A boccaro product for promoting wine aging and a preparation method thereof

Abstract

This invention provides a Zisha (purple clay) product for promoting the aging of liquor and its preparation method. By introducing pomelo peel powder into the modified Zisha clay slurry, it synergistically constructs a multi-scale permeable pore structure with rice husk ash, achieving controllable micro-oxygen circulation. The pectin in the pomelo peel powder chelates a small amount of unremoved iron ions, transforming these iron ions into highly dispersed nano-oxides after firing. Carbonized residues and trace elements from the rice husk ash coexist on the pore surface, providing a favorable microenvironment for the aging reaction in the liquor. During molding, molding aids are added, combined with vacuum injection and multi-stage atmosphere firing, to enhance the strength and toughness of the clay body, forming a dual-pore structure combining open and closed elements. The resulting Zisha product has a dense structure and high strength, can controllably promote the aging of liquor, making the liquor mellow and sweet, and is suitable for Zisha products such as tea canisters and teapots.

Description

Technical Field

[0001] This invention relates to the technical field of Zisha (purple clay) product preparation, specifically to a Zisha product for promoting the aging of wine and its preparation method. Background Technology

[0002] The use of Zisha (purple clay) for making wine containers has a long history in my country. Its unique double-pore structure gives the containers excellent breathability, allowing for a "breathing but not liquid" micro-oxygen cycle during the aging process of wine. This effectively promotes the oxidation and esterification reactions of alcohols and aldehydes in the wine, thereby accelerating the aging process and enhancing the smoothness of the taste and the complexity of the aroma. For this reason, Zisha pottery jars are widely recognized as ideal equipment for aging baijiu (Chinese white liquor), enjoying the reputation of "breathing pottery jars" in the industry. However, in long-term production practice and practical application, traditional Zisha products and their preparation processes still have certain technical defects, which restrict their full functionality.

[0003] The primary problem with existing technologies lies in the inadequacy of clay purification and processing techniques. Naturally occurring iron impurities in Zisha clay are a key factor affecting the final quality of the containers. While traditional wet absorption methods can remove some free iron, their efficiency is extremely limited for removing fine iron-containing minerals coated on the surface of clay particles. Residual iron impurities, after high-temperature firing, not only form surface defects such as spots, but more importantly, excessive iron is chemically reactive. During long-term storage of wine, it may react with trace components in the wine, causing discoloration, such as reddening, blackening, or turbidity, thus damaging the wine's quality and flavor.

[0004] Secondly, regarding clay modification, traditional Zisha (purple clay) formulas often rely on single or a few natural minerals, resulting in relatively limited functionality. To enhance the aging effect of the container, it is generally desirable for it to possess suitable adsorption and permeability properties, but traditional processes struggle to precisely control these microscopic characteristics. For example, the container needs a certain adsorption capacity to remove off-flavors from the wine, while simultaneously avoiding excessive adsorption of beneficial aroma substances. In the field of Zisha containers used for long-term wine storage, to achieve controllable micro-oxygen circulation and promote wine aging, plant fiber pore-forming agents are commonly introduced into the Zisha body. After firing, the fibers oxidize and escape, forming permeable channels. Common plant fiber pore-forming agents include coconut shell powder and corn stalk powder; however, these materials have certain limitations: coconut shell powder has a low apparent porosity and limited connectivity after firing; while corn stalk powder can form channels, it reduces the mechanical strength of the clay body to some extent. Therefore, existing pore-forming agents cannot simultaneously achieve the dual goals of "high interconnected porosity" and "maintaining sufficient mechanical strength." There is an urgent need for a natural material that can both construct interconnected channels to promote the aging of wine and has good compatibility with Zisha clay.

[0005] The microscopic pore structure of traditional Zisha clay is mostly formed naturally, and its pore size distribution, porosity and connectivity are difficult to control. This results in either insufficient air permeability, affecting aging efficiency, or excessive air permeability, causing disordered volatilization of aroma substances in the wine.

[0006] Furthermore, the inherent mechanical properties of traditional Zisha (purple clay) products constitute another major drawback. Zisha, a traditional ceramic material, is inherently brittle, making its containers prone to breakage during handling, use, and long-term storage. Due to the simple composition of the clay and the lack of effective toughening mechanisms, microcracks generated during firing, cooling, or long-term use due to temperature changes or external forces easily propagate, ultimately leading to container cracking. Therefore, how to effectively improve the toughness and impact resistance of Zisha without altering its fundamental properties is also a key research focus of this application.

[0007] Furthermore, the precision of the molding and drying processes is also crucial to the yield rate. Traditional slip casting relies heavily on experience, making it difficult to maintain consistent slurry fluidity and stability, which can easily lead to uneven internal structure and hidden defects in the green body. In the drying stage, the lack of precise segmented control over temperature and humidity results in inconsistent shrinkage rates between the inside and outside of the wet green body during dehydration, easily causing stress concentration and forming microcracks that are difficult to detect with the naked eye. These microcracks will become the source of fracture during subsequent firing and use, severely reducing the lifespan and reliability of the container.

[0008] For a long time, the firing of Zisha (purple clay) vessels has mostly relied on a single oxidizing atmosphere or atmosphere adjustment based solely on experience. While single oxidizing firing is stable, it cannot effectively control the valence state and distribution of iron, and also limits the formation of specific crystal phases. Furthermore, the lack of precise pressure control, especially during the heat preservation stage where a specific atmosphere needs to be maintained, leads to pressure fluctuations within the kiln, resulting in the disordered entry of outside air or excessive heat loss from the kiln. This not only disrupts the stability of the atmosphere but also renders the final structure of the clay body, such as the crucial ratio of "open pores" to "closed pores," uncontrollable.

