Back lining dry material for molten aluminum launder and preparation method of back lining dry material

Abstract

The invention provides a backing dry material for a molten aluminum launder and a preparation method of the backing dry material, and relates to the technical field of refractory materials. The backing dry material for the molten aluminum launder comprises the following raw materials: 40%-55% of heavy aggregate, 10%-25% of lightweight aggregate, 20%-35% of fine powder, 1.5%-3.5% of a curing agent, 1.5%-4.0% of a sintering agent, 1.0%-4.0% of a reactive anti-seepage agent, 0.5%-2.5% of a fiber reinforcing agent and 0.5%-1.0% of a wetting agent. The preparation method comprises the following steps: uniformly mixing the fiber reinforcing agent, the heavy aggregate and the wetting agent; adding other components into the lightweight aggregate; the two materials are uniformly mixed. When the working lining is damaged and molten aluminum permeates, the reactive anti-seepage agent can react with the molten aluminum in a high-temperature environment to actively block a path for continuous permeation of the molten aluminum, so that the potential safety hazard of an aluminum leakage accident caused by the fact that the molten aluminum rapidly burns through a shell is avoided, and the safety and reliability of operation of the molten aluminum runner are remarkably improved.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of refractory materials, in particular to a back lining dry material for an aluminum liquid launder and a preparation method thereof. BACKGROUND

[0002] The aluminum liquid launder is a key equipment in the aluminum smelting process, generally adopts a three-layer structure of a working lining, a back lining and an outer shell, wherein the back lining refers to a layer of material filled after the working lining and before the outer shell of the aluminum liquid launder, which does not directly contact the aluminum liquid, but serves as a support and heat preservation layer, and the back lining material bears the important functions of supporting the working lining, heat insulation and buffering thermal stress.

[0003] The back lining material is generally divided into dry ramming material and wet material. The dry ramming material gradually replaces the wet material due to its simple construction and no need for baking. However, the traditional back lining material is a passive structure, once the working lining is damaged, the aluminum liquid will quickly penetrate the back lining and burn through the launder shell, causing disastrous accidents such as "aluminum running". Moreover, the fine powder flies in the mixing and ramming process, seriously polluting the environment and endangering the health of the operators.

[0004] Therefore, it is an urgent need to develop a back lining dry material with low dust and high safety factor in the technical upgrading of the field. SUMMARY

[0005] In order to improve the safety hazards and large construction dust of the back lining of the aluminum liquid launder in the prior art, the application provides a back lining dry material for an aluminum liquid launder and a preparation method thereof.

[0006] In the first aspect, the application provides a back lining dry material for an aluminum liquid launder, which adopts the following technical scheme: A back lining dry material for an aluminum liquid launder, comprising the following raw materials by weight percentage: heavy aggregate 40-55%, light aggregate 10-25%, fine powder 20-35%, solidifying agent 1.5-3.5%, sintering agent 1.5-4.0%, reactive anti-seepage agent 1.0-4.0%, fiber reinforcing agent 0.5-2.5%, and wetting agent 0.5-1.0%.

[0007] The application uses heavy aggregate, light aggregate and fine powder to cooperate with each other to form the main material of the entire back lining dry material. While ensuring the support strength by using heavy aggregate, the heat insulation effect is improved by using light aggregate with low thermal conductivity. In addition, the fine powder can cooperate with the sintering agent to fill the voids and promote high-temperature sintering, thereby improving the material density and enhancing the ability to buffer thermal stress.

[0008] The application adds a reactive anti-infiltration agent in the backing dry material for the aluminum liquid runner, when the aluminum liquid penetrates the working lining accidentally, the reactive anti-infiltration agent added in the backing will have a violent aluminothermic reaction with the aluminum liquid, and instantaneously generate high-melting-point solid products such as Al2O3 and Fe. These products quickly block the penetration channel like a "plug", forming a hard barrier layer, thereby converting the continuous "aluminum running" accident into a local, controllable small-range solidification.

[0009] The application can pre-wet and wrap the aggregate and fine powder by adding a wetting agent in the backing dry material for the aluminum liquid runner, significantly reducing the flying of fine powder during the subsequent mixing and on-site tamping construction process, and effectively improving the working environment. Compared with the dry material without adding a wetting agent, the dust generation is greatly reduced.

[0010] Optionally, the sintering agent includes one or both of boric acid and glass powder.

[0011] Optionally, the sintering agent is composed of boric acid and glass powder, and the weight ratio of the boric acid to the glass powder is (1-2):1.

