Low water absorption ceramic material and method for producing the same

Abstract

The application provides a low water absorption ceramic material, which comprises the following raw materials in parts by mass: 50 parts of tailings, 10-25 parts of modified siliceous material, 2-8 parts of fluxing agent, and 1-5 parts of binder; wherein the modified siliceous material comprises a siliceous material and an apatite / silicon dioxide composite layer coated on the surface of the siliceous material; the apatite / silicon dioxide composite layer comprises apatite particles and a silicon-oxygen network formed by solidification of silica sol. The ceramic material takes tailings as a main material, and is optimized by the modified siliceous material, so that the reuse of solid waste can be realized, and the obtained ceramic material has a low water absorption.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to the technical field of ceramic preparation, in particular to a low water absorption ceramic material and a preparation method thereof. BACKGROUND

[0002] Ceramic materials are widely used in the fields of building decoration, home furnishing and industry due to their good mechanical properties, durability and decorative effect. However, traditional ceramics usually use minerals such as kaolin, feldspar and quartz as main raw materials. The reserves of such natural minerals are limited and the mining cost is high, resulting in high overall production cost of ceramic products.

[0003] In order to reduce the production cost and promote the resource utilization of solid waste, some researches have attempted to use tailings resources as the main raw material of ceramic body in recent years. Tailings usually contain certain siliceous and aluminous components, which have the feasibility of partially replacing natural minerals. However, the existing schemes for preparing ceramics mainly from tailings still have obvious deficiencies. Due to the complex mineral composition of tailings, the high-melting-point phase is not easy to densify during sintering, resulting in a large number of open pores in the body, which makes the ceramic products prepared mainly from tailings generally have a higher water absorption than traditional ceramic products, and it is difficult to meet the performance requirements of low water absorption ceramics.

[0004] For example, patent CN202410583007 discloses a solid waste-based composite foamed ceramic material, which is composed of a foamed ceramic material and a facing material. The preparation method comprises the following steps: mixing the main raw materials of iron tailings and tungsten tailings with water and then performing wet ball milling to obtain a slurry; drying and sintering the slurry to obtain a thermal insulation material; mixing coal gangue, manganese smelting slag and the like to obtain a powder, and then laying the powder on the surface of the thermal insulation material and performing secondary sintering to obtain the solid waste-based composite foamed ceramic material. The patent discloses a ceramic material with low water absorption prepared mainly from tailings.

[0005] However, the problem of the above patent is that the internal porosity of the composite foamed ceramic may be high, and the low water absorption depends on the barrier effect of the surface powder layer. Once cracks or peeling occur on the surface layer, the overall water absorption of the material may increase, thereby affecting the durability and application performance of the product.

[0006] Therefore, it is necessary to provide a ceramic material preparation technology which can effectively solve the problem of insufficient densification of the body and significantly reduce the water absorption of the ceramic material while realizing the high-value utilization of tailings and reducing the cost of raw materials. SUMMARY

[0007] The present application provides a preparation method of a low water absorption ceramic material, and the low water absorption ceramic material prepared by the method has a low water absorption.

[0008] In a first aspect, the application provides a low water absorption ceramic material, comprising the following raw materials by mass fraction: 50 parts of tailings, 10-25 parts of modified siliceous material, 2-8 parts of fluxing agent, and 1-5 parts of binder; wherein the modified siliceous material comprises a siliceous material and an apatite / silica composite layer coated on the surface of the siliceous material; the apatite / silica composite layer comprises apatite particles and a silicon-oxygen network formed by solidification of silica sol.

[0009] According to the application, the ceramic material can realize the resource utilization of industrial waste while maintaining the advantage of low water absorption, thereby reducing the overall raw material cost, and overcoming the problems of low densification and many internal pores of the ceramic prepared mainly from tailings, and can be applied to the application field of ceramic materials with high hydrophobicity requirements.

[0010] Specifically, the modified siliceous material can form a "coarse-fine-nanometer" three-stage gradation between the tailings and the siliceous material through in-situ deposition of apatite, thereby improving the overall bulk density of the material and reducing the internal voids of the material. In addition, the apatite can effectively hinder the penetration and expansion of pores through particle filling and space occupation, thereby further reducing the internal pore size of the ceramic after sintering and making the overall structure more dense. In addition, the apatite can combine with moisture in the environment at micro-cracks to release calcium ions and phosphate ions, and then form new crystal structures through deposition, which helps to restore the densification of the material when cracks appear on the surface or inside of the ceramic material. The silica sol forms a gel network structure between the apatite particles, and after solidification, it becomes a relatively dense apatite / silica coating layer that fixes the apatite particles and inhibits particle aggregation. At the same time, the Si-O-Si bond is formed with the surface of the siliceous material to form a relatively stable combination, and the modified siliceous material existing in the internal ceramic material can prevent pore connection and is beneficial to reducing the generation of water absorption paths.

[0011] In addition, the addition of the fluxing agent in the raw materials can promote liquid phase sintering and reduce the generation of pores, and the addition of the binder can provide good plasticity to ensure that the green body structure is uniform and dense, and avoid macroscopic water absorption channels caused by forming defects.

[0012] Therefore, the low water absorption ceramic material provided by the application uses tailings as the main material, optimizes the modified siliceous material, reduces the raw material cost, and forms a relatively dense and low water absorption ceramic material.

[0013] In some embodiments, the tailings comprise metal tailings and non-metal tailings, and the mass fraction ratio of the metal tailings to the non-metal tailings is 10:2.5-3.5, wherein the metal tailings comprise vanadium-titanium magnetite tailings, and the non-metal tailings comprise phosphorus tailings.

