Erosion resistant ramming mix for aluminum reduction cells and method of making same

Abstract

Aluminum electrolytic cell anti-erosion ramming material and its preparation method, which is composed of main raw material 86-90%, auxiliary raw material 1-6%, alpha-Al2O3 powder 1-6%, solidified powder 1-6%, dispersing agent 0.1-1%, and solidifying agent 1-6%. All the raw materials are mixed uniformly, and finally sealed for storage. When used on site, it is taken as needed. Not only can it solve the problem of resistance to ice crystal erosion, but also can resist the erosion of aluminum liquid.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of self-sintering shaped refractory, in particular to an aluminum electrolysis cell anti-erosion ramming material and a preparation method thereof. BACKGROUND

[0002] The aluminum electrolysis cell lining can be divided into bottom lining and side lining according to regions. The bottom lining plays a role in supporting the cathode structure and heat preservation, and the side lining mainly plays a role in protecting the surface of the steel metal shell from being eroded by the electrolyte melt. Silicon carbide brick is a new type of furnace building material recently popularized in the non-ferrous industry in China, and was first applied to large pre-baked aluminum electrolysis cells. In recent years, according to the use of enterprises, whether pure silicon carbide bricks or composite side blocks are used, it is found that there are different degrees of fracture and falling off in the production process, and the silicon carbide layer of the composite side block also has a lifting phenomenon.

[0003] Due to the penetration of aluminum liquid, the bottom bulk material will swell after the aluminum electrolysis cell is started and runs for a period of time, which causes the high-alumina brick to be lifted together with the side silicon carbide block above. In severe cases, it can cause the deformation of the cell shell. In particular, during the operation of the aluminum electrolysis cell, it is unavoidable to cause the aluminum liquid to overflow the side silicon carbide brick due to operation problems. If a large amount of aluminum liquid overflows, it may cause the danger of tank leakage. SUMMARY

[0004] The purpose of the present application is to provide an aluminum electrolysis cell anti-erosion ramming material and a preparation method thereof. The SiC main raw material used in the present application is homogeneous and in phase with the side block of the electrolysis cell, which can not only solve the problem of resistance to cryolite erosion, but also resist the scouring of aluminum liquid. The bulk material mainly composed of particles can release stress and buffer the side block of the aluminum electrolysis cell, solving the above two outstanding problems.

[0005] The technical scheme adopted by the present application to achieve the above purpose is as follows: the aluminum electrolysis cell anti-erosion ramming material is composed of main raw material, auxiliary raw material, alpha-Al2O3 powder, solidified powder, dispersing agent and curing agent. The weight percentage of each raw material is as follows: main raw material 86-90%, auxiliary raw material 1-6%, alpha-Al2O3 powder 1-6%, solidified powder 1-6%, curing agent 1-6%, the total weight percentage of the main raw material, auxiliary raw material, alpha-Al2O3 powder, solidified powder and curing agent is 100%, and the weight percentage of the dispersing agent is 0.1-1% of the weight percentage of the main raw material, auxiliary raw material, alpha-Al2O3 powder, solidified powder and curing agent.

[0006] As a further scheme of the present application, the main raw material of the present application is silicon carbide, 3-1mm section 10-25%, 1-0.5mm section 20-35%, 0.5-0mm section 15-30%, and 180 mesh fine powder 20-35%.

[0007] As a further scheme of the present application: the auxiliary raw material of the present application is 1-6% of the total weight percentage of the particle size distribution of 2-1mm and 1-0.2mm of the hollow sphere particles of alumina, and the hollow sphere particles of alumina are selected from one of the segments.

[0008] The solidified powder of the present application is preferably silicon powder with a purity content of more than 93%. The hollow sphere particles of alumina have a purity content of more than 99%.

[0009] The addition of silicon powder in the present application can fill the gaps of the powder, increase the fluidity and later strength of the rammed mass.

[0010] The solidifying agent of the present application is 75 calcium aluminate cement.

[0011] In the present application, the preparation method of the erosion-resistant rammed mass for aluminum electrolysis cell mixes the main raw material, the auxiliary raw material, the alpha-Al2O3 powder, the solidified powder, the dispersing agent, and the solidifying agent, and finally performs sealing preservation. The on-site construction method is: taking and adding the binder water on site as needed, and the water and rammed mass mass ratio is 12-15:100.

