Ceramic green body, ceramic body, ceramic tile and preparation method based on desulfurized lithium slag and calcined sludge

Abstract

The application provides a ceramic blank based on desulfurization lithium slag and calcined sludge, a ceramic body, a ceramic tile and a preparation method, and the ceramic blank comprises, in terms of dry basis weight percentage, 5-10% of bentonite, 1-3% of modified starch, 20-35% of calcined sludge, 20-35% of desulfurization lithium slag, 25-35% of high-boron clinker and 0.3-1.0% of a peptizing agent. The application can make the lithium slag and the sludge be more reasonably applied by mixing the desulfurization lithium slag and the calcined sludge, and the problems such as the influence of high sulfate content in the lithium slag raw material on the ceramic product quality and the influence of the lithium slag raw material mixed into the blank on the slurry fluidity are solved, and the influence of the organic component impurities in the sludge raw material on the ceramic product quality is solved.

Description

Technical Field

[0001] This invention relates to the field of ceramic production technology, and in particular to ceramic raw materials, ceramic bodies, ceramic bricks, and preparation methods based on desulfurized lithium slag and calcined sludge. Background Technology

[0002] With the rapid development of the new energy industry, the amount of solid waste generated by the lithium battery industry has increased dramatically. Statistics show that producing one ton of lithium carbonate produces approximately 8-10 tons of lithium slag. The large accumulation of lithium slag not only occupies land but also poses a threat to soil, water, and air quality. Meanwhile, sludge, an inevitable byproduct of wastewater treatment, is rich in pollutants. Improper disposal can cause serious secondary pollution. Therefore, promoting the harmless treatment and resource utilization of sludge is crucial to avoiding secondary pollution and preserving the achievements of water pollution control. In other words, existing technologies are not effectively treating the large accumulation of lithium slag and sludge.

[0003] Therefore, existing technologies have shortcomings and need to be improved and developed. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide ceramic blanks, ceramic bodies, ceramic bricks and preparation methods based on desulfurized lithium slag and calcined sludge, in order to address the above-mentioned defects of the prior art.

[0005] The technical solution adopted by this invention to solve the technical problem is as follows: The first aspect of this application provides a ceramic blank based on desulfurized lithium slag and calcined sludge, wherein the ceramic blank comprises, by dry weight percentage: 5-10% bentonite, 1-3% modified starch, 20-35% calcined sludge, 20-35% desulfurized lithium slag, 25-35% high boron frit, and 0.3-1.0% degumming agent.

[0006] In one embodiment of this application, the chemical composition of the ceramic blank, by weight percentage, includes: SiO2 40-50%, Al2O3 15-20%, K2O 1.8-2.5%, Na2O 3.5-5.5%, CaO 3.5-5.5%, MgO 0.3-1.0%, Fe2O3 3.5-7.5%, BaO 2.65-3.85%, B2O3 6.3-9.5%, ZnO 0.5-1.5%, P2O5 3.5-5.5%, Loss on ignition 4.5-5.5%.

[0007] In one embodiment of this application, the chemical composition of the high-boron frit, by weight percentage, includes: The composition of the ingredients is as follows: SiO2 40-50%, Al2O3 1-5%, CaO 1-2%, MgO 0.1-0.5%, K2O 0.5-1.5%, Na2O 5-10%, B2O3 18-28%, ZnO 1-5%, BaO 5-12%, and loss on ignition 0.5-2.5%.

[0008] In one embodiment of this application, the desulfurized lithium slag is obtained by reducing the sulfur content in the lithium slag raw material to 1.8-3.0% through a flotation desulfurization process; the calcined sludge is obtained by calcining the sludge raw material at a temperature of 900-950℃.

[0009] A second aspect of this application provides a ceramic green body, which is prepared using ceramic raw materials based on desulfurized lithium slag and calcined sludge as described above.

[0010] The third aspect of this application provides a method for preparing a ceramic green body, including: The following ingredients are mixed by dry weight percentage: 5-10% bentonite, 1-3% modified starch, 20-35% calcined sludge, 20-35% desulfurized lithium slag, 25-35% high boron frit, and 0.3-1.0% degumming agent to obtain the mixed raw materials. The mixed raw materials are ball-milled to obtain a slurry, and the slurry is spray-dried to obtain a powder. The powder is dry-pressed to form a ceramic blank.

[0011] In one embodiment of this application, the moisture content of the powder is controlled at 6.8-7.2%, and the dry strength of the ceramic green body obtained after drying is 1.2MPa-1.8MPa.

[0012] The fourth aspect of this application provides a method for preparing ceramic bricks, including: The ceramic green body prepared by the ceramic green body preparation method described above and / or the ceramic green body preparation method described above is dried to obtain a dry green body; A low-temperature glaze is applied to the surface of the dry blank, and surface decoration is performed to obtain a glazed blank; After drying, the glazed blank is fired in a kiln at a temperature of 700℃~750℃ for 35~50 minutes to obtain ceramic bricks. The ceramic brick has a water absorption rate of less than 3.0% and a modulus of rupture of greater than 40 MPa.