[0012] Optionally, the glass powder is a low-melting-point sodium-calcium-silicon glass powder, and the softening point temperature is 600-800℃.

[0013] For a traditional aluminum liquid runner, the backing layer generally relies on an organic binder to provide room temperature strength, but at medium and high temperature stages (500-1000℃), due to the loss of organic binder, the ceramic structure has not been fully formed, and a "strength trough" easily occurs, resulting in loose collapse of the backing layer, which cannot provide sufficient support for the runner prefabricated part, and thus has the defect of insufficient strength at medium and high temperature stages.

[0014] Therefore, the application uses a sintering agent composed of boric acid and glass powder, in which the boric acid melts at a relatively low temperature (~500℃) as an active agent to fill the gap between particles and promote preliminary sintering, and the glass powder melts at a higher temperature (600-800℃) to form a gradient sintering effect with the boric acid, further densifying the material structure, thereby building a strong ceramic bonding network. By compounding boric acid and glass powder, the actual working temperature of the aluminum liquid runner can be matched, ensuring effective sintering at different temperature intervals and improving the overall strength and anti-infiltration performance of the backing dry material.

[0015] Optionally, the reactive anti-infiltration agent includes a mixture of one or both of iron oxide and cryolite.

[0016] Iron oxide (Fe2O3) can react with molten aluminum at high temperature by aluminothermy, generating high melting point Al2O3 and metallic iron. The product can block the internal pores of the material and form a physical-chemical composite anti-infiltration barrier. Cryolite (Na3AlF6) as a fluoride can react with molten aluminum at high temperature to generate low viscosity molten salt, but because of its high melting point and the reaction product can fill the pores, it can effectively prevent the infiltration of molten aluminum. Therefore, both iron oxide and cryolite have good reactivity with molten aluminum, and the reaction product has high stability, which can prevent further penetration of the molten aluminum to the outer shell after the molten aluminum penetrates the working lining.

[0017] Optionally, the reactive anti-infiltration agent further comprises copper oxide, and the amount of the copper oxide added is 10% to 20% of the mass of the reactive anti-infiltration agent.

[0018] The application can add copper oxide to the reactive anti-infiltration agent, which can be used as a high-temperature color change indicator in aluminothermy. In aluminothermy, copper oxide is also reduced by aluminum (3CuO + 2Al → 3Cu + Al2O3), which changes color from black to purple red. This color change in the local area serves as a warning, gaining valuable time for emergency measures.

[0019] Optionally, the wetting agent is a suspension of nano-oxide and an organic solvent, and the nano-oxide is nano-silicon dioxide or nano-aluminum oxide with a particle size range of 10-100 nm.

[0020] Optionally, the mass percentage of the nano-oxide in the wetting agent is 10% to 15%.

[0021] Optionally, the organic carrier is a high-boiling organic carrier, and further preferably is polyethylene glycol with a molecular weight range of 200-600.

[0022] Optionally, the preparation method of the wetting agent is as follows: The nano-oxide powder is uniformly dispersed in polyethylene glycol, and a stable suspension system is formed by high-speed shearing emulsifier treatment at a speed of 15000 rpm for 10 minutes with a material temperature of 40°C.

[0023] Nano-oxide has extremely high specific surface area and surface activity, and can tightly wrap fine powder particles through physical adsorption or chemical action, significantly reducing the flying property of fine powder; the organic solvent as a carrier can uniformly disperse the nano-oxide, ensuring its full contact with the fine powder, and further enhancing the dust suppression effect.

[0024] Moreover, the nano-oxide particles provide a large specific surface area and reactivity, effectively reducing the sintering activation energy, promoting solid-phase reaction and sintering densification at low temperatures, and continuously increasing the strength of the material in the range of 500-800℃, solving the problem of strength reduction in this temperature range and providing sufficient support for the flow channel prefabricated part.

[0025] Optionally, the wetting agent is industrial white oil.

[0026] Industrial white oil is inexpensive and can wrap fine powder particles through physical lubrication, reducing dust flying during mixing and ramming, reducing material cost while ensuring low dust effect. Moreover, industrial white oil has stable chemical properties and good compatibility with other raw materials, and its low viscosity characteristics can improve the flowability of the material, facilitate ramming during construction, and ensure that the dry backing material is tightly attached to the flow channel structure.

[0027] Optionally, the heavy aggregate includes one or more of flint stone aggregate, andalusite aggregate, and mullite aggregate.

