Method for preparing high-strength and high-glossiness glazed microcrystalline glass from granite sludge
By adding modifiers and crystal nucleating agents to the granite mud slag, combined with dense sintering and controlled crystallization, high-strength, high glossy glazed microcrystalline glass is prepared, which solves the problems of low utilization rate of granite mud slag and high energy consumption of microcrystalline glass, and realizes the application of high-end building decorative materials.
Patent Information
- Application Number
- CN202510492172.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-18
- Publication Date
- 2025-07-29
AI Technical Summary
Granite mud slag is generated in large quantities during mining and secondary processing, with low comprehensive utilization rate, and the existing microcrystalline glass preparation methods have high energy consumption and poor decorative properties, which cannot meet the needs of high-end building decorative materials.
The granite sludge slag with ball-milled iron was used as raw materials, and the modifiers Ca(OH)2 and MgO, as well as the crystal nucleants TiO2 and ZrO2 were added. High-strength, high-gloss and high-gloss glaze surface microcrystalline glass was prepared through dense sintering, instantaneous glaze firing and low-temperature controlled crystallization.
It realizes the preparation of high-strength, high-gloss glazed microcrystalline glass with low energy consumption and high efficiency, with excellent mechanical properties and decorative properties, and is suitable for high-end architectural decorative materials.
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Figure CN120383430A_ABST
Abstract
Description
Technical Field
[0001] The present invention belongs to the field of solid waste resource utilization, and particularly relates to a method for preparing high-strength and high-gloss glazed glass-ceramics from granite sludge. Background Art
[0002] Granite is an acidic volcanic rock formed by the loss of heat and condensation of magma deep underground, mainly composed of minerals such as quartz and feldspar. Granite has excellent physical and mechanical properties, high hardness and strength, corrosion resistance and wear resistance, is not easily weathered and has a certain heat resistance, and is a high-quality building decoration stone. A large amount of sludge is generated during the mining and subsequent secondary processing of granite. Its powder particles are fine, hard, and have a complex composition, and the comprehensive utilization rate is relatively low. The stacking and burial of sludge have serious negative impacts on soil fertility, air quality, and groundwater quality, resulting in resource waste and environmental burden.
[0003] Granite sludge is mainly used in fields such as building materials (permeable bricks, concrete, cement, etc.), ceramics and glass-ceramics, industrial fillers, and refractory materials (Research progress on the resource utilization of granite waste [J]. Chemical Engineering Minerals & Processing 2023;52(3):45-52+59). The resource utilization rate of granite sludge at home and abroad is relatively low, and its potential economic value has not been fully explored. In recent years, glass-ceramics made from mineral waste have been widely used in high-tech fields such as high-grade building building materials, microelectronic materials, and aviation heat-resistant materials due to their good chemical stability, high hardness, excellent mechanical properties, simple preparation process, and low cost.
[0004] For granite waste, glass-ceramics with a flexural strength of 70.2 MPa were prepared by the melting-crystallization method {Crystallization process of glass-ceramics from granite waste [J]. Journal of the Chinese Ceramic Society, 2016, 44(4): 601-606.}. The glass-ceramics prepared by the melting-crystallization method have high density and excellent mechanical properties, but the energy consumption is high during the high-temperature melting process of the glass batch. The fiber-reinforced anorthite glass-ceramics sintered from granite powder have a flexural strength and fracture toughness of 144 MPa and 3.0 MPa×m 1 / 2 {Study on the toughening of anorthite glass-ceramics sintered from granite powder [J]. Bulletin of the Chinese Ceramic Society, 2019, 38(02): 450-453+458}. The powder sintering method has low energy consumption and simple process, but its sintered density is poor, lacks decorative effects, and cannot be used in building decoration materials.
