Composite ceramic air distributor material for coke oven and preparation method thereof

Abstract

The present invention relates to the field of composite ceramics used in coke ovens, nonferrous metallurgy, burners, and other fields. Specifically, it relates to a composite ceramic air distributor material for coke ovens and its preparation method. The raw materials include amorphous fused quartz and a composite additive. The amorphous fused quartz has the following gradation: based on the total amount of amorphous fused quartz, the portion within 8-6 mm accounts for 10-20% by weight, the portion within 5-3 mm accounts for 20-30% by weight, the portion within 2-1 mm accounts for 30-40% by weight, the portion within 0.9-0.09 mm accounts for 5-30% by weight, and the portion within 0.08-0.065 mm accounts for 5-10% by weight. Due to its refractoriness under load temperature exceeding 1650°C and thermal shock stability exceeding 100 times (water-cooled at 1100°C), the composite ceramic air distributor material can also be used in steel, coking, nonferrous metals, and other thermal equipment that must withstand temperatures below 1600°C and resist rapid cooling and heating.

Description

Technical Field

[0001] The present invention relates to the technical field of composite ceramics used in the fields of coke ovens, nonferrous smelting, burners, and the like, and in particular to a composite ceramic air distributor material for coke ovens and a preparation method thereof. Background Art

[0002] Currently, the air distributors (primarily used to disperse primary air and prevent it from directly blowing onto the coke surface and causing burns) designed for the primary air inlet at the top of heat recovery coke ovens (also known as horizontal coke ovens) are primarily made of silicon carbide, mullite, or andalusite. These distributors have a service life of less than two weeks, are expensive, and offer poor performance. Many heat recovery coke oven companies have been forced to abandon their use of these distributors. However, in these cases, excessive air blows directly onto the coke surface at the end of the coking process, creating six burn pits approximately 2 meters in diameter and 0.2 meters deep. These burns can consume approximately one ton of coke, resulting in significant economic losses for the coking plant. For a coking plant with an annual production capacity of 2 million tons, this translates to approximately 100 million yuan in direct economic losses per year (112 ovens x 1 ton per oven x 2,500 yuan / ton x 365 days). Therefore, heat recovery coke oven companies are eager to develop a new, cost-effective, and long-lasting air distributor to mitigate these losses. Summary of the Invention

[0003] The purpose of the present invention is to overcome the defects of the composite ceramic air distributor in the prior art, such as poor anti-coke burning effect, poor thermal shock resistance and short service life, and to provide a composite ceramic air distributor material for coke ovens and a preparation method thereof. The composite ceramic air distributor has good resistance to rapid cooling and heating, high temperature resistance, long life and economy, good thermal shock resistance and long service life. First, it will not undergo obvious deformation or softening at a temperature of 1450°C, and secondly, it can withstand the stress caused by the temperature difference of about 1000°C and the rapid temperature changes.

[0004] In order to achieve the above-mentioned object, the first aspect of the present invention provides a composite ceramic air distributor for a coke oven. Material The raw materials include amorphous fused quartz and composite additives. Based on the total amount of raw materials, the composite additives account for 12-40wt% and the amorphous fused quartz accounts for 60-88wt%.

[0005] The amorphous fused quartz has the following gradation: based on the total amount of amorphous fused quartz, the portion within 8-6 mm accounts for 10-20 wt%, the portion within 5-3 mm accounts for 20-30 wt%, the portion within 2-1 mm accounts for 30-40 wt%, the portion within 0.9-0.09 mm accounts for 5-30 wt%, and the portion within 0.08-0.065 mm accounts for 5-10 wt%.

[0006] The composite additive is composed of the following components in proportion by mass: based on the total amount of raw materials, 5-10wt% of silicon micropowder, 5-10wt% of microsilica powder, 1-5wt% of magnesia powder, and 1-5wt% of petalite; the particle size of the silicon micropowder is 40-60 microns, the particle size of the microsilica powder is 100-120 microns, the particle size of the magnesia powder is 40-50 microns, and the particle size of the petalite is 40-50 microns.

[0007] Preferably, the ratio of the total mass of the silicon powder and magnesia powder to the total mass of the microsilica powder and petalite is 1.

[0008] Preferably, the mass ratio of the composite additive to the amorphous fused quartz is 0.3-0.5:1.

