A method for preparing black pottery using a low-temperature strong reduction carbonization process

Abstract

This invention discloses a method for preparing black pottery using a low-temperature strong reduction carbonization process, comprising the following steps: weighing raw materials, adding water, and ball milling to obtain clay; wherein, part of the raw materials are derived from clay; forming the clay into a blank using a slip casting method; after drying, placing the blank into a gas-fired kiln, first sintering it in an oxidizing atmosphere, and then switching to a strong reducing atmosphere at 620℃, with a maximum sintering temperature of 1100-1110℃ and a firing cycle of 4.5 hours; the firing process is divided into six stages. The firing process involves six stages: First stage firing temperature: 50-350℃, firing time: 0.5h; Second stage firing temperature: 350-550℃, firing time: 0.5h; Third stage firing temperature: 550-620℃, firing time: 1h; Fourth stage firing temperature: 620-980℃, firing time: 1h; Fifth stage firing temperature: 980℃ to the maximum sintering temperature, firing time: 1h; Sixth stage firing temperature: holding at the maximum sintering temperature for 0.5h, followed by slow cooling before removal from the kiln to obtain the black pottery. The black pottery of this invention has a uniform and aesthetically pleasing black outer shell, and exhibits high strength and hardness.

Description

Technical Field

[0001] This invention belongs to the field of pottery preparation technology, and specifically relates to a method for preparing black pottery using a low-temperature strong reduction carbonization process. Background Technology

[0002] Black pottery, originating in the Neolithic Age of China, is an ancient Chinese pottery-making technique. It is an unglazed pottery produced through a series of special processes and fired at a relatively low temperature using carbonization. Its characteristics include a black color like lacquer, a mirror-like sheen, a paper-thin texture, and a porcelain-like hardness. Currently, the production of black pottery is widespread, but most manufacturers still face numerous problems in their firing processes, such as insufficient body strength, a lack of true black color, and a black exterior with a gray interior. To better inherit and develop the culture of black pottery, there is an urgent need to improve its manufacturing process.

[0003] Chinese patent application CN201210477480.1 discloses a method for preparing charcoal-inlaid black pottery, which includes a material selection process. This process uses Yellow River sediment and peony charcoal with a particle size of 10-60 μm as raw materials, with a weight ratio of Yellow River sediment to peony charcoal of 1.5-9:1. This method, by adding peony charcoal as a raw material, produces black pottery that is black both inside and out, with a uniform color, high hardness, low porosity, and a water absorption rate between 0.5-10%. The normal spectral emissivity within the 8-15 μm range reaches over 85%. Carbonization is one of the key technologies in black pottery production, giving the pottery a unique black appearance and excellent physicochemical properties. How to balance the carbonization effect and apparent porosity of black pottery through control of raw materials and processes remains a major challenge. Summary of the Invention

[0004] To address the aforementioned problems, this invention provides a method for preparing black pottery using a low-temperature strong reduction carbonization process. The carbonization effect of this invention is better, and the resulting black pottery has stable color.

[0005] The technical solution of the present invention is as follows:

[0006] One objective of this invention is to provide a method for preparing black pottery using a low-temperature strong reduction carbonization process, comprising the following steps:

[0007] S1: Weigh 52-56 parts of silicon dioxide, 20-23 parts of aluminum oxide, 1.2-1.5 parts of potassium oxide, 1.1-1.3 parts of sodium oxide, 0.2-0.4 parts of calcium oxide, 0.2-0.4 parts of magnesium oxide, 1.5-2 parts of titanium oxide, 8-10 parts of iron oxide, and 3-6 parts of manganese oxide, add water and ball mill to obtain mud; some of the raw materials come from clay;

[0008] S2: The clay obtained in step S1 is made into a blank by slip casting;

[0009] S3: After the green body obtained in step S2 is dried, it is placed in a gas-fired kiln. It is first sintered in an oxidizing atmosphere, and then switched to a strong reducing atmosphere when the temperature reaches 620℃. The maximum sintering temperature is 1100-1110℃, and the firing cycle is 4.5 hours. The firing curve of the firing process is divided into six stages: Stage 1: Firing temperature 50-350℃, firing time 0.5 hours; Stage 2: Firing temperature 350-550℃, firing time 0.5 hours; Stage 3: Firing temperature 550-620℃, firing time 1 hour; Stage 4: Firing temperature 620-980℃, firing time 1 hour; Stage 5: Firing temperature 980℃ to the maximum sintering temperature, firing time 1 hour; Stage 6: Holding at the maximum sintering temperature for 0.5 hours, and then slowly cooling after firing to obtain the black pottery.

[0010] Furthermore, in step S1, the particle size D50 of the mud is 7.5-8.5μm, and the mud specific gravity is 1.75-1.80.

