CN113121248A - VD furnace cover castable composite lining and preparation method thereof - Google Patents

Abstract

A VD furnace cover castable composite lining comprises a base layer castable layer and a high-temperature layer castable layer which are formed by adopting base layer castable and high-temperature layer castable moulds to vibrate or cast; the base castable comprises the following raw materials in percentage by mass: 60-70 wt% of corundum particles, 10-20 wt% of corundum fine powder, 10-20 wt% of alumina fine powder, 2-5 wt% of silicon powder, 3-6 wt% of aluminate cement, 1-3 wt% of stainless steel fibers, 0.1 wt% of sodium tripolyphosphate, 0.1 wt% of metal aluminum powder, 0.02-0.1 wt% of propylene glycol alginate and 3.5-7 wt% of water; the high-temperature layer castable comprises the following raw materials in percentage by mass: 60-70 wt% of corundum particles, 10-15 wt% of corundum fine powder, 5-10 wt% of spinel fine powder, 5-13 wt% of magnesia fine powder, 1-3 wt% of prefabricated powder, 3-10 wt% of prefabricated particles, 1-4 wt% of aluminate cement, 1-2 wt% of stainless steel fibers, 0.1 wt% of sodium tripolyphosphate, 0.1 wt% of metal aluminum powder and 3.5-6 wt% of water; the integral thermal shock stability can be improved, and the furnace cover has no phenomena of cracking, stripping, block falling and the like during the use.

Description

VD furnace cover castable composite lining and preparation method thereof

Technical Field

The invention belongs to the technical field of high-temperature refractory materials. In particular to a VD furnace cover castable composite lining and a preparation method thereof.

Background

The VD refining method is a molten steel vacuum treatment method in which primary molten steel of an electric furnace and a converter is placed in a closed tank for vacuumizing, and argon is blown to the bottom of a steel ladle for stirring. Melting and primary blowing are carried out in an electric furnace and a converter, and then the molten steel is placed in a vacuum tank to be stirred by bottom blowing argon and vacuum degassing to obtain pure molten steel. Compared with other refining equipment, the VD furnace mainly completes the tasks of degassing, stirring and the like. In the VD furnace equipment configuration, the furnace cover mainly plays the roles of shielding the high-temperature radiation of molten steel in the vacuum degassing process and preventing steel slag from splashing, protecting other configuration equipment from being damaged and ensuring the smooth operation of the vacuum degassing refining process. In addition, the heat in the furnace can be shielded, the heat loss is reduced, the heat preservation is realized, and the temperature drop of the molten steel in the vacuum degassing process is weakened. Therefore, in the use of the furnace cover, the working environment is severe, and the furnace cover mainly bears the effects of high-temperature airflow scouring, high-temperature slag splashing, chemical erosion of high-temperature gas and mechanical vibration, so that the steel shell is deformed, the internal refractory material falls off and blocks fall off, the service life of the furnace cover is reduced, the downtime of the VD furnace is long, and the utilization rate is reduced. Aiming at the situations, the prior art carries out a great deal of work on the aspects of the shape of the furnace cover, the matching of the lining, the combination of the refractory material and the steel shell and the like to improve the service performance of the furnace cover of the VD furnace, but the action effect is not obvious.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and aims to provide a VD furnace lid castable composite lining and a preparation method thereof. Therefore, the prepared VD furnace cover castable composite lining has high overall thermal shock stability, and the furnace cover does not crack, peel off, fall off and the like during use, thereby being beneficial to the smooth operation of the refining process.

The VD furnace cover castable composite lining comprises a base layer castable layer and a high-temperature layer castable layer; and the base pouring material layer and the high-temperature layer pouring material layer are respectively formed by adopting base pouring materials and high-temperature layer pouring materials through mould vibration or pouring.

The base castable comprises the following raw materials in percentage by mass: 60-70 wt% of corundum particles, 10-20 wt% of corundum fine powder, 10-20 wt% of alumina fine powder, 2-5 wt% of silicon powder, 3-6 wt% of aluminate cement, 1-3 wt% of stainless steel fibers, 0.1 wt% of sodium tripolyphosphate, 0.1 wt% of metal aluminum powder, 0.02-0.1 wt% of propylene glycol alginate and 3.5-7 wt% of water.

The high-temperature layer castable comprises the following raw materials in percentage by mass: 60-70 wt% of corundum particles, 10-15 wt% of corundum fine powder, 5-10 wt% of spinel fine powder, 5-13 wt% of magnesia fine powder, 1-3 wt% of prefabricated powder, 3-10 wt% of prefabricated particles, 1-4 wt% of aluminate cement, 1-2 wt% of stainless steel fibers, 0.1 wt% of sodium tripolyphosphate, 0.1 wt% of metal aluminum powder and 3.5-6 wt% of water.

