A method for preparing highly acid-resistant willemite crystalline glaze architectural ceramics by using local phase separation

Abstract

The present invention belongs to the technical field of surface decoration of building ceramics, and specifically relates to a method for preparing highly acid-resistant willemite crystalline glaze building ceramics by using local phase separation. The method comprises the following steps: applying a base glaze on the surface of a ceramic tile blank; inkjet printing a glue pattern on the surface of the tile blank after applying the base glaze; applying seeding agent particles on the surface of the tile blank after the glue pattern is inkjet printed, and removing excess seeding agent particles that are not bonded after the glue is cured; drying, firing, and polishing the tile blank after applying the crystalline base glaze to obtain the highly acid-resistant willemite crystalline glaze building ceramics. The present invention optimizes the formula composition of willemite crystalline glaze and seeding agent, and uses seeding agent particles to regulate the local phase structure of the amorphous phase on the surface of the willemite crystalline phase, thereby improving the chemical stability of willemite crystals, and then greatly improving the acid resistance of willemite crystalline glaze building ceramics.

Description

Technical Field

[0001] The invention belongs to the technical field of surface decoration of building ceramics, and in particular relates to a method for preparing highly acid-resistant willemite crystalline glaze building ceramics by utilizing local phase separation. Background Art

[0002] Crystalline glaze is an artistic glaze with artificially controlled crystallization. Through controlled nucleation and crystallization growth, visible crystal flowers are formed in the glaze layer. The crystals are diverse in shape, size, colorful, and natural, which can greatly enhance the artistic beauty and aesthetic value of architectural ceramic products. At present, a variety of crystalline glaze composition systems have been developed at home and abroad, among which the ZnO-SiO2 system is the most important and widely used one. This system is easy to precipitate large-sized willemite crystal phases. Willemite crystal glaze has low high-temperature viscosity and high fluidity, so the crystal phase grows fast and has beautiful crystal shape. It can develop into round, fan-shaped, fiber / needle-shaped, and clustered crystal flowers, and is easily colored by metal oxides and has rich colors. It has a high artistic effect and is deeply loved by consumers.

[0003] However, the preparation of traditional willemite crystalline glaze architectural ceramics usually requires a two-step sintering method (Tyman crystallization theory), that is, after high-temperature firing, the temperature is lowered to the crystallization temperature for long-term insulation; and the firing temperature is as high as 1250~1320℃, and the insulation time is also as long as several hours. For example: Patent CN113754283B prepares zinc silicate crystalline glaze, which needs to be kept at a firing temperature of 1250℃ for 30 minutes, and then cooled to a crystallization temperature of 1100℃ and kept warm for 45~60 minutes; Patent CN 109987843 B zinc silicate positioning crystallization glaze requires a firing temperature of 1250~1270℃, and a heat preservation of 100~150 minutes at the crystallization temperature (1120~1160℃); Patent CN 114956560 B prepares new silicate crystalline glaze, which needs to be fired at 1200~1260℃ and 1100~1150℃ respectively. ℃, 1000~1050℃ for 8~10 min, 150~200 min, 220~260 min respectively. This results in high energy consumption, long production cycle and great difficulty in thermal control in the preparation of willemite crystalline glaze, making it difficult to be widely promoted and applied in the field of building ceramics. The building ceramics industry is facing a new trend of reducing consumption and increasing efficiency. It is urgent to develop low-temperature fast-firing technology for willemite crystalline glaze to meet the needs of low-energy consumption and high-efficiency manufacturing of crystalline glaze building ceramic products.

[0004] In addition, due to the poor acid resistance of the zinc silicate crystalline phase (Zn2SiO4 + 4HCl = 2ZnCl2 + H2SiO3 +H2O), the acid resistance of the prepared willemite crystalline glaze architectural ceramic products is also poor, and the glossiness and pollution resistance of the architectural ceramic glaze are significantly reduced after acid etching, which will greatly reduce the service life and user satisfaction of willemite crystalline glaze architectural ceramics. It is precisely because of the poor acid resistance of willemite crystalline glaze architectural ceramics that its commercial promotion and application are greatly limited. Therefore, improving the acid resistance of willemite crystalline glaze architectural ceramic products is a key technical problem that needs to be solved urgently. Summary of the invention

[0005] In view of this, the present invention optimizes the design of the formula composition of willemite crystalline glaze and seeding agent, which can not only realize the preparation of willemite crystalline glaze architectural ceramic products with complete flower structure and large crystal flower diameter under the low-temperature fast firing process conditions of a roller kiln; but also utilizes seeding agent particles to regulate the local phase structure of the amorphous phase on the surface of the willemite crystalline phase (i.e., the crystal flower position), which can improve the chemical stability of the willemite crystal flower, and then greatly improve the acid resistance of the willemite crystalline glaze architectural ceramics.

[0006] The method for preparing highly acid-resistant willemite crystalline glaze architectural ceramics by using local phase separation of the present invention comprises the following steps:

[0007] Applying base glaze to the surface of ceramic tile green;

[0008] inkjet printing a glue pattern on the surface of the brick after applying the base glaze;

[0009] Applying seeding agent particles on the surface of the brick after the glue pattern is inkjet printed, and removing excess seeding agent particles that are not bonded after the glue is cured; the seeding agent particles include a basic seeding agent and added Sb2O3, wherein the chemical composition of the basic seeding agent includes: in terms of mass percentage, SiO2 30-45%; Al2O3 10-15%; TiO2 10-15%; CaO 5-10%; K2O 1-4%; Na2O 2-4%; B2O3 2-5%; ZnO 25-40%; the mass percentage of Sb2O3 in the basic seeding agent is 0.3-0.5%;

[0010] Applying a crystallized base glaze on the surface of the brick after applying the seeding agent particles; the chemical composition of the crystallized base glaze includes: in terms of mass percentage, SiO2 18-37%; Al2O3 5-10%; Fe2O3 0.04-0.1%; TiO2 5-10%; CaO 6-12%; MgO 0.8-2.0%; K2O 2.5-5%; Na2O 2-4%; B2O3 0.5-2.0%; ZnO 14-35%; BaO 4-8%; ignition loss 0.7-1.7%;

[0011] The brick blank after being applied with the crystallized base glaze is dried, fired and polished to obtain the highly acid-resistant willemite crystallized glaze architectural ceramics.

[0012] Preferably, the seeding agent particles have a particle size of 30-60 mesh.

[0013] Preferably, the mineral composition of the basic seeding agent includes, by mass, 30 to 45 parts of quartz, 10 to 15 parts of corundum, 10 to 15 parts of TiO2, 9 to 18 parts of CaCO3, 1 to 6 parts of K2CO3, 3 to 10 parts of Na2CO3, 4 to 11 parts of zinc borate, and 23 to 40 parts of ZnO.

[0014] Preferably, the method for preparing the seeding agent particles comprises: uniformly mixing the mineral composition of the basic seeding agent with Sb2O3, heat treating at 1150-1250°C for 10-120 min, cooling to room temperature with the furnace, and crushing and screening to obtain the seeding agent particles.

[0015] Preferably, the grayscale of the glue pattern is 40-60%.

