La2o3-ceo2 doped bauxite based high density high wear resistant alumina porcelain ball and its preparation method

Abstract

The application discloses a La2O3-CeO2 doped bauxite-based high-density high-wear-resistance alumina porcelain ball and a preparation method thereof, and the raw material composition is 30-60 parts of titanium bauxite, 40-75 parts of alpha-Al2O3 micro powder, 5-10 parts of calcium carbonate and 2-10 parts of rare earth oxides; the rare earth oxides are La2O3 and CeO2, and the mass ratio of La2O3 to CeO2 is 1:1-2.5. The application takes titanium bauxite as a matrix, and introduces La2O3-CeO2 for common doping, so that the porcelain ball sintering can be realized at 1250-1350 DEG C, the sintering temperature is greatly reduced, the La-Ce-Ti-Ca-Si composite glass melt formed can refine the alumina grain size in the ceramic ball, and the multi-phase microcrystal is precipitated on the surface of the alumina grain, the neck connection between the particles is strengthened, the production cost is reduced, and the high-density high-wear-resistance alumina ceramic ball is obtained.

Description

Technical Field

[0001] This invention relates to the field of ceramic grinding media materials technology, and in particular to a La2O3-CeO2 doped bauxite-based high-density, high-wear-resistant alumina ceramic ball and its preparation method. Background Technology

[0002] Alumina wear-resistant ceramic balls, due to their high strength, high hardness, and wear resistance, are widely used as grinding media in industrial production. High-density alumina wear-resistant ceramic balls can significantly improve grinding efficiency and reduce energy consumption costs. To obtain high-density alumina wear-resistant ceramic balls, the alumina content is generally required to be between 80 and 99 wt%. However, since alumina is difficult to sinter at low temperatures, a certain amount of low-temperature flux is introduced into the alumina material to promote the densification process. However, contradictorily, the glassy phase formed by the low-temperature flux has physical properties such as fracture toughness and flexural strength that are far lower than those of Al2O3 crystals. Furthermore, during the sintering process, excessive liquid phase can induce abnormal growth of Al2O3 crystals, leading to a decrease in wear resistance.

[0003] To address the aforementioned problems, existing technology provides a high-iron-content wear-resistant ceramic ball. This involves introducing 20-40 wt% iron oxide into the ceramic ball, combining it with a potassium, calcium, magnesium, barium, aluminum, and silicon multi-component glass phase system. A pre-oxidation followed by reduction firing method is used to control the formation of a spinel phase between γ-Al₂O₃ and the iron oxide, potassium, calcium, magnesium, barium, aluminum, and silicon multi-component glass, thereby improving hardness and wear resistance, and lowering the sintering temperature of the ceramic ball. However, a drawback of this technology is that although iron oxide has a high density (5.1-5.2 g / cm³), it still has some limitations. 3 However, Fe 3+ During the sintering process, it can enter the glass phase and spinel to form a strong coloring effect. However, it can contaminate the object being ground during long-term use, especially in industries such as daily-use porcelain, special ceramics, and papermaking where high whiteness of the products is required. In addition, this technology uses γ-Al2O3 as the main source of alumina, and the main phase formed in the end is the spinel phase, which has a much lower hardness than alumina ceramic balls dominated by corundum phase.

[0004] Another widely adopted approach in existing technologies is to add multiphase oxides to alumina ceramic spheres, such as ZrSiO4 (4.7 g / cm³), which has a higher bulk density. 3 ) and t-ZrO2 (6.1 g / cm) 3Adding Al2O3 to alumina ceramic materials forms composite ceramic materials. Multiple grain boundaries mutually inhibit grain regrowth, and multiphase rare earth oxides synergistically promote sintering with calcium magnesium aluminum silicate liquid phase (CMAS). However, this method has a drawback: Al2O3 and ZrO2 are almost non-eutectic. The ceramic spheres can only rely on the CMAS liquid phase to drive the sintering process. Therefore, when the ZrO2 content is high, it actually inhibits the ceramic sintering process, reduces the degree of interparticle bonding, and adversely affects the density and strength of the material. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of existing technologies and provide a La2O3-CeO2-doped bauxite-based high-density, high-wear-resistant alumina ceramic ball. Using titanium aluminate as the matrix, La2O3-CeO2 is introduced for co-doping, forming a La-Ce-Ti-Ca-Si composite low-temperature eutectic. The ceramic ball is sintered at 1250–1350℃, significantly reducing production costs while obtaining high-density, wear-resistant alumina ceramic balls. Another objective of this invention is to provide a method and product for preparing the aforementioned La2O3-CeO2-doped bauxite-based high-density, high-wear-resistant alumina ceramic ball.

