A method of measuring the complete melting temperature of an inorganic mixture

Abstract

The application discloses a method for measuring complete melting temperature of inorganic mixture, comprising the following steps: 1) pressing the inorganic mixture into a cylinder; 2) erecting the cylinder obtained in step 1) on a substrate, and placing it into a high-temperature optical dilatometer to be heated and melted, obtaining projection images of the melt at different temperatures, and then obtaining the contact angle θ of the melt and the corresponding temperature T, and the relationship curve of the contact angle θ and the temperature T, and then performing mathematical transformation to obtain the second derivative curve of the contact angle cosine cosθ and the temperature T, and the temperature corresponding to the point on the curve where the ordinate approaches to 0 is the complete melting temperature of the inorganic mixture. The method for measuring the complete melting temperature of the inorganic mixture has the advantages of high accuracy, good adaptability, good repeatability, simple operation, continuous measurement and the like, and has important significance for the production and research and development of inorganic materials.

Description

Technical Field

[0001] This invention relates to the field of inorganic analysis technology, and more specifically to a method for measuring the complete melting temperature of inorganic mixtures. Background Technology

[0002] The production of inorganic materials often involves melting mixed raw materials (e.g., glass production using glass batches; firing ceramic glazes; preparing frits, etc.). Melting is a crucial and complex process, involving a series of physicochemical changes and intricate heat and mass transfer processes; therefore, selecting an appropriate temperature regime is essential. If the melting temperature is too high, a large amount of volatile components in the raw materials will volatilize, leading to significant changes in product properties and unnecessary energy consumption. If the melting temperature is too low, the raw materials will not melt sufficiently, potentially resulting in defects in the finished product (e.g., inclusions and bubbles in glass). Therefore, determining the melting temperature of mixed raw materials is of great importance in the production of inorganic materials.

[0003] The complete melting temperature refers to the temperature at which a solid substance completely transforms into a homogeneous liquid phase. In glass raw material systems, the complete melting temperature is usually calculated based on a liquidus temperature model. However, due to the complexity of glass composition, different chemical components can interact due to eutectic melting, mixed alkali, and other effects, leading to significant discrepancies between calculated results and actual conditions. Thermal analyzers can monitor the heat flow changes caused by the heating of mixed raw materials, thereby determining some characteristic temperature points (e.g., glass transition temperature, crystallization temperature, softening temperature, melting temperature). However, because mixed raw materials contain different components, the melting peak is generally quite wide and may be affected by baseline drift, resulting in inaccurate results. Furthermore, when the raw material is completely melted, the easily fusible components evaporate rapidly, easily damaging the instrument. Therefore, thermal analysis methods based on thermal analyzers have significant limitations.

[0004] Therefore, it is of great significance to develop a method for measuring the complete melting temperature of inorganic mixtures that is accurate, adaptable, and easy to operate. Summary of the Invention

[0005] The purpose of this invention is to provide a method for measuring the complete melting temperature of an inorganic mixture.

[0006] The technical solution adopted in this invention is:

[0007] A method for measuring the complete melting temperature of an inorganic mixture includes the following steps:

[0008] 1) Pressing the inorganic mixture into a cylinder;

[0009] 2) The cylinder obtained in step 1) is erected on the substrate and placed in a high-temperature optical thermal expansion apparatus for heating and melting. Projection images of the melt at different temperatures are obtained. Based on the projection images, the contact angle θ and the corresponding temperature T of the melt are obtained, as well as the relationship curve between the contact angle θ and the temperature T. Then, mathematical transformations are performed to obtain the second derivative of the contact angle cosine cosθ with temperature T (i.e., d). 2 (cosθ) / dT 2 The temperature corresponding to the point on the curve where the vertical coordinate approaches 0 is the complete melting temperature of the inorganic mixture. (The contact angle θ of the melt in the complete molten state has the following relationship with the temperature T: cosθ=A+BT, where A is a constant and B is the slope. Therefore, when the inorganic mixture reaches complete melting, the second derivatives of cosθ and T should approach zero. Reference: Wetting of Ceramics by Liquid Metals, SKRHEE, Journal of the American Ceramics Society. 54(7):332-334).

