Wood ash black glaze and preparation method thereof
By using a ternary synergistic system of rare earth minerals, lithium-containing minerals, and plant ash, the problems of high energy consumption and toxic heavy metals in black glaze have been solved, and a highly saturated, low-temperature fired plant ash black glaze has been prepared, which has unique artistic effects and excellent antibacterial properties.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- NORTHWEST NORMAL UNIVERSITY
- Filing Date
- 2026-04-18
- Publication Date
- 2026-05-29
AI Technical Summary
Existing black glazes suffer from high firing temperatures, high energy consumption, insufficient color saturation, and contain toxic heavy metals, making it difficult to meet the requirements of modern ceramic art for color expression and antibacterial properties.
A ternary synergistic system was constructed using rare earth minerals, lithium-containing minerals, and plant ash. Through calcination activation of composite powder, double-layer glazing, and staged reduction firing, a plant ash black glaze with high color saturation and low firing temperature was prepared.
It achieves a unique artistic effect with blue-purple kiln-transformed flow patterns on a dark green base, creating rich layers. It also boasts excellent environmental protection and antibacterial properties, reduces firing energy consumption, and improves the hardness and thermal stability of the glaze.
Smart Images
Figure CN122102515A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of glaze preparation technology, specifically to a plant ash black glaze and its preparation method. Background Technology
[0002] Black glaze is an important component of traditional Chinese high-temperature colored glazes, its color primarily relying on the color development of iron oxides in the glaze under a reducing atmosphere. Existing black glazes mostly employ a mixture of traditional clay minerals and wood ash, resulting in a relatively simple glaze effect and lacking the rich kiln-transformation effects. Traditional wood ash black glazes are typically fired at temperatures above 1250℃, consuming a large amount of energy, and the glaze's color saturation is insufficient, failing to meet the demands of modern ceramic art for color expression. Furthermore, some traditional glazes, in order to lower the firing temperature or improve the glaze's gloss, often add chemical raw materials containing toxic heavy metals such as lead and cadmium, posing hazards not only to production personnel and the environment but also potentially releasing heavy metal ions during use, creating safety risks. Simultaneously, ceramic products are prone to bacterial growth, especially in tableware and bathroom applications, placing higher demands on antibacterial properties.
[0003] Therefore, how to develop a plant ash black glaze with high color saturation, low firing temperature, unique artistic effect, and environmental protection and antibacterial properties is a technical problem that urgently needs to be solved in this field. Summary of the Invention
[0004] To address the aforementioned problems, this invention provides a plant ash black glaze with high color saturation, low firing temperature, unique artistic effect, and good environmental protection and antibacterial properties, as well as its preparation method.
[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows: This invention provides a plant ash black glaze, prepared from the following raw materials in parts by weight: 50-60 parts silicon dioxide, 9-12 parts aluminum oxide, 7-10 parts calcium oxide, 1-3 parts magnesium oxide, 4-6 parts ferric oxide, 2-6 parts potassium oxide, 3-8 parts rare earth mineral (fluorocarbon cerium ore), 5-10 parts lithium-containing mineral (lepidolite), 12-15 parts quartz, 2-4 parts potassium feldspar, 5-8 parts plagioclase, 7-10 parts calcite, 30-35 parts dolomite, 20-25 parts illite, 6-9 parts illite-montmorillonite mixed layer, 5-8 parts chlorite, 3-5 parts kaolinite, and 10-20 parts plant ash.
[0006] Further, it is prepared from the following raw materials in parts by weight: 55 parts silicon dioxide, 10 parts aluminum oxide, 8 parts calcium oxide, 2 parts magnesium oxide, 5 parts ferric oxide, 4 parts potassium oxide, 5 parts rare earth mineral (bastnaesite), 8 parts lithium-containing mineral (lepidolite), 14 parts quartz, 3 parts potassium feldspar, 6 parts plagioclase, 8 parts calcite, 32 parts dolomite, 22 parts illite, 8 parts illite-montmorillonite mixed layer, 6 parts chlorite, 4 parts kaolinite, and 15 parts wood ash.