[0013] In one embodiment of this application, the raw materials of the low-temperature glaze, by weight, include: Kaolin 5-10 parts, potassium feldspar 10-15 parts, calcined talc 0-5 parts, zirconium silicate 0-5 parts, high boron frit 75-85 parts, sodium tripolyphosphate 0.3-0.5 parts, carboxymethyl cellulose 0.1-0.2 parts; The chemical composition of the low-temperature glaze, by weight percentage, includes: The composition is as follows: SiO2 45-55%, Al2O3 5-10%, Na2O 5-8%, K2O 1.5-2.5%, CaO 1-3%, MgO 0.5-2.5%, Fe2O3 0.15-0.3%, B2O3 15-25%, ZnO 1-4.5%, BaO 4.5-10%, and loss on ignition 1.5-3.5%.

[0014] The fifth aspect of this application provides a ceramic tile, which is prepared by the ceramic tile preparation method described above.

[0015] The present invention achieves the following beneficial effects: This invention provides ceramic blanks, ceramic bodies, ceramic bricks, and preparation methods based on desulfurized lithium slag and calcined sludge. The ceramic blanks, by dry weight percentage, comprise: 5-10% bentonite, 1-3% modified starch, 20-35% calcined sludge, 20-35% desulfurized lithium slag, 25-35% high-boron frit, and 0.3-1.0% desizing agent. By incorporating desulfurized lithium slag and calcined sludge, this application enables more rational application of lithium slag and sludge, avoiding excessive accumulation. Furthermore, it solves the problems of high sulfate content in lithium slag raw materials affecting ceramic product quality and the impact of lithium slag raw materials on slurry fluidity when incorporated into the blank, as well as the impact of the high organic content of sludge raw materials on ceramic product quality. The synergistic effect of lithium slag, sludge, and high-boron frit, utilizing ultra-low temperature conditions to form a reinforcement mode with acicular anorthite as the main crystalline phase, changes the traditional blank system's reinforcement structure based on acicular mullite as the main crystalline phase. Attached Figure Description

[0016] Figure 1 This is a flowchart of a preferred embodiment of the ceramic body preparation method in this invention.

[0017] Figure 2 This is a process flowchart for preparing ceramic bricks in this invention. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of this invention clearer and more explicit, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0019] As a traditional high-energy-consuming industry, the building ceramics industry urgently needs to transform towards a green and low-carbon direction. Therefore, using solid waste such as lithium slag and sludge in ceramic production can achieve "treating waste with waste and turning waste into treasure", which has important environmental and economic value.

[0020] This application utilizes lithium tailings and sludge as raw materials for ceramic bodies. The lithium tailings are rich in SiO2 (40%–55%) and Al2O3 (15%–25%), and contain abundant K2O, Na2O, CaO, MgO, and other medium- and low-temperature fluxes, exhibiting certain pozzolanic activity and fluxing effects. Simultaneously, the combination with the strong flux P2O5 (approximately 12%) contained in the sludge helps to lower the firing temperature of the ceramic body, for example, reducing it to below 750℃. This application not only economically reduces ceramic production costs and decreases the consumption of natural resources, but also improves the comprehensive utilization rate of solid waste, mitigates its environmental pollution, promotes the green production of ceramic tiles, and contributes to accelerating the comprehensive green transformation of economic and social development.

[0021] This invention mainly solves the following problems: First, this invention solves the problems of high and varied organic matter content in sludge affecting the dispersibility of the sludge during wet ball milling of ceramic raw materials, and the defects such as bulging and pinholes caused by decomposition and gas release during high-temperature firing. By pre-treating the sludge with high-temperature calcination and adjusting the ceramic formula and firing process, the problems of poor sludge fluidity and product defects caused by organic matter decomposition are resolved.

[0022] Secondly, this invention improves the problem of lithium slag desulfurization by flotation, which reduces the sulfur content in lithium slag to ≤3%. This addresses the issues of the impact on slurry performance during wet ball milling of raw materials when lithium slag is incorporated into billets, the corrosion of kiln furniture by sulfides during high-temperature firing, and the impact of harmful gases emitted on the air environment. This broadens the application range of lithium slag and enables more rational utilization of solid waste raw materials.

[0023] Third, this invention utilizes the CaO, K2O, and Na2O in lithium slag, the B2O3, ZnO, and BaO in high-boron fused blocks, and the high P2O5 content in sludge to achieve an ultra-low temperature fluxing system. This system forms a reinforcement mode with acicular anorthite as the main crystalline phase under ultra-low temperature conditions below 750℃, changing the traditional billet system's structure that relies on acicular mullite as the main crystalline phase for reinforcement, and creating a new building ceramic billet system.

[0024] This invention prepares ultra-low temperature building ceramic products with a firing temperature below 750℃, a firing cycle of 35-50 minutes, a water absorption rate of less than 3.0%, and a rupture modulus greater than 40MPa by incorporating a large amount of desulfurized lithium slag, calcined sludge, low-temperature flux (high boron frit), clay, and other raw materials into the ceramic blank. These products meet the building materials industry standards for ceramic wall tiles and ceramic floor tiles, while simultaneously achieving energy conservation, emission reduction, and green production.