[0016] Preferably, the mineral composition of the crystalline base glaze includes, by mass, 56-79 parts of low-temperature frit, 5-10 parts of kaolin, 8-20 parts of ZnO, 5-10 parts of TiO2, and 1-4 parts of zinc borate; wherein the chemical composition of the low-temperature frit includes, by mass percentage, SiO2 35-45%; Al2O3 5-10%; CaO 10-20%; MgO 1-5%; K2O 5-8%; Na2O 3-8%; BaO 8-13%; and ZnO 10-20%.

[0017] Preferably, the crystalline base glaze is applied by pouring or spraying; the specific gravity of the crystalline base glaze is 1.60-1.80 g / cm 3 , glaze application amount is 800~1200 g / m 2 .

[0018] Preferably, the glue pattern is a one-dimensional line or a two-dimensional area pattern composed of isolated dots arranged in an array.

[0019] Preferably, the glaze surface of the highly acid-resistant willemite crystalline glaze architectural ceramics contains willemite crystal flowers composed of nano-microcrystalline willemite fibers and amorphous phases interlaced.

[0020] Preferably, the amorphous phase has a spherical droplet dispersed phase structure, including a ZnO-poor SiO2-Al2O3-rich base phase and a ZnO-rich SiO2-Al2O3-poor phase dispersed in the ZnO-poor SiO2-Al2O3-rich base phase in the form of isolated droplets.

[0021] Preferably, the chemical composition of the base glaze includes, by mass percentage, SiO2 49~60%; Al2O3 25~30%; Fe2O3 0.2~0.5%; TiO2 0.1~0.2%; CaO 0.3~0.8%; MgO 0.1~0.5%; K2O 2~6%; Na2O 2~3.5%; ZrO2 4~8%; and loss on ignition 2~5%.

[0022] Preferably, the base glaze is applied by spraying or pouring; the specific gravity of the base glaze is 1.40-1.45 g / cm 3 , glaze application amount is 500~650 g / m 2 .

[0023] Preferably, the sintering temperature is 1140-1160° C., and the sintering time is 50-70 min.

[0024] Beneficial Effects

[0025] 1. The present invention abandons the use of feldspar mineral raw materials (raw material system) as the flux of the glaze in the crystal-based glaze raw materials, and instead uses a CaO-ZnO-BaO system low-temperature frit (clinker system) to reduce the firing temperature of the willemite crystalline glaze; on the one hand, the use of the clinker system can promote the rapid formation and growth of zinc silicate crystals, and can produce willemite crystalline glaze architectural ceramic products with complete flower structure and large crystal diameter under the condition of low-temperature fast firing process in a roller kiln; on the other hand, the use of the clinker system can reduce glaze surface defects (such as glaze bubbles, pinholes, etc.) formed during the firing process, increase the production stability of willemite crystalline glaze architectural ceramics, and improve the yield rate of willemite crystalline glaze architectural ceramic products.

[0026] 2. The present invention utilizes a seeding agent to not only realize the controllable positioning of willemite crystals, but also utilizes the high-temperature melting diffusion of the seeding agent and the chemical components of the crystalline base glaze to form a SiO2-Al2O3-TiO2-B2O3-enriched glass phase in a local area, promotes the formation of a spherical droplet dispersed phase structure, and makes the unstable ZnO-rich SiO2-Al2O3-poor phase dispersed in the ZnO-poor SiO2-Al2O3-rich phase in the form of isolated droplets, thereby protecting the ZnO-rich SiO2-Al2O3-poor phase and the nano-microcrystalline willemite fiber from being corroded by acid media, thereby improving the acid resistance of the willemite crystalline glaze. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 is an exemplary process flow chart of the preparation of highly acid-resistant willemite crystalline glaze architectural ceramics of the present invention;

[0028] Figure 2 is the XRD pattern of the seeding agent particles of the present invention;

[0029] Figure 3 This is a partial optical photograph of the highly acid-resistant willemite crystalline glaze architectural ceramics prepared in Example 1;

[0030] Figure 4 is a microscopic photograph of willemite crystal flowers of the highly acid-resistant willemite crystalline glaze architectural ceramics prepared in Example 1;

[0031] Figure 5 This is the XRD spectrum of the glaze layer of the highly acid-resistant willemite crystalline glaze architectural ceramics prepared in Example 1;

[0032] Figure 6 is a SEM image of the willemite crystalline glaze of the highly acid-resistant willemite crystalline glaze architectural ceramics prepared in Example 1;

[0033] Figure 7 The microstructure of the amorphous phase on the surface of willemite crystals of the highly acid-resistant willemite crystalline glaze architectural ceramics prepared in Example 1;

[0034] Figure 8 This is a SEM image of the amorphous phase at the crystal flower position of the willemite crystalline glaze architectural ceramics prepared in Comparative Example 1. DETAILED DESCRIPTION

[0035] The present invention is further described by the following embodiments. It should be understood that the following embodiments are only used to illustrate the present invention, but not to limit the present invention.

[0036] The acid resistance optimization mechanism / principle mainly involved in the present invention is: the crystal petals in the willemite crystalline glaze are composed of a large number of nano-microcrystalline willemite fibers isolated by an amorphous phase (high-temperature melt), and the nano-microcrystalline willemite fibers are spatially staggered in three-dimensional space; the acid resistance of the zinc silicate crystalline phase itself is poor (Zn2SiO4 + 4HCl = 2ZnCl2 +H2SiO3 + H2O), so the key to improving the acid resistance of the willemite crystalline glaze is to improve the acid resistance of the amorphous phase near the nano-microcrystalline willemite fibers. However, since willemite is a ZnO-SiO2-rich phase, containing 72.97 wt% ZnO and 27.03 wt% SiO2, the precipitation of willemite crystalline phase will reduce the ZnO and SiO2 contents in the surrounding amorphous phase, easily forming a worm-like network connected phase structure. The continuous distribution of ZnO-rich and SiO2-poor phases-Al2O3 and their poor chemical stability can easily lead to reduced acid resistance of the amorphous phase; further, the protective effect of the amorphous phase on nano-microcrystalline willemite fibers is weakened, thereby greatly reducing the acid resistance of willemite crystalline glaze architectural ceramics. The present invention optimizes the chemical composition of seeding agent particles and crystallization base glaze, utilizes the high-temperature melting diffusion of seeding agent particles and crystallization base glaze chemical components to form SiO2-Al2O3-TiO2-B2O3-enriched glass phase in local area, promotes the formation of spherical droplet dispersed phase structure, makes unstable ZnO-rich SiO2-Al2O3-poor phase dispersed in ZnO-poor SiO2-Al2O3-rich phase in the form of isolated droplets, can protect ZnO-rich SiO2-Al2O3-poor phase and nano-microcrystalline willemite fiber from being corroded by acid medium, thereby improving the acid resistance of willemite crystallization glaze.

[0037] The following combination Figure 1 The method for preparing highly acid-resistant willemite crystalline glaze architectural ceramics by utilizing local phase separation according to the present invention is exemplified.

[0038] Prepare ceramic tile blanks. The present invention has no special requirements for ceramic tile blanks, which can be ordinary brick blanks. Ceramic tile blanks can be prepared by dry pressing ceramic blank powder. The ceramic blank powder can be made of conventional building ceramic formula. As an example, the chemical composition of the ceramic tile blank includes: in mass percentage, SiO2 67.8%; Al2O3 20.0%; Fe2O3 1.1%; TiO2 0.3%; CaO 0.3%; MgO 0.9%; K2O 2.9%; Na2O 1.9%; loss on ignition 4.8%.

