Refractory material for bottom of photovoltaic glass kiln and preparation method of refractory material

Abstract

The invention relates to the technical field of refractory materials, in particular to a refractory material for the bottom of a photovoltaic glass kiln and a preparation method of the refractory material. The zircon sand comprises the following preparation raw materials: 40%-45% of zircon concentrate, 2%-3% of sodium carbonate, 1%-2% of borax, 1%-2% of white mica, 1%-2% of titanium dioxide, 2%-3% of magnesium oxide, 1%-2% of aluminum nitride, 1%-2% of lead-rich sand and the balance of white corundum. The refractory material provided by the invention is particularly suitable for being used at the bottom of a photovoltaic glass kiln, is high in thermal shock resistance and resistant to erosion of molten glass, and can effectively solve the technical problem of poor thermal shock resistance of a refractory material for a glass kiln in production in the prior art.

Description

Technical Field

[0001] The present invention relates to the technical field of refractories, and particularly to a refractory for the bottom of a photovoltaic glass furnace and a preparation method thereof. Background Art

[0002] A glass furnace is an industrial furnace used for producing glass. Its main function is to melt glass raw materials into liquid glass at high temperatures. These raw materials usually include components such as quartz sand, soda ash, and limestone. The refractory materials at the bottom of the glass furnace need to withstand very high temperatures and long-term mechanical stresses. Therefore, the requirements for these materials are very high. For example, (1) High temperature resistance: It must be able to withstand the high temperatures generated during the glass melting process (usually above 1500°C) and maintain a stable structure at high temperatures for a long time without being easily softened or melted. (2) Erosion resistance: Currently, the problem encountered in the bottom of a photovoltaic glass furnace is that the refractory materials are usually subject to rather serious physical wear and chemical erosion, and there is also the action of thermal stress. This is because the molten glass and the raw materials of the glass have high corrosivity. In a continuously melting glass furnace, the refractory materials at the bottom need to resist the erosion of the glass liquid, the products of fuel combustion, and the chemical substances (such as alkali metals) from the raw materials. During this process, scratches or cracks will occur on the refractory materials at the bottom, and the cracks will continue to grow until the molten glass leaks out, thus affecting the service life of the refractory materials. (3) Thermal shock resistance: Refractory materials are prone to cracking or spalling when faced with sudden temperature changes. For example, during the start-up, shutdown, or abnormal operation of the furnace, the thermal shock suffered by the materials may cause damage. Therefore, it is required that they can withstand sharp temperature changes without cracking or spalling. (4) Abrasion resistance: Due to the flow of the glass liquid and the possible abrasion to the refractory materials during the cleaning and maintenance process, especially in some key areas of the furnace, such as the liquid flow hole and the cooling zone, the refractory materials need to have good abrasion resistance. (5) Creep resistance: Under high temperature conditions, the material should have sufficient strength and not deform or collapse due to the action of gravity. (6) Thermal expansion coefficient matching: Different types of refractory materials have different thermal expansion coefficients. The thermal expansion coefficients of the refractory materials used in different parts should be as matched as possible to avoid cracks or damage caused by thermal expansion and contraction. If the design is improper, stress may be generated between different materials during temperature changes, resulting in cracks or delamination. (7) Thermal conductivity: An appropriate thermal conductivity can help control the temperature distribution in the furnace, reduce heat loss, and improve energy efficiency.

[0003] In addition, the long-term high-temperature working environment will cause the aging of the refractory materials, manifested as changes in the microstructure, such as grain growth, grain boundary migration, etc., which will reduce the mechanical properties of the materials. In some cases, the glass liquid may also penetrate into the micropores of the refractory materials, affecting the integrity of the materials and possibly causing local overheating or other quality problems.

[0004] The temperature, degree of chemical erosion, speed during the operation of the furnace are closely related to the using parts and the types of molten glass. Of course, the quality of the refractory lining itself is also crucial. The refractory used for the bottom of the glass furnace will greatly affect the service life of the furnace and the production cost of the glass. The refractory currently used in photovoltaic glass furnaces has high strength and corrosion resistance, but has poor thermal shock resistance. When the temperature changes rapidly, some fine cracks may occur due to rapid cooling or heating.

[0005] Therefore, it is necessary to provide a refractory for glass furnaces with good anti-glass liquid erosion effect and strong thermal shock resistance. Summary of the Invention

[0006] The first aspect of the present invention provides a refractory for the bottom of a photovoltaic glass furnace. In terms of mass percentage, the raw materials for preparation include: 40%-45% of zircon concentrate, 2%-3% of sodium carbonate, 1%-2% of borax, 1-2% of muscovite, 1%-2% of titanium dioxide, 2%-3% of magnesium oxide, 1%-2% of aluminum nitride, 1%-2% of lead-rich sand, and white fused alumina to make up the balance to 100%.