[0007] The components of the above raw materials play the following roles in the glaze: Silica and quartz provide the framework for the glaze layer, forming a glass network structure.
[0008] Alumina, illite, illite-montmorillonite mixed layer, chlorite, kaolinite and other clay minerals: adjust the high-temperature viscosity of the glaze, and enhance the hardness and chemical stability of the glaze surface.
[0009] Calcium oxide, calcite, and dolomite: provide CaO and MgO, which act as fluxes and affect the texture of the glaze.
[0010] Magnesium oxide and chlorite: provide magnesium, participate in spinel formation, and enrich the glaze color.
[0011] Ferric oxide: the main colorant, which is converted to Fe under a reducing atmosphere. 2+ This establishes a dark green base.
[0012] Potassium oxide, potassium feldspar, and plagioclase: provide alkali metal oxides such as K2O and Na2O, which lower the melting temperature of the glaze.
[0013] Rare earth minerals (bastnaesite): provide rare earth elements (Ce, La, etc.), significantly improve the color saturation of the glaze, and give the glaze a blue-purple kiln transformation effect. This may be due to the fact that rare earth ions and iron ions form a composite color-producing structure, which broadens the light absorption range. At the same time, rare earth elements have broad-spectrum antibacterial properties, which can give the glaze excellent antibacterial performance.
[0014] Lithium-containing minerals (lepidolite): provide lithium ions, have a strong fluxing effect, can significantly reduce the melting temperature of glaze, reduce firing energy consumption, and at the same time adjust the thermal expansion coefficient of the glaze layer to improve the glaze surface quality.
[0015] Wood ash provides various trace elements and alkali metal oxides, promotes the uniform dispersion of rare earth elements, enhances the rustic texture of the glaze, enriches the color layers of the glaze, and works synergistically with rare earth elements and lithium to achieve unique artistic effects. Wood ash itself is a natural and renewable resource, non-toxic and harmless.
[0016] This invention also provides a method for preparing plant ash black glaze, specifically including the following steps: S1: Fluorocarbon cerium ore and lepidolite are mixed, roasted, cooled, ground and sieved to obtain activated composite powder; S2: Mix the remaining raw materials with the activated composite powder, add water, ball mill, and then sieve to obtain glaze slurry A; S3: Add water to the wood ash separately, ball mill, and sieve to obtain glaze slurry B; S4: First, apply glaze slurry B to the surface of the ceramic body, and after it dries, apply glaze slurry A on top of it to form a double-layer glaze structure; S5: Place the glazed body in a kiln and fire it.
[0017] Furthermore, in step S1, the calcination temperature is 700-800℃, the calcination time is 1-2 hours, and the sieve size is 300 mesh.
[0018] Furthermore, in step S2, the ball milling time is 8-10 hours, and the sieve size is 200 mesh; the specific gravity of glaze slurry A is 1.65 ± 0.05 g / cm³. 3 .
[0019] Furthermore, in step S3, the ball milling time is 4-6 hours, and the sieve size is 300 mesh; the specific gravity of the glaze slurry B is 1.35 ± 0.05 g / cm³. 3 .
[0020] Furthermore, in step S4, the thickness of glaze slurry B is 0.1-0.2 mm, and the thickness of glaze slurry A is 0.3-0.5 mm.
[0021] Furthermore, in step S5, the firing process specifically includes the following steps: S51: Drying stage: Place the glazed body into the kiln and let the temperature rise evenly to 350-380℃ over 2-3 hours. S52: Oxidizing Flame Stage: Under an oxidizing atmosphere, the temperature is uniformly raised to 900-980℃ over 2.5-3.5 hours; S53: Strong reducing flame stage: Under a strong reducing atmosphere (CO concentration 5 vol%), the temperature is uniformly raised to 1200-1220℃ over 1.5-2.5 hours; S54: Weak reducing flame stage: Under a weak reducing atmosphere (CO concentration 2 vol%), the temperature is uniformly increased to 1220-1250℃ over 5.5-7 hours; S55: Rapid cooling stage: Open the kiln door 8-12 cm to rapidly cool the temperature to 1150-1180℃; S56: Slow cooling stage: Seal the kiln door, air outlet and air inlet to reduce the temperature to room temperature and allow the glaze to undergo secondary crystallization (the secondary microcrystal precipitation makes the glaze hardness reach 6-7 on the Mohs scale, improves thermal stability, and at the same time gives the glaze a warm and jade-like texture).
