A method for preparing high-strength building ceramic bodies by adding a calcium-magnesium sintering aid containing forsterite

Abstract

The application relates to a method for preparing high-strength building ceramic bodies by adding a calcium-magnesium sintering aid containing forsterite, and belongs to the technical field of building ceramic preparation, characterized by comprising the following steps: proportioning according to mass: 50% of kaolin, 20% of feldspar, 30% of quartz, 2.5% of barium carbonate, 0.5% of zinc oxide, 4% of glimmer, 2% of talc, 3% of forsterite and 0 or 2% of diopside, adding water, ball milling in a rapid ball mill, manually manufacturing material particles after drying the slurry, die forming, firing in a roller kiln at 1170 DEG C, and the firing cycle is 70 minutes, thereby obtaining the high-strength building ceramic bodies. The raw materials adopted in the technical scheme are cheap, the adding mode is simple, and the industrial production is easy. The added calcium-magnesium sintering aid containing forsterite serves as an auxiliary raw material, can optimize the crystal phase composition and microstructure of the building ceramic, and can improve the bending strength of the building ceramic, so as to meet the demand of high-load application places.

Description

Technical Field

[0001] A method for preparing high-strength building ceramic green bodies by adding a calcium-magnesium sintering aid containing magnesium olivine belongs to the field of building ceramic preparation technology. Background Technology

[0002] Compared to other decorative materials, architectural ceramics have advantages such as good decorative performance and strong weather resistance, making them significantly superior in interior and exterior wall decoration and floor decoration, and highly favored by consumers in the market. Traditional architectural ceramics use raw materials such as quartz, feldspar, and kaolinite, and are processed through mixing, ball milling, granulation, molding, and roller kiln firing, resulting in a short firing cycle and fast firing speed. The crystalline phase contains only a small amount of mullite phase and unmelted quartz phase. Partially molten quartz is prone to re-precipitate during cooling to form cristobalite. The difference in the coefficient of thermal expansion between the quartz phase and the glass phase leads to defects such as cracks, resulting in lower strength of architectural ceramics and affecting the performance of building decoration and finishing materials. Current methods for preparing high-strength architectural ceramics include adding fibers or second-phase particles for reinforcement, as well as pre-stressing the glaze layer.

[0003] The technical solution of Chinese invention patent 202211498023.0 is as follows: Utilizing the ratio of powder particle size and chemical composition, feldspar raw materials and silica raw materials are first ground to a median particle size of 3 to 6 micrometers, then clay raw materials, high-alumina raw materials, calcareous raw materials, and water-soluble glass strengthening components are mixed. Subsequently, all the mixed raw materials are ground to a median particle size of 8 to 12 micrometers. Under the action of grinding aids, physical-reactive composite reinforcing agents, and diluents, granules are obtained, which are then pressed and fired to obtain high-strength ceramic thin plates.

[0004] Chinese invention patent 202210503892.1 describes the use of ingredients with high silica content (74%~79%) to fire high-strength, high-silicon-content building ceramics.

[0005] Chinese invention patent 202211148742.X adds crystallization inducing agents and crystal growth promoters with specific particle size requirements, strictly controls the corresponding chemical composition and particle size requirements, and grows three-dimensional network mullite whiskers in situ under roller kiln firing conditions to produce high-toughness and high-strength building ceramic slab blanks.

[0006] As can be seen from the above, there is no reported method for improving the strength of building ceramics by adding calcium-magnesium sintering aids containing magnesium olivine during the batching process, regulating the crystallization behavior of building ceramics during firing, introducing multiple crystal phases to improve the microstructure of building ceramics, and optimizing the crack generation and propagation mechanism of building ceramics under load. Summary of the Invention

[0007] The purpose of this invention is to provide a method for preparing high-strength building ceramic green bodies by adding a calcium-magnesium sintering aid containing magnesium olivine, characterized by comprising the following steps:

[0008] (1) Prepare the ingredients according to the mass ratio: 50 kaolin, 20 feldspar, 30 quartz, 2.5 barium carbonate, 0.5 zinc oxide, 4 pyrophyllite, 2 talc, 3 forsterite, 0 or 2 diopside, add water to make the mass ratio of material to water 100:80, ball mill in a high-speed ball mill for 10 minutes, dry the slurry at 120°C, and manually produce the granules;

[0009] (2) The granules obtained in step (1) are placed into a mold and molded at 200 MPa to produce a green body of building ceramics;

[0010] (3) The building ceramic green body obtained in step (2) is placed in a roller kiln and fired at 1170°C for 70 minutes to produce a high-strength building ceramic green body.