The prefabricated powder and the prefabricated particles are prepared by uniformly mixing 5-10 wt% of glass powder, 10-20 wt% of silicon carbide powder, 60-70 wt% of silicon carbide particles, 5-10 wt% of silicon micropowder, 2-3 wt% of glucose and 3-5 wt% of water according to the proportion, performing compression molding under the condition of 100-120MPa, performing heat treatment at the temperature of 650-720 ℃ for 3 hours, cooling to room temperature along with a furnace, crushing and screening to obtain prefabricated powder with the particle size of less than 0.088mm and prefabricated particles with the particle size of 0.088-2 mm.

The thickness of the high-temperature layer casting material layer is 1/2-2/3 of the whole thickness of the furnace cover, and the thickness of the base layer casting material layer is 1/2-1/3 of the whole thickness of the furnace cover.

SiO in the glass powder₂The content of (B) is 50-70 wt%, Na₂O content of 2-10 wt%, K₂The content of O is 3-8 wt%, the content of CaO is 5-15 wt%, the content of MgO is 2-10 wt%, and the particle size of the glass powder is less than 0.045 mm.

The content of SiC in the silicon carbide is more than 97 wt%, the granularity of the silicon carbide powder is less than 0.088mm, and the granularity of the silicon carbide particle is 0.088-1 mm. The corundum is brown corundum or white corundum, and Al in the corundum₂O₃The content of the corundum is more than 95 wt%, the granularity of the corundum particles is 1-10mm, and the granularity of the corundum fine powder is less than 0.088 mm.

The stainless steel fiber is a nickel-containing heat-resistant steel fiber (310#), the cross section of the stainless steel fiber is in a crescent shape, and the size of the stainless steel fiber is (0.1-0.2mm) × (0.8-1.2mm) × (38-42 mm). The granularity of the metal aluminum powder is less than 0.088 mm.

Al in the alumina₂O₃In an amount of 85-88 wt%, Fe₂O₃The content of alumina is less than 2 wt%, and the particle size of the alumina fine powder is less than 0.088 mm. SiO in the silicon micro powder₂Is greater than 92 wt%; al in the aluminate cement₂O₃Is greater than 65 wt%; the MgO content in the magnesite fine powder is more than 94 wt%, and the particle size is less than 0.088 mm; al in the spinel fine powder₂O₃The content of (A) is more than 68 wt%, the content of MgO is more than 27 wt%, and the particle size is less than 0.088 mm.

The preparation method of the VD furnace cover castable composite lining comprises the following steps:

(1) preparing prefabricated powder and prefabricated particles;

(2) preparing a base pouring material layer; uniformly stirring the mixed base castable, putting the mixture into a mould for vibration molding, and standing the mixture for 2 hours at room temperature to obtain the base castable;

(3) preparing a high-temperature layer casting material layer; uniformly stirring the mixed high-temperature castable, pouring the castable on the base castable, and performing vibration molding;

(4) standing for 24 hours at room temperature, and then carrying out heat treatment at 110 ℃ for 24 hours to obtain the VD furnace cover castable composite lining.

Due to the adoption of the technical scheme, compared with the prior art, the invention has the following positive effects:

the composite castable disclosed by the invention is based on the thermal and mechanical properties of different raw materials and the influence of technological parameters such as particles, proportion and temperature on the structure and performance of the castable, silicon carbide powder, silicon carbide particles and a small amount of glass powder are compounded, and under the auxiliary action of the raw materials such as silicon micropowder and the like, the silicon carbide powder and the silicon carbide particles are appropriately wrapped by heat treatment to prepare prefabricated powder and prefabricated particles. After the high-temperature layer casting material is introduced, the unique structure of the prefabricated powder and the particles improves the oxidation resistance of the silicon carbide in the high-temperature use process, so that the silicon carbide can play the characteristics of large hardness, low thermal expansion coefficient and the like in the high-temperature use process of the product; moderate sintering is formed among different raw materials, and the heat transfer process of the materials is optimized, so that the prepared high-temperature layer castable has higher thermal shock stability.

By adjusting the preparation process parameters, and combining the characteristics that the high-temperature layer casting material bears high-temperature heat, mechanical and chemical impact, and the base layer casting material part is corroded and damaged to a lower extent, the invention designs the gradient distribution of the two parts of layer linings in the aspects of structure, thermal property, mechanical property and the like, thereby avoiding interface mismatch caused by overlarge difference between the high-temperature layer and the base layer in structure and performance; the introduction of the prefabricated powder and the prefabricated particles into the high-temperature layer casting material and the small amount of glass phase coated on the surface of the silicon carbide enable the silicon carbide and other raw materials to form proper ceramic combination, thereby reducing the oxidation of the silicon carbide at high temperature and being beneficial to adjusting the heat transfer process of the material; by utilizing the high-temperature reactivity among different raw materials and adjusting the preparation process parameters, when the high-temperature castable is used at high temperature, proper sintering is formed among different raw materials, and uniformly distributed grain embedding structures such as corundum, spinel, silicon carbide and the like are formed in the high-temperature castable. Therefore, compared with the prior art, the VD furnace cover castable composite lining layer prepared by the invention has excellent mechanical property.

