CN115636677A - Tin bath top cover brick for float glass production and preparation method thereof - Google Patents

Abstract

The invention provides a tin bath roof brick for the production of float glass and a preparation method thereof. The tin bath roof brick comprises the following raw material components in mass percentages: 60%-74% of andalusite aggregate, 60%-74% of andalusite fine Powder 10%‑15%, pure calcium aluminate cement 4%‑9%, alumina micropowder 3%‑9%, sol 3%‑8%, silica micropowder 0.1%‑5%, glass phase former 0.1%‑3 % and superplasticizer 0.1%‑0.5%. The preparation method comprises preparation of prefabricated material, preparation of mixed powder, preparation of mixed material, pouring molding, demoulding curing and high-temperature calcination to obtain the tin bath top cover brick. The invention can improve the thermal stability, corrosion resistance and thermal shock resistance of the prepared tin bath roof brick, and simultaneously reduce the thermal conductivity of the tin bath roof brick.

Description

Tin tank top cover brick for float glass production and preparation method thereof

technical field

The invention relates to the technical field of refractory materials, in particular to a tin bath roof brick for float glass production and a preparation method thereof.

Background technique

Glass is one of the important materials supporting the development of the national economy, and is widely used in construction, transportation, furniture and home appliances, instruments, aerospace and nuclear engineering and other fields. At present, the main process for producing glass is the float glass process. Tin bath is the key equipment for glass production in float glass process, and it plays a vital role in glass quality control.

The tin tank is mainly composed of the tank bottom and the top cover (the top cover is made of roof bricks). When the glass liquid at 1100-1200°C flows into the bottom surface of the tin tank from the furnace, the Na ₂ O, H ₂ S, etc. The corrosive gas is also brought into the tin bath, which will seriously erode the refractory material in the roof brick of the tin bath and produce drippings, which will have a great impact on the output and quality of the glass; and after the top cover is eroded, local Thinning will lead to uneven heat dissipation, lower thermal insulation performance and thermal efficiency, which not only makes it difficult to control the cooling temperature of the glass liquid, but also affects the adjustment of the thickness difference of the finished glass, reduces the quality of glass output, and increases the energy consumption of the glass melting furnace.

In addition, the thermal shock resistance of most tin bath top covers is poor at present, and cracks are easily generated, which increases the area and depth of gas erosion, resulting in shortened service life of the top cover and low economic efficiency. Therefore, the selection of tin bath roof structure and refractory material is very important, which directly affects the quality of glass production and the service life of tin bath.

In response to the above problems, the countermeasures currently adopted can be roughly divided into the following two categories:

One is to change the structure of the tin tank top cover. For example, the patent CN 202246389A proposes an arc-shaped combined roof brick structure, so that the vertical distance between the bottom of the tin bath and the roof brick gradually decreases from the edge to the middle, which solves the problem of uneven heat dissipation at the edge of the tin bath. Reduce the energy consumption of the tin bath, but it will still be corroded by some gases during use. Patent CN210764973U and patent CN 213388337U use refractory bricks and heat-insulating bricks to form a tin bath roof to enhance the corrosion resistance of the roof, but the superposition of multi-layer bricks will increase the weight of the roof, making construction difficult and less safe.

The other is to develop anti-erosion refractory materials as raw materials for tin bath roof bricks. For example, the mullite roof brick disclosed in the patent CN104326755A, the calcium aluminate roof brick disclosed in the patent CN 112194345A, and the sillimanite hot facing brick specially used for the tin bath roof brick disclosed in the patent CN112159080A, etc., such refractory Roof bricks have poor corrosion resistance at high temperatures, and thermal shock resistance is not ideal. Cracks are easily generated when the temperature changes greatly, and corrosive gases enter the gaps to increase the erosion contact surface, causing larger cracks. Even part of the glass phase and slag will drop on the tin bath, seriously affecting the quality of the glass.

To sum up, the main problems of tin bath roof bricks at present are poor thermal stability, weak corrosion resistance, easy cracking and dripping of glass phase and slag.

Contents of the invention

The purpose of the present invention is to provide a tin bath roof brick for float glass production and a preparation method thereof. By combining refractory raw materials in the raw material components, the thermal stability, corrosion resistance and anti-corrosion properties of the tin bath roof brick can be improved. Thermal shock resistance, while reducing the thermal conductivity of the tin bath roof brick. Its specific technical scheme is as follows:

In a first aspect, the application provides a tin bath roof brick for float glass production, which includes the following raw material components in mass percentages: 60%-74% of andalusite aggregate, 10%-74% of andalusite fine powder 15%, pure calcium aluminate cement 4%-9%, alumina micropowder 3%-9%, sol 3%-8%, silica micropowder 0.1%-5%, glass phase forming agent 0.1%-3% and water reducing agent Agent 0.1%-0.5%.