[0039] The green bricks are dried. The drying temperature and drying time are conventional settings in the art. The moisture content of the green ceramic bricks after drying can be controlled to be 0.3-0.5wt%.

[0040] Apply base glaze on the surface of the dried ceramic tile blank. Conventional base glaze for building ceramics can be used. For example, a base glaze of a high aluminum system is used. As an example, the chemical composition of the base glaze includes: in mass percentage, SiO2 49~60%; Al2O3 25~30%; Fe2O3 0.2~0.5%; TiO2 0.1~0.2%; CaO 0.3~0.8%; MgO 0.1~0.5%; K2O 2~6%; Na2O 2~3.5%; ZrO2 4~8%; loss on burning 2~5%. The main function of the base glaze is to cover the blank, improve the whiteness of the brick blank, and provide an exhaust channel during the high-temperature firing process of the blank to avoid the occurrence of glaze defects; in addition, the thermal expansion coefficient of the base glaze is lower than that of the ceramic tile blank, which is conducive to adjusting the brick shape and ensuring the smooth surface of the willemite crystalline glaze building ceramics.

[0041] There is no special regulation on the application method of the base glaze, which can be pouring glaze or spraying glaze. In some embodiments, the specific gravity of the base glaze is 1.40-1.45 g / cm 3 , glaze application amount is 500~650g / m 2 .

[0042] The bricks after applying the base glaze are dried at a conventional temperature and time in the art.

[0043] The dried glazed ceramic tile blank is subjected to inkjet printing of patterned glue. The glue pattern is prepared on the surface of the dried glazed ceramic tile blank by using an inkjet printer. The present invention has no limitation on the material of the glue used, which can be a glue known in the art or a commercial glue product.

[0044] The glue printing position is determined according to the design pattern. Based on the vectorization processing of the design file, the glue is sprayed at a fixed point by an inkjet printer to achieve patterned application of glue.

[0045] Preferably, the printing grayscale of the glue pattern is 40-60%. If the printing grayscale is too low, it will be difficult for the seeding agent particles applied subsequently to be firmly bonded to the surface of the brick, and some of the seeding agent particles will fall off, causing the printed pattern to be distorted; if the printing grayscale is too high, the seeding agent particles will be too bonded, and the seeding agent particles will be easily stacked, which will lead to the overlapping and aggregation of subsequent crystal flowers, reducing the decorative effect of the crystal flowers.

[0046] The glue pattern can be a one-dimensional line or two-dimensional area pattern composed of isolated dots arranged in an array. The purpose of this arrangement can also be to avoid the stacking of seeding agent particles. The positioning crystal flowers formed by the subsequent seeding agent and the crystallization base glaze form a one-dimensional line or a two-dimensional area pattern.

[0047] The shape of the dots can be round or square. The diameter or side length of the dots is preferably 0.2~0.6 mm. If the size of the dots is too small, it is difficult to reliably bond the seeding agent particles, which may cause the seeding agent particles to fall off during the subsequent brick transportation or glaze spraying process; if the size of the dots is too large, it may cause multiple seeding agent particles to accumulate at the same position, reducing the three-dimensional dispersion effect of the crystal flowers. The dot spacing is preferably 1.5~3.5 mm, which is also to obtain a glaze decoration effect with a certain number, size and reasonable distribution of crystal flowers. If the dot spacing is too small, it is easy to cause overlapping and accumulation of crystal flowers; if the dot spacing is too large, the crystal flowers are sparsely distributed, and it is difficult to form a continuous crystal flower pattern.

[0048] Apply seeding agent particles on the surface of the brick after applying the glue pattern. The glue can achieve a firm bond between the seeding agent particles and can also dry and solidify quickly. After the glue solidifies, use an exhaust fan to remove excess unbonded seeding agent particles.

[0049] In some embodiments, the seeding agent particles include a basic seeding agent and added Sb2O3. The chemical composition of the basic seeding agent includes, by mass percentage, SiO2 30-45%; Al2O3 10-15%; TiO2 10-15%; CaO 5-10%; K2O 1-4%; Na2O 2-4%; B2O3 2-5%; and ZnO 25-40%.

[0050] The mass percentage of Sb2O3 in the basic seeding agent can be 0.3-0.5%. The introduction of Sb2O3 (clarifier) ​​can promote the exhaust of the seeding agent high-temperature melt, avoid introducing too many pores in the seeding agent particles, and improve the density of the seeding agent particles, thereby reducing the number of defects such as glaze bubbles and pinholes near the crystal flower position of the crystalline glaze, which is beneficial to improving the surface quality of crystalline glaze architectural ceramics.

[0051] In some embodiments, the ZnO content of the seeding agent particles is higher than that of the subsequently applied crystalline base glaze, so that a ZnO-rich region can be formed at the seeding agent position, which is beneficial to promote the precipitation of willemite crystalline phase, and then the seeding agent particles can be used to achieve controllable positioning of willemite crystals.

[0052] In some embodiments, the SiO2, Al2O3, TiO2, and B2O3 content of the seeding agent particles is higher than or equal to that of the subsequently applied crystalline base glaze. On the one hand, SiO2 and Al2O3, as network formers, can effectively improve the acid resistance and chemical stability of the glass phase; on the other hand, TiO2 and B2O3 can improve the phase separation ability of the glass phase and promote the formation of a spherical droplet dispersed phase separation structure, thereby avoiding the formation of a network interconnected phase separation structure, and effectively improving the acid resistance of the glass phase in the crystal flower.

[0053] The seeding agent particles prepared by high temperature heat treatment contain a large amount of willemite crystalline phase (such as Figure 2 As shown). Due to the large amount of TiO2 and B2O3 in the seeding agent, the seeding agent has excellent phase separation ability. The phase separation interface can provide a nucleation position for the precipitation of willemite crystalline phase, which is beneficial to improve the crystallization ability of the seeding agent high-temperature melt, and then the willemite crystalline phase can be effectively precipitated during the cooling process after heat treatment. During the firing process of ceramic tiles, the seeding agent and the crystalline base glaze melt and level, and the willemite crystalline phase in the seeding agent will gradually melt into the high-temperature glass phase. The firing temperature control can make part of the willemite crystalline phase remain; based on the lattice matching principle, the residual willemite crystalline phase can be used as the crystal nucleus of the crystalline glaze, effectively promoting the nucleation and growth of willemite.

[0054] The seeding agent particles have a particle size of 30-60 mesh. If the seeding agent particles are too large, it is difficult to effectively melt flat during the firing process of architectural ceramics, which may lead to a decrease in the flatness of the glaze surface; while if the seeding agent particles are too small, it is difficult to effectively form a SiO2-Al2O3-TiO2-B2O3-enriched glass phase at the crystal flower position.

