Special corundum mullite brick for lime kiln and preparation method thereof

Abstract

The present invention discloses a special corundum mullite brick for lime kilns and a preparation method thereof. The raw materials thereof include aggregate, silicon carbide, corundum, bauxite, fused quartz, Guangxi white mud, aluminum dihydrogen phosphate, and rare earth elements; the aggregate is formed by crushing mullite blocks; and the raw materials of the mullite blocks include ultrafine alumina powder, zircon-containing silicon powder, andalusite, kyanite, and sillimanite. The beneficial effects of the present invention are as follows: the andalusite, kyanite, sillimanite, ultrafine alumina powder, and zircon-containing silicon powder are first made into mullite blocks, which are then crushed and added as aggregate to the raw materials for preparing lime kiln bricks, so that the andalusite, kyanite, and sillimanite can be fully meshed into the mullite. The prepared special corundum mullite brick for lime kilns has high refractoriness and thermal shock resistance, has high structural strength, and has low bulk density, effectively reducing the cracking phenomenon of the lime kiln body.

Description

Technical Field

[0001] The invention relates to the technical field of special corundum mullite bricks special for lime kilns, in particular to a special corundum mullite brick special for lime kilns and a preparation method thereof. Background Art

[0002] Lime kilns are used to roast active lime and light-burned dolomite for steel and ferroalloy plants. Currently, lime kilns generally use magnesia-based bricks. While these bricks offer adequate refractory properties, they suffer from poor thermal shock resistance, low strength, high bulk density, and heavy weight, placing heavy loads on the kiln structure. These bricks are prone to cracking, head spalling, brick shedding, and lining collapse, severely damaging the kiln, leading to production stoppages and significant economic losses for the user. Furthermore, these bricks are prone to heat leakage, resulting in poor thermal insulation. Therefore, a refractory brick specifically designed for lime kilns is needed, offering high thermal shock resistance and strength while maintaining a low bulk density.

[0003] Andalusite is an aluminosilicate mineral. When heated to 1350°C under normal pressure, it begins to transform into needle-shaped mullite parallel to the original crystal. During this process, andalusite forms a well-defined mullite network, resulting in extremely high chemical stability and strong resistance to chemical corrosion. Sillimanite is a glassy silicate mineral that transforms into mullite when heated to 1300°C, exhibiting high refractoriness. Currently, there are patents for using andalusite and sillimanite directly as raw materials to make refractory bricks. However, the firing time for these bricks is generally around 10-15 hours, which is insufficient for the transformation of sillimanite and andalusite into mullite networks. Furthermore, when sillimanite and andalusite are directly mixed with other raw materials for special corundum-mullite bricks used in lime kilns, they exhibit poor thermal shock resistance. Summary of the Invention

[0004] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a special corundum mullite brick dedicated to a lime kiln and a preparation method thereof.

[0005] The object of the present invention is achieved by the following technical solution: a method for preparing special corundum-mullite bricks for lime kilns, wherein the raw materials thereof include aggregate, silicon carbide, corundum, fused quartz, Guangxi white mud, aluminum dihydrogen phosphate, and rare earth elements; the aggregate is formed by crushing mullite blocks; the raw materials of the mullite blocks include ultrafine alumina powder, zirconium-containing silicon powder, andalusite, kyanite, and sillimanite;

[0006] According to weight percentage, its raw materials include 50-65 parts of aggregate, 5-10 parts of silicon carbide, 45-55 parts of corundum, 40-45 parts of fused quartz, 20-30 parts of Guangxi white mud, 5-15 parts of aluminum dihydrogen phosphate and 0.5-1 part of rare earth elements;

[0007] According to weight percentage, the raw materials constituting the mullite block include 10 to 100 parts of ultrafine alumina powder, 10 to 100 parts of zirconium-containing silicon powder, 10 to 100 parts of andalusite, 10 to 100 parts of kyanite, and 10 to 100 parts of sillimanite;

[0008] The rare earth element is one or both of cerium oxide and yttrium oxide;

[0009] Prepared by the following steps:

[0010] 1) Prepare mullite blocks for later use;

[0011] 2) Crushing abrasive stones into aggregate;

[0012] 3) Mix the raw materials according to the proportion;

[0013] 4) Molding, drying and calcining;

[0014] The specific steps of step 1) are: mixing ultrafine alumina powder, zirconium-containing silicon powder, andalusite, kyanite, and sillimanite in proportion, vacuum extruding, block making, and calcining to obtain mullite blocks;

[0015] The calcination temperature is 1600° C. to 1750° C., and the calcination time is 1 hour to 10 hours;

[0016] The present invention also provides a special corundum mullite brick specially used for a lime kiln, which is prepared by adopting the preparation method of the special corundum mullite brick specially used for a lime kiln.

