La2O3-CeO2 doped bauxite-based high-density high-wear-resistance alumina ceramic ball and preparation method thereof

Abstract

The invention discloses a La2O3-CeO2 doped bauxite-based high-density high-wear-resistance alumina ceramic ball and a preparation method thereof. The La2O3-CeO2 doped bauxite-based high-density high-wear-resistance alumina ceramic ball is prepared from the following raw materials in parts by weight: 30 to 60 parts of titanium bauxite, 40 to 75 parts of alpha-Al2O3 micro powder, 5 to 10 parts of calcium carbonate and 2 to 10 parts of rare earth oxide. The rare earth oxide is La2O3 and CeO2, and the mass ratio of La2O3 to CeO2 is 1: (1-2.5). According to the invention, titanium bauxite is used as a matrix, La2O3-CeO2 is introduced for co-doping, ceramic ball sintering is realized at 1250-1350 DEG C, the firing temperature is greatly reduced, the formed La-Ce-Ti-Ca-Si composite glass melt can refine the size of alumina crystal grains in ceramic balls, multiphase microcrystals are separated out on the surfaces of the alumina crystal grains, neck connection among particles is strengthened, and the performance of the ceramic balls is improved. And the high-density wear-resistant aluminum oxide ceramic ball is obtained while the production cost is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of ceramic grinding medium materials, and in particular to a La2O3-CeO2-doped bauxite-based high-density and high-wear-resistant alumina ceramic ball and a preparation method thereof. Background Art

[0002] Alumina wear-resistant ceramic balls are widely used as grinding media in industrial production because of their high strength, high hardness, and wear resistance. High-density alumina wear-resistant ceramic balls can greatly improve grinding efficiency and reduce energy consumption costs. In order to obtain high-density alumina wear-resistant ceramic balls, the alumina content is generally required to be between 80 and 99wt%. However, since alumina materials are difficult to sinter at low temperatures, a certain amount of low-temperature flux is introduced into the alumina material to promote the densification process of the alumina material. However, contradictory to this is that the glass 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, and during the sintering process, the excess liquid phase will induce the abnormal growth of Al2O3 crystals, resulting in a decrease in wear resistance.

[0003] In order to solve the above problems, the prior art provides a wear-resistant porcelain ball with a high iron content, in which 20-40wt% of iron oxide is introduced into the porcelain ball, combined with a potassium, calcium, magnesium, barium, aluminum, and silicon multi-element glass phase system, and γ-Al2O3 and iron oxide, potassium, calcium, magnesium, barium, aluminum, and silicon multi-element glass are controlled to form a spinel phase by oxidizing first and then reducing the firing method to improve the hardness and wear resistance, and reduce the sintering temperature of the porcelain ball. However, the disadvantage of this technology is that although iron oxide has a high density (5.1-5.2g / cm 3 ), however, Fe 3+ During the sintering process, it can enter the glass phase and spinel, forming a strong coloring effect. During long-term use, it will pollute the ground object, especially for daily-use porcelain, special pottery, papermaking and other industries that have high requirements for product whiteness. In addition, this technology uses γ-Al2O3 as the main source of alumina, and the main phase finally formed is the spinel phase, whose hardness is much smaller than that of alumina ceramic balls mainly composed of corundum phase.

[0004] Another solution widely used in the prior art is to add multiphase oxides to alumina ceramic balls, such as ZrSiO4 (4.7 g / cm 3 ) and t-ZrO2(6.1g / cm 3) is added to alumina ceramic materials to form composite ceramic materials, which inhibit the growth of grains through multiple grain boundaries, and promote sintering with complex rare earth oxides and calcium magnesium aluminum silicate liquid phase (CMAS). However, the disadvantage of this method is that Al2O3 and ZrO2 can hardly be eutectic, and the ceramic ball can only rely on the CMAS liquid phase to promote the sintering process. Therefore, when the ZrO2 content is high, the sintering process of the ceramic is inhibited, the degree of bonding between particles is reduced, and the density and strength of the material are adversely affected. Summary of the invention

[0005] The purpose of the present invention is to overcome the deficiencies of the prior art and provide a La2O3-CeO2-doped bauxite-based high-density, high-wear-resistant alumina ceramic ball, which uses titanium bauxite as a matrix, introduces La2O3-CeO2 for co-doping, forms a La-Ce-Ti-Ca-Si composite low-temperature eutectic, and realizes ceramic ball sintering at 1250-1350°C, thereby greatly reducing production costs and obtaining high-density, high-wear-resistant alumina ceramic balls. Another purpose of the present invention is to provide a preparation method and product of the above-mentioned La2O3-CeO2-doped bauxite-based high-density, high-wear-resistant alumina ceramic balls.