[0011] Furthermore, in step S1, during the ball milling process, the ratio of material:ball:water = 1:2:0.3, the rotation speed of the ball mill is 60 r / min, and the ball milling time is 4 h.

[0012] Furthermore, in step S2, the thickness of the obtained blank is 5-8 mm.

[0013] Furthermore, in step S3, at 900℃, the length of the strong reducing flame passing through the observation hole is 15-20cm.

[0014] The second objective of this invention is to provide a black pottery produced by any of the above methods.

[0015] Furthermore, the apparent porosity of the black pottery is ≥30%.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] 1. This invention provides a method for preparing black pottery using a low-temperature strong reduction carburization process. During firing, to prevent cracking caused by the crystal transformation of silica, a slow heating method is used before reaching 620℃. This invention controls the penetration rate and depth of carbon elements by controlling the firing temperature and firing time, and ensures that the apparent porosity of the body is greater than or equal to 30%, achieving an optimal balance between the apparent porosity and carburization effect of the black pottery. At this point, the black pottery possesses good appearance and properties, and the finished product has a uniform and beautiful black outer shell, as well as good strength and hardness. Since the apparent porosity of the semi-finished product is greater than 30% at a sintering temperature of 600-1000℃, and the carburization effect is better at this temperature, this invention uses 620℃ as the transition point for the reducing atmosphere. At around 800℃, the organic matter in the clay decomposes, forming a large amount of highly reactive nascent carbon. This is conducive to the carburizing reaction. Furthermore, driven by the reducing atmosphere of CO and catalyzed by iron oxide, the carburizing reaction proceeds more easily. Even though the firing temperature used in this invention is relatively low, the carburizing effect is still quite good. At 600-1050℃, the apparent porosity stabilizes at around 30%, and the firing time has little impact on the carburizing effect of the product. Therefore, this invention uses a low-temperature, rapid firing method, which achieves the goal of saving energy.

[0018] 2. The black pottery prepared by the present invention using a low-temperature strong reduction carbonization process has good appearance properties, with a uniform and beautiful black outer shell, and high strength and hardness. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of black pottery prepared by a method for preparing black pottery using a low-temperature strong reduction carbonization process provided by the present invention.

[0020] Figure 2 The firing curve is provided by the present invention for a method of preparing black pottery using a low-temperature strong reduction carbonization process. Detailed Implementation

[0021] The following describes a preferred embodiment, with reference to the appendix. Figure 1-2 To further illustrate the present invention, the endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values; for numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, and these numerical ranges should be considered as specifically disclosed herein; the materials, reagents, etc. used in the following embodiments are commercially available unless otherwise specified; the experimental methods in the following embodiments are conventional methods unless otherwise specified.

[0022] Example 1

[0023] This embodiment provides a method for preparing black pottery using a low-temperature strong reduction carbonization process, including the following steps:

[0024] S1: Weigh out 54 parts of silicon dioxide, 21 parts of aluminum oxide, 1.2 parts of potassium oxide, 1.2 parts of sodium oxide, 0.3 parts of calcium oxide, 0.25 parts of magnesium oxide, 1.6 parts of titanium oxide, 8.5 parts of iron oxide, and 4 parts of manganese oxide, add water and ball mill to obtain mud; some of the raw materials are from clay.

[0025] S2: The clay obtained in step S1 is made into a blank by slip casting;

[0026] S3: After the green body obtained in step S2 is dried, it is placed in a gas-fired kiln. It is first sintered in an oxidizing atmosphere, and then switched to a strong reducing atmosphere when the temperature reaches 620℃. The maximum sintering temperature is 1110℃, and the firing cycle is 4.5 hours. The firing curve of the firing process is divided into six stages: Stage 1: Firing temperature: 50-350℃, firing time: 0.5 hours; Stage 2: Firing temperature: 350-550℃, firing time: 0.5 hours; Stage 3: Firing temperature: 550-620℃, firing time: 1 hour; Stage 4: Firing temperature: 620-980℃, firing time: 1 hour; Stage 5: Firing temperature: 980℃-1110℃, firing time: 1 hour; Stage 6: Holding at the maximum sintering temperature for 0.5 hours, and then slowly cooling after firing to obtain the black pottery.

[0027] In this embodiment, in step S1, the particle size D50 of the mud is 8μm, the mud specific gravity is 1.78, the material:ball:water ratio is 1:2:0.3, the speed of the ball mill is 60r / min, and the ball milling time is 4h.

[0028] In this embodiment, in step S2, the thickness of the prepared blank is 6mm, and in step S3, at 900℃, the length of the strong reducing flame passing through the observation hole is 15-20cm.

[0029] The black pottery produced in this embodiment is like... Figure 1 As shown, its apparent porosity is ≥30%.