[0017] The present invention has the following advantages:

[0018] 1. The present invention combines sillimanite, andalusite, and kyanite with ultrafine alumina powder and zirconium-containing silicon powder to make mullite, ensuring that sillimanite, andalusite, and kyanite can be transformed into mullite mesh at high temperature before being used as raw materials for special corundum mullite bricks for lime kilns, thereby reducing the bulk density of the aggregate and making it have higher fire resistance and stability; the mullite blocks made of sillimanite, andalusite, and kyanite as raw materials are crushed and added as aggregate to the raw materials of special corundum mullite bricks for lime kilns, which is conducive to exerting better Refractory performance and chemical stability; the special corundum mullite bricks for lime kilns prepared by the present invention cooperate with other raw material groups under the action of aggregate to ensure high refractoriness and thermal shock resistance. At the same time, the bulk density is small and the structural strength is improved, which effectively reduces the cracking, head flaking, brick falling, kiln lining collapse and other phenomena of the kiln body; through preliminary research, it was found that rare earth element oxides can improve the toughness of refractory bricks. Adding rare earth elements to the raw materials of the special corundum mullite bricks for lime kilns of the present invention can reduce brittleness and stabilize structural performance. DETAILED DESCRIPTION

[0019] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments.

[0020] Therefore, the following detailed description of the embodiments of the present invention is not intended to limit the scope of the claimed invention, but rather merely represents selected embodiments of the present invention. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without creative effort are also within the scope of protection of the present invention.

[0021] It should be noted that, in the absence of conflict, the embodiments and features of the embodiments of the present invention can be combined with each other.

[0022] Example 1: A method for preparing a special corundum mullite brick for lime kiln, wherein the raw materials thereof include aggregate, silicon carbide, corundum, fused quartz, Guangxi white mud, aluminum dihydrogen phosphate, and rare earth elements; the aggregate is crushed from mullite blocks; the raw materials of the mullite blocks include ultrafine alumina powder, zirconium-containing silicon powder, andalusite, kyanite, and sillimanite; the present invention combines sillimanite, andalusite, and kyanite with ultrafine alumina powder and zirconium-containing silicon powder to make mullite, ensuring that sillimanite, andalusite, and kyanite can be transformed into mullite gridding at high temperature before being used as raw materials for special corundum mullite brick for lime kiln, thereby reducing the bulk density of the aggregate and making it have higher refractory and stability; the raw materials of sillimanite, andalusite, and kyanite are used to prepare mullite. Mullite blocks made from quartz as raw materials are crushed and added as aggregates to the raw materials of special corundum mullite bricks for lime kilns. They can cooperate with other raw materials to achieve better refractory performance and chemical stability. The special corundum mullite bricks for lime kilns prepared by the present invention cooperate with other raw materials under the action of aggregates to ensure high refractory performance and thermal shock resistance. At the same time, the bulk density is small and the structural strength is improved, effectively reducing the cracking, head flaking, brick falling, kiln lining collapse and other phenomena of the kiln body. According to previous studies, rare earth element oxides can improve the toughness of refractory bricks. Adding rare earth elements to the raw materials of the special corundum mullite bricks for lime kilns of the present invention can reduce brittleness and stabilize structural performance.

[0023] According to weight percentage, its raw materials include 50-65 parts of aggregate, 5-10 parts of silicon carbide, 45-55 parts of corundum, 40-45 parts of fused quartz, 20-30 parts of Guangxi white mud, 5-15 parts of aluminum dihydrogen phosphate and 0.5-1 part of rare earth elements;

[0024] According to weight percentage, the raw materials constituting the mullite block include 10 to 100 parts of ultrafine alumina powder, 10 to 100 parts of zirconium-containing silicon powder, 10 to 100 parts of andalusite, 10 to 100 parts of kyanite, and 10 to 100 parts of sillimanite;

[0025] The rare earth element is one or both of cerium oxide and yttrium oxide;

[0026] Prepared by the following steps:

[0027] 1) Prepare mullite blocks for later use;

[0028] 2) Crushing abrasive stones into aggregate;

[0029] 3) Mix the raw materials according to the proportion;

[0030] 4) Molding, drying and calcining;

[0031] The specific steps of step 1) are: mixing ultrafine alumina powder, zirconium-containing silicon powder, andalusite, kyanite, and sillimanite in proportion, vacuum extruding, block making, and calcining to obtain mullite blocks;

[0032] The calcination temperature is 1600° C. to 1750° C., and the calcination time is 1 hour to 10 hours.