[0055] The present invention does not limit the raw material composition of the basic seeding agent. In some embodiments, quartz, corundum, TiO2, CaCO3, K2CO3, Na2CO3, zinc borate (2ZnO·3B2O3·3.5H2O), and ZnO are used as raw materials for the basic seeding agent. For example, the mineral composition of the basic seeding agent includes: by mass, 30 to 45 parts of quartz, 10 to 15 parts of corundum, 10 to 15 parts of TiO2, 9 to 18 parts of CaCO3, 1 to 6 parts of K2CO3, 3 to 10 parts of Na2CO3, 4 to 11 parts of zinc borate, and 23 to 40 parts of ZnO. In addition, Sb2O3 is additionally added to the basic seeding agent. For example, 0.3 to 0.5 parts by mass of Sb2O3 are added to 100 parts by mass of the basic seeding agent. The above raw materials are mixed evenly and then heat treated at high temperature. The heat treatment temperature can be 1150~1250℃, and the holding time can be 10~120min. After the holding is completed, it is cooled with the furnace. Then, it is crushed and screened to obtain the seeding agent particles.

[0056] The seeding agent can be prepared in the following manner: weigh 30-45 parts by mass of quartz, 10-15 parts by mass of corundum, 10-15 parts by mass of TiO2, 9-18 parts by mass of CaCO3, 1.5-6 parts by mass of K2CO3, 3.4-6.8 parts by mass of Na2CO3, 4.1-10.4 parts by mass of zinc borate, 23.5-36.1 parts by mass of ZnO and 0.3-0.5 parts by mass of Sb2O3 (clarifier), mix and dry the above raw materials by ball milling, place them in an alumina crucible for high-temperature heat treatment, and cool them with the furnace after insulation is completed; then crush and screen them to obtain the seeding agent particles.

[0057] The above is only an example of the preparation of seeding agent particles. As long as the chemical composition of the basic seeding agent (after high-temperature heat treatment) meets the requirements (the chemical composition of the basic seeding agent includes: in terms of mass percentage, SiO2 30~45%; Al2O3 10~15%; TiO2 10~15%; CaO 5~10%; K2O 1~4%; Na2O 2~4%; B2O3 2~5%; ZnO 25~40%), even if other raw materials (such as glass powder, frit, feldspar, borax, sphalerite, etc.) are used, they are also within the scope of protection of the present invention.

[0058] A crystal-based glaze is applied to the surface of the brick with the seeding agent particles and dried. The chemical composition of the crystal-based glaze includes: by mass percentage, SiO2 18-37%; Al2O3 5-10%; Fe2O3 0.04-0.1%; TiO2 5-10%; CaO 6-12%; MgO 0.8-2.0%; K2O 2.5-5%; Na2O 2-4%; B2O3 0.5-2.0%; ZnO 14-35%; BaO 4-8%; loss on ignition 0.7-1.7%. The crystal-based glaze provides a growth environment for the willemite crystal phase, is a high zinc system, and has a lower initial melting temperature and a lower high temperature viscosity to promote the rapid growth of willemite crystals.

[0059] As an example, the chemical composition of the crystalline base glaze includes, by mass percentage, SiO2 24~37%; Al2O3 6~10%; Fe2O3 0.04~0.1%; TiO2 5~10%; CaO 8~12%; MgO 1.1~1.6%; K2O 3.5~5%; Na2O 2.8~4%; B2O3 0.5~2.0%; ZnO 16~33%; BaO 5~8%; and loss on ignition 0.7~1.7%. As another example, the chemical composition of the crystalline base glaze includes, by mass percentage, SiO2 18~33%; Al2O3 5~9%; Fe2O3 0.04~0.1%; TiO2 5~10%; CaO 6~11%; MgO 0.8~1.4%; K2O 2.5~4.5%; Na2O 2~3.5%; B2O3 0.5~2.0%; ZnO 14~ 31%; BaO 4~7%; and loss on ignition 0.7~1.7%.

[0060] The mineral composition of the crystalline base glaze includes: by mass, 56-79 parts of low-temperature frit, 5-10 parts of kaolin, 8-20 parts of ZnO, 5-10 parts of TiO2, and 1-4 parts of zinc borate. Wherein, the low-temperature frit is a CaO-ZnO-BaO system low-temperature frit. In some embodiments, the chemical composition of the low-temperature frit includes: by mass percentage, SiO2 35-45%; Al2O3 5-10%; CaO 10-20%; MgO 1-5%; K2O 5-8%; Na2O 3-8%; BaO 8-13%; ZnO 10-20%. For example, the chemical composition of the low-temperature frit includes: by mass percentage, SiO2 40%; Al2O 3 8%; CaO 15%; MgO 2%; K2O 6%; Na2O 5%; BaO 10%; ZnO 14%.

[0061] The crystalline base glaze is a clinker system, which can effectively avoid the formation of glaze defects caused by the burning loss of the raw material system, increase the production stability of willemite crystalline glaze architectural ceramics, and improve the yield rate of willemite crystalline glaze architectural ceramic products; in addition, the raw material system will absorb a large amount of heat during the burning loss process, which is not conducive to the low-temperature fast firing manufacturing of the crystalline glaze, while the clinker system can effectively solve this problem.

[0062] Using a two-step firing process (first, heating to 1140~1160℃, keeping warm for 10~20min, then cooling to 820~1000℃, keeping warm for 30~120min), the crystalline base glaze itself can form willemite crystals. However, under the low-temperature fast firing process of the roller kiln, it is difficult for the crystalline base glaze itself (without adding a seeding agent) to form crystals.

[0063] The glaze slurry of the crystal-based glaze can be prepared in the following manner: the mineral composition of the crystal-based glaze includes: 56-79 parts by mass of low-temperature frit, 5-10 parts by mass of kaolin, 8-20 parts by mass of ZnO, 5-10 parts by mass of TiO2, and 1-4 parts by mass of zinc borate. In addition, 0.2-0.3 parts by mass of sodium tripolyphosphate and 0.1-0.2 parts by mass of sodium carboxymethyl cellulose are added to the mineral composition of the crystal-based glaze as dispersants to ensure the dispersion stability of the crystal-based glaze slurry. The above raw materials are placed in a ball mill for ball milling. After ball milling, the glaze slurry has a 325-mesh sieve residue of ≤0.5wt%.

[0064] There is no special requirement for the application method of the crystalline base glaze. The crystalline base glaze can be applied by pouring or spraying. In some embodiments, the specific gravity of the crystalline base glaze is 1.60-1.80 g / cm 3 , glaze application amount is 800~1200g / m 2If the amount of crystalline base glaze applied is too small, the willemite crystals will be difficult to grow; if the amount of glaze applied is too large, the crystalline glaze layer will be too thick, which will not be conducive to adjusting the brick shape on the one hand, and will easily cause the overall crystallization of the crystalline base glaze on the other hand, resulting in a poor sense of transparency.

[0065] The ceramic tile blank after the crystallization base glaze is applied is dried, fired and polished to obtain the highly acid-resistant willemite crystallization glaze architectural ceramics. The edge grinding process can be performed before polishing.

