Forsterite checker brick for heat storage chamber of hot blast stove

Abstract

The invention relates to a forsterite checker brick for a heat storage chamber of a hot blast stove, which is characterized by comprising the following components in percentage by weight: 70-75wt% of natural forsterite; 10 to 20 weight percent of clay; 5-10 wt% of magnesium oxide; 1-3 wt% of magnesium chloride; and 4-8 wt% of a binding agent. The invention has the following beneficial effects: natural forsterite is used as a main material, a certain amount of clay is added as an aggregate, a proper amount of magnesium chloride and magnesium oxide are introduced as a modifier, the brick is weakly alkaline, the main mineral phase is M2S and MgAl2O4, the apparent porosity is small and is about 13-15%, the load deformation temperature is high and is about 1720-1800 DEG C, and the brick has good thermal insulation performance. And the product has excellent chemical mineral structure, physical property and thermal shock resistance.

Description

Technical Field

[0001] The invention relates to the technical field of refractory materials, in particular to a forsterite checker brick used for building a high-temperature zone of a heat storage chamber of a hot blast furnace. Background Art

[0002] Checker brick is a heat-carrying and heat-storing body, which should have many excellent thermal characteristics such as strong heat exchange capacity, large heat storage area, smooth ventilation, and low resistance. As a heat transfer medium, checker brick is mainly used in the heat storage chamber of the blast furnace hot blast stove. It plays a role of heat storage during the "burning period" and heats the cold air into hot air through convection heat exchange and radiation heat exchange during the "air supply period". At present, according to the technical requirements of different temperature zones in the heat storage chamber, checker bricks made of materials such as silica and clay are generally selected. In some hot blast stoves, checker bricks made of high alumina, mullite, sillimanite and other materials are also selected.

[0003] The most important requirement for the checker bricks in the high temperature area of ​​the regenerator is to have good high temperature volume stability, corrosion resistance and creep resistance. Silica bricks have these characteristics and are cheap, so they are widely used in high-temperature hot blast furnaces at home and abroad. However, with the development of large-scale blast furnaces and coke ovens (carbonization chambers are increased from 4 meters to 7 meters), the requirements for the quality and size of the refractory materials used have also been further improved. The existing silica brick production process needs to be strengthened in terms of increasing the SiO2 content in silica bricks, reducing impurities, especially reducing the Al2O3 content, and improving product density, compressive strength, and reducing porosity. In addition, silica bricks are a variety of acidic refractory materials, which have a strong ability to resist corrosion by acidic slag or acidic melt, but have poor resistance to corrosion by alkaline substances. Generally, they must not contact alkaline slag, and they have large expansion coefficients, poor thermal shock resistance (usually 1 to 4 water cooling cycles), and low refractoriness (generally 1690 to 1730℃), which also leads to a very limited scope of application. Summary of the invention

[0004] In order to overcome the existing technical defects, the technical problem solved by the present invention is to provide a forsterite lattice brick for the regenerator of a coke oven hot blast stove, which is a weakly alkaline lattice brick with natural forsterite as the main material, a certain amount of clay added as aggregate, and an appropriate amount of magnesium chloride and magnesium oxide introduced as modifiers. The main mineral phases are M2S and MgAl2O4, the apparent porosity is small, about 13-15%, the load deformation temperature is high, about 1720-1800°C, and the brick has excellent chemical mineral structure, physical properties and thermal shock stability.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] A forsterite checker brick for a hot blast furnace regenerator, characterized in that it comprises the following components by weight percentage:

[0007] Natural forsterite 70-75wt%;

[0008] Clay 10~20wt%;

[0009] Magnesium oxide 5-10wt%;

[0010] Magnesium chloride 1-3wt%;

[0011] Binder 4~8wt%.

[0012] Furthermore, the binder is a mixture of 20% MgO·SiO2 solution and molasses, wherein the weight percentage of 20% MgO·SiO2 solution to molasses is 0.8-1.5:1.