[0025] This invention provides a ceramic blank based on desulfurized lithium slag and calcined sludge. The ceramic blank, by dry weight percentage, comprises: 5-10% bentonite, 1-3% modified starch, 20-35% calcined sludge, 20-35% desulfurized lithium slag, 25-35% high boron frit, and 0.3-1.0% degelatinizing agent.

[0026] Specifically, bentonite and modified starch together provide the green body with the required green body strength. This application utilizes the high strength and strong plasticity of bentonite and starch to replace kaolin-type clay with high loss on ignition, thereby reducing defects such as bubbles and pinholes caused by excessive loss on ignition during the firing process, while greatly reducing the amount of clay used due to the increasingly depleted mineral resources.

[0027] Furthermore, the desulfurized lithium slag used in this application is obtained by pre-treating lithium slag raw materials, which solves the problems of high sulfate content in lithium slag raw materials affecting the quality of ceramic products and the impact of lithium slag raw materials on the fluidity of slurry when incorporated into the billet. This allows lithium slag to be used in a large proportion of the production of building ceramic products, reducing the environmental hazards caused by lithium slag stockpiling.

[0028] The calcined sludge used in this application is obtained by pre-treating sludge raw materials. This solves the problem of the impact of the mixed organic components of sludge raw materials on slurry performance and ceramic product quality, enabling more rational use of urban solid waste, increasing the added value of sludge, and reducing the pollution caused by sludge to the urban environment.

[0029] This application develops a formulation system for preparing ultra-low temperature ceramic green bodies by combining lithium slag, sludge, and high-boron frit. It utilizes the reinforcement method formed under ultra-low temperature conditions with acicular calcium feldspar as the main crystalline phase, thereby changing the traditional green body system which uses acicular mullite as the main crystalline phase for reinforcement and creating a new building ceramic green body system.

[0030] For example, the degumming agent includes one or more of sodium tripolyphosphate, sodium hexametaphosphate, sodium humate, liquid degumming agents (such as water glass), etc.

[0031] In this embodiment of the application, the chemical composition of the ceramic blank, by weight percentage, includes: SiO2 40-50%, Al2O3 15-20%, K2O 1.8-2.5%, Na2O 3.5-5.5%, CaO 3.5-5.5%, MgO 0.3-1.0%, Fe2O3 3.5-7.5%, BaO 2.65-3.85%, B2O3 6.3-9.5%, ZnO 0.5-1.5%, P2O5 3.5-5.5%, Loss on ignition 4.5-5.5%.

[0032] This application utilizes the high Al2O3 content in sludge to provide the network structure required for the green body skeleton, thereby increasing the strength of ceramic bricks; the high P2O5 content and the high boron frit synergistic fluxing provide a solid foundation for the ultra-low temperature ceramic green body system, realizing the application of sludge in ultra-low temperature building ceramic green bodies.

[0033] For example, the chemical composition of the desulfurized lithium slag, by weight percentage, includes: The composition is as follows: SiO2 44.27%, Al2O3 24.18%, K2O 5.60%, Na2O 2.11%, CaO 12.55%, MgO 0.88%, Fe2O3 2.81%, loss on ignition 3.51%, with the balance being impurities.

[0034] The total content of SiO2 and Al2O3 in desulfurized lithium slag is close to 70%, which provides the necessary aluminum-silicon framework for the ceramic green body. These crystalline particles act as a framework during sintering, being encapsulated by the liquid phase generated by the high-boron frit, effectively preventing excessive softening and deformation of the green body at high temperatures. Simultaneously, the alkaline oxide components such as K2O, Na2O, and CaO contained in the desulfurized lithium slag also have a certain fluxing effect, synergistically lowering the sintering temperature with the high-boron frit. Of particular concern is the potential for sulfates in the desulfurized lithium slag to generate gas during high-temperature decomposition. Improper control can easily lead to defects such as bulges and pinholes in the green body. The solution proposed in this application is to utilize the sufficient liquid phase generated by the high-boron frit under ultra-low temperature sintering conditions, allowing the gas generated by sulfate decomposition to escape smoothly. Simultaneously, the liquid phase of the high-boron frit can quickly fill the voids created by sulfate decomposition, thereby preventing defects such as bubbles, pinholes, and black cores in the green body.

[0035] For example, the chemical composition of the calcined sludge, by weight percentage, includes: SiO2 32.91%, Al2O3 31.54%, K2O 1.9%, Na2O 0.53%, CaO 0.72%, MgO 0.82%, Fe2O3 17.34%, P2O5 11.99%, Loss on ignition 2.25%.

[0036] The Fe2O3 and P2O5 contents are relatively high, reaching 17.34% and 11.99% respectively. During the sintering stage, Fe2O3 can function as a mineralizer, promoting the crystallization process and liquid-phase mass transfer, thereby accelerating the densification of the material. In addition, Fe2O3 and P2O5 can disrupt the silicon-oxygen network to a certain extent, helping to lower the glass transition temperature and thus contributing to a reduction in the system's glass transition temperature. Together with B2O3 in the high-boron fused block and network-modifying components such as Na2O and ZnO in the billet, they construct a multi-element eutectic system, significantly reducing the initial melting temperature of the billet and generating a large amount of low-viscosity glass phase in the 700℃ to 750℃ range. The generated glass phase can act as a medium for interparticle mass transfer and reacts with silica, alumina, etc. in the billet during heating, promoting the formation of low-temperature crystalline phases such as anorthite. The newly precipitated crystals can interweave to form a skeletal structure, thereby significantly improving the mechanical strength of the billet and effectively overcoming strength defects that may be caused by insufficient ultra-low temperature sintering.