[0066] Firing is performed using a roller kiln. In some embodiments, the firing temperature is 1140-1160°C, and the firing time is 50-70min. The firing process parameters are matched with the formula composition of the seeding agent particles and the crystalline base glaze. If the firing temperature is too low or the firing time is too short, it is easy to cause the willemite crystal flower to be difficult to grow, and its diameter is less than 2mm, which reduces the decorative effect of the crystal flower. Moreover, if the firing temperature is too low or the firing time is too short, it will also cause the seeding agent particles to be difficult to effectively melt flat, reducing the glaze quality of the crystalline glaze architectural ceramics. If the firing temperature is too high or the firing time is too long, the high-temperature melting and diffusion of the seeding agent particles and the crystalline base glaze will be aggravated, and it will be difficult to effectively regulate the chemical composition of the glass phase at the crystal flower position, that is, it is impossible to effectively increase the SiO2, Al2O3, TiO2, and B2O3 content at the crystal flower position, so it is difficult to form an isolated spherical droplet dispersed phase structure, and it is difficult to effectively improve the acid resistance of the willemite crystalline glaze architectural ceramics.

[0067] The willemite crystal glaze architectural ceramics prepared by the present invention has lines or patterns formed by crystal flowers in the glaze surface. The crystal flower phase is willemite. For example, the diameter of a single crystal flower is ≥ 2 mm. And the glass phase in the crystal flower has a spherical droplet dispersed phase structure.

[0068] In summary, in order to improve the chemical stability and service life of willemite crystalline glaze architectural ceramic products, the present invention proposes a method for improving the acid resistance of willemite crystalline glaze architectural ceramics by using local phase separation, which has the following beneficial effects:

[0069] (1) The use of seeding agent particles is beneficial to the controllable positioning of crystal flowers in the crystalline glaze layer. On the other hand, the high-temperature melting local diffusion of seeding agent particles and crystalline base glaze improves the chemical composition of the amorphous phase near the nano-microcrystalline willemite fibers of the crystal flowers, optimizes the phase structure of the amorphous phase there, and promotes the formation of a spherical droplet dispersed phase structure, so that the unstable ZnO-rich SiO2-Al2O3-poor phase is dispersed in the ZnO-poor SiO2-Al2O3-rich phase in the form of isolated droplets, which can protect the ZnO-rich SiO2-Al2O3-poor phase and the nano-microcrystalline willemite fibers from being corroded by acid media, thereby improving the acid resistance of the willemite crystalline glaze.

[0070] The phase separation of the amorphous phase is the selective enrichment of chemical components due to the migration of internal particles during the cooling process of the high-temperature melt, thereby forming two phases with different chemical components. For the components of the crystalline glaze layer of the present invention, SiO2 and Al2O3, as network formers, are easy to attract bridging oxygen ions to their surroundings; while ZnO, as a network exosome, is easy to attract non-bridging oxygen ions and arrange them according to its own ionic structure; thus, the ZnO network exosome ions with a larger field strength and a larger content are difficult to form a stable amorphous phase by themselves, and are separated from the silicon oxygen and aluminum oxygen network structures, so that the amorphous phase is phase-separated. The present invention is based on the chemical composition design of the local position of the crystal flower realized by the seeding agent, and the phase separation ability of the amorphous phase near it is regulated, so that it is easy to form a phase separation structure of isolated and dispersed spherical droplets, including a ZnO-rich SiO2-Al2O3-poor phase and a ZnO-poor SiO2-Al2O3-rich phase. Since the increase of ZnO content will sharply reduce the network integrity and chemical stability of the amorphous phase, the acid resistance and chemical stability of the ZnO-rich and SiO2-Al2O3-poor phase are worse than those of the ZnO-poor and SiO2-Al2O3-rich phase; however, the present invention is based on the phase structure regulation, so that the unstable ZnO-rich and SiO2-poor phase is dispersed in the ZnO-poor and SiO2-Al2O3-rich phase in the form of isolated droplets, which can protect the ZnO-rich and SiO2-Al2O3-poor phase and the nano-microcrystalline willemite fiber from being corroded by the acid medium, thereby improving the acid resistance of the willemite crystalline glaze. The rich and poor in the phase are defined according to the relative amount of content.

[0071] (2) The present invention abandons the use of feldspar mineral raw materials (raw material system) as flux in the crystal-based glaze raw materials, and instead uses a CaO-ZnO-BaO system low-temperature melting block (clinker system) to reduce the firing temperature of the willemite crystalline glaze; on the one hand, the use of the clinker system can promote the rapid formation and growth of zinc silicate crystals, and can produce willemite crystalline glaze architectural ceramic products with complete flower structure and large crystal diameter under the low-temperature fast firing process conditions of a roller kiln; on the other hand, the use of the clinker system can reduce the glaze surface defects (such as glaze bubbles, pinholes, etc.) formed during the firing process, which can increase the production stability of willemite crystalline glaze architectural ceramics and improve the yield rate of willemite crystalline glaze architectural ceramics.

[0072] The following examples are further listed to illustrate the present invention in detail. It should also be understood that the following examples are only used to further illustrate the present invention and cannot be understood as limiting the scope of protection of the present invention. Some non-essential improvements and adjustments made by those skilled in the art based on the above content of the present invention belong to the scope of protection of the present invention. The specific process parameters and the like in the following examples are also only examples within a suitable range, that is, those skilled in the art can make a selection within a suitable range through the description herein, and are not limited to the specific values ​​​​exemplified below.

[0073] Example 1

[0074] A method for preparing highly acid-resistant willemite crystalline glaze architectural ceramics by using local phase separation, the specific preparation steps are as follows:

[0075] Step 1: Prepare ceramic tile blanks by dry pressing ceramic blank powder and perform drying.

[0076] Step 2. Apply a base glaze on the dried brick surface by spraying. The chemical composition of the base glaze includes: by mass percentage, SiO2 54.5%; Al2O3 29.1%; Fe2O3 0.4%; TiO2 0.1%; CaO 0.7%; MgO 0.2%; K2O 2.4%; Na2O 3.4%; ZrO2 5.8%; loss on ignition 3.4%. The specific gravity of the base glaze is controlled to be 1.40 g / cm 3 , glaze application amount is 500g / m 2 .

[0077] Step 3: According to the glue pattern design (the glue pattern is composed of isolated dots arranged in an array, the diameter of the dots is 0.2 mm, and the dot spacing is 3.5 mm), use an inkjet printer to prepare the glue pattern on the surface of the dried ceramic tile blank after the base glaze is applied. The grayscale of the glue printing is 40%.

[0078] Step 4: Prepare seeding agent particles. Weigh 30 parts by mass of quartz, 10 parts by mass of corundum, 10 parts by mass of TiO2, 9 parts by mass of CaCO3, 5.9 parts by mass of K2CO3, 3.4 parts by mass of Na2CO3, 10.4 parts by mass of zinc borate (2ZnO·3B2O3·3.5H2O), 30.1 parts by mass of ZnO and Sb2O3 respectively, and place them in a ball mill together with 218 parts by mass of corundum grinding balls and 65 parts by mass of water, and perform ball milling mixing (350r / min, ball milling for 1h); after drying, the seeding agent powder is obtained, and it is placed in an alumina crucible for high-temperature heat treatment (heat treatment temperature is 1150℃, insulation time is 120min, and it is cooled with the furnace after insulation). Subsequently, the high-temperature heat treated sample is crushed, and 30-40 mesh particles are screened out for use, that is, the seeding agent particles are obtained. The chemical composition of the basic seeding agent includes, by mass percentage, SiO2 30%, Al2O3 10%, TiO2 10%, CaO 5%, K2O 4%, Na2O 2%, B2O 35%, and ZnO 34%. The mass percentage of Sb2O3 in the basic seeding agent is 0.3%.

