Refractory material for waste incineration fly ash high-temperature melting furnace and preparation method of refractory material

Abstract

The invention belongs to the field of refractory materials. The invention provides a refractory material for a waste incineration fly ash high-temperature melting furnace, which comprises the following components in percentage by mass: 30-36% of zirconium oxide, 11-16% of silicon dioxide, 1.15-1.5% of sodium oxide and potassium oxide, 2-3% of yttrium oxide, 0.8-1.2% of titanium oxide and the balance of aluminum oxide, the invention further provides a preparation method of the refractory material for the waste incineration fly ash high-temperature melting furnace. The refractory material for the high-temperature melting furnace for the waste incineration fly ash has more excellent erosion resistance, the erosion speed of the waste incineration fly ash containing elements such as chlorine and sulfur to a lining material of the melting furnace during high-temperature melting is remarkably reduced, and the service time of the high-temperature melting furnace for the fly ash is prolonged.

Description

Technical Field

[0001] The invention belongs to the field of refractory materials, and in particular relates to a refractory material for a fly ash high-temperature melting furnace and a preparation method thereof. Background Art

[0002] Waste incineration is a common method of urban waste disposal, but the incineration process produces a large amount of fly ash, which contains a variety of harmful substances, such as heavy metals and dioxins, posing potential risks to the environment and human health.

[0003] High-temperature melting is an effective method for treating fly ash from waste incineration. It can reduce the content of harmful substances and solidify the fly ash to prevent further pollution. However, fly ash contains elements such as chlorine and sulfur, which volatilize at high temperatures and are highly corrosive to the lining materials of the melting furnace, affecting the overall service life of the kiln.

[0004] The conventional fused-cast zirconium corundum refractory materials in the prior art have poor corrosion resistance to fly ash containing elements such as chlorine and sulfur when melted at high temperatures, and cannot meet the use requirements when the front end clearly understands the characteristics of fly ash containing elements such as chlorine and sulfur.

[0005] CN115010485A discloses a refractory material for a melting furnace, which is made by mixing silica, chromium oxide, fused magnesia, a skeleton of yttrium oxide, a zirconium oxide matrix and a binder. The material has the functions of resisting erosion by fly ash and slag and reducing cracks in the refractory material. The preparation method adopts a pressing and sintering process. During the preparation process, ultra-high pressure (200-250Mpa) is required to press the blank, the process conditions are relatively high, and the process is relatively complicated.

[0006] The present invention provides different technical ideas, adopts different formulas and preparation methods. The refractory material for the high-temperature melting furnace of waste incineration fly ash of the present invention has more excellent corrosion resistance. The refractory material significantly reduces the erosion rate of the melting furnace lining material during high-temperature melting of waste incineration fly ash containing elements such as chlorine and sulfur, thereby extending the service life of the fly ash high-temperature melting furnace. Summary of the invention

[0007] In order to solve the above-mentioned problems of the prior art, the present invention provides a refractory material for a high-temperature melting furnace of waste incineration fly ash and a preparation method thereof. The refractory material has better density and corrosion resistance, improves the initial precipitation temperature of the glass phase, and significantly slows down the erosion rate of the melting furnace lining material during high-temperature melting of waste incineration fly ash containing elements such as chlorine and sulfur. The amount of glass phase seepage is significantly reduced, and the probability of oxide precipitation is greatly reduced. It has excellent high-temperature structural stability and extends the service life of the high-temperature melting furnace. The raw material components are melted and mixed at high temperature, the components have good bonding properties, and have better homogeneity.

[0008] The object of the present invention is to provide a refractory material for a high-temperature melting furnace of waste incineration fly ash, comprising the following components in percentage by mass: 30-36% zirconium oxide, 11-16% silicon dioxide, 1.15-1.5% by mass of the sum of the contents of sodium oxide and potassium oxide, 2-3% yttrium oxide, 0.8-1.2% titanium oxide, and the balance being aluminum oxide.

[0009] Yttrium oxide and titanium oxide are introduced into the raw materials of the present invention to improve the corrosion resistance and thermal stability of the finished refractory material; sodium oxide and potassium oxide are introduced to play a fluxing role in the production process to increase the density and uniformity of the molten material product.

