Multi-performance fused cast zirconia-corundum fused brick and preparation method thereof

Abstract

The invention discloses a multi-performance fused cast zirconia-corundum fused brick and a preparation method thereof. The fused brick is prepared by adding a modified material on the basis of fused brick raw materials. The modified material comprises chromium powder, molybdenum powder and tungsten powder according to the mass ratio of 1: 2: 2. The chromium-molybdenum-tungsten powder is added into the zirconia-corundum brick and is uniformly distributed in the zirconia-corundum brick, and the combination of chromium, molybdenum and tungsten forms a better anti-oxidation effect, so that the hardness and physical and chemical erosion resistance of the zirconia-corundum brick are greatly improved. The molybdenum-chromium-tungsten powder is combined with the refractory material, so that the viscosity of the glass phase is increased, the precipitation temperature of the glass phase is increased, the precipitation gap of the glass phase is smaller, and the precipitation amount of the glass phase of the electrically-fused brick is greatly reduced. Due to the addition of the molybdenum-chromium-tungsten powder, the meltability of the product is improved, and the thermal shock resistance is greatly improved. According to the material flowing nozzle brick for the tube drawing glass kiln, four material flowing nozzle bricks are changed from one kiln period before to one material flowing nozzle brick for completing the service life of the whole kiln period after improvement, and a decisive effect on prolonging the service life of the glass kiln is achieved.

Description

Technical Field

[0001] The present invention relates to a multi-performance fused cast zirconia corundum electrofused brick and a preparation method thereof, belonging to the technical field of electrofused bricks. Background Technique

[0002] Fused cast zirconia corundum brick (AZS) is the main material for lining glass furnaces. In China, the introduction of fused cast zirconia corundum brick dates back to the 1960s. By 1989, China was able to produce high-quality 33#, 36# and 41# fused cast AZS bricks by the oxidation method, which were used in different positions of glass furnaces according to process design. Different glass properties and models have specific requirements for aspects such as the design of glass furnaces, the selection of refractory materials, operation and maintenance, environmental protection and energy conservation, and temperature control to ensure the quality of glass products and the efficient and stable operation of the furnaces. These design types reflect the diversity and complexity of glass furnace design, and each design has its specific application scenarios and advantages. However, even with a scientific and reasonable design, it is still inevitable to avoid the deficiencies brought about by the inherent characteristics of electrofused bricks, resulting in the damage of electrofused bricks.

[0003] In a glass furnace, the parts where zirconia corundum electrofused bricks are easily damaged are as follows:

[0004] 1. The sidewall of the melting section: The part in direct contact with the glass liquid is subjected to high temperature, chemical erosion caused by the glass liquid, and mechanical and physical erosion caused by the flow.

[0005] 2. The crown (including the arch angle): These parts are at a working temperature of 1600 °C. The refractory materials used should be able to withstand high temperature, load, as well as the erosion of alkali vapor and batch materials. Chemical erosion caused by the high-temperature chemical reaction of batch materials and alkali vapor with refractory materials, as well as the crystal form transformation and structural densification change caused by phase migration and temperature are the main reasons for the damage of crown bricks. At the same time, the precipitation of the glass phase in the refractory materials into the glass affects the glass quality.

[0006] 3. Key parts such as the throat, the dam in the furnace, the bottom bubbling of the tank, and the all-electric melting furnace: Due to their key nature, these parts have extremely high requirements for the erosion resistance of refractory materials.

[0007] 4. The sidewall at the corner of the neck in the clarification section: These parts are the places where zirconia corundum electrofused bricks are most easily damaged due to direct contact with high-temperature glass liquid, chemical erosion, physical erosion, and thermal stress. During operation, slight seepage may occur, and it is necessary to monitor and handle it in time to avoid the deterioration of the furnace seepage accident.

[0008] 5. The crown of the charging port and the vicinity of the charging port: Since the temperature fluctuates greatly here, it is easy to cause the electrofused brick to burst, so there are requirements for the thermal shock resistance of the electrofused brick. However, the thermal shock resistance is a defect of the inherent characteristics of the electrofused brick. Therefore, it has high requirements for the skills of glass workers.

[0009] 6. High borosilicate glass and glass melts containing boric acid, phosphoric acid, fluorine, aluminum, and barium compounds have a severe erosion effect on refractory materials. Intense glass melt convection and an unstable liquid surface will wash away the protective layer, accelerating corrosion and reducing the service life of glass furnaces.

