Low-temperature fast-fired high water absorption wet-process powder compact and preparation method and application thereof

Abstract

The application relates to the technical field of building ceramics, and discloses a high-water-absorption wet-method powdering green body with low-temperature fast firing, a preparation method and application, wherein the water absorption of the high-water-absorption wet-method powdering green body is greater than 0.5% and less than or equal to 3.0% according to the mass percentage, the firing temperature is less than or equal to 1100 DEG C, and the firing period is less than or equal to 30 min; the high-water-absorption wet-method powdering green body is pressed and fired from high-water-absorption wet-method powder, and the high-water-absorption wet-method powder is prepared by a wet-method powdering process; the chemical composition of the high-water-absorption wet-method powder comprises Al2O3, CaO, MgO, K2O and Na2O, and according to the mass percentage, the content of Al2O3 in the high-water-absorption wet-method powder is 16.2-17.2%, the total content of CaO, MgO, K2O and Na2O is 5.3-6.3%, the content of CaO is greater than or equal to 0.8%, the content of MgO is greater than or equal to 1.6%, the content of K2O is greater than or equal to 1.5%, and the content of Na2O is greater than or equal to 1.4%. The high-water-absorption wet-method powdering green body with low-temperature fast firing, the preparation method and the application can realize low-temperature fast firing of the green body, reduce energy consumption and carbon emission, and effectively improve the roller rod marks caused by excessive softening.

Description

Technical Field

[0001] This invention relates to the field of building ceramics technology, and in particular to a low-temperature fast-firing wet-process powdered green body with high water absorption rate, its preparation method, and its application. Background Technology

[0002] In the field of building ceramics technology, reducing firing energy consumption is a crucial aspect of lowering production costs and improving economic efficiency. The fundamental solution to reducing the firing energy consumption of ceramic blanks lies in achieving low-temperature, rapid firing. While existing ceramic blank preparation processes have reduced firing temperatures and cycles to some extent, firing temperatures are generally still above 1140℃, and firing cycles are generally still above 45 minutes, resulting in limited energy savings.

[0003] Furthermore, after the brick body softens in the high-temperature zone of the kiln, due to insufficient skeleton strength, it is prone to deformation under its own weight and the friction of the rollers, thus forming roller marks. A common industry solution to this is to increase the aluminum content in the brick body formula to 18% (by mass percentage) to reduce excessive softening and roller marks during high-temperature firing. While this adjustment can effectively improve the roller marks, excessively increasing the aluminum content in the brick body formula leads to higher firing temperatures, making it difficult to reduce the firing energy consumption of the brick body. Summary of the Invention

[0004] The purpose of this invention is to propose a low-temperature rapid-fired, high-water-absorption wet-process powdered green body and its preparation method and application, which is beneficial to achieve low-temperature rapid firing of the green body, reduce energy consumption and carbon emissions, and can also effectively improve the roller marks caused by excessive softening during high-temperature firing, overcoming the shortcomings of the prior art.

[0005] To achieve this objective, the present invention adopts the following technical solution:

[0006] A high water absorption wet-processed powdered green body with low temperature and rapid firing, wherein the water absorption rate of the high water absorption wet-processed powdered green body is >0.5% and ≤3.0% by mass percentage, the firing temperature is ≤1100℃, and the firing cycle is ≤30min;

[0007] The high water absorption wet-process powder blank is made by pressing and firing high water absorption powder, and the high water absorption powder is obtained by wet-process powder making process;

[0008] The chemical composition of the highly hygroscopic powder includes Al2O3, CaO, MgO, K2O and Na2O. By mass percentage, the content of Al2O3 in the highly hygroscopic powder is 16.2-17.2%, the total content of CaO, MgO, K2O and Na2O is 5.3-6.3%, the content of CaO is ≥0.8%, the content of MgO is ≥1.6%, the content of K2O is ≥1.5%, and the content of Na2O is ≥1.4%.

[0009] Preferably, the chemical composition of the highly hygroscopic powder includes loss on ignition, and the content of loss on ignition in the highly hygroscopic powder is ≤5.5% by mass percentage.

[0010] Preferably, the chemical composition of the highly hygroscopic powder, by mass percentage, includes 68.2–70.5% SiO2, 16.2–17.2% Al2O3, 1.4–2.5% Fe2O3, 0.2–0.4% TiO2, 0.8–1.2% CaO, 1.6–2.2% MgO, 1.5–1.7% K2O, 1.4–1.6% Na2O, and 3.8–5.5% loss on ignition.