[0030] Example 2

[0031] This embodiment provides a method for preparing black pottery using a low-temperature strong reduction carbonization process, including the following steps:

[0032] S1: Weigh 52 parts of silicon dioxide, 20 parts of aluminum oxide, 1.3 parts of potassium oxide, 1.1 parts of sodium oxide, 0.4 parts of calcium oxide, 0.2 parts of magnesium oxide, 2 parts of titanium oxide, 8 parts of iron oxide, and 3 parts of manganese oxide, add water and ball mill to obtain mud; some of the raw materials are from clay.

[0033] S2: The clay obtained in step S1 is made into a blank by slip casting;

[0034] S3: After the green body obtained in step S2 is dried, it is placed in a gas-fired kiln. It is first sintered in an oxidizing atmosphere, and then switched to a strong reducing atmosphere when the temperature reaches 620℃. The maximum sintering temperature is 1100℃, and the firing cycle is 4.5 hours. The firing curve of the firing process is divided into six stages: Stage 1: Firing temperature: 50-350℃, firing time: 0.5 hours; Stage 2: Firing temperature: 350-550℃, firing time: 0.5 hours; Stage 3: Firing temperature: 550-620℃, firing time: 1 hour; Stage 4: Firing temperature: 620-980℃, firing time: 1 hour; Stage 5: Firing temperature: 980℃-1100℃, firing time: 1 hour; Stage 6: Holding at the maximum sintering temperature for 0.5 hours, and then slowly cooling after firing to obtain the black pottery.

[0035] In this embodiment, in step S1, the particle size D50 of the mud is 8.5 μm, the mud specific gravity is 1.75, the material:ball:water ratio is 1:2:0.3, the speed of the ball mill is 60 r / min, and the ball milling time is 4 h.

[0036] In this embodiment, in step S2, the thickness of the blank is 5mm, and in step S3, at 900℃, the length of the strong reducing flame passing through the observation hole is 15-20cm.

[0037] The black pottery prepared in this embodiment has an apparent porosity of ≥30%.

[0038] Example 3

[0039] This embodiment provides a method for preparing black pottery using a low-temperature strong reduction carbonization process, including the following steps:

[0040] S1: Weigh 56 parts of silicon dioxide, 23 parts of aluminum oxide, 1.5 parts of potassium oxide, 1.3 parts of sodium oxide, 0.2 parts of calcium oxide, 0.4 parts of magnesium oxide, 2 parts of titanium oxide, 10 parts of iron oxide, and 6 parts of manganese oxide, add water and ball mill to obtain mud; some of the raw materials are from clay.

[0041] S2: The clay obtained in step S1 is made into a blank by slip casting;

[0042] S3: After the green body obtained in step S2 is dried, it is placed in a gas-fired kiln. It is first sintered in an oxidizing atmosphere, and then switched to a strong reducing atmosphere when the temperature reaches 620℃. The maximum sintering temperature is 1105℃, and the firing cycle is 4.5 hours. The firing curve of the firing process is divided into six stages: Stage 1: Firing temperature: 50-350℃, firing time: 0.5 hours; Stage 2: Firing temperature: 350-550℃, firing time: 0.5 hours; Stage 3: Firing temperature: 550-620℃, firing time: 1 hour; Stage 4: Firing temperature: 620-980℃, firing time: 1 hour; Stage 5: Firing temperature: 980℃-1105℃, firing time: 1 hour; Stage 6: Holding at the maximum sintering temperature for 0.5 hours, and then slowly cooling out of the kiln after firing to obtain the black pottery.

[0043] In this embodiment, in step S1, the particle size D50 of the mud is 7.5 μm, the mud specific gravity is 1.80, the material:ball:water ratio is 1:2:0.3, the rotation speed of the ball mill is 60 r / min, and the ball milling time is 4 h.

[0044] In this embodiment, in step S2, the thickness of the prepared blank is 8mm, and in step S3, at 900℃, the length of the strong reducing flame passing through the observation hole is 15-20cm.

[0045] The black pottery prepared in this embodiment has an apparent porosity of ≥30%.

[0046] Comparative Example 1

[0047] The difference from Example 1 is that the black pottery of this comparative example is composed of the following raw materials in parts by weight: 54 parts silicon dioxide, 19 parts aluminum oxide, 1.2 parts potassium oxide, 1.2 parts sodium oxide, 0.3 parts calcium oxide, 0.25 parts magnesium oxide, 0.8 parts titanium oxide, 4 parts iron oxide, and 2 parts manganese oxide.

[0048] Comparative Example 2

[0049] The difference from Example 1 is that the black pottery of this comparative example is composed of the following raw materials in parts by weight: 60 parts silicon dioxide, 24 parts aluminum oxide, 1.2 parts potassium oxide, 1.2 parts sodium oxide, 0.3 parts calcium oxide, 0.25 parts magnesium oxide, 1.8 parts titanium oxide, 12 parts iron oxide, and 8 parts manganese oxide.