[0010] Therefore, higher requirements are put forward for the quality of fused zirconia corundum bricks, specifically manifested as follows: 1. Increase the thermal shock resistance of fused zirconia corundum bricks to avoid cracking at positions with large temperature fluctuations; 2. Increase the viscosity of the glass phase, reduce the precipitation amount of the glass phase, ensure the glass quality while increasing the high-temperature erosion resistance of the fused bricks; 3. Increase the bulk density of the fused bricks, improve the ability of the fused bricks to resist the dynamic erosion of glass melts, thereby extending the service time of glass furnaces. Summary of the Invention

[0011] Aiming at the deficiencies of the prior art, the purpose of the present invention is to provide a multi-performance fused zirconia corundum brick and its preparation method, which can effectively improve the physical erosion resistance, chemical erosion resistance, high-temperature erosion resistance, and thermal shock resistance of the fused bricks.

[0012] To achieve the above purpose, the technical solution of the present invention is to provide a modified material for fused zirconia corundum bricks, including chromium powder, molybdenum powder, and tungsten powder, and the mass ratio of the three is 1:2:2.

[0013] Furthermore, the chromium content in the chromium powder is not less than 99%, the molybdenum content in the molybdenum powder is not less than 99%, and the tungsten content in the tungsten powder is not less than 99%.

[0014] Furthermore, the particle size of the chromium powder is 20 - 50 mesh, the particle size of the molybdenum powder is not greater than 30 microns, and the particle size of the tungsten powder is 10 - 30 microns.

[0015] On the other hand, the technical solution of the present invention is to provide a multi-performance fused zirconia corundum brick, including fused brick raw materials and the above-mentioned modified material, and the mass ratio of the two is 97:3.

[0016] On the other hand, the technical solution of the present invention is to provide a preparation method for the above-mentioned multi-performance fused zirconia corundum brick, including the following steps:

[0017] (1) Weigh chromium powder, molybdenum powder, and tungsten powder according to the mass ratio, mix and stir evenly to obtain the modified material;

[0018] (2) Weigh zircon sand and alumina powder according to the raw material ratio of different types of fused bricks, mix and stir evenly to obtain the fused brick raw materials;

[0019] (3) Add the modified material to the fused brick raw materials and stir evenly again.

[0020] (4) Charge, melt, cast, and anneal according to conventional methods.

[0021] Beneficial effects:

[0022] In the present invention, chromium-molybdenum-tungsten powder is added to the zircon corundum brick and evenly distributed therein. The combination of chromium, molybdenum, and tungsten forms a better antioxidant effect, greatly improving the hardness and the ability to resist physical and chemical erosion of the zircon corundum brick. The combination of molybdenum-chromium-tungsten powder and the refractory increases the viscosity of the glass phase, raises the precipitation temperature of the glass phase, and makes the precipitation gaps of the glass phase smaller. Compared with the glass phase precipitation amount (1500°C × 4h / 0.3%) of the fused cast brick without adding the modifier, the glass phase precipitation amount of the fused cast brick of the present invention is greatly reduced (1500°C × 4h / 0.22%). In addition, due to the addition of molybdenum-chromium-tungsten powder, the melting and solidifying properties of the product are improved, that is, the adhesiveness or integrity of each component is more consistent, and the thermal shock resistance is greatly enhanced. The thermal shock resistance test shows that: the experimental results from room temperature to 1500°C can reach up to three times at most. For the flow nozzle brick used in the drawing glass furnace, the number of replacements per kiln period has changed from four to one after improvement, which plays a decisive role in extending the service life of the glass furnace. Specific embodiments

[0023] The following further elaborates on the specific embodiments of the present invention in conjunction with the examples.

[0024] The chromium content in the chromium powder is not less than 99%, the molybdenum content in the molybdenum powder is not less than 99%, and the tungsten content in the tungsten powder is not less than 99%.

[0025] The particle size of the chromium powder is 20 - 50 mesh, the particle size of the molybdenum powder is not more than 30 microns, and the particle size of the tungsten powder is 10 - 30 microns.

[0026] Example 1

[0027] A multi-performance fused cast zircon corundum brick (41#) includes fused cast brick raw materials and a modifier, and the mass ratio of the two is 97:3; the fused cast brick raw materials include zircon sand and alumina powder, and the mass ratio of the two is 60:40; the modifier includes chromium powder, molybdenum powder, and tungsten powder, and the mass ratio of the three is 1:2:2.