[0028] Flint stone, andalusite, and mullite are all high-alumina refractory materials with high melting point, high strength, and excellent thermal stability, which can be used as the backbone of the dry backing material to ensure that it does not soften or collapse during long-term high-temperature service in the aluminum flow channel, meeting the core requirement of supporting the working lining.

[0029] Optionally, the particle size of the heavy aggregate is not more than 5mm.

[0030] Optionally, the light aggregate includes a mixture of one or more of perlite, floating beads, and lightweight ceramic particles.

[0031] Further, the particle size of the light aggregate is 1-3mm, and the packing density is 0.1-0.2g / cm 3 .

[0032] Perlite, floating beads, and lightweight ceramic particles are all low thermal conductivity materials that can significantly reduce the overall thermal conductivity of the dry backing material, enhance the thermal insulation effect, reduce the heat loss of the aluminum liquid, and reduce the thermal load of the flow channel shell. Moreover, lightweight aggregate has low density, which can reduce the overall weight of the backing material and reduce the bearing pressure of the flow channel steel shell; its porous structure can also absorb thermal stress, improve the cushioning performance of the material, and avoid structural damage caused by thermal shock.

[0033] Optionally, the fine powder includes a mixture of one or more of andalusite fine powder, kyanite fine powder, and quartz sand fine powder.

[0034] Optionally, the particle size of the fine powder is 200-325 mesh.

[0035] The andalusite fine powder and the kyanite fine powder can expand at high temperature, which can compensate for the sintering shrinkage of the material, avoid cracks caused by volume shrinkage, and improve the structural integrity; the quartz sand fine powder has good filling property, which can fill the small gaps between the aggregates, and cooperates with the phase change expansion fine powder to further improve the material density, and enhance the impermeability and thermal insulation performance.

[0036] The existing backing material is prone to cracks under the temperature change caused by starting and stopping the furnace, which affects its long-term supporting effect, and thus the thermal shock resistance and structural stability of the backing are insufficient.

[0037] Therefore, the present application can effectively improve the thermal shock resistance and structural stability of the backing by using the compounding of fine powder, lightweight aggregate and fiber reinforcing agent. The fine powder can be converted into mullite at high temperature, and the volume expansion brought by it effectively compensates for the sintering shrinkage of the material, so that the backing layer is more dense. The introduction of lightweight aggregate and fiber reinforcing agent improves the rapid cooling and heating resistance of the material and reduces the risk of crack generation.

[0038] Optionally, the curing agent is a thermosetting phenolic resin powder.

[0039] Optionally, the fiber reinforcing agent is an organic fiber, and is further preferably cellulose fiber or polypropylene fiber.

[0040] In a second aspect, the present application provides a preparation method of a backing dry material for an aluminum liquid channel, which adopts the following technical scheme: A preparation method of a backing dry material for an aluminum liquid channel, comprising the following steps: Step S1: The fiber reinforcing agent is added to the heavy aggregate for pre-mixing, and then the wetting agent is added for continuous stirring to obtain a mixture A; Step S2: The fine powder, the curing agent, the sintering agent and the reactive impermeability agent are sequentially added to the lightweight aggregate, and stirring is performed to obtain a mixture B; Step S3: The mixture A is added to the mixture B for continuous stirring until all components are uniformly mixed, the material is discharged and immediately sealed and packaged with moisture-proof packaging material to obtain the backing dry material for the aluminum liquid channel.

[0041] In the preparation of the dry backing material, the fiber reinforcing agent is pre-mixed with the heavy aggregate, which can avoid the fiber from clumping in the subsequent mixing process, ensure its uniform dispersion in the material, and fully play the role of enhancing toughness. The wetting agent is added in the pre-mixing stage, which can wrap the surface of the heavy aggregate and the fiber reinforcing agent in advance, reduce the flying of fine powder in the subsequent mixing process. Moreover, the light aggregate is mixed with the functional components such as fine powder and curing agent in steps, which can avoid the fine powder from being wrapped by the heavy aggregate and ensure the stability of the functions such as curing, sintering and anti-permeation. The step-by-step mixing also reduces the dust release amount in a single mixing process, further improving the working environment.

[0042] In summary, the present application includes at least one of the following beneficial effects: 1. By introducing a reactive anti-permeation agent, when the working lining is damaged and the molten aluminum penetrates, the reactive anti-permeation agent can react with the molten aluminum at high temperature, actively blocking the path of the molten aluminum penetration, avoiding the safety hazard of rapid burning of the molten aluminum through the shell and causing aluminum running accidents, and significantly improving the safety and reliability of the molten aluminum channel operation.