[0033] Example 2: A method for preparing a special corundum mullite brick for lime kiln, wherein the raw materials thereof include aggregate, silicon carbide, corundum, fused quartz, Guangxi white mud, aluminum dihydrogen phosphate, and rare earth elements; the aggregate is crushed from mullite blocks; the raw materials of the mullite blocks include ultrafine alumina powder, zirconium-containing silicon powder, andalusite, kyanite, and sillimanite; the present invention combines sillimanite, andalusite, and kyanite with ultrafine alumina powder and zirconium-containing silicon powder to make mullite, ensuring that sillimanite, andalusite, and kyanite can be transformed into mullite gridding at high temperature before being used as raw materials for special corundum mullite brick for lime kiln, thereby reducing the bulk density of the aggregate and making it have higher refractory resistance and stability; the raw materials of sillimanite, andalusite, and kyanite are used to prepare mullite. Mullite blocks made from quartz as raw materials are crushed and added as aggregates to the raw materials of special corundum mullite bricks for lime kilns. They can cooperate with other raw materials to achieve better refractory performance and chemical stability. The special corundum mullite bricks for lime kilns prepared by the present invention cooperate with other raw materials under the action of aggregates to ensure high refractory performance and thermal shock resistance. At the same time, the bulk density is small and the structural strength is improved, effectively reducing the cracking, head flaking, brick falling, kiln lining collapse and other phenomena of the kiln body. According to previous studies, rare earth element oxides can improve the toughness of refractory bricks. Adding rare earth elements to the raw materials of the special corundum mullite bricks for lime kilns of the present invention can reduce brittleness and stabilize structural performance.

[0034] According to weight percentage, its raw materials include 50 parts of aggregate, 5 parts of silicon carbide, 45 parts of corundum, 40 parts of fused quartz, 20 parts of Guangxi white mud, 5 parts of aluminum dihydrogen phosphate and 0.5 parts of rare earth elements;

[0035] According to weight fraction, according to weight parts, the raw materials constituting the mullite block include 10 parts of ultrafine alumina powder, 10 parts of zirconium-containing silicon powder, 10 parts of andalusite, 10 parts of kyanite, and 10 parts of sillimanite;

[0036] The rare earth element is yttrium oxide;

[0037] Prepared by the following steps:

[0038] 1) Prepare mullite blocks for later use;

[0039] 2) Crushing abrasive stones into aggregate;

[0040] 3) Mix the raw materials according to the proportion;

[0041] 4) Molding, drying and calcining;

[0042] The specific steps of step 1) are: mixing ultrafine alumina powder, zirconium-containing silicon powder, andalusite, kyanite, and sillimanite in proportion, vacuum extruding, block making, and calcining to obtain mullite blocks;

[0043] The calcination temperature is 1600° C. to 1750° C., and the calcination time is 1 hour to 10 hours.

[0044] Example 3: A method for preparing a special corundum mullite brick for lime kiln, wherein the raw materials thereof include aggregate, silicon carbide, corundum, fused quartz, Guangxi white mud, aluminum dihydrogen phosphate, and rare earth elements; the aggregate is formed by crushing mullite blocks; the raw materials of the mullite blocks include ultrafine alumina powder, zirconium-containing silicon powder, andalusite, kyanite, and sillimanite; the present invention combines sillimanite, andalusite, and kyanite with ultrafine alumina powder and zirconium-containing silicon powder to make mullite, ensuring that sillimanite, andalusite, and kyanite can be transformed into mullite gridding at high temperature before being used as raw materials for special corundum mullite brick for lime kiln, thereby reducing the bulk density of the aggregate and making it have higher refractory and stability; the raw materials of sillimanite, andalusite, and kyanite are used to prepare mullite. Mullite blocks made from quartz as raw materials are crushed and added as aggregates to the raw materials of special corundum mullite bricks for lime kilns. They can cooperate with other raw materials to achieve better refractory performance and chemical stability. The special corundum mullite bricks for lime kilns prepared by the present invention cooperate with other raw materials under the action of aggregates to ensure high refractory performance and thermal shock resistance. At the same time, the bulk density is small and the structural strength is improved, effectively reducing the cracking, head flaking, brick falling, kiln lining collapse and other phenomena of the kiln body. According to previous studies, rare earth element oxides can improve the toughness of refractory bricks. Adding rare earth elements to the raw materials of the special corundum mullite bricks for lime kilns of the present invention can reduce brittleness and stabilize structural performance.