[0009] In summary, existing technologies have certain shortcomings in areas such as iron removal from raw materials, functional modification of clay, enhancement of mechanical properties, precision of molding and drying, and control of firing atmosphere. Therefore, developing a process for preparing Zisha (purple clay) products that can systematically modify the material from its source, while retaining the excellent traditional characteristics of Zisha and overcoming the aforementioned deficiencies, and achieving scientific promotion and effective control of the aging process of wine, has become a key issue urgently needing to be addressed by those skilled in the art. Solving this problem will not only significantly improve the yield, service life, and artistic value of Zisha products, but will also provide the wine aging industry with a new type of wine storage equipment with superior performance and controllable functions. This has significant practical implications and broad application prospects for improving wine quality, ensuring wine safety, and promoting the deep integration of traditional brewing techniques with modern materials science. Summary of the Invention

[0010] The technical problem to be solved by the present invention is to improve the defects of existing Zisha products in promoting the aging of wine, such as the aging effect and firing process, and to provide a Zisha product and its preparation method that can efficiently promote the aging of wine, with a short aging cycle, stable effect and controllable preparation process.

[0011] To solve the above-mentioned technical problems, the present invention provides the following technical solution:

[0012] Option 1: A method for preparing Zisha (purple clay) products that promote the aging of wine, comprising the following steps:

[0013] S1. Raw material processing: After the purple clay ore has been exposed to the open air and weathered for more than 3 months, auxiliary materials are added for crushing, wet absorption to remove iron, and ultrasonic treatment.

[0014] S2. First vacuum plowing and aging: The ultrasonically treated material is crushed through a 40-60 mesh sieve, ball-milled, sieved, filtered, vacuum plowed and aged for 7-15 days.

[0015] S3. Modification, Second Vacuuming, and Aging of Purple Clay Slurry: 1-3% zeolite powder, 0.2-0.5% plant fiber reinforcing agent, 0.5-1% barium carbonate, and 0.2-0.5% rice husk ash (by mass percentage) are pre-dry mixed evenly and then sprinkled into the purple clay slurry. The stirring speed is controlled at 80-120 rpm. After stirring for 20-30 minutes, a second vacuum kneading is carried out with a vacuum degree of 700-740 mmHg. Then, the mixture is sealed and aged for 15-30 days.

[0016] S4. Shaping: Add shaping aids to the purple clay slurry after the second aging, and use vacuum casting process to make the blank;

[0017] S5. Drying: The shaped wet blank is dried in two stages under controlled temperature and humidity until the moisture content is below 3%;

[0018] S6. Multi-stage firing: First, pre-firing is performed with a first target temperature of 800℃±10℃. The heating rate is 2℃ / min from room temperature to 300℃, 3℃ / min from 300℃ to 600℃, and 2℃ / min from 600℃ to the first target temperature. After reaching the first target temperature, the temperature is held for 60 minutes. After pre-firing is completed and cooled to room temperature, a second firing is performed with a second target temperature of 1130℃±20℃. The heating rate is 3℃ / min from room temperature to 600℃, 4℃ / min from 600℃ to 950℃, and 2℃ / min from 950℃ to the second target temperature. After reaching the second target temperature, the temperature is held for 90 minutes.

[0019] Furthermore, the plant fiber reinforcing agent in step S3 is grapefruit peel powder;

[0020] Furthermore, the 90-minute holding period after the second firing reaches the second target temperature in step S6 includes: using an oxidizing atmosphere for the first 30 minutes of the holding period, with the kiln pressure adjusted to -5 to -10 Pa, and switching to a weak reducing atmosphere for the next 60 minutes, with the kiln pressure adjusted to 5-10 Pa.

[0021] Further, step S1, which involves adding auxiliary materials for crushing, wet adsorption iron removal, and ultrasonic treatment, includes: crushing 95-100 parts of purple clay ore, 1-5 parts of pyrophyllite, 1-2 parts of sodium bentonite, and 0.3-0.5 parts of humic acid; then removing iron using wet adsorption to control the slurry specific gravity below 1.7; performing magnetic separation using a permanent magnet flat plate magnetic separator; and simultaneously performing ultrasonic treatment at a frequency of 20-40kHz and a power density of 0.3-0.5W / cm³. 3 .

[0022] Further, the ball milling, sieving, filter pressing, vacuum slurry preparation and aging in step S2 include: ball milling the material at a ratio of material:water:ball = 1:0.8:1.5 for 12-24 hours until the fineness reaches 250 mesh; passing the ball-milled slurry through a 200-mesh vibrating screen, and then sending it to a filter press after 2-3 magnetic separations to press it into mud cakes with a moisture content of 21%; the mud cakes undergo a first vacuum slurry preparation, with the vacuum degree controlled at 700-740 mmHg, and then are sealed for the first aging for 7-15 days.

[0023] Further, the step S4, which involves adding molding aids and using a vacuum grouting process to form the blank, includes adding a stabilizer (0.3-0.5% of the total mass of the purple clay slurry), a sintering aid (0.5-0.8%), a toughening agent (0.3-0.5%), polyethylene glycol (0.5-1.0%), and silica (1.5%). After mixing, the mixture is ball-milled for 2-4 hours at a speed of 30-40 rpm. The molding process uses vacuum grouting. Water is added to the ball-milled purple clay to control its moisture content. The clay content is 28%-32%, and sodium silicate is added at a mass ratio of 0.2%-0.3% as a diluent. The mixture is stirred at 60-80 rpm to adjust the fluidity. The clay slurry is poured into a plaster mold and placed on a vacuum vibration table for slurrying. The vacuum degree is -0.08MPa, the vibration frequency is 50Hz, and the process is continued for 3-5 minutes. After slurrying, the mold is left to stand for 30-40 minutes. When the thickness of the clay body reaches 4-6mm, the excess clay slurry is poured out. The mold is then demolded after curing for another 2-3 hours.