[0006] The objective of this invention is achieved through the following technical solution:

[0007] This invention provides a La2O3-CeO2-doped bauxite-based high-density, high-wear-resistant alumina ceramic ball. Its raw material composition, by weight, consists of 30-60 parts of titanium aluminate, 40-75 parts of α-Al2O3 micro powder, 5-10 parts of calcium carbonate, and 2-10 parts of rare earth oxides. The rare earth oxides are La2O3 and CeO2, with a mass ratio of La2O3:CeO2 = 1:1-2.5. The ceramic balls are sintered at 1250-1350℃, resulting in alumina ceramic balls with a specific gravity of 3.5-3.8 g / cm³. 3 The wear resistance coefficient is 1.7~1.8g / kg / h.

[0008] Furthermore, the chemical composition of the titanium aluminate of the present invention is 65-80 wt% Al2O3, 5-15 wt% SiO2, 0.5-3 wt% Fe2O3, 1-5.5 wt% TiO2, 1.5-5.5 wt% RO+R2O, and 10-12 wt% IL.

[0009] Another objective of this invention is achieved through the following technical solution:

[0010] The method for preparing the La2O3-CeO2-doped bauxite-based high-density, high-wear-resistant alumina ceramic balls provided by the present invention includes the following steps:

[0011] (1) The titanium aluminate bauxite is placed in a two-stage ball mill for pre-grinding treatment, that is, first-stage ball milling is performed to obtain coarse abrasive, and then the coarse abrasive is subjected to second-stage ball milling to obtain pre-ground titanium aluminate bauxite.

[0012] (2) After mixing the pre-ground titanium aluminate bauxite slurry with other raw materials according to the ratio, the mixture is ball-milled in a sand mill for 20-35 hours according to the mass ratio of raw materials:balls:water = 1:1.2-2.5:0.5-1 to obtain the mixed slurry;

[0013] (3) The mixed slurry is spray granulated, rolled and dried, and then fired at 1250-1350℃ for 30-120 minutes to obtain alumina ceramic balls.

[0014] In the above scheme, the particle size of the coarse abrasive in step (1) of the preparation method of the present invention is D50 < 10 μm, and the particle size of the pre-ground titanium aluminate is D50 < 3 μm. The particle size of the mixed slurry in step (2) is D50 < 1 μm.

[0015] The product prepared by the above-mentioned method for preparing La2O3-CeO2-doped bauxite-based high-density, high-wear-resistant alumina ceramic balls has the following chemical composition: Al2O3 80-90 wt%, SiO2 2-5 wt%, Fe2O3 0.1-1 wt%, TiO2 0.5-2 wt%, RO+R2O 2-6 wt%, La2O3 2-3 wt%, and CeO2 3-7 wt%.

[0016] The present invention has the following beneficial effects:

[0017] (1) The present invention uses titanium aluminate as the matrix. Titanium aluminate contains a certain amount of TiO2 and SiO2. During the firing process, it forms a La-Ce-Ti-Ca-Si composite low-temperature eutectic with calcium carbonate, La2O3 and CeO2, which rapidly wets Al2O3 particles and penetrates into the particle gaps, significantly reducing the firing temperature of alumina ceramic balls, promoting the sintering process of the green body, and increasing the bulk density of alumina ceramic balls.

[0018] (2) The La-Ce-Ti-Ca-Si composite low-temperature eutectic formed by this invention differs from the liquid phase (CMAS) in conventional alumina ceramic materials because La 3+ With Ce 4+ Ionic radius greater than Si 4+ The La-Ce-Ti-Ca-Si glass melt has a stable network structure, which inhibits the mass transfer process of high-valence ions in the glass melt, resulting in the slow growth of Al2O3, more uniform grain size, and refinement of the alumina grain size in the ceramic balls, forming a fine-grained microstructure, which is beneficial to improving the wear resistance of the ceramic balls.

[0019] (3) The La-Ce-Ti-Ca-Si composite eutectic of the present invention can change the phase composition at the neck connection between alumina particles. 4+ With Ti 4+ Both are variable valence oxides, with ionic radii similar to Al. 3+ The difference is significant, therefore it can only enter the Al2O3 lattice to form a limited solid solution, while Ca in the glass melt... 2+ Si 4+ The combined effect of these factors causes the segregation of microcrystals such as CaAl2TiO5, CaAl2Si2O8, and CeAlO3 on the surface of Al2O3 crystals. This strengthens the neck connections between Al2O3 particles, further improving the wear resistance and compressive strength of the alumina ceramic balls.

[0020] (4) The titanium aluminate used in this invention has a wide range of sources. The two-stage ball milling process for pretreatment of the aluminate followed by sand milling with other raw materials improves the reactivity of the aluminate particles. The resulting high-density, high-wear-resistant alumina ceramic balls have an Al2O3 content of 80-90 wt%, which significantly reduces production costs. The processing and procurement costs are also much lower than those of using single α-Al2O3 ceramic balls and aluminum-zirconium composite ceramic balls.