[0037] This invention, through compositional analysis of lithium slag and sludge raw materials, utilizes the high Al2O3 content and abundant fluxing agents (K2O, Na2O, CaO) in lithium slag, combined with the high Al2O3 and P2O5 content in sludge, and incorporates a high-boron frit, to prepare building ceramic products that can be fired at ultra-low temperatures below 750℃. The products exhibit a water absorption rate of less than 3.0% and a modulus of rupture greater than 40MPa. While consuming large amounts of industrial waste and municipal solid waste, this significantly reduces the firing temperature of building ceramic bricks, achieving energy conservation and emission reduction, and realizing the green development of the ceramic industry.

[0038] In one embodiment of this application, the chemical composition of the high-boron frit, by weight percentage, includes: The composition of the ingredients is as follows: SiO2 40-50%, Al2O3 1-5%, CaO 1-2%, MgO 0.1-0.5%, K2O 0.5-1.5%, Na2O 5-10%, B2O3 18-28%, ZnO 1-5%, BaO 5-12%, and loss on ignition 0.5-2.5%.

[0039] Specifically, high-boron frit is the core flux for achieving ultra-low temperature sintering. B2O3 effectively breaks down the high-melting-point silicon-oxygen network in the billet, significantly reducing the temperature at which the liquid phase appears. Its introduction can drastically lower the eutectic point of the billet to the 600-800°C range, laying a solid foundation for the formation of a sufficient liquid phase below 750°C. It can optimize the physical properties of the high-temperature melt, reducing viscosity and surface tension, and promoting billet densification in ultra-low temperature environments. This ensures the smooth removal of bubbles and uniform shrinkage of the billet, effectively preventing deformation and cracking. The ZnO, Na2O, K2O, and BaO components in the frit can synergistically work with B2O3 to further broaden the sintering temperature range and improve process stability.

[0040] For example, the chemical composition of the high-boron frit, by weight percentage, mainly includes: SiO2 44.81%, Al2O3 2.8%, K2O 0.98%, Na2O 9.03%, CaO 1.66%, MgO 0.13%, Fe2O3 0.15%, BaO 9.71%, B2O3 23.42%, ZnO 4.34%, Loss on ignition 1.06%.

[0041] In the embodiments of this application, the desulfurized lithium slag is obtained by reducing the sulfur content in the lithium slag raw material to 1.8~3.0% through a flotation desulfurization process; the calcined sludge is obtained by calcining the sludge raw material at a temperature of 900~950℃.

[0042] For example, the flotation desulfurization process involves adjusting the pH value and adding collectors, inhibitors, foaming agents, and other components to form a flotation agent. This process reduces the sulfur content in lithium slag from 10.38% to 2.98%, thereby improving the slurry properties during wet ball milling of the billet, reducing the amount of deflocculant required, and avoiding the impact of sulfides on the kiln and the environment. It provides abundant fluxing agents for ultra-low temperature ceramic billets. The 12.55% CaO content in the lithium slag is the main source of the formation of the anorthite crystalline phase at firing temperatures below 750℃.

[0043] The purpose of calcining sludge at 900~950℃ is to remove a large amount of mixed organic matter, improve the properties of the sludge, prevent defects such as pores and black cores caused by incomplete combustion during the final sintering process of the green body, ensure product quality and environmental safety, and more importantly, to modify the material form, fix key components, activate chemical activity, and create favorable conditions for the final low-temperature sintering.

[0044] In one embodiment, the lithium slag is pretreated. For example, the sulfur content of the undesulfurized lithium slag is 5%~15%, and the fineness of the lithium slag is controlled to D50 of 20-50µm. The material-to-water ratio of the lithium slag slurry is 1:2. Desulfurization is carried out using a flotation process with a hydroxamic acid oxidant. The process involves three scavenging steps: First, the amount of hydroxamic acid oxidant added is 0.03% of the weight of the lithium slag, stirred for 5 minutes, and then skimmed (i.e., water rinsing and filtration). Second, the amount of hydroxamic acid oxidant added is 0.01% of the weight of the lithium slag, stirred for 5 minutes, and then skimmed. Third, the amount of hydroxamic acid oxidant added is 0.005% of the weight of the lithium slag, stirred for 5 minutes, and then skimmed. The dehydrated lithium slag is then dried to obtain the treated lithium slag with a sulfur content of 1.8%~3.0%, which is the desulfurized lithium slag, used for billet preparation.

[0045] In one embodiment, the sludge is pretreated by dewatering and then calcined at 950°C to remove numerous and complex organic substances, modify the material morphology, fix key components, and activate chemical activity, creating favorable conditions for low-temperature sintering. The calcined sludge is then crushed and used for billet preparation.