[0010] Preferably, the inorganic mixture in step 1) contains at least two inorganic substances.

[0011] Preferably, the inorganic substance is one of oxides, hydroxides, inorganic fluorides, borates, and carbonates.

[0012] Preferably, the pressing method in step 1) is dry pressing.

[0013] Preferably, the pressing in step 1) is carried out under a pressure of 4MPa to 20MPa and a holding time of 10s to 120s.

[0014] Preferably, the diameter of the cylinder in step 1) is 2mm to 15mm and the height is 2mm to 15mm.

[0015] Preferably, the diameter and height of the cylinder in step 1) are equal.

[0016] Preferably, the substrate in step 2) is an alumina ceramic sheet.

[0017] Preferably, the heating and melting in step 2) is carried out at a heating rate of 5°C / min to 12°C / min.

[0018] Preferably, the heating and melting in step 2) is carried out in an air atmosphere.

[0019] The beneficial effects of this invention are: This invention uses a high-temperature optical thermal expansion meter to monitor the melting state of inorganic mixtures in real time, obtains the relationship between the contact angle and temperature, and then, through mathematical transformation, finally realizes the measurement of the complete melting temperature of the inorganic mixture. It has the advantages of high accuracy, good adaptability, good repeatability, simple operation, and continuous measurement, which is of great significance for the production and research and development of inorganic materials. Attached Figure Description

[0020] Figure 1 The curve showing the relationship between the contact angle θ of the melt and the temperature T in Example 1 is shown.

[0021] Figure 2 d in Example 1 2 (cosθ) / dT 2 curve.

[0022] Figure 3 The image shows the XRD pattern of the fused block in Example 1.

[0023] Figure 4 The curve showing the relationship between the contact angle θ of the melt and the temperature T in Example 2 is shown.

[0024] Figure 5 d in Example 2 2 (cosθ) / dT 2 curve.

[0025] Figure 6 The image shows the XRD pattern of the fused block in Example 2.

[0026] Figure 7 The curve showing the relationship between the contact angle θ of the melt and the temperature T in Example 3 is shown.

[0027] Figure 8 d in Example 3 2 (cosθ) / dT 2 curve.

[0028] Figure 9 The image shows the XRD pattern of the fused block in Example 3. Detailed Implementation

[0029] The present invention will be further explained and described below with reference to specific embodiments.

[0030] Example 1:

[0031] A method for measuring the complete melting temperature of an inorganic mixture, comprising the following steps:

[0032] 1) An inorganic mixture (composed by mass percentage as follows: SiO2: 31.44%; Al2O3: 2.40%; Na2B4O7·10H2O: 28.30%; K2CO3: 2.45%; Na2CO3: 10.24%; CaCO3: 5.17%; TiO2: 4.74%; CuO: 0.79%; Co3O4: 1.10%; Ni2O3: 0.79%; Fe2O3: 0.46%; MnO2: 0.79%; Li2CO3: 5.14%; Na2SiF6: 6.19%) was injected into a cylindrical mold and then held under pressure of 4.72 MPa for 60 s to obtain a cylinder with a diameter of 3 mm and a height of 3 mm.

[0033] 2) The cylinder obtained in step 1) is erected on an alumina ceramic sheet (1 mm thick) and then placed in a high-temperature optical thermal expansion apparatus. Heating is carried out in air at a controlled heating rate of 10 °C / min until the temperature reaches 912 °C, at which point heating is stopped. Projected images of the melt at different temperatures are obtained. Based on these projection images, the contact angle θ and corresponding temperature T of the melt are obtained, and the relationship curve between the contact angle θ and temperature T is obtained (e.g., ...). Figure 1 As shown, Figure 1 In the small images above, a is the projected image of the melt at temperature T = 618℃, b is the projected image of the melt at temperature T = 704℃, and c is the projected image of the melt at temperature T = 833℃. Further mathematical transformations yield the curve of the second derivative of the contact angle cosine cosθ with temperature T (e.g., ...). Figure 2 (As shown), then find the point on the curve where the vertical coordinate approaches 0, and the corresponding temperature of 833℃ is the complete melting temperature of the inorganic mixture.