[0007] In some embodiments, in terms of mass percentage, the content of zirconium dioxide in the zircon concentrate is 60-70%, and the content of silicon dioxide is 30-40%.

[0008] Zircon concentrate is a concentrated ore product obtained after beneficiation of zircon (with the chemical formula ZrSiO 4 ). Zircon is a zirconium-containing silicate mineral mainly composed of zircon, silicon and oxygen. It has a melting point as high as 2430°C, with high refractoriness and chemical stability, and has a wide range of applications in industry. In addition, zircon has good anti-glass liquid erosion performance. Its use as a refractory can significantly improve the service life and production efficiency of equipment, reduce the maintenance frequency, and thus reduce the production cost.

[0009] As an inorganic non-metallic material, zircon is relatively brittle and prone to fracture when subjected to mechanical shock or stress. There may be differences in the thermal expansion coefficients between zircon and other refractory components (such as alumina, silicate, etc.), which may cause stress inside the material during high-temperature use, leading to problems such as cracks or delamination. In addition, although zircon has good chemical stability, it may be eroded in certain specific chemical environments (such as strong acid or strong base conditions), thus affecting its durability.

[0010] The present invention does not limit the source of the zircon concentrate used, and it can be commercially available.

[0011] In some embodiments, the content of alumina in the white fused alumina is 80-90%.

[0012] White Fused Alumina is a high-quality artificial abrasive, mainly composed of aluminum oxide (Al 2 O 3 ). It is formed by melting high-purity alumina powder in an electric arc furnace at high temperature. White Fused Alumina has a hardness second only to diamond, with high hardness and good wear resistance. It can maintain stable performance in high-temperature environments, is suitable for high-temperature operations, has good chemical stability, and is not easily corroded by acids and alkalis.

[0013] However, there are also some inherent defects in the application of White Fused Alumina in refractory materials. Compared with some other refractory materials, White Fused Alumina has a relatively high coefficient of thermal expansion, which means that it is prone to generate large thermal stresses when the temperature changes. If the design is improper or there is no suitable compensation mechanism, it may lead to cracking or damage of the material. Although White Fused Alumina has good high-temperature resistance, its thermal conductivity is relatively low compared to some metals or metal oxides. This means that in some application scenarios that require efficient heat transfer, White Fused Alumina may not be the best choice. Although White Fused Alumina has a certain thermal shock resistance, under extreme temperature change conditions, especially during the process of rapidly cooling from high temperature to room temperature, there may still be cracks or delamination. In addition, when used in composites or in combination with other refractory materials, there may be compatibility problems between White Fused Alumina and the matrix material.

[0014] The present invention does not limit the source of the White Fused Alumina used, and it can be commercially available.

[0015] In some embodiments, the content of lead in the lead-rich sand is 10-15% by mass percentage.

[0016] Lead-rich sand refers to a mineral aggregate containing a relatively high concentration of lead (Pb), with lead as the main component, usually existing in the form of galena. Galena is the most common lead ore, and its chemical formula is PbS. Lead-rich sand usually has a relatively high density, with a specific gravity of approximately 4.5-7.5 g / cm 3 , and its color is mostly gray or black, with good luster and low hardness.

[0017] In some embodiments, the mass ratio of titanium dioxide, magnesium oxide, and aluminum nitride is (1-1.5):(2.5-3):(1-1.5).

[0018] In some embodiments, the apparent porosity of the refractory material is 1.2-2.0%, the normal temperature compressive strength is greater than 350 MPa, and the load softening temperature is greater than 1700 °C.

[0019] The second aspect of the present invention provides a method for preparing a refractory material for the bottom of a photovoltaic glass furnace, comprising the following steps:

[0020] S1. Mix the preparation raw materials and then feed them into an electric melting furnace, and melt them at a high temperature for 19 - 20 hours;

[0021] S2. Place the molten preparation raw materials obtained in S1 in a sand mold, cool them down to 800 - 1000 °C, and then send the sand mold into an annealing kiln;

[0022] S3. Let it stand in Zone 1 of the annealing kiln for 20 - 25 minutes; enter Zone 2 of the annealing kiln and let it stand for 20 - 25 minutes; enter Zone 3 of the annealing kiln and let it stand for 20 - 25 minutes; then reduce the temperature to 100 - 200 °C within 2 - 3 hours. After annealing, cool it naturally, demold, and then the refractory material is obtained.

[0023] In some embodiments, the high temperature in S1 is 1900 °C - 1950 °C.

[0024] In some embodiments, in S1, when the time for high - temperature melting is 16 - 17 hours, oxygen is introduced into the furnace to remove carbon.