[0009] Preferably, the raw materials of the composite ceramic air distributor for coke oven further include silica sol and phosphoric acid solution, and based on the total amount of raw materials, the silica sol is 3-5wt% and the phosphoric acid solution is 3-5wt%.

[0010] More preferably, the SiO2 content in the silica sol is ≥30wt%, and the H3PO4 content in the phosphoric acid solution is ≥70wt%.

[0011] More preferably, the SiO2 content in the silica sol is 30-50 wt%, and the H3PO4 content in the phosphoric acid solution is 70-90 wt%.

[0012] In a second aspect, the present invention provides a method for preparing a composite ceramic air distributor material for a coke oven, wherein the composite ceramic air distributor for a coke oven is the composite ceramic air distributor material for a coke oven described in the first aspect, and the preparation method comprises the following steps:

[0013] S1, raw material premixing;

[0014] S2. Wet mixing: Add the premixed material into the mixer, add silica sol and phosphoric acid solution, mix and grind until the materials are evenly mixed;

[0015] S3, molding: filling the material mixed in S2 into the mold for vibration molding;

[0016] S4, demoulding and curing;

[0017] S5. Drying: The cured product is dried. The drying process includes heating from room temperature to 150°C at a heating rate of 15-17°C / h and keeping warm for 4-5 hours; heating from 150-450°C at a heating rate of 20-22°C / h and keeping warm for 4-5 hours; cooling from 450-150°C at a cooling rate of 14-15°C / h and from 150-50°C at a cooling rate of 4-5°C / h;

[0018] S6. Loading the kiln for firing: Firing the dried products. The firing process includes: -450℃ to 450℃, heating rate of 45-46℃ / h, keeping warm for 5-6h; 450-800℃, heating rate of 23-25℃ / h, keeping warm for 2-3h; 800-1100℃, heating rate of 20-22℃ / h; 1100-500℃, cooling rate of 30-32℃ / h; 500-200℃, cooling rate of 20-24℃ / h; 300-100℃, cooling rate of 10-12℃ / h.

[0019] Preferably, the process of premixing raw materials in S1 includes: first mixing silicon micropowder and magnesia powder to obtain a first mixture, mixing the first mixture with silicon powder to obtain a second mixture, mixing the second mixture with amorphous fused quartz to obtain a third mixture, and mixing the third mixture with petalite.

[0020] Preferably, the mixing and grinding time is 3-5 minutes.

[0021] Preferably, the demoulding time in S4 is 8-10 hours, and the curing process includes: curing in a curing room at 20-30°C for 48-72 hours.

[0022] Compared with the prior art, the composite ceramic air distributor for coke ovens provided by the present invention, by adopting amorphous fused quartz of a specific gradation and composite additives of a specific composition, can evenly disperse the primary air entering from the top of the coke oven horizontally to the upper part of the top, thereby improving the combustion efficiency of the upper part of the top, avoiding the vertical blowing of cold air on the surface of the coke to cause coke burning, and reducing coke burning by about 1 ton per furnace; and has good thermal shock resistance and a long service life, among which it has the characteristics of excellent thermal shock performance, and the thermal shock stability (1100℃, water cooling) can be greater than 100 times. In the heat recovery coke oven of Hebei Taihang Iron and Steel Group Co., Ltd., the service life has been increased from 1-2 weeks of traditional materials to more than 6 months, and it is currently in stable operation.

[0023] The composite ceramic air distributor of the present invention is prepared using the above-mentioned specific raw materials through a specific preparation method (especially a specific drying process and firing process, and an optimal raw material mixing process) to obtain a specific physical network structure with rapid heat conduction, so that it no longer needs to be preheated when used in a coke oven, which not only saves energy and is more environmentally friendly, but also reduces the difficulty of use and improves the efficiency of use. DETAILED DESCRIPTION

[0024] The endpoints of the ranges and any values ​​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 endpoints of each range, the endpoints of each range and individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered to be specifically disclosed herein.

[0025] A first aspect of the present invention provides a composite ceramic air distributor for a coke oven, wherein the raw materials thereof include amorphous fused quartz and a composite additive, wherein the composite additive comprises 12-40 wt % and the amorphous fused quartz comprises 60-88 wt % based on the total amount of the raw materials.