The VD furnace lid castable composite lining prepared by the preparation method has the characteristics of high mechanical strength (the normal temperature breaking strength of the high-temperature layer castable is greater than 27MPa after being subjected to a 1550 ℃ heat treatment for 3 hours, and the high temperature breaking strength (1450 ℃ and 0.5 hour) is greater than 22 MPa), the normal temperature breaking strength of the base castable is greater than 14MPa after being subjected to a 1500 ℃ heat treatment for 3 hours, the thermal shock stability is high (the high-temperature layer castable is subjected to 1100 ℃ water cooling for more than 26 times, and the base castable is subjected to 1100 ℃ water cooling for more than 25 times), and the like, so that the prepared VD furnace lid castable composite lining has no phenomena of furnace lid cracking, stripping, block falling and the like during the use, and is favorable for the smooth implementation.

Detailed Description

The invention is further described with reference to specific embodiments, without limiting its scope.

Example 1

(1) Mixing 10 wt% of glass powder, 20 wt% of silicon carbide powder, 60 wt% of silicon carbide particles, 5 wt% of silicon micropowder, 2 wt% of glucose and 3 wt% of water uniformly according to a proportion, pressing and molding under the condition of 120MPa, placing at 650 ℃ for heat treatment for 3 hours, cooling to room temperature along with a furnace, crushing and screening to obtain prefabricated powder with the granularity of less than 0.088mm and prefabricated particles with the granularity of 0.088-2 mm.

(2) 55 wt% of brown corundum particles, 15 wt% of brown corundum fine powder, 14 wt% of alumina fine powder, 2 wt% of silicon micro powder, 6 wt% of aluminate cement and 2 wt% of stainless steel fibers, and 0.1 wt% of sodium tripolyphosphate, 0.1 wt% of metal aluminum powder, 0.03 wt% of propylene glycol alginate and 5.77 wt% of water are added, uniformly stirred, placed into a mold for vibration molding, and kept stand for 2 hours at room temperature to obtain a base pouring material layer.

(3) And preparing a high-temperature layer casting material layer. 55 wt% of brown corundum particles, 10 wt% of brown corundum fine powder, 5 wt% of spinel fine powder, 9 wt% of magnesia fine powder, 3 wt% of prefabricated powder, 6 wt% of prefabricated particles, 4 wt% of aluminate cement, 2 wt% of stainless steel fibers, 0.1 wt% of sodium tripolyphosphate, 0.1 wt% of metal aluminum powder and 5.8 wt% of water are uniformly stirred according to the proportion, the mixture is poured on a base layer pouring material, the thickness of the part of pouring material is controlled to be 1.5 times of that of the base layer pouring material, and the mixture is vibrated and molded.

(4) Standing at room temperature for 24 hours and performing heat treatment at 110 ℃ for 24 hours to obtain the VD furnace cover castable composite lining layer consisting of the base castable layer and the high-temperature layer castable layer.

Example 2

Firstly, uniformly mixing 10 wt% of glass powder, 16 wt% of silicon carbide powder, 60 wt% of silicon carbide particles, 9 wt% of silicon micropowder, 2 wt% of glucose and 3 wt% of water according to a proportion, performing compression molding under the condition of 120MPa, performing heat treatment at 700 ℃ for 3 hours, cooling to room temperature along with a furnace, crushing and screening to obtain prefabricated powder with the granularity of less than 0.088mm and prefabricated particles with the granularity of 0.088-2 mm.

Secondly, 64 wt% of brown corundum particles, 10 wt% of brown corundum fine powder, 10 wt% of alumina fine powder, 3 wt% of silicon powder, 6 wt% of aluminate cement, 2 wt% of stainless steel fibers, 0.1 wt% of sodium tripolyphosphate, 0.1 wt% of metal aluminum powder, 0.07 wt% of propylene glycol alginate and 4.73 wt% of water are added, the mixture is uniformly stirred, placed into a mold for vibration molding, and kept stand for 2 hours at room temperature to obtain a base pouring material layer.

And thirdly, preparing a casting material layer of the corresponding high-temperature layer. 55 wt% of brown corundum particles, 10 wt% of brown corundum fine powder, 5 wt% of spinel fine powder, 9 wt% of magnesia fine powder, 3 wt% of prefabricated powder, 6 wt% of prefabricated particles, 4 wt% of aluminate cement, 2 wt% of stainless steel fibers, 0.1 wt% of sodium tripolyphosphate, 0.1 wt% of metal aluminum powder and 5.8 wt% of water are uniformly stirred according to the proportion, the mixture is poured on a base layer pouring material, the thickness of the part of pouring material is controlled to be 1.5 times of that of the base layer pouring material, and the mixture is vibrated and molded.

And fourthly, standing at room temperature for 24 hours and performing heat treatment at 110 ℃ for 24 hours to obtain the VD furnace cover castable composite lining layer consisting of the base layer castable layer and the high-temperature layer castable layer.