[0034] The inorganic mixture (as above) was added to an alumina crucible, then placed in a muffle furnace and heated to 833°C at a heating rate of 10°C / min, held for 10 min, and then quenched to obtain a molten ingot. The molten ingot was then subjected to X-ray diffraction (XRD) analysis, and the obtained XRD pattern is shown below. Figure 3 As shown.

[0035] Depend on Figure 3 It can be seen that the XRD pattern only shows the peak of the steamed bun and no crystalline phase appears, which proves that the inorganic mixture melted at 833℃ has been completely melted, indicating that the inorganic mixture is completely melted at 833℃.

[0036] Example 2:

[0037] A method for measuring the complete melting temperature of an inorganic mixture, comprising the following steps:

[0038] 1) An inorganic mixture (composed of the following components by mass percentage: SiO2: 60.29%; Al(OH)3: 2.39%; Na2B4O7·10H2O: 9.71%; K2CO3: 2.99%; Na2CO3: 13.98%; CaCO3: 2.05%; ZnO: 0.53%; BaCO3: 1.14%; AlF3: 6.92%) was injected into a cylindrical mold and then held under pressure of 4.72 MPa for 60 s to obtain a cylinder with a diameter of 3 mm and a height of 3 mm.

[0039] 2) The cylinder obtained in step 1) is erected on an alumina ceramic sheet (1 mm thick) and then placed in a high-temperature optical thermal expansion apparatus. Heating is carried out in air at a controlled heating rate of 10 °C / min until the temperature reaches 1352 °C. Heating is then stopped. Projected images of the melt at different temperatures are obtained. Based on these projection images, the contact angle θ and corresponding temperature T of the melt are obtained, and the relationship curve between the contact angle θ and temperature T is obtained (e.g., ...). Figure 4 As shown, Figure 4 In the small images above, a is the projected image of the melt at temperature T = 884℃, b is the projected image of the melt at temperature T = 1057℃, and c is the projected image of the melt at temperature T = 1231℃. Further mathematical transformations yield the curve of the second derivative of the contact angle cosθ with respect to temperature T (e.g., ...). Figure 5 (As shown), then find the point on the curve where the vertical coordinate approaches 0, and the corresponding temperature of 1228℃ is the complete melting temperature of the inorganic mixture.

[0040] The inorganic mixture (as above) was added to an alumina crucible, then placed in a muffle furnace and heated to 1228°C at a heating rate of 10°C / min, held for 10 min, and then quenched to obtain a molten ingot. X-ray diffraction analysis was then performed on the molten ingot, and the resulting XRD pattern is shown below. Figure 6 As shown.

[0041] Depend on Figure 6 It can be seen that the XRD pattern only shows the peak of the steamed bun and no crystalline phase appears, which proves that the inorganic mixture melted at 1228℃ has been completely melted, indicating that the inorganic mixture is completely melted at 1228℃.

[0042] Example 3:

[0043] A method for measuring the complete melting temperature of an inorganic mixture, comprising the following steps:

[0044] 1) An inorganic mixture (composed by mass percentage as follows: SiO2: 47.32%; Al2O3: 1.85%; Na2B4O7·10H2O: 21.79%; K2CO3: 1.89%; Na2CO3: 7.88%; CaCO3: 3.97%; TiO2: 3.55%; CuO: 0.61%; Co3O4: 0.85%; Ni2O3: 0.61%; Fe2O3: 0.36%; MnO2: 0.61%; Li2CO3: 3.95%; Na2SiF6: 4.76%) was injected into a cylindrical mold and then held under pressure of 4.72 MPa for 60 s to obtain a cylinder with a diameter of 3 mm and a height of 3 mm.