[0022] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention introduces rare earth minerals and lithium-containing minerals to construct a ternary synergistic system of "rare earth-lithium-wood ash," significantly improving the color saturation and artistic effect of the glaze compared to traditional clay minerals and wood ash. Experiments show that the wood ash black glaze prepared by this invention has high color saturation (C* value reaches 9.0), more than double that of traditional formulas. The glaze exhibits a unique artistic effect with a dark green base and blue-purple kiln-transformation flow patterns, creating a rich, layered, and elegant appearance. Simultaneously, the introduction of lithium-containing minerals lowers the complete melting temperature of the glaze to 1220-1240℃, 80-100℃ lower than traditional formulas, reducing firing energy consumption by more than 15%. Furthermore, the glaze achieves a Mohs hardness of 6-7, exhibiting good thermal stability and balancing artistry and practicality. The synergistic effect of rare earth minerals, lithium-containing minerals, and wood ash results in a color enhancement greater than the sum of their individual effects, achieving a significant synergistic effect of 1+1+1>3.
[0023] Furthermore, this invention also possesses excellent environmental friendliness and antibacterial properties: the raw materials used are all natural minerals and wood ash, free of toxic heavy metals such as lead and cadmium, and no harmful gases are released during the firing process, meeting green environmental protection requirements. Simultaneously, the introduction of rare earth elements endows the glaze with broad-spectrum antibacterial properties. Testing in Example 2 showed that it effectively inhibits Escherichia coli (E. coli). Escherichia coli ) and Staphylococcus aureus ( Staphylococcus aureus The antibacterial rates of the two products reached 98.5% and 96.2% respectively, demonstrating highly efficient and long-lasting antibacterial effects. They are suitable for ceramic products with high hygiene requirements, such as tableware and bathroom fixtures. Attached Figure Description
[0024] Figure 1 This is a photo of the plant ash black glaze tea set from Example 1; Figure 2 This is a photo of the plant ash black glaze tea set from Example 2; Figure 3 This is a photo of the plant ash black glaze tea set from Example 3. Detailed Implementation
[0025] To make the objectives and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are only for explaining the invention and are not intended to limit the invention.
[0026] Unless otherwise specified, the instruments, reagents, and materials used in the following embodiments are all conventional instruments, reagents, and materials already available in the prior art and can be obtained through legitimate commercial channels. Unless otherwise specified, the experimental methods and detection methods used in the following embodiments are all conventional experimental methods and detection methods already available in the prior art.
[0027] Example 1 This embodiment provides a plant ash black glaze, which is prepared from the following raw materials in parts by weight: 50 parts silicon dioxide, 9 parts aluminum oxide, 7 parts calcium oxide, 1 part magnesium oxide, 4 parts ferric oxide, 2 parts potassium oxide, 3 parts bastnaesite, 5 parts lepidolite, 12 parts quartz, 2 parts potassium feldspar, 5 parts plagioclase, 7 parts calcite, 30 parts dolomite, 20 parts illite, 6 parts illite-montmorillonite mixed layer, 5 parts chlorite, 3 parts kaolinite, and 10 parts plant ash.
