Tailings composite cordierite-based far-infrared emitting ceramics, their preparation methods and applications

Abstract

This invention discloses a cordierite-based far-infrared emitting ceramic composited with tailings, its preparation method, and its applications. The raw material components of the cordierite far-infrared emitting ceramic composited with tailings include tailings, SiO2, MgO, and Al2O3; wherein the tailings include vanadium-titanium magnetite tailings and / or molybdenum tailings. This invention uses readily available and inexpensive tailings as one of the main components, combining them with silicon oxide, magnesium oxide, and aluminum oxide to regulate the crystal molecular formula of cordierite. Some transition metal ions in the vanadium-titanium magnetite tailings and / or molybdenum tailings react with Mg... 2+ With similar radii, they can easily enter the crystal structure and replace the Mg atoms therein. 2+ This leads to lattice distortion and defects, resulting in a decrease in ion vibration symmetry. This allows for the coexistence of polycrystalline phases within the ceramic, improving the infrared emissivity and mechanical properties of cordierite. Its far-infrared emissivity in the 8μm-14μm range can reach over 0.867, and its flexural strength can reach over 49.2MPa.

Description

Technical Field

[0001] This invention belongs to the field of ceramic technology and relates to a tailings composite cordierite-based far-infrared emitting ceramic, its preparation method, and its uses. Background Technology

[0002] Most existing technologies for preparing cordierite ceramics utilize pure oxides for synthesis. This method involves high sintering temperatures (around 1280℃) and high raw material and manufacturing costs. A few other technologies utilize the synergistic effect of pure oxides and minerals to prepare cordierite ceramics. However, this technology has a more complex preparation process and its infrared emissivity needs improvement.

[0003] Far-infrared ceramics are a special type of ceramic material that can emit far-infrared rays of a specific wavelength. The emissivity is usually between 0 and 1. When its far-infrared emissivity is greater than 0.9, it can be classified as a high far-infrared emissivity ceramic material. Generally, its bending strength is greater than 35 MPa.

[0004] CN101538151 discloses a high-infrared-emissivity cordierite ceramic substrate and a high-infrared-emissivity electrothermal composite ceramic heating element. The main raw materials are Al2O3, SiO2, Mg(OH)2, and ZnO. The preparation method involves mixing the raw materials according to a specified ratio, followed by ball milling, drying, granulation, and molding, and then sintering at 1280℃-1350℃ to obtain a Zn-doped high-infrared-emissivity cordierite ceramic substrate. This ceramic electrode exhibits an infrared emissivity exceeding 95% in the 8μm-14μm wavelength range. However, since the main raw materials are all pure chemical reagents and the sintering temperature is high, the cost of raw materials and manufacturing is high, making it unsuitable for industrial production.

[0005] CN109095911A discloses a method for preparing cordierite infrared radiation multiphase ceramics. The method involves first preparing ferrite via a gel method, then mixing it with 87% cordierite and calcined kaolin, and finally sintering at 1200℃ to obtain the cordierite multiphase infrared ceramics. The prepared infrared radiation ceramics exhibit a low coefficient of thermal expansion, good thermal shock resistance, and high infrared radiation performance. However, this method directly uses cordierite as a raw material and employs ferrite prepared via a sol-gel method for doping to improve far-infrared emissivity. This process is complex and unsuitable for large-scale production.

[0006] Therefore, providing a simple and low-cost method for preparing far-infrared emitting ceramics, and enabling the prepared far-infrared emitting ceramics to have high infrared emissivity, is a technical problem that urgently needs to be solved. Summary of the Invention

[0007] In view of the above-mentioned problems existing in the prior art, the purpose of this invention is to provide a tailings composite cordierite-based far-infrared emitting ceramic, its preparation method and uses.

[0008] To achieve the above objectives, the present invention adopts the following technical solution:

[0009] In a first aspect, the present invention provides a cordierite-based far-infrared emitting ceramic composited with tailings, wherein the raw material components of the cordierite-based far-infrared emitting ceramic composited with tailings include tailings, SiO2, MgO and Al2O3.

[0010] The tailings include at least one of vanadium-titanium magnetite tailings and molybdenum tailings.