[0079] Step 5: Apply seeding agent particles on the surface of the brick after the glue pattern is applied. After the glue is cured, use an exhaust fan to remove excess unbonded seeding agent particles.

[0080] Step 6: Prepare crystalline base glaze. Weigh 70 parts by mass of low-temperature frit (CaO-ZnO-BaO is a low-temperature frit, whose chemical composition includes, by mass percentage, SiO2 40%; Al2O3 8%; CaO 15%; MgO 2%; K2O 6%; Na2O 5%; BaO10%; ZnO 14%), 6 parts by mass of kaolin, 15 parts by mass of ZnO, 8 parts by mass of TiO2, 1 part by mass of zinc borate, 0.2 parts by mass of sodium tripolyphosphate, and 0.2 parts by mass of sodium carboxymethyl cellulose, and place them in a ball mill for ball milling (the residue on the 325 mesh sieve of the glaze slurry after ball milling is ≤0.5wt%), and control the specific gravity of the glaze slurry to 1.80g / cm by the amount of water added. 3 The crystalline base glaze can be prepared for use. The chemical composition of the crystalline base glaze includes, by mass percentage, SiO2 30.95%; Al2O3 7.7%; Fe2O3 0.05%; TiO2 8%; CaO 10.5%; MgO 1.4%; K2O 4.4%; Na2O 3.5%; B2O3 0.5%; ZnO 25.2%; BaO 7%; and ignition loss 0.8%.

[0081] Step 7: Apply a crystallization base glaze on the surface of the brick with the seeding agent by pouring glaze. The amount of the crystallization base glaze applied is 800 g / m 2 . This is followed by a drying process.

[0082] Step 8: The dried bricks with the crystalline base glaze applied are fired in a roller kiln at a temperature of 1140°C and a firing time of 70 min.

[0083] Step 9: After the firing is completed, edge grinding and polishing are performed to obtain the highly acid-resistant siliceous zinc ore crystalline glaze architectural ceramics.

[0084] The partial photos of the prepared willemite crystalline glaze architectural ceramics were taken using an optical camera, such as Figure 3 As shown in the figure, the crystal flowers in the crystalline glaze layer are distributed in a certain number and size, and the crystal flowers are mainly distributed in isolation, with less repeated stacking. The crystal flower pattern structure is complete and has a strong three-dimensional sense, which has a good decorative effect.

[0085] Furthermore, the microscopic photographs of the crystal flowers were obtained using an optical microscope, such as Figure 4 As shown, the crystal flower has obvious flower shape characteristics and the crystal flower diameter is about 2.5 mm.

[0086] The XRD pattern of the crystalline glaze was measured by X-ray diffractometer, such as Figure 5 As shown in the figure, the main phase composition of the crystalline glaze architectural ceramic glaze layer is willemite (Zn2SiO4), indicating that Figure 3 , Figure 4The physical phase composition of the mesocrystalline flowers is willemite, that is, the mesocrystalline flowers in the obtained crystalline glaze are willemite crystal flowers.

[0087] According to GB / T 3810.13-2016 (Test methods for ceramic tiles Part 13: Determination of chemical corrosion resistance), the architectural ceramic glaze was immersed in 3 vol% and 18 vol% hydrochloric acid solutions, respectively, and the acid resistance of the prepared willemite crystalline glaze architectural ceramics was measured to be GLA and GHA level (no obvious corrosion visible to the naked eye at the crystal flower position). In addition, the microstructure of the prepared willemite crystalline glaze (corroded by 5 wt% HF solution for 60s) was measured by SEM, such as Figure 6 As shown in Figure 1, willemite crystals are composed of a large number of nanocrystalline fibers separated by amorphous phases (because the willemite crystalline phase has been acid-etched, Figure 6 The fibrous pores in the fiber are willemite microcrystalline fibers, with a diameter of about 100-450 nm. Nanocrystalline willemite fibers are interlaced with the amorphous phase to form willemite crystal flowers. Furthermore, the microstructure of the amorphous phase on the surface of the crystal flower was measured by SEM, such as Figure 7 As shown in the figure, the amorphous phase on the surface of willemite crystal flower presents a typical spherical droplet isolated dispersed phase structure, which makes the unstable ZnO-rich SiO2-Al2O3-poor phase dispersed in the ZnO-poor SiO2-Al2O3-rich phase in the form of isolated droplets, which can protect the ZnO-rich SiO2-Al2O3-poor phase and nano-microcrystalline willemite fibers from being corroded by acid medium, thereby improving the acid resistance of willemite crystalline glaze. In addition, the diameter of the spherical droplets in the amorphous phase is only 90~120 nm, which is much smaller than the wavelength of visible light (380~780 nm). Therefore, the isolated phase droplet structure does not reduce the visible light transmittance (i.e., light transmittance) of the crystalline glaze, and the crystalline base glaze is still transparent, as shown in Figure 1. Figure 3 shown.

[0088] Example 2

[0089] A method for preparing highly acid-resistant willemite crystalline glaze architectural ceramics by using local phase separation, the specific preparation steps are as follows:

[0090] Step 1: Prepare ceramic tile blanks by dry pressing ceramic blank powder and perform drying.

[0091] Step 2: Apply the base glaze on the dried brick surface by spraying. The chemical composition of the base glaze includes: by mass percentage, SiO2 49.7%; Al2O3 30.0%; Fe2O3 0.5%; TiO2 0.1%; CaO 0.8%; MgO 0.4%; K2O 6.0%; Na2O 2.5%; ZrO2 5.5%; loss on ignition 4.5%. The specific gravity of the base glaze is controlled to be 1.42 g / cm 3 , glaze application amount is 600 g / m2 .

[0092] Step 3: According to the glue pattern design (the glue pattern is composed of isolated dots arranged in an array, the diameter of the dots is 0.6 mm, and the dot spacing is 1.5 mm), use an inkjet printer to prepare the glue pattern on the surface of the dried glazed ceramic tile blank. The grayscale of the glue printing is 60%.

[0093] Step 4: Prepare seeding agent particles. Weigh 35 parts by mass of quartz, 15 parts by mass of corundum, 10 parts by mass of TiO2, 9 parts by mass of CaCO3, 5.9 parts by mass of K2CO3, 6.8 parts by mass of Na2CO3, 4.1 parts by mass of zinc borate (2ZnO·3B2O3·3.5H2O), 23.5 parts by mass of ZnO and Sb2O3 respectively, and place them in a ball mill together with 218 parts by mass of corundum grinding balls and 65 parts by mass of water, and perform ball milling mixing (350r / min, ball milling for 1h); after drying, the seeding agent powder is obtained, and it is placed in an alumina crucible for high-temperature heat treatment (heat treatment temperature is 1250℃, insulation time is 10min, and after insulation is completed, it is cooled with the furnace). Subsequently, the high-temperature heat-treated sample is crushed, and 40-60 mesh particles are sieved out for use, that is, the seeding agent particles are obtained. The chemical composition of the basic seeding agent includes, by mass percentage, SiO2 35%, Al2O3 15%, TiO2 10%, CaO 5%, K2O 4%, Na2O 4%, B2O3 2%, and ZnO 25%. The mass percentage of Sb2O3 in the basic seeding agent is 0.5%.