[0043] 2. By adding a wetting agent, the fine powder particles can be effectively wrapped, the surface tension can be reduced, the flying of fine powder during mixing and tamping can be reduced, and the working environment can be greatly improved. BRIEF DESCRIPTION OF DRAWINGS

[0044] Fig. 1 is the penetration surface picture of the sample of example 1 in the molten aluminum erosion penetration test; Fig. 2 is the penetration surface picture of the sample of example 3 in the molten aluminum erosion penetration test; Fig. 3 is the penetration surface picture of the sample of comparative example 1 in the molten aluminum erosion penetration test. DETAILED DESCRIPTION

[0045] The technical solutions of the present application will be described in detail below with specific examples. Obviously, the described examples are only a part of the examples of the present application, not all examples. The following description of at least one exemplary embodiment is actually only illustrative, but not as any limitation on the present application and its application or use. Based on the examples in the present application, all other examples obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0046] The industrial white oil used in the examples and comparative examples of the present application is industrial white oil (II) No. 100 produced by Changzhou Zhongke Synthetic Materials Co., Ltd.

[0047] The glass powder used in the examples and comparative examples of the present application is a low-melting-point sodium-calcium-silicon glass powder, and its softening point temperature is 600-800℃.

[0048] Preparation Example 1 Preparation Example 1 provides a wetting agent, and the specific preparation process is as follows: uniformly disperse nano-silicon dioxide powder (particle size 20-30 nm) in polyethylene glycol (PEG-200) at a mass ratio of 1:9, and form a stable suspension system by high-speed shearing emulsifier, stirring speed 15000 rpm, stirring time 10 minutes, material temperature 40℃.

[0049] Preparation Example 2 Preparation Example 2 provides a wetting agent, and the specific preparation process is as follows: uniformly disperse nano-aluminum oxide powder (particle size 20-80 nm) in polyethylene glycol (PEG-200) at a mass ratio of 1:9, and form a stable suspension system by high-speed shearing emulsifier, stirring speed 15000 rpm, stirring time 10 minutes, material temperature 40℃.

[0050] Example 1 Example 1 provides a backing dry material for aluminum liquid channel, and the mass ratio of each component is as follows: heavy aggregate 45%, light aggregate 25%, fine powder 20%, curing agent 3.5%, sintering agent 2.5%, reactive impermeable agent 1%, fiber reinforcing agent 2.5%, and wetting agent 0.5%. Among them, the heavy aggregate is coke stone aggregate, the light aggregate is perlite, the fine powder is kyanite fine powder, the curing agent is phenolic resin, the sintering agent is composed of boric acid and glass powder at a mass ratio of 3:2, the reactive impermeable agent is iron oxide, the fiber reinforcing agent is cellulose fiber, and the wetting agent is industrial white oil.

[0051] The preparation method of the above-mentioned backing dry material for aluminum liquid channel specifically includes the following steps: S1, the fiber reinforcing agent and the heavy aggregate are artificially pre-mixed to disperse, and then the two are put into a stirrer, and the wetting agent is slowly added under stirring conditions, and stirred for 4 minutes; S2, add fine powder, curing agent, sintering agent and reactive impermeable agent to the light aggregate, and stir for 5 minutes; S3, add the material obtained in step S1 to the material mixed in step S2, continue to stir for 5 minutes after mixing, and discharge, and seal and package with kraft paper bag.

[0052] Example 2 Example 2 provides a backing dry material for aluminum liquid channel, and the mass ratio of each component is as follows: heavy aggregate 55%, light aggregate 10%, fine powder 25%, curing agent 3%, sintering agent 1.5%, reactive impermeable agent 4%, fiber reinforcing agent 1%, and wetting agent 0.5%. The heavy aggregate is andalusite aggregate, the light aggregate is light ceramic granule, the fine powder is andalusite fine powder, the curing agent is phenolic resin, the sintering agent is boracic acid and glass powder which are mixed according to the mass ratio of 2:1, the reactive anti-seepage agent is iron oxide, the fiber reinforcing agent is polypropylene fiber, and the wetting agent is industrial white oil.

[0053] The preparation method of Example 2 is basically the same as that of Example 1, and details are not repeated here.