[0026] The amorphous fused quartz has the following gradation: based on the total amount of amorphous fused quartz, the portion within 8-6 mm accounts for 10-20 wt%, the portion within 5-3 mm accounts for 20-30 wt%, the portion within 2-1 mm accounts for 30-40 wt%, the portion within 0.9-0.09 mm accounts for 5-30 wt%, and the portion within 0.08-0.065 mm accounts for 5-10 wt%.

[0027] The composite additive is composed of the following components in proportion by mass: based on the total amount of raw materials, 5-10wt% of silicon micropowder, 5-10wt% of microsilica powder, 1-5wt% of magnesia powder, and 1-5wt% of petalite; the particle size of the silicon micropowder is 40-60 microns, the particle size of the microsilica powder is 100-120 microns, the particle size of the magnesia powder is 40-50 microns, and the particle size of the petalite is 40-50 microns.

[0028] Preferably, the ratio of the total mass of the silicon powder and magnesia powder to the total mass of the microsilica powder and petalite is 1. This preferred solution is more conducive to thermal shock stability and improves service life.

[0029] Preferably, the mass ratio of the composite additive to the amorphous fused quartz is 0.3-0.5: 1. This preferred solution is more conducive to thermal shock stability and improves service life.

[0030] Preferably, the raw materials for the composite ceramic air distributor for coke ovens also include silica sol and phosphoric acid solution, with the silica sol and phosphoric acid solution comprising 3-5 wt% of the total raw materials. This preferred solution further reduces demolding time and lowers the firing temperature to below 1100°C.

[0031] More preferably, the SiO2 content in the silica sol is ≥30wt%, and the H3PO4 content in the phosphoric acid solution is ≥70wt%.

[0032] More preferably, the SiO2 content in the silica sol is 30-50 wt%, and the H3PO4 content in the phosphoric acid solution is 70-90 wt%.

[0033] In a second aspect, the present invention provides a method for preparing a composite ceramic air distributor material for a coke oven, wherein the composite ceramic air distributor for a coke oven is the composite ceramic air distributor material for a coke oven described in the first aspect, and the preparation method comprises the following steps:

[0034] S1, raw material premixing;

[0035] S2. Wet mixing: Add the premixed material into the mixer, add silica sol and phosphoric acid solution, mix and grind until the materials are evenly mixed;

[0036] S3, molding: filling the material mixed in S2 into the mold for vibration molding;

[0037] S4, demoulding and curing;

[0038] S5. Drying: The cured product is dried. The drying process includes heating from room temperature to 150°C at a heating rate of 15-17°C / h and keeping warm for 4-5 hours; heating from 150-450°C at a heating rate of 20-22°C / h and keeping warm for 4-5 hours; cooling from 450-150°C at a cooling rate of 14-15°C / h and from 150-50°C at a cooling rate of 4-5°C / h;

[0039] S6. Loading the kiln for firing: Firing the dried products. The firing process includes: -450℃ to 450℃, heating rate of 45-46℃ / h, keeping warm for 5-6h; 450-800℃, heating rate of 23-25℃ / h, keeping warm for 2-3h; 800-1100℃, heating rate of 20-22℃ / h; 1100-500℃, cooling rate of 30-32℃ / h; 500-200℃, cooling rate of 20-24℃ / h; 300-100℃, cooling rate of 10-12℃ / h.

[0040] Preferably, the process of premixing raw materials in S1 includes: first mixing silicon micropowder and magnesia powder to obtain a first mixture, mixing the first mixture with silicon powder to obtain a second mixture, mixing the second mixture with amorphous fused quartz to obtain a third mixture, and mixing the third mixture with petalite.

[0041] Preferably, the mixing and grinding time is 3-5 minutes.

[0042] Preferably, the demoulding time in S4 is 8-10 hours, and the curing process includes: curing in a curing room at 20-30°C for 48-72 hours.

[0043] The present invention will be described in detail below through examples. In the following examples, all raw materials involved are commercially available unless otherwise specified.