[0014] In some of the above embodiments, the metal tailings and non-metal tailings are selected to be compounded as the main raw materials of the ceramic, the metal tailings can be used as active phase to reduce the sintering temperature and promote liquid phase sintering, and the non-metal tailings can be used as fluxing phase to form a low viscosity glass liquid phase at high temperature, which promotes the contact and bonding of particles. After compounding, a solid-liquid phase sintering system can be formed, which can promote densification and maintain structural stability. When the mass ratio of the metal tailings and the non-metal tailings is controlled to be 10:2.5-3.5, the active components in the metal tailings can promote the formation of liquid phase and induce the formation of grains, and the glass phase formed by the fluxing components in the non-metal tailings can help to fill and seal the pores, so that the prepared ceramic has a lower water absorption. Further, vanadium-titanium magnetite tailings and phosphorus tailings are selected as the main materials of the ceramic green body. On the one hand, the vanadium-titanium magnetite tailings contain Fe, Ti, V and other multivalent ions, which can promote electron transition and form metastable oxygen vacancies during sintering. The introduction of oxygen vacancies is beneficial to the densification of the ceramic material, and part of Fe and Ti can become heterogeneous nucleation points under high temperature conditions, inducing the formation of aluminum titanate, spinel and other crystal phases with high hardness, which are dispersed in the material to inhibit the generation of cracks caused by sintering deformation, thereby reducing the water absorption. On the other hand, P2O5 in the phosphorus tailings can react with SiO2 and other oxides in the system to form phosphate-silicate composite glass phase. This glass system has low viscosity and good fluidity, which can effectively improve the density of the green body. In addition, there is a synergistic effect between the vanadium-titanium magnetite tailings and the phosphorus tailings. The Fe 3+ 、Ti 4+ provided by the vanadium-titanium magnetite tailings and the Ca 2+ 、P 5+ provided by the phosphorus tailings have an ionic compensation mechanism, which tends to react preferentially at the contact interface under high temperature, possibly generating calcium-iron oxides, iron phosphate, calcium titanate, titanium phosphate and other compounds. These in-situ generated crystal phases have low porosity and strong interfacial bonding, which can fill the grain boundary pores and inhibit the penetration of pores. During the sintering process, the phosphorus tailings contain a large amount of fluxing components, which can provide a good fluidity basis for densification. As the temperature rises, the active components such as Fe and Ti in the vanadium-titanium magnetite tailings gradually melt into the glass phase formed by the phosphorus tailings, which can increase the viscosity of the glass phase, inhibit the deformation of the green body, reduce the pores and inhibit the shrinkage, and thus reduce the water absorption of the ceramic.

[0015] In some embodiments, the metal tailings further include molybdenum tailings, and the mass ratio of the vanadium-titanium magnetite tailings and the molybdenum tailings is 10:1-2.

[0016] In some of the above embodiments, the addition of molybdenum tailings to the vanadium-titanium magnetite tailings can further reduce the water absorption of the material. This can be attributed to the low-melting-point molybdenum species in the molybdenum tailings, which can promote the rearrangement of the hard skeleton, such as Fe-Ti-O particles, in the vanadium-titanium magnetite tailings, improve the fluidity, and thus reduce the larger pores. When the mass ratio of vanadium-titanium magnetite tailings to molybdenum tailings is controlled at 10:1-2, the low-melting-point molybdenum species can be appropriately filled in the liquid phase, which can make the ceramic material more dense and have a lower water absorption.

[0017] In some embodiments, the method for preparing the modified siliceous material comprises the following steps:

[0018] S1: activating the siliceous material in an alkaline solution;

[0019] S2: treating the activated siliceous material in a solution containing an amino silane coupling agent to form amino-containing organic silicon anchor sites on the surface of the siliceous material;

[0020] S3: immersing the siliceous material with amino groups on the surface in a solution containing calcium salt to bond the amino end groups with calcium ions, and then transferring into a solution containing phosphate to adjust the pH to 7-8, so that apatite is deposited in situ on the surface of the siliceous material;

[0021] S4: dispersing the siliceous material with apatite particles on the surface in a silica sol to form a silica gel network on the apatite particles and the surface of the siliceous material;

[0022] S5: calcining the siliceous material with the silica gel network and apatite particles on the surface to remove organic residues and solidify the silica network, to obtain a modified siliceous material with a composite layer of apatite / silica on the surface.

[0023] In some of the above embodiments, the method for preparing the modified siliceous material can form more -Si-OH sites on the surface of the siliceous material by activating the siliceous material in an alkaline solution, which can enhance the bonding capacity with the coupling agent.

[0024] In step S2, the introduction of amino groups on the surface of the activated siliceous material by the amino silane coupling agent treatment can build a bridge between the siliceous material and the composite layer, which can promote the subsequent adsorption of calcium ions and the nucleation of apatite.

[0025] In step S3, the calcium salt solution provides sufficient calcium source, and the -NH2 and Ca 2+ Through coordination bonding, a relatively stable adsorption layer is formed, which provides active sites for the subsequent nucleation of apatite; adjusting the pH to an alkaline environment can make the phosphate react with Ca 2+ to generate hydroxyapatite particles.

[0026] In step S4, the silica sol is infiltrated into the interstitial space of the apatite particles by silica sol immersion treatment, plays a role of physical fixation, inhibits agglomeration of the apatite particles, and can form a continuous silica gel network covering the surface of the apatite and the siliceous material. In addition, the silica sol can also infiltrate into the pores of the siliceous material, thereby reducing the water absorption.

[0027] In step S5, the siliceous material with the surface covered by the silica gel network and the apatite particles is subjected to calcination treatment, which can remove the residual organic components in the previous steps and promote dehydration and condensation of the silica gel network. The silica gel that has partially infiltrated into the pores of the siliceous material can seal the pores of the siliceous material after heat treatment. The apatite particles and the silica network are further combined by chemical bonds at high temperature, forming a phosphorapatite / silica composite layer, and the structure of the prepared modified siliceous material is more compact.

[0028] The method can realize the sealing of the pores of the material and the reduction of the water absorption by constructing the phosphorapatite / silica composite coating layer in steps, using amino silane as a bridge to anchor calcium ions to induce apatite deposition, and then forming a network structure by silica sol infiltration, and finally forming a relatively compact core-shell coating layer.

[0029] In some embodiments, the siliceous material includes perlite and silica fume, and the mass ratio of the perlite to the silica fume is 2:0.5-1.5.

[0030] In some embodiments, the perlite and the silica fume are used as the siliceous material, and the ceramic material obtained has a lower water absorption. The reason may be that the perlite expands at high temperature, can fill the larger pores in the material, and reduce the porosity. The fine pores formed inside the perlite due to high-temperature expansion are further filled by the silica fume, which can inhibit the fine pores from being connected, block the capillary water absorption path, and reduce the water absorption. The multi-scale structure formed by the joint action of the perlite and the silica fume can improve the overall density of the material. In addition, because the silica fume has a high specific surface area, the hydroxyl groups on its surface can react with Ca 2+ 、PO4 3- in the apatite to form a nucleation interface for secondary deposition, which is beneficial to the apatite in filling the fine pores and reducing the water absorption. When the mass ratio of the perlite to the silica fume is controlled to be 2:0.5-1.5, the internal pores of the material are small, the silica fume is appropriately filled, and the space for dynamic repair of the apatite is reserved, so that the ceramic material has a low water absorption.

[0031] In some embodiments, the amino silane coupling agent includes 3-aminopropyl triethoxysilane.

[0032] In some of the above embodiments, the amino silane coupling agent has a bifunctional structure, one end of which can be anchored to the substrate surface of the siliceous material, and the other end of which can provide a potential active site for apatite nucleation. As an example, 3-aminopropyl triethoxysilane is selected as the amino silane coupling agent in an embodiment of the present application, which can make the obtained apatite / silica composite layer more uniform and have stronger binding force.