[0028] The preparation method of this plant ash black glaze specifically includes the following steps: S1: Mix bastnaesite with lepidolite, calcine at 700℃ for 2 hours, cool and grind through a 300-mesh sieve to obtain activated composite powder; S2: Mix the remaining raw materials with the activated composite powder, add water and ball mill for 8 hours, then pass through a 200-mesh sieve to obtain glaze slurry A with a specific gravity of 1.65±0.05 g / cm³. 3 ; S3: The wood ash was separately ball-milled with water for 4 hours, then passed through a 300-mesh sieve to obtain glaze slurry B with a specific gravity of 1.35 ± 0.05 g / cm³. 3 ; S4: First, apply glaze slurry B to the surface of the ceramic body with a thickness of 0.1mm. After drying, apply glaze slurry A on top with a thickness of 0.3mm to form a double-layer glaze structure. S5: The glazed body is placed in a kiln for firing. The firing process specifically includes the following steps: S51: Drying stage: Place the glazed body into the kiln and let the temperature rise evenly to 380℃ over 3 hours. S52: Oxidizing Flame Stage: Under an oxidizing atmosphere, the temperature is uniformly increased to 980℃ over 3.5 hours; S53: Strong reducing flame stage: Under a strong reducing atmosphere, the temperature is uniformly raised to 1220℃ over 2.5 hours; S54: Weak reducing flame stage: Under a weak reducing atmosphere, the temperature is uniformly raised to 1250℃ over 7 hours; S55: Rapid cooling stage: Open the kiln door 12 cm to rapidly cool the temperature to 1180℃; S56: Slow Cooling Stage: The kiln door, air outlet, and air inlet are completely sealed to allow the temperature to drop to room temperature, enabling secondary crystallization of the glaze. The glaze is dark green with a small amount of bluish-purple flow lines, exhibiting rich layers and a soft luster. Figure 1 .
[0029] Example 2 This embodiment provides a plant ash black glaze, which is prepared from the following raw materials in parts by weight: 55 parts silicon dioxide, 10 parts aluminum oxide, 8 parts calcium oxide, 2 parts magnesium oxide, 5 parts ferric oxide, 4 parts potassium oxide, 5 parts bastnaesite, 8 parts lepidolite, 14 parts quartz, 3 parts potassium feldspar, 6 parts plagioclase, 8 parts calcite, 32 parts dolomite, 22 parts illite, 8 parts illite-montmorillonite mixed layer, 6 parts chlorite, 4 parts kaolinite, and 15 parts plant ash.
[0030] The preparation method of this plant ash black glaze specifically includes the following steps: S1: Mix bastnaesite with lepidolite, calcine at 750℃ for 1.5h, cool and grind through a 300-mesh sieve to obtain activated composite powder; S2: Mix the remaining raw materials with the activated composite powder, add water and ball mill for 9 hours, then pass through a 200-mesh sieve to obtain glaze slurry A with a specific gravity of 1.65±0.05 g / cm³. 3 ; S3: The wood ash was separately ball-milled with water for 5 hours, then passed through a 300-mesh sieve to obtain glaze slurry B with a specific gravity of 1.35 ± 0.05 g / cm³. 3 ; S4: First, apply glaze slurry B to the surface of the ceramic body with a thickness of 0.15mm. After drying, apply glaze slurry A on top with a thickness of 0.4mm to form a double-layer glaze structure. S5: The glazed body is placed in a kiln for firing. The firing process specifically includes the following steps: S51: Drying stage: Place the glazed body into the kiln and allow the temperature to rise evenly to 360℃ over 2.5 hours. S52: Oxidizing Flame Stage: Under an oxidizing atmosphere, the temperature is uniformly raised to 950℃ over 3 hours; S53: Strong reducing flame stage: Under a strong reducing atmosphere, the temperature is uniformly raised to 1210℃ over 2 hours; S54: Weak reducing flame stage: Under a weak reducing atmosphere, the temperature is uniformly raised to 1240℃ over 6 hours; S55: Rapid cooling stage: Open the kiln door 10 cm to rapidly cool the temperature to 1160℃; S56: Slow Cooling Stage: The kiln door, air outlet, and air inlet are completely sealed to allow the temperature to drop to room temperature, enabling secondary crystallization of the glaze. The glaze is a deep dark green with distinct blue-purple kiln-transformation flow patterns, exhibiting rich color and layered texture, possessing a rustic and elegant jade-like quality. Figure 2 .