[0024] Furthermore, the stabilizer is yttrium oxide, the sintering aid is titanium oxide, and the toughening agent is zirconium dioxide.

[0025] Furthermore, the two-stage temperature and humidity controlled drying in step S5 includes: the first stage drying temperature is controlled at 30℃±2℃, humidity at 70%±5%, and the duration is 24 hours; the second stage drying temperature is controlled at 38℃±2℃, humidity at 60%±5%, and the duration is 36 hours.

[0026] Option 2: A purple clay product for promoting the aging of wine, prepared by any of the above methods, wherein the purple clay product includes, but is not limited to, wine containers, tea canisters, teapots, teacups and ornaments.

[0027] Option 3: The application of the aforementioned Zisha (purple clay) products that promote the aging of wine in the aging of wine and beverages.

[0028] The advantages and beneficial effects of this invention are as follows:

[0029] 1. This invention discloses a Zisha (purple clay) product for promoting the aging of wine and its preparation method, improving upon the problems of traditional Zisha containers being functionally limited, having slow aging effects, and being difficult to control when used for wine storage. The Zisha product obtained by this invention not only has a dense structure, high strength, and long service life, but also scientifically and controllably promotes the aging of wine, solving the problem of poor aging effects of traditional containers, and providing a more superior functional container for wine storage and aging. At the same time, the preparation method of this invention is also applicable to Zisha products such as tea canisters, teapots, teacups, and decorative items, significantly improving their structural strength, breathability control, and surface texture, thus broadening the application range of high-performance Zisha materials.

[0030] 2. This invention introduces pomelo peel powder as a plant fiber reinforcing agent during the modification stage of Zisha clay slurry. Its unique structure, after firing, can act as a "structural template" to form an interconnected network of pores in the clay body, achieving a balance between high porosity and high strength. During the multi-stage firing process, the pomelo peel powder undergoes a low-temperature stage (room temperature - 300℃) for moisture evaporation, a medium-temperature stage (300-600℃) for organic matter pyrolysis and carbonization to form a carbon skeleton, and a high-temperature stage (600-1130℃) for the complete oxidation and escape of the carbon skeleton, which is then "frozen" in the clay body. By controlling the temperature in stages, the cellulose, pectin, and other organic matter and carbonates in the pomelo peel powder are fully decomposed and oxidized, avoiding defects caused by the rapid escape of gases during the high-temperature stage. This pore network, together with rice husk ash, forms a multi-scale pore network structure of "main pores + micropores". The main pores formed by grapefruit peel powder serve as the main channels for micro-oxygen circulation, while the micropores formed by rice husk ash increase the specific surface area and provide more reaction interfaces for esterification reactions. Together, they ensure that trace amounts of oxygen can continuously enter the container at an appropriate rate to promote the aging of the wine, while preventing excessive volatilization of aroma components. The trace carbon residue left after burning grapefruit peel powder and the residue of rice husk ash coexist on the surface of the pores, which can increase the contact area between the wine and the pore surface, providing a more favorable microenvironment for aging reactions such as alcoholysis and esterification. This helps to generate more ester aroma substances within the same storage time, making the wine smoother and enhancing its sweetness and complexity. In addition, the amorphous silica in the modified powder has a certain reactivity, which helps to generate the mullite crystal phase. After being dry-mixed evenly, these modified powders are sprinkled into the slurry and supplemented with secondary vacuum kneading and secondary aging, so that the functional components are highly dispersed and fully integrated in the slurry, which significantly enhances the mechanical properties after sintering and further improves the structural strength of the matrix.

[0031] 3. This invention employs a wet absorption method for iron removal during the raw material processing stage. Utilizing the principle of physical magnetic separation, it effectively removes strongly magnetic iron-containing minerals, thereby reducing the total iron content to a level that does not affect the appearance of the finished product. For free iron ions in weakly magnetic or non-magnetic iron-containing minerals that are difficult to capture using wet iron removal, the pectin component in grapefruit peel powder plays a certain chelating role. During the clay preparation stage, it can capture free iron ions, forming stable pectin-iron complexes. This uniformly disperses and fixes the iron ions within the organic framework of the grapefruit peel powder, thus preventing localized accumulation of iron impurities during subsequent firing and avoiding color defects or adverse reactions with the wine. During firing, the organic components of the grapefruit peel powder completely decompose, and the iron element is transformed into highly dispersed nano-oxides. These iron oxides neither exhibit color nor react with trace components in the wine, thus ensuring the purity and color stability of the wine during long-term storage.

[0032] 4. In the raw material processing stage, this invention preferentially uses purple clay ore and pyrophyllite as base materials, with the additional addition of sodium-based bentonite and humic acid. The introduction of pyrophyllite improves the high-temperature stability and resistance to rapid heating and cooling of the green body, while humic acid, as a natural diluent and grinding aid, effectively improves the fluidity and plasticity of the slurry. Furthermore, ultrasonic treatment is introduced into the traditional wet adsorption method for iron removal. The cavitation effect generated by its high-frequency vibration can effectively dissociate iron-containing mineral particles wrapped on the surface of clay minerals, improving the iron removal efficiency of subsequent magnetic separation. Subsequently, ball milling, sieving, vacuum kneading, and aging allow the clay to be fully hydrated and dust-removed, improving the processing properties of the clay and ensuring the uniformity and stability of subsequent modification and molding.