[0011] In step (1), the mass percentages of each material are as follows: kaolin 44.64%, feldspar 17.86%, quartz 26.79%, barium carbonate 2.23%, zinc oxide 0.45%, pyrophyllite 3.57%, talc 1.79%, forsterite 2.68%, and diopside 0%; or kaolin 43.86%, feldspar 17.54%, quartz 26.32%, barium carbonate 2.19%, zinc oxide 0.44%, pyrophyllite 3.51%, talc 1.75%, forsterite 2.63%, and diopside 1.75%. Kaolin, feldspar, and quartz are used as the base materials for the green body, and their mass ratio is 50:20:30. Barium carbonate, zinc oxide, pyrophyllite, talc, forsterite, and diopside are used as sintering aids, and their mass ratio with kaolin is 2.5:0.5:4:2:3:0 or 2:50. The optimal mass ratio of diopside to kaolin is 2:50. In the process mentioned in step (3), the crystalline phase undergoes a crystal transformation when the high-strength building ceramic body cools down after firing, which leads to drastic changes in the volume of the body and the generation of microcracks. Barium carbonate decomposes into barium oxide, which works synergistically with zinc oxide to limit the drastic changes in firing volume and reduce the probability of crack formation. In the high-temperature firing process mentioned in step (3), pyrophyllite, talc, forsterite, and diopside can assist in the melting of silicate melt, which can both increase the shrinkage rate of the body and provide the basic elements for the formation of crystalline phases. In the rapid firing process of roller kiln production, quartz melts into silicate melt and reacts with aluminum, calcium, and magnesium elements to form a composite crystalline phase containing quartz, mullite, anorthite, and magnesium silicate, which changes the internal microstructure of the body and changes the way cracks are generated and propagated during the fracture process of the body under load, thus greatly improving the strength of the building ceramic body.

[0012] The beneficial effects of this invention are as follows:

[0013] 1. The raw materials used are inexpensive, the addition method is simple, and they are easy to industrialize.

[0014] 2. The added calcium-magnesium sintering aid containing magnesium olivine, as an auxiliary raw material, can optimize the crystal phase composition and microstructure of building ceramics, and improve the flexural strength of building ceramics to meet the needs of high-load application sites.

[0015] 3. The process flow of this technical solution is highly similar to that of traditional building ceramics, which is conducive to industrial production. Attached Figure Description

[0016] Appendix Figure 1 The X-ray diffraction (XRD) pattern of the high-strength building ceramic blank prepared in Example 1 is shown.

[0017] Appendix Figure 2 This is a scanning electron microscope (SEM) image of the high-strength building ceramic blank prepared in Example 1.

[0018] Appendix Figure 3 The X-ray diffraction (XRD) pattern of the high-strength building ceramic blank prepared in Example 2 is shown.

[0019] Appendix Figure 4 This is a scanning electron microscope (SEM) image of the high-strength building ceramic blank prepared in Example 2.

[0020] Appendix Figure 5 The X-ray diffraction (XRD) pattern of the building ceramic blank prepared in Example 1 is shown.

[0021] Appendix Figure 6 The image shows a scanning electron microscope (SEM) image of the building ceramic blank prepared in Example 1 for comparison. Detailed Implementation Example 1

[0022] (1) Prepare the following materials by mass ratio: 50 parts kaolin, 20 parts feldspar, 30 parts quartz, 2.5 parts barium carbonate, 0.5 parts zinc oxide, 4 parts pyrophyllite, 2 parts talc, and 3 parts magnesium olivine. Add water to make the mass ratio of material to water 100:80. Grind the material in a high-speed ball mill for 10 minutes. Then dry the slurry at 120°C and manually produce the granules.