[0011] This invention uses readily available and inexpensive tailings as one of the main components, combining them with silicon dioxide, magnesium oxide, and aluminum oxide to regulate the crystal molecular formula of cordierite. The principle is as follows: Due to the loose internal structure of the [MgO6] octahedron in cordierite crystals, ion vibrations are prone to asymmetry, resulting in far-infrared emission properties. Furthermore, its loose structure provides favorable conditions for cordierite doping. Some transition metal ions in vanadium-titanium magnetite tailings and / or molybdenum tailings react with Mg... 2+ Their radii (0.066 nm) are similar, such as Fe. 3+ With a radius of 0.0645 nm, it can easily enter the crystal structure and replace the Mg. 2+ This leads to lattice distortion and defects, resulting in a decrease in ion vibration symmetry. This allows for the coexistence of polycrystalline phases within the ceramic, improving the infrared emissivity and mechanical properties of cordierite. Its far-infrared emissivity in the 8μm-14μm range can reach over 0.867, and its flexural strength can reach over 49.2MPa. By optimizing the types and amounts of minerals in the raw materials, the far-infrared emissivity in the 8μm-14μm range can reach over 0.95, and the flexural strength can reach over 67MPa.

[0012] This invention reuses accumulated tailings resources, turning waste into treasure and reducing production costs. Furthermore, since vanadium-titanium magnetite tailings and molybdenum tailings contain fluxing agents (such as K₂O and Na₂O), the sintering temperature can be significantly reduced. This invention can obtain high-performance far-infrared emitting ceramics at lower sintering temperatures, greatly reducing production energy consumption. The preparation process of this invention is simple, the production cost is low, and it is suitable for industrial production.

[0013] In this invention, the source of the tailings is not specifically limited; for example, it can be molybdenum tailings and vanadium-titanium magnetite tailings from the Chengde area.

[0014] The following are preferred technical solutions of the present invention, but are not intended to limit the technical solutions provided by the present invention. The technical objectives and beneficial effects of the present invention can be better achieved and realized through the following preferred technical solutions.

[0015] Preferably, based on the total mass of the raw materials of the cordierite-based far-infrared emitting ceramic composited with tailings as 100%, the mass fraction of each component is as follows:

[0016]

[0017] In this invention, the mass fraction of molybdenum tailings is 0-30 wt.%, for example, it can be 1 wt.%, 3 wt.%, 5 wt.%, 10 wt.%, 15 wt.%, 20 wt.%, 25 wt.%, or 30 wt.%.

[0018] In this invention, the mass fraction of vanadium-titanium magnetite tailings is 0-40 wt.%, for example, 1 wt.%, 3 wt.%, 5 wt.%, 10 wt.%, 15 wt.%, 20 wt.%, 25 wt.%, 30 wt.%, 35 wt.%, or 40 wt.%.

[0019] In this invention, the mass fraction of SiO2 is 20wt.%-28wt.%, for example, 20wt.%, 22wt.%, 24wt.%, 26wt.%, or 28wt.%.

[0020] In this invention, the mass fraction of MgO is 6wt.%-12wt.%, for example, 6wt.%, 8wt.%, 10wt.%, or 12wt.%.

[0021] In this invention, the mass fraction of Al2O3 is 25wt.%-28wt.%, for example, 25wt.%, 26wt.%, 27wt.%, or 28wt.%.

[0022] It should be noted that since the molybdenum tailings and the vanadium-titanium magnetite tailings contain effective components of synthetic cordierite, once the content of the above tailings is determined, the amount of SiO2, MgO and Al2O3 added can be calculated based on the molecular structure formula of cordierite.

[0023] Preferably, the total mass fraction of the molybdenum tailings and the vanadium-titanium magnetite tailings is ≤40%, for example, 40%, 30%, 20%, or 10%. If the content is too high, overheating may occur due to the influence of the fluxing components.

[0024] As a preferred technical solution for the cordierite-based far-infrared emitting ceramic composited with tailings described in this invention, the mass ratio of the molybdenum tailings to the vanadium-titanium magnetite tailings is 1:(1.2-5), for example, 1:1.5, 1:2, 1:2.5, 1:3, 1:3.5, 1:4, 1:4.5, or 1:5. When molybdenum tailings and vanadium-titanium magnetite tailings are used simultaneously, and their mass ratio is within the above range, the molecular structure of cordierite can be better controlled, resulting in far-infrared emitting ceramics with superior overall performance.