[0013] Furthermore, a method for preparing forsterite checker bricks for hot blast furnace regenerators is characterized by comprising the following steps:

[0014] 1) According to the composition of the checker bricks, 70-80wt% of natural forsterite, 10-15wt% of clay, 0-6wt% of magnesium chloride, 5-10wt% of magnesium oxide, and 4-8wt% of a binder are weighed in mass percentage to prepare ingredients;

[0015] 2) Grinding natural forsterite and clay together for 20 minutes and mixing them evenly to obtain co-ground powder;

[0016] 3) Add magnesium oxide and magnesium chloride to the co-ground powder, add a binder, and co-grind and stir for 15 minutes;

[0017] 4) Using a semi-dry machine to press into a checkered brick shape;

[0018] 5) Under room temperature conditions, place the checkered brick mold naturally for 20 to 30 hours and then put it into the kiln for calcination. First, slowly raise the temperature to 200 to 300°C and keep the temperature constant for 1.8 to 2.5 hours; after the natural water in the brick is drained, increase the calcination rate by 4 to 6°C / hour, continue to raise the temperature to 700 to 850°C, and keep the temperature constant for 2 to 3 hours; after the free water and low-melting substances in each mineral are burned out, quickly raise the temperature to 1550 to 1650°C and keep the temperature constant for 4.5 to 5.5 hours; open the kiln when it cools naturally to 650 to 750°C, and finally cool naturally to room temperature.

[0019] Furthermore, after mixing in step 3), the particle size of the mixture is less than 1 mm, of which: 0.8-1 mm accounts for 15%, 0.5-0.8 mm accounts for 20%, 0.1-0.5 mm accounts for 30%, and less than 0.1 mm accounts for 35%.

[0020] Furthermore, a forsterite checker brick for a hot blast furnace regenerator is characterized in that it comprises the following components by weight percentage:

[0021] Natural forsterite 73wt%;

[0022] Clay 12.5wt%;

[0023] Magnesium oxide 7.5wt%;

[0024] Magnesium chloride 2wt%;

[0025] Binder 5wt%.

[0026] Furthermore, the binder is a mixture of 20% MgO·SiO2 solution and molasses, wherein the weight percentage of the 20% MgO·SiO2 solution to the molasses is 1.2:1.

[0027] Furthermore, a method for preparing forsterite checker bricks for a hot blast furnace regenerator comprises the following steps:

[0028] 1) According to the composition of the checker bricks, 73 kg of natural forsterite, 12.5 kg of clay, 7.5 kg of magnesium oxide, 2 kg of magnesium chloride, and 5 kg of binder were weighed according to mass percentage to prepare the ingredients;

[0029] 2) putting natural forsterite and clay into a mixer, rolling and mixing them for 20 minutes, and mixing them evenly to obtain co-ground powder;

[0030] 3) Add magnesium oxide (MgO) and magnesium chloride (MgCl2) to the co-ground powder, add a binder to moisten it, continue rolling and co-grinding for 15 minutes, and obtain a mixture with a particle size of less than 1 mm, of which: 0.8-1 mm accounts for 15%, 0.5-0.8 mm accounts for 20%, 0.1-0.5 mm accounts for 30%, and less than 0.1 mm accounts for 35%;

[0031] 4) Use 630 hollow brick press to press into lattice brick shape;

[0032] 5) Under room temperature conditions, place the checkered brick mold naturally for 24 hours and then calcine it in a tunnel kiln. First, slowly heat it to 250℃ and keep it constant for 2.2 hours. After the natural water in the brick is drained, increase the calcination rate by 5℃ / hour, continue to heat it to 750℃, and keep it constant for 2.5 hours. After the free water and low-melting substances in each mineral are burned out, quickly heat it to 1600℃ and keep it constant for 5 hours. Open the kiln when it cools naturally to 700℃, and finally cool it naturally to room temperature.

[0033] Compared with the prior art, the present invention has the following beneficial effects:

[0034] 1) The forsterite checker brick of the present invention is mainly composed of natural forsterite (containing magnesium oxide and silicon dioxide as main components, with a theoretical chemical formula of 2MgO·SiO2 or Mg2SiO4, a high temperature melting point of 1910°C, and a theoretical chemical composition of MgO content of 57.2% and SiO2 content of 42.8%), with a mass fraction of MgO of 35% to 55%, a ratio of MgO to SiO2 of 0.94 to 1.33, and has a weak alkalinity close to neutrality, so it has strong resistance to alkaline slag, high refractoriness, and a high load deformation temperature of about 1720 to 1800°C;