[0031] Example 3 This embodiment provides a plant ash black glaze, which is prepared from the following raw materials in parts by weight: 60 parts silicon dioxide, 12 parts aluminum oxide, 10 parts calcium oxide, 3 parts magnesium oxide, 6 parts ferric oxide, 6 parts potassium oxide, 8 parts bastnaesite, 10 parts lepidolite, 15 parts quartz, 4 parts potassium feldspar, 8 parts plagioclase, 10 parts calcite, 35 parts dolomite, 25 parts illite, 9 parts illite-montmorillonite mixed layer, 8 parts chlorite, 5 parts kaolinite, and 20 parts plant ash.
[0032] The preparation method of this plant ash black glaze specifically includes the following steps: S1: Mix bastnaesite with lepidolite, calcine at 800℃ for 1 hour, cool and grind through a 300-mesh sieve to obtain activated composite powder; S2: Mix the remaining raw materials with the activated composite powder, add water and ball mill for 10 hours, then pass through a 200-mesh sieve to obtain glaze slurry A with a specific gravity of 1.65±0.05 g / cm³. 3 ; S3: The wood ash was separately ball-milled with water for 6 hours, then passed through a 300-mesh sieve to obtain glaze slurry B with a specific gravity of 1.35 ± 0.05 g / cm³. 3 ; S4: First, apply glaze slurry B to the surface of the ceramic body with a thickness of 0.2mm. After drying, apply glaze slurry A on top with a thickness of 0.5mm to form a double-layer glaze structure. S5: The glazed body is placed in a kiln for firing. The firing process specifically includes the following steps: S51: Drying stage: Place the glazed body into the kiln and let the temperature rise evenly to 350℃ over 2 hours. S52: Oxidizing Flame Stage: Under an oxidizing atmosphere, the temperature is uniformly increased to 900℃ over 2.5 hours; S53: Strong reducing flame stage: Under a strong reducing atmosphere, the temperature is uniformly raised to 1200℃ over 1.5 hours; S54: Weak reducing flame stage: Under a weak reducing atmosphere, the temperature is uniformly increased to 1220℃ over 5.5 hours; S55: Rapid cooling stage: Open the kiln door 8 cm to rapidly cool the temperature to 1150℃; S56: Slow Cooling Stage: The kiln door, air outlet, and air inlet are completely sealed to allow the temperature to drop to room temperature, enabling secondary crystallization of the glaze. The glaze exhibits a dark green to blackish tone with denser blue-purple flow lines, resulting in a deep and heavy overall effect. Figure 3 .
[0033] Comparative Example 1: No rare earth minerals (fluorocarbon cerium ore) The difference from Example 2 is that bastnaesite is replaced with an equal amount of quartz, while the remaining raw material ratios and preparation methods are the same as in Example 2. The glaze is dark green, but the color is lighter, with no obvious kiln-transformation flow patterns and a single layer.
[0034] Comparative Example 2: No lithium-containing minerals (lepidolite) The difference from Example 2 is that lepidolite is replaced with an equal amount of quartz, while the remaining raw material ratios and preparation methods are the same as in Example 2. The glaze is grayish-green with poor luster and a slightly rough surface.
[0035] Comparative Example 3: No wood ash The difference from Example 2 is that the wood ash is replaced with an equal amount of quartz stone, while the remaining raw material ratios and preparation methods are the same as in Example 2. The glaze is yellowish-brown, without any dark green hue, and has a matte finish with fine cracks.
[0036] Comparative Example 4: Unactivated rare earth-lithium minerals The difference from Example 2 is that step S1 is omitted in the preparation method, and step S2 directly involves mixing all raw materials and ball milling. The proportions of the remaining raw materials and the preparation method are the same as in Example 2. The glaze is dark green, but the flow lines are not obvious, and the color uniformity is poor.