[0010] In the refractory material, the mass ratio of the sodium oxide to the potassium oxide is 7-9:1, and the mass ratio of the silicon dioxide to the sum of the sodium oxide and the potassium oxide is 9-10:1.

[0011] The above ratio is a preferred fluxing ratio. The content of sodium oxide and potassium oxide should not be too high. Too high a content will correspondingly affect the high temperature resistance and slag resistance of the refractory material.

[0012] The total amount of impurities in the refractory material of the present invention is less than 1%.

[0013] When the impurity content is higher than 1%, the high temperature resistance of the prepared refractory material will be reduced, and pores may be generated in the refractory material, reducing the slag resistance and corrosion resistance.

[0014] By controlling the distribution ratio of each group and the synergistic effect between the components, the refractory material of the present invention has better density and corrosion resistance, the initial precipitation temperature of the glass phase is increased, the glass phase seepage is significantly reduced, the high-temperature structural stability is significantly improved, and the erosion rate of the material during high-temperature melting of fly ash containing elements such as chlorine and sulfur is significantly slowed down, thereby extending the service life of the melting furnace and reducing production energy consumption.

[0015] Furthermore, the surface of the refractory material also has an yttrium oxide coating with a coating thickness of 100-150 μm.

[0016] The present invention also aims to provide a method for preparing a refractory material for a high-temperature melting furnace for waste incineration fly ash, comprising the following steps:

[0017] (1) Raw material preparation: weigh zirconium oxide, silicon dioxide, sodium oxide, potassium oxide, yttrium oxide, titanium oxide, and titanium dioxide according to the above ratio and mix them evenly;

[0018] (2) Mold group preparation: making sand mold group;

[0019] (3) Raw material melting: The raw materials mixed in step (1) are melted in an electric arc furnace, and an oxygen blowing process is performed during the melting process. The temperature in the furnace is 2600-2700° C. and the constant temperature is controlled for 25-35 minutes;

[0020] (4) Casting: After melting is completed, the temperature in the arc furnace is reduced to 1900-2100°C, and the molten liquid is cast into the mold assembly;

[0021] (5) Insulation annealing: After casting, annealing and cooling are carried out in an insulation furnace. The cooling rate is: when the temperature is greater than 1200°C, the cooling rate is 15-25°C / h; when the temperature drops to 1200-800°C, the cooling rate is 10-15°C / h; when the temperature drops to 800-200°C, the cooling rate is 35-60°C / h; when the temperature drops below 200°C, it is naturally cooled to less than or equal to 50°C, and the refractory material made in the mold group is taken out.

[0022] The raw material components of the present invention are melted and mixed at high temperature, and the components have good bonding and better homogeneity; the process does not require ultra-high pressure conditions, and the process is not complicated. Through the synergistic effect of multiple factors of the raw material components and the preparation process, the corrosion resistance of the prepared refractory material is significantly improved.

[0023] After the medium-sized group is manufactured in step (2) of the preparation method of the present invention, a yttrium oxide coating is applied on the casting surface, and the coating thickness is 400-450 μm. After the yttrium oxide coating is applied on the casting surface according to the above steps, the refractory material surface has a yttrium oxide coating, and the coating thickness is 100-150 μm.

[0024] The present invention introduces yttria oxide coating into the mold group and utilizes high temperature coating during casting to improve the corrosion resistance and thermal shock resistance of the refractory surface, enhance the stability of the material, greatly reduce the probability of cracks and oxide precipitation during high-temperature use, and increase the service life of the material.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] (1) The present invention adjusts the composition system of the refractory material, introduces yttrium oxide and titanium oxide, significantly improves the thermal stability and corrosion resistance of the refractory material, and introduces sodium oxide and potassium oxide to play a fluxing role in the production process, thereby increasing the density and uniformity of the molten material product;

[0027] (2) By controlling the distribution ratio of each component and the synergistic effect between the components, the initial precipitation temperature of the glass phase is increased, the amount of glass phase seepage is significantly reduced, the erosion rate of the material caused by the high-temperature melting of fly ash containing elements such as chlorine and sulfur is significantly slowed down, and the high-temperature structural stability is significantly improved;

[0028] (3) In the process of the present invention, the raw material components are melted and mixed at high temperature, and the bonding between the components is good, with better homogeneity;

[0029] (4) By adding yttrium oxide coating to the mold assembly and then performing high-temperature casting and coating, a uniform and stable yttrium oxide coating is formed on the surface of the refractory material, thereby improving the stability and service life of the material;