[0025] In a second aspect, the present invention provides a method for preparing cordierite-based far-infrared emitting ceramics composited with tailings as described in the first aspect, the method comprising the following steps:

[0026] (1) The tailings are ball-milled and mixed to obtain tailings material;

[0027] (2) The tailings material is mixed with other raw material components to obtain ceramic material;

[0028] (3) The ceramic material is shaped and sintered to obtain the tailings composite cordierite-based far-infrared emitting ceramic.

[0029] The present invention does not specifically limit the equipment used for ball milling; for example, it may be a planetary ball mill.

[0030] The method of this invention is simple and suitable for industrial production. Furthermore, since the tailings contain fluxing components, energy costs can be significantly reduced. The use of waste tailings as raw material to replace conventional chemical reagents further reduces production costs.

[0031] Preferably, the tailings in step (1) are obtained by drying the tailings sludge;

[0032] Preferably, the rotational speed of the ball mill in step (1) is 1000 r / min to 2000 r / min, such as 1000 r / min, 1200 r / min, 1300 r / min, 1500 r / min, 1600 r / min, 1700 r / min, 1800 r / min, 1900 r / min or 2000 r / min.

[0033] Preferably, the ball milling time in step (1) is 1h-3h, for example 1h, 1.5h, 2h, 2.5h or 3h.

[0034] Preferably, during the ball milling process in step (1), the material-to-ball ratio is 1:(1.5-3), such as 1:1.5, 1:2, 1:2.5 or 1:3.

[0035] Preferably, during the ball milling process in step (1), for molybdenum tailings, the particle size D50 of the material after ball milling is 5μm-8μm, such as 5μm, 6μm, 7μm or 8μm.

[0036] Preferably, in step (1), for vanadium-titanium magnetite tailings, the particle size D50 of the ball-milled material is 10μm-12μm, such as 10μm, 11μm or 12μm.

[0037] Preferably, after ball milling and mixing in step (1), the ball-milled material is sieved, and the undersized powder is collected. In one embodiment, the sieve used for sieving has a mesh size of 200.

[0038] Preferably, the mixing method in step (2) is ball milling, and the rotation speed of the ball mill is 800 r / min-1200 r / min, such as 800 r / min, 900 r / min, 1000 r / min, 1100 r / min or 1200 r / min; the ball milling time is 20 min-50 min, such as 20 min, 30 min, 40 min or 50 min.

[0039] Preferably, in step (2), after ball milling, the milled material is sieved to collect the undersized powder. In one embodiment, the sieve used for sieving has a mesh size of 200.

[0040] Preferably, the molding pressure in step (3) is 15MPa-25MPa, such as 15MPa, 16MPa, 17MPa, 18MPa, 19MPa, 20MPa, 21MPa, 22MPa, 23MPa, 24MPa, or 25MPa. Increasing the molding pressure can improve the density of the ceramic, thereby enhancing its strength.

[0041] In one embodiment, during the molding process, the mass of powder weighed each time is 2.5g, and the resulting ceramic body has dimensions of 40mm × 6mm × 4mm.

[0042] Preferably, the sintering pressure in step (3) is atmospheric pressure.

[0043] Preferably, the sintering temperature in step (3) is 1160℃~1200℃, for example, 1160℃, 1170℃, 1180℃, 1190℃ or 1200℃.

[0044] Preferably, in step (3), the holding time at the sintering temperature is 1h-3h, for example 1h, 1.5h, 2h, 2.5h or 3h.

[0045] Preferably, in the sintering process described in step (3), the temperature is first raised from room temperature to 1000°C, and then further raised to the sintering temperature.

[0046] Preferably, the heating rate from room temperature to 1000°C is 5°C / min to 7°C / min, for example, 5°C / min, 6°C / min or 7°C / min.

[0047] Preferably, the heating rate is 1℃ / min-3℃ / min, for example, 1℃ / min, 2℃ / min or 3℃ / min.

[0048] In this invention, the heating rate during sintering should not be too fast, otherwise cracks may be generated.

[0049] In one embodiment, the cooling process after sintering is as follows: cooling to room temperature with the furnace.

[0050] The present invention does not limit the sintering equipment, such as a muffle furnace.