[0006] The purpose of the present invention is achieved through the following technical solutions:

[0007] The present invention provides a La2O3-CeO2 doped bauxite-based high-density and high-wear-resistant alumina ceramic ball, the raw materials of which are composed of 30-60 parts of titanium bauxite, 40-75 parts of α-Al2O3 micropowder, 5-10 parts of calcium carbonate, and 2-10 parts of rare earth oxide in parts by weight; the rare earth oxide is La2O3 and CeO2, and the mass ratio of La2O3:CeO2 is 1:1-2.5; the ceramic ball is sintered at 1250-1350°C, and the specific gravity of the obtained alumina ceramic ball is 3.5-3.8g / cm 3 , the wear resistance coefficient is 1.7~1.8g / kg / h.

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

[0009] Another object of the present invention is achieved by the following technical solutions:

[0010] The preparation method of the above-mentioned La2O3-CeO2 doped bauxite-based high-density and high-wear-resistant alumina ceramic ball provided by the present invention comprises the following steps:

[0011] (1) placing the titanium aluminum bauxite in a two-stage series ball mill for pre-grinding, that is, firstly performing a primary ball milling to obtain a coarse abrasive, and then performing a secondary ball milling on the coarse abrasive to obtain pre-ground titanium aluminum bauxite;

[0012] (2) mixing the pre-ground titanium aluminum alumina slurry with other raw materials according to a proportion, and then ball milling the mixture in a sand mill for 20 to 35 hours at a mass ratio of raw material: ball: water = 1: 1.2 to 2.5: 0.5 to 1 to obtain a mixed slurry;

[0013] (3) After the mixed slurry is spray granulated, rolled and dried, it is fired at a temperature of 1250-1350° C. and kept warm 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, the particle size of the pre-ground titanium aluminum alumina is D50<3 μm, and the particle size of the mixed slurry in step (2) is D50<1 μm.

[0015] The product is obtained by the preparation method of the La2O3-CeO2-doped bauxite-based high-density and high-wear-resistant alumina ceramic ball, wherein the chemical composition of the alumina ceramic ball is Al2O3 80-90wt%, SiO2 2-5wt%, Fe2O3 0.1-1wt%, TiO2 0.5-2wt%, RO+R2O 2-6wt%, La2O3 2-3wt%, and CeO2 3-7wt%.

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

[0017] (1) The present invention uses titanium alumina as the matrix. Titanium alumina 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 quickly infiltrates Al2O3 particles and penetrates into the gaps between particles, greatly reducing the firing temperature of the alumina ceramic ball, promoting the sintering process of the green body, and increasing the volume density of the alumina ceramic ball.

[0018] (2) The La-Ce-Ti-Ca-Si composite low-temperature eutectic formed in the present invention is different from the liquid phase (CMAS) in conventional alumina ceramic materials. 3+ With Ce 4+ The ionic radius is larger than Si 4+ The La-Ce-Ti-Ca-Si glass melt has a stable network structure, and the mass transfer process of high-valent ions in the glass melt is inhibited, which makes the Al2O3 grow slowly, the grain size is more uniform, and the size of the alumina grains in the ceramic ball is refined to form a fine-grained microstructure, which is beneficial to the improvement of the wear resistance of the ceramic ball.

[0019] (3) The La-Ce-Ti-Ca-Si composite eutectic of the present invention can change the phase composition of the neck joints between alumina particles. 4+ With Ti 4+ They are all variable valence oxides, and their ionic radius is similar to that of Al 3+ The phase difference is large, so it can only enter the Al2O3 lattice to form a limited solid solution. 2+ 、Si 4+ The combined effect of the above factors on the surface of Al2O3 crystals produces CaAl2TiO5, CaAl2Si2O8, CeAlO3 and other microcrystals. The neck connection between Al2O3 particles is strengthened, and the wear resistance and compressive strength of alumina ceramic balls are further improved.

[0020] (4) The titanium bauxite used in the present invention has a wide range of sources. The secondary ball milling process used to pretreat the bauxite and the subsequent sand milling process with other raw materials improves the reactivity of the bauxite particles. The obtained high-density and high-wear-resistant alumina ceramic balls have an Al2O3 content of 80 to 90wt%, which greatly reduces the production cost. The processing and procurement costs are also much lower than those of single α-Al2O3 ceramic balls and aluminum-zirconium composite ceramic balls.

[0021] The present invention will be described in further detail below with reference to the embodiments. DETAILED DESCRIPTION

[0022] The embodiment of the present invention provides a La2O3-CeO2 doped bauxite-based high-density and high-wear-resistant alumina ceramic ball, and its raw material composition is shown in Table 1.