[0030] (5) The method adopted by the present invention has wide applicability and significantly improves the performance of refractory materials. DETAILED DESCRIPTION

[0031] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0032] Preparation of refractory materials for high temperature melting furnace of waste incineration fly ash

[0033] Example 1

[0034] (1) Raw material preparation: weighed by mass percentage, 31% zirconium oxide, 48% aluminum oxide, 15% silicon dioxide, 3% yttrium oxide, 0.8% titanium dioxide, 2.2% sodium oxide and potassium oxide and other metal oxide impurities, the content of other metal oxide impurities is less than 1%, the mass ratio of sodium oxide to potassium oxide is 8:1, and the mass ratio of silicon dioxide to the sum of sodium oxide and potassium oxide is 9.5:1. The total amount of impurities in the refractory material of the present invention is less than 1%.

[0035] Zircon, zirconium oxide, corundum powder, sodium carbonate, potassium carbonate, quartz sand, yttrium oxide, titanium dioxide, etc. can be selected as sources of the above components.

[0036] Sodium oxide and potassium oxide play a role in fluxing in the melting preparation process, increasing the density and uniformity of the molten product. The content of sodium oxide and potassium oxide should not be too high. Too high a content will correspondingly affect the high temperature resistance and slag resistance of the refractory. If the impurity content is higher than 1%, the high temperature resistance of the prepared refractory will be reduced, and pores may be generated in the refractory, reducing the slag resistance and erosion resistance.

[0037] (2) Mold group preparation: After mixing the silica sand raw materials, a sand mold group is made according to the size of the refractory material. After the mold group is made, an yttrium oxide coating is applied to the casting surface with a coating thickness of 410 μm.

[0038] (3) Raw material melting: The mixed raw materials are melted in an electric arc furnace. The temperature in the furnace reaches 2600-2700°C and the constant temperature is controlled for 30 minutes to allow the raw materials to be completely and evenly melted to form a melt. Oxygen blowing is carried out during the melting process.

[0039] (4) Casting: After melting is completed, the temperature in the electric arc furnace is controlled to drop to 2000°C and the molten liquid is cast into the mold assembly.

[0040] (5) Insulation annealing: After casting, annealing and cooling are carried out in an insulation furnace, and the temperature is uniformly lowered. The cooling rate is as follows: when the temperature is greater than 1200°C, the cooling rate is controlled at 20°C / h; when the temperature is between 1200 and 800°C, the cooling rate is controlled at 10°C / h; when the temperature is between 800 and 200°C, the cooling rate is controlled at 40°C / h; when the temperature is below 200°C, the refractory product is naturally cooled to 50°C and taken out of the mold group. Since the yttrium oxide coating is applied to the casting surface in step (2), the refractory surface has an yttrium oxide coating with a thickness of 100-150 μm.

[0041] Example 2

[0042] (1) Raw material preparation: weighed by mass percentage, 33% zirconium oxide, 47.5% aluminum oxide, 14% silicon dioxide, 2.5% yttrium oxide, 0.8% titanium dioxide, 2.2% sodium oxide + potassium oxide and other metal oxide impurities, the content of other metal oxide impurities is less than 1%, the mass ratio of sodium oxide to potassium oxide is 8:1, and the mass ratio of silicon dioxide to the sum of sodium oxide and potassium oxide is 9.5:1. The total amount of impurities in the refractory material of the present invention is less than 1%.

[0043] (2) Mold group preparation: After mixing the silica sand raw materials, a sand mold group is made according to the size of the refractory material. After the mold group is made, an yttrium oxide coating is coated on the casting surface with a coating thickness of 430 μm.

[0044] (3) Raw material melting: The mixed raw materials are melted in an electric arc furnace. The temperature in the furnace reaches 2600-2700°C and the constant temperature is controlled for 30 minutes to allow the raw materials to be completely and evenly melted to form a melt. Oxygen blowing is carried out during the melting process.

[0045] (4) Casting: After melting is completed, the temperature in the electric arc furnace is controlled to drop to 2000°C and the molten liquid is cast into the mold assembly.