[0037] Comparative Example 5: One-Step Glazing The difference from Example 2 is that the glazing method in step S4 is changed to a traditional one-step glazing (glazing slurry A and glaze slurry B are mixed and then applied in one step), while the remaining raw material ratios and preparation methods are the same as in Example 2. The glaze surface is dark green, with blurred flow lines and weak layering.
[0038] Comparative Example 6 contains only bastnaesite. The difference from Example 2 is that lepidolite and wood ash are removed, and the amount of quartz used is increased. The remaining raw material ratios and preparation methods are the same as in Example 2. The glaze is a light dark green, with a pale color and no layering.
[0039] Comparative Example 7 contains only lepidolite The difference from Example 2 is that bastnaesite and wood ash are removed, and the amount of quartz used is increased. The remaining raw material ratios and preparation methods are the same as in Example 2. The glaze is grayish-green, uneven, and contains localized bubbles.
[0040] Comparative Example 8: Contains only wood ash The difference from Example 2 is that bastnaesite and lepidolite are removed, and the amount of quartz used is increased. The remaining raw material ratios and preparation methods are the same as in Example 2. The glaze is dark green with a yellowish tint and has a small amount of flow lines, but they are not obvious.
[0041] Comparative Example 9 (Blank) The difference from Example 2 is that bastnaesite, lepidolite, and wood ash are removed, and the amount of quartz used is increased. The remaining raw material ratios and preparation methods are the same as in Example 2. The glaze is yellowish-brown, matte, rough, and has obvious cracks.
[0042] Experimental Example 1 1. Performance Testing Methods (1) Evaluation of glaze color effect The color parameters (L, a, b) of the glaze were measured using a CS-820 spectrophotometer and calculated according to the formula. Calculate the color saturation C value. The higher the C value, the more vivid and saturated the color. Measure 3 points for each sample and take the average value.
[0043] (2) Determination of complete melting temperature The melting process of the glaze was observed using a high-temperature microscope, and the temperature at which the glaze completely melted into a hemispherical shape was recorded as the complete melting temperature.
[0044] (3) Glaze hardness test An HVS-1000 digital display microhardness tester was used with a load of 100g and a holding time of 10s to determine the Vickers hardness of the glaze surface, which was then converted to Mohs hardness. Five points were measured for each sample group, and the average value was taken.
[0045] (4) Thermal stability test Place the glaze sample in a 200℃ oven for 30 minutes, then immediately remove it and immerse it in 20℃ cold water. Repeat this process three times and observe whether cracks appear on the glaze surface.
[0046] (5) Antibacterial performance test Referring to GB / T 21866-2008 "Determination of Antibacterial Properties and Antibacterial Effects of Antibacterial Coatings (Films)", the film application method was used to test the antibacterial activity of the glaze against Escherichia coli (E. coli). Escherichia coli ) and Staphylococcus aureus ( Staphylococcus aureus The antibacterial rate was measured. The sample size was 50mm × 50mm, and the bacterial concentration was approximately 5 × 10⁻⁶. 5 The antibacterial rate was calculated after 24 hours of contact culture with CFU / mL. Each sample group was tested three times, and the average value was taken.
[0047] 2. Test Results (1) Glaze color effect Table 1 Evaluation of Glaze Coloration Effect
[0048] (2) Test results of glaze melting characteristics and physical properties of glaze surface Table 2. Test results of glaze melting characteristics and glaze surface physical properties
[0049] (3) Antibacterial performance test results Table 3 Antibacterial performance test results
[0050] 3. Results Analysis As shown in Table 1, the C* values of Examples 1-3 are significantly higher than those of Comparative Examples 1-3. This indicates that rare earth minerals, lithium-containing minerals, and wood ash are all essential for achieving a high-saturation glaze, and the absence of any one of them will lead to a significant decrease in color rendering. Combined with the description of the glaze's artistic effect, Comparative Example 1 lacks a blue-purple hue when rare earth minerals are absent, Comparative Example 2 has poor glaze gloss when lithium is absent, and Comparative Example 3 has a yellowish hue when wood ash is absent, further confirming the unique role of the three. Meanwhile, Table 2 shows that the complete melting temperatures of Comparative Examples 1-3 are all higher than those of Examples 1-3, and the thermal stability of the glaze deteriorates (slight cracking occurs) when wood ash is absent, further demonstrating the indispensability of the three.