[0033] 5. In the forming process, yttrium oxide, titanium dioxide, and zirconium dioxide work synergistically: yttrium oxide acts as a stabilizer, working with zirconium dioxide to stabilize the tetragonal phase to room temperature, preventing phase transformation cracking and lowering the sintering temperature; titanium dioxide acts as a sintering aid, improving sintering activity and promoting densification; zirconium dioxide acts as a toughening agent, absorbing crack energy through phase transformation to enhance toughness and improve the brittleness of traditional Zisha clay. Furthermore, polyethylene glycol regulates the plasticity of the clay, silica optimizes the glass phase content to balance density and porosity, and vacuum slurry casting combined with vibration molding ensures the integrity and density of complex shapes, avoiding porosity and delamination defects.

[0034] 6. The drying process adopts a staged gradient drying method, which effectively avoids hidden cracks and deformations caused by the difference in shrinkage stress between the inside and outside of the wet blank, ensuring the integrity of the green blank and providing a high-quality blank for subsequent firing.

[0035] 7. Furthermore, during the 90-minute holding period of the second firing, staged atmosphere control is implemented. The first 30 minutes utilize an oxidizing atmosphere combined with slight negative pressure to ensure complete combustion of the grapefruit peel powder's carbon skeleton and the formation of interconnected channels, while simultaneously saturating the crystal lattice with oxygen. The following 60 minutes switch to a weak reducing atmosphere and adjust the kiln pressure to slight positive pressure. On one hand, under the weak reducing atmosphere, some iron ions in the clay are reduced, altering its coloration; on the other hand, the slight positive pressure effectively prevents the intrusion of external oxygen, maintaining a stable reducing environment and promoting the formation and grain boundary bonding of specific low-melting-point eutectics. These low-melting-point eutectics partially melt during the holding process and migrate to the edges of some open pores, causing them to shrink or close, thus forming a dual-pore structure combining "open" and "closed" pores. The open pores serve as the main channels for trace oxygen exchange, ensuring the slow oxidation required for the wine; the closed pores prevent the rapid escape of aroma components, thereby effectively locking in the aroma while promoting the aging of the wine.

[0036] 8. In summary, this invention deeply integrates ultrasonic-assisted iron removal, pore-forming with natural composite modifiers, toughening and reinforcement with rare earth oxides, gradient drying, and multi-stage atmosphere firing to prepare Zisha (purple clay) products that possess high strength, high toughness, controllable micro-nano porous structures, and the ability to actively participate in and promote the physicochemical reactions of the wine. This not only significantly extends the service life of the containers but also achieves the scientific promotion and control of the wine aging process. Attached Figure Description

[0037] Figure 1 The purple clay wine jar prepared in Example 3. Detailed Implementation

[0038] The present invention will be further described in detail below with reference to the embodiments. Figure 1 This is a diagram of the purple clay wine jar produced according to the present invention. The purple clay ore used in this application was purchased from the Huanglongshan mining area in Dingshu Town, Yixing City, Jiangsu Province. In the following embodiments, the purple clay ore raw materials underwent the following raw material processing, first vacuum mud-making, and aging process: The purple clay ore was exposed to the open air for weathering for more than 3 months. 10 kg of purple clay ore and 0.3 kg of pyrophyllite were selected as the base material, with 0.15 kg of sodium-based bentonite and 0.04 kg of humic acid added for crushing. Iron was removed using a wet absorption method, and the specific gravity of the mud slurry was controlled below 1.7. Magnetic separation was performed using a permanent magnet flat plate magnetic separator, and ultrasonic treatment was simultaneously applied at a frequency of 30 kHz and a power density of 0.4 W / cm³. 3 The material after magnetic separation is crushed and passed through a 50-mesh sieve, then fed into a ball mill and milled for 18 hours at a ratio of material:water:ball = 1:0.8:1.5 until the fineness reaches 250 mesh. The slurry after ball milling is passed through a 200-mesh vibrating sieve, and then sent to a filter press after three magnetic separations to be pressed into mud cakes with a moisture content of 21%. The mud cakes are then subjected to a first vacuum plowing, with the vacuum degree controlled at 720 mmHg, and then sealed for the first aging for 12 days.

[0039] Example 1

[0040] (1) Modification of Zisha clay slurry: 2% of zeolite powder, 0.3% of grapefruit peel powder, 0.8% of barium carbonate and 0.3% of rice husk ash were pre-dry mixed evenly and then sprinkled into the aged Zisha clay slurry. The stirring speed was controlled at 100 rpm. After stirring for 25 minutes, the clay was vacuum kneaded for the second time with a vacuum degree of 720 mmHg. Then it was sealed and aged for the second time for 22 days.

[0041] (2) Molding: Take the purple clay slurry after the second aging, add 0.4% yttrium oxide, 0.6% titanium oxide, 0.4% zirconium dioxide, 0.8% polyethylene glycol, and 1.5% silicon dioxide by mass of the total purple clay slurry, mix and ball mill for 3 hours at a speed of 35 rpm. The molding adopts the vacuum grouting process. Add water to the ball-milled purple clay to control the water content to 30%, and add sodium silicate by mass of 0.25% as a diluent. Stir and adjust the fluidity at a speed of 70 rpm. Pour the purple clay slurry into the plaster mold and place it on a vacuum vibration table for grouting. The vacuum degree is -0.08 MPa, the vibration frequency is 50 Hz, and it lasts for 4 minutes. After grouting, let it stand for 35 minutes. When the thickness of the blank reaches 5 mm, pour out the excess slurry and continue to cure for 2 hours before demolding.