[0035] 2) The forsterite checker brick of the present invention has an appropriate amount of magnesium oxide (MgO) added, which can effectively prevent the generation of low-melting-point metasilicate (such as MgO·SiO2) and magnetite (Te3O4) when natural forsterite is calcined; the addition of an appropriate amount of magnesium chloride can effectively improve the compactness of the brick structure, reduce the porosity, and optimize the various performance indicators of the brick until they reach the best; the increase in calcination temperature is conducive to the generation of magnesium aluminum spinel MgAl2O4 and forsterite M2S, and the introduction of magnesium chloride (MgCl2) also increases the generation of M2S. The presence of MgAl2O4 and M2S greatly improves the strength and acid resistance of the checker brick;

[0036] 3) The forsterite lattice brick of the present invention is a weakly alkaline lattice brick with natural forsterite as the main material, a certain amount of clay as aggregate, and an appropriate amount of magnesium chloride and magnesium oxide as modifiers. The main mineral phases are M2S and MgAl2O4, the apparent porosity is small, about 13-15%, the load deformation temperature is high, about 1720-1800°C, and it has excellent chemical mineral structure, physical properties and thermal shock stability. DETAILED DESCRIPTION

[0037] The technical solution of the present invention will be further 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.

[0038] [Example 1]:

[0039] A forsterite checker brick for a hot blast furnace regenerator comprises the following components by weight percentage:

[0040] Natural forsterite 73wt%;

[0041] Clay 12.5wt%;

[0042] Magnesium oxide 7.5wt%;

[0043] Magnesium chloride 2wt%;

[0044] Binder 5wt%.

[0045] Furthermore, the binder is a mixture of 20% MgO·SiO2 solution and molasses, wherein the weight percentage of the 20% MgO·SiO2 solution to the molasses is 1.2:1.

[0046] Furthermore, a method for preparing forsterite checker bricks for a hot blast furnace regenerator comprises the following steps:

[0047] 1) According to the composition of the checker bricks, 73 kg of natural forsterite, 12.5 kg of clay, 7.5 kg of magnesium oxide, 2 kg of magnesium chloride, and 5 kg of binder were weighed according to mass percentage to prepare the ingredients;

[0048] 2) putting natural forsterite and clay into a mixer, rolling and mixing them for 20 minutes, and mixing them evenly to obtain co-ground powder;

[0049] 3) Add magnesium oxide (MgO) and magnesium chloride (MgCl2) to the co-ground powder, add a binder to moisten it, continue rolling and co-grinding for 15 minutes, and obtain a mixture with a particle size of less than 1 mm, including: 0.8-1 mm 15%, 0.5-0.8 m 20%, 0.1-0.5 mm 30%, less than 0.1 mm 35%;

[0050] 4) Use 630T hollow brick press to press into checkered brick shape;

[0051] 5) Under room temperature conditions, place the checkered brick mold naturally for 24 hours and then calcine it in a tunnel kiln. First, slowly heat it to 250℃ and keep it constant for 2.2 hours. After the natural water in the brick is drained, increase the calcination rate by 5℃ / hour, continue to heat it to 750℃, and keep it constant for 2.5 hours. After the free water and low-melting substances in each mineral are burned out, quickly heat it to 1600℃ and keep it constant for 5 hours. Open the kiln when it cools naturally to 700℃, and finally cool it naturally to room temperature.

[0052] In this embodiment, natural forsterite is selected from Yingkou area of ​​Liaoning Province, and the average mass fraction of the chemical composition of the original ore is: SiO2: 34.43%; CaO: 0.32%; MgO: 41.10%; Fe2O3: 4.28%; FeO: 2.52%; Al2O3: 2.71%; LOS: 11.72%; MgO / SiO2: 1.19.

[0053] In this embodiment, 7.5wt% of magnesium oxide (MgO) is introduced, the purpose of which is to combine it with SiO2 in the raw material to form Mg2SiO4 and combine it with R2O2 to form a spinel-type mineral, which can effectively prevent the formation of low-melting-point metasilicates (such as MgO·SiO2) and magnetite (Te3O4) when natural forsterite is calcined.

[0054] In this embodiment, 2 wt% of magnesium chloride (MgCl2) is added to effectively improve the compactness of the brick structure, and the volume density reaches 3.52 g / cm 3 , reducing the apparent porosity to about 13.1, so that the various performance indicators of the brick are optimized to the best.

[0055] In this embodiment, molasses is selected as the binder, and molasses is a multifunctional binder, which has the functions of binding, lubrication, anti-hydration and sintering promotion, and is helpful to improve the performance and quality of refractory materials.