[0005] In the present invention, a modifier and a nucleating agent are added to the ball-milled iron-removed powder of granite sludge, and through dense sintering, instantaneous glaze firing, and combined with controlled crystallization at low temperature, a high-strength and high-gloss glazed glass-ceramic is prepared. It not only has low energy consumption, but also improves the flexural strength and surface gloss of the glass-ceramic at the same time, making its mechanical properties and decorative properties far superior to those of high-grade decorative materials such as glazed tiles on the market. It has a broad application field in high-grade building building materials and helps to realize the high-value utilization of granite sludge. Summary of the Invention
[0006] The purpose of the present invention is to provide a method for preparing a high-strength and high-gloss glazed glass-ceramic from granite sludge. Different from the traditional melting-crystallization method and powder sintering method for preparing glass-ceramics, the present invention uses ball-milled iron-removed granite sludge as the main raw material, Ca(OH)2 and MgO as modifiers, and TiO2 and ZrO2 as nucleating agents. After mixing the modifiers and nucleating agents with the granite sludge and granulating, it is molded into a green body, and through dense sintering and instantaneous glaze firing, a glazed glass-ceramic is obtained, and controlled crystallization is carried out by heat treatment at low temperature to prepare a high-strength and high-gloss glazed glass-ceramic.
[0007] When densely sintered at 1100 °C, albite in the granite melts to form a liquid glass phase, and CaO and MgO pyrolyzed from Ca(OH)2 dissolve in the glass liquid, reducing the viscosity of the glass melt and promoting dense sintering of the liquid phase; when instantaneously glaze fired at 1300 °C, the high temperature further reduces the viscosity of the glass liquid on the surface of the sintered body, promoting quartz and feldspar in the powder to gradually dissolve in the glass liquid to form a surface glaze layer; at the same time, the high temperature of glaze firing is conducive to the dissolution of high-refractive-index TiO2 and ZrO2 nucleating agents, and the surface gloss increases after glaze firing. When controlled crystallization occurs at low temperature, under the action of the nucleating agent, a large number of columnar and fibrous diopside are precipitated from the glass phase, significantly improving the flexural strength of the glazed glass-ceramic. The precipitation of diopside increases the Al / Si ratio of the glass phase in the glaze layer and the refractive index, thereby further improving the surface gloss of the glazed glass-ceramic.
[0008] A method for preparing a high-strength and high-gloss glazed glass-ceramic from granite sludge, the process steps are as follows: The granite sludge is ball-milled and pulverized in distilled water to obtain a ball-milled slurry; The ball-milled slurry is physically iron-removed to remove colored iron-containing minerals, and after washing and drying, a ball-milled powder is obtained; A modifier and a nucleating agent are added to the ball-milled powder, and mechanically mixed evenly to obtain a mixed powder; The mixed powder is granulated and molded by pressing. The powder green body is subjected to dense sintering and instantaneous glaze firing to obtain a glazed glass-ceramic; The glazed glass-ceramic is subjected to controlled crystallization to prepare a high-strength and high-gloss glazed glass-ceramic.
[0009] The mass percentages of the components in the mixed powder are as follows: 88% - 95% of granite powder, 1% - 5% of modifier, and 4% - 7% of nucleating agent.
[0010] The modifier is a mixed powder of Ca(OH)2 and MgO, and the mass ratio of the two is 1:2. The nucleating agent is a mixed powder of TiO2 and ZrO2, and the mass ratio of the two is 5:3. The dense sintering temperature is 1100°C, and the holding time is 2h. The instantaneous glaze firing temperature is 1300°C, and the holding time is 0. The controlled devitrification temperature is 930°C - 960°C, and the holding time is 2h.