[0028] Its preparation method is as follows:

[0029] (1) Weigh chromium powder, molybdenum powder, and tungsten powder according to the mass ratio, mix and stir evenly to obtain the modifier;

[0030] (2) Weigh zircon sand and alumina powder according to the mass ratio, mix and stir evenly to obtain the fused cast brick raw materials;

[0031] (3) Add the modifier to the fused cast brick raw materials and stir evenly again;

[0032] (4) Add the mixture from step (3) into an electric arc furnace, melt it by conventional method, cast, and anneal. Nitrogen gas is continuously blown throughout the melting process (pressure 7 Mpa, flow rate 15 m 3 / h). The purpose of blowing nitrogen gas is to prevent the modified material from being oxidized, and nitrogen gas is not blown after melting.

[0033] The melting weight of the 41# shrinkage-free cast fused magnesia produced in this example is 4.28, which is much higher than the national standard requirement: 3.95 (41#).

[0034] Example 2

[0035] A multi-property fused zirconia corundum fused magnesia brick (36#) comprises fused magnesia raw materials and a modified material, and the mass ratio of the two is 97:3; the fused magnesia raw materials include zircon sand and alumina powder, and the mass ratio of the two is 55:43; the modified material includes chromium powder, molybdenum powder and tungsten powder, and the mass ratio of the three is 1:2:2.

[0036] Its preparation method is as follows:

[0037] (1) Weigh chromium powder, molybdenum powder and tungsten powder according to the mass ratio, mix and stir evenly to obtain the modified material;

[0038] (2) Weigh zircon sand and alumina powder according to the mass ratio, mix and stir evenly to obtain the fused magnesia raw materials;

[0039] (3) Add the modified material into the fused magnesia raw materials and stir evenly again;

[0040] (4) Add the mixture from step (3) into an electric arc furnace, melt it by conventional method, cast, and anneal. Nitrogen gas is continuously blown throughout the melting process (pressure 7 Mpa, flow rate 15 m 3 / h). The purpose of blowing nitrogen gas is to prevent the modified material from being oxidized, and nitrogen gas is not blown after melting.

[0041] The melting weight of the 36# shrinkage-free cast fused magnesia produced in this example is 4.10, which is much higher than the national standard requirement: 3.85 (36#).

[0042] Example 3

[0043] A multi-property fused zirconia corundum fused magnesia brick (33#) comprises fused magnesia raw materials and a modified material, and the mass ratio of the two is 97:3; the fused magnesia raw materials include zircon sand and alumina powder, and the mass ratio of the two is 50:47; the modified material includes chromium powder, molybdenum powder and tungsten powder, and the mass ratio of the three is 1:2:2.

[0044] Its preparation method is as follows:

[0045] (1) Weigh chromium powder, molybdenum powder and tungsten powder according to the mass ratio, mix and stir evenly to obtain the modified material;

[0046] (2) Weigh zircon sand and alumina powder according to the mass ratio, mix and stir evenly to obtain the raw materials for fused cast bricks.

[0047] (3) Add the modifying material to the raw materials for fused cast bricks and stir evenly again.

[0048] (4) Add the mixture in step (3) to an electric arc furnace, melt it by a conventional method, cast, and anneal. Nitrogen gas is continuously blown during the entire melting process (pressure 7 Mpa, flow rate 15 m 3 / h). The purpose of blowing nitrogen gas is to prevent the modifying material from being oxidized, and nitrogen gas is not blown after melting.

[0049] The fusion weight of the 33# ordinary cast fused cast brick produced in this example is 3.53, which is higher than the specified value of 3.45 (33#) in the national standard. Performance detection:

[0050] Take the fused cast zircon corundum fused cast brick (41#) as the experimental sample. Add modifying materials with different formulations (the mass ratio of the raw materials for fused cast bricks to the modifying material is 97:3) to the raw materials for fused cast bricks (the mass ratio of zircon sand to alumina powder is 60:40). The specific formulations of the modifying materials are as follows. Detect and compare the fusion weight, thermal shock resistance, erosion resistance, and initial crystallization temperature of the glass phase of the fused cast bricks produced by the present invention and the modifying materials with different formulations. The results are shown in Table 1.

[0051] Thermal shock resistance test method: Place a cube sample block with a side length of 100 mm in a muffle furnace, heat it to 1500 °C, take it out, and cool it to room temperature. Observe the situation of the sample block. If it does not crack, it is counted as one time.