[0012] In the aluminum electrolysis cell, a gap of about 1mm is left between the side block and the upper tank extension plate (steel part), and some alpha-Al2O3 powder is generally scattered in it, but during the operation, the side block and the side block have a large hardness, which causes the deformation of the upper tank extension plate (steel part). Now, the design institute increases the gap between the side block and the upper tank extension plate (steel part) to about 1-2mm. In the aluminum electrolysis cell, a gap of about 1-2mm is left between the side block and the upper tank extension plate (steel part), which is to prevent the bottom from expanding and lifting the side block. The main raw material of the present application is silicon carbide, which has the same material and phase as the side block, thereby resisting the erosion of cryolite; a small amount of hollow sphere particles of alumina are added, which effectively releases the stress between the side block and the upper tank extension plate (steel part). The rammed mass of the present application can fill the gap, and the rammed mass of the present application fills the gap, and the strength of the rammed mass is lower than that of the side block, which not only effectively solves the problem of stress release, but also solves the problem of cryolite erosion, effectively avoiding the risk of leakage caused by the aluminum liquid overflowing the side carbonized silicon brick.

[0013] The main raw material silicon carbide added in the application must be required in a large amount, so that the prepared whole body of the mud is uniformly mixed, and the purity can be ensured when used. The high-aluminum fine powder and alpha-Al2O3 powder and silicon powder can play the roles of good construction effect, good late strength, stress release and the like; the cement can play the roles of rapid hardening and meeting the needs of on-site construction. The whole particle size distribution and formula of the application can play the role of resisting the erosion of cryolite. Since the aluminum electrolysis cell will form a furnace side in a short time during operation, the mud and the side block are homogenous and homogeneous materials, which can resist the erosion of the aluminum liquid in the early stage, and there will be no problem after the furnace side is formed, and the erosion of the cryolite can be effectively resisted during the operation of the whole electrolysis cell. Moreover, the mud also needs to have the ability of stress release, and effectively disperses the pressure of the top.

[0014] The main raw material of the application is silicon carbide, which can react with the cryolite molten salt to generate high-viscosity NaAlSiO4, so as to prevent the erosion of the aluminum liquid to the lining.

[0015] The maximum particle size of the main raw material of the application is 2.5 mm, the fine powder is 180 mesh, the maximum particle size of the auxiliary raw material is 2.5 mm, and the fine powder is -180 mesh. On the basis of the three-level gradation of fine powder, medium particle size and large particle size, the content of the fine powder and the medium particle size is greater than that of the large particle size, so that the rammed density can be improved, and the particle segregation can be reduced.

[0016] When the application is used, the rammed mud basically does not contact the aluminum liquid, and the strength is moderate, which is greater than that of the high-aluminum brick and lower than that of the SiC brick, so that the force of the top can be effectively relieved.

[0017] The physical performance index of the mud of the application is as follows: bulk density is greater than or equal to 2.5 g / cm 3 , apparent porosity is less than or equal to 18%, compressive strength at 110℃×24h is greater than or equal to 50 MPa, compressive strength at 900℃×3h is greater than or equal to 90 MPa, bending strength at 110℃×24h is greater than or equal to 20 MPa, bending strength at 900℃×3h is greater than or equal to 25 MPa, and thermal conductivity (W / m·K, 1000℃) is greater than or equal to 6.5. DETAILED DESCRIPTION

[0018] In order to better understand the application, the content of the application will be further illustrated by combining the examples below, but the content of the application is not limited to the examples below.

[0019] Example 1

[0020] The aluminum electrolysis cell erosion-resistant rammed material is composed of 86% of silicon carbide, 2% of alumina hollow sphere, 3% of alpha-Al2O3 powder, 4% of silicon powder, 0.5% of dispersing agent and 4.5% of 75 cement.

[0021] Silicon carbide, 3-1 mm section 17.5%; 1-0.5 mm section 23%; 0.5-0 mm section 29%; 180 mesh fine powder 30.5%.

[0022] The sum of the weight percentage of the 1-0.2 mm particle size distribution of the alumina hollow sphere is 2%.

[0023] The actual test results of this ratio are: SiC≥84%, bulk density≥2.55 g / cm 3 , porosity≤17.5%, compressive strength 110℃X24h≥60Mpa, compressive strength 900℃X3h≥100Mpa, bending strength 110℃X24h≥25Mpa, bending strength 900℃X3h≥35Mpa, thermal conductivity (1000 degrees Celsius)≥6.8 W / M.k

[0024] The construction performance is excellent, and it is basically solidified in 24 hours.

[0025] Example 2

[0026] The erosion-resistant ramming material for aluminum electrolytic cell is composed of 89% silicon carbide, 3% alumina hollow sphere, 2% α-Al2O3 powder, 3% silicon powder, 1% dispersing agent, and 2% 75 cement.

[0027] Silicon carbide, 3-1 mm section 17%; 1-0.5 mm section 22%; 0.5-0 mm section 28%; 180 mesh fine powder 33%.

[0028] The sum of the weight percentage of the 1-0.2 mm particle size distribution of the alumina hollow sphere is 3%.