[0033] In some embodiments, the solution containing phosphate further comprises fluoride, wherein the fluoride comprises ammonium fluoride.

[0034] In some of the above embodiments, after the addition of fluoride, F - The fluoride can replace part of the -OH to form fluorohydroxyapatite, F - which can enter the lattice channel sites of apatite, enhance the order of the crystal and reduce structural defects, possibly making the lattice more stable and slowing down the dissolution rate, thereby improving the hydrophobicity of the material. As an example, ammonium fluoride is selected as the fluoride in an embodiment of the present application.

[0035] In some embodiments, the silica sol is prepared using at least one of tetraethoxysilane and methyltrimethoxysilane as a silicon source.

[0036] In some of the above embodiments, tetraethoxysilane (TEOS) has good film-forming and coating properties, can form a relatively dense and uniform siloxane network layer, and can optimize the densification of the material. Methyltrimethoxysilane (MTMS) can retain Si-CH3 in the network formed after hydrolysis and condensation, the steric hindrance provided by the methyl group can slow down the condensation rate, reduce the risk of cracking, and the non-polar methyl group can also inhibit the hydrogen bonding and capillary wetting phenomenon between the coating layer and water, thereby making the material have a lower water absorption rate. The combined action of TEOS and MTMS can obtain a relatively dense and more hydrophobic siloxane network layer structure.

[0037] In some embodiments, the method for preparing the modified siliceous material comprises the following steps:

[0038] S1: 15 parts of perlite and 8-11 parts of silica fume are mixed and then placed in an aqueous NH4OH solution, activated at 60-80°C for 10-60 min, and the molar concentration of NH4OH is 0.04-0.06 mol / L;

[0039] S2: the activated siliceous material is dispersed in a 0.5-1.5 wt% aqueous / ethanol solution of 3-aminopropyl triethoxysilane, and reacted at 60-80°C for 1-2 h to obtain an NH2-siliceous material;

[0040] S3: immerse the NH2-siliceous material in a solution containing calcium salt, the molar concentration of calcium element is 0.1-0.2 mol / L, stir for 1-2 h; then transfer into a solution containing phosphate and fluoride, the molar concentration of phosphorus element is 0.05-0.1 mol / L, the molar concentration of fluorine element is 1-2 mmol / L, add 0.25-0.35 mol / L of urea aqueous solution to adjust the pH to 7-8, and age for 1-2 h to obtain the apatite / siliceous material;

[0041] S4: configure tetraethoxysilane, methyltrimethoxysilane, water and ethanol according to the mass ratio of 10:1-2:20-40:40-80 to obtain silica sol, and after aging for 1-2 h, place the apatite / siliceous material in the silica sol, and perform ultrasonic and immersion treatment, so that a silica gel network is formed on the surface of the material;

[0042] S5: calcine the siliceous material coated with the silica gel network and apatite particles at 400-700℃ for 20-60 min to remove organic residues and solidify the silica network, thereby obtaining a modified siliceous material coated with an apatite / silica composite layer.

[0043] In some of the above embodiments, the reaction conditions and the amount ratio of each step in the preparation process of the modified siliceous material are specifically described. Under the above conditions, the modified siliceous material can significantly reduce the water absorption of the ceramic material.

[0044] In some embodiments, the raw material satisfies at least one of the following conditions:

[0045] 1) the fluxing agent comprises at least one of feldspar, dolomite, talc, and waste glass powder;

[0046] 2) the binder comprises at least one of kaolin, bentonite, polyvinyl alcohol, and carboxymethyl cellulose.

[0047] In some of the above embodiments, the use of the above fluxing agent can reduce the sintering temperature of the system and promote the formation of liquid phase, and the use of the above binder can inhibit excessive sintering, shrinkage and cracking of the material during the green body forming stage, thereby improving the density of the ceramic material.

[0048] In a second aspect, the application provides a preparation method of a low-water-absorption ceramic material, comprising:

[0049] providing the raw material of the low-water-absorption ceramic material according to any one of the embodiments of the first aspect, wet ball milling the raw material with water to obtain a slurry, drying and granulating, and then pressing to form a green body;

[0050] firing the green body to obtain the low-water-absorption ceramic material.

[0051] According to the present application, the metal tailings in the preparation method act as a rigid skeleton to limit shrinkage, and the non-metal tailings act as a glass phase to drive particle rearrangement, and in-situ crystallization at the interface under the synergistic effect of the two provides fluxing grains, improves the pore structure and enhances the material density, the modified siliceous material filled in the green body can further realize multi-scale densification and possibly promote the repair of micro-cracks inside the material, the tailings, modified siliceous material, fluxing agent, and binder are wet ball milled according to the formula amount to obtain a slurry, the particle size of the raw materials tends to be uniform and fully contacts, providing a basis for subsequent sintering reaction and densification, drying, granulating, and pressing to obtain a green body, and finally sintering the green body to obtain a ceramic material with low water absorption.

[0052] In some embodiments, the sintering conditions include:

[0053] The green body is placed in a calcining furnace, first in an oxygen-containing atmosphere, the furnace temperature is raised to 700-900℃, then in an inert atmosphere containing atomized organic silicon compounds, the temperature is kept at 700-900℃ for 50-100min, then in an oxygen-containing atmosphere, the furnace temperature is raised to 1100-1200℃, and then kept for 30-120min.

[0054] The injection rate of the atomized organic silicon compound is 0.1-0.5mL / min.

[0055] In some of the above embodiments, the organic silicon compound can undergo molecular chain rupture in a high-temperature inert gas environment, releasing low-molecular-weight silicon-based compounds, and the low-molecular-weight silicon-based compound particles produced by cracking can directly fill the surface pores of the material or combine with oxygen on the surface of the green body to form an amorphous film, thereby reducing the porosity of the ceramic material, and in a subsequent oxygen-containing environment, the increase in temperature can further promote the densification of the silicon dioxide layer, reducing the water absorption of the ceramic material.

[0056] In some embodiments, the atomized organic silicon compound includes tetraethoxysilane and methyltriethoxysilane, and the mass ratio of tetraethoxysilane to methyltriethoxysilane is 6:1.5-2.5.

[0057] In some of the above embodiments, tetraethoxysilane (TEOS) and methyltriethoxysilane (MTES) are selected as the organic silicon compound atmosphere, and the ceramic material prepared has a low water absorption rate. The reason may be that, in the TEOS cracking process, a polycondensation reaction is prone to occur, and a highly cross-linked amorphous SiO2 network can be formed. The methyl groups in MTES can inhibit excessive cross-linking, and a granular silicon oxide phase is easily formed. In addition, the hydrophobic methyl groups can introduce organic substituents during deposition, reduce the hydrophilicity of the surface of the deposition product, and the methyl groups can form carbon residues after pyrolysis, thereby further reducing the surface energy and reducing the adsorption of water molecules by the pores.