[0025] In some embodiments, the temperature of Zone 1 of the annealing kiln is 650 - 750 °C, the temperature of Zone 2 of the annealing kiln is 550 - 650 °C, and the temperature of Zone 3 of the annealing kiln is 450 - 550 °C.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] 1. The refractory material proposed by the present invention is particularly suitable for use at the bottom of a photovoltaic glass kiln. This refractory material has strong thermal shock resistance and is resistant to glass liquid erosion, and can effectively solve the technical problem of poor thermal shock resistance of refractory materials used in glass kilns in current technology production.

[0028] 2. The preparation method of the refractory material of the present invention has a relatively simple production process, low cost, and no pollution. Specific Embodiments

[0029] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Apparently, the described embodiments are only a part of the embodiments of the present invention, rather than all of them. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0030] Example 1

[0031] This example provides a refractory material for the bottom of a photovoltaic glass kiln. In terms of mass percentage, the preparation raw materials include: zircon concentrate 42%, sodium carbonate 2.5%, borax 1.5%, muscovite 1.5%, titanium dioxide 1.5%, magnesium oxide 2.5%, aluminum nitride 1.5%, lead - rich sand 1.5%, and white fused alumina to make up the balance to 100%.

[0032] The content of zirconia in the zircon concentrate is 60 - 70%, and the content of silica is 30 - 40%.

[0033] The content of lead in the lead-rich sand is 10 - 15%.

[0034] The content of alumina in the white fused alumina is 80 - 90%.

[0035] This embodiment also provides a preparation method of a refractory for the bottom of a photovoltaic glass furnace, including the following steps:

[0036] S1. Mix the preparation raw materials and feed them into an electric melting furnace, melt at a high temperature of 1900°C for 20 h. When the high-temperature melting time reaches 17 h, introduce oxygen into the furnace to remove carbon.

[0037] S2. Place the molten preparation raw materials obtained in S1 in a sand mold, cool down to 900°C, and send the sand mold into an annealing kiln.

[0038] S3. Let it stand in Zone 1 of the annealing kiln at a temperature of 700°C for 25 minutes; enter Zone 2 of the annealing kiln at a temperature of 500°C and let it stand for 20 minutes; enter Zone 3 of the annealing kiln at a temperature of 500°C and let it stand for 25 minutes; then cool down to 150°C within 3 hours. After annealing, cool down naturally, demold, and obtain the refractory.

[0039] Example 2

[0040] This embodiment provides a refractory for the bottom of a photovoltaic glass furnace. In terms of mass percentage, the preparation raw materials include: 40% zircon concentrate, 2% sodium carbonate, 1% borax, 1% muscovite, 2% titanium dioxide, 23% magnesium oxide, 2% aluminum nitride, 2% lead-rich sand, and the white fused alumina makes up the balance to 100%.

[0041] The content of zirconia in the zircon concentrate is 60 - 70%, and the content of silica is 30 - 40%.

[0042] The content of lead in the lead-rich sand is 10 - 15%.

[0043] The content of alumina in the white fused alumina is 80 - 90%.

[0044] This embodiment also provides a preparation method of a refractory for the bottom of a photovoltaic glass furnace, including the following steps:

[0045] S1. Mix the preparation raw materials and feed them into an electric melting furnace, melt at a high temperature of 1900°C for 20 h. When the high-temperature melting time reaches 17 h, introduce oxygen into the furnace to remove carbon.

[0046] S2. Place the molten preparation raw materials obtained in S1 in a sand mold, cool down to 900 °C, and send the sand mold into an annealing kiln;

[0047] S3. Let it stand still in Zone 1 of the annealing kiln at a temperature of 700 °C for 25 minutes; enter Zone 2 of the annealing kiln at a temperature of 500 °C and let it stand still for 20 minutes; enter Zone 3 of the annealing kiln at a temperature of 500 °C and let it stand still for 25 minutes; then reduce the temperature to 150 °C within 3 hours. After annealing, cool it down naturally and demold to obtain the refractory material.

[0048] Example 3

[0049] This example provides a refractory material for the bottom of a photovoltaic glass kiln. By mass percentage, the preparation raw materials include: 45% zircon concentrate, 3% sodium carbonate, 2% borax, 2% muscovite, 2% titanium dioxide, 3% magnesium oxide, 2% aluminum nitride, 2% lead-rich sand, and white corundum to make up the balance to 100%.

[0050] The content of zirconium dioxide in the zircon concentrate is 60 - 70%, and the content of silicon dioxide is 30 - 40%.

[0051] The content of lead in the lead-rich sand is 10 - 15%.

[0052] The content of aluminum oxide in the white corundum is 80 - 90%.