[0051] As a preferred technical solution for the preparation method of the tailings composite cordierite-based far-infrared emitting ceramic of the present invention, the preparation method includes the following steps:

[0052] (1) First, molybdenum tailings and vanadium-titanium magnetite tailings are fed into a planetary ball mill and milled at a speed of 1000r / min-2000r / min for 1h-3h. The mass ratio of tailings to zirconium oxide balls is 1:(1.5-3). The tailings after ball milling are screened to 200 mesh.

[0053] (2) According to the formula amount of far-infrared emitting ceramic, the corresponding mass of tailings and other raw material components are mixed in a ball mill at a speed of 800r / min-1200r / min for 20min-50min, and then sieved through a 200-mesh sieve to obtain uniformly mixed ceramic powder.

[0054] (3) Place the ceramic powder into a mold and dry press it into a ceramic body under a pressure of 15MPa-25MPa;

[0055] (4) Finally, the tailings composite cordierite-based far-infrared emitting ceramics were sintered at atmospheric pressure in a muffle furnace to obtain tailings composite cordierite-based far-infrared emitting ceramics.

[0056] The atmospheric pressure sintering process includes: first heating from room temperature to 1000℃ at a heating rate of 5℃ / min-7℃ / min, and then heating to 1160℃~1200℃ at a heating rate of 1℃ / min-3℃ / min, and holding at that temperature for 1h-3h.

[0057] Thirdly, the present invention provides a use of the tailings composite cordierite-based far-infrared emitting ceramic as described in the first aspect, wherein the tailings composite cordierite-based far-infrared emitting ceramic is used as a heating element.

[0058] The numerical range described in this invention includes not only the point values ​​listed above, but also any point values ​​within the numerical ranges not listed above. Due to space limitations and for the sake of brevity, this invention will not exhaustively list all the specific point values ​​included in the range.

[0059] Compared with existing technologies, the present invention has the following beneficial effects:

[0060] (1) This invention uses inexpensive and readily available tailings as one of the main components, and combines them with silicon dioxide, magnesium oxide and aluminum oxide to regulate the crystal molecular formula of cordierite. Some transition metal ions in vanadium-titanium magnetite tailings and / or molybdenum tailings react with Mg 2+With similar radii, they can easily enter the crystal structure and replace the Mg atoms therein. 2+ This leads to lattice distortion and defects, resulting in a decrease in ion vibration symmetry. This allows for the coexistence of polycrystalline phases within the ceramic, improving the infrared emissivity and mechanical properties of cordierite. Its far-infrared emissivity in the 8μm-14μm range can reach over 0.867, and its flexural strength can reach over 49.2MPa. By optimizing the types and amounts of minerals in the raw materials, the far-infrared emissivity in the 8μm-14μm range can reach over 0.95, and the flexural strength can reach over 67MPa.

[0061] (2) This invention reuses accumulated tailings resources, turning waste into treasure and reducing preparation costs. Moreover, since vanadium-titanium magnetite tailings contain fluxing components (such as K2O and Na2O), the sintering temperature can be significantly reduced. This invention can obtain high-performance far-infrared emitting ceramics at a lower sintering temperature, greatly reducing production energy consumption. The preparation process of this invention is simple, the production cost is low, and it is suitable for industrial production. Attached Figure Description

[0062] Figure 1 The XRD patterns of the cordierite-based far-infrared emitting ceramics composited with tailings from Examples 1-4 are shown.

[0063] Figure 2 The XRD pattern of the cordierite-based far-infrared emitting ceramic composite of tailings in Example 6 is shown.

[0064] Figure 3 The XRD pattern of the cordierite-based far-infrared emitting ceramic in Comparative Example 1 is shown.

[0065] Figure 4 SEM images of the fracture surfaces of the cordierite-based far-infrared emitting ceramics composited with tailings from Examples 1-4.

[0066] Figure 5 This is a SEM image of the fracture surface of the cordierite-based far-infrared emitting ceramic composite of tailings in Example 6.

[0067] Figure 6 This is a SEM image of the fracture surface of the cordierite-based far-infrared emitting ceramic of Comparative Example 1. Detailed Implementation

[0068] The technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0069] The specific embodiments described herein are for illustrative purposes only and are not intended to limit the scope of the invention.

[0070] In this embodiment of the invention, the main components of molybdenum tailings are shown in Table 1, and the main components of vanadium-titanium magnetite tailings are shown in Table 2.