[0094] Step 5: Apply seeding agent particles on the surface of the brick after the glue pattern is applied. After the glue is cured, use an exhaust fan to remove excess unbonded seeding agent particles.

[0095] Step 6: Prepare crystalline base glaze. Weigh 56 parts by mass of low-temperature frit (CaO-ZnO-BaO is a low-temperature frit, whose chemical composition includes, by mass percentage, SiO2 40%; Al2O3 8%; CaO 15%; MgO 2%; K2O 6%; Na2O 5%; BaO10%; ZnO 14%), 10 parts by mass of kaolin, 20 parts by mass of ZnO, 10 parts by mass of TiO2, 4 parts by mass of zinc borate, 0.3 parts by mass of sodium tripolyphosphate, and 0.1 parts by mass of sodium carboxymethyl cellulose, and place them in a ball mill for ball milling (the residue on the 325 mesh sieve of the glaze slurry after ball milling is ≤0.5wt%), and control the specific gravity of the glaze slurry to 1.60g / cm by the amount of water added. 3The crystalline base glaze can be prepared for use. The chemical composition of the crystalline base glaze includes, by mass percentage, SiO2 27.62%; Al2O 38%; Fe2O 30.08%; TiO2 10%; CaO 8.4%; MgO 1.1%; K2O 3.7%; Na2O 2.8%; B2O 32%; ZnO 29.3%; BaO 5.6%; and loss on ignition 1.7%.

[0096] Step 7: Apply a crystallized base glaze on the surface of the brick with the seeding agent by pouring glaze. The amount of the crystallized base glaze applied is 1200 g / m 2 . This is followed by a drying process.

[0097] Step 8: The dried bricks with the crystalline base glaze applied are fired in a roller kiln at a temperature of 1160°C and a firing time of 50 min.

[0098] Step 9: After the firing is completed, edge grinding and polishing are performed to obtain the highly acid-resistant willemite crystalline glaze architectural ceramics.

[0099] The crystal flower has a distinct flower shape and a diameter of about 3.3 mm. According to GB / T 3810.13-2016 (Part 13 of Test Methods for Ceramic Tiles: Determination of Chemical Corrosion Resistance), the architectural ceramic glaze was immersed in 3 vol% and 18 vol% hydrochloric acid solutions respectively, and the acid resistance of the willemite crystalline glaze architectural ceramics obtained was measured to be GLA and GHA level (no obvious visible corrosion at the crystal flower position).

[0100] Example 3

[0101] A method for preparing highly acid-resistant willemite crystalline glaze architectural ceramics by using local phase separation, the specific preparation steps are as follows:

[0102] Step 1: Prepare ceramic tile blanks by dry pressing ceramic blank powder and perform drying.

[0103] Step 2: Apply the base glaze on the surface of the dried brick by spraying. The chemical composition of the base glaze includes: by mass percentage, SiO2 49.7%; Al2O3 30.0%; Fe2O3 0.5%; TiO2 0.1%; CaO 0.8%; MgO 0.4%; K2O 6.0%; Na2O 2.5%; ZrO2 5.5%; loss on ignition 4.5%. The specific gravity of the base glaze is controlled to be 1.45g / cm 3 , glaze weight is 650 g / m 2 .

[0104] Step 3: According to the glue pattern design (the glue pattern is composed of isolated dots arranged in an array, the diameter of the dots is 0.5 mm, and the dot spacing is 2.5 mm), use an inkjet printer to prepare the glue pattern on the surface of the dried base glaze ceramic tile blank. The grayscale of the glue printing is 50%.

[0105] Step 4: Prepare seeding agent particles. Weigh 45 parts by mass of quartz, 10 parts by mass of corundum, 10 parts by mass of TiO2, 9 parts by mass of CaCO3, 1.5 parts by mass of K2CO3, 3.4 parts by mass of Na2CO3, 4.1 parts by mass of zinc borate (2ZnO·3B2O3·3.5H2O), 23.5 parts by mass of ZnO and Sb2O3 respectively, and place them in a ball mill together with 213 parts by mass of corundum grinding balls and 64 parts by mass of water, and perform ball milling mixing (350r / min, ball milling for 1h); after drying, the seeding agent powder is obtained, and it is placed in an alumina crucible for high-temperature heat treatment (heat treatment temperature is 1200℃, insulation time is 30min, and after insulation is completed, it is cooled with the furnace). Subsequently, the high-temperature heat-treated sample is crushed, and 40-50 mesh particles are screened out for use, and the seeding agent particles can be obtained. The chemical composition of the basic seeding agent includes, by mass percentage, SiO2 45%, Al2O3 10%, TiO2 10%, CaO 5%, K2O 1%, Na2O 2%, B2O3 2%, and ZnO 25%. The mass percentage of Sb2O3 in the basic seeding agent is 0.4%.

[0106] Step 5: Apply seeding agent particles on the surface of the brick after the glue pattern is applied. After the glue is cured, use an exhaust fan to remove excess unbonded seeding agent particles.

[0107] Step 6: Prepare crystalline base glaze. Weigh 79 parts by mass of low-temperature frit (CaO-ZnO-BaO is a low-temperature frit, whose chemical composition includes, by mass percentage, SiO2 40%; Al2O3 8%; CaO 15%; MgO 2%; K2O 6%; Na2O 5%; BaO 10%; ZnO 14%), 5 parts by mass of kaolin, 8 parts by mass of ZnO, 5 parts by mass of TiO2, 3 parts by mass of zinc borate, 0.3 parts by mass of sodium tripolyphosphate, and 0.2 parts by mass of sodium carboxymethyl cellulose, and place them in a ball mill for ball milling (the residue on the 325 mesh sieve of the glaze slurry after ball milling is ≤0.5wt%), and control the specific gravity of the glaze slurry to 1.70g / cm by the amount of water added. 3The crystalline base glaze can be prepared for use. The chemical composition of the crystalline base glaze includes, by mass percentage, SiO2 33.46%; Al2O3 8.1%; Fe2O3 0.04%; TiO 25%; CaO 11.8%; MgO 1.6%; K2O 4.9%; Na2O 4%; B2O 32%; ZnO 20.2%; BaO 7.9%; and loss on ignition 1%.

[0108] Step 7: Apply a crystallization base glaze on the surface of the brick with the seeding agent by pouring glaze. The amount of the crystallization base glaze applied is 1000 g / m 2 . This is followed by a drying process.

[0109] Step 8: The dried bricks with the crystalline base glaze applied are fired in a roller kiln at a temperature of 1150°C and a firing time of 60 min.

[0110] Step 9: After the firing is completed, edge grinding and polishing are performed to obtain the highly acid-resistant willemite crystalline glaze architectural ceramics.

[0111] The crystal flower has a distinct flower shape and a diameter of about 3.5 mm. According to GB / T 3810.13-2016 (Part 13 of Test Methods for Ceramic Tiles: Determination of Chemical Corrosion Resistance), the architectural ceramic glaze was immersed in 3 vol% and 18 vol% hydrochloric acid solutions respectively, and the acid resistance of the prepared willemite crystalline glaze architectural ceramics was measured to be GLA and GHA level (no obvious visible corrosion at the crystal flower position).

