0013] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0014] Example 1 Step 1: Weigh the following raw materials by mass: 60kg quartz sand, 15kg boric acid, 10kg calcium carbonate, 8kg iron(III) oxide, 10kg soda ash, and 1.5kg sodium sulfate. Prepare the batch according to these components and melt the glass according to the following melting process: heat from room temperature to 1100℃ in 2 hours; heat from 1100℃ to 1550℃ in 2.5 hours, hold for 2 hours, and stir and homogenize. Open the furnace, discharge the material, quench in water, dry, and crush and classify to D50=20μm to obtain magnetic glass powder. Step 2: Mix magnetic glass powder with paste (containing 4 kg starch, 5 kg cellulose, and 91 kg water) at a ratio of 1:2, add 0.2 kg sodium dodecylbenzenesulfonate as a dispersant to improve particle flowability, mix and spray dry to obtain magnetic precursor particles; Step 3: Under 1300℃ and 0.05MPa negative pressure, the magnetic precursor particles were hollowed out in a beading furnace, and then collected by a cyclone collector and a bag filter. The collected glass powder was separated into hollow glass microspheres by gravity separation. The density of the obtained hollow microspheres was 0.78 g / cm³. 3 The surface of the microspheres was etched with 5wt% hydrofluoric acid at a temperature of 25℃ for 2 minutes. After etching, the microspheres were quickly transferred into a large amount of flowing deionized water for strong rinsing and drying. The microspheres with the frosted layer formed by etching were coated with a barium ferrite magnetization layer by the sol-gel method, with a saturation magnetization of 35 emu / g.

[0015] Example 2 Step 1: Weigh the following raw materials by mass: 80kg quartz sand, 18kg boric acid, 12kg calcium carbonate, 10kg iron(III) oxide, 12kg soda ash, and 1.8kg sodium sulfate. Prepare the batch according to these components and melt the glass according to the following melting process: heat from room temperature to 1100℃ in 2 hours; heat from 1100℃ to 1550℃ in 2.5 hours, hold for 2 hours, and stir and homogenize. Open the furnace, discharge the material, quench in water, dry, and crush and classify to D50=20μm to obtain magnetic glass powder. Step 2: Mix magnetic glass powder with paste (containing 5 kg starch, 6 kg cellulose, and 89 kg water) at a ratio of 1:2, add 0.3 kg sodium dodecylbenzenesulfonate as a dispersant to improve particle flowability, mix and spray dry to obtain magnetic precursor particles; Step 3: Under 1300℃ and 0.05MPa negative pressure, the magnetic precursor particles were hollowed out in a beading furnace, and then collected by a cyclone collector and a bag filter. The collected glass powder was separated into hollow glass microspheres by gravity separation. The density of the obtained hollow microspheres was 0.68 g / cm³. 3 The surface of the microspheres was etched with 3wt% hydrofluoric acid at a temperature of 20℃ for 1 minute. After etching, the microspheres were quickly transferred into a large amount of flowing deionized water for strong rinsing and drying. The microspheres with the etched frosted layer were then coated with a barium ferrite magnetization layer by the sol-gel method, with a saturation magnetization of 29 emu / g.

[0016] Example 3 Step 1: Weigh the following raw materials by mass: 58 kg of quartz sand, 14 kg of boric acid, 9 kg of calcium carbonate, 10 kg of iron(III) oxide, 8.8 kg of soda ash, and 1.4 kg of sodium sulfate. Prepare the batch according to these components and melt the glass according to the following melting process: heat from room temperature to 1100℃ in 2 hours; heat from 1100℃ to 1550℃ in 2.5 hours, hold for 2 hours, and stir and homogenize. Then, open the furnace, discharge the material, quench it in water, dry it, and crush and classify it to D50 = 20 μm to obtain magnetic glass powder. Step 2: Mix magnetic glass powder with paste (containing 4 kg starch, 5 kg cellulose, and 91 kg water) at a ratio of 1:2, add 0.2 kg sodium dodecylbenzenesulfonate as a dispersant to improve particle flowability, mix and spray dry to obtain magnetic precursor particles; Step 3: Under 1300℃ and 0.05MPa negative pressure, the magnetic precursor particles were hollowed out in a beading furnace, and then collected by a cyclone collector and a bag filter. The collected glass powder was separated into hollow glass microspheres by gravity separation. The density of the obtained hollow microspheres was 0.98 g / cm³. 3 The surface of the microspheres was etched with 6wt% hydrofluoric acid at a temperature of 30℃ for 5 minutes. After etching, the microspheres were quickly transferred into a large amount of flowing deionized water for strong rinsing and drying. The microspheres with the frosted layer formed by etching were coated with a barium ferrite magnetization layer by the sol-gel method, with a saturation magnetization of 42 emu / g.

[0017] In the description of this specification, the references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0018] The above description is merely an example and illustration of the present invention. Those skilled in the art can make various modifications or additions to the specific embodiments described, or use similar methods to replace them, as long as they do not deviate from the invention or exceed the scope defined in the claims, all of which should fall within the protection scope of the present invention.

Claims

1. A method for preparing magnetic hollow glass microspheres, characterized in that, Includes the following steps: Step 1: Mix various glass forming raw materials and melt them into glass liquid at 1400-1600℃. After water quenching, crushing and grading, magnetic glass powder is obtained. Step 2: Mix magnetic glass powder and paste at a mass ratio of 1:1-2.5, and add sodium dodecylbenzenesulfonate at a mass ratio of 0.1-0.5% of the magnetic glass powder. Then, form magnetic precursor particles by spray granulation. Step 3: Place the precursor particles in a negative pressure spheroidizing furnace and complete the foaming and spheroidizing treatment under process conditions of 1200-1400℃ and 0.02-0.08MPa; then, etch the surface of the obtained microspheres with hydrofluoric acid to form a frosted layer, then coat them with a barium ferrite magnetization layer, and finally separate and collect them by gravity separation to obtain magnetic glass microspheres.

2. The method for preparing magnetic hollow glass microspheres according to claim 1, characterized in that, The glass-forming raw materials comprise, by weight, 58-60 parts of quartz sand, 14-18 parts of boric acid, 9-12 parts of calcium carbonate, 8-12 parts of soda ash, 1-2 parts of sodium sulfate, and 8-10 parts of iron oxide.

3. The method for preparing magnetic hollow glass microspheres according to claim 1, characterized in that, The paste is composed of the following components: by weight, 2-6 parts starch, 2-6 parts cellulose, and 80-90 parts deionized water.

4. The method for preparing magnetic hollow glass microspheres according to claim 1, characterized in that, The density of the magnetic glass microspheres is 0.68-0.98 g / cm³. 3 The saturation magnetization is 29-42 emu / g.

5. The method for preparing magnetic hollow glass microspheres according to claim 1, characterized in that, The etching process parameters are: temperature 20-40℃, time 1-5min, wherein the concentration of hydrofluoric acid is 3-6wt%.