[0052] The modifying material for Comparative Example 1 is (mass ratio): chromium powder: molybdenum powder = 1:2

[0053] The modifying material for Comparative Example 2 is (mass ratio): chromium powder: tungsten powder = 1:2

[0054] The modifying material for Comparative Example 3 is (mass ratio): molybdenum powder: tungsten powder = 1:1

[0055] The modifying material for Comparative Example 4 is (mass ratio): nickel powder: molybdenum powder: tungsten powder = 1:2:2

[0056] The modifying material for Comparative Example 5 is (mass ratio): chromium powder: tantalum powder: iron powder = 1:2:2

[0057] The modifying material for Comparative Example 6 is (mass ratio): no modifying material is added

[0058] Table 1

[0059]

[0060]

[0061] 1. As can be seen from Table 1, the fusion weight of the No. 41 shrinkage-free casting fused cast brick produced by the present invention is 4.28, which is much higher than that of the fused cast bricks added with other formula modification materials. The increase in fusion weight represents an increase in the density (bulk density), indicating that the fused cast zirconia corundum fused cast brick produced by the present invention is more resistant to the dynamic erosion of molten glass.

[0062] 2. As can be seen from Table 1, the number of experiments of the fused cast bricks of Comparative Examples 1-3 from room temperature to 1500 °C is 1-2 times. Due to the weak binding ability between the modification material and the raw materials of the fused cast brick in Comparative Examples 4 and 5, it is difficult to control cracks and it is difficult to form. The number of experiments of the fused cast brick of Comparative Example 6 without adding modification material from room temperature to 1500 °C is 0 times, while the number of experiments of the fused cast brick produced by the present invention from room temperature to 1500 °C can reach up to 3 times at most, proving that the fused cast brick produced by the present invention has good thermal shock resistance.

[0063] 3. As can be seen from Table 1, the erosion rate of the fused cast bricks of Comparative Examples 1-3 and 6 against molten glass under static conditions is greater than 1.2 mm / d, while the erosion rate of the fused cast brick of the present invention against molten glass under static conditions is as low as 1.1 mm / d, proving that the erosion resistance of the fused cast brick added with the modification material of the present invention under static conditions is greatly improved.

[0064] 4. As can be seen from Table 1, the primary crystallization temperature of the glass phase of the fused cast brick of the present invention is significantly higher than that of the fused cast bricks of Comparative Examples 1-3 and 6, which will greatly reduce the precipitation amount of the glass phase and increase the high-temperature erosion resistance of the fused cast brick while ensuring the glass quality.

[0065] Service life test:

[0066] For the flow nozzle brick used in the drawing tube glass furnace, when using the No. 33 fused cast brick without adding modification material as the flow nozzle brick, four flow nozzle bricks need to be replaced in one kiln period. While when using the No. 33 fused cast brick added with chromium-molybdenum-tungsten powder of the present invention as the flow nozzle brick, under the same conditions, one flow nozzle brick can be used for one kiln period without replacement, which greatly extends the service life of the glass furnace.

Claims

1. A modified material for fused zirconia corundum electrofused bricks, characterized in that, It includes chromium powder, molybdenum powder and tungsten powder, and the mass ratio of the three is 1:2:

2.

2. The modified material according to claim 1, wherein The chromium content in the chromium powder is not less than 99%, the molybdenum content in the molybdenum powder is not less than 99%, and the tungsten content in the tungsten powder is not less than 99%.

3. The modified material according to claim 1, characterized in that, The particle size of the chromium powder is 20 - 50 mesh, the particle size of the molybdenum powder is not more than 30 microns, and the particle size of the tungsten powder is 10 - 30 microns.

4. A multi-performance fused zirconia corundum electrofused brick, characterized in that, It includes electrofused brick raw materials and the modified material described in any one of claims 1 - 3, and the mass ratio of the two is 97:

3.

5. A preparation method of the multi-property fused zirconia corundum electrofused brick as described in claim 4, characterized in that, It includes the following steps: (1) Weigh chromium powder, molybdenum powder and tungsten powder according to the mass ratio, mix and stir evenly to obtain the modified material; (2) Weigh zircon sand and alumina powder according to the raw material ratio of different types of electrofused bricks, mix and stir evenly to obtain the electrofused brick raw materials; (3) Add the modified material to the electrofused brick raw materials and stir evenly again; (4) Carry out feeding, melting, casting and annealing according to the conventional method.

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