[0011] Compared with the traditional melting - devitrification method and sintering method, the present invention prepares high - strength and high - gloss glazed microcrystalline glass by adding an external modifier and a nucleating agent, and adopting dense sintering, instantaneous glaze firing combined with controlled devitrification, which has substantial innovations in the preparation method, component composition and the properties of microcrystalline glass. The beneficial effects are as follows: (1) Using granite sludge powder as the main raw material, adopting dense sintering, instantaneous glaze firing combined with controlled devitrification, without high - temperature melting, having the effect of energy conservation and emission reduction; (2) In the present invention, Ca(OH)2 and MgO modifiers are added, which reduce the viscosity of the glass phase during the sintering process, promote the dense sintering of microcrystalline glass, and at the same time improve the glass flowability in the glaze layer and increase the surface gloss of the glaze layer; (3) In the present invention, TiO2 and ZrO2 nucleating agents with high refractive index are added. The nucleating agent dissolves into the glass phase, which not only improves the surface gloss of the glaze layer, but also endows the glazed microcrystalline glass with devitrification ability. During low - temperature heat treatment, controlled devitrification occurs, and columnar and fibrous diopside are precipitated, further improving the flexural strength and gloss of the glazed microcrystalline glass, and obtaining high - strength and high - gloss glazed microcrystalline glass.
[0012] In summary, the present invention has a high utilization rate of granite sludge, low production energy consumption, the surface of the glazed microcrystalline glass has a beautiful luster and good decoration, and has excellent mechanical properties, and is expected to be applied to high - grade building decoration materials to realize the high - value utilization of granite sludge. Brief Description of the Drawings
[0013] Figure 1 is the preparation process flow chart of the glazed microcrystalline glass.
[0014] Figure 2 is the XRD pattern of the glazed microcrystalline glass before and after heat treatment in Example 1.
[0015] Figure 3 is the SEM photo of the glazed microcrystalline glass in Example 1.
[0016] Figure 4 is the physical photo of the glazed microcrystalline glass in Example 1. Detailed implementation mode
[0017] The present invention is further illustrated by the following specific implementation examples, but the content of the present invention is not limited to the content involved in the examples only.
[0018] The technological process of preparing high-strength and high-gloss glazed microcrystalline glass from granite mud residue of the present invention is as Figure 1 shown. Using Ca(OH)2 and MgO as modifiers and high-refractive-index TiO2 and ZrO2 as nucleating agents, they are mixed with the iron-removed granite mud residue by ball milling to obtain a uniformly mixed powder. After granulating the mixed powder, it is molded into a green body by die pressing and sintered step by step in a muffle furnace to obtain the glazed microcrystalline glass. Then, the glazed microcrystalline glass is subjected to controlled crystallization at a low temperature to prepare the high-strength and high-gloss glazed microcrystalline glass.
[0019] Example 1 The mass percentages of the selected raw material components are as follows: 90% of the iron-removed granite mud residue by ball milling, 3% of the modifier, where the modifier is a mixed powder of Ca(OH)2 and MgO, and the mass ratio of the two is 1:2; 7% of the nucleating agent, where the nucleating agent is a powder composed of TiO2 and ZrO2, and the mass ratio of the two is 5:3. The same material selection and ratio are made for the modifier and the nucleating agent in each example; after mechanically mixing the above granite mud residue, modifier, and nucleating agent evenly, granulating, and die pressing into a green body, it is placed in a muffle furnace and sintered densely at 1100 °C for 2 h, and then heated to 1300 °C for instantaneous sintering (without heat preservation) to obtain the glazed microcrystalline glass; the glazed microcrystalline glass is subjected to controlled crystallization at 950 °C for 2 h to obtain the high-strength and high-gloss glazed microcrystalline glass. The bulk density of the glazed microcrystalline glass is measured by the Archimedes drainage method to be 2.35 g / cm 3 , and the water absorption rate is 0.8%; the flexural strength of the glazed microcrystalline glass is measured by a ceramic bending testing machine to be 85.2 MPa; the surface glossiness of the glazed microcrystalline glass is measured by a surface glossiness meter to be 105.8 GU.
[0020] Using an X-ray diffractometer (XRD) to analyze the crystal phase composition of the glazed microcrystalline glass before and after heat treatment, as Figure 2 shown. The crystallinity of the glazed microcrystalline glass before heat treatment is 9.3%, and after controlled crystallization at 950 °C, the crystallinity increases to 28.9%. The main crystal phases precipitated are diopside, rutile, and baddeleyite. Using a field emission scanning electron microscope (FESEM) to observe the morphology of the glazed microcrystalline glass, as Figure 3 shown, the crystalline phase is mainly columnar diopside, with a size of 0.3 - 0.5 mm; at the same time, fibrous diopside appears, with a length of 0.4 - 1 mm and a diameter of about 40 nm. Figure 4 is a physical photograph of the glazed microcrystalline glass. The surface of the glaze layer is very smooth and flat, showing an overall milky white color and excellent decorative effects.