[0058] Compared with the prior art, the application has at least the following beneficial effects:

[0059] By using tailings as the main raw material and combining modified siliceous materials, a "coarse-fine-nano" three-stage grading structure is formed inside the ceramic body, which can improve the bulk density and compactness of the raw material, thereby reducing the porosity and water absorption of the material. The active components such as Fe, Ti, and P contained in the tailings can have a synergistic effect with the modified siliceous materials during sintering, promoting liquid phase sintering and crystal phase formation, and further optimizing the microstructure stability of the ceramic. At the same time, the modified siliceous material has a certain self-healing ability, which can repair cracks on the surface or inside the material through the dissolution-redeposition process of ions in the presence of environmental moisture, thereby maintaining the long-term low water absorption characteristics of the material. The low water absorption ceramic material and the preparation method provided by the application can reduce the cost of raw materials while preparing a ceramic material with a relatively dense structure and a low water absorption rate, and can be applied to buildings and decorations with high requirements for impermeability and waterproofness. DETAILED DESCRIPTION

[0060] Each embodiment or implementation in the specification is described in a progressive manner, and each embodiment focuses on the differences from other embodiments.

[0061] In the description of the specification, the description of the terms "one embodiment", "some embodiments", "exemplary embodiment", "example", "specific example", or "some examples" means that the specific features, structures, materials, or characteristics described in conjunction with the implementation or example are included in at least one implementation or example of the application. In the specification, the exemplary description of the above terms does not necessarily refer to the same implementation or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in any one or more implementations or examples in a suitable manner.

[0062] In addition, the terms "first", "second", etc. are used only for descriptive purposes and do not connote or imply relative importance or an ordering between or among the indicated technical features. Thus, a feature defined with "first", "second", etc. can include at least one of the features implicitly or explicitly. In the description of the present application, "a plurality of" means at least two, for example, two, three, etc., unless otherwise specifically defined.

[0063] In the description of the present application, "parts" means "mass parts" unless otherwise specifically stated.

[0064] Hereinafter, the examples of the present application will be described. The examples described below are illustrative and are intended to explain the present application, and are not to be construed as limiting the present application. In the examples, the specific techniques or conditions not mentioned are performed according to the techniques or conditions described in the literature in the art or according to the product manual. The reagents or instruments not mentioned the manufacturer are all conventional products that can be obtained commercially.

[0065] 3-aminopropyltriethoxysilane: CAS No. 919-30-2;

[0066] tetraethoxysilane: CAS No. 78-10-4;

[0067] methyltrimethoxysilane: CAS No. 1185-55-3;

[0068] methyltriethoxysilane: CAS No. 2031-67-6;

[0069] Vanadium-titanium magnetite tailings: the main components are SiO2: 40-50%, CaO: 20-30%, Fe2O3: 10-20%, Al2O3: 5-10%, MgO: 5-10%, K2O: 1-4%, TiO2: 1-2%, Na2O: 1-2%, and the content of other impurities is not more than 2%;

[0070] Phosphorus tailings: the main components are CaO: 40-50%, MgO: 30-40%, SiO2: 20-30%, P2O5: 2-4%, and the content of other impurities is not more than 2%;

[0071] Molybdenum tailings: the main components are SiO2: 70-80%, Al2O3: 10-20%, Fe2O3: 5-10%, CaO: 2-5%, TiO2: 1-2%, MoO3: 0-1%, and the content of other impurities is not more than 2%.

[0072] Preparation Example 1

[0073] Preparation of modified siliceous material:

[0074] S1: 15 parts of perlite and 10 parts of silica fume were mixed and placed in a 0.05 mol / L NH4OH aqueous solution, with a solid-liquid ratio of 1 g:10 mL, activated at 70°C for 30 min, washed with deionized water three times, dried at 80°C for 6 h, ground and passed through a 200-mesh sieve to obtain the activated siliceous material;

[0075] S2: The activated siliceous material was dispersed in a 1 wt% 3-aminopropyl triethoxysilane water / ethanol solution (water / ethanol volume ratio of 7 / 3), with a solid-liquid ratio of 1 g:10 mL, stirred at 70°C for 1 h, and in the process, a 0.05 mol / L NH4OH aqueous solution was used to adjust the pH value of the solution to keep it at 9. After the reaction, the material was washed with water and ethanol once respectively, and dried at 80°C for 6 h to obtain the NH2-siliceous material;

[0076] S3: The NH2-siliceous material was immersed in a Ca(NO3)2·4H2O solution, with a calcium element molar concentration of 0.15 mol / L, and a solid-liquid ratio of 1 g:10 mL, and stirred for 1 h. The above material was then filtered and transferred into a solution containing NaH2PO4·2H2O, Na2HPO4, and NH4F, with a phosphorus element molar concentration of 0.09 mol / L and a fluorine element molar concentration of 1.5 mmol / L. A 0.3 mol / L urea was slowly added dropwise at 70°C, and the pH value was adjusted to 8, and then the material was continuously incubated for 2 h. The material was washed with deionized water three times, and dried at 80°C for 6 h to obtain the apatite / siliceous material;

[0077] S4: A silica sol was prepared according to the mass ratio of tetraethoxysilane:methyltrimethoxysilane:water:ethanol=10:1.5:20:40, and aged at 60°C for 1 h. The above apatite / siliceous material was then immersed in the silica sol, with a solid-liquid ratio of 1 g:10 mL, and ultrasonically treated for 15 min (frequency 40 kHz, power 200 w), and incubated at 60°C for 2 h. The material was washed with ethanol once, and dried at 80°C for 10 h to obtain the siliceous material with an apatite / silica gel network formed on the surface;

[0078] S5: The above material was incubated at 450°C for 40 min (air atmosphere, heating rate 5°C / min) to remove organic residues and solidify the silica network, to obtain the modified siliceous material A coated with an apatite / silica composite layer on the surface.

