Heat-resistant glass-ceramics and preparation method thereof

Abstract

The present invention discloses a heat-resistant microcrystalline glass and a preparation method thereof. The raw materials for preparing the heat-resistant microcrystalline glass include: 58-62 parts by mass of microsilica powder; 10-14 parts by mass of magnesium smelting dust ash; 4-8 parts by mass of aluminum oxide; 5-10 parts by mass of sodium carbonate; 4-6 parts by mass of borax pentahydrate, 2-4 parts by mass of lithium carbonate; 1-3 parts by mass of zinc oxide; 1-2 parts by mass of zirconium oxide; and 3-5 parts by mass of sodium fluorosilicate. The preparation method includes mixing and prefabrication, melt water quenching, ball milling, and high-temperature nucleation and crystallization. The present invention utilizes the complementarity of the two components of microsilica powder and magnesium smelting dust ash to produce a heat-resistant microcrystalline glass in the production system, realizing the transformation of waste into treasure and greatly increasing the added value of the two by-products.

Description

Technical Field

[0001] The present invention belongs to the technical field of inorganic non-metallic materials, and in particular relates to a method for preparing heat-resistant microcrystalline glass from microsilica powder. Background Art

[0002] Heat-resistant glass-ceramics are a solid composite material composed of both glass and microcrystalline phases, produced by targeted crystallization of base glass. Compared to glass and ceramics of the same composition, heat-resistant glass-ceramics boasts high mechanical strength, high hardness, and excellent wear resistance, and is widely used in fields such as construction, electronics, and the chemical industry. However, the traditional raw materials for heat-resistant glass-ceramics are often complex and expensive. Summary of the Invention

[0003] In view of the defects or shortcomings of the prior art, the present invention provides a heat-resistant microcrystalline glass.

[0004] To this end, the raw materials for preparing the heat-resistant microcrystalline glass provided by the present invention include: 58-62 parts by mass of microsilica powder; 10-14 parts by mass of magnesium smelting dust ash; 4-8 parts by mass of aluminum oxide; 5-10 parts by mass of sodium carbonate; 4-6 parts by mass of borax pentahydrate, 2-4 parts by mass of lithium carbonate; 1-3 parts by mass of zinc oxide; 1-2 parts by mass of zirconium oxide; and 3-5 parts by mass of sodium fluorosilicate.

[0005] The present invention's microsilica fume and magnesium smelting dust are both calcined at high temperatures, resulting in highly stable compositions. Neither requires ball milling, and their complementary compositions enable the production of heat-resistant microcrystalline glass in the CMAS (CaO-MgO-Al2O3-SiO2) system, transforming waste into valuable products and significantly increasing the added value of both byproducts. Both microsilica fume and magnesium smelting dust are high-temperature dusts with relatively concentrated compositions, and the production of high-temperature glass does not require the addition of specialized fluxes.

[0006] The heat-resistant microcrystalline glass obtained by the present invention has a ratio of crystals to amorphous phases of (3-5): (5-7), wherein the main crystal phases are mainly β-wollastonite and diopside, and contain 5% to 8% cordierite. The thermal expansion coefficient of the obtained glass material (20 to 700 ° C) is less than 8×10 －7 / ℃; maximum operating temperature 400-500℃ (not less than 30 hours); flexural strength: 62-72Mpa; Mohs hardness: >5.5, acid and alkali resistance <0.015%, which can meet the requirements of heat-resistant microcrystalline glass, such as for induction cooker panels.

[0007] The present invention also provides a method for preparing the heat-resistant glass-ceramics, which comprises:

[0008] First, the raw material components are mixed and pressed into a prefabricated block, and then the prefabricated block is heated to melt, and then the melt is quenched with water to obtain glass particles;

[0009] The glass particles are then ground into glass powder, a binder is then added to the glass powder to obtain a slurry, and the slurry is then pressed into a preform;

[0010] Finally, the obtained preform is heated to 600-750°C for nucleation, then raised to 850-1050°C for crystallization, and then cooled to room temperature in the furnace.

[0011] An optional solution is that the amount of the binder added is 2-5 wt.% of the mass of the glass powder. The binder is selected from acrylic emulsion.

[0012] An optional solution is that the glass powder has a particle size of 100-200 mesh.

[0013] An optional solution is to finally place the obtained preform in a heating furnace, heat it to 600-750℃ at a heating rate of 5-8℃ / min for nucleation for 1-2h, then heat it to 850-1050℃ at the same heating rate for crystallization for 1-2h, and then cool it to room temperature in the furnace. DETAILED DESCRIPTION

[0014] Unless otherwise specified, the scientific and technical terms used herein are understood according to the knowledge of ordinary technicians in the relevant fields.

[0015] In the process of smelting metallic silicon, the silicon vapor generated by high temperature combines with the oxygen in the flue of the electric furnace to form silicon monoxide. After being discharged from the flue, it reacts with the oxygen in the air to generate silicon dioxide vapor, which is quickly condensed into fine spherical particles. It has the properties of fine particles (<1 micron), light weight, large specific surface area, strong volcanic ash activity, and high refractoriness. These dusts are captured and recovered with specific environmentally friendly dust removal equipment to obtain ultrafine amorphous silicon dioxide particles, namely microsilica powder. The main components (mass fraction) of common microsilica powder are: loss on ignition LOSS: 4.00-7.00%; SiO2 85.0-95.0%; Al2O3: 0.73-0.94%, CaO: 1.05-2.17%, MgO: 1.00-1.39%, and the remaining components (P2O5 + TiO2 + MnO + Fe2O3 + K2O) <5.0%. The composition of the microsilica powder used in the following examples is shown in Table 1.