[0053] This example also provides a preparation method for a refractory material for the bottom of a photovoltaic glass kiln, including the following steps:

[0054] S1. Mix the preparation raw materials and send them into an electric melting furnace, melt at a high temperature of 1900 °C for 20 h. When the high-temperature melting time is 17 h, introduce oxygen into the furnace to remove carbon;

[0055] S2. Place the molten preparation raw materials obtained in S1 in a sand mold, cool down to 900 °C, and send the sand mold into an annealing kiln;

[0056] S3. Let it stand still in Zone 1 of the annealing kiln at a temperature of 700 °C for 25 minutes; enter Zone 2 of the annealing kiln at a temperature of 500 °C and let it stand still for 20 minutes; enter Zone 3 of the annealing kiln at a temperature of 500 °C and let it stand still for 25 minutes; then reduce the temperature to 150 °C within 3 hours. After annealing, cool it down naturally and demold to obtain the refractory material.

[0057] Performance Test

[0058] Perform the following tests on the refractory material prepared in Example 1:

[0059] 1. Calculated by mass percentage, among which: ZrO 2 content 32% - 44%, Al 2 O3 Content: 36%-46%, SiO 2 Content: 13-16%, Na 2 O content: 1.2%-1.6%, Fe 2 O 3 +TiO 2 +CaO+MgO+Na 2 O+K 2 O+B 2 O 3 Content: 2.5-3%.

[0060] The test results are shown in Table 1.

[0061] Table 1

[0062] Density Apparent porosity Cold crushing strength Softening temperature under load Example 1 <![CDATA[3.75g / cm 3 > 1.8％ Greater than 350 MPa Greater than 1700 °C Example 2 <![CDATA[3.72g / cm 3 > 1.6％ Greater than 350 MPa Greater than 1700 °C Example 3 <![CDATA[3.69g / cm 3 > 1.65％ Greater than 350 MPa Greater than 1700 °C

[0063] The above is the preferred embodiment of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and modifications can be made, and these improvements and modifications should also be regarded as the protection scope of the present invention.

Claims

1. A refractory material for a photovoltaic glass furnace bottom, characterized in that: Calculated by mass percentage, the raw materials include: 40%-45% zircon concentrate, 2%-3% sodium carbonate, 1%-2% borax, 1-2% muscovite, 1%-2% titanium dioxide, 2%-3% magnesium oxide, 1%-2% aluminum nitride, 1%-2% lead-rich sand, and white corundum to make up the balance to 100%.

2. The refractory material for the bottom of a photovoltaic glass furnace according to claim 1, characterized in that: In terms of mass percentage, the zircon concentrate contains 60-70% zirconium dioxide and 30-40% silicon dioxide.

3. The refractory material for the bottom of a photovoltaic glass kiln according to claim 2, characterized in that: The content of aluminum oxide in the white corundum is 80-90%.

4. The refractory material for the bottom of a photovoltaic glass furnace according to claim 3, characterized in that: Measured in mass percentage, the lead content in the lead-rich sand is 10-15%.

5. The refractory material for the bottom of a photovoltaic glass kiln according to claim 4, characterized in that: The mass ratio of titanium dioxide, magnesium oxide and aluminum nitride is (1-1.5):(2.5-3):(1-1.5).

6. The refractory material for the bottom of a photovoltaic glass furnace according to claim 5, characterized in that: The refractory material has an apparent porosity of 1.2-2.0%, a compressive strength at room temperature greater than 350MPa, and a softening temperature under load greater than 1700°C.

7. A method for preparing a refractory material for a photovoltaic glass furnace bottom according to any one of claims 1 to 6, characterized in that: The steps include: S1. The prepared raw materials are mixed and sent into an electric furnace for high temperature melting for 19-20h; S2. The molten raw material prepared in S1 is placed in a sand mold, cooled to 800-1000°C, and the sand mold is sent to an annealing kiln; S3. Stand still in annealing furnace zone 1 for 20-25 minutes; enter annealing furnace zone 2, stand still for 20-25 minutes; enter annealing furnace zone 3, stand still for 20-25 minutes; then reduce the temperature to 100-200°C within 2-3 hours, cool naturally after annealing, demould, and obtain refractory material.

8. The preparation method according to claim 7, characterized in that: The high temperature in S1 is 1900°C-1950°C.

9. The preparation method according to claim 8, characterized in that: In S1, when the high temperature melting time is 16-17 hours, oxygen is introduced into the furnace for decarbonization.

10. The preparation method according to claim 9, characterized in that: The temperature of the annealing furnace zone 1 is 650-750°C, the temperature of the annealing furnace zone 2 is 550-650°C, and the temperature of the annealing furnace zone 3 is 450-550°C.