[0021] Example 2 The mass percentages of the selected raw material components are as follows: 92% of ball-milled iron-removed granite sludge, 4% of modifier, and 4% of nucleating agent. After mechanical mixing evenly, granulation is carried out, and then it is molded into a green body. It is densely sintered at 1100 °C for 2 h in a muffle furnace, and then continuously heated to 1300 °C for instantaneous sintering (without heat preservation) to obtain glazed glass-ceramics; the glazed glass-ceramics are subjected to controlled crystallization at 950 °C for 2 h to obtain high-strength and high-gloss glazed glass-ceramics. The bulk density of the glazed glass-ceramics is measured by the Archimedes drainage method to be 2.28 g / cm 3 , and the water absorption rate is 1.2%; the flexural strength of the glazed glass-ceramics is measured by a ceramic bending testing machine to be 81.2 MPa; the surface glossiness of the glazed glass-ceramics is measured by a surface glossiness meter to be 112.8 GU.
[0022] Example 3 The mass percentages of the selected raw material components are as follows: 88% of ball-milled iron-removed granite sludge, 5.5% of modifier, and 6.5% of nucleating agent. After mechanical mixing evenly, granulation is carried out, and then it is molded into a green body. It is placed in a muffle furnace and densely sintered at 1100 °C for 2 h, and then continuously heated to 1300 °C for instantaneous sintering (without heat preservation) to obtain glazed glass-ceramics; the glazed glass-ceramics are subjected to controlled crystallization at 950 °C for 2 h to obtain high-strength and high-gloss glazed glass-ceramics. The bulk density of the glazed glass-ceramics is measured by the Archimedes drainage method to be 2.32 g / cm 3 , and the water absorption rate is 0.8%; the flexural strength of the glazed glass-ceramics is measured by a ceramic bending testing machine to be 88.6 MPa; the surface glossiness of the glazed glass-ceramics is measured by a surface glossiness meter to be 99.6 GU.
[0023] It should be noted that those skilled in the art of this technology can make various improvements and refinements to the described specific embodiments or use similar methods for substitution. As long as they do not deviate from the concept of the invention or exceed the scope defined by this claim book, they should all fall within the protection scope of the present invention.
Claims
1. A method for preparing high-strength and high-gloss glazed glass-ceramics from granite sludge, the steps are as follows: S1. The granite sludge is ball-milled and pulverized in distilled water to obtain a ball-milled slurry; S2. The ball-milled slurry is physically de-ironed to remove colored iron-containing minerals. After washing and drying, a ball-milled powder is obtained; S3. Add a modifier and a nucleating agent to the ball-milled powder, and mechanically mix them evenly to obtain a mixed powder; ； S4. The mixed powder is granulated and molded by pressing. The green body of the powder is subjected to dense sintering and instantaneous glaze firing to obtain glazed glass-ceramics; S5. The glazed glass-ceramics are subjected to controlled crystallization to prepare high-strength and high-gloss glazed glass-ceramics.
2. The method according to claim 1, characterized in that: In step S3, the mass percentages of each component in the mixed powder are: 88% - 95% of granite powder, 1% - 5% of modifier; 4% - 7% of nucleating agent.
3. The method according to claim 1, characterized in that: In step S3, the modifier is a mixed powder of Ca(OH)2 and MgO, and the mass ratio of the two is 1:
2. The nucleating agent is a mixed powder of TiO2 and ZrO2, and the mass ratio of the two is 5:
3. In step S4, the dense sintering temperature is 1100°C, and the constant temperature time is 2h; the instantaneous glaze firing temperature is 1300°C, and the constant temperature time is 0; in step S5, the controlled crystallization temperature is 950°C, and the constant temperature time is 2h.