[0042] (3) Drying: The temperature is controlled at 30℃ and the humidity at 70% for 24 hours in the first stage; the temperature is controlled at 38℃ and the humidity at 60% for 36 hours in the second stage, until the moisture content of the green body is below 3%.

[0043] (4) Multi-stage firing: First, pre-firing is carried out. The first target temperature is 800℃. The heating rate is 2℃ / min in the range from room temperature to 300℃, 3℃ / min in the range from 300 to 600℃, and 2℃ / min in the range from 600 to 800℃. The temperature is held at 800℃ for 60 minutes. After the pre-firing is completed and cooled to room temperature, the second firing is carried out. The second target temperature is 1130℃. The heating rate is 3℃ / min in the range from room temperature to 600℃, 4℃ / min in the range from 600 to 950℃, and 2℃ / min in the range from 950 to 1130℃. The temperature is held at 1130℃ for 90 minutes. An oxidizing atmosphere is used for the first 30 minutes of holding, and the pressure inside the kiln is adjusted to -8Pa. The weak reducing atmosphere is switched to the last 60 minutes, and the pressure inside the kiln is adjusted to 8Pa.

[0044] Example 2

[0045] (1) Modification of Zisha clay slurry: 1% of zeolite powder, 0.5% of grapefruit peel powder, 0.5% of barium carbonate and 0.5% of rice husk ash are pre-dry mixed evenly and then sprinkled into the aged Zisha clay slurry. The stirring speed is controlled at 80 rpm. After stirring for 30 minutes, the clay is vacuum kneaded for the second time with a vacuum degree of 700 mmHg. Then it is sealed and aged for the second time for 30 days.

[0046] (2) Molding: Take the purple clay slurry after the second aging, add 0.3% yttrium oxide, 0.8% titanium oxide, 0.3% zirconium dioxide, 1.0% polyethylene glycol, and 1.5% silicon dioxide by mass of the total purple clay slurry, mix and ball mill for 2 hours at a speed of 40 rpm. The molding adopts the vacuum injection process. Add water to the ball-milled purple clay to control the water content to 28%, and add sodium silicate by mass of 0.3% as a diluent. Stir and adjust the fluidity at a speed of 60 rpm. Inject the purple clay slurry into the plaster mold and place it on a vacuum vibration table for injection. The vacuum degree is -0.08 MPa, the vibration frequency is 50 Hz, and it lasts for 3 minutes. After injection, let it stand for 40 minutes. When the thickness of the blank reaches 4 mm, pour out the excess slurry and continue to cure for 3 hours before demolding.

[0047] (3) Drying: The temperature is controlled at 32℃ and the humidity is 75% in the first stage, and the duration is 24 hours; the temperature is controlled at 36℃ and the humidity is 65% in the second stage, and the duration is 36 hours, until the moisture content of the green body is below 3%.

[0048] (4) Multi-stage firing: First, pre-firing is carried out. The first target temperature is 810℃. The heating rate is 2℃ / min in the range from room temperature to 300℃, 3℃ / min in the range from 300 to 600℃, and 2℃ / min in the range from 600 to 810℃. The temperature is held at 810℃ for 60 minutes. After the pre-firing is completed and cooled to room temperature, the second firing is carried out. The second target temperature is 1110℃. The heating rate is 3℃ / min in the range from room temperature to 600℃, 4℃ / min in the range from 600 to 950℃, and 2℃ / min in the range from 950 to 1110℃. The temperature is held at 1110℃ for 90 minutes. An oxidizing atmosphere is used for the first 30 minutes of holding, and the pressure inside the kiln is adjusted to -10Pa. The weak reducing atmosphere is switched to the last 60 minutes, and the pressure inside the kiln is adjusted to 5Pa.

[0049] Example 3

[0050] (1) Modification of Zisha clay slurry: 3% of zeolite powder, 0.2% of pomelo peel powder, 1% of barium carbonate and 0.2% of rice husk ash were pre-dry mixed evenly and then sprinkled into the aged Zisha clay slurry. The stirring speed was controlled at 120 rpm. After stirring for 20 minutes, the clay was vacuum kneaded for the second time with a vacuum degree of 740 mmHg. Then it was sealed and aged for the second time for 15 days.

[0051] (2) Molding: Take the purple clay slurry after the second aging, add 0.5% yttrium oxide, 0.5% titanium oxide, 0.5% zirconium dioxide, 0.5% polyethylene glycol, and 1.5% silicon dioxide according to the total mass ratio of the purple clay slurry, mix and ball mill for 4 hours at a speed of 30 rpm. The molding adopts the vacuum grouting process. Add water to the ball-milled purple clay to control the water content to 32%, and add sodium silicate according to the mass ratio of the purple clay as a diluent. Stir and adjust the fluidity at a speed of 80 rpm. Pour the purple clay slurry into the plaster mold and place it on the vacuum vibration table for grouting. The vacuum degree is -0.08 MPa, the vibration frequency is 50 Hz, and it lasts for 5 minutes. After grouting, let it stand for 30 minutes. When the thickness of the blank reaches 6 mm, pour out the excess slurry and continue to cure for 2 hours before demolding.

[0052] (3) Drying: The temperature is controlled at 28℃ and the humidity at 65% for 24 hours in the first stage; the temperature is controlled at 40℃ and the humidity at 55% for 36 hours in the second stage, until the moisture content of the green body is below 3%.