[0054] Example 3 Example 3 provides a dry backing material for molten aluminum flow tank, and the mass ratio of each component is as follows: heavy aggregate 40%, light aggregate 15%, fine powder 35%, curing agent 1.5%, sintering agent 4%, reactive anti-seepage agent 3%, fiber reinforcing agent 0.5%, and wetting agent 1%. The heavy aggregate is mullite aggregate, the light aggregate is floating bead, the fine powder is quartz sand fine powder, the curing agent is phenolic resin, the sintering agent is boracic acid and glass powder which are mixed according to the mass ratio of 1:1, the reactive anti-seepage agent is iron oxide, ice crystal and copper oxide which are mixed according to the mass ratio of 2:2:1, the fiber reinforcing agent is cellulose fiber, and the wetting agent is industrial white oil.

[0055] The preparation method of Example 3 is basically the same as that of Example 1, and details are not repeated here.

[0056] Example 4 Example 4 is basically the same as Example 1, and the only difference is that the wetting agent in Example 4 is the wetting agent prepared in Preparation Example 1.

[0057] Example 5 Example 5 is basically the same as Example 1, and the only difference is that the wetting agent in Example 5 is the wetting agent prepared in Preparation Example 2.

[0058] Example 6 Example 6 is basically the same as Example 1, and the only difference is that the sintering agent in Example 6 is boracic acid.

[0059] Example 7 Example 7 is basically the same as Example 1, and the only difference is that the sintering agent in Example 6 is glass powder.

[0060] Comparative Example 1 Comparative Example 1 is basically the same as Example 1, and the only difference is that the reactive anti-seepage agent in Comparative Example 1 is replaced by equal mass of perlite.

[0061] Comparative Example 2 Comparative Example 2 is basically the same as Example 1, and the only difference is that the sintering agent in Comparative Example 2 is replaced by equal mass of perlite.

[0062] Performance detection test item one-ambient temperature pressure resistance test: The backing dry mix prepared in the above examples and comparative examples was made into samples for testing its performance. The sample preparation used a 160 mm x 40 mm x 40 mm metal triplex test mold as a mold, and during sample preparation, the backing dry mix was loaded into the test mold, vibrated, tamped, and the surface was smoothed, then the test mold was placed in a forced air drying oven at 180°C x 24h for curing, and the triplex test mold was taken out and the cured sample block was removed, and two samples were prepared for each example or comparative example.

[0063] One sample strip was taken from each of the samples corresponding to each example and comparative example, and the test was carried out according to the test procedure in section 8.2 of GB / T 5072-2023 “Test method for cold crushing strength of refractory materials”, the pressure surface of the sample was aligned with the center of the lower platen of the testing machine, and the load was applied to the sample at a loading rate of 0.2±0.02 MPa / s, until the sample was crushed or compressed to 90% of the original height, the maximum load during the test was recorded, and the cold crushing strength was calculated according to the maximum test load, which was recorded as the cold crushing strength after 180°C curing, and the specific results are shown in Table 1.

[0064] Another sample strip was taken from each of the samples corresponding to each example and comparative example, and placed in a muffle furnace at 600°C x 3h for firing, and then cooled to room temperature. The cold crushing strength of the sample after 600°C firing was tested again according to the test procedure of Test Item 1, and was recorded as the cold crushing strength after 600°C firing.

[0065] Test Item Two - Aluminum Liquid Penetration Test: The backing dry mix of Example 1, Example 3 and Comparative Example 1 was tested according to GB / T 39146-2020 “Test method for resistance of refractory materials to molten aluminum alloy corrosion”, and the sample was prepared and tested. The type of aluminum alloy used in the test was ADC12, and the temperature of the aluminum liquid was 750°C, and the sample was immersed in the aluminum liquid for 0.5h. After the test was completed, the sample was taken out and cooled, and each sample was cut along the central axis, the penetration surface was observed, and the maximum penetration depth of the aluminum liquid on each sample was measured, and the specific results are shown in Table 1.

[0066] Evaluation Item - Construction Dust Rating: The amount of dust generated during the vibration and tamping of the backing dry mix during the sample preparation of Test Item 1 was evaluated, and the evaluation results are shown in Table 1.