[0045] According to weight percentage, its raw materials include 65 parts of aggregate, 10 parts of silicon carbide, 55 parts of corundum, 45 parts of fused quartz, 30 parts of Guangxi white mud, 15 parts of aluminum dihydrogen phosphate and 1 part of rare earth elements;

[0046] According to weight fraction, according to weight parts, the constituent raw materials of the mullite block include 100 parts of ultrafine alumina powder, 100 parts of zirconium-containing silicon powder, 100 parts of andalusite, 100 parts of kyanite, and 100 parts of sillimanite;

[0047] The rare earth element is cerium oxide;

[0048] Prepared by the following steps:

[0049] 1) Prepare mullite blocks for later use;

[0050] 2) Crushing abrasive stones into aggregate;

[0051] 3) Mix the raw materials according to the proportion;

[0052] 4) Molding, drying and calcining;

[0053] The specific steps of step 1) are: mixing ultrafine alumina powder, zirconium-containing silicon powder, andalusite, kyanite, and sillimanite in proportion, vacuum extruding, block making, and calcining to obtain mullite blocks;

[0054] The calcination temperature is 1600° C. to 1750° C., and the calcination time is 1 hour to 10 hours.

[0055] Example 4: A method for preparing a special corundum mullite brick for lime kiln, wherein the raw materials thereof include aggregate, silicon carbide, corundum, fused quartz, Guangxi white mud, aluminum dihydrogen phosphate, and rare earth elements; the aggregate is crushed from mullite blocks; the raw materials of the mullite blocks include ultrafine alumina powder, zirconium-containing silicon powder, andalusite, kyanite, and sillimanite; the present invention combines sillimanite, andalusite, and kyanite with ultrafine alumina powder and zirconium-containing silicon powder to make mullite, ensuring that sillimanite, andalusite, and kyanite can be transformed into mullite gridding at high temperature before being used as raw materials for special corundum mullite brick for lime kiln, thereby reducing the bulk density of the aggregate and making it have higher fire resistance and stability; the raw materials of sillimanite, andalusite, and kyanite are used to prepare mullite. Mullite blocks made from quartz as raw materials are crushed and added as aggregates to the raw materials of special corundum mullite bricks for lime kilns. They can cooperate with other raw materials to achieve better refractory performance and chemical stability. The special corundum mullite bricks for lime kilns prepared by the present invention cooperate with other raw materials under the action of aggregates to ensure high refractory performance and thermal shock resistance. At the same time, the bulk density is small and the structural strength is improved, effectively reducing the cracking, head flaking, brick falling, kiln lining collapse and other phenomena of the kiln body. According to previous studies, rare earth element oxides can improve the toughness of refractory bricks. Adding rare earth elements to the raw materials of the special corundum mullite bricks for lime kilns of the present invention can reduce brittleness and stabilize structural performance.

[0056] According to weight percentage, its raw materials include 60 parts of aggregate, 8 parts of silicon carbide, 50 parts of corundum, 42 parts of fused quartz, 25 parts of Guangxi white mud, 10 parts of aluminum dihydrogen phosphate and 0.6 parts of rare earth elements;

[0057] According to weight fraction, according to weight parts, the raw materials constituting the mullite block include 50 parts of ultrafine alumina powder, 60 parts of zirconium-containing silicon powder, 15 parts of andalusite, 15 parts of kyanite, and 15 parts of sillimanite;

[0058] The rare earth elements are cerium oxide and yttrium oxide; the weight ratio of cerium oxide to yttrium oxide is 1:2;

[0059] Prepared by the following steps:

[0060] 1) Prepare mullite blocks for later use;

[0061] 2) Crushing abrasive stones into aggregate;

[0062] 3) Mix the raw materials according to the proportion;

[0063] 4) Molding, drying and calcining;

[0064] The specific steps of step 1) are: mixing ultrafine alumina powder, zirconium-containing silicon powder, andalusite, kyanite, and sillimanite in proportion, vacuum extruding, block making, and calcining to obtain mullite blocks;

[0065] The calcination temperature is 1600° C. to 1750° C., and the calcination time is 1 hour to 10 hours.