[0023] (2) The granules obtained in step (1) are placed into a mold and molded at 200 MPa to produce a green body of building ceramics;

[0024] (3) The building ceramic green body obtained in step (2) is placed in a roller kiln and fired at 1170°C for 70 minutes to produce the building ceramic green body.

[0025] In step (1) of this embodiment, no diopside sintering aid was added to the ingredients. The average linear shrinkage rate of the building ceramic body obtained in step (3) was 13.46%. The building ceramic body obtained in step (3) was placed at a height of 1.4 meters and allowed to fall freely onto a tiled ground. This was recorded as one time. The test was repeated until the building ceramic body broke in half due to cracks extending from one side to the other side. This was recorded as the number of times it broke. Three building ceramic bodies were tested, and the number of times they broke were 14, 42, and 14, respectively. The flexural strength tested by the three-point bending test method was 42.71 MPa, 62.82 MPa, and 42.69 MPa.

[0026] Appendix Figure 1 The X-ray diffraction (XRD) pattern of the high-strength building ceramic body prepared in Example 1 is shown. Analysis revealed that the body contained: quartz phase (JCPDS card number 01-0649, corresponding to diffraction peaks at 2θ at 20.8050, 26.5597, 31.1257, 38.4305, 54.7953, 57.1436, and 67.9309º), mullite phase (JCPDS card number 74-2419, corresponding to diffraction peak at 2θ at 61.5601º), and anorthite phase (JCPDS card number 70-0287, corresponding to diffraction peaks at 2θ at 7.0127, 11.0918, and 49.9832º).

[0027] Appendix Figure 2 This is a scanning electron microscope (SEM) image of the high-strength architectural ceramic body prepared in Example 1. It exhibits low porosity, some interconnectedness of pores, a small number of microcracks, and a small amount of crystalline phase within the glassy phase of the fracture surface. This results in low surface smoothness, indicating that the cracks are deflected to some extent by the crystalline phase during propagation, thereby increasing the number of fractures and flexural strength. Example 2

[0028] (1) Prepare the following materials by mass ratio: 50 parts kaolin, 20 parts feldspar, 30 parts quartz, 2.5 parts barium carbonate, 0.5 parts zinc oxide, 4 parts pyrophyllite, 2 parts talc, 3 parts forsterite, and 2 parts diopside. Add water to make the mass ratio of material to water 100:80. After grinding in a high-speed ball mill for 10 minutes, dry the slurry at 120°C and manually produce the granules.

[0029] (2) The granules obtained in step (1) are placed into a mold and molded at 200 MPa to produce a high-strength building ceramic green body;

[0030] (3) The building ceramic green body obtained in step (2) is placed in a roller kiln and fired at 1170°C for 70 minutes to produce a high-strength building ceramic green body.

[0031] The high-strength building ceramic body obtained in step (3) had an average linear shrinkage rate of 14.18% after firing. The high-strength building ceramic body obtained in step (3) was placed at a height of 1.4 meters and allowed to fall freely onto a tiled ground. This was recorded as one fall. The test was repeated until the high-strength building ceramic body broke in two due to cracks extending from one side to the other side. This number of falls was recorded as the number of breaks. Three high-strength building ceramic bodies were tested, with 28, 50, and 43 breaks respectively. During the breakage process, the body with the highest number of breaks developed curved and uneven cracks. The flexural strength was tested using the three-point bending test method and found to be 50.31 MPa, 52.56 MPa, and 55.60 MPa, respectively.

[0032] Appendix Figure 3 The XRD pattern of the high-strength building ceramic body prepared in Example 2 is shown. Analysis revealed that the body contained: quartz phase (JCPDS card number 01-0649, corresponding to diffraction peaks at 2θ of 26.4489, 26.6792, 55.2052, and 59.7582º), mullite phase (JCPDS card number 74-2419, corresponding to diffraction peaks at 2θ of 54.0763 and 65.8199º), cristobalite phase (JCPDS card number 82-1404, corresponding to diffraction peaks at 2θ of 38.4545, 54.6397, 56.4226, and 65.1633º), and anorthite phase (JCPDS...). Card number 70-0287 corresponds to the diffraction peaks of 2θ at 13.8937, 18.6436, 22.3237, 35.8451, 42.2803 and 44.7336º) and magnesium silicate phase (JCPDS card number 87-2033 corresponds to the diffraction peak of 2θ at 51.1468º).