[0050] Comparative Example 3

[0051] The difference from Example 1 is that the reducing atmosphere conversion point of this comparative example is 50°C, and a reducing atmosphere is used for firing throughout.

[0052] Comparative Example 4

[0053] The difference from Example 1 is that the reducing atmosphere conversion point of this comparative example is 900°C.

[0054] Comparative Example 5

[0055] The reducing atmosphere conversion point of this comparative example is 1100℃, and it is kept at approximately 1110℃ for 30 minutes.

[0056] Implementation effect evaluation

[0057] The following specific experiments on the black pottery obtained in Examples 1-3 and Comparative Examples 1-5 further illustrate the excellent effects achieved by the present invention. The test results are shown in the table below:

[0058] Table 1 Performance Test Results Statistics

[0059]

[0060]

[0061] As can be seen from the data in the table above, the black pottery prepared in Example 1 has a uniform and aesthetically pleasing black outer shell; therefore, Example 1 is used as a blank control. The black pottery in Examples 2 and 3 both meet the acceptable standards in terms of color and strength. The pottery prepared in Comparative Example 1 is grayish in color. The pottery prepared in Comparative Example 2 is brownish-black, deviating from the color of black pottery. The pottery prepared in Comparative Example 3 is grayish, lacking the color of black pottery. The pottery prepared in Comparative Example 4 is brownish-red, deviating from the color of black pottery. The black pottery prepared in Comparative Example 5 is light gray, lacking the color of black pottery. Furthermore, the strength of the pottery in Comparative Examples 1-5 is somewhat reduced. This indicates that the black pottery prepared by the method of preparing black pottery using a low-temperature strong reduction carbonization process provided by this invention has good appearance properties, with a uniform and aesthetically pleasing black outer shell, and high strength.

[0062] The above description is only a preferred embodiment of the present invention. It should be noted that those skilled in the art can make several modifications and improvements without departing from the inventive concept of the present invention, and these all fall within the protection scope of the present invention.

Claims

1. A method for preparing black pottery using a low-temperature strong reduction carbonization process, characterized in that, Includes the following steps: S1: Weigh 52-56 parts of silicon dioxide, 20-23 parts of aluminum oxide, 1.2-1.5 parts of potassium oxide, 1.1-1.3 parts of sodium oxide, 0.2-0.4 parts of calcium oxide, 0.2-0.4 parts of magnesium oxide, 1.5-2 parts of titanium oxide, 8-10 parts of iron oxide, and 3-6 parts of manganese oxide, add water and ball mill to obtain mud; some of the raw materials come from clay; S2: The clay obtained in step S1 is made into a blank by slip casting; S3: After the green body obtained in step S2 is dried, it is placed in a gas-fired kiln. It is first sintered in an oxidizing atmosphere, and then switched to a strong reducing atmosphere when the temperature reaches 620℃. The maximum sintering temperature is 1100-1110℃, and the firing cycle is 4.5 hours. The firing curve of the firing process is divided into six stages: Stage 1: Firing temperature 50-350℃, firing time 0.5 hours; Stage 2: Firing temperature 350-550℃, firing time 0.5 hours; Stage 3: Firing temperature 550-620℃, firing time 1 hour; Stage 4: Firing temperature 620-980℃, firing time 1 hour; Stage 5: Firing temperature 980℃ to the maximum sintering temperature, firing time 1 hour; Stage 6: Holding at the maximum sintering temperature for 0.5 hours, and then slowly cooling after firing to obtain the black pottery.

2. The method for preparing black pottery using a low-temperature strong reduction carbonization process according to claim 1, characterized in that, In step S1, the particle size D50 of the mud is 7.5-8.5μm and the mud specific gravity is 1.75-1.

80.

3. The method for preparing black pottery using a low-temperature strong reduction carbonization process according to claim 1, characterized in that, In step S1, during the ball milling process, the ratio of material:balls:water is 1: The ratio was 2:0.3, the ball mill speed was 60 r / min, and the ball milling time was 4 h.

4. The method for preparing black pottery using a low-temperature strong reduction carbonization process according to claim 1, characterized in that, In step S2, the thickness of the blank is 5-8 mm.

5. The method for preparing black pottery using a low-temperature strong reduction carbonization process according to claim 1, characterized in that, In step S3, at 900℃, the length of the strong reducing flame passing through the observation hole is 15-20cm.

6. Black pottery prepared by a method for preparing black pottery using a low-temperature strong reduction carbonization process according to any one of claims 1-5.

7. The black pottery prepared by the method of low-temperature strong reduction carbonization process according to claim 6, characterized in that, The apparent porosity of the black pottery is ≥30%.

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