[0079] Preparation Example 2

[0080] Preparation of modified siliceous material:

[0081] S1: 15 parts of perlite and 10 parts of silica fume were mixed and placed in a 0.05 mol / L NH4OH aqueous solution, with a solid-liquid ratio of 1 g:10 mL, activated at 70°C for 30 min, washed with deionized water three times, dried at 80°C for 6 h, ground and passed through a 200-mesh sieve to obtain the activated siliceous material;

[0082] S2: The activated siliceous material was dispersed in a 1 wt% 3-aminopropyl triethoxysilane water / ethanol solution (water / ethanol volume ratio of 7 / 3), with a solid-liquid ratio of 1 g:10 mL, stirred at 70°C for 1 h, and in the process, a 0.05 mol / L NH4OH aqueous solution was used to adjust the pH value of the solution to keep it at 9. After the reaction, the material was washed with water and ethanol once respectively, and dried at 80°C for 6 h to obtain the NH2-siliceous material;

[0083] S3: The NH2-siliceous material was immersed in a Ca(NO3)2·4H2O solution, with a calcium element molar concentration of 0.15 mol / L, and a solid-liquid ratio of 1 g:10 mL, and stirred for 1 h. The above material was then filtered and transferred into a solution containing NaH2PO4·2H2O and Na2HPO4, with a phosphorus element molar concentration of 0.09 mol / L. 0.3 mol / L urea was slowly added under the condition of 70°C, and the pH value was adjusted to 8. After 2 h of continued incubation, the material was washed with deionized water three times, and dried at 80°C for 6 h to obtain the apatite / siliceous material;

[0084] S4: A silica sol was prepared according to the mass ratio of tetraethoxysilane:methyltrimethoxysilane:water:ethanol = 10:1.5:20:40, and aged at 60°C for 1 h. The above apatite / siliceous material was then immersed in the silica sol, with a solid-liquid ratio of 1 g:10 mL, and ultrasonically treated for 15 min (frequency 40 kHz, power 200 w). After incubation at 60°C for 2 h, the material was washed with ethanol once, and dried at 80°C for 10 h to obtain the siliceous material with an apatite / silica gel network formed on the surface;

[0085] S5: The above material was incubated at 450°C for 40 min (air atmosphere, heating rate 5°C / min) to remove organic residues and solidify the silica network, thereby obtaining the modified siliceous material B coated with an apatite / silica composite layer on the surface.

[0086] Preparation Example 3

[0087] Preparation of the modified siliceous material:

[0088] S1: 15 parts of perlite and 10 parts of silica fume were mixed and placed in a 0.05 mol / L NH4OH aqueous solution, with a solid-liquid ratio of 1 g:10 mL, activated at 70°C for 30 min, washed with deionized water three times, dried at 80°C for 6 h, ground and passed through a 200-mesh sieve to obtain the activated siliceous material;

[0089] S2: The activated siliceous material was dispersed in a 1 wt% 3-aminopropyl triethoxysilane water / ethanol solution (water / ethanol volume ratio of 7 / 3), with a solid-liquid ratio of 1 g:10 mL, stirred at 70°C for 1 h, and in the process, a 0.05 mol / L NH4OH aqueous solution was used for adjustment, so that the solution pH value remained at 9. After the reaction, the material was washed with water and ethanol once respectively, and dried at 80°C for 6 h to obtain the NH2-siliceous material;

[0090] S3: The NH2-siliceous material was immersed in a Ca(NO3)2·4H2O solution, with a calcium element molar concentration of 0.15 mol / L, and a solid-liquid ratio of 1 g:10 mL, and stirred for 1 h. The above material was then filtered and transferred into a solution containing NaH2PO4·2H2O, Na2HPO4, and NH4F, with a phosphorus element molar concentration of 0.09 mol / L and a fluorine element molar concentration of 1.5 mmol / L. 0.3 mol / L urea was slowly added under the condition of 70°C, and the pH was adjusted to 8. After 2 h of continued incubation, the material was washed with deionized water three times, and dried at 80°C for 6 h to obtain the apatite / siliceous material;

[0091] S4: A silica sol was prepared according to the mass ratio of tetraethoxysilane:water:ethanol=11.5:20:40, and aged at 60°C for 1 h. The above apatite / siliceous material was then immersed in the silica sol, with a solid-liquid ratio of 1 g:10 mL, and ultrasonically treated for 15 min (frequency 40 kHz, power 200 w). After incubation at 60°C for 2 h, the material was washed with ethanol once, and dried at 80°C for 10 h to obtain the siliceous material with an apatite / silica gel network formed on the surface;

[0092] S5: The above material was incubated at 450°C for 40 min (air atmosphere, heating rate 5°C / min) to remove organic residues and solidify the silica network, thereby obtaining the modified siliceous material C coated with an apatite / silica composite layer.

[0093] Preparation Example 4

[0094] Preparation of the modified siliceous material:

[0095] S1: 25 parts of perlite were mixed and then placed in a 0.05 mol / L NH4OH aqueous solution, with a solid-liquid ratio of 1 g:10 mL, activated at 70°C for 30 min, washed with deionized water three times, dried at 80°C for 6 h, ground and then passed through a 200-mesh sieve to obtain the activated siliceous material;

[0096] S2: The activated siliceous material was dispersed in a 1 wt% 3-aminopropyl triethoxysilane aqueous / ethanol solution (water / ethanol volume ratio of 7 / 3), with a solid-liquid ratio of 1 g:10 mL, stirred at 70°C for 1 h, and in this process, a 0.05 mol / L NH4OH aqueous solution was used for adjustment, so that the solution pH value was maintained at 9, after the reaction, washed with water and ethanol once respectively, dried at 80°C for 6 h to obtain the NH2-siliceous material;

[0097] S3: The NH2-siliceous material was immersed in a Ca(NO3)2·4H2O solution, with a calcium element molar concentration of 0.15 mol / L, a solid-liquid ratio of 1 g:10 mL, and stirred for 1 h; the above material was filtered and then transferred into a solution containing NaH2PO4·2H2O, Na2HPO4, and NH4F, with a phosphorus element molar concentration of 0.09 mol / L and a fluorine element molar concentration of 1.5 mmol / L, 0.3 mol / L urea was slowly added dropwise at 70°C, the pH was adjusted to 8, and then the solution was continuously incubated for 2 h, washed with deionized water three times, and dried at 80°C for 6 h to obtain the apatite / siliceous material;

[0098] S4: A silica sol was prepared according to the mass ratio of tetraethoxysilane:methyltrimethoxysilane:water:ethanol=10:1.5:20:40, and then the above apatite / siliceous material was immersed in the silica sol, with a solid-liquid ratio of 1 g:10 mL, ultrasonic treatment for 15 min (frequency 40 kHz, power 200 w), incubation at 60°C for 2 h, washing with ethanol once, and drying at 80°C for 10 h to obtain the siliceous material with an apatite / silica gel network formed on the surface;

[0099] S5: The above material was incubated at 450°C for 40 min (air atmosphere, heating rate 5°C / min) to remove organic residues and solidify the silica network, to obtain the modified siliceous material D coated with an apatite / silica composite layer on the surface.