Example 3

Firstly, uniformly mixing 6 wt% of glass powder, 20 wt% of silicon carbide powder, 63 wt% of silicon carbide particles, 6 wt% of silicon micropowder, 2 wt% of glucose and 3 wt% of water according to a proportion, performing compression molding under the condition of 120MPa, performing heat treatment at 720 ℃ for 3 hours, cooling to room temperature along with a furnace, crushing and screening to obtain prefabricated powder with the granularity of less than 0.088mm and prefabricated particles with the granularity of 0.088-2 mm.

And secondly, uniformly stirring 55 wt% of brown corundum particles, 15 wt% of brown corundum fine powder, 12 wt% of alumina fine powder, 5 wt% of silicon powder, 6 wt% of aluminate cement, 2 wt% of stainless steel fibers, 0.1 wt% of sodium tripolyphosphate, 0.1 wt% of metal aluminum powder, 0.07 wt% of propylene glycol alginate and 4.73 wt% of water, placing the mixture into a mold for vibration molding, and standing the mixture at room temperature for 2 hours to obtain a base pouring material layer.

And thirdly, preparing a casting material layer of the corresponding high-temperature layer. The method comprises the steps of uniformly stirring 55 wt% of brown corundum particles, 10 wt% of brown corundum fine powder, 5 wt% of spinel fine powder, 9 wt% of magnesia fine powder, 3 wt% of prefabricated powder, 7 wt% of prefabricated particles, 4 wt% of aluminate cement, 2 wt% of stainless steel fibers, 0.1 wt% of sodium tripolyphosphate, 0.1 wt% of metal aluminum powder and 4.8 wt% of water according to a proportion, pouring the mixture on a base layer pouring material, controlling the thickness of the part of pouring material to be 1.5 times of that of the base layer pouring material, and carrying out vibration molding.

And fourthly, standing for 24 hours at room temperature and carrying out heat treatment at 110 ℃ for 24 hours to obtain the VD furnace cover castable composite lining.

Example 4

Firstly, uniformly mixing 10 wt% of glass powder, 11 wt% of silicon carbide powder, 63 wt% of silicon carbide particles, 10 wt% of silicon micropowder, 3 wt% of glucose and 3 wt% of water according to a proportion, performing compression molding under the condition of 120MPa, performing heat treatment at 700 ℃ for 3 hours, cooling to room temperature along with a furnace, crushing and screening to obtain prefabricated powder with the granularity of less than 0.088mm and prefabricated particles with the granularity of 0.088-2 mm.

And secondly, uniformly stirring 55 wt% of brown corundum particles, 17 wt% of brown corundum fine powder, 14 wt% of alumina fine powder, 3 wt% of silicon powder, 4 wt% of aluminate cement, 2 wt% of stainless steel fibers, 0.1 wt% of sodium tripolyphosphate, 0.1 wt% of metal aluminum powder, 0.08 wt% of propylene glycol alginate and 4.72 wt% of water, placing the mixture into a mold for vibration molding, and standing the mixture at room temperature for 2 hours to obtain a base pouring material layer.

And thirdly, preparing the high-temperature layer casting material. 55 wt% of brown corundum particles, 10 wt% of brown corundum fine powder, 5 wt% of spinel fine powder, 9 wt% of magnesia fine powder, 3 wt% of prefabricated powder, 7 wt% of prefabricated particles, 4 wt% of aluminate cement, 2 wt% of stainless steel fibers, 0.1 wt% of sodium tripolyphosphate, 0.1 wt% of metal aluminum powder and 4.8 wt% of water are uniformly stirred according to the proportion and poured on a base layer pouring material, the thickness of the part of pouring material is controlled to be 1.5 times of that of the base layer pouring material, and a layer is formed in a vibration mode.

And fourthly, standing for 24 hours at room temperature and performing heat treatment at 110 ℃ for 24 hours to obtain the VD furnace cover castable composite lining.

Example 5

Firstly, uniformly mixing 10 wt% of glass powder, 11 wt% of silicon carbide powder, 63 wt% of silicon carbide particles, 10 wt% of silicon micropowder, 3 wt% of glucose and 3 wt% of water according to a proportion, performing compression molding under the condition of 120MPa, performing heat treatment at 700 ℃ for 3 hours, cooling to room temperature along with a furnace, crushing and screening to obtain prefabricated powder with the granularity of less than 0.088mm and prefabricated particles with the granularity of 0.088-2 mm.

And secondly, uniformly stirring 55 wt% of brown corundum particles, 13 wt% of brown corundum fine powder, 13 wt% of alumina fine powder, 3 wt% of silicon micropowder, 6 wt% of aluminate cement, 3 wt% of stainless steel fibers, 0.1 wt% of sodium tripolyphosphate, 0.1 wt% of metal aluminum powder, 0.09 wt% of propylene glycol alginate and 6.71 wt% of water, placing the mixture into a mold for vibration molding, and standing the mixture at room temperature for 2 hours to obtain a base pouring material layer.