[0067] Table 1 Test Results As can be seen from the test results in Table 1, Comparative Example 2, due to the lack of a sintering agent, exhibited a decrease in compressive strength after firing at 600℃ compared to its compressive strength after curing at 180℃. This decrease in strength may be due to the loss of organic binder within this temperature range. In contrast, Example 6 used boric acid as a sintering agent, and Example 7 used glass powder as a sintering agent. Examples 6 and 7 showed improved compressive strength after firing at 600℃ compared to their compressive strength after curing at 180℃, indicating that the addition of the sintering agent can compensate for the strength decrease caused by the loss of organic binder.

[0068] Example 1 uses a sintering agent composed of boric acid and glass powder, which constructs a continuous ceramic sintering network in the dry lining. This significantly increases the compressive strength after firing at 600℃, a 46% increase compared to the compressive strength after curing at 180℃. Even though the organic binder will burn off at this temperature, reducing its bonding function and thus strength, the ceramic sintering network constructed by the sintering agent compensates for this strength reduction and even exceeds the original strength, effectively supporting the working lining. Therefore, compared to using boric acid and glass powder alone, using a compound of boric acid and glass powder can greatly improve the compressive strength of the dry lining in the high-temperature range of 500–1000℃.

[0069] In the aluminum molten metal erosion penetration test, the maximum penetration depth of Examples 1 and 3 was only 3 mm, while the maximum penetration depth of Comparative Example 1 reached 8 mm. This indicates that the reactive penetrant added to the dry material can effectively block the path of aluminum molten metal diffusion to the outer shell, blocking pores and forming a seepage barrier. Moreover, from Figs. 1-3 The comparison also shows that in Examples 1 and 3, the molten aluminum only penetrated a small amount around the sample boundary before ceasing further penetration, indicating that the penetration path was effectively blocked. In contrast, in Comparative Example 1, the molten aluminum penetrated a wider range and deeper around the sample boundary. Therefore, the reactive penetrant added to the dry material in this application can block the penetration path of the molten aluminum.

[0070] Moreover, the results of the construction dust evaluation show that both adding industrial white oil and nano-oxide suspension can effectively suppress the flying of dust particles, and the dust suppression effect of nano-oxide type is better.

[0071] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A dry backing for a molten aluminum launder characterized in that, The raw materials include the following weight percentages: heavy aggregate 40-55%, light aggregate 10-25%, fine powder 20-35%, curing agent 1.5-3.5%, sintering agent 1.5-4.0%, reactive anti-permeation agent 1.0-4.0%, fiber reinforcing agent 0.5-2.5%, and wetting agent 0.5-1.0%.

2. The dry backing for a molten aluminum launder according to claim 1, wherein The sintering agent includes one or both of boric acid and glass powder.

3. The dry backing for a molten aluminum launder of claim 2, wherein, The sintering agent consists of boric acid and glass powder, wherein the weight ratio of the boric acid to the glass powder is (1-2):

1.

4. The dry backing for a molten aluminum launder of claim 1 wherein, The reactive anti-permeation agent includes one or both of iron oxide and cryolite.

5. The dry backing for a molten aluminum launder of claim 4, wherein, The reactive anti-permeation agent further includes copper oxide, and the amount of the copper oxide added is 10-20% of the mass of the reactive permeation agent.

6. The dry backing for a molten aluminum launder of claim 1 wherein, The wetting agent is a suspension of nano-oxide and organic solvent, wherein the nano-oxide is nano-silicon dioxide or nano-aluminum oxide with a particle size range of 10-100 nm.

7. The dry backing for a molten aluminum launder of claim 1 wherein, The wetting agent is industrial white oil.

8. The dry backing for a molten aluminum launder of claim 1 wherein, The heavy aggregate includes one or more of flint stone aggregate, andalusite aggregate, and mullite aggregate. The light aggregate includes one or more of perlite, floating bead, and light ceramic aggregate.

9. The dry backing for a molten aluminum launder of claim 1 wherein, The fine powder includes one or more of andalusite fine powder, kyanite fine powder, and quartz sand fine powder.

10. A method of producing a backing dry powder for a molten aluminum launder according to any one of claims 1-9, characterized in that, The method includes the following steps: Step S1: the fiber reinforcing agent is added to the heavy aggregate for premixing, and then the wetting agent is added for further stirring to obtain a mixture A; Step S2: the fine powder, the curing agent, the sintering agent, and the reactive anti-permeation agent are sequentially added to the light aggregate for stirring to obtain a mixture B; Step S3: the mixture A is added to the mixture B for further stirring until all components are uniformly mixed, the material is discharged and immediately sealed with moisture-proof packaging material to obtain the backing dry material for the aluminum liquid channel.

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