[0053] (4) Multi-stage firing: First, pre-firing is carried out. The first target temperature is 790℃. The heating rate is 2℃ / min in the range from room temperature to 300℃, 3℃ / min in the range from 300 to 600℃, and 2℃ / min in the range from 600 to 790℃. The temperature is held at 790℃ for 60 minutes. After the pre-firing is completed and cooled to room temperature, the second firing is carried out. The second target temperature is 1150℃. The heating rate is 3℃ / min in the range from room temperature to 600℃, 4℃ / min in the range from 600 to 950℃, and 2℃ / min in the range from 950 to 1150℃. The temperature is held at 1150℃ for 90 minutes. An oxidizing atmosphere is used for the first 30 minutes of holding, and the pressure inside the kiln is adjusted to -5Pa. The weak reducing atmosphere is switched to the last 60 minutes, and the pressure inside the kiln is adjusted to 10Pa.

[0054] Comparative Example 1

[0055] Modification of Zisha clay slurry: 2% zeolite powder, 0.8% barium carbonate and 0.6% rice husk ash by mass of Zisha clay slurry were pre-mixed evenly and then sprinkled into the aged Zisha clay slurry. The stirring speed was controlled at 100 rpm and stirred for 25 minutes. Then, a second vacuum kneading was carried out with a vacuum degree of 720 mmHg. After that, it was sealed and aged for a second time for 22 days. The rest of the shaping, drying and multi-stage firing were the same as in Example 1.

[0056] Comparative Example 2

[0057] The difference between this comparative example and Example 1 is that in this comparative example, the grapefruit peel powder in the purple clay slurry modification step is replaced with coconut shell powder; the rest is the same as in Example 1.

[0058] Comparative Example 3

[0059] The difference between this comparative example and Example 1 is that in this comparative example, yttrium oxide in the molding process is replaced with cerium oxide; otherwise, it is the same as in Example 1.

[0060] Comparative Example 4

[0061] The difference between this comparative example and Example 1 is that in this comparative example, the yttrium oxide in the molding process is replaced with cerium oxide, and the titanium oxide is replaced with magnesium oxide; otherwise, it is the same as in Example 1.

[0062] Comparative Example 5

[0063] (1) Modification of Zisha clay slurry: 2% of zeolite powder, 0.3% of grapefruit peel powder, 0.8% of barium carbonate and 0.3% of rice husk ash were pre-dry mixed evenly and then sprinkled into the aged Zisha clay slurry. The stirring speed was controlled at 100 rpm. After stirring for 25 minutes, the clay was vacuum kneaded for the second time with a vacuum degree of 720 mmHg. Then it was sealed and aged for the second time for 22 days.

[0064] (2) Molding: Take the purple clay slurry after the second aging, add 0.4% yttrium oxide, 0.6% titanium oxide, 0.4% zirconium dioxide, 0.8% polyethylene glycol, and 1.5% silicon dioxide by mass of the total purple clay slurry, mix and ball mill for 3 hours at a speed of 35 rpm. The molding adopts the vacuum grouting process. Add water to the ball-milled purple clay to control the water content to 30%, and add sodium silicate by mass of 0.25% as a diluent. Stir and adjust the fluidity at a speed of 70 rpm. Pour the purple clay slurry into the plaster mold and place it on a vacuum vibration table for grouting. The vacuum degree is -0.08 MPa, the vibration frequency is 50 Hz, and it lasts for 4 minutes. After grouting, let it stand for 35 minutes. When the thickness of the blank reaches 5 mm, pour out the excess slurry and continue to cure for 2 hours before demolding.

[0065] (3) Drying: The temperature is controlled at 30℃ and the humidity at 70% for 24 hours in the first stage; the temperature is controlled at 38℃ and the humidity at 60% for 36 hours in the second stage, until the moisture content of the green body is below 3%.

[0066] (4) Firing: The temperature is raised from room temperature to 600℃ at a rate of 2℃ / min, then to 950℃ at a rate of 4℃ / min, and then to 1130℃ at a rate of 2℃ / min. The temperature is held at 1130℃ for 90 minutes. During the holding period, an oxidizing atmosphere is maintained throughout, and the pressure inside the kiln is kept constant at -5Pa. The kiln is cooled after firing.

[0067] Experiment 1: Performance Testing

[0068] (1) Apparent porosity test: Standard test blocks were cut from the uniform wall thickness of the belly of each batch of fired purple clay products. The test blocks were cubes with a side length of 40mm×40mm×40mm or round pieces with a diameter of 50mm and a thickness of 10-15mm. The surface was required to be flat and smooth, without any visible defects. Five blocks were randomly selected from each batch for parallel testing. Before the test, the test blocks were placed in an electric heating drying oven and dried to constant weight at 105℃±5℃. After being taken out, they were placed in a desiccator to cool to room temperature. The mass of the dried test block was weighed using an analytical balance with an accuracy of 0.01g and recorded as m1. The dried test block was placed in a vacuum container and evacuated until the residual pressure was less than 20mmHg and maintained for 5 minutes. Distilled water was slowly injected into the test block within 5 minutes until it was completely submerged. The vacuum was continued for another 5 minutes. After being taken out, the test block was left to stand in the air for 30 minutes to fully saturate it. The saturated test block was transferred to an overflow container filled with distilled water and its apparent mass in the liquid was weighed using the suspension method and recorded as m2. After removing the test block, gently wipe away excess liquid droplets from the surface with a damp towel saturated with liquid, and quickly weigh its mass in air, recording it as m³. Simultaneously, determine the density ρ of distilled water at the test temperature; at 20℃, take a density of 0.9982 g / cm³. 3 Apparent porosity (Pa) is calculated using the following formula: Pa = (m3-m1) / (m3-m2) × 100%, and the average value of 5 test blocks is taken as the final result.