And thirdly, preparing a casting material layer of the corresponding high-temperature layer. 57 wt% of brown corundum particles, 10 wt% of brown corundum fine powder, 5 wt% of spinel fine powder, 8 wt% of magnesia fine powder, 3 wt% of prefabricated powder, 5 wt% of prefabricated particles, 4 wt% of aluminate cement, 2 wt% of stainless steel fibers, 0.1 wt% of sodium tripolyphosphate, 0.1 wt% of metal aluminum powder and 5.8 wt% of water are uniformly stirred according to the proportion and poured on a base layer pouring material, the thickness of the part of pouring material is controlled to be 1.5 times of that of the base layer pouring material, and the pouring material is formed in a vibration mode.

And fourthly, standing for 24 hours at room temperature and carrying out heat treatment at 110 ℃ for 24 hours to obtain the VD furnace cover castable composite lining.

Example 6

Firstly, uniformly mixing 10 wt% of glass powder, 11 wt% of silicon carbide powder, 63 wt% of silicon carbide particles, 10 wt% of silicon micropowder, 3 wt% of glucose and 3 wt% of water according to a proportion, performing compression molding under the condition of 120MPa, performing heat treatment at 700 ℃ for 3 hours, cooling to room temperature along with a furnace, crushing and screening to obtain prefabricated powder with the granularity of less than 0.088mm and prefabricated particles with the granularity of 0.088-2 mm.

And secondly, uniformly stirring 55 wt% of brown corundum particles, 18 wt% of brown corundum fine powder, 10 wt% of alumina fine powder, 3 wt% of silicon powder, 6 wt% of aluminate cement, 2 wt% of stainless steel fibers, 0.1 wt% of sodium tripolyphosphate, 0.1 wt% of metal aluminum powder, 0.04 wt% of propylene glycol alginate and 5.76 wt% of water, placing the mixture into a mold for vibration molding, and standing the mixture at room temperature for 2 hours to obtain a base pouring material layer.

And thirdly, preparing a casting material layer of the corresponding high-temperature layer. 57 wt% of brown corundum particles, 10 wt% of brown corundum fine powder, 5 wt% of spinel fine powder, 9 wt% of magnesia fine powder, 1 wt% of prefabricated powder, 7 wt% of prefabricated particles, 4 wt% of aluminate cement, 2 wt% of stainless steel fibers, 0.1 wt% of sodium tripolyphosphate, 0.1 wt% of metal aluminum powder and 4.8 wt% of water are uniformly stirred according to the proportion and poured on a base layer pouring material, the thickness of the part of pouring material is controlled to be 1.5 times of that of the base layer pouring material, and the pouring material is formed in a vibration mode.

And fourthly, standing for 24 hours at room temperature and carrying out heat treatment at 110 ℃ for 24 hours to obtain the VD furnace cover castable composite lining.

Example 7

Firstly, uniformly mixing 10 wt% of glass powder, 11 wt% of silicon carbide powder, 63 wt% of silicon carbide particles, 10 wt% of silicon micropowder, 3 wt% of glucose and 3 wt% of water according to a proportion, performing compression molding under the condition of 120MPa, performing heat treatment at 700 ℃ for 3 hours, cooling to room temperature along with a furnace, crushing and screening to obtain prefabricated powder with the granularity of less than 0.088mm and prefabricated particles with the granularity of 0.088-2 mm.

And secondly, uniformly stirring 55 wt% of brown corundum particles, 18 wt% of white corundum fine powder, 10 wt% of alumina fine powder, 3 wt% of silicon powder, 6 wt% of aluminate cement, 2 wt% of stainless steel fibers, 0.1 wt% of sodium tripolyphosphate, 0.1 wt% of metal aluminum powder, 0.06 wt% of propylene glycol alginate and 5.74 wt% of water, placing the mixture into a mold for vibration molding, and standing the mixture at room temperature for 2 hours to obtain a base pouring material layer.

And thirdly, preparing a casting material layer of the corresponding high-temperature layer. 55 wt% of brown corundum particles, 10 wt% of brown corundum fine powder, 9 wt% of spinel fine powder, 5 wt% of magnesia fine powder, 3 wt% of prefabricated powder, 7 wt% of prefabricated particles, 4 wt% of aluminate cement, 2 wt% of stainless steel fibers, 0.1 wt% of sodium tripolyphosphate, 0.1 wt% of metal aluminum powder and 4.8 wt% of water are uniformly stirred according to the proportion and poured on a base layer pouring material, the thickness of the part of pouring material is controlled to be 1.5 times of that of the base layer pouring material, and the pouring material is formed in a vibration mode.

And fourthly, standing for 24 hours at room temperature and performing heat treatment at 110 ℃ for 24 hours to obtain the VD furnace cover castable composite lining.

Example 8

Firstly, uniformly mixing 10 wt% of glass powder, 11 wt% of silicon carbide powder, 63 wt% of silicon carbide particles, 10 wt% of silicon micropowder, 3 wt% of glucose and 3 wt% of water according to a proportion, performing compression molding under the condition of 120MPa, performing heat treatment at 700 ℃ for 3 hours, cooling to room temperature along with a furnace, crushing and screening to obtain prefabricated powder with the granularity of less than 0.088mm and prefabricated particles with the granularity of 0.088-2 mm.