[0056] [Example 2]:

[0057] A forsterite checker brick for a hot blast furnace regenerator comprises the following components by weight percentage:

[0058] Natural forsterite 70wt%;

[0059] Clay 13.5wt%;

[0060] Magnesium oxide 8.5wt%;

[0061] Magnesium chloride 2.5wt%;

[0062] Binder 5.5wt%.

[0063] Furthermore, the binder is a mixture of 20% MgO·SiO2 solution and molasses, wherein the weight percentage of the 20% MgO·SiO2 solution to the molasses is 1.5:1.

[0064] Furthermore, a method for preparing forsterite checker bricks for a hot blast furnace regenerator comprises the following steps:

[0065] 1) According to the composition of the checker bricks, 70 kg of natural forsterite, 13.5 kg of clay, 8.5 kg of magnesium oxide, 2.5 kg of magnesium chloride, and 5.5 kg of binder were weighed according to mass percentage to prepare the ingredients;

[0066] 2) putting natural forsterite and clay into a mixer, rolling and mixing them for 20 minutes, and mixing them evenly to obtain co-ground powder;

[0067] 3) Add magnesium oxide (MgO) and magnesium chloride (MgCl2) to the co-ground powder, add a binder to moisten it, continue rolling and co-grinding for 15 minutes, and obtain a mixture with a particle size of less than 1 mm, including: 0.8-1 mm 15%, 0.5-0.8 m 20%, 0.1-0.5 mm 30%, less than 0.1 mm 35%;

[0068] 4) Use 630T hollow brick press to press into checkered brick shape;

[0069] 5) Under room temperature conditions, place the checkered brick mold naturally for 24 hours and then calcine it in a tunnel kiln. First, slowly raise the temperature to 280℃ and keep it constant for 2.5 hours. After the natural water in the brick is drained, increase the calcination rate by 5℃ / hour, continue to raise the temperature to 730℃, and keep it constant for 2.5 hours. After the free water and low-melting substances in each mineral are burned out, quickly raise the temperature to 1550℃ and keep it constant for 5 hours. Open the kiln when it cools naturally to 720℃, and finally cool naturally to room temperature.

[0070] [Example 3]

[0071] A forsterite checker brick for a hot blast furnace regenerator comprises the following components by weight percentage:

[0072] Natural forsterite 75wt%;

[0073] Clay 11wt%;

[0074] Magnesium oxide 7.5wt%;

[0075] Magnesium chloride 1.5wt%;

[0076] Binder 5wt%.

[0077] Furthermore, the binder is a mixture of 20% MgO·SiO2 solution and molasses, wherein the weight percentage of 20% MgO·SiO2 solution to molasses is 0.8:1.

[0078] Furthermore, a method for preparing forsterite checker bricks for a hot blast furnace regenerator comprises the following steps:

[0079] 1) According to the composition of the checker bricks, 78 kg of natural forsterite, 10 kg of clay, 6.5 kg of magnesium oxide, 1.5 kg of magnesium chloride, and 4 kg of binder were weighed according to mass percentage to prepare the ingredients;

[0080] 2) putting natural forsterite and clay into a mixer, rolling and mixing them for 20 minutes, and mixing them evenly to obtain co-ground powder;

[0081] 3) Add magnesium oxide (MgO) and magnesium chloride (MgCl2) to the co-ground powder, add a binder to moisten it, continue rolling and co-grinding for 15 minutes, and obtain a mixture with a particle size of less than 1 mm, including: 0.8-1 mm 15%, 0.5-0.8 m 20%, 0.1-0.5 mm 30%, less than 0.1 mm 35%;

[0082] 4) Use 630T hollow brick press to press into checkered brick shape;

[0083] 5) Under room temperature conditions, place the checkered brick mold naturally for 24 hours and then calcine it in a tunnel kiln. First, slowly heat it to 220℃ and keep it constant for 1.8 hours. After the natural water in the brick is drained, increase the calcination rate by 5℃ / hour, continue to heat it to 800℃, and keep it constant for 3 hours. After the free water and low-melting substances in each mineral are burned out, quickly heat it to 1650℃ and keep it constant for 5 hours. Open the kiln when it cools naturally to 700℃, and finally cool it naturally to room temperature.

[0084] [Comparative Example 1]

[0085] A forsterite checker brick for a hot blast furnace regenerator comprises the following components by weight percentage:

[0086] Natural forsterite 75wt%;

[0087] Clay 17wt%;

[0088] Magnesium oxide 0wt%;

[0089] Magnesium chloride 0wt%;

[0090] Binder 8wt%.