[0069] (2) Bulk density test: Based on the obtained mass m1 of the dry sample block, m2 of the saturated sample block in water, m3 of the saturated sample block in air, and the density ρ of distilled water, the bulk density (Db) is calculated according to the following formula: Db=(m1×ρ) / (m3-m2), with the unit being g / cm³. 3 Five standard test blocks were tested in each batch, and the average value was taken as the final result.

[0070] (3) Compressive strength test: Standard test blocks were cut from the uniform wall thickness of the fired product in each batch. The test blocks were cubes with sides of 40mm × 40mm × 40mm. The six sides of the test blocks were required to be flat and smooth, with a parallelism error of no more than 0.02mm and a perpendicularity error between adjacent sides of no more than 0.05mm. Five test blocks were randomly selected from each batch for testing. A universal testing machine was used for loading. The test block was placed at the center of the upper and lower pressure plates of the testing machine. The loading rate was controlled at 0.5mm / min and the load was uniformly applied until the test block failed. The maximum load F at failure was recorded. The compressive strength was calculated according to the formula σ = F / A, where A is the actual area of ​​the pressure surface of the test block. The average value of the five test blocks was taken as the final result.

[0071] The results are shown in Table 1 below:

[0072] Table 1

[0073]

[0074] According to the performance test results in Table 1, the apparent porosity (9.2%-12.8%) of Examples 1-3 are all within a relatively ideal range, and the bulk density (2.16-2.32 g / cm³) is within a relatively ideal range. 3 The compressive strength (92-100 MPa) showed a good balance. Comparative Example 1, due to the absence of grapefruit peel powder, had an excessively low apparent porosity (6.1%). Although its density and strength (118 MPa) were high, its air permeability was insufficient. Comparative Example 2, after replacing grapefruit peel powder with coconut shell powder, exhibited poor pore structure uniformity; its strength (115 MPa) remained high, but its porosity was low. Comparative Examples 3-4, after replacing yttrium oxide or both yttrium oxide and titanium dioxide respectively, showed a weakened stabilizing effect and reduced sintering activity of tetragonal zirconium oxide, resulting in a lower density (2.52-2.68 g / cm³). 3 While the strength (106-111 MPa) remains relatively high, the porosity (7.6%-8.7%) is still low. Comparative Example 5, although achieving a higher apparent porosity (13.4%) due to sintering in a fully oxidizing atmosphere, suffers a significant decrease in strength to 85 MPa, lacking the optimized grain boundary bonding under a weakly reducing atmosphere. The advantage of this embodiment lies in the synergistic construction of uniform interconnected channels using grapefruit peel powder and rice husk ash, the phase transformation toughening achieved by yttrium oxide stabilizing zirconium dioxide, and the densification sintering promoted by titanium oxide. This results in an optimized balance between porosity (9.2%-12.8%) and permeability while maintaining high strength (92-100 MPa).

[0075] Experiment 2: Wine Aging Test

[0076] High-quality Maotai-flavor or strong-flavor new liquors of the same batch and alcohol content (53% vol) were selected as test samples. The samples were injected into three containers per group and sealed for storage in a constant temperature and humidity environment of 20±2℃ and 60%±5%. Samples were taken for testing at 30, 60, 90, and 180 days of storage. For each time point, three containers from each group were tested in parallel, and the results were averaged. The aging rate was assessed using gas chromatography-mass spectrometry (GC-MS) to determine changes in the content of characteristic flavor compounds such as esters, alcohols, and acids, including changes in major components such as ethyl acetate, isoamyl alcohol, and acetic acid. Initially, the samples contained 1.65 g / L of ethyl acetate, 0.95 g / L of isoamyl alcohol, and 0.7 g / L of acetic acid.

[0077] The results are shown in Tables 2 and 3 below:

[0078] Table 2

[0079]

[0080] Table 3

[0081]

[0082] As can be seen from the aging data in Tables 2 and 3, the content of ethyl acetate, representing pleasant aromas, continuously increased with storage time in Examples 1–3 (reaching 2.49–2.57 g / L after 180 days), while the content of isoamyl alcohol, representing spicy off-flavors, steadily decreased (down to 0.66–0.71 g / L after 180 days). The content of acetic acid, a reactant, also showed a decreasing trend (0.48–0.54 g / L after 180 days). Overall, the wine exhibits typical characteristics of maturing towards a smoother and more harmonious flavor profile. The aging characteristics were as follows: Comparative Examples 1–4 showed a slow increase in ethyl acetate (2.04–2.18 g / L at 180 days) and a limited decrease in isoamyl alcohol (maintained at 0.75–0.77 g / L at 180 days), indicating weaker aging kinetics. Although Comparative Example 5 had a higher apparent porosity, resulting in better aging than Comparative Examples 1–4 (ethyl acetate 2.39 g / L and isoamyl alcohol 0.72 g / L at 180 days), it was still significantly lower than the levels of the Example Group. This difference stemmed from the addition of grapefruit peel powder during the modification stage in the Examples, which constructed micro-nano interconnected channels in situ after firing and combined with multi-stage atmosphere firing, resulting in an "open-closed" dual-pore structure in the body, providing an efficient microenvironment for micro-oxidation and esterification reactions of the wine. In contrast, Comparative Examples 1–4 lacked key pore-forming agents or structural stabilizers, leading to insufficient pore development or insufficient mechanical stability. Comparative Example 5, lacking a weak reduction process stage, had limited aging promotion efficiency. The embodiments achieve a more efficient, stable, and repeatable promotion of the wine aging process by precisely controlling the microstructure and surface chemical activity of the embryo.