[0071] Table 1. Chemical composition of molybdenum tailings (wt.%)

[0072]

[0073] Table 2 Chemical composition (wt.%) of vanadium-titanium magnetite tailings

[0074]

[0075] In Tables 1 and 2 above, LOI refers to loss on ignition.

[0076] Example 1

[0077] This embodiment provides a method for preparing cordierite-based far-infrared emitting ceramics composited with tailings, the preparation method comprising the following steps:

[0078] (1) First, the molybdenum tailings and vanadium-titanium magnetite tailings were fed into a planetary ball mill and milled at a speed of 1500 r / min for 2 hours. The mass ratio of tailings to zirconium oxide balls was 1:1.5. The tailings after ball milling were screened to 200 mesh. The particle size D50 of the molybdenum tailings after ball milling was 6 μm, and the particle size D50 of the vanadium-titanium magnetite tailings after ball milling was 11 μm.

[0079] (2) Then, according to the far-infrared emitting ceramic formula, the corresponding mass of tailings and pure chemical reagents were weighed separately, and mixed in a ball mill at a speed of 1000 r / min for 30 min. After passing through a 200 mesh sieve, uniformly mixed ceramic powder was obtained. The far-infrared emitting ceramic formula is as follows:

[0080]

[0081] (3) Place the ceramic powder into a mold and dry press it with a pressure of 20MPa to form a ceramic body of 40mm×6mm×4mm.

[0082] (4) Finally, the tailings composite cordierite-based far-infrared emitting ceramics were sintered at atmospheric pressure in a muffle furnace to obtain tailings composite cordierite-based far-infrared emitting ceramics.

[0083] The atmospheric pressure sintering process includes: first heating from room temperature to 1000℃ at a heating rate of 5℃ / min, then heating to 1180℃ at a heating rate of 3℃ / min and holding at the highest temperature for 2 hours, and then cooling with the furnace to obtain a cordierite-based far-infrared emitting ceramic composited with tailings, denoted as C1.

[0084] Example 2

[0085] This embodiment provides a method for preparing cordierite-based far-infrared emitting ceramics composited with tailings. The difference from Embodiment 1 lies only in the far-infrared emitting ceramic formulation. The far-infrared emitting ceramic formulation in this embodiment is as follows:

[0086]

[0087]

[0088] The tailings composite cordierite-based far-infrared emitting ceramic prepared in this embodiment is designated as C2.

[0089] Example 3

[0090] This embodiment provides a method for preparing cordierite-based far-infrared emitting ceramics composited with tailings. The only difference from Embodiment 1 is the maximum sintering temperature (1200℃) and the far-infrared emitting ceramic formula. The far-infrared emitting ceramic formula in this embodiment is as follows:

[0091]

[0092] The tailings composite cordierite-based far-infrared emitting ceramic prepared in this embodiment is designated as C3.

[0093] Example 4

[0094] This embodiment provides a method for preparing cordierite-based far-infrared emitting ceramics composited with tailings. The only difference from Embodiment 1 is the maximum sintering temperature (1200℃) and the far-infrared emitting ceramic formula. The far-infrared emitting ceramic formula in this embodiment is as follows:

[0095]

[0096] The tailings composite cordierite-based far-infrared emitting ceramic prepared in this embodiment is designated as C4.

[0097] It should be noted that in Examples 1-4 of the present invention, since the ratio of molybdenum tailings and vanadium-titanium magnetite tailings has changed, in order to obtain ceramic materials with cordierite structure, it is necessary to adaptively adjust the content of SiO2, MgO and Al2O3 in the formula. At the same time, the optimal sintering temperature is different for different formulas, so the sintering temperature has been adaptively adjusted.

[0098] Example 5

[0099] This embodiment provides a method for preparing cordierite-based far-infrared emitting ceramics composited with tailings, including the following steps:

[0100] (1) First, molybdenum tailings and vanadium-titanium magnetite tailings are fed into a planetary ball mill and ball-milled at a speed of 2000 r / min for 1 h. The mass ratio of tailings to zirconium oxide balls is 1:2. The tailings after ball milling are screened at 200 mesh. The particle size D50 of the molybdenum tailings after ball milling is 5 μm, and the particle size D50 of the vanadium-titanium magnetite tailings after ball milling is 10 μm.