[0016] Table 1

[0017]

[0018] Magnesium smelting dust is the material obtained by bagging and collecting the fine particles (<74 microns) of the reducing raw material powder during the vacuum extraction process in the reduction section of magnesium smelting using the Pidgeon process. Its characteristics are: a defined composition, a relatively fine particle size (<74 microns), and the absence of low-melting or easily ablated chemical components after being subjected to a certain high temperature, resulting in a relatively stable composition overall. Common magnesium smelting dust contains magnesium oxide, calcium oxide, and silicon oxide, the sum of which can account for more than 90%; the main components (by mass fraction) are: MgO 20%-25%; Al2O3 0.5%-2.0%; SiO2 20%-25%; CaO: 40%-50%. The composition of the magnesium smelting dust used in the following examples is shown in Table 2.

[0019] Table 2

[0020]

[0021] The product performance testing method in the following embodiments is as follows:

[0022] (1) The method for detecting the proportion of crystal and amorphous phases and the main crystalline phase of heat-resistant glass-ceramics is to determine the ratio of the crystalline phase to the amorphous phase based on the XRD results;

[0023] (2) Flexural strength, Mohs hardness, acid resistance and alkali resistance, all refer to the standard: [JC / T872-2019];

[0024] (3) Thermal shock resistance, thermal expansion coefficient test reference standard: [QB / T4831-2015].

[0025] Example 1-3:

[0026] The raw materials for preparing the heat-resistant microcrystalline glass plate in this embodiment are: microsilica powder: 62 parts by mass; magnesium smelting dust ash: 12 parts by mass; aluminum oxide: 6 parts by mass; sodium carbonate: 5 parts by mass; borax pentahydrate: 4 parts by mass; lithium carbonate: 4 parts by mass; zinc oxide: 1.5 parts by mass; zirconium oxide: 1.5 parts by mass; and sodium fluorosilicate: 4 parts by mass.

[0027] The preparation process is:

[0028] The prepared raw materials are ball-milled for 1.5 hours. The mixed powder is then pressed into prefabricated blocks of different sizes at a pressure of 25±5 MPa to facilitate subsequent melting. The prefabricated blocks are then placed in a melting device and heated to 1400°C at a heating rate of 5-10°C / min for high-temperature melting. The temperature is then maintained to ensure full melting.

[0029] The molten glass liquid is then directly water quenched to obtain basic glass particles of different sizes;

[0030] The obtained glass particles were ball-milled with the basic glass in a ball mill for 1.5 hours, and sieved to obtain a basic glass powder of 100-200 mesh;

[0031] Then, the basic glass powder is mixed with 3wt.% acrylic emulsion and, under a pressure of about 15MPa, the basic glass powder is slurry-casted into a preform of a certain shape, which can be round, square, or fan-shaped.

[0032] Finally, the preform is placed in a high-temperature furnace, heated to 700°C at a heating rate of 6-7°C / min for nucleation for 1.5 hours, then heated to 950°C at the same rate for crystallization for 2 hours, and then cooled to room temperature in the furnace to obtain a heat-resistant microcrystalline glass product.

[0033] The raw materials for the preparation of Examples 2 and 3 are shown in Table 3, and the preparation processes of each are the same as those of Example 1.

[0034] Table 3

[0035]

[0036] The performance test of the glass prepared in the above examples is shown in Table 4.

[0037] Table 4

[0038]

Claims

1. A heat-resistant glass-ceramic, characterized in that: The raw materials for preparing the heat-resistant microcrystalline glass include: 58-62 parts by mass of microsilica powder; 10-14 parts by mass of magnesium smelting dust ash; 4-8 parts by mass of aluminum oxide; 5-10 parts by mass of sodium carbonate; 4-6 parts by mass of borax pentahydrate, 2-4 parts by mass of lithium carbonate; 1-3 parts by mass of zinc oxide; 1-2 parts by mass of zirconium oxide; and 3-5 parts by mass of sodium fluorosilicate.

2. The method for preparing the heat-resistant glass-ceramics according to claim 1, characterized in that: The preparation method comprises: First, the raw material components are mixed and pressed into a prefabricated block, and then the prefabricated block is heated to melt, and then the melt is quenched with water to obtain glass particles; The glass particles are then ground into glass powder, a binder is then added to the glass powder to obtain a slurry, and the slurry is then pressed into a preform; Finally, the obtained preform is heated to 600-750°C for nucleation, then raised to 850-1050°C for crystallization, and then cooled to room temperature in the furnace.

3. The method for preparing heat-resistant glass-ceramics according to claim 2, wherein: The added amount of the binder is 2-5 wt.% of the mass of the glass powder.

4. The method for preparing heat-resistant glass-ceramics according to claim 2, wherein: The binder is selected from acrylic emulsion.

5. The method for preparing heat-resistant glass-ceramics according to claim 2, wherein: The glass powder has a particle size of 100-200 meshes.

6. The method for preparing heat-resistant glass-ceramics according to claim 2, wherein: Finally, the obtained preform is placed in a heating furnace, heated to 600-750℃ at a heating rate of 5-8℃ / min for nucleation for 1-2h, then heated to 850-1050℃ at the same heating rate for crystallization for 1-2h, and then cooled to room temperature in the furnace.

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