[0091] Furthermore, the binder is a mixture of 20% MgO·SiO2 solution and molasses, wherein the weight percentage of the 20% MgO·SiO2 solution to the molasses is 1.2:1.

[0092] The preparation method is the same as Example 1.

[0093] Compared with Example 1, the addition amount of magnesium oxide and magnesium chloride is 0wt%, that is, the improvement effect of magnesium oxide and magnesium chloride is lacking.

[0094] [Comparative Example 2]

[0095] A forsterite checker brick for a hot blast furnace regenerator comprises the following components by weight percentage:

[0096] Natural forsterite 74wt%;

[0097] Clay 12.5wt%;

[0098] Magnesium oxide 7.5wt%;

[0099] Magnesium chloride 0wt%;

[0100] Binder 6wt%.

[0101] Furthermore, the binder is a mixture of 20% MgO·SiO2 solution and molasses, wherein the weight percentage of the 20% MgO·SiO2 solution to the molasses is 1.2:1.

[0102] The preparation method is the same as Example 1.

[0103] Compared with Example 1, except that the addition amount of magnesium oxide is 7.5wt% and the addition amount of magnesium chloride is 0wt%, the other aspects are basically the same.

[0104] [Comparative Example 3]

[0105] A forsterite checker brick for a hot blast furnace regenerator comprises the following components by weight percentage:

[0106] Natural forsterite 74wt%;

[0107] Clay 18wt%;

[0108] Magnesium oxide 0wt%;

[0109] Magnesium chloride 2wt%;

[0110] Binder 6wt%.

[0111] Furthermore, the binder is a mixture of 20% MgO·SiO2 solution and molasses, wherein the weight percentage of the 20% MgO·SiO2 solution to the molasses is 1.2:1.

[0112] The preparation method is the same as Example 1.

[0113] Compared with Example 1, except that the addition amount of magnesium oxide is 0wt% and the addition amount of magnesium chloride is 2wt%, the other aspects are basically the same.

[0114] According to conventional testing methods, the performance indicators of the above embodiments and comparative examples, such as apparent porosity, bulk density, room temperature compressive strength, and 0.2 MPa load softening temperature, are shown in Table 1.

[0115] Table 1

[0116]

[0117] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A forsterite checker brick for a hot blast stove regenerator, characterized in that: The components include the following by weight percentage: Natural forsterite 70-75wt%; Clay 10~20wt%; Magnesium oxide 5-10wt%; Magnesium chloride 1-3wt%; Binder 4~8wt%.

2. The forsterite checker brick for hot blast stove regenerator according to claim 1, characterized in that: The binder is a mixture of 20% MgO·SiO2 solution and molasses, wherein the weight percentage of the 20% MgO·SiO2 solution to the molasses is 1.5-2.5:

1.

3. The forsterite checker brick for hot blast stove regenerator according to claim 1, characterized in that: The components include the following by weight percentage: Natural forsterite 73wt%; Clay 12.5wt%; Magnesium oxide 7.5wt%; Magnesium chloride 2wt%; Binder 5wt%.

4. The forsterite checker brick for hot blast stove regenerator according to claim 1, characterized in that: The binder is a mixture of 20% MgO·SiO2 solution and molasses, wherein the weight percentage of the 20% MgO·SiO2 solution to the molasses is 2:

1.

5. The forsterite checker brick for hot blast stove regenerator according to claim 1, characterized in that: The calcination system of the checker brick blank made by mixing and grinding the components weighed by weight percentage is as follows: 1) Under room temperature, place the checkered brick mold naturally for 24 hours and then calcine it in a tunnel kiln. First, slowly heat it to 250°C and keep it at a constant temperature for 2.2 hours; 2) Increase the calcination rate by 5°C / hour, continue to raise the temperature to 750°C, and keep the temperature constant for 2.5 hours; 3) Rapidly heat to 1600°C and keep constant temperature for 5 hours; 4) Open the kiln when it cools naturally to 700℃, and finally cool naturally to room temperature.

6. The forsterite checker brick for hot blast stove regenerator according to claim 1, characterized in that: The particle size of the mixture obtained by mixing and grinding the components weighed by weight percentage is less than 1 mm, of which: 0.8-1 mm accounts for 15%, 0.5-0.8 mm accounts for 20%, 0.1-0.5 mm accounts for 30%, and less than 0.1 mm accounts for 35%.

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