[0051] On the other hand, the C* values of Examples 1-3 are significantly higher than those of Comparative Example 4, and the glaze flow lines are not obvious, indicating that the rare earth-lithium mineral pre-activation step (step S1) can effectively release active ions and promote color development and phase separation. The C* value of Comparative Example 5 is also lower than that of Examples 1-3, and the glaze layering is weak, indicating that the gradient glazing process (step S4) helps to form a compositional gradient, enhancing the phase separation effect and color layering. Both demonstrate the uniqueness and necessity of the process steps of the present invention.
[0052] In addition, using the blank group (Comparative Example 9) as a benchmark, the C* enhancement value of each group was calculated. The results showed that the enhancement values of Examples 1-3 were significantly higher than the sum of the enhancement values of Comparative Examples 6-8. This indicates that the color enhancement effect produced by the combination of rare earth minerals, lithium-containing minerals and plant ash is greater than the sum of their individual effects, proving that there is a significant synergistic effect among the three (1+1+1>3).
[0053] As shown in Table 2, the Mohs hardness of the glazes in Examples 1-3 is 6.5-7.0, significantly higher than that of the comparative examples (4.5-6.0), indicating that the glazes prepared by the glaze formulation and process of this invention are denser and harder. Regarding thermal stability, no cracks were observed in any of the examples, while obvious cracks appeared in the blank group. Only the lithium group and the group without plant ash showed slight cracks, indicating that rare earth elements, lithium, and plant ash synergistically improved the thermal expansion matching of the glaze layer.
[0054] As shown in Table 3, Examples 1-3 all achieved antibacterial rates of over 90% against *Escherichia coli* and *Staphylococcus aureus*, with Example 2 achieving antibacterial rates of 98.5% and 96.2%, respectively, demonstrating excellent broad-spectrum antibacterial performance. In contrast, Comparative Example 1, without rare earth elements, showed a significantly lower antibacterial rate (<50%), indicating that rare earth elements are key to imparting antibacterial properties to the glaze. Comparative Example 7, containing only lithium, and Comparative Example 8, containing only wood ash, also had low antibacterial rates (20-30%), while Comparative Example 6, containing only rare earth elements, achieved an antibacterial rate of over 70%, further confirming the dominant role of rare earth elements. Furthermore, the antibacterial rates of Examples 1-3 were superior to Comparative Example 6 (rare earth only), suggesting that the synergistic effect of rare earth elements with lithium and wood ash may have promoted the uniform distribution and activity retention of rare earth elements in the glaze, thereby enhancing the antibacterial effect. The antibacterial rates of Comparative Example 4 (unactivated) and Comparative Example 5 (one-step glazing) were both lower than those of Examples 1-3, indicating that the activation process and gradient glazing of the present invention help to exert the antibacterial function of rare earth elements.
[0055] In summary, this invention introduces rare earth minerals and lithium-containing minerals to construct a ternary synergistic system of "rare earth minerals-lithium-wood ash," and, combined with processes such as rare earth-lithium mineral activation, gradient glazing, and staged reduction firing, successfully prepares a wood ash black glaze with high color saturation, low firing temperature, and excellent glaze performance. The glaze exhibits a unique artistic effect with blue-purple kiln-transformation patterns on a dark green base, rich in layers, and simple and elegant. Furthermore, the glaze of this invention also possesses excellent environmental protection and antibacterial properties: the raw materials are all natural minerals and wood ash, free of toxic heavy metals such as lead and cadmium; the introduction of rare earth elements enables the glaze to achieve antibacterial rates of 98.5% and 96.2% against Escherichia coli and Staphylococcus aureus, respectively, combining artistic beauty with hygienic function.