Further, the andalusite aggregate and the andalusite fine powder both include the following components in mass percentage: the mass percentage of Al ₂ O ₃ ≥ 58%, the mass percentage of Fe ₂ O ₃ ≤ 0.5% and the sum of the mass percentages of Na ₂ O, MgO and K ₂ O is ≤0.5%.

Further, the sol is at least one of silica sol, aluminum sol and silica-alumina sol.

Further, the glass phase forming agent includes at least one of spodumene, albite, and potassium-containing sodium mineral mixtures (including sodium carbonate, potassium carbonate and other mineral mixtures).

Further, in the pure calcium aluminate cement, the following components are included in mass percentage: the mass percentage of _Al2O3 is 70%-80% and the mass percentage of CaO is ₂₀ %-30% ;

The alumina fine powder is α-Al ₂ O ₃ ; wherein, in terms of mass percentage, the purity of α-Al ₂ O ₃ is greater than 99%;

In the microsilica powder, the mass percentage of _SiO2 is ≥95%;

The water reducer includes at least one of sodium tripolyphosphate, sodium polyacrylate and sodium hexametaphosphate.

Further, the particle size of the andalusite aggregate is ≤5mm; the particle size of the andalusite fine powder is 200-325 mesh; the particle size of the pure calcium aluminate cement is not more than 300 mesh; the particle size of the alumina micropowder is 2-5μm; the particle size of silica powder is 0.3-2μm.

In a second aspect, the application provides a method for preparing the tin bath roof brick for the production of float glass, which comprises the following steps:

Step S1, preparing prefabricated material

Weigh the required mass percentage of andalusite fine powder and sol, stir and mix evenly, heat to about 1200-1600°C, keep warm for 1-4h, stop heating, cool down to room temperature, take it out and place it in a ball mill for grinding. Until the particle size is 5-25 microns, so as to prepare the prefabricated material;

Step S2, preparing mixed powder

Weigh the required mass percentage of pure calcium aluminate cement, alumina micropowder, silica micropowder, water reducing agent and glass phase forming agent, pour it into a ball mill, mix and grind, and mix it with the prefabricated material in step S1 after grinding Obtain mixed powder evenly;

Step S3, preparation of mixture

Weigh the required mass percentage of andalusite aggregate and add it to the mixed powder in step S2, add water, stir evenly, and obtain the mixed material;

Step S4, pouring molding

Pour the mixture in step S3 into a mold to form a green body, and vibrate the mold to avoid air bubbles inside the green body;

Step S5, demoulding maintenance

Put the mold with the green body in step S4 at room temperature or at a constant temperature for 12-24 hours, take out the mold after the green body is formed, and maintain it naturally for 12-24 hours;

Step S6, high temperature calcination

Put the green body after demoulding and curing in step S5 into a high-temperature kiln for calcination, and obtain a tin bath roof brick after calcination.

Further, in step S5, the conditions for the calcination are as follows: the body is heated to 150°C within 48 hours at a heating rate of 2.2-3.2°C/h; after being kept at 150°C for 24 hours, the The green body is heated to 600°C within 48-72h, and the heating rate is 17.5-19.5°C/h; after being kept at 600°C for 24h, the green body is heated to 1400°C within 24-36h, and the heating rate is 25 -35°C/h; after constant temperature at 1400°C for 12h, the green body is gradually cooled down to 100°C within 24-48h to complete calcination and exit the kiln, wherein the cooling rate is 45-55°C/h.

Further, in step S5, the temperature of the natural curing is 10-35°C.

Further, in step S3, the mass of added water accounts for 5%-10% of the total mass of raw material components;

In step S4, the way of vibrating the mold includes manual vibration or mechanical vibration, the vibration time is ≤25 minutes, and the vibration frequency is 125-250 times/minute.

Applying the technical solution of the present invention has the following beneficial effects:

(1) The tin bath top cover brick used for the production of float glass described in the present invention uses each raw material component in combination, and in conjunction with the corresponding mass proportion, makes the prepared top cover brick have thermal conductivity less, It has the advantages of high strength, light weight, good thermal shock resistance and corrosion resistance, which in turn facilitates the improvement of the production quality of glass.