[0044] Example 1

[0045] A composite ceramic air distributor for a coke oven, the raw materials of which include amorphous fused quartz and a composite additive, silica sol and a phosphoric acid solution, wherein the silica sol has a SiO2 content of 40wt%, the phosphoric acid solution has a H3PO4 content of 80wt%, and the total amount of raw materials is 4wt% of silica sol, 4wt% of phosphoric acid solution, 30wt% of composite additive, and 64wt% of amorphous fused quartz; wherein the amorphous fused quartz has the following gradation: based on the total amount of amorphous fused quartz, the portion within 8-6mm accounts for 15wt%, the portion within 5-3mm accounts for 20wt%, and the portion within 5-3mm accounts for 20wt%. %, the part within 2-1mm accounts for 30wt%, the part within 0.9-0.09mm accounts for 25wt%, and the part within 0.08-0.065mm accounts for 10wt%; the composite additive is composed of the following components in proportion by mass: based on the total amount of raw materials, 10wt% of silicon micropowder, 10wt% of microsilica powder, 5wt% of magnesia powder, and 5wt% of petalite; the particle size of silicon micropowder is 40-60 microns, the particle size of microsilica powder is 100-120 microns, the particle size of magnesia powder is 40-50 microns, and the particle size of petalite is 40-50 microns.

[0046] The preparation method is as follows:

[0047] 1. Premix the raw materials. Premix the raw materials according to the ratio of the composite ceramic air distributor of the above raw materials.

[0048] 2. Wet mixing: Add the premixed composite ceramic air distributor premix into a planetary forced mixer, add silica sol and phosphoric acid solution, mix and grind for 5 minutes, and after the materials are evenly mixed, they can be discharged for vibration casting and molding.

[0049] 3. Molding: Fill the mixed material into the mold and vibrate to form it.

[0050] 4. Demolding and curing. After 9 hours, when the cast ceramic air distributor has reached the required strength for demolding, it can be demolded. After demolding, the product needs to be cured in a curing room at 25°C for 50 hours.

[0051] 5. Drying. After curing, the products can be loaded into a shuttle kiln and dried according to the drying curve below. Drying curve: Room temperature to 150°C, heating rate of 15°C / h, hold for 5 hours; 150-450°C, heating rate of 20°C / h, hold for 5 hours; 450-150°C, cooling rate of 15°C / h, 150-50°C, cooling rate of 5°C / h.

[0052] 6. Loading the kiln for firing. Load the dried products into the shuttle kiln and fire according to the firing curve below. Firing curve: -450°C to 450°C, heating rate of 45°C / h, heating time of 10 hours, holding time of 6 hours; 450-800°C, heating rate of 25°C / h, heating time of 14 hours, holding time of 2 hours; 800-1100°C, heating rate of 20°C / h, heating time of 15 hours; 1100-500°C, cooling rate of 30°C / h, cooling time of 20 hours; 500-200°C, cooling rate of 20°C / h, cooling time of 15 hours; 300-100°C, cooling rate of 10°C / h, cooling time of 20 hours.

[0053] 7. Sorting after kiln: Sorting the products out of the kiln piece by piece according to the standards and rejecting the unqualified ones.

[0054] The selected products were subjected to performance tests, and the results are shown in Table 1.

[0055] Example 2

[0056] The method of Example 1 was followed, except that the amorphous fused quartz had the following gradation: based on the total amount of amorphous fused quartz, the portion within 8-6 mm accounted for 20 wt %, the portion within 5-3 mm accounted for 20 wt %, the portion within 2-1 mm accounted for 40 wt %, the portion within 0.9-0.09 mm accounted for 15 wt %, and the portion within 0.08-0.065 mm accounted for 5 wt %.

[0057] Example 3

[0058] The method of Example 1 was followed, except that 5 wt% of microsilica powder and 10 wt% of magnesia powder were used.

[0059] Example 4

[0060] The method of Example 1 was followed, except that 40 wt % of the composite additive and 54 wt % of the amorphous fused quartz were used. The composite additive consisted of the following components in proportion by mass: based on the total amount of raw materials, 15 wt % of silicon micropowder, 15 wt % of microsilica powder, 5 wt % of magnesia powder, and 5 wt % of petalite.

[0061] Comparative Example 1

[0062] The method of Example 1 is followed, except that graded amorphous fused quartz is not used, the particle size of the amorphous fused quartz is 0.09-0.065 mm, and the total amount of the amorphous fused quartz is the same as that of Example 1.