[0046] This application improves the performance of the slurry obtained by wet ball milling of lithium slag after it is incorporated into the billet by flotation desulfurization. It utilizes the rich chemical components required for ceramic billet made from lithium slag to realize the application of lithium slag in building ceramic billet making, so as to make fuller use of mineral resources and solve the problems of lithium slag stockpiling and environmental pollution. Furthermore, by calcining sludge at high temperature, the application removes the abundant and mixed organic matter in the sludge, improves the performance of the slurry obtained by wet ball milling of sludge after it is incorporated into the billet, so as to make rational use of urban solid waste and solve the problem of sludge pollution to the natural environment.

[0047] This application also provides a ceramic green body, which is prepared using ceramic green bodies based on desulfurized lithium slag and calcined sludge as described above.

[0048] like Figure 1 As shown, this application also provides a method for preparing a ceramic green body, comprising: Step S100: Mix 5-10% bentonite, 1-3% modified starch, 20-35% calcined sludge, 20-35% desulfurized lithium slag, 25-35% high boron frit, and 0.3-1.0% degumming agent by dry weight percentage to obtain mixed raw materials; Step S200: The mixed raw materials are ball-milled to obtain a slurry, and the slurry is spray-dried to obtain powder. Step S300: The powder is dry-pressed to form a ceramic blank.

[0049] For example, before step S100, the raw materials are aged and homogenized. Hard raw materials need to be crushed first to improve the efficiency and accuracy of wet ball milling. The coarse crushing fineness D50 of the raw materials is controlled between 20µm and 50µm. In step S100, according to the moisture content of each raw material and the percentage of each raw material in the formula design, a belt feeder is used to accurately convey the batched raw materials into the ball mill. In step S200, the raw materials are wet ball milled to obtain a formula slurry that meets the fineness requirements. The slurry is then sieved, iron removed, and aged. The wet ball milling fineness of the slurry is controlled to have a residue of 1.8% to 2.4% on a 250-mesh sieve.

[0050] This application describes a formulation system and process for preparing ultra-low temperature ceramic green bodies from lithium slag, sludge, and high-boron frit. By utilizing the reinforcement method formed under ultra-low temperature conditions with acicular calcium feldspar as the main crystalline phase, it changes the traditional green body system which uses acicular mullite as the main crystalline phase for reinforcement, and creates a new building ceramic green body system.

[0051] In one embodiment of this application, the moisture content of the powder is controlled at 6.8-7.2%, and the dry strength of the ceramic green body obtained after drying is 1.2MPa-1.8MPa.

[0052] This application controls the moisture content of the powder to 6.8-7.2%, which makes the green body uniform in density and reduces deformation and cracking; the dry green body strength is 1.2MPa-1.8MPa, which can ensure processing operation and prevent the formation of pores, black core and abnormal strength after sintering due to excessive binder and additives.

[0053] This application also provides a method for preparing ceramic bricks, including: The ceramic green body prepared by the ceramic green body preparation method described above and / or the ceramic green body preparation method described above is dried to obtain a dry green body; A low-temperature glaze is applied to the surface of the dry blank, and surface decoration is performed to obtain a glazed blank; After drying, the glazed blank is fired in a kiln at a temperature of 700℃~750℃ for 35~50 minutes to obtain ceramic bricks. The ceramic brick has a water absorption rate of less than 3.0% and a modulus of rupture of greater than 40 MPa.

[0054] Specifically, the main process route of the present invention is as follows: raw material processing (lithium slag and sludge pretreatment) → green body formula design → batching → green body processing → spray drying powder making → pressing and molding → glazing → surface decoration (inkjet printing) → firing.

[0055] For example, after the surface glazing process is completed, the green body is dried and then fired in a roller kiln at a temperature of 700℃~750℃ for 35~50 minutes to produce a semi-finished product. The semi-finished product after leaving the kiln is ground, air-dried, inspected, sorted by color, graded and stored. The finished product has a water absorption rate of less than 3.0% and a modulus of rupture of greater than 40MPa.

[0056] This invention utilizes a multi-element fluxing method, combining B2O3 from high-boron frit, CaO, K2O, and Na2O from lithium slag, and P2O5 from sludge. Through green body formulation adjustments, it produces ceramic products with firing temperatures significantly lower than conventional building ceramics, achieving a ceramic green body formulation system with a firing temperature below 750℃. The product exhibits a water absorption rate of less than 3.0%, a modulus of rupture greater than 40 MPa, and other properties meeting national standards for building ceramics. While consuming large amounts of industrial waste and municipal solid waste, it significantly reduces the firing temperature of building ceramic bricks, achieving energy conservation and emission reduction, lowering green body and production costs, and realizing green development in the ceramic industry.

[0057] In this embodiment of the application, the raw materials of the low-temperature glaze, by weight, include: Kaolin 5-10 parts, potassium feldspar 10-15 parts, calcined talc 0-5 parts, zirconium silicate 0-5 parts, high boron frit 75-85 parts, sodium tripolyphosphate 0.3-0.5 parts, carboxymethyl cellulose 0.1-0.2 parts; The chemical composition of the low-temperature glaze, by weight percentage, includes: The composition is as follows: SiO2 45-55%, Al2O3 5-10%, Na2O 5-8%, K2O 1.5-2.5%, CaO 1-3%, MgO 0.5-2.5%, Fe2O3 0.15-0.3%, B2O3 15-25%, ZnO 1-4.5%, BaO 4.5-10%, and loss on ignition 1.5-3.5%.