[0100] Comparative Preparation Example 1

[0101] Preparation of the modified siliceous material:

[0102] S1: 15 parts of perlite and 10 parts of silica ash were mixed and placed in a 0.05 mol / L NH4OH aqueous solution, with a solid-liquid ratio of 1 g:10 mL, activated at 70°C for 30 min, washed with deionized water three times, dried at 80°C for 6 h, ground and sieved through a 200-mesh sieve to obtain the activated siliceous material;

[0103] S2: The activated siliceous material was dispersed in a 1wt% 3-aminopropyl triethoxysilane water / ethanol solution (water / ethanol volume ratio of 7 / 3), with a solid-liquid ratio of 1 g:10 mL, stirred at 70°C for 1 h, and in the process, a 0.05 mol / L NH4OH aqueous solution was used to adjust the pH value of the solution to 9. After the reaction, the solution was washed with water and ethanol once respectively, and dried at 80°C for 6 h to obtain the NH2-siliceous material;

[0104] S3: The NH2-siliceous material was immersed in a Ca(NO3)2·4H2O solution, with a calcium element molar concentration of 0.15 mol / L, and a solid-liquid ratio of 1 g:10 mL, and stirred for 1 h. The material was then filtered and transferred into a solution containing NaH2PO4·2H2O, Na2HPO4, and NH4F, with a phosphorus element molar concentration of 0.09 mol / L and a fluorine element molar concentration of 1.5 mmol / L. A 0.3 mol / L urea was slowly added under the condition of 70°C, and the pH value was adjusted to 8. After 2 h of continued incubation, the solution was washed with deionized water three times, and dried at 80°C for 6 h to obtain the modified siliceous material E.

[0105] Example 1

[0106] Preparation of low-water-absorption ceramic material:

[0107] M1: Vanadium-titanium magnetite tailings, phosphorus tailings, molybdenum tailings, modified siliceous material A prepared in Preparation Example 1, feldspar, dolomite, and bentonite were respectively crushed and ground to 100 mesh, and dried at 105°C for 4 h;

[0108] M2: 33.5 parts of vanadium-titanium magnetite tailings, 11.5 parts of phosphorus tailings, 5 parts of molybdenum tailings, 15 parts of modified siliceous material A prepared in Preparation Example 1, 3 parts of feldspar, 2 parts of dolomite, and 3 parts of bentonite were mixed according to the mass fraction, and the above raw materials were added to water for wet ball milling, with a solid-liquid ratio of 1:1.5, a zirconia ball material to slurry volume ratio of 3:1, a ball milling speed of 300 rpm, and a ball milling time of 10 h. After ball milling, the slurry was sieved through a 200-mesh sieve to remove coarse particles to obtain a uniform slurry;

[0109] M3: The uniform slurry was sent to a spray drying device for granulation, with an inlet air temperature of 160°C and an outlet air temperature of 80°C. After drying, the particles were ground and sieved through a 300-mesh sieve to obtain dry powder for molding;

[0110] M4: The powder is loaded into a mold and pressed, first pre-pressing 10 MPa for 30 s, then main pressing 200 MPa for 60 s, to obtain a green body, which is then air dried at room temperature for 12 h, and then oven dried at 120℃ for 6 h, to obtain a shaped green body;

[0111] M5: 6 parts of tetraethoxysilane and 2 parts of methyltriethoxysilane are dissolved in 72 parts of anhydrous isopropanol, and ultrasonic treatment is performed for 15 min (frequency 40 kHz, power 300 w), to obtain a silicone precursor solution, which is placed in an ultrasonic atomizer and used later;

[0112] M6: The shaped green body is placed in a calcination furnace, the temperature is raised to 750℃ at a rate of 5℃ / min, and then the temperature is kept at 750℃, the air inlet is closed, and nitrogen replacement is started (nitrogen flow 5 L / min), when the oxygen content in the furnace is reduced to 0.5 vol% and stabilized, the silicone precursor is atomized by an atomizer and brought into the furnace by nitrogen (atomization injection rate 0.3 mL / min, nitrogen flow 3 L / min), the atomization time is 60 min, after the end, nitrogen is continuously introduced for 20 min (nitrogen flow 5 L / min), the nitrogen introduction is stopped, the air inlet is opened, and the temperature is raised to 1150℃ at a rate of 5℃ / min, and kept for 60 min, after the end of the holding, the furnace is naturally cooled to room temperature, to obtain a low water absorption ceramic material.

[0113] Example 2

[0114] Preparation of a low water absorption ceramic material:

[0115] The same as example 1, the only difference is that the types of tailings in the raw materials are different, and the specific difference is that:

[0116] M1: Vanadium-titanium magnetite tailings, phosphorus tailings, modified siliceous material A prepared in preparation example 1, feldspar, dolomite, bentonite are respectively crushed and ground to 100 mesh, and dried at 105℃ for 4h;

[0117] M2: 38.5 parts of vanadium-titanium magnetite tailings, 11.5 parts of phosphorus tailings, 15 parts of modified siliceous material A prepared in preparation example 1, 3 parts of feldspar, 2 parts of dolomite, and 3 parts of bentonite are mixed, and the above raw materials are added to water for wet ball milling, the solid-liquid ratio is 1:1.5, the zirconia ball material and slurry volume ratio is 3:1, the ball milling speed is 300 rpm, and the ball milling time is 10 h, after the ball milling is completed, the slurry is passed through a 200 mesh screen to remove coarse particles, to obtain a uniform slurry.

[0118] Example 3

[0119] Preparation of a low water absorption ceramic material:

[0120] The same as example 1, the only difference is the tailings mass ratio in raw materials, specifically different in:

[0121] M1: Vanadium-titanium magnetite tailings, phosphorus tailings, molybdenum tailings, modified siliceous material A prepared in preparation example 1, feldspar, dolomite, bentonite are respectively crushed, ground to 100 mesh, dried at 105℃ for 4h;

[0122] M2: 36.5 parts of vanadium-titanium magnetite tailings, 8 parts of phosphorus tailings, 5.5 parts of molybdenum tailings, 15 parts of modified siliceous material A prepared in preparation example 1, 3 parts of feldspar, 2 parts of dolomite, 3 parts of bentonite are mixed by mass fraction, the above raw materials are added to water for wet ball milling, the solid-liquid ratio is 1:1.5, the volume ratio of zirconia balls to slurry is 3:1, the ball milling speed is 300rpm, the ball milling time is 10h, after ball milling, the slurry is passed through a 200 mesh screen, and the coarse particles are removed to obtain a uniform slurry.