[0011] Preferably, the raw materials of the high hygroscopic powder are composed of 4% bentonite, 6% bauxite, 18% green sand, 1.5% magnesia, 15% broken brick powder, 16% mixed mud, 16% grinding and polishing mud, 1% talc and 22.5% yellow sand by mass percentage.

[0012] Preferably, the thickness of the wet-processed powder blank with high water absorption rate is 6.8 to 7.4 mm.

[0013] A method for preparing a high water absorption wet-processed powder compact by low-temperature rapid firing, comprising the following steps:

[0014] A. Mix the raw materials of the highly hygroscopic powder according to the formula, add water and ball mill to obtain a slurry;

[0015] B. The slurry is sprayed into the spray granulation tower and spray granulation is performed to obtain highly hygroscopic powder.

[0016] C. After pressing the highly hygroscopic powder, it is fired in a kiln to obtain a wet powder blank with high water absorption rate.

[0017] In step A, the ball milling fineness of the slurry is such that it passes through a 325-mesh sieve, and the sieve residue is 2.7-3.2% by mass percentage.

[0018] Preferably, in step A, the water content of the slurry is 32-35% by mass percentage.

[0019] Preferably, in step B, the moisture content of the highly hygroscopic powder is 5.8% to 6.8% by mass percentage;

[0020] In step B, the particle size distribution of the highly hygroscopic powder is as follows, by mass percentage: ≤4.0% residue on a 20-mesh sieve, 55-70% residue on a 40-mesh sieve, 80-95% residue on a 60-mesh sieve, and ≥97% residue on a 100-mesh sieve.

[0021] Application of a low-temperature fast-firing, high-water-absorption wet-process powder-prepared body in the preparation of glazed tiles, using the aforementioned high-water-absorption wet-process powder-prepared body.

[0022] The technical solution provided by this invention may include the following beneficial effects:

[0023] 1. This scheme controls the Al2O3 content in the high hygroscopic powder to be 16.2-17.2%. This aluminum content range can meet the requirements of the high water absorption green body produced in this scheme in terms of resisting high temperature softening while reducing the cost of raw materials. It avoids the softening of the green body due to excessively low content, which may cause defects such as roller marks or even brick deformation. At the same time, it can also prevent the green body formula from requiring a high firing temperature due to excessively high content, which would make it impossible to achieve the low temperature fast firing mechanism required by this scheme.

[0024] 2. To match the Al2O3 content in the formula, this solution also designs the fluxing system of the green body formula as a quaternary system of CaO-MgO-K2O-Na2O. In addition to controlling the total content of the fluxing components, the content of each individual fluxing component is also controlled. Utilizing the gradient fluxing effect provided by the quaternary fluxing system, the product is less prone to rapid softening of the liquid phase during high-temperature firing due to a single flux, thus preventing excessive softening of the green body. Furthermore, the optimized total content range of the fluxing components in this solution can reduce the density of the green body formula while lowering the cost of raw materials, thereby increasing the water absorption rate of the green body and meeting the market demand for low-value, low-performance ceramic products. Detailed Implementation

[0025] This technical solution provides a high water absorption wet-processed powder blank with low temperature and fast firing. According to the mass percentage, the water absorption rate of the high water absorption wet-processed powder blank is >0.5% and ≤3.0%, the firing temperature is ≤1100℃, and the firing cycle is ≤30min.

[0026] The high water absorption wet-process powder blank is made by pressing and firing high water absorption powder, and the high water absorption powder is obtained by wet-process powder making process;

[0027] The chemical composition of the highly hygroscopic powder includes Al2O3, CaO, MgO, K2O and Na2O. By mass percentage, the content of Al2O3 in the highly hygroscopic powder is 16.2-17.2%, the total content of CaO, MgO, K2O and Na2O is 5.3-6.3%, the content of CaO is ≥0.8%, the content of MgO is ≥1.6%, the content of K2O is ≥1.5%, and the content of Na2O is ≥1.4%.

[0028] To achieve low-temperature rapid firing of the green body (specifically referring to a firing temperature ≤1100℃ and a firing cycle ≤30min) and improve the roller marks caused by excessive softening during high-temperature firing, this technical solution proposes a low-temperature rapid firing formula for a high-water-absorption wet-process powder-made green body. The aim is to meet the market demand for low-value, low-performance ceramic products (specifically referring to 0.5 < E (green body water absorption) ≤3.0%, and the green body is made from wet-process powder) while reducing energy consumption and carbon emissions, and improving production efficiency.

[0029] It should be noted that the water absorption rate of the green body mainly affects the strength of the ceramic product, and the strength of the ceramic product also determines its market positioning. Generally speaking, the higher the water absorption rate, the lower the strength of the ceramic product, making it suitable for the low-end market. The firing temperature in this scheme is measured by the British POLAR thermometer ring, which reflects the equivalent temperature corresponding to the comprehensive thermal effect experienced at the location where the thermometer ring is placed during the entire actual firing process.

[0030] Specifically, this scheme first controls the Al2O3 content in the high hygroscopic powder to 16.2-17.2%. This aluminum content range can meet the requirements of the high water absorption green body produced in this scheme in terms of resisting high temperature softening while reducing the cost of raw materials. It avoids the softening of the green body due to excessively low content, which can cause defects such as roller marks or even brick deformation. At the same time, it can also prevent the green body formula from requiring a high firing temperature due to excessively high content, which would make it impossible to achieve the low temperature fast firing mechanism required by this scheme.

[0031] Furthermore, to adapt to the Al2O3 content in the formula, this solution designs the fluxing system of the green body formula as a quaternary system of CaO-MgO-K2O-Na2O. In addition to controlling the total content of the fluxing components, the content of each individual fluxing component is also controlled. Utilizing the gradient fluxing effect provided by the quaternary fluxing system, the product is less prone to rapid softening of the liquid phase during high-temperature firing due to a single flux, thus preventing excessive softening of the green body. Moreover, the optimized total content range of the fluxing components in this solution can reduce the density of the green body formula while lowering the cost of the raw materials, thereby increasing the water absorption rate of the green body and meeting the market demand for low-value, low-performance ceramic products.

[0032] To further clarify, the chemical composition of the highly hygroscopic powder includes loss on ignition, and the content of loss on ignition in the highly hygroscopic powder is ≤5.5% by mass percentage.

[0033] In one specific embodiment, this solution also controls the loss on ignition (IL) of the highly hygroscopic powder formulation to below 5.5% to reduce gaseous products generated in the green body and ensure the quality of the green body.

[0034] To further explain, the chemical composition of the highly hygroscopic powder, by mass percentage, includes 68.2–70.5% SiO2, 16.2–17.2% Al2O3, 1.4–2.5% Fe2O3, 0.2–0.4% TiO2, 0.8–1.2% CaO, 1.6–2.2% MgO, 1.5–1.7% K2O, 1.4–1.6% Na2O, and 3.8–5.5% loss on ignition.

[0035] Furthermore, in order to ensure the stability of the green body's performance throughout the entire process of forming, drying, and firing, while meeting the performance requirements of this application, this solution proposes a specific embodiment of the chemical composition of the highly hygroscopic powder.

[0036] It should be noted that those skilled in the art can configure the chemical composition of the highly hygroscopic powder in this scheme according to the local raw material resources. This scheme does not limit the composition and proportion of the raw materials.

[0037] To further explain, the raw materials of the highly hygroscopic powder, by mass percentage, consist of 4% bentonite, 6% bauxite, 18% green sand, 1.5% magnesia, 15% broken brick powder, 16% mixed mud, 16% edge grinding and polishing mud, 1% talc and 22.5% yellow sand.

[0038] In a preferred embodiment of this technical solution, a specific raw material ratio scheme for highly hygroscopic powder is also proposed.

[0039] In this raw material formula, the main role of bentonite is to improve the plasticity and strength of the green body during molding and transportation, and reduce the occurrence of broken bricks.

[0040] Bauxite, the most common raw material in ceramic tile production, is mainly composed of hydrous / soft boehmite. Its function is to increase the Al2O3 content in the formula and its resistance to softening during high-temperature firing. At the same time, mixed clay is introduced into the raw material formula to supplement the Al2O3 in the chemical composition. Since the main mineral of the mixed clay is kaolinite, it is easier to sinter than hydrous / soft boehmite, thus ensuring the strength during the molding process and the high-temperature resistance during high-temperature firing.