[0056] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.
Claims
1. A plant-gray ash-black glaze, characterized in that: It is prepared from the following raw materials in parts by weight: 50-60 parts silicon dioxide, 9-12 parts aluminum oxide, 7-10 parts calcium oxide, 1-3 parts magnesium oxide, 4-6 parts ferric oxide, 2-6 parts potassium oxide, 3-8 parts bastnaesite, 5-10 parts lepidolite, 12-15 parts quartz, 2-4 parts potassium feldspar, 5-8 parts plagioclase, 7-10 parts calcite, 30-35 parts dolomite, 20-25 parts illite, 6-9 parts illite-saturated mixed layer, 5-8 parts chlorite, 3-5 parts kaolinite, and 10-20 parts wood ash.
2. The plant ash black glaze according to claim 1, characterized in that: It is prepared from the following raw materials in parts by weight: 55 parts silicon dioxide, 10 parts aluminum oxide, 8 parts calcium oxide, 2 parts magnesium oxide, 5 parts ferric oxide, 4 parts potassium oxide, 5 parts bastnaesite, 8 parts lepidolite, 14 parts quartz, 3 parts potassium feldspar, 6 parts plagioclase, 8 parts calcite, 32 parts dolomite, 22 parts illite, 8 parts illite-montmorillonite mixed layer, 6 parts chlorite, 4 parts kaolinite, and 15 parts wood ash.
3. The method for preparing plant ash black glaze as described in any one of claims 1-2, characterized in that: Specifically, the steps include the following: S1: Fluorocarbon cerium ore and lepidolite are mixed, roasted, cooled, ground and sieved to obtain activated composite powder; S2: Mix the remaining raw materials with the activated composite powder, add water, ball mill, and then sieve to obtain glaze slurry A; S3: Add water to the wood ash separately, ball mill, and sieve to obtain glaze slurry B; S4: First, apply glaze slurry B to the surface of the ceramic body, and after it dries, apply glaze slurry A on top of it to form a double-layer glaze structure; S5: Place the glazed body in a kiln and fire it.
4. The preparation method according to claim 3, characterized in that: In step S1, the calcination temperature is 700-800℃, the calcination time is 1-2 hours, and the sieve size is 300 mesh.
5. The preparation method according to claim 3, characterized in that: In step S2, the ball milling time is 8-10 hours, and the sieve size is 200 mesh; the specific gravity of glaze slurry A is 1.65±0.05 g / cm³. 3 .
6. The preparation method according to claim 3, characterized in that: In step S3, the ball milling time is 4-6 hours, and the sieve size is 300 mesh; the specific gravity of glaze slurry B is 1.35±0.05 g / cm³. 3 .
7. The preparation method according to claim 3, characterized in that: In step S4, the thickness of glaze slurry B is 0.1-0.2 mm, and the thickness of glaze slurry A is 0.3-0.5 mm.
8. The preparation method according to claim 3, characterized in that: In step S5, the firing process specifically includes the following steps: S51: Drying stage: Place the glazed body into the kiln and let the temperature rise evenly to 350-380℃ over 2-3 hours. S52: Oxidizing Flame Stage: Under an oxidizing atmosphere, the temperature is uniformly raised to 900-980℃ over 2.5-3.5 hours; S53: Strong reducing flame stage: Under a strong reducing atmosphere, the temperature is uniformly raised to 1200-1220℃ over 1.5-2.5 hours; S54: Weak reducing flame stage: Under a weak reducing atmosphere, the temperature is uniformly raised to 1220-1250℃ over 5.5-7 hours; S55: Rapid cooling stage: Open the kiln door 8-12 cm to rapidly cool the temperature to 1150-1180℃; S56: Slow cooling stage: Seal the kiln door, air outlet, and air inlet to reduce the temperature to room temperature and allow the glaze to crystallize again.