[0058] This application develops a low-temperature glaze formulation that matches the ultra-low temperature ceramic body formulation system. The high-boron frit in the low-temperature glaze formulation is the same as the high-boron frit used in the ceramic body formulation.

[0059] For example, the specific gravity of the low-temperature glaze is controlled at 1.55 to 1.65, the glaze amount (for a 300×300mm plate) is 35 to 45g, and the fineness of the low-temperature glaze is controlled at 0.3 to 0.5% (residue on a 325-mesh sieve).

[0060] This application develops a low-temperature glaze formula that matches the ultra-low temperature ceramic body system, enabling the glaze layer obtained from the glaze to adapt to the low-temperature environment, thereby producing high-performance ceramic tile products.

[0061] This application also provides a ceramic tile, wherein the ceramic tile is prepared by the ceramic tile preparation method described above.

[0062] The following are specific examples for illustration.

[0063] Example 1: The ceramic blanks in this case, calculated as a percentage by dry weight, include: Bentonite 7%, modified starch 2%, calcined sludge 25%, desulfurized lithium slag 35%, high boron frit 30%, and degumming agent 1.0%.

[0064] The chemical composition of the above blank formulation consists of the following components by weight percentage: SiO2 42.83%, Al2O3 17.83%, K2O 2.2%, Na2O 4.69%, CaO 4.06%, MgO 0.52%, Fe2O3 6.69%, BaO 3.65%, B2O3 7.69%, ZnO 1.37%, P2O5 4.19%, Loss on ignition 4.28%.

[0065] The ceramic brick preparation method in this embodiment includes: Step A1: Lithium Slag Pretreatment: The sulfur content of the undesulfurized lithium slag is 10.38%. The fineness of the lithium slag is controlled to D50 of 20-50µm; the ratio of material to water in the lithium slag slurry is 1:2. Desulfurization is carried out using a flotation process with a hydroxamic acid oxidant. The process involves three scavenging stages: First, the amount of hydroxamic acid oxidant added is 0.03% of the weight of the lithium slag, stirred for 5 minutes, and foam is skimmed off. Second, the amount of hydroxamic acid oxidant added is 0.01% of the weight of the lithium slag, stirred for 5 minutes, and foam is skimmed off. Third, the amount of hydroxamic acid oxidant added is 0.005% of the weight of the lithium slag, stirred for 5 minutes, and foam is skimmed off. The dehydrated lithium slag is dried to obtain the treated lithium slag with a sulfur content of 2.98%, which is the desulfurized lithium slag, used for billet preparation.

[0066] Step A2, Sludge Pretreatment: After dewatering, the sludge is calcined at 900℃ to remove the abundant and complex organic matter, modify its morphology, fix key components, and activate its chemical activity, creating favorable conditions for low-temperature sintering. The calcined sludge is then crushed and used for billet preparation.

[0067] Step A3: The raw materials are aged and homogenized. Hard raw materials need to be crushed first to improve the efficiency and accuracy of wet ball milling. The coarse crushing fineness D50 of the raw materials is controlled at 20µm~50µm.

[0068] Step A4: Ingredient batching. Based on the moisture content of each raw material and the percentage of each raw material in the formula design, a belt feeder is used to accurately convey the batched raw materials to the ball mill.

[0069] Step A5: The raw materials are wet ball milled to obtain a formula slurry that meets the fineness requirements. The slurry is then sieved, iron removed, and aged. The fineness of the wet ball milling of the slurry is controlled to be 1.8% to 2.2% residue on a 250-mesh sieve.

[0070] Step A6: After the powder is prepared by spray drying, it is dry pressed to obtain a ceramic green body. The moisture content of the powder is controlled at 6.8%~7.2% and the dry body strength is 1.45MPa.

[0071] Step A7: After the green body with low-temperature glaze is dried, it is fired in a roller kiln at a temperature of 745℃ for 49 minutes to produce a semi-finished product. The semi-finished product after leaving the kiln is ground, air-dried, inspected, sorted by color, graded, and stored. The finished product has a water absorption rate of 2.43% and a modulus of rupture of 41MPa.

[0072] In this embodiment, the raw materials for the low-temperature glaze, by weight, include: 8 parts kaolin, 10 parts potassium feldspar, 3 parts calcined talc, 2.4 parts zirconium silicate, 76 parts high boron frit, 0.5 parts sodium tripolyphosphate, and 0.1 parts CMC.

[0073] The high-boron frit in the low-temperature glaze is the same as the high-boron frit used in the body formulation.

[0074] The chemical composition of the low-temperature glaze, by weight percentage, includes: SiO2 49.7%, Al2O3 7.3%, Na2O 7.15%, K2O 2.25%, CaO 1.55%, MgO 0.75%, Fe2O3 0.23%, B2O3 17.82%, ZnO 3.3%, BaO 7.45%, Loss on ignition 2.5%.

[0075] In this embodiment, the specific gravity of the low-temperature glaze is controlled at 1.58 to 1.65, the glaze amount (for a 300×300mm plate) is 40g, and the fineness of the low-temperature glaze is controlled at 0.45% (residue on a 325-mesh sieve).