[0101] (2) Then, according to the far-infrared emitting ceramic formula, the corresponding mass of tailings and pure chemical reagents were weighed separately, and mixed in a ball mill at a speed of 800 r / min for 50 min. After passing through a 200-mesh sieve, uniformly mixed ceramic powder was obtained. The far-infrared emitting ceramic formula is as follows:

[0102]

[0103] (3) Place the ceramic powder into a mold and dry press it with a pressure of 17MPa to form a ceramic body of 40mm×6mm×4mm.

[0104] (4) Finally, the tailings composite cordierite-based far-infrared emitting ceramics were sintered at atmospheric pressure in a muffle furnace to obtain tailings composite cordierite-based far-infrared emitting ceramics.

[0105] The atmospheric pressure sintering process includes: first heating from room temperature to 1000℃ at a heating rate of 6℃ / min, then heating to 1160℃ at a heating rate of 2℃ / min and holding at the highest temperature for 3 hours, and then cooling with the furnace to obtain a cordierite-based far-infrared emitting ceramic composited with tailings, denoted as C5.

[0106] Example 6

[0107] This embodiment provides a method for preparing cordierite-based far-infrared emitting ceramics composite with tailings. The difference from Embodiment 1 is that molybdenum tailings and vanadium-titanium magnetite tailings are replaced with pure molybdenum tailings, with a content of 40 wt.%.

[0108] The far-infrared emitting ceramic formula is as follows:

[0109]

[0110] The ceramic prepared in this comparative example is designated as C6.

[0111] Comparative Example 1

[0112] This comparative example provides a method for preparing cordierite-based far-infrared emitting ceramics. The difference from Example 1 is that the raw materials for far-infrared emitting ceramics do not contain tailings.

[0113] The far-infrared emitting ceramic formula is as follows:

[0114] SiO2 51.4 wt.%

[0115] MgO 13.7 wt.%

[0116] Al2O3 34.9 wt.%.

[0117] The ceramic prepared in this comparative example is denoted as D1.

[0118] Performance testing:

[0119] (1) XRD tests were performed on the cordierite-based far-infrared emitting ceramics composited with tailings in Examples 1-4, and SEM tests were performed on the fracture surface of the cordierite-based far-infrared emitting ceramics composited with tailings.

[0120] Figure 1 The XRD patterns of the cordierite-based far-infrared emitting ceramics composited with tailings from Examples 1-4 are shown. As can be seen from the figures, cordierite peaks appear in samples C1 and C2, but with low intensity. In contrast, the cordierite peak intensity is higher in samples C3 and C4 at 1200℃, indicating that the crystallinity of cordierite is higher than that of C1 and C2 at this temperature. This is because the higher sintering temperature of C3 and C4 promotes the crystallization of the cordierite phase. Alumina peaks appear in samples C1 and C2, while the alumina peaks disappear in C3 and C4. Furthermore, the peak intensities of quartz at 26.6° and magnesium aluminum spinel at 31.1° are significantly lower than those of C1 and C2. This is because magnesium aluminum spinel reacts with quartz to form cordierite, hence the higher cordierite peak intensity in C3 and C4. Samples C3 and C4 formed an iron-containing cordierite phase [(Mg...] at 1200℃. 0.57 Fe 0.43 )2Al4Si5O 18 This is because cordierite itself has a loose crystal structure, and Mg... 2+ The radius (r = 0.066 nm) and Fe 3+ (r=0.0645nm) are close, and their radius difference is ≤15%. According to the Hume-Rothery rule, when the radius difference between two ions is ≤15%, a substitution solid solution is easily formed. Therefore, Mg... 2+ Easily affected by transition metal ions Fe 3+ The substitution of iron with iron results in the formation of an iron-containing substitutional solid solution. The ion substitution leads to changes in lattice parameters, which greatly affects the far-infrared emission performance of the ceramic.

[0121] Figure 2 The image shows the XRD pattern of the cordierite-based far-infrared emitting ceramic composite from tailings in Example 6. As can be seen from the image, sample C6 shows peaks for cordierite, as well as peaks for quartz, spinel, and corundum.

[0122] Figure 3 The figure shows the XRD pattern of the cordierite-based far-infrared emitting ceramic of Comparative Example 1. As can be seen from the figure, sample D1 shows peaks of cordierite, as well as peaks of quartz and gold crystal.