[0066] Comparative Example 1: Special corundum mullite bricks for lime kilns were prepared using the same preparation method as in Example 4, with the only difference being that ultrafine alumina powder, zirconium-containing silicon powder, andalusite, kyanite, and sillimanite were directly powdered and then added to silicon carbide, corundum, fused quartz, Guangxi white mud, aluminum dihydrogen phosphate, and rare earth elements to prepare special corundum mullite bricks for lime kilns.

[0067] Comparative Example 2: Special corundum mullite bricks for lime kiln were prepared by the same preparation method as in Example 4, except that the mullite blocks were made from ultrafine alumina powder and zirconium-containing silicon powder as raw materials.

[0068] Comparative Example 3: Special corundum mullite bricks for lime kiln were prepared by the same preparation method as in Example 4, except that the mullite blocks were made from ultrafine alumina powder, zirconium-containing silicon powder and andalusite.

[0069] Comparative Example 4: Special corundum mullite bricks for lime kiln were prepared by the same preparation method as in Example 4, except that the mullite blocks were made from ultrafine alumina powder, zirconium-containing silicon powder and kyanite as raw materials.

[0070] Comparative Example 5: Special corundum mullite bricks for lime kiln were prepared by the same preparation method as Example 4, except that the mullite blocks were made from ultrafine alumina powder, zirconium-containing silicon powder and sillimanite as raw materials.

[0071] Special corundum mullite bricks for lime kilns were prepared using the preparation methods of Examples 2 to 4, and their refractoriness, thermal shock resistance, and bulk density were tested. The bricks were compared with the special corundum mullite bricks for lime kilns prepared in Comparative Examples 1-5. The results are shown in the following table.

[0072] Table 1 Performance test results of special corundum mullite bricks for lime kiln

[0073]

[0074] Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments, or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for preparing special corundum mullite bricks for lime kiln, characterized by: Its raw materials include aggregate, silicon carbide, corundum, fused quartz, Guangxi white mud, aluminum dihydrogen phosphate, and rare earth oxides; the aggregate is crushed from mullite blocks; the raw materials of the mullite blocks include ultrafine alumina powder, zirconium-containing silicon powder, andalusite, kyanite, and sillimanite.

2. The method for preparing special corundum mullite bricks for lime kiln according to claim 1, wherein: In terms of weight fraction, its raw materials include 50-65 parts of aggregate, 5-10 parts of silicon carbide, 45-55 parts of corundum, 40-45 parts of fused quartz, 20-30 parts of Guangxi white mud, 5-15 parts of aluminum dihydrogen phosphate and 0.5-1 part of rare earth oxide.

3. The method for preparing the special corundum mullite brick for lime kiln according to claim 1, wherein: According to weight percentage, the raw materials constituting the mullite block include 10 to 100 parts of ultrafine alumina powder, 10 to 100 parts of zirconium-containing silicon powder, 10 to 100 parts of andalusite, 10 to 100 parts of kyanite, and 10 to 100 parts of sillimanite.

4. The method for preparing special corundum mullite bricks for lime kiln according to claim 1, wherein: The rare earth oxide is one or both of cerium oxide and yttrium oxide.

5. The method for preparing special corundum mullite bricks for lime kiln according to claim 1, characterized in that: Prepared by the following steps: 1) Prepare mullite blocks for later use; 2) Crushing abrasive stones into aggregate; 3) Mix the raw materials according to the proportion; 4) Molding, drying and calcining.

6. The method for preparing special corundum mullite bricks for lime kiln according to claim 5, characterized in that: The specific steps of step 1) are: mixing ultrafine alumina powder, zirconium-containing silicon powder, andalusite, kyanite, and sillimanite in proportion, vacuum extruding, block making, and calcining to obtain mullite blocks.

7. The method for preparing special corundum mullite bricks for lime kiln according to claim 6, characterized in that: The calcination temperature is 1600° C. to 1750° C., and the calcination time is 1 hour to 10 hours.

8. A special corundum mullite brick for lime kiln, characterized by: The special corundum mullite brick is prepared by the preparation method of any one of claims 1 to 7 for special lime kiln use.

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