[0076] Example 2: The ceramic blanks in this case, calculated as a percentage by dry weight, include: Bentonite 7%, modified starch 2%, calcined sludge 20%, desulfurized lithium slag 40%, high boron frit 30%, and degumming agent 1.0%.

[0077] The chemical composition of the above-mentioned material formula consists of the following components by weight percentage: SiO2 44.05%, Al2O3 19.37%, K2O 2.45%, Na2O 4.82%, CaO 4.53%, MgO 0.35%, Fe2O3 5.58%, BaO 3.53%, B2O3 7.25%, ZnO 1.24%, P2O5 3.85%, Loss on ignition 2.98%.

[0078] The ceramic brick preparation method in this embodiment includes: Step B1, Lithium Slag Pretreatment: The sulfur content of the undesulfurized lithium slag is 12.88%. The fineness of the lithium slag is controlled to D50 of 20-50µm; the ratio of material to water in the lithium slag slurry is 1:2. Desulfurization is carried out using a flotation process with a hydroxamic acid oxidant. The process involves three scavenging stages: First, the amount of hydroxamic acid oxidant added is 0.03% of the weight of the lithium slag, stirred for 5 minutes, and foam is skimmed off. Second, the amount of hydroxamic acid oxidant added is 0.01% of the weight of the lithium slag, stirred for 5 minutes, and foam is skimmed off. Third, the amount of hydroxamic acid oxidant added is 0.005% of the weight of the lithium slag, stirred for 5 minutes, and foam is skimmed off. The dehydrated lithium slag is dried to obtain the treated lithium slag with a sulfur content of 2.65%, which is the desulfurized lithium slag, used for billet preparation.

[0079] Step B2, Sludge Pretreatment: After dewatering, the sludge is calcined at 900℃ to remove the abundant and complex organic matter, modify its morphology, fix key components, and activate its chemical activity, creating favorable conditions for low-temperature sintering. The calcined sludge is then crushed and used for billet preparation.

[0080] Step B3: The raw materials are aged and homogenized. Hard raw materials need to be crushed first to improve the efficiency and accuracy of wet ball milling. The coarse crushing fineness D50 of the raw materials is controlled at 20µm~50µm.

[0081] Step B4: Ingredient batching. Based on the moisture content of each raw material and the percentage of each raw material in the formula design, a belt feeder is used to accurately convey the batched raw materials to the ball mill.

[0082] Step B5: The raw materials are wet ball milled to obtain a formula slurry that meets the fineness requirements. The slurry is then sieved, iron removed, and aged. The fineness of the wet ball milling of the slurry is controlled to be 1.8% to 2.2% residue on a 250-mesh sieve.

[0083] Step B6: After the powder is prepared by spray drying, it is dry pressed to obtain a ceramic green body. The moisture content of the powder is controlled at 6.8%~7.2% and the dry body strength is 1.65MPa.

[0084] Step B7: After the green body with low-temperature glaze is dried, it is fired in a roller kiln at a temperature of 730℃ for 48 minutes to produce a semi-finished product. The semi-finished product after leaving the kiln is ground, air-dried, inspected, sorted by color, graded, and stored. The finished product has a water absorption rate of 1.08% and a modulus of rupture of 45MPa.

[0085] In this embodiment, the raw materials for the low-temperature glaze, by weight, include: 8 parts kaolin, 10 parts potassium feldspar, 3 parts calcined talc, 2.4 parts zirconium silicate, 76 parts high boron frit, 0.5 parts sodium tripolyphosphate, and 0.1 parts CMC.

[0086] The high-boron frit in the low-temperature glaze is the same as the high-boron frit used in the body formulation.

[0087] The chemical composition of the low-temperature glaze, by weight percentage, includes: SiO2 49.7%, Al2O3 7.3%, Na2O 7.15%, K2O 2.25%, CaO 1.55%, MgO 0.75%, Fe2O3 0.23%, B2O3 17.82%, ZnO 3.3%, BaO 7.45%, Loss on ignition 2.5%.

[0088] In this embodiment, the specific gravity of the low-temperature glaze is controlled at 1.55 to 1.60, the glaze amount (300×300mm plate) is 36g, and the fineness of the low-temperature glaze is controlled at 0.3% (residue on a 325-mesh sieve).

[0089] Example 3: like Figure 2 As shown, this application involves selecting and homogenizing the various raw materials in the ceramic body, followed by batching, wet ball milling, and then slurry homogenization and testing. After aging, sieving, iron removal, and spray granulation, powder is obtained. The powder is then aged, sieved, and pressed into shape to obtain a ceramic green body. The ceramic green body is then trimmed, cleaned, and dried.

[0090] To obtain the prepared low-temperature glaze, the specific steps are to wet ball mill the glaze water after mixing, and then test, sieve, remove iron, and age the glaze slurry to obtain the low-temperature glaze.

[0091] After glazing and inkjet printing decoration on the ceramic blanks, they are fired in the kiln. The semi-finished products after leaving the kiln are ground, air-dried, inspected, sorted by color and graded, and the finished products are put into storage.