[0123] Example 4

[0124] Preparation of low water absorption ceramic material:

[0125] The same as example 1, the only difference is the tailings mass ratio in raw materials, specifically different in:

[0126] M1: Vanadium-titanium magnetite tailings, phosphorus tailings, molybdenum tailings, modified siliceous material A prepared in preparation example 1, feldspar, dolomite, bentonite are respectively crushed, ground to 100 mesh, dried at 105℃ for 4h;

[0127] M2: 31 parts of vanadium-titanium magnetite tailings, 14.5 parts of phosphorus tailings, 4.5 parts of molybdenum tailings, 15 parts of modified siliceous material A prepared in preparation example 1, 3 parts of feldspar, 2 parts of dolomite, 3 parts of bentonite are mixed by mass fraction, the above raw materials are added to water for wet ball milling, the solid-liquid ratio is 1:1.5, the volume ratio of zirconia balls to slurry is 3:1, the ball milling speed is 300rpm, the ball milling time is 10h, after ball milling, the slurry is passed through a 200 mesh screen, and the coarse particles are removed to obtain a uniform slurry.

[0128] Example 5

[0129] Preparation of low water absorption ceramic material:

[0130] M1: Vanadium-titanium magnetite tailings, phosphorus tailings, molybdenum tailings, modified siliceous material A prepared in preparation example 1, feldspar, dolomite, bentonite are respectively crushed, ground to 100 mesh, dried at 105℃ for 4h;

[0131] M2: 33.5 parts of vanadium-titanium magnetite tailings, 11.5 parts of phosphorus tailings, 5 parts of molybdenum tailings, 15 parts of modified siliceous material A prepared in Preparation Example 1, 3 parts of feldspar, 2 parts of dolomite, and 3 parts of bentonite were taken by mass fraction, and the above raw materials were added to water for wet ball milling, with a solid-liquid ratio of 1:1.5, a zirconia ball material and slurry volume ratio of 3:1, a ball milling speed of 300 rpm, and a ball milling time of 10 h. After ball milling, the slurry was sieved through a 200-mesh sieve to remove coarse particles, and a uniform slurry was obtained;

[0132] M3: The uniform slurry was fed into a spray drying device for granulation, with an inlet air temperature of 160°C and an outlet air temperature of 80°C. After drying, the granules were ground and sieved through a 300-mesh sieve to obtain dry powder for molding;

[0133] M4: The powder was loaded into a mold and pressed, with a pre-pressing of 10 MPa for 30 s, followed by a main pressing of 200 MPa for 60 s. The green body was air dried at room temperature for 12 h, and then oven dried at 120°C for 6 h to obtain a molded green body;

[0134] M5: The molded green body was placed in a calcination furnace, heated to 750°C at a rate of 5°C / min, and then stopped heating. The temperature was maintained for 60 min, and then heated to 1150°C at a rate of 5°C / min and maintained for 60 min. After the heat preservation was completed, the temperature was naturally cooled to room temperature to obtain a low water absorption ceramic material.

[0135] Example 6

[0136] Preparation of a low water absorption ceramic material:

[0137] The preparation method was substantially the same as that of Example 1, except that the mass fraction ratio of the organosilicon compounds in the organosilicon precursor solution was different, specifically:

[0138] M5: 8 parts of tetraethoxysilane were dissolved in 72 parts of anhydrous isopropanol, ultrasonically treated for 15 min (frequency 40 kHz, power 300 w), and an organosilicon precursor solution was prepared. The organosilicon precursor solution was placed in an ultrasonic atomizer for use.

[0139] Example 7

[0140] Preparation of a low water absorption ceramic material:

[0141] The preparation method was substantially the same as that of Example 1, except that the mass fraction ratio of the organosilicon compounds in the organosilicon precursor solution was different, specifically:

[0142] M5: 4 parts of tetraethoxysilane and 4 parts of methyltriethoxysilane were dissolved in 72 parts of anhydrous isopropanol, ultrasonically treated for 15 min (frequency 40 kHz, power 300 w), and an organosilicon precursor solution was prepared. The organosilicon precursor solution was placed in an ultrasonic atomizer for use.

[0143] Example 8

[0144] Preparation of low water absorption ceramic material:

[0145] The same as Example 1, except that the modified siliceous material is the modified siliceous material B obtained in Preparation Example 2.

[0146] Example 9

[0147] Preparation of low water absorption ceramic material:

[0148] The same as Example 1, except that the modified siliceous material is the modified siliceous material C obtained in Preparation Example 3.

[0149] Example 10

[0150] Preparation of low water absorption ceramic material:

[0151] The same as Example 1, except that the modified siliceous material is the modified siliceous material D obtained in Preparation Example 4.

[0152] Comparative Example 1

[0153] Preparation of low water absorption ceramic material:

[0154] The same as Example 1, except that the modified siliceous material is the modified siliceous material E obtained in Comparative Preparation Example 1.

[0155] Test section

[0156] Water absorption performance test:

[0157] The ceramic materials obtained in Examples 1-10 and Comparative Example 1 were tested for water absorption, and according to the national standard GB / T 3810.3-2016, the ceramic material was dried to constant weight in an oven at 110°C, then cooled to room temperature in a desiccator with silica gel desiccant, and the weight of the ceramic material was measured and recorded as m1; the ceramic material was placed in a heater containing deionized water, with 5 cm deep water on the upper and lower parts of the material, and the water level was kept above the ceramic material by 5 cm throughout the test; the water was heated to boiling and kept boiling for 2 h, then the heat source was turned off, the brick was completely soaked in water and cooled to room temperature, and kept for 4 h; a piece of wetted suede was wrung by hand, and the suede was placed on the platform to gently wipe the surface of the ceramic material, then the weight of the ceramic material was measured and recorded as m2, and the water absorption E b The calculation formula is as follows:

[0158] 1 00%

[0159] The test results are shown in Table 1.

[0160] Table 1 Water absorption test

[0161]

[0162] According to Table 1, the ceramic material obtained in each example has a lower water absorption than Comparative Example 1, indicating that the ceramic material provided in the present application has good hydrophobicity. The reason may be that the modified siliceous material in Comparative Example 1 lacks a silica network structure coated on the surface of the siliceous material, which may weaken the anchoring of the apatite particles, and the apatite particles may easily agglomerate during high-temperature sintering, which cannot effectively fill the fine pores. In addition, the migration of apatite may also weaken its self-healing function, thereby reducing the density of the material. Moreover, the lack of a silica network may also lead to a decrease in interfacial bonding strength, and the capillary channels in the material may be more easily connected, resulting in an increase in water absorption.

[0163] According to Examples 1 and 2, the type of tailings added to the raw material has a certain influence on the water absorption of the ceramic material. When molybdenum tailings are introduced into vanadium-titanium magnetite tailings and phosphorus tailings, the ceramic material has a lower water absorption.

[0164] According to Examples 1, 3-4, the mass fraction ratio of tailings added to the raw material has a certain influence on the water absorption of the ceramic material. When the mass fraction ratio of vanadium-titanium magnetite tailings and molybdenum tailings in the metal tailings is kept constant, and the mass fraction ratio of metal tailings and non-metal tailings is 10:2.5-3.5, the ceramic material has a lower water absorption.