(2) The preparation method of the tin bath roof brick used in the production of float glass described in the present invention, the present invention is a low-scale high-temperature composite phase formed by combining andalusite fine powder and sol in the raw material components and calcining pretreatment together Powder, in which there are mineral phases such as mullite, quartz and undecomposed andalusite, they still have the same ability to expand, decompose and react with other mineral phases during use. Controlled, can prevent the generation of new cracks and crack expansion, thereby improving the thermal shock resistance of the finished product, reducing cracking and glass phase dripping;

By using sol in the raw material components, the gaps generated by the cracks of the roof bricks are effectively filled during the calcination process, and the compactness of the roof bricks is increased, which not only prevents the erosive gas from entering the roof bricks, but also curbs the impact of the erosive gases on the roof bricks. Deep corrosion, while improving the strength of the roof brick, prolonging the service life; moreover, it can also reduce the thermal conductivity of the tin bath roof brick;

By using a glass phase forming agent in the raw material components, the roof brick can react with the silica powder raw material or the product silica formed by the decomposition of andalusite aggregate at about 1000°C to form a glass phase with high viscosity, which can not only seal The pores on the inner surface of the roof brick prevent gas from escaping, and the formed glass phase has a high viscosity and is not easy to drip. The surface of the material is relatively dense. When the density of the material surface increases, its anti-seepage and anti-slag performance will also be improved accordingly, so that the roof brick has good thermal insulation and gas anti-seepage performance;

The invention greatly improves the thermal stability, corrosion resistance and thermal shock resistance of the tin bath top cover brick by utilizing the synergistic effect among various raw material components, and can reduce the thermal conductivity of the tin bath top cover brick at the same time. In addition, the roof bricks prepared by the present invention can also be stacked and used directly, thereby greatly reducing the weight of the tin tank roof and facilitating construction.

(3) The preparation method of the tin bath top cover brick used in the production of float glass described in the present invention, through step S1, carry out a preliminary treatment to andalusite fine powder and sol, obtain comparatively dense and mineral phase composition complex prefabricated material ; Through step S2, various fine powder raw materials are mixed to make them evenly contact with each other, so as to ensure that the quality of the finally obtained roof brick is stable; through step S3, the mixture is obtained; through step S4, the green body of the roof brick is obtained; through Step S5, natural maintenance allows the raw materials to interact and form together; through step S6, the mineral composition of the raw materials can be selectively changed and crystal transformation occurs, which can improve the strength of the roof brick; through the combined use of steps S1-S6, it can be obtained Roof brick with low thermal conductivity and strong thermal shock resistance. The preparation method has the advantages of simple process, low cost and easy realization of industrialized production, and the prepared roof brick has excellent performance and is suitable for popularization, application and production.

Detailed ways

The technical solutions in the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Apparently, the described embodiments are only some of the embodiments of the present invention, not all of them. All other embodiments obtained by persons of ordinary skill in the art based on the embodiments of the present invention belong to the protection scope of the present invention.

Example 1:

A tin bath top cover brick for float glass production, comprising the following raw material components in mass percentage: 70% andalusite aggregate, 12% andalusite fine powder, 6% pure calcium aluminate cement, and 5% alumina micropowder , sol 4%, silica powder 1.8%, glass phase forming agent 0.9% and water reducing agent 0.3%.

Both the andalusite aggregate and the andalusite fine powder include the following components in mass percentage: Al ₂ O ₃ mass percentage 60%-65%, Fe ₂ O ₃ mass percentage 0.1% -0.3% and the sum of the mass percentages of Na ₂ O, MgO and K ₂ O ≤ 0.5%, wherein the mass percentage of Na ₂ O is 0.05%, the mass percentage of MgO is 0.05%, K ₂ The mass percent content of O is 0.05%.

The sol is silica sol.

The glass phase forming agent is albite.

In the pure calcium aluminate cement, the following components in mass percentage are included: the mass percentage of _Al2O3 is 75% and the mass percentage of CaO is ₂₅ %;

The alumina fine powder is α-Al ₂ O ₃ ; wherein, in terms of mass percentage, the purity of α-Al ₂ O ₃ is 99.9%;

In the microsilica powder, SiO _The mass percent composition is 95%;

The water reducer is sodium tripolyphosphate.

The particle size of the andalusite aggregate is ≤5 mm; the particle size of the andalusite fine powder is 200-325 mesh; the particle size of the pure calcium aluminate cement is not more than 300 mesh; the particle size of the alumina micropowder is 2-4 μm ; The particle size of silica powder is 0.3-2μm.