[0046] (5) Insulation annealing: After casting, annealing and cooling are carried out in an insulation furnace, and the temperature is uniformly lowered. The cooling rate is as follows: when the temperature is greater than 1200°C, the cooling rate is controlled at 20°C / h; when the temperature is between 1200 and 800°C, the cooling rate is controlled at 10°C / h; when the temperature is between 800 and 200°C, the cooling rate is controlled at 40°C / h; when the temperature is below 200°C, the refractory is naturally cooled to 50°C and the product made in the mold group is taken out. Since the yttrium oxide coating is applied to the casting surface in step (2), the refractory surface has an yttrium oxide coating with a thickness of 100-150 μm.

[0047] Example 3

[0048] (1) Raw material preparation: weighed by mass percentage, 36% zirconium oxide, 46% aluminum oxide, 13% silicon dioxide, 2% yttrium oxide, 0.8% titanium dioxide, 2.2% sodium oxide + potassium oxide and other metal oxide impurities, the content of other metal oxide impurities is less than 1%, the mass ratio of sodium oxide to potassium oxide is 8:1, and the mass ratio of silicon dioxide to the sum of sodium oxide and potassium oxide is 9.5:1. The total amount of impurities in the refractory material of the present invention is less than 1%.

[0049] (2) Mold group preparation: After mixing the silica sand raw materials, a sand mold group is made according to the size of the refractory material. After the mold group is made, an yttrium oxide coating is coated on the casting surface with a coating thickness of 450 μm.

[0050] (3) Raw material melting: The mixed raw materials are melted in an electric arc furnace. The temperature in the furnace reaches 2600-2700°C and the constant temperature is controlled for 30 minutes to allow the raw materials to be completely and evenly melted to form a melt. Oxygen blowing is carried out during the melting process.

[0051] (4) Casting: After melting is completed, the temperature in the electric arc furnace is controlled to drop to 2000°C and the molten liquid is cast into the mold assembly.

[0052] (5) Insulation annealing: After casting, annealing and cooling are carried out in an insulation furnace, and the temperature is uniformly lowered. The cooling rate is as follows: when the temperature is greater than 1200°C, the cooling rate is controlled at 20°C / h; when the temperature is between 1200 and 800°C, the cooling rate is controlled at 10°C / h; when the temperature is between 800 and 200°C, the cooling rate is controlled at 40°C / h; when the temperature is below 200°C, the refractory product is naturally cooled to 50°C and taken out of the mold group. Since the yttrium oxide coating is applied to the casting surface in step (2), the refractory surface has an yttrium oxide coating with a thickness of 100-150 μm.

[0053] Preparation of ordinary fused-cast zirconium corundum refractory

[0054] Comparative Example 1-2

[0055] The common fused-cast zirconium corundum refractory material has the following components: 32-36% zirconium oxide, 47-49% aluminum oxide, 14-16% silicon dioxide, and the rest are other metal oxides and impurities. The components and their mass percentages of comparative example 1 are 32.5% zirconium oxide, 48.8% aluminum oxide, 14.9% silicon dioxide, 1.6% sodium oxide, and 2.2% other metal oxides and impurities; the components and their mass percentages of comparative example 2 are 33.4% zirconium oxide, 47.5% aluminum oxide, 15.5% silicon dioxide, 1.5% sodium oxide, and 2.1% other metal oxides and impurities.

[0056] Performance test of refractory materials prepared in Examples 1-3 and refractory materials prepared in Comparative Examples 1-2

[0057] Corrosion resistance test comparison

[0058] According to the standard "Test Method for Static Resistance of Refractory Materials for Glass Melting Furnaces to Glass Liquid Erosion" (JC-T806-2013), the test method is to convert the 36-hour erosion data of fly ash melt from the incineration of domestic waste to 24-hour erosion data at a constant temperature of 1500°C. Each group of test data is obtained by averaging 4 samples.

[0059] Table 1 is a test data table of the corrosion resistance test of the refractory materials for high-temperature melting furnace of waste incineration fly ash prepared in Examples 1-3 and the ordinary fused-cast zirconium corundum refractory materials prepared in Control Examples 1-2. The two directions of comparison are the corrosion below the molten liquid surface and the corrosion at the liquid surface line (i.e., the gas-liquid-solid three-phase junction).