[0033] Appendix Figure 4 This is a scanning electron microscope (SEM) image of the high-strength architectural ceramic body prepared in Example 2. The low porosity and predominantly closed pores, along with the presence of numerous crystalline phases on the fracture surface, result in low surface smoothness. This indicates that the crack propagation process is deflected to some extent by the crystalline phases, leading to a significant increase in the number of fractures and flexural strength.

[0034] The selection and dosage of sintering aids in Examples 1 and 2 were determined through a long-term, repeated experimental process of adding aids. Only with the sintering aids mentioned in Examples 1 and 2 and the corresponding specific dosages can high-strength building ceramic green bodies with high flexural strength and low flexural strength dispersion be obtained. The main difference in the following comparative examples lies in the different sintering aids used. Taking the number of crushings and flexural strength of the building ceramics obtained in step (3) as the main reference, the influence of different sintering aids on the mechanical properties of building ceramic green bodies is explained. The main purpose is to illustrate that the improvement effect of different sintering aids and different dosages on the mechanical properties of building ceramics varies greatly.

[0035] Comparative Example 1

[0036] (1) Prepare the following materials by mass ratio: 50 parts kaolin, 20 parts feldspar, and 30 parts quartz. Add water to make the mass ratio of material to water 100:80. Grind the material in a high-speed ball mill for 10 minutes. Then dry the slurry at 120°C and manually produce the granules.

[0037] (2) The granules obtained in step (1) are placed into a mold and molded at 200 MPa to produce a green body of building ceramics;

[0038] (3) The building ceramic green body obtained in step (2) is placed in a roller kiln and fired at 1170°C for 70 minutes to produce the building ceramic green body.

[0039] In step (1) of this comparative example, the ingredients are the basic materials of traditional building ceramic body, without the addition of sintering aids. The average linear shrinkage rate of the building ceramic body obtained in step (3) is 13.83%. The building ceramic body obtained in step (3) is placed at a height of 1.4 meters and allowed to fall freely onto the tiled ground. This is recorded as one time. The test is repeated until the building ceramic body breaks in half due to cracks extending from one side to the other side. This number of times is recorded as the number of times. Three building ceramic bodies were tested, and the number of times they broke were 3, 13, and 13, respectively. The cracks produced by the body during the breaking process were relatively straight. The flexural strength tested by the three-point bending test method was 32.01 MPa, 46.34 MPa, and 48.96 MPa.

[0040] Appendix Figure 5The X-ray diffraction (XRD) pattern of the building ceramic body prepared in Example 1 is shown below. Analysis revealed that the body contains: quartz phase (JCPDS card number 01-0649, corresponding to diffraction peaks at 2θ of 20.9179, 26.7905, 50.2372, and 59.9189º), mullite phase (JCPDS card number 74-2419, corresponding to diffraction peaks at 2θ of 16.6873, 40.9034, 62.7503, 67.3446, and 68.0029º), and cristobalite phase (JCPDS card number 82-1404, corresponding to diffraction peak at 2θ of 43.4540º).

[0041] Appendix Figure 6 The image shows a scanning electron microscope (SEM) image of the ceramic building body prepared in Example 1 for comparison. The body exhibits high porosity, interconnected pores, numerous interconnected microcracks, and a smooth fracture surface, indicating that the cracks hardly deflect during propagation, resulting in a low number of fractures and low flexural strength.

[0042] Comparative Example 2

[0043] (1) Prepare the following materials by mass ratio: 50 parts kaolin, 20 parts feldspar, 30 parts quartz, 2.5 parts barium carbonate, 0.5 parts zinc oxide, 4 parts pyrophyllite, 2 parts talc, and 1.5 parts magnesium olivine. Add water to make the mass ratio of material to water 100:80. Grind the material in a high-speed ball mill for 10 minutes. Then dry the slurry at 120°C and manually produce the granules.