And secondly, uniformly stirring 62 wt% of white corundum particles, 10 wt% of white corundum fine powder, 10 wt% of alumina fine powder, 3 wt% of silicon powder, 6 wt% of aluminate cement, 2 wt% of stainless steel fibers, 0.1 wt% of sodium tripolyphosphate, 0.1 wt% of metal aluminum powder, 0.04 wt% of propylene glycol alginate and 6.86 wt% of water, placing the mixture into a mold for vibration molding, and standing the mixture at room temperature for 2 hours to obtain a base pouring material layer.

And thirdly, preparing a casting material layer of the corresponding high-temperature layer. 55 wt% of brown corundum particles, 15 wt% of brown corundum fine powder, 5 wt% of spinel fine powder, 5 wt% of magnesia fine powder, 2 wt% of prefabricated powder, 7 wt% of prefabricated particles, 4 wt% of aluminate cement, 2 wt% of stainless steel fibers, 0.1 wt% of sodium tripolyphosphate, 0.1 wt% of metal aluminum powder and 4.8 wt% of water are uniformly stirred according to the proportion and poured on a base layer pouring material, the thickness of the part of pouring material is controlled to be 1.5 times of that of the base layer pouring material, and the pouring material is formed in a vibration mode.

And fourthly, standing for 24 hours at room temperature and carrying out heat treatment at 110 ℃ for 24 hours to obtain the VD furnace cover castable composite lining.

Example 9

Firstly, uniformly mixing 10 wt% of glass powder, 11 wt% of silicon carbide powder, 63 wt% of silicon carbide particles, 10 wt% of silicon micropowder, 3 wt% of glucose and 3 wt% of water according to a proportion, performing compression molding under the condition of 120MPa, performing heat treatment at 700 ℃ for 3 hours, cooling to room temperature along with a furnace, crushing and screening to obtain prefabricated powder with the granularity of less than 0.088mm and prefabricated particles with the granularity of 0.088-2 mm.

And secondly, mixing 65 wt% of white corundum particles, 10 wt% of white corundum fine powder, 10 wt% of alumina fine powder, 3 wt% of silicon powder, 4 wt% of aluminate cement, 1 wt% of stainless steel fibers, 0.1 wt% of sodium tripolyphosphate, 0.1 wt% of metal aluminum powder, 0.03 wt% of propylene glycol alginate and 6.77 wt% of water, uniformly stirring, placing the mixture into a mold for vibration molding, and standing for 2 hours at room temperature to obtain a base pouring material layer.

And thirdly, preparing a casting material layer of the corresponding high-temperature layer. 62 weight percent of brown corundum particles, 10 weight percent of brown corundum fine powder, 5 weight percent of spinel fine powder, 5 weight percent of magnesia fine powder, 2 weight percent of prefabricated powder, 5 weight percent of prefabricated particles, 4 weight percent of aluminate cement, 2 weight percent of stainless steel fibers, 0.1 weight percent of sodium tripolyphosphate, 0.1 weight percent of metal aluminum powder and 4.8 weight percent of water are uniformly stirred according to the proportion and poured on a base layer pouring material, the thickness of the part of pouring material is controlled to be 1.5 times of that of the base layer pouring material, and the pouring material is formed in a vibration mode.

And fourthly, standing for 24 hours at room temperature and carrying out heat treatment at 110 ℃ for 24 hours to obtain the VD furnace cover castable composite lining.

Example 10

Firstly, uniformly mixing 10 wt% of glass powder, 11 wt% of silicon carbide powder, 63 wt% of silicon carbide particles, 10 wt% of silicon micropowder, 3 wt% of glucose and 3 wt% of water according to a proportion, performing compression molding under the condition of 120MPa, performing heat treatment at 700 ℃ for 3 hours, cooling to room temperature along with a furnace, crushing and screening to obtain prefabricated powder with the granularity of less than 0.088mm and prefabricated particles with the granularity of 0.088-2 mm.

And secondly, uniformly stirring 55 wt% of brown corundum particles, 10 wt% of brown corundum fine powder, 18 wt% of alumina fine powder, 3 wt% of silicon powder, 6 wt% of aluminate cement, 2 wt% of stainless steel fibers, 0.1 wt% of sodium tripolyphosphate, 0.1 wt% of metal aluminum powder, 0.04 wt% of propylene glycol alginate and 5.76 wt% of water, placing the mixture into a mold for vibration molding, and standing the mixture at room temperature for 2 hours to obtain a base pouring material layer.