[0060] Table 1 Corrosion resistance test data

[0061]

[0062]

[0063] As can be seen from Table 1, compared with the ordinary fused-cast zirconium corundum refractory of the control example, the erosion rate of the fly ash melt at the three-phase interface and the erosion rate of the fly ash melt at 1 / 2 below the liquid are significantly reduced, which can extend the service life of the refractory.

[0064] Comparison of glass phase initial precipitation temperature and glass exudation amount

[0065] The comparison of glass phase initial precipitation temperature and glass seepage amount (1500℃, 4h) was carried out according to "Fused-cast zirconium corundum refractory products for glass melting furnaces" (JC493-2015).

[0066] Table 2 is a test data table of the glass phase initial precipitation temperature and glass seepage amount of the refractory materials for high-temperature melting furnaces of waste incineration fly ash prepared in Examples 1-3 and the ordinary fused-cast zirconium corundum refractory materials in Control Examples 1-2.

[0067] Table 2 Glass phase initial precipitation temperature and glass exudation data

[0068] Glass phase initial precipitation temperature / ℃ Glass phase exudation (1500℃, 4h) / % Example 1 1480 0.4 Example 2 1510 0.3 Example 3 1490 0.5 Comparative Example 1 1410 2.1 Comparative Example 2 1410 1.8

[0069] It can be seen from Table 2 that compared with the common fused-cast zirconium corundum refractory of the control example, the glass phase initial precipitation temperature of the refractory of the present invention is significantly increased, and the glass phase seepage amount is significantly reduced.

[0070] Therefore, the composition system of the refractory material of the present invention has an obvious anti-corrosion effect on the erosion of fly ash in a molten state, has strong corrosion resistance, significantly improved performance, greatly reduced probability of oxide precipitation, stable performance, and increased material service life.

[0071] The above embodiments are only used to illustrate the present invention, rather than to limit the present invention. Those skilled in the relevant technical field may make various changes or modifications without departing from the spirit and scope of the present invention. Therefore, all equivalent technical solutions should also belong to the scope of the present invention and should be defined by the claims.

Claims

1. A refractory material for a high-temperature melting furnace of waste incineration fly ash, characterized in that: The invention comprises the following components in percentage by mass: 30-36% zirconium oxide, 11-16% silicon dioxide, 1.15-1.5% sodium oxide and potassium oxide in total in percentage by mass, 2-3% yttrium oxide, 0.8-1.2% titanium oxide, and the balance is aluminum oxide.

2. The refractory material for a high-temperature melting furnace of waste incineration fly ash according to claim 1, characterized in that: The mass ratio of the sodium oxide to the potassium oxide is 7-9:1, and the mass ratio of the silicon dioxide to the sum of the sodium oxide and the potassium oxide is 9-10:

1.

3. The refractory material for high-temperature melting furnace of waste incineration fly ash according to claim 1, characterized in that: The total amount of impurities in the refractory material is less than 1%.

4. A refractory material for a high-temperature melting furnace of waste incineration fly ash according to any one of claims 1 to 3, characterized in that: The surface of the refractory material is also coated with an yttrium oxide coating with a coating thickness of 100-150 μm.

5. A method for preparing a refractory material for a high-temperature melting furnace of waste incineration fly ash as claimed in claim 1, characterized in that: The following steps are included: (1) Raw material preparation: weigh each component according to the above ratio and mix them evenly; (2) Mold group preparation: making sand mold group; (3) Raw material melting: The raw materials mixed in step (1) are melted in an electric arc furnace, and an oxygen blowing process is performed during the melting process. The temperature in the furnace is 2600-2700° C. and the constant temperature is controlled for 25-35 minutes; (4) Casting: After melting is completed, the temperature in the arc furnace is reduced to 1900-2100°C, and the molten liquid is cast into the mold assembly; (5) Insulation annealing: After casting, annealing and cooling are carried out in an insulation furnace. The cooling rate is: when the temperature is greater than 1200°C, the cooling rate is 15-25°C / h; when the temperature drops to 1200-800°C, the cooling rate is 10-15°C / h; when the temperature drops to 800-200°C, the cooling rate is 35-60°C / h; when the temperature drops below 200°C, it is naturally cooled to less than or equal to 50°C, and the refractory material made in the mold group is taken out.

6. The preparation method according to claim 5, characterized in that: Step (2) After the medium-sized group is manufactured, an yttrium oxide coating is applied to the casting surface with a coating thickness of 400-450 μm.

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