A preparation method for preparing the tin bath roof brick for the production of said float glass, comprising the following steps:

Step S1, preparing prefabricated material

Weigh the andalusite fine powder and sol in the required mass percentage, stir and mix them evenly, heat them in a muffle furnace to 1400°C, keep them warm for 2 hours, stop heating, cool down to room temperature, take them out and place them in a ball mill for grinding , until the particle size is 10-20 microns, thereby making a prefabricated material;

Step S2, preparing mixed powder

Weigh the required mass percentages of pure calcium aluminate cement, alumina micropowder, silica micropowder, water reducing agent and glass phase forming agent, pour them into a ball mill in turn, mix and grind, and grind until the particle size of each raw material is the same and mix evenly Mix it with the preform in step S1 and stir evenly to obtain a mixed powder;

Step S3, preparation of mixture

Weigh the required mass percentage of the andalusite aggregate and add it to the mixed powder in step S2, add water, and stir evenly to obtain the mixed material.

Step S4, pouring molding

Pour the mixture obtained in step S3 into a mold to form a green body, and vibrate the mold to avoid air bubbles inside the green body;

Step S5, demoulding maintenance

The mold with the green body in step S4 is left to stand at room temperature for 18 hours, and after the green body is formed, the mold is taken out and naturally cured for 15 hours;

Step S6, high temperature calcination

Put the green body after demoulding and curing in step S5 into a high-temperature kiln for calcination, and obtain a tin bath roof brick after calcination.

In step S6, the calcination conditions are as follows: the green body is heated to 150°C within 48 hours, and the heating rate is 2.5-3.0°C/h; after being kept at 150°C for 24 hours, the green body is Raise the temperature to 600°C within 48-72 hours, with a heating rate of 18-19°C/h; after keeping the temperature at 600°C for 24 hours, raise the temperature of the green body to 1400°C within 24-36 hours, with a heating rate of 28-30°C /h; after constant temperature at 1400°C for 12h, the green body is gradually cooled down to 100°C within 24-48h to complete the calcination and exit the kiln, wherein the cooling rate is 48-50°C/h.

In step S5, the temperature of the natural curing is 20°C.

In step S3, the mass of added water accounts for 8% of the total mass of raw material components;

In step S4, the way of vibrating the mold includes artificial vibration or mechanical vibration, the vibration time is 20 minutes, and the vibration frequency is 125 times per minute.

The present invention has also made Examples 2-5 and Comparative Examples 1-6. Unlike Example 1, Examples 2-5 only differ in the amount of each raw material component, and the specific amounts are as shown in Table 1 , while table 1 also shows common commercially available tin bath roof bricks (the common commercially available tin bath roof bricks are the tin bath roof bricks in the tin bath brick series of Xinxiang Qiangxin Refractories Co., Ltd.) and the The performance data of the tin bath roof tiles made by Examples 1-5 and Comparative Examples 1-6. The data in Table 1 were obtained by using the GB/T 30873-2014 test method for thermal shock resistance of refractory materials.

Table 1

Continued Table 1

As can be seen from the data in Table 1, the bulk density of the thermal shock-resistant float glass tin bath roof bricks obtained in Examples 1-5 is less than that of common commercially available tin bath roof bricks, and the porosity is greater than that of common commercially available tin bath roof bricks. The cover brick is not easy to crack and slag; the thermal conductivity is lower than that of ordinary commercially available tin bath top cover bricks, and it has good thermal shock resistance. Experimental results show that the float glass tin bath roof brick prepared by the invention has higher temperature resistance and better thermal shock resistance than the common commercially available tin bath roof bricks.

Compared with Examples 1-5, the use of too high or too low amount of andalusite fine powder in Comparative Example 1-2 will lead to a decline in the thermal shock resistance of the prepared tin bath roof brick.

Compared with Examples 1-5, comparative examples 3-4 do not use glass phase forming agent or adopt excessively high consumption of glass phase forming agent, which will cause the thermal shock resistance of the prepared tin bath roof brick to decline, while Increased thermal conductivity results in increased thermal conductivity properties.

Compared with Examples 1-5, Comparative Examples 5-6 do not use sol or use too high a dosage of sol, which will cause the thermal shock resistance and refractoriness of the prepared tin bath roof brick to decrease, while the thermal conductivity increases The thermal conductivity performance is increased.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and changes. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims (10)

1. A tin bath top cover brick for producing float glass is characterized by comprising the following raw material components in percentage by mass: 60 to 74 percent of andalusite aggregate, 10 to 15 percent of andalusite fine powder, 4 to 9 percent of pure calcium aluminate cement, 3 to 9 percent of alumina micro powder, 3 to 8 percent of sol, 0.1 to 5 percent of silica micro powder, 0.1 to 3 percent of glass phase forming agent and 0.1 to 0.5 percent of water reducing agent.