And thirdly, preparing a casting material layer of the corresponding high-temperature layer. 55 wt% of brown corundum particles, 10 wt% of brown corundum fine powder, 5 wt% of spinel fine powder, 12 wt% of magnesia fine powder, 1 wt% of prefabricated powder, 5 wt% of prefabricated particles, 4 wt% of aluminate cement, 2 wt% of stainless steel fibers, 0.1 wt% of sodium tripolyphosphate, 0.1 wt% of metal aluminum powder and 5.8 wt% of water are uniformly stirred according to the proportion and poured on a base layer pouring material, the thickness of the part of pouring material is controlled to be 1.5 times of that of the base layer pouring material, and the pouring material is formed in a vibration mode.

And fourthly, standing for 24 hours at room temperature and carrying out heat treatment at 110 ℃ for 24 hours to obtain the VD furnace cover castable composite lining.

Example 11

Firstly, uniformly mixing 10 wt% of glass powder, 11 wt% of silicon carbide powder, 63 wt% of silicon carbide particles, 10 wt% of silicon micropowder, 3 wt% of glucose and 3 wt% of water according to a proportion, performing compression molding under the condition of 120MPa, performing heat treatment at 700 ℃ for 3 hours, cooling to room temperature along with a furnace, crushing and screening to obtain prefabricated powder with the granularity of less than 0.088mm and prefabricated particles with the granularity of 0.088-2 mm.

And secondly, uniformly stirring 55 wt% of white corundum particles, 15 wt% of white corundum fine powder, 13 wt% of alumina fine powder, 3 wt% of silicon powder, 5 wt% of aluminate cement, 2 wt% of stainless steel fibers, 0.1 wt% of sodium tripolyphosphate, 0.1 wt% of metal aluminum powder, 0.03 wt% of propylene glycol alginate and 6.77 wt% of water, placing the mixture into a mold for vibration molding, and standing the mixture at room temperature for 2 hours to obtain a base pouring material layer.

And thirdly, preparing a casting material layer of the corresponding high-temperature layer. 57 wt% of white corundum particles, 10 wt% of white corundum fine powder, 5 wt% of spinel fine powder, 8 wt% of magnesia fine powder, 3 wt% of prefabricated powder, 5 wt% of prefabricated particles, 4 wt% of aluminate cement, 2 wt% of stainless steel fibers, 0.1 wt% of sodium tripolyphosphate, 0.1 wt% of metal aluminum powder and 5.8 wt% of water are uniformly stirred according to the proportion and poured on a base layer pouring material, the thickness of the part of pouring material is controlled to be 1.5 times of that of the base layer pouring material, and the part of pouring material is vibrated and molded.

And fourthly, standing for 24 hours at room temperature and carrying out heat treatment at 110 ℃ for 24 hours to obtain the VD furnace cover castable composite lining.

The VD furnace lid castable composite lining prepared in each example is tested by sampling, and the obtained properties are listed in Table 1.

The invention relates to a method for testing main performance indexes of a product, which comprises the following steps:

normal temperature flexural strength: the high-temperature layer castable layer and the base layer castable layer prepared by the preparation method are respectively sampled and tested according to a test method of the normal-temperature rupture strength of the refractory material (the standard of the black metallurgy industry of the people's republic of China), and the loading rate is 0.15MPa/s +/-0.015 MPa/s. The performance index provided by the embodiment of the invention is that a sample is respectively subjected to heat treatment for 3 hours at 1550 ℃ (high temperature layer casting material) and 1500 ℃ (base layer casting material), cooled to room temperature, and then tested for normal temperature rupture strength according to the industry standard.

High-temperature flexural strength: the high-temperature layer castable layer prepared by the preparation method is sampled and tested according to a high-temperature flexural strength test method (the standard of the black metallurgy industry of the people's republic of China) of the refractory material, and the loading rate is (0.15 +/-0.015) MPa/s. The performance index provided by the embodiment of the invention is that after the sample is subjected to heat preservation at 1450 ℃ for 0.5 hour, the high-temperature breaking strength is tested according to the industrial standard.

Thermal shock stability: the high-temperature layer castable layer and the base layer castable layer prepared by the preparation method are respectively sampled and tested according to a refractory castable thermal shock resistance test method (water quenching method) (the standard of the black metallurgy industry of the people's republic of China). The performance index provided by the embodiment of the invention is that the preheating temperature of the sample is 1100 ℃.

TABLE 1 comparison of the properties of the composite lining of VD furnace lid castable in accordance with various embodiments of the present invention

Description of the drawings: through the change of the proportion of the prefabricated powder and the proportion change of the base castable and the high-temperature castable, the experimental result shows that the VD furnace cover castable composite lining layer prepared by the preparation method has the characteristics of high mechanical strength (the normal-temperature breaking strength is greater than 27MPa after the high-temperature layer castable is subjected to heat treatment at 1550 ℃ for 3 hours, the high-temperature breaking strength (1450 ℃ and 0.5 hour) is greater than 22 MPa), high thermal shock stability (the normal-temperature breaking strength is greater than 14MPa after the high-temperature layer castable is subjected to heat treatment at 1500 ℃ for 3 hours), no phenomena of furnace cover cracking, stripping, block falling and the like during the use period, and the smooth refining process is facilitated.