[0044] (2) The granules obtained in step (1) are placed into a mold and molded at 200 MPa to produce a green body of building ceramics;

[0045] (3) The building ceramic green body obtained in step (2) is placed in a roller kiln and fired at 1170°C for 70 minutes to produce the building ceramic green body.

[0046] In step (1) of this comparative example 2, no diopside sintering aid was added to the ingredients. The average linear shrinkage rate of the building ceramic body obtained in step (3) was 13.11%. The building ceramic body obtained in step (3) was placed at a height of 1.4 meters and allowed to fall freely onto a tiled ground. This was recorded as one fall. The test was repeated until the building ceramic body broke in half due to cracks extending from one side to the other side. This number of breaks was recorded as the number of breaks. Three building ceramic bodies were tested, and the number of breaks was 5, 22, and 10, respectively, which was relatively dispersed. The flexural strength tested by the three-point bending test method was 33.67 MPa, 49.22 MPa, and 38.53 MPa.

[0047] Comparative Example 3

[0048] (1) Prepare the following materials by mass ratio: 50 parts kaolin, 20 parts feldspar, 30 parts quartz, 2.5 parts barium carbonate, 0.5 parts zinc oxide, 4 parts pyrophyllite, 2 parts talc, and 4.5 parts magnesium olivine. Add water to make the mass ratio of material to water 100:80. Grind the material in a high-speed ball mill for 10 minutes. Then dry the slurry at 120°C and manually produce the granules.

[0049] (2) The granules obtained in step (1) are placed into a mold and molded at 200 MPa to produce a green body of building ceramics;

[0050] (3) The building ceramic green body obtained in step (2) is placed in a roller kiln and fired at 1170°C for 70 minutes to produce the building ceramic green body.

[0051] The ingredients mentioned in step (1) of this comparative example 3 did not include diopside sintering aid. The average linear shrinkage rate of the building ceramic body obtained in step (3) was 14.09%. The building ceramic body obtained in step (3) was placed at a height of 1.4 meters and allowed to fall freely onto a tiled ground. This was recorded as one time. The test was repeated until the building ceramic body broke in half due to cracks extending from one side to the other side. This was recorded as the number of times it broke. Three building ceramic bodies were tested, and the number of times they broke were 3, 1, and 42, respectively. The number of times they broke was too dispersed. The flexural strength tested by the three-point bending test method was 32.71 MPa, 62.82 MPa, and 30.69 MPa.

[0052] Comparative Example 4

[0053] (1) Prepare the following materials by mass ratio: 50 parts kaolin, 20 parts feldspar, 30 parts quartz, 2.5 parts barium carbonate, 0.5 parts zinc oxide, 4 parts pyrophyllite, 2 parts talc, and 6 parts magnesium olivine. Add water to make the mass ratio of material to water 100:80. Grind the material in a high-speed ball mill for 10 minutes. Then dry the slurry at 120°C and manually produce the granules.

[0054] (2) The granules obtained in step (1) are placed into a mold and molded at 200 MPa to produce a green body of building ceramics;

[0055] (3) The building ceramic green body obtained in step (2) is placed in a roller kiln and fired at 1170°C for 70 minutes to produce the building ceramic green body.

[0056] The ingredients mentioned in step (1) of this comparative example 4 did not include diopside sintering aid. The average linear shrinkage rate of the building ceramic body obtained in step (3) was 12.87%. The building ceramic body obtained in step (3) was placed at a height of 1.4 meters and allowed to fall freely onto a tiled ground. This was recorded as one fall. The test was repeated until the building ceramic body broke in half due to cracks extending from one side to the other side. This number of breaks was recorded. Three building ceramic bodies were tested, and the number of breaks was 2, 6, and 46, respectively, which was relatively dispersed. The flexural strength tested by the three-point bending test method was 31.52 MPa, 63.96 MPa, and 33.24 MPa.