Claims

1. A method for preparing purple clay products that promote the aging of wine, characterized in that, Includes the following steps: S1. Raw material processing: After the purple clay ore has been exposed to the open air and weathered for more than 3 months, auxiliary materials are added for crushing, wet absorption to remove iron, and ultrasonic treatment. S2. First vacuum plowing and aging: The ultrasonically treated material is crushed through a 40-60 mesh sieve, ball-milled, sieved, filtered, vacuum plowed and aged for 7-15 days. S3. Modification, Second Vacuuming, and Aging of Purple Clay Slurry: 1-3% zeolite powder, 0.2-0.5% plant fiber reinforcing agent, 0.5-1% barium carbonate, and 0.2-0.5% rice husk ash (by mass percentage) are pre-dry mixed evenly and then sprinkled into the purple clay slurry. The stirring speed is controlled at 80-120 rpm. After stirring for 20-30 minutes, a second vacuum kneading is carried out with a vacuum degree of 700-740 mmHg. Then, the mixture is sealed and aged for 15-30 days. S4. Shaping: Add shaping aids to the purple clay slurry after the second aging, and use vacuum casting process to make the blank; S5. Drying: The shaped wet blank is dried in two stages under controlled temperature and humidity until the moisture content is below 3%; S6. Multi-stage firing: First, pre-firing is performed with a first target temperature of 800℃±10℃. The heating rate is 2℃ / min from room temperature to 300℃, 3℃ / min from 300℃ to 600℃, and 2℃ / min from 600℃ to the first target temperature. After reaching the first target temperature, the temperature is held for 60 minutes. After pre-firing is completed and cooled to room temperature, a second firing is performed with a second target temperature of 1130℃±20℃. The heating rate is 3℃ / min from room temperature to 600℃, 4℃ / min from 600℃ to 950℃, and 2℃ / min from 950℃ to the second target temperature. After reaching the second target temperature, the temperature is held for 90 minutes. The plant fiber enhancer in step S3 is grapefruit peel powder; The step S6, which involves holding the kiln at the second target temperature for 90 minutes after the second firing, includes: using an oxidizing atmosphere for the first 30 minutes of the holding period, with the kiln pressure adjusted to -5 to -10 Pa, and switching to a weak reducing atmosphere for the next 60 minutes, with the kiln pressure adjusted to 5-10 Pa.

2. The method for preparing a Zisha (purple clay) product to promote the aging of wine according to claim 1, characterized in that, Step S1, which involves adding auxiliary materials for crushing, wet adsorption iron removal, and ultrasonic treatment, includes: crushing 95-100 parts of purple clay ore, 1-5 parts of pyrophyllite, 1-2 parts of sodium bentonite, and 0.3-0.5 parts of humic acid; then removing iron using wet adsorption to control the slurry specific gravity below 1.7; followed by magnetic separation using a permanent magnet flat plate magnetic separator, and simultaneous ultrasonic treatment at a frequency of 20-40kHz and a power density of 0.3-0.5W / cm³. 3 .

3. The method for preparing a Zisha (purple clay) product to promote the aging of wine according to claim 1, characterized in that, The ball milling, sieving, filter pressing, vacuum slurry preparation and aging process in step S2 includes: ball milling the material at a ratio of material:water:ball = 1:0.8:1.5 for 12-24 hours until the fineness reaches 250 mesh; passing the ball-milled slurry through a 200-mesh vibrating screen, and then through 2-3 magnetic separations before being sent to a filter press to press into mud cakes with a moisture content of 21%; the mud cakes undergo a first vacuum slurry preparation, with the vacuum degree controlled at 700-740 mmHg, and then are sealed for the first aging for 7-15 days.

4. The method for preparing a purple clay product to promote the aging of wine according to claim 1, characterized in that, The step S4, which involves adding molding aids and using a vacuum casting process to form the blank, includes adding a stabilizer (0.3-0.5% of the total mass of the purple clay slurry), a sintering aid (0.5-0.8%), a toughening agent (0.3-0.5%), polyethylene glycol (0.5-1.0%), and silica (1.5%). After mixing, the mixture is ball-milled for 2-4 hours at a speed of 30-40 rpm. The molding process uses vacuum casting. Water is added to the ball-milled purple clay to control the moisture content to 2%. Add 8%-32% of the clay and 0.2%-0.3% sodium silicate as a diluent. Stir at 60-80 rpm to adjust the fluidity. Pour the clay slurry into a plaster mold and place it on a vacuum vibration table for slurrying. The vacuum degree is -0.08MPa and the vibration frequency is 50Hz for 3-5 minutes. After slurrying, let it stand for 30-40 minutes. When the thickness of the clay body reaches 4-6mm, pour out the excess clay slurry and continue to cure for 2-3 hours before demolding. The stabilizer is yttrium oxide, the sintering aid is titanium oxide, and the toughening agent is zirconium dioxide.

5. The method for preparing a Zisha (purple clay) product to promote the aging of wine according to claim 1, characterized in that, The two-stage temperature and humidity controlled drying process in step S5 includes: the first stage drying temperature is controlled at 30℃±2℃ and humidity at 70%±5%, lasting for 24 hours; the second stage drying temperature is controlled at 38℃±2℃ and humidity at 60%±5%, lasting for 36 hours.

6. A purple clay product for promoting the aging of wine, characterized in that, It is prepared by the method for preparing Zisha products that promote the aging of wine as described in any one of claims 1-5.

7. The application of a purple clay product for promoting the aging of wine as described in claim 6 in alcoholic beverages.

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