Claims (10)

1. A VD furnace cover castable composite lining is characterized by comprising a base layer castable layer and a high-temperature layer castable layer; the base pouring material layer and the high-temperature layer pouring material layer are respectively formed by adopting base pouring materials and high-temperature layer pouring materials through mould vibration or pouring; the base castable comprises the following raw materials in percentage by mass: 60-70 wt% of corundum particles, 10-20 wt% of corundum fine powder, 10-20 wt% of alumina fine powder, 2-5 wt% of silicon powder, 3-6 wt% of aluminate cement, 1-3 wt% of stainless steel fibers, 0.1 wt% of sodium tripolyphosphate, 0.1 wt% of metal aluminum powder, 0.02-0.1 wt% of propylene glycol alginate and 3.5-7 wt% of water; the high-temperature layer castable comprises the following raw materials in percentage by mass: 60-70 wt% of corundum particles, 10-15 wt% of corundum fine powder, 5-10 wt% of spinel fine powder, 5-13 wt% of magnesia fine powder, 1-3 wt% of prefabricated powder, 3-10 wt% of prefabricated particles, 1-4 wt% of aluminate cement, 1-2 wt% of stainless steel fibers, 0.1 wt% of sodium tripolyphosphate, 0.1 wt% of metal aluminum powder and 3.5-6 wt% of water; the prefabricated powder and the prefabricated particles are prepared by uniformly mixing 5-10 wt% of glass powder, 10-20 wt% of silicon carbide powder, 60-70 wt% of silicon carbide particles, 5-10 wt% of silicon micropowder, 2-3 wt% of glucose and 3-5 wt% of water according to the proportion, performing compression molding under the condition of 100-120MPa, performing heat treatment at the temperature of 650-720 ℃ for 3 hours, cooling to room temperature along with a furnace, crushing and screening to obtain prefabricated powder with the particle size of less than 0.088mm and prefabricated particles with the particle size of 0.088-2 mm.

2. The VD furnace cover castable composite lining of claim 1, wherein the thickness of the high-temperature layer castable is 1/2-2/3 of the overall thickness of the furnace cover, and the thickness of the base layer castable is 1/2-1/3 of the overall thickness of the furnace cover.

3. The VD furnace lid castable composite lining layer according to claim 1 or 2, characterized in that SiO in the glass powder₂The content of (B) is 50-70 wt%, Na₂O content of 2-10 wt%, K₂The content of O is 3-8 wt%, the content of CaO is 5-15 wt%, the content of MgO is 2-10 wt%, and the particle size of the glass powder is less than 0.045 mm.

4. The VD furnace cover castable composite lining according to claim 1 or 2, characterized in that the SiC content in the silicon carbide is more than 97 wt%, the particle size of the silicon carbide powder is less than 0.088mm, and the particle size of the silicon carbide particle is 0.088-1 mm.

5. The VD furnace cover castable composite lining according to claim 1 or 2, characterized in that the corundum is brown corundum or white corundum, and Al in the corundum₂O₃The content of the corundum is more than 95 wt%, the granularity of the corundum particles is 1-10mm, and the granularity of the corundum fine powder is less than 0.088 mm.

6. The VD furnace lid castable composite lining according to claim 1 or 2, characterized in that the stainless steel fiber is nickel-containing heat-resistant steel fiber (310#), the cross section is crescent-shaped, and the size of the stainless steel fiber is (0.1-0.2mm) × (0.8-1.2mm) × (38-42 mm).

7. The VD furnace cover castable composite lining according to claim 1 or 2, characterized in that the particle size of the metal aluminum powder is less than 0.088 mm.

8. The composite lining of VD furnace lid castable according to claim 1 or 2, characterized in that Al in alumina is added₂O₃In an amount of 85-88 wt%, Fe₂O₃The content of alumina is less than 2 wt%, and the particle size of the alumina fine powder is less than 0.088 mm.

9. The VD furnace cover castable composite lining layer according to claim 1 or 2, characterized in that SiO in the silica micropowder₂Is greater than 92 wt%; al in the aluminate cement₂O₃Is greater than 65 wt%; the MgO content in the magnesite fine powder is more than 94 wt%, and the particle size is less than 0.088 mm; al in the spinel fine powder₂O₃The content of (A) is more than 68 wt%, the content of MgO is more than 27 wt%, and the particle size is less than 0.088 mm.

10. The preparation method of the VD furnace lid castable composite lining according to claim 1, is characterized in that:

(1) preparing prefabricated powder and prefabricated particles;

(2) preparing a base pouring material layer; uniformly stirring the mixed base castable, putting the mixture into a mould for vibration molding, and standing the mixture for 2 hours at room temperature to obtain the base castable;

(3) preparing a high-temperature layer casting material layer; uniformly stirring the mixed high-temperature castable, pouring the castable on the base castable, and performing vibration molding;

(4) standing for 24 hours at room temperature, and then carrying out heat treatment at 110 ℃ for 24 hours to obtain the VD furnace cover castable composite lining.