[0165] According to Examples 1 and 5, the treatment during the firing stage has a certain influence on the water absorption of the ceramic material. When an atmosphere containing an organosilicon compound is introduced into the furnace, the ceramic material has a lower water absorption.

[0166] According to Examples 1, 6, and 7, the composition ratio of the organosilicon compound introduced into the furnace during the firing stage has a certain influence on the water absorption of the ceramic material. When the organosilicon compound is composed of tetraethoxysilane and methyltriethoxysilane in a mass fraction ratio of 6:1.5-2.5, the ceramic material has a lower water absorption.

[0167] According to Examples 1 and 8, in the apatite / silica composite layer coated on the surface of the siliceous material in the modified siliceous material, the type of apatite has a certain influence on the water absorption of the ceramic material. When fluorohydroxyapatite is contained, the ceramic material has a lower water absorption.

[0168] According to the embodiments 1 and 9, in the modified siliceous material, the groups existing in the silica network in the apatite / silica composite layer coated on the surface of the siliceous material have certain influence on the water absorption of the ceramic material, and the water absorption of the ceramic material is lower when the groups contain methyl groups.

[0169] According to the embodiments 1 and 10, in the modified siliceous material, the type of the siliceous material has certain influence on the water absorption of the ceramic material, and the water absorption of the ceramic material is lower when the siliceous material is a combination of pearl stone and silica ash.

[0170] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application, but not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement for part or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A low-absorption ceramic material, characterized in that, Includes the following quantities of raw materials: 50 parts tailings, 10-25 parts modified siliceous material, 2-8 parts flux, 1-5 parts binder; The modified siliceous material includes a siliceous material and an apatite / silica composite layer coated on the surface of the siliceous material; the apatite / silica composite layer includes apatite particles and a silicon-oxygen network formed by curing silica sol.

2. The low water absorption ceramic material according to claim 1, characterized in that, The tailings include metallic tailings and non-metallic tailings, with a mass ratio of metallic tailings to non-metallic tailings of 10:2.5~3.

5. The metallic tailings include vanadium-titanium magnetite tailings, and the non-metallic tailings include phosphorus tailings.

3. The low water absorption ceramic material according to claim 2, characterized in that, The metal tailings also include molybdenum tailings, wherein the mass ratio of vanadium-titanium magnetite tailings to molybdenum tailings is 10:1~2.

4. The low water absorption ceramic material according to claim 1, characterized in that, The preparation method of the modified silica material includes the following steps: S1: Activate the silicon material by placing it in an alkaline solution; S2: The activated silicon material is treated in a solution containing an aminosilane coupling agent to form amino-containing organosilicon anchoring points on the surface of the silicon material. S3: Immerse the siliceous material with amino groups on its surface in a solution containing calcium salts to allow the amino end groups to combine with calcium ions; then transfer it to a solution containing phosphates and adjust the pH to 7-8 to allow apatite to be deposited in situ on the surface of the siliceous material. S4: Disperse the silica material with apatite particles on the surface in silica sol to form a silica gel network on the surface of the apatite particles and silica material. S5: Calcining is performed on the silica material with a silica gel network and apatite particles on the surface to remove organic residues and solidify the silica network, resulting in a modified silica material with an apatite / silica composite layer on the surface.

5. The low water absorption ceramic material according to claim 4, characterized in that, At least one of the following conditions must be met: 1) The siliceous material includes perlite and silica fume, wherein the mass ratio of perlite to silica fume is 2:0.5~1.5; 2) The aminosilane coupling agent includes 3-aminopropyltriethoxysilane; 3) The phosphate-containing solution also includes fluoride, wherein the fluoride includes ammonium fluoride; 4) The silica sol is prepared using at least one of tetraethoxysilane and methyltrimethoxysilane as the silicon source.

6. The low water absorption ceramic material according to claim 5, characterized in that, The preparation method of the modified silica material includes the following steps: S1: Mix 15 parts perlite and 8-11 parts silica fume and place them in an aqueous solution of NH4OH. Activate at 60-80℃ for 10-60 min. The molar concentration of NH4OH is 0.04-0.06 mol / L. S2: The activated silica material is dispersed in a 0.5-1.5 wt% aqueous / ethanol solution of 3-aminopropyltriethoxysilane and reacted at 60-80 °C for 1-2 h to obtain NH2-silica material; S3: Immerse the NH2-silica material in a solution containing calcium salts, with a calcium molar concentration of 0.1~0.2 mol / L, and stir for 1~2 h; then transfer it to a solution containing phosphate and fluoride, with a phosphorus molar concentration of 0.05~0.1 mol / L and a fluoride molar concentration of 1~2 mmol / L, add 0.25~0.35 mol / L urea aqueous solution to adjust the pH to 7~8, and age for 1~2 h to obtain apatite / silica material; S4: Tetraethoxysilane, methyltrimethoxysilane, water and ethanol are prepared in a mass ratio of 10:1~2:20~40:40~80 to obtain a silica sol. After aging for 1~2 hours, apatite / silica material is placed in the silica sol, ultrasonicated and impregnated to form a silica gel network on the surface of the material. S5: Calcine the silica material with a silica gel network and apatite particles on the surface at 400~700℃ for 20~60min to remove organic residues and solidify the silica network, to obtain a modified silica material with an apatite / silica composite layer on the surface.

7. The low-absorption ceramic material according to any one of claims 1 to 6, characterized in that, The raw materials meet at least one of the following conditions: 1) The flux includes at least one of feldspar, dolomite, talc, and waste glass powder; 2) The binder includes at least one of kaolin, bentonite, polyvinyl alcohol, and carboxymethyl cellulose.

8. A method for preparing a low-water-absorption ceramic material, characterized in that, include: Provide the raw material of the low water absorption ceramic material according to any one of claims 1 to 7, add water to the raw material and perform wet ball milling to obtain a slurry, dry and granulate it and then press it to obtain a green body; The green body is fired to obtain a low water absorption ceramic material.

9. The preparation method according to claim 8, characterized in that, The conditions for the firing process include: The green billet is placed in a calcining furnace. First, the furnace temperature is raised to 700~900℃ in an oxygen-containing atmosphere. Then, it is held at 700~900℃ for 50~100 minutes in an inert atmosphere containing atomized organosilicon compounds. Next, the furnace temperature is raised to 1100~1200℃ in an oxygen-containing atmosphere and held for 30~120 minutes. The injection rate of the atomized organosilicon compound is 0.1~0.5 mL / min.

10. The preparation method according to claim 9, characterized in that, The atomized organosilicon compound includes tetraethoxysilane and methyltriethoxysilane, wherein the mass ratio of tetraethoxysilane to methyltriethoxysilane is 6:1.5~2.5.

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