[0029] The actual test results of this ratio are: SiC≥87%, bulk density≥2.6 g / cm 3 , porosity≤16.5%, compressive strength 110℃X24h≥55Mpa, compressive strength 900℃X3h≥95Mpa, bending strength 110℃X24h≥25Mpa, bending strength 900℃X3h≥32Mpa, thermal conductivity (1000 degrees Celsius)≥7 W / M.k

[0030] The construction performance is excellent, and it is basically solidified in 48 hours.

[0031] Example 3

[0032] The erosion-resistant ramming material for aluminum electrolytic cell is composed of 90% silicon carbide, 1% alumina hollow sphere, 2% α-Al2O3 powder, 3% silicon powder, 0.1% dispersing agent, and 3.9% 75 cement.

[0033] Silicon carbide, 3-1 mm section 22%; 1-0.5 mm section 17%; 0.5-0 mm section 28%; 180 mesh fine powder 33%.

[0034] The sum of the weight percentage of the particle size distribution of the alumina hollow spheres 1-0.2mm is 1%.

[0035] The actual detection results of the ratio are as follows: SiC≥88%, bulk density≥2.65g / cm 3 , porosity≤16.2%, pressure resistance 110℃X24h≥50Mpa, pressure resistance 900℃X3h≥95Mpa, bending resistance 110℃X24h≥20Mpa, bending resistance 900℃X3h≥25Mpa, thermal conductivity (1000℃) ≥7W / M.k

[0036] The construction performance is good, and the basic solidification is achieved in 30 hours.

[0037] Example 4

[0038] The erosion-resistant ramming material for aluminum electrolytic cell is composed of 87% of silicon carbide, 1% of alumina hollow spheres, 1% of α-Al2O3 powder, 5% of silicon powder, 0.7% of dispersing agent and 5.3% of 75 cement.

[0039] The silicon carbide is selected as 17% of 3-1mm section, 23% of 1-0.5mm section, 29% of 0.5-0mm section and 31% of 180 mesh fine powder.

[0040] The sum of the weight percentage of the particle size distribution of the alumina hollow spheres 2-1mm is 1%.

[0041] The actual detection results of the ratio are as follows: SiC≥85%, bulk density≥2.58g / cm 3 , porosity≤17%, pressure resistance 110℃X24h≥50Mpa, pressure resistance 900℃X3h≥100Mpa, bending resistance 110℃X24h≥25Mpa, bending resistance 900℃X3h≥30Mpa, thermal conductivity (1000℃) ≥7W / M.k

[0042] The construction performance is good, and the basic solidification is achieved in 20 hours.

[0043] The product has been used in all aluminum plants in the country for more than ten years of research and practical application, including Inner Mongolia Datang, Sichuan Kia, Shandong Chiping Xinsource, Xinjiang Tianlong, Xinjiang No.6 Agricultural Division, Gansu Dongxing Aluminum and the like, and the effect is good.

Claims

1. Anti-corrosion ramming mix for aluminum electrolytic cells, characterized in that: It is composed of main raw materials, auxiliary raw materials, α-Al2O3 powder, curing powder, dispersant, and curing agent. The weight percentage of each raw material is as follows: main raw material 86-90%, auxiliary raw materials 1-6%, α-Al2O3 powder 1-6%, curing powder 1-6%, and curing agent 1-6%. The total weight percentage of the main raw material, auxiliary raw materials, α-Al2O3 powder, curing powder, and curing agent is 100%. The weight percentage of the dispersant in the main raw material, auxiliary raw material, α-Al2O3 powder, curing powder, and curing agent is 0.1-1%. The main raw material is silicon carbide, with 10-25% selected for the 3-1mm segment and 20-35% for the 1-0.5mm segment. 0.5-0mm section 15-30%; 180 mesh fine powder 20-35%; auxiliary raw materials are 2-1mm hollow alumina spheres and 180 mesh alumina fine powder, with a total weight percentage of 1-6%; the main raw material silicon carbide reacts with cryolite molten salt to generate high-viscosity NaAlSiO4, which can prevent the aluminum liquid from corroding the lining.

2. The anti-corrosion ramming material for aluminum electrolytic cells according to claim 1, characterized in that: Hollow alumina spheres with a purity of over 99%.

3. The anti-corrosion ramming material for aluminum electrolytic cells according to claim 1, characterized in that: The cured powder is silicon micropowder.

4. The anti-corrosion ramming material for aluminum electrolytic cells according to claim 1, characterized in that: The curing agent is 75 calcium aluminate cement.

5. The anti-corrosion ramming material for aluminum electrolytic cells according to claim 1, characterized in that: The preparation method is as follows: mix all raw materials, including main raw materials, auxiliary raw materials, α-Al2O3 powder, curing powder, dispersant, and curing agent evenly, and finally seal and store them. When using them on site, take them out as needed, and add binder water as needed. The mass ratio of water to ramming material is 12-15:100.