[0021] The present invention will now be described in further detail with reference to embodiments. Detailed Implementation

[0022] This invention relates to a La2O3-CeO2 doped bauxite-based high-density, high-wear-resistant alumina ceramic ball, the raw material composition of which is shown in Table 1.

[0023] Table 1. Raw material composition of La2O3-CeO2 doped bauxite-based high-density, high-wear-resistant alumina ceramic balls in the embodiments of the present invention.

[0024]

[0025] The chemical composition of titanium aluminate is shown in Table 2.

[0026] Table 2. Chemical composition (wt%) of titanium aluminate in the embodiments of the present invention.

[0027]

[0028] R2O represents alkali metal oxides, and RO represents alkaline earth metal oxides.

[0029] This invention discloses a method for preparing La2O3-CeO2-doped bauxite-based high-density, high-wear-resistant alumina ceramic balls, the steps of which are as follows:

[0030] (1) The above titanium aluminate was placed in a two-stage ball mill for pre-grinding treatment. That is, first-stage coarse grinding was carried out to obtain coarse grinding material with a particle size of D50 < 10 μm. After sieving, the coarse grinding material was subjected to second-stage fine grinding to obtain pre-ground titanium aluminate with a particle size of D50 < 3 μm.

[0031] (2) After mixing the above pre-ground titanium aluminate bauxite slurry with other raw materials according to the ratio, the mixture is ball-milled in a sand mill for 20-35 hours according to the mass ratio of raw materials:balls:water = 1:1.2-2.5:0.5-1 to obtain a mixed slurry with a particle size of D50 < 1 μm.

[0032] (3) After spray granulation, rolling molding and drying, the above mixed slurry is fired at 1250-1350℃ and held for 30-120 minutes to obtain alumina ceramic balls.

[0033] The preparation method and process parameters are shown in Table 3.

[0034] Table 3 Process parameters of the preparation method in the embodiments of the present invention

[0035]

[0036] The chemical composition of the alumina ceramic balls prepared in the various embodiments of the present invention is shown in Table 4, and the performance indicators are shown in Table 5.

[0037] Table 4. Chemical composition (wt%) of the alumina ceramic balls prepared in each embodiment of the present invention.

[0038]

[0039] Table 5 Performance indicators of alumina ceramic balls prepared in various embodiments of the present invention

[0040]

Claims

1. A method for preparing La2O3-CeO2-doped bauxite-based high-density, high-wear-resistant alumina ceramic balls, characterized in that: The alumina ceramic spheres are composed of the following raw materials by weight: 30-60 parts of titanium aluminate, 40-75 parts of α-Al₂O₃ micro powder, 5-10 parts of calcium carbonate, and 2-10 parts of rare earth oxides; the chemical composition of the titanium aluminate is: Al₂O₃ 65-80 wt%, SiO₂ 5-15 wt%, Fe₂O₃ 0.5-3 wt%, TiO₂ 1-5.5 wt%, RO+R₂O 1.5-5.5 wt%, and IL 10-12 wt%; the rare earth oxides are La₂O₃ and CeO₂, with a mass ratio of La₂O₃:CeO₂ = 1:1-2.5; the raw materials form a La-Ce-Ti-Ca-Si composite low-temperature eutectic during the firing process; the preparation method includes the following steps: (1) The titanium aluminate is placed in a two-stage ball mill for pre-grinding treatment. That is, first-stage ball milling is performed to obtain coarse abrasive with a particle size of D50 < 10 μm, and then the coarse abrasive is subjected to second-stage ball milling to obtain pre-ground titanium aluminate with a particle size of D50 < 3 μm. (2) After mixing the pre-ground titanium aluminate bauxite slurry with other raw materials according to the ratio, the mixture is ball-milled in a sand mill for 20-35 hours according to the mass ratio of raw materials:balls:water = 1:1.2-2.5:0.5-1 to obtain a mixed slurry with a particle size of D50 < 1 μm. (3) The mixed slurry is spray-granulated, rolled, and dried, then fired at 1250–1350℃ for 30–120 min to obtain alumina ceramic balls; the specific gravity of the obtained alumina ceramic balls is 3.5–3.8 g / cm³. 3 The wear resistance coefficient is 1.7-1.8 g / kg / h, and the chemical composition is Al2O3 80-90wt%, SiO2 2-5wt%, Fe2O3 0.1-1wt%, TiO2 0.5-2wt%, RO+R2O 2-6wt%, La2O3 2-3wt%, CeO2 3-7wt%.

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