Component system

Abstract

The invention relates to a component system for use as a water-miscible dry mixture for producing a thermal protective layer (34) in a metallurgical furnace (2), the wall (12) of which separates a chamber (10) from an outer space (14), wherein the thermal protective layer (34) is designed such that it allows for a controlled temperature drop between a chemically protective layer (38) facing the chamber (10) and a mechanically stabilizing outer shell (30), comprising: - a refractory aggregate containing a thermal insulation material selected from a group consisting of aluminum oxide, aluminosilicates, silicon dioxide, magnesia, zirconia or combinations thereof, - a binder containing cement for chemical curing by reaction with water, and - a foaming agent containing a chemically amphiphilic material, wherein, when mixing the dry mixture with water, a hydrophilic part of the amphiphilic material remains in the water, while a hydrophobic part is oriented towards the air or other hydrophobic substances in order to reduce a surface tension of the water and to stabilize air bubbles.

Description

[0001] VON BÜLOW & TAMADA

[0002] ROTBUCHENSTR. 6 Patent Attorney D-81547 MUNICH DR. TAM AXEL VON BÜLOW TEL: +49-(0)89-642 3094 LAW FIRM FOR INNOVATION PROTECTION (retired) FAX: +49-(0)89-64 63 42

[0003] Patent Attorney EMAIL: office@vb-t.com SASCHA TAMADA Attorney at Law ALEXANDER GINZBURG

[0004] Patent attorney LIANJI JIN

[0005] January 26, 2026

[0006] Applicant: EKW GmbH

[0007] Applicant number: BP-X0-E122-033-XP-1

[0008] Kom po ne nte n sy ste m

[0009] Description

[0010] The present invention relates to a component system for use as a water-miscible dry mixture for the production of a thermal insulation material in a metallurgical furnace, a method for producing a wall in the furnace of the metallurgical furnace and the metallurgical furnace.

[0011] From EP 0 015 135 Al, refractory bricks are known which are produced from a component system with a refractory aggregate and a hardening binder. To create the pore structure, a pore-forming agent is added to the mixture, which is burned during a firing process to produce a porous structure in the brick.

[0012] The purpose of the invention is to improve the known component system.

[0013] According to one aspect of the invention, a component system for use as a water-miscible dry mix for the production of a thermal protective layer in a metallurgical furnace, the wall of which separates a chamber from an outer space, comprises B-P-X0-E122-033-XP-1 New application EKW GmbH January 26, 2026

[0014] The thermal protection layer is designed to allow a controlled temperature drop between a chemically protective layer facing the chamber and a mechanically stabilizing outer shell. The following ingredients are used:

[0015] - a refractory aggregate containing a thermal insulation material selected from a group consisting of aluminium oxide, aluminosilicates, silicon dioxide, magnesia, zirconia or combinations thereof,

[0016] - a binder containing cement for chemical hardening by reaction with water, and

[0017] - a foaming agent containing a chemically amphiphilic material, wherein when the dry mixture is mixed with water a hydrophilic part of the amphiphilic material remains in the water, while a hydrophobic part orients itself towards the air or other hydrophobic substances to reduce the surface tension of the water and stabilize air bubbles.

[0018] Based on the aforementioned component system, the proposed component system is based on the premise that the use of an amphiphilic foaming agent can create a uniform and stable pore structure in the thermal protection layer. The amphiphilic foaming agent is characterized by possessing both hydrophilic and hydrophobic properties. This allows for the creation of stable air bubbles in the mixture during mixing with water, as the hydrophilic part of the foaming agent interacts with the water phase, while the hydrophobic part stabilizes the interface with the air. This property effectively reduces the surface tension of the water, enabling long-term stabilization of the bubbles without the need for additional energy or processing steps.

[0019] The use of the amphiphilic foaming agent in the specified component system therefore means that the thermal protection layer can only be produced by air drying. In contrast to conventional methods, where B-P-X0-E122-033-XP-1 New registration EKW GmbH January 26, 2026

[0020] While pore-forming agents such as wood chips or polystyrene must be removed by thermal burning, the pore structure is preserved in this case through the physicochemical stabilization of the foaming agent. This eliminates the complex burning process for removing organic pore-forming agents, making production more efficient, cost-effective, and environmentally friendly.

[0021] In this way, the specified component system can be used to produce a wall for a metallurgical furnace that not only offers excellent thermal insulation performance but also exhibits a uniform pore structure characterized by low density, high stability, and low thermal conductivity. Furthermore, eliminating the need for a thermal burnout process allows for faster and more resource-efficient manufacturing. Since no volatile components such as organic pore-forming agents need to be burned off, the chemical composition of the final product remains stable, improving its long-term stability in high-temperature, chemically demanding environments.

[0022] Furthermore, the specified component system offers a multitude of additional advantages. One of these advantages lies in the energy savings achieved by eliminating the need for a thermal firing process. Since the material cures entirely through air drying, a significant portion of the energy typically required for burning out organic pore-forming agents is eliminated. This not only leads to a substantial reduction in production costs but also makes the process considerably more sustainable and environmentally friendly.

[0023] Another advantage is the reduction of harmful emissions, as no organic substances such as wood shavings or polystyrene need to be burned during production. This means that neither smoke nor carbon dioxide or other pollutants are released, making the process particularly environmentally friendly and minimizing the ecological footprint of production. BP-X0-E122-033-XP-1 New registration EKW GmbH January 26, 2026

[0024] The specified component system is also characterized by its high degree of flexibility in application. The water-miscible dry mix can be processed directly on-site and poured into molds or applied to walls, allowing for easy adaptation to different geometries and requirements. This makes the process versatile and facilitates installation in various furnace types and applications.

[0025] Another significant advantage is the improved process control made possible by the properties of the amphiphilic foaming agent. The foaming agent's physicochemical properties allow for precise control of pore size and distribution within the material. This results in a uniform pore structure that optimizes insulation performance and mechanical stability. The outcome is a final product with consistent properties that meets the demanding requirements of metallurgical furnaces.

[0026] Furthermore, the specified component system enables significant time savings, as air drying is considerably faster than a complete firing process. This not only reduces production time but also increases manufacturing efficiency.

[0027] In a further development of the specified component system, the amphiphilic material of the foaming agent is an organic material. This enables particularly efficient and uniform pore formation, as organic amphiphilic substances, such as protein-containing compounds or synthetic surfactants, are highly effective at reducing the surface tension of water. This property allows for optimal stabilization of the air bubbles during processing and leads to a homogeneous pore structure in the final material. A further advantage arises from the versatility of organic materials, as they can be chemically and physically modified to meet specific requirements for pore size and stability. For example, natural proteins such as B-P-X0-E122-033-XP-1 (New registration EKW GmbH, January 26, 2026) can be used.

[0028] Hydrolyzed keratin or casein can be biodegradable, making the material more environmentally friendly and simultaneously increasing the sustainability of the production process. Furthermore, organic amphiphilic materials exhibit low residue formation. They can be completely decomposed during air drying or any subsequent heat treatment without leaving significant chemical residues, thus improving the purity and quality of the final product. This is particularly advantageous for applications in metallurