Low-expansion ceramic cookware blank with low water absorption rate and high thermal shock resistance and preparation method of cookware product of low-expansion ceramic cookware blank

Abstract

The invention discloses a low-expansion ceramic cookware blank with low water absorption and high thermal shock resistance and a preparation method of a cookware product. The blank is prepared from the following raw materials: 25 to 45 weight percent of fused quartz, 5 to 10 weight percent of potassium feldspar powder, 15 to 25 weight percent of washing mud, 10 to 20 weight percent of knar clay, 8 to 12 weight percent of chlorite, 3 to 7 weight percent of ball clay, 5 to 10 weight percent of microcrystalline glass leftover material and 5 to 10 weight percent of activated aluminum oxide. The ceramic blank is sintered at the temperature of 1240-1260 DEG C. The water absorption rate of the obtained cookware product is 4.5-5.8%, the expansion coefficient alpha (800-20 DEG C) is less than or equal to 1.6 * 10 <-6 > / DEG C, and the thermal shock resistance is that the cookware product does not crack after being cooled by water for five times at the temperature of 460-20 DEG C. Through formula design, the technical problem that in the prior art, a fused quartz formula system is large in water absorption is solved, the prepared ceramic pot product is low in water absorption, thermal shock resistance and other properties are remarkably improved, the use requirements of low-expansion ceramic products such as a heat-resistant pot can be well met, and the requirements for matched use of electric appliances, high-temperature resistance and the like can be met. And the technical progress and application development of the low-expansion ceramic industry can be promoted.

Description

Technical Field

[0001] The invention relates to the technical field of ceramic materials, and in particular to a low-expansion ceramic cookware blank with low water absorption and high thermal shock resistance and a preparation method of the cookware product. Background Art

[0002] The main raw material of low-expansion ceramic cookware is lithium-containing mineral raw materials. However, in recent years, due to the country's new energy battery strategy, the consumption of lithium-containing minerals has increased, and high-quality spodumene, as a strategic resource, has become more and more difficult to obtain. In this way, due to the serious shortage of spodumene supply and the exponential increase in material costs, traditional low-expansion ceramic companies such as cookware have suffered a fatal blow, and production has been difficult to maintain. In view of this, most companies currently use methods that are nothing more than reducing the amount of spodumene or adopting lithium-free formulas, but this causes the water absorption rate of ceramic cookware to increase and the thermal shock resistance to deteriorate. Some studies have used lithium-containing minerals and cordierite clinker for batching, but the forming performance is poor, it is difficult to sinter, the water absorption rate is large, and the expansion coefficient is also large (reaching α (800～20℃) =2.6×10 -6 / ℃), and there are many defects such as mismatch with ceramic glaze. In addition, a high heat-resistant ceramic cookware has been developed using fused quartz and glass lithium as the main raw materials. Although the thermal shock resistance is good, the water absorption rate is 8.5-9.5%, which cannot meet the market requirement of water absorption rate ≤6%. The existing technology also uses a combination of organic and inorganic formulation systems, using triethanolamine and polyethylene glycol as modifiers to promote sintering, but does not involve the water absorption rate problem, and triethanolamine and polyethylene glycol will produce a large amount of gas in the early stage of firing, which is detrimental to the environment. Summary of the invention

[0003] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a low-expansion ceramic cookware blank with low water absorption and high thermal shock resistance. Through formula design, chlorite and activated alumina are introduced to form cordierite in situ, and by compounding with fused quartz, combined with a small amount of potassium feldspar and microcrystalline glass scraps, while reducing the material production cost, a low-expansion ceramic blank with low water absorption and high thermal shock resistance is obtained, thereby well meeting the use requirements of low-expansion ceramic products such as heat-resistant cookware. Another purpose of the present invention is to provide a preparation method and product of a cookware product based on the above-mentioned low-expansion ceramic cookware blank.

[0004] The purpose of the present invention is achieved through the following technical solutions:

[0005] The present invention provides a low-expansion ceramic cookware blank with low water absorption and high thermal shock resistance, wherein the raw materials are as follows: 25-45wt% of fused quartz, 5-10wt% of potassium feldspar powder, 15-25wt% of washed mud, 10-20wt% of purple wood knot mud, 8-12wt% of chlorite, 3-7wt% of ball clay, 5-10wt% of microcrystalline glass scraps, and 5-10wt% of activated alumina; the particle size of the fused quartz is 120-220μm; the ceramic blank is sintered at a temperature of 1240-1260°C, and the water absorption of the obtained cookware product is 4.5-5.8%, and the expansion coefficient is α (800～20℃) ≤1.6×10 -6 / ℃, thermal shock resistance: no cracking after five water cooling at 460-20℃.

[0006] Furthermore, the raw material composition of the ceramic cookware blank of the present invention is 30-45wt% of fused quartz, 5-8wt% of potassium feldspar powder, 15-20wt% of washed mud, 10-20wt% of purple wood knot mud, 8-12wt% of chlorite, 3-7wt% of ball clay, 5-10wt% of microcrystalline glass scraps, and 5-10wt% of activated alumina.

[0007] Another object of the present invention is achieved by the following technical solutions:

[0008] The present invention provides a method for preparing a low-expansion ceramic cookware product with low water absorption and high thermal shock resistance, based on the above-mentioned ceramic cookware blank; the preparation method comprises the following steps:

[0009] (1) subjecting the raw materials except fused quartz to wet ball milling until the residue on a 250-mesh sieve is 0.05-0.2%, and then adding the fused quartz to the raw materials and stirring and dispersing them uniformly to obtain a mixed material;

[0010] (2) removing iron from the mixture, dehydrating by filter pressing, vacuum slurry kneading, molding, and drying to obtain a ceramic cookware body;

[0011] (3) After the ceramic cookware body is glazed, it is fired using a weak reduction slow firing process, that is, it is fired from room temperature in an oxidizing atmosphere to 980-1020°C, and then switched to weak reduction firing, and slowly fired to 1240-1260°C for 12-14.5 hours to obtain a low-expansion ceramic cookware product with low water absorption and high thermal shock resistance.

[0012] The low expansion ceramic cookware product is prepared by the preparation method.

[0013] The present invention has the following beneficial effects:

[0014] (1) The low-expansion ceramic cookware blank with low water absorption and high thermal shock resistance of the present invention has low blank cost and good forming performance. The introduced chlorite and activated alumina synthesize cordierite in situ at high temperature. The expansion coefficient of the blank is low through the compounding of cordierite and fused quartz, thereby improving the thermal shock resistance of the product. A small amount of potassium feldspar, activated alumina and microcrystalline glass scraps can produce low eutectic during the firing process, which can be well filled into the gap, promote sintering, and make the product have low water absorption.

[0015] (2) The blank of the present invention inhibits the crystal transformation of fused quartz during the weak reduction sintering process, thereby further improving the thermal shock resistance of the product. In addition, the use of potassium feldspar and microcrystalline glass scraps as high-temperature fluxes solves the problem of high-temperature sintering, resulting in a significant improvement in the material's low water absorption and thermal shock resistance.

[0016] (3) The present invention solves the technical problem of high water absorption of the prior art fused quartz formula system. The ceramic cookware products produced can well meet the use requirements of low-expansion ceramic products such as heat-resistant cookware, and can be used in conjunction with electrical appliances (the water absorption rate cannot be high, otherwise water seepage is likely to occur), which is conducive to promoting the technological progress and application development of the low-expansion ceramic industry.

[0017] The present invention will be described in further detail below with reference to the embodiments. DETAILED DESCRIPTION

[0018] The embodiment of the present invention provides a low expansion ceramic cookware blank with low water absorption and high thermal shock resistance, and the raw material composition thereof is shown in Table 1.

[0019] Table 1 Raw material composition (wt%) of low-expansion ceramic cookware blank with low water absorption and high thermal shock resistance according to the present invention

[0020]

[0021] Among them, the particle size of fused quartz is 120 to 220 μm.

[0022] The present invention provides a method for preparing a low-expansion ceramic cookware product with low water absorption and high thermal shock resistance, based on the above ceramic cookware blank; the preparation method comprises the following steps:

[0023] (1) subjecting the raw materials except fused quartz to wet ball milling until the residue on a 250-mesh sieve is 0.05-0.2%, and then adding the fused quartz to the raw materials and stirring and dispersing them uniformly to obtain a mixed material;

[0024] (2) removing iron from the mixture, dehydrating by filter pressing, vacuum slurry kneading, molding, and drying to obtain a ceramic cookware body;

[0025] (3) After the ceramic cookware body is glazed, it is fired by a weak reduction slow firing process, that is, it is fired from room temperature in an oxidizing atmosphere to 980-1020°C, and then switched to weak reduction firing, and slowly fired to 1240-1260°C for 12-14.5 hours to obtain a low expansion ceramic cookware product with low water absorption and high thermal shock resistance.

[0026] The process parameters of each embodiment are shown in Table 2.

[0027] Table 2 Process parameters of the preparation method of low-expansion ceramic cookware products with low water absorption and high thermal shock resistance according to the embodiment of the present invention

[0028]

[0029] The performance indicators of the low-expansion ceramic cookware products with low water absorption and high thermal shock resistance in various embodiments of the present invention are shown in Table 3.

[0030] Table 3 Performance indicators of low-water absorption and high thermal shock resistance low-expansion ceramic cookware products according to the present invention

[0031]

[0032] Remark:

[0033] 1. The water absorption rate is tested using a ceramic water absorption rate meter.

[0034] 2. The expansion coefficient is tested using a PCY-1200 high-temperature thermal expansion tester.

[0035] 3. The thermal stability test adopts the national standard, that is, when the low expansion ceramic product is placed on an electric furnace and heated to a bottom temperature of 460°C, it is instantly poured into 100ml of 20°C cold water. If it is not cracked after five water coolings, it is qualified.

Claims

1. A low expansion ceramic cookware blank with low water absorption and high thermal shock resistance, characterized in that The raw materials are as follows: 25-45wt% of fused quartz, 5-10wt% of potassium feldspar powder, 15-25wt% of washed mud, 10-20wt% of purple wood knot mud, 8-12wt% of chlorite, 3-7wt% of ball clay, 5-10wt% of microcrystalline glass scraps, and 5-10wt% of activated alumina; the particle size of the fused quartz is 120-220μm; the ceramic blank is fired at a temperature of 1240-1260°C, and the water absorption rate of the obtained pot product is 4.5-5.8%, and the expansion coefficient is α (800～20℃) ≤1.6×10 -6 / ℃, thermal shock resistance: no cracking after five water cooling at 460-20℃.

2. The low expansion ceramic cookware blank with low water absorption and high thermal shock resistance according to claim 1, characterized in that: The raw material composition of the ceramic cookware blank is 30-45wt% of fused quartz, 5-8wt% of potassium feldspar powder, 15-20wt% of washed mud, 10-20wt% of purple wood knot mud, 8-12wt% of chlorite, 3-7wt% of ball clay, 5-10wt% of microcrystalline glass scraps, and 5-10wt% of activated alumina.

3. A method for preparing a low-expansion ceramic cookware product with low water absorption and high thermal shock resistance, characterized in that: Based on the ceramic cookware blank according to claim 1 or 2; the preparation method comprises the following steps: (1) subjecting the raw materials except fused quartz to wet ball milling until the residue on a 250-mesh sieve is 0.05-0.2%, and then adding the fused quartz to the raw materials and stirring and dispersing them uniformly to obtain a mixed material; (2) removing iron from the mixture, dehydrating by filter pressing, vacuum slurry kneading, molding, and drying to obtain a ceramic cookware body; (3) After the ceramic cookware body is glazed, it is fired using a weak reduction slow firing process, that is, it is fired from room temperature in an oxidizing atmosphere to 980-1020°C, and then switched to weak reduction firing, and slowly fired to 1240-1260°C for 12-14.5 hours to obtain a low-expansion ceramic cookware product with low water absorption and high thermal shock resistance.

4. A low expansion ceramic cookware product prepared by the preparation method of claim 3.

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