[0123] Figure 4 These are SEM images of the fracture surfaces of the cordierite-based far-infrared emitting ceramics composited with tailings from Examples 1-4. Figure 4 (a) corresponds to Example 1, (b) corresponds to Example 2, (c) corresponds to Example 3, and (d) corresponds to Example 4. As can be seen from the figure, the cross-sections of C1-C4 are relatively flat and dense.

[0124] Figure 5 The image shows the SEM image of the fracture surface of the cordierite-based far-infrared emitting ceramic composite of tailings in Example 6. As can be seen from the image, its end face is relatively flat and dense.

[0125] Figure 6 The image shows a SEM image of the fracture surface of the cordierite-based far-infrared emitting ceramic of Comparative Example 1. As can be seen from the image, its end face is uneven and its structure is loose.

[0126] (2) Water absorption rate test: The water absorption rate of the ceramic sample was tested using an electronic balance in accordance with the ASTM C373-88 (2006) standard.

[0127] (3) Sintering shrinkage test: The linear shrinkage rate can be calculated by measuring the length L0 before sintering and the length L after sintering of the ceramic test strip, in mm, and using the following formula: λ=(L0-L) / L0×100%. Where λ is the linear shrinkage rate of the test strip; L0 is the length of the test strip before sintering; and L is the length of the test strip after sintering.

[0128] (4) Flexural strength test: The flexural strength of the sintered ceramic samples was tested on the Shenzhen Xin Sansi CMT-6140 universal testing machine by means of the three-point bending method in accordance with the GB / T6569-2006 standard.

[0129] (5) Far-infrared emissivity test: The far-infrared emissivity of the sample in the wavenumber range of 713-1250 cm⁻¹ was measured using a BRUKER-V80 Fourier transform infrared spectrometer from BRUKER GmbH, Germany. The calculation formula is as follows:

[0130] w = (V4 - V2) / (V3 - V1)

[0131] In the formula, w is the infrared emissivity of the sample in the wavenumber range of 8μm-14μm, V1 and V3 are the infrared emission spectra of the blackbody at 80℃ and 120℃, respectively, and V2 and V4 are the infrared emission spectra of the sample at 80℃ and 120℃, respectively.

[0132] The ceramics of Examples 1-7 and Comparative Example 1 were subjected to the tests described in (2)-(5) above. The test results are shown in Table 1.

[0133] Table 1

[0134]

[0135] As shown in Table 1, the far-infrared emitting ceramics prepared by this invention using tailings exhibit high far-infrared emissivity, high flexural strength, high bulk density, low shrinkage, and low water absorption. Furthermore, the preparation method is simple, requires low raw materials and low energy consumption, significantly reducing production costs and making it suitable for industrial production.

[0136] A comparison of Examples 1 and Examples 1-5 shows that, compared to using only vanadium-titanium magnetite tailings (sample C4 in Example 4), under the same total mineral usage, adjusting the mass ratio of molybdenum tailings to vanadium-titanium magnetite tailings within the range of 1:(1.2-5) can achieve a synergistic effect, which is more conducive to improving the performance of the prepared cordierite-based far-infrared emitting ceramics, resulting in better performance of the prepared far-infrared emitting ceramics.

[0137] By comparing Examples 1-6 with Comparative Example 1, it can be seen that the present invention uses tailings to prepare cordierite-based far-infrared emitting ceramics, which can not only reduce the cost of raw materials and sintering costs, but also improve far-infrared emission performance.

[0138] The applicant declares that the detailed method of the present invention is illustrated by the above embodiments, but the present invention is not limited to the above detailed method, that is, it does not mean that the present invention must rely on the above detailed method to be implemented. Those skilled in the art should understand that any improvements to the present invention, equivalent substitutions of the raw materials of the product of the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A tailings-composite cordierite-based far infrared-emitting ceramic, characterized in that, The tailings-composite chlorite-based far-infrared emitting ceramic raw material components include tailings, SiO2, MgO and Al2O3; The tailings include vanadium-titanium magnetite tailings and molybdenum tailings; The vanadium-titanium magnetite tailings and molybdenum tailings contain fluxing components; The mass ratio of the molybdenum tailings to the vanadium-titanium magnetite tailings is 1:(1.2-5); The mass fraction of each component is: Molybdenum tailings 0-30wt.% Vanadium-titanium magnetite tailings 0-40wt.% SiO2 20wt.%-28wt.% MgO 6wt.%-12wt.% Al2O3 25wt.%-28wt.%.