[0041] Green sand is a type of sand material, mainly produced in Rongchang District and Yongchuan District of Chongqing. It is a unique ceramic raw material in the area. This type of raw material has good firing plasticity and large reserves, making it easy to obtain. If it is added in large quantities to the body formula, the cost of raw materials can be greatly reduced. At the same time, because the chemical composition of green sand also contains a certain amount of MgO, K2O and Na2O, it has a good fluxing effect.

[0042] Magnesia clay, as the main source of MgO in chemical composition, has the effects of fluxing and whitening to a certain extent; in addition, talc, as a supplementary source of MgO in chemical composition, can increase the stability of the formula when the two are combined.

[0043] Yellow sand is also a cheap and white raw material in Chongqing, which has good economic benefits. However, because the Al2O3 content in the raw material is extremely low, excessive use will lead to a decrease in the overall Al2O3 content of the formula, resulting in softening of the green body.

[0044] Broken brick powder is clinker formed by crushing substandard products after firing. When added to other raw materials, it can promote rapid firing of the green body layer, further reducing the energy consumption of green body production, thus effectively promoting rapid firing of the green body and shortening the firing cycle. At the same time, replacing traditional feldspar materials as a fluxing agent in the formula has a significant fluxing effect and can also effectively reduce raw material costs.

[0045] Edge grinding and polishing putty is a common waste material in the building ceramics industry, mainly generated during the edge grinding and polishing process of ceramic tiles. Its main minerals are glass phase, quartz, and mullite, with small amounts of silicon carbide and grinding resin, making it prone to foaming. As a solid waste material, its outsourced treatment is costly, and it is generally used in small quantities in the body formulation to reduce costs. However, since the purpose of this solution is to prepare bodies with high water absorption, and high water absorption produces less liquid phase during high-temperature firing, it has less impact on the exhaust of easily foaming materials such as silicon carbide and resin in the edge grinding and polishing putty. Therefore, it can be added in large quantities to the raw material formulation of this solution, achieving efficient solid waste disposal under a low-temperature rapid firing mechanism, while simultaneously ensuring product quality and cost-effectiveness.

[0046] To further clarify, the thickness of the high water absorption wet-processed powder blank is 6.8–7.4 mm.

[0047] In addition, considering that when the amount of edge polishing paste is large, the green body is prone to black core expansion during the firing process, this solution also reduces the thickness of the green body. The reduction in thickness is more conducive to reducing the generation of liquid phase, so as to facilitate the sintering and digestion of edge polishing paste.

[0048] A method for preparing a high water absorption wet-processed powder compact by low-temperature rapid firing, comprising the following steps:

[0049] A. Mix the raw materials of the highly hygroscopic powder according to the formula, add water and ball mill to obtain a slurry;

[0050] B. The slurry is sprayed into the spray granulation tower and spray granulation is performed to obtain highly hygroscopic powder.

[0051] C. After pressing the highly hygroscopic powder, it is fired in a kiln to obtain a wet powder blank with high water absorption rate.

[0052] In step A, the ball milling fineness of the slurry is such that it passes through a 325-mesh sieve, and the sieve residue is 2.7-3.2% by mass percentage.

[0053] This method appropriately improves the ball milling fineness of the slurry, which helps to reduce processing costs and increase the water absorption rate of the green body.

[0054] To further explain, in step A, the water content of the slurry is 32-35% by mass percentage.

[0055] To further clarify, in step B, the moisture content of the highly hygroscopic powder is 5.8% to 6.8% by mass percentage.

[0056] In step B, the particle size distribution of the highly hygroscopic powder is as follows, by mass percentage: ≤4.0% residue on a 20-mesh sieve, 55-70% residue on a 40-mesh sieve, 80-95% residue on a 60-mesh sieve, and ≥97% residue on a 100-mesh sieve.

[0057] Application of a low-temperature fast-firing, high-water-absorption wet-process powder-prepared body in the preparation of glazed tiles, using the aforementioned high-water-absorption wet-process powder-prepared body.

[0058] The technical solution of the present invention will be further illustrated below through specific embodiments.

[0059] Example group

[0060] A. Mix the raw materials of the highly hygroscopic powder, add water and ball mill to obtain a slurry;

[0061] B. The slurry is sprayed into the spray granulation tower and spray granulation is performed to obtain highly hygroscopic powder.

[0062] C. After pressing the highly hygroscopic powder, it is fired in a kiln to obtain a wet powder blank with high water absorption rate.

[0063] In step A, the raw materials for the highly hygroscopic powder are composed of bentonite, bauxite, green sand, magnesia, broken brick powder, mixed mud, edge polishing mud, talc and yellow sand; the ball milling fineness of the slurry is to pass through a 325-mesh sieve, and the sieve residue is 2.7-3.2% by mass percentage; the water content of the slurry is 32-35% by mass percentage.

[0064] Specifically, by mass percentage, the chemical composition of the bauxite includes 41.64% SiO2, 40.99% Al2O3, 1.59% Fe2O3, 1.08% TiO2, 0.29% CaO, 0.38% MgO, 0.65% K2O, 0.31% Na2O, and 12.89% loss on ignition.

[0065] The chemical composition of the bentonite, by mass percentage, includes 68.45% SiO2, 14.57% Al2O3, 0.81% Fe2O3, 0.11% TiO2, 1.48% CaO, 1.59% MgO, 2.91% K2O, 1.67% Na2O, and 7.02% loss on ignition.

[0066] According to mass percentage, the chemical composition of the green sand includes 69.51% SiO2, 14.73% Al2O3, 3.19% Fe2O3, 0.31% TiO2, 1.41% CaO, 1.83% MgO, 1.74% K2O, 3.87% Na2O and 2.59% loss on ignition.

[0067] The chemical composition of the magnesian clay, by mass percentage, includes 62.59% SiO2, 5.79% Al2O3, 1.62% Fe2O3, 0.13% TiO2, 0.79% CaO, 1.41% MgO, 0.25% K2O, 0.25% Na2O, and 6.04% loss on ignition.

[0068] The chemical composition of the broken brick powder, by mass percentage, includes 65.67% SiO2, 18.0% Al2O3, 1.75% Fe2O3, 0.5% TiO2, 0.62% CaO, 1.77% MgO, 1.92% K2O, and 2.09% Na2O.

[0069] The chemical composition of the mixed mud, by mass percentage, includes 69.35% SiO2, 20.5% Al2O3, 0.94% Fe2O3, 0.43% TiO2, 0.98% CaO, 0.3% MgO, 1.06% K2O, 0.17% Na2O, and 7.21% loss on ignition.

[0070] The chemical composition of the edge polishing putty, by mass percentage, includes 67.48% SiO2, 18.0% Al2O3, 1.6% Fe2O3, 0.38% TiO2, 2.12% CaO, 2.46% MgO, 2.05% K2O, 2.14% Na2O, and 1.77% loss on ignition.

[0071] The chemical composition of the talc, by mass percentage, includes 32.24% SiO2, 0.69% Al2O3, 0.22% Fe2O3, 0.03% TiO2, 1.76% CaO, 37.57% MgO, 0.01% K2O, 0.09% Na2O, and 27.0% loss on ignition.

[0072] The chemical composition of the yellow sand, by mass percentage, includes 79.63% SiO2, 9.53% Al2O3, 0.65% Fe2O3, 0.22% TiO2, 0.24% CaO, 0.32% MgO, 1.63% K2O, 0.22% Na2O, and 2.8% loss on ignition.

[0073] In step B, the moisture content of the highly hygroscopic powder is 6.3% by mass percentage; the particle size distribution of the highly hygroscopic powder is as follows by mass percentage: 4.0% residue on a 20-mesh sieve, 60% residue on a 40-mesh sieve, 90% residue on a 60-mesh sieve, and 97% residue on a 100-mesh sieve. The highly hygroscopic powders of Examples 1-3 are obtained by rationally configuring the raw materials from step A, and the corresponding chemical compositions are shown in Table 1 below.

[0074] In step C, the firing temperature is 1100℃ (measured by a British Pluton temperature measuring ring), and the firing cycle is 29.34 min; the size of the high water absorption wet-process powdered green body is 800 specification (800mm×800mm) and the thickness is 7.4mm.

[0075] Table 1 Chemical composition of the highly hygroscopic powders from Examples 1-3

[0076]

[0077] It should be noted that the total content of the chemical components listed in Examples 1-3 in Table 1 is less than 100%, and the remaining content is an unavoidable impurity in the formulation system.

[0078] The condition of the high water absorption wet-process powdered green bodies after firing in Examples 1-3 was observed, and the corresponding performance tests were conducted on the fired green bodies according to the test methods of the People's Republic of China National Standards GB / T 4100-2015 and GB / T 45817-2025. The results are shown in Table 2 below:

[0079] Table 2 Performance test results of Examples 1-3

[0080]

[0081] As shown in Table 2, the performance test results indicate that this scheme optimizes the chemical composition of the high hygroscopic powder, which is beneficial for achieving low-temperature rapid firing of the green body, reducing firing energy consumption, and effectively improving the roller marks caused by excessive softening during high-temperature firing. The performance test results of the roller marks meet the standard of GB / T 45817—2025, and the other performance test results meet the standard of GB / T 4100-2015.

[0082] The technical principles of the present invention have been described above with reference to specific embodiments. These descriptions are merely for explaining the principles of the invention and should not be construed as limiting the scope of protection of the invention in any way. Based on this explanation, those skilled in the art can readily conceive of other specific embodiments of the invention without inventive effort, and these embodiments will all fall within the scope of protection of the present invention.

Claims

1. A low-temperature fast-firing high water absorption wet-method powdering compact, characterized by: The high water absorption rate wet powdering body has a water absorption rate of >0.5% and ≤3.0% according to the mass percentage, and a firing temperature of ≤1100℃ and a firing period of ≤30min; The high water absorption rate wet powdering body is prepared by pressing and firing the high water absorption rate wet powder, and the high water absorption rate wet powder is prepared by a wet powdering process; The high water absorption rate wet powder has a chemical composition including SiO268.2-70.5%, Al2O316.2-17.2%, Fe2O31.4-2.5%, TiO20.2-0.4%, CaO 0.8-1.2%, MgO 1.6-2.2%, K2O 1.5-1.7%, Na2O 1.4-1.6% and a loss on ignition of 3.8-5.5% according to the mass percentage, and a total content of CaO, MgO, K2O and Na2O in the high water absorption rate wet powder of 5.3-6.3%.

2. The low-temperature fast-burning high water absorption wet-method powdering body according to claim 1, characterized in that: The raw materials of the high water absorption rate wet powder include bentonite 4%, bauxite 6%, green sand 18%, magnesia soil 1.5%, broken brick powder 15%, mixed mud 16%, edge grinding and polishing mud 16%, talc 1% and yellow sand 22.5% according to the mass percentage; The broken brick powder is a clinker formed by crushing a secondary waste product after firing; The edge grinding and polishing mud is a waste residue generated in the process of grinding and polishing ceramic tiles.

3. The low temperature fast firing high water absorbing rate wet process powder compact body according to claim 2, characterized in that: The high water absorption rate wet powdering body has a thickness of 6.8-7.4mm.

4. A method for preparing a low-temperature fast-firing high water absorption wet-process powder compact, characterized by, The method for preparing the high water absorption rate wet powdering body according to any one of claims 1-3 comprises the following steps: A. mixing the raw materials of the high water absorption rate wet powder according to the formula, and ball milling to obtain a slurry; B. spraying the slurry into a spray granulation tower to obtain the high water absorption rate wet powder by spray granulation; C. pressing the high water absorption rate wet powder, and firing in a kiln to obtain the high water absorption rate wet powdering body; In step A, the ball milling fineness of the slurry is passed through a 325 mesh screen, and the residue on the screen is 2.7-3.2% according to the mass percentage.

5. The method according to claim 4, wherein the method is characterized by: In step A, the water content of the slurry is 32-35% according to the mass percentage.

6. The method according to claim 5, wherein the method is characterized by: In step B, the water content of the high water absorption rate wet powder is 5.8-6.8% according to the mass percentage; In step B, the particle size distribution of the high water absorption rate wet powder is as follows according to the mass percentage: a residue on a 20 mesh screen ≤4.0%, a residue on a 40 mesh screen 55-70%, a residue on a 60 mesh screen 80-95%, and a residue on a 100 mesh screen ≥97%.

7. Use of a low-temperature fast-firing high water absorption wet-process powder body in the production of glazed tiles, characterized in that, The high water absorption rate wet powdering body according to any one of claims 1-3 is used.

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