[0063] Comparative Example 2

[0064] The method of Example 1 is followed, except that the amorphous fused quartz has the following gradation: based on the total amount of amorphous fused quartz, the portion within 0.9-0.09 mm accounts for 65 wt %, and the portion within 0.08-0.065 mm accounts for 35 wt %.

[0065] Comparative Example 3

[0066] The method of Example 1 was followed, except that no microsilica powder was added, and the microsilica powder was 20 wt%.

[0067] Comparative Example 4

[0068] The method of Example 1 is followed, except that the particle size of the microsilica powder is 40-60 μm.

[0069] Table 1

[0070]

[0071] From the analysis of the above experimental data, we can know that:

[0072] 1. The composite ceramic air distributor of the present invention uses amorphous fused quartz with excellent thermal shock resistance as its main material, which gives it excellent thermal shock resistance. The thermal shock stability (1100°C, water cooling) of the embodiments of the present invention can be greater than 100 times, laying a solid foundation for its longevity.

[0073] 2. The refractoriness of the embodiments of the present invention is higher than 1600°C, ensuring that no obvious deformation or softening will occur in the use environment below 1450°C.

[0074] 3. The expansion rate of the embodiments of the present invention is about 0.05%, which shows that the volume of the material is not sensitive to temperature changes, so that it can withstand the stress caused by the temperature difference of about 1000°C and the rapid temperature change without being damaged.

[0075] 4. When silica sol and phosphoric acid are used as binders in the present invention, there will be a problem of too long initial setting time and inability to demold, which is not conducive to mass production. The addition of composite high-performance additives can solve this problem, shortening the demolding time to 8-10 hours, and also promoting sintering, which can reduce the sintering temperature to below 1100°C, saving energy and improving production efficiency.

[0076] The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, various simple variations of the technical solution of the present invention may be made, including combining the various technical features in any other appropriate manner. These simple variations and combinations should also be regarded as disclosed in the present invention and fall within the scope of protection of the present invention.

Claims

1. A composite ceramic air distributor for a coke oven, characterized in that: The raw materials include amorphous fused quartz and composite additives. Based on the total amount of raw materials, the composite additives account for 12-40wt% and the amorphous fused quartz accounts for 60-88wt%. The amorphous fused quartz has the following gradation: based on the total amount of amorphous fused quartz, the portion within 8-6mm accounts for 10-20wt%, the portion within 5-3mm is greater than 20wt% and less than or equal to 30wt%, the portion within 2-1mm accounts for 30-40wt%, and the portion within 0.9-0.09mm accounts for 10-20wt%. The part within 0.08-0.065mm accounts for 5-30wt%, and the part within 0.08-0.065mm accounts for 5-10wt%; the composite additive is composed of the following components in proportion by mass: based on the total amount of raw materials, silicon micropowder 5-10wt%, microsilica powder 5-10wt%, magnesia powder 1-5wt%, and petalite 1-5wt%; the particle size of silicon micropowder is 40-60 microns, the particle size of microsilica powder is 100-120 microns, the particle size of magnesia powder is 40-50 microns, and the particle size of petalite is 40-50 microns.

2. The composite ceramic air distributor for coke oven according to claim 1, wherein: The ratio of the total mass of the silicon powder and the magnesia powder to the total mass of the microsilica powder and the petalite is 1.

3. The composite ceramic air distributor for coke oven according to claim 1, wherein: The mass ratio of the composite additive to the amorphous fused quartz is 0.3-0.5:

1.

4. The composite ceramic air distributor for coke oven according to claim 1, wherein: The raw materials of the composite ceramic air distributor for coke oven further include silica sol and phosphoric acid solution, and based on the total amount of raw materials, the silica sol is 3-5wt% and the phosphoric acid solution is 3-5wt%.

5. The composite ceramic air distributor for coke oven according to claim 4, wherein: The SiO2 content in the silica sol is ≥30wt%, and the H3PO4 content in the phosphoric acid solution is ≥70wt%.

6. The composite ceramic air distributor for coke oven according to claim 5, wherein: The SiO2 content in the silica sol is 30-50wt%, and the H3PO4 content in the phosphoric acid solution is 70-90wt%.

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