[0057] Comparative Example 5

[0058] (1) Prepare the following materials by mass ratio: 50 parts kaolin, 20 parts feldspar, 30 parts quartz, 2.5 parts barium carbonate, 0.5 parts zinc oxide, 4 parts pyrophyllite, 2 parts talc, 3 parts forsterite, and 1 part diopside. Add water to make the mass ratio of material to water 100:80. Grind the material in a high-speed ball mill for 10 minutes. Then dry the slurry at 120°C and manually produce the granules.

[0059] (2) The granules obtained in step (1) are placed into a mold and molded at 200 MPa to produce a green body of building ceramics;

[0060] (3) The building ceramic green body obtained in step (2) is placed in a roller kiln and fired at 1170°C for 70 minutes to produce the building ceramic green body.

[0061] The small amount of diopside mentioned in step (1) of this comparative example 5 was added during the addition of sintering aids. The average linear shrinkage rate of the building ceramic body obtained in step (3) was 13.20%. The building ceramic body obtained in step (3) was placed at a height of 1.4 meters and allowed to fall freely onto the tiled ground. This was recorded as one time. The test was repeated until the building ceramic body broke in half due to cracks extending from one side to the other side. This was recorded as the number of times it broke. Three building ceramic bodies were tested, and the number of times they broke were 2, 2, and 4, respectively. The number of times they broke was low, and the cracks produced by the body during the breaking process were straight. The flexural strength tested by the three-point bending test method was 27.71 MPa, 28.82 MPa, and 31.69 MPa.

[0062] Comparative Example 6

[0063] (1) Prepare the following materials by mass ratio: 50 parts kaolin, 20 parts feldspar, 30 parts quartz, 2.5 parts barium carbonate, 0.5 parts zinc oxide, 4 parts pyrophyllite, 2 parts talc, 3 parts forsterite, and 4 parts diopside. Add water to make the mass ratio of material to water 100:80. Grind the material in a high-speed ball mill for 10 minutes. Then dry the slurry at 120°C and manually produce the granules.

[0064] (2) The granules obtained in step (1) are placed into a mold and molded at 200 MPa to produce a green body of building ceramics;

[0065] (3) The building ceramic green body obtained in step (2) is placed in a roller kiln and fired at 1170°C for 70 minutes to produce the building ceramic green body.

[0066] The small amount of diopside added during the addition of sintering aids mentioned in step (1) of this comparative example 6. The average linear shrinkage rate of the building ceramic body obtained in step (3) was 14.11%. The building ceramic body obtained in step (3) was placed at a height of 1.4 meters and allowed to fall freely onto the tiled ground, which was recorded as one time. The test was repeated until the building ceramic body broke in half due to cracks extending from one side to the other side. The number of times it broke was recorded. Three building ceramic bodies were tested, and the number of times they broke were 4, 5, and 37, respectively, which was relatively dispersed. The flexural strength tested by the three-point bending test method was 30.76 MPa, 33.95 MPa, and 52.78 MPa.

Claims

1. A method for the production of high-strength architectural ceramic bodies by adding a calcium-magnesium sintering aid containing forsterite, characterized in that Comprise the following steps: (1) according to the mass proportion of ingredients: kaolin 50, feldspar 20, quartz 30, barium carbonate 2.5, zinc oxide 0.5, 4, talc 2, magnesium olivine 3, diopside 0 or 2, namely the mass percentage of each material is: kaolin 44.64%, feldspar 17.86%, quartz 26.79%, barium carbonate 2.23%, zinc oxide 0.45%, 3.57% talc, 1.79% talc, magnesium olivine 2.68%; Or kaolin 43.86%, feldspar 17.54%, quartz 26.32%, barium carbonate 2.19%, zinc oxide 0.44%, 3.51% talc, 1.75% talc, magnesium olivine 2.63%, diopside 1.75%, add water, the mass ratio of material and water is 100:80, in the rapid ball mill, ball milling for 10 minutes, the slurry is dried at 120 DEG C, and the material particles are manually manufactured; (2) the material particles prepared by step (1) are put into the mold, and are formed by 200 MPa, to produce the building ceramic green body; (3) the building ceramic green body prepared by step (2) is placed in a roller kiln, and is fired at 1170 DEG C for 70 minutes, to produce the high-strength building ceramic body.

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