[0023] Table 1 Raw material composition of La2O3-CeO2-doped bauxite-based high-density and high-wear-resistant alumina ceramic balls according to the present invention

[0024]

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

[0026] Table 2 Chemical composition of titanium alumina in the embodiment of the present invention (wt%)

[0027]

[0028] Wherein R2O represents an alkali metal oxide, and RO represents an alkaline earth metal oxide.

[0029] The present invention provides a method for preparing a La2O3-CeO2-doped bauxite-based high-density and high-wear-resistant alumina ceramic ball, the steps of which are as follows:

[0030] (1) placing the titanium aluminum alumina in a two-stage series ball mill for pre-grinding, i.e., firstly performing a primary coarse grinding to obtain a coarse abrasive with a particle size of D50 <10 μm, and then performing a secondary fine grinding on the coarse abrasive after screening to obtain a pre-ground titanium aluminum alumina with a particle size of D50 <3 μm;

[0031] (2) After the above-mentioned pre-ground titanium aluminum alumina slurry and other raw materials are mixed according to a proportion, the mass ratio of raw material: ball: water = 1: 1.2-2.5: 0.5-1 is used for ball milling for 20-35 hours in a sand mill to obtain a mixed slurry with a particle size of D50 <1 μm;

[0032] (3) After the mixed slurry is spray granulated, rolled and dried, it is fired at a temperature of 1250-1350° C. and kept warm for 30-120 minutes to obtain alumina ceramic balls.

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

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

[0035]

[0036] The chemical composition of the alumina ceramic balls prepared in 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 alumina ceramic balls prepared in various embodiments of the present invention

[0038]

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

[0040]

Claims

1. A La2O3-CeO2 doped bauxite-based high-density and high-wear-resistant alumina ceramic ball, characterized in that: The raw material composition is 30-60 parts of titanium aluminum bauxite, 40-75 parts of α-Al2O3 powder, 5-10 parts of calcium carbonate, and 2-10 parts of rare earth oxide in weight; the rare earth oxide is La2O3 and CeO2, and the mass ratio of La2O3:CeO2 is 1:1-2.5; the ceramic ball is sintered at 1250-1350°C, and the specific gravity of the obtained alumina ceramic ball is 3.5-3.8g / cm 3 , the wear resistance coefficient is 1.7~1.8g / kg / h.

2. The La2O3-CeO2 doped bauxite-based high-density and high-wear-resistant alumina ceramic ball according to claim 1, characterized in that: The chemical composition of the titanium-alumina is Al2O3 65-80wt%, SiO2 5-15wt%, Fe2O3 0.5-3wt%, TiO2 1-5.5wt%, RO+R2O 1.5-5.5wt%, IL 10-12wt%.

3. The method for preparing the La2O3-CeO2-doped bauxite-based high-density and high-wear-resistant alumina ceramic ball according to claim 1 or 2, characterized in that The following steps are involved: (1) placing the titanium aluminum bauxite in a two-stage series ball mill for pre-grinding, that is, firstly performing a primary ball milling to obtain a coarse abrasive, and then performing a secondary ball milling on the coarse abrasive to obtain pre-ground titanium aluminum bauxite; (2) mixing the pre-ground titanium aluminum alumina slurry with other raw materials according to a proportion, and then ball milling the mixture in a sand mill for 20 to 35 hours at a mass ratio of raw material: ball: water = 1: 1.2 to 2.5: 0.5 to 1 to obtain a mixed slurry; (3) After the mixed slurry is spray granulated, rolled and dried, it is fired at a temperature of 1250-1350° C. and kept warm for 30-120 minutes to obtain alumina ceramic balls.

4. The method for preparing the La2O3-CeO2-doped bauxite-based high-density and high-wear-resistant alumina ceramic ball according to claim 3, characterized in that: In the step (1), the particle size of the coarse abrasive is D50<10 μm, and the particle size of the pre-ground titanium-aluminum alumina is D50<3 μm.

5. The method for preparing the La2O3-CeO2-doped bauxite-based high-density and high-wear-resistant alumina ceramic ball according to claim 3, characterized in that: The particle size of the mixed slurry in step (2) is D50<1 μm.

6. A product obtained by the method for preparing La2O3-CeO2-doped bauxite-based high-density and high-wear-resistant alumina ceramic balls according to any one of claims 3 to 5, characterized in that: The chemical composition of the alumina ceramic ball is Al2O3 80-90wt%, SiO2 2-5wt%, Fe2O3 0.1-1wt%, TiO2 0.5-2wt%, RO+R2O 2-6wt%, La2O3 2-3wt%, and CeO2 3-7wt%.

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