[0092] This invention provides ceramic blanks, ceramic bodies, ceramic bricks, and preparation methods based on desulfurized lithium slag and calcined sludge. The ceramic blanks, by dry weight percentage, comprise: 5-10% bentonite, 1-3% modified starch, 20-35% calcined sludge, 20-35% desulfurized lithium slag, 25-35% high-boron frit, and 0.3-1.0% desizing agent. By incorporating desulfurized lithium slag and calcined sludge, this application enables more rational application of lithium slag and sludge, avoiding excessive accumulation. Furthermore, it solves the problems of high sulfate content in lithium slag raw materials affecting ceramic product quality and the impact of lithium slag raw materials on slurry fluidity when incorporated into the blank, as well as the impact of the high organic content of sludge raw materials on ceramic product quality. The synergistic effect of lithium slag, sludge, and high-boron frit, utilizing ultra-low temperature conditions to form a reinforcement mode with acicular anorthite as the main crystalline phase, changes the traditional blank system's reinforcement structure based on acicular mullite as the main crystalline phase.

[0093] It should be understood that the application of the present invention is not limited to the examples above. Those skilled in the art can make improvements or modifications based on the above description, and all such improvements and modifications should fall within the protection scope of the appended claims.

Claims

1. A ceramic blank based on desulfurized lithium slag and calcined sludge, characterized in that, The ceramic blank, by dry weight percentage, comprises: 5-10% bentonite, 1-3% modified starch, 20-35% calcined sludge, 20-35% desulfurized lithium slag, 25-35% high boron frit, and 0.3-1.0% degumming agent.

2. The ceramic blank based on desulfurized lithium slag and calcined sludge according to claim 1, characterized in that, The chemical composition of the ceramic blank, by weight percentage, includes: SiO2 40-50%, Al2O3 15-20%, K2O 1.8-2.5%, Na2O 3.5-5.5%, CaO 3.5-5.5%, MgO 0.3-1.0%, Fe2O3 3.5-7.5%, BaO 2.65-3.85%, B2O3 6.3-9.5%, ZnO 0.5-1.5%, P2O5 3.5-5.5%, Loss on ignition 4.5-5.5%.

3. The ceramic blank based on desulfurized lithium slag and calcined sludge according to claim 1, characterized in that, The chemical composition of the high-boron melt, by weight percentage, includes: SiO2 40-50%, Al2O3 1-5%, CaO 1-2%, MgO 0.1-0.5%, K2O 0.5-1.5%, Na2O 5-10%, B2O3 18-28%, ZnO 1-5%, BaO 5-12%, Loss on ignition 0.5-2.5%.

4. The ceramic blank based on desulfurized lithium slag and calcined sludge according to claim 1, characterized in that, The desulfurized lithium slag is obtained by reducing the sulfur content in the lithium slag raw material to 1.8-3.0% through a flotation desulfurization process. The calcined sludge is obtained by calcining sludge raw materials at a temperature of 900~950℃.

5. A ceramic body, characterized in that, The ceramic blank is prepared using ceramic blanks based on desulfurized lithium slag and calcined sludge as described in any one of claims 1 to 4.

6. A method for preparing a ceramic green body, characterized in that, include: The following ingredients are mixed by dry weight percentage: 5-10% bentonite, 1-3% modified starch, 20-35% calcined sludge, 20-35% desulfurized lithium slag, 25-35% high boron frit, and 0.3-1.0% degumming agent to obtain the mixed raw materials. The mixed raw materials are ball-milled to obtain a slurry, and the slurry is spray-dried to obtain a powder. The powder is dry-pressed to form a ceramic blank.

7. The method for preparing a ceramic green body according to claim 6, characterized in that, The moisture content of the powder is controlled at 6.8-7.2%, and the dry strength of the ceramic body obtained after drying is 1.2MPa-1.8MPa.

8. A method for preparing ceramic bricks, characterized in that, include: The ceramic green body prepared by the ceramic green body preparation method as described in claim 5 and / or as described in any one of claims 6 to 7 is dried to obtain a dry green body. A low-temperature glaze is applied to the surface of the dry blank, and surface decoration is performed to obtain a glazed blank; After drying, the glazed blank is fired in a kiln at a temperature of 700℃~750℃ for 35~50 minutes to obtain ceramic bricks. The ceramic brick has a water absorption rate of less than 3.0% and a modulus of rupture of greater than 40 MPa.

9. The method for preparing ceramic bricks according to claim 8, characterized in that, The raw materials for the low-temperature glaze, by weight, include: Kaolin 5-10 parts, potassium feldspar 10-15 parts, calcined talc 0-5 parts, zirconium silicate 0-5 parts, high boron frit 75-85 parts, sodium tripolyphosphate 0.3-0.5 parts, carboxymethyl cellulose 0.1-0.2 parts; The chemical composition of the low-temperature glaze, by weight percentage, includes: The composition is as follows: SiO2 45-55%, Al2O3 5-10%, Na2O 5-8%, K2O 1.5-2.5%, CaO 1-3%, MgO 0.5-2.5%, Fe2O3 0.15-0.3%, B2O3 15-25%, ZnO 1-4.5%, BaO 4.5-10%, and loss on ignition 1.5-3.5%.

10. A ceramic tile, characterized in that, The ceramic brick is prepared by the ceramic brick preparation method according to any one of claims 8 to 9.

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