2. The tin bath roof brick for producing float glass according to claim 1, wherein the andalusite aggregate and the andalusite fine powder both comprise the following components in percentage by mass: al (Al) ₂ O ₃ The mass percentage of the Fe content is more than or equal to 58 percent, and the Fe content ₂ O ₃ The mass percentage content of the sodium-doped zinc oxide is less than or equal to 0.5 percent and Na ₂ O, mgO and K ₂ The sum of the mass percentage of O is less than or equal to 0.5 percent.

3. The tin bath roof tile for float glass production according to claim 1, wherein the sol is at least one of silica sol, aluminum sol and silica-alumina sol.

4. A tin bath roof tile for use in the production of float glass as claimed in claim 1 wherein the glass phase former comprises at least one of spodumene, albite and a mixture of potassium and sodium containing minerals.

5. The tin bath roof brick for producing float glass according to claim 1, characterized in that the pure calcium aluminate cement comprises the following components in percentage by mass: al (aluminum) ₂ O ₃ 70-80 percent of CaO and 20-30 percent of CaO;

the alumina micro powder is alpha-Al ₂ O ₃ (ii) a Wherein, calculated by mass percent, alpha-Al ₂ O ₃ Has a purity of greater than 99%;

in the fine silicon powder, siO ₂ The mass percentage content of the compound is more than or equal to 95 percent;

the water reducing agent comprises at least one of sodium tripolyphosphate, sodium polyacrylate and sodium hexametaphosphate.

6. The tin bath roof tile for float glass production as claimed in claim 1, wherein the particle size of the andalusite aggregate is no greater than 5mm; the particle size of the andalusite fine powder is 200-325 meshes; the granularity of the pure calcium aluminate cement is not more than 300 meshes; the grain diameter of the alumina micro powder is 2-5 μm; the particle size of the silicon micropowder is 0.3-2 μm.

7. A method of manufacturing a tin bath roof tile for float glass production according to any one of claims 1 to 6, comprising the steps of:

step S1, preparing a prefabricated material

Weighing andalusite fine powder and sol in required mass percentage, stirring and uniformly mixing, heating to about 1200-1600 ℃, preserving heat for 1-4h, stopping heating, cooling to room temperature, taking out, and then placing in a ball mill for grinding until the particle size is 5-25 microns, thereby preparing a prefabricated material;

step S2, preparing mixed powder

Weighing pure calcium aluminate cement, alumina micropowder, silica micropowder, a water reducing agent and a glass phase forming agent in required mass percentage, pouring the materials into a ball mill for mixing and grinding, and mixing and stirring the materials with the prefabricated material in the step S1 uniformly after grinding to obtain mixed powder;

step S3, preparing a mixture

Weighing andalusite aggregate with the required mass percentage, adding the andalusite aggregate into the mixed powder in the step S2, adding water, and uniformly stirring to obtain a mixture;

step S4, casting and molding

Pouring the mixture into a mold to form a blank body, and vibrating the mold to avoid bubbles from being generated in the blank body;

step S5, demolding and maintaining

Standing the mould filled with the blank in the step S4 at normal temperature or constant temperature for 12-24h, taking out the mould after the blank is formed, and naturally curing for 12-24h;

step S6, high-temperature calcination

And (5) placing the blank subjected to demolding and curing in the step (S5) into a high-temperature kiln for calcining, and obtaining the tin bath top cover brick after calcining.

8. The method according to claim 7, wherein in step S6, the calcination is performed under the following conditions: heating the blank to 150 ℃ within 48h, wherein the heating rate is 2.2-3.2 ℃/h; keeping the temperature at 150 ℃ for 24h, and then heating the blank to 600 ℃ within 48-72h at the heating rate of 17.5-19.5 ℃/h; keeping the temperature at 600 ℃ for 24h, heating the blank to 1400 ℃ within 24-36h, wherein the heating rate is 25-35 ℃/h; keeping the temperature at 1400 ℃ for 12h, gradually cooling the green body to 100 ℃ within 24-48h, completing calcination, and discharging from the kiln, wherein the cooling rate is 45-55 ℃/h.

9. The method according to claim 7, wherein the temperature for natural curing is 10 to 35 ℃ in step S5.

10. The preparation method according to claim 7, wherein in step S3, the mass of the added water accounts for 5-10% of the total mass of the raw material components;

in step S4, the mode of vibrating the mold comprises manual vibration or mechanical vibration, the vibration time is less than or equal to 25 minutes, and the vibration frequency is 125-250 times/minute.