[0045] 2) The cylinder obtained in step 1) is erected on an alumina ceramic sheet (1 mm thick) and then placed in a high-temperature optical thermal expansion apparatus. Heating is carried out in air at a controlled heating rate of 10 °C / min until the temperature reaches 1002 °C. Heating is then stopped. Projected images of the melt at different temperatures are obtained. Based on these projection images, the contact angle θ and corresponding temperature T of the melt are obtained, and the relationship curve between the contact angle θ and temperature T is obtained (e.g., ...). Figure 7 As shown, Figure 7 In the small images above, a is the projected image of the melt at temperature T = 631℃, b is the projected image of the melt at temperature T = 686℃, c is the projected image of the melt at temperature T = 796℃, and d is the projected image of the melt at temperature T = 923℃. Further mathematical transformations yield the curve of the second derivative of the contact angle cosθ with respect to temperature T (e.g., ...). Figure 8 (As shown), then find the point on the curve where the vertical coordinate approaches 0, and the corresponding temperature of 925℃ is the complete melting temperature of the inorganic mixture.

[0046] The inorganic mixture (as above) was added to an alumina crucible, then placed in a muffle furnace and heated to 925°C at a heating rate of 10°C / min, held for 10 min, and then quenched to obtain a molten ingot. X-ray diffraction analysis was then performed on the molten ingot, and the resulting XRD pattern is shown below. Figure 9 As shown.

[0047] Depend on Figure 9 It can be seen that the XRD pattern only shows the peak of the steamed bun and no crystalline phase appears, which proves that the inorganic mixture melted at 925℃ has been completely melted, indicating that the inorganic mixture is completely melted at 925℃.

[0048] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. A method for measuring the complete melting temperature of an inorganic mixture, characterized in that, Includes the following steps: 1) Pressing the inorganic mixture into a cylinder; 2) The cylinder obtained in step 1) is erected on the substrate and placed in a high-temperature optical thermal expansion instrument for heating and melting. Projected images of the melt at different temperatures are obtained. The contact angle θ and the corresponding temperature T of the melt are obtained from the projected images, and the relationship curve between the contact angle θ and the temperature T is obtained. Then, a mathematical transformation is performed to obtain the second derivative curve of the contact angle cosine cosθ and the temperature T. The temperature corresponding to the point on the curve where the vertical coordinate approaches 0 is the complete melting temperature of the inorganic mixture.

2. The method for measuring the complete melting temperature of an inorganic mixture according to claim 1, characterized in that: Step 1) The inorganic mixture contains at least two inorganic substances.

3. The method for measuring the complete melting temperature of an inorganic mixture according to claim 2, characterized in that: The inorganic substance is one of oxides, hydroxides, inorganic fluorides, borates, and carbonates.

4. The method for measuring the complete melting temperature of an inorganic mixture according to any one of claims 1 to 3, characterized in that: Step 1) describes a pressing method called dry pressing.

5. The method for measuring the complete melting temperature of an inorganic mixture according to claim 4, characterized in that: Step 1) The pressing is carried out under a pressure of 4MPa to 20MPa and the holding time is 10s to 120s.

6. The method for measuring the complete melting temperature of an inorganic mixture according to any one of claims 1 to 3, characterized in that: Step 1) The diameter of the cylinder is 2mm to 15mm and the height is 2mm to 15mm.

7. The method for measuring the complete melting temperature of an inorganic mixture according to claim 6, characterized in that: Step 1) The diameter and height of the cylinder are equal.

8. The method for measuring the complete melting temperature of an inorganic mixture according to claim 1, characterized in that: Step 2) The substrate is an alumina ceramic sheet.

9. The method for measuring the complete melting temperature of an inorganic mixture according to claim 1 or 8, characterized in that: Step 2) The heating and melting process is carried out at a heating rate of 5℃ / min to 12℃ / min.

10. The method for measuring the complete melting temperature of an inorganic mixture according to claim 1 or 8, characterized in that: Step 2) describes heating and melting that takes place in an air atmosphere.

Images