[0112] Comparative Example 1

[0113] The technical scheme of Comparative Example 1 is basically the same as that of Example 1, with the main difference being that Comparative Example 1 uses 30-40 mesh ZnO particles as seeding agent.

[0114] The flower shape of the prepared willemite crystalline glaze architectural ceramics is obvious, and the diameter of the flower is about 2.1 mm. The microstructure of the amorphous phase on the surface of the flower is measured by SEM, such as Figure 8 As shown, the amorphous phase on the surface of the crystal flower presents a worm-like network connected phase structure. The continuous distribution of the ZnO-rich and SiO2-Al2O3-poor phases and their poor chemical stability easily lead to a decrease in the acid resistance of the amorphous phase, which is not conducive to improving the acid resistance of the willemite crystalline glaze. Further, according to GB / T 3810.13-2016 (Part 13 of the test method for ceramic tiles: Determination of chemical corrosion resistance), the building ceramic glaze was immersed in 3 vol% and 18 vol% hydrochloric acid solutions, respectively. The acid resistance of the willemite crystalline glaze building ceramics obtained was measured to be only GLC and GHB level (there was visible damage on the surface of the crystal flower position).

[0115] Comparative Example 2

[0116] The technical scheme of Comparative Example 1 is basically the same as that of Example 1, with the main difference being that Comparative Example 2 uses 30-40 mesh Zn2SiO4 particles as the seeding agent.

[0117] The flower shape of the willemite crystal glaze architectural ceramics is obvious, and the diameter of the crystal is about 2.8 mm. According to GB / T 3810.13-2016 (Part 13 of Test Methods for Ceramic Tiles: Determination of Chemical Corrosion Resistance), the glaze of architectural ceramics was immersed in 3 vol% and 18 vol% hydrochloric acid solutions, respectively. The acid resistance of the willemite crystal glaze architectural ceramics was measured to be only GLC and GHB level (there was visible damage on the surface of the crystal position).

[0118] Comparative Example 3

[0119] The technical solutions of Comparative Example 1 and Example 1 are basically the same, with the main difference being that the use of seeding agent particles is omitted in Comparative Example 3, and the sintering of Comparative Example 3 adopts a two-step sintering process (first, heating to 1160°C, keeping warm for 10 minutes, and then cooling to 1000°C, keeping warm for 30 minutes).

[0120] The crystal flowers of the prepared willemite crystalline glaze architectural ceramics are randomly distributed and overlapped in large quantities, resulting in poor decorative effect of the crystal flowers. At the same time, the glaze of the architectural ceramics was immersed in 3 vol% and 18 vol% hydrochloric acid solutions, respectively, and the acid resistance of the prepared willemite crystalline glaze architectural ceramics was measured to be only GLC and GHC levels (there was visible damage on the surface of the crystal flower position).

Claims

1. A method for preparing highly acid-resistant willemite crystalline glaze architectural ceramics by using local phase separation, characterized in that: The method comprises the following steps: Applying base glaze to the surface of ceramic tile green; inkjet printing a glue pattern on the surface of the brick after applying the base glaze; Applying seeding agent particles on the surface of the brick after the glue pattern is inkjet printed, and removing excess seeding agent particles that are not bonded after the glue is cured; the seeding agent particles are composed of a basic seeding agent and Sb2O3, wherein the chemical composition of the basic seeding agent includes: in terms of mass percentage, SiO2 30-45%; Al2O3 10-15%; TiO2 10-15%; CaO 5-10%; K2O 1-4%; Na2O 2-4%; B2O3 2-5%; ZnO 25-40%; the mass percentage of Sb2O3 in the basic seeding agent is 0.3-0.5%; the particle size of the seeding agent particles is 30-60 mesh; the preparation method of the seeding agent particles comprises: uniformly mixing the mineral composition of the basic seeding agent with Sb2O3, heat treating at 1150-1250°C for 10-120 min, cooling to room temperature with the furnace, and crushing and screening to obtain the seeding agent particles; A crystalline base glaze is applied on the surface of the brick after applying the seeding agent particles; the chemical composition of the crystalline base glaze includes, by mass percentage, SiO2 18-37%; Al2O3 5-10%; Fe2O3 0.04-0.1%; TiO2 5-10%; CaO 6-12%; MgO 0.8-2.0%; K2O 2.5-5%; Na2O 2-4%; B2O3 0.5-2.0%; ZnO 14-35%; BaO 4-8%; loss on ignition 0.7-1.7%; the mineral composition of the crystalline base glaze includes, by mass percentage, 56-79 parts of low-temperature frit, 5-10 parts of kaolin, 8-20 parts of ZnO, 5-10 parts of TiO2, and 1-4 parts of zinc borate; wherein the chemical composition of the low-temperature frit includes, by mass percentage, SiO2 35-45%; Al2O3 5-10%; CaO 10~20%; MgO 1~5%; K2O 5~8%; Na2O 3~8%; BaO 8~13%; ZnO 10~20%; The brick blank after applying the crystallized base glaze is dried, fired and polished to obtain the highly acid-resistant willemite crystallized glaze architectural ceramics; the firing temperature is 1140-1160° C., and the firing time is 50-70 min.

2. The method according to claim 1, characterized in that The mineral composition of the basic seeding agent includes, by mass, 30 to 45 parts of quartz, 10 to 15 parts of corundum, 10 to 15 parts of TiO2, 9 to 18 parts of CaCO3, 1 to 6 parts of K2CO3, 3 to 10 parts of Na2CO3, 4 to 11 parts of zinc borate, and 23 to 40 parts of ZnO.

3. The method according to claim 1, characterized in that The grayscale of the glue pattern is 40-60%.

4. The method according to claim 1, characterized in that The crystalline base glaze is applied by pouring or spraying; the specific gravity of the crystalline base glaze is 1.60-1.80 g / cm 3 , glaze application amount is 800~1200 g / m 2 .

5. The method according to claim 1, characterized in that The glue pattern is a one-dimensional line or two-dimensional area pattern composed of isolated dots arranged in an array.

6. The method according to claim 1, characterized in that The glaze surface of the highly acid-resistant willemite crystalline glaze architectural ceramic contains willemite crystal flowers composed of nano-microcrystalline willemite fibers and amorphous phases interlaced.

7. The method according to claim 6, characterized in that The amorphous phase has a spherical droplet dispersed phase structure, including a ZnO-poor SiO2-Al2O3-rich base phase and a ZnO-rich SiO2-Al2O3-poor phase dispersed in the ZnO-poor SiO2-Al2O3-rich base phase in the form of isolated droplets.

8. The method according to claim 1, characterized in that The chemical composition of the base glaze includes, by mass percentage, SiO2 49-60%, Al2O3 25-30%, Fe2O3 0.2-0.5%, TiO2 0.1-0.2%, CaO 0.3-0.8%, MgO 0.1-0.5%, K2O 2-6%, Na2O 2-3.5%, ZrO2 4-8%, and loss on ignition 2-5%.

9. The method according to claim 1, characterized in that The base glaze is applied by spraying or pouring; the specific gravity of the base glaze is 1.40-1.45 g / cm 3 , glaze application amount is 500~650 g / m 2 .

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