2. The tailings-composite cordierite-based far infrared-emitting ceramic according to claim 1, characterized in that The total mass fraction of the molybdenum tailings and the vanadium-titanium magnetite tailings is ≤40%.

3. A method for preparing a tailings-composite cordierite-based far infrared- emitting ceramic according to any one of claims 1-2, characterized in that, The preparation method comprises the following steps: (1) Ball-milling the tailings to obtain tailings material; (2) Mixing the tailings material with other raw material components to obtain ceramic material; (3) Forming and sintering the ceramic material to obtain the tailings-composite chlorite-based far-infrared emitting ceramic.

4. The production method according to claim 3, characterized by, In step (1), the tailings are obtained by drying tailings sludge.

5. The preparation method according to claim 3, characterized in that, In step (1), the ball-milling speed is 1000r / min-2000r / min.

6. The preparation method according to claim 3, characterized in that, In step (1), the ball-milling time is 1h-3h.

7. The preparation method according to claim 3, characterized in that, In step (1), the ball-milling process is carried out at a ball-to-material ratio of 1:(1.5-3).

8. The preparation method according to claim 3, characterized in that, In step (1), for molybdenum tailings, the particle size D50 of the ball-milled material is 5μm-8μm.

9. The production method according to claim 3, wherein In step (1), for vanadium-titanium magnetite tailings, the particle size D50 of the ball-milled material is 10μm-12μm.

10. The method of claim 3, wherein, In step (1), the ball-milled material is sieved, and the undersize powder is taken.

11. The preparation method according to claim 3, characterized in that, In step (2), the mixing is carried out by ball-milling at a speed of 800r / min-1200r / min for 20min-50min.

12. The method of claim 11, wherein, In step (2), the ball-milled material is sieved, and the undersize powder is taken.

13. The preparation method according to claim 3, characterized in that, In step (3), the forming pressure is 15MPa -25MPa.

14. The method of claim 3, wherein, In step (3), the sintering is carried out at normal pressure.

15. The preparation method according to claim 3, characterized in that, In step (3), the sintering temperature is 1160℃~1200℃.

16. The method of claim 15, wherein, In step (3), the sintering temperature is maintained for 1h-3h.

17. The preparation method according to claim 3, characterized in that, In step (3), the sintering process is carried out by first increasing the temperature from room temperature to 1000℃, and then further increasing the temperature to the sintering temperature.

18. The method of claim 17, wherein, The temperature increasing rate from room temperature to 1000℃ is 5℃ / min-7℃ / min.

19. The method of claim 17, wherein, The further temperature increasing rate is 1℃ / min-3℃ / min.

20. The method of claim 3, wherein, The preparation method comprises the following steps: (1) First, send the molybdenum tailings and vanadium-titanium magnetite tailings into a planetary ball mill, and ball-mill at a speed of 1000r / min-2000r / min for 1h-3h, with a mass ratio of tailings to zirconia balls of 1:(1.5-3), and sieve the ball-milled tailings to 200 mesh; (2) According to the formula amount of far infrared emission ceramic, the corresponding mass of tailings and other raw material components are mixed in a ball mill at a speed of 800r / min-1200r / min for 20min-50min, and then sieved through a 200 mesh screen to obtain a uniformly mixed ceramic powder; (3) The ceramic powder is placed in a mold and dry-pressed into a ceramic body under a pressure of 15MPa-25MPa; (4) Finally, the ceramic body is sintered at normal pressure in a muffle furnace to obtain a tailings-composite cordierite-based far infrared emission ceramic; The process of sintering at normal pressure includes: first, heating from room temperature to 1000℃ at a heating rate of 5℃ / min-7℃ / min, and then heating to 1160℃-1200℃ at a heating rate of 1℃ / min-3℃ / min, and maintaining the temperature for 1h-3h.

21. Use of a tailings-composite cordierite-based far infrared-emitting ceramic according to any one of claims 1 to 2, characterized in that The tailings-composite cordierite-based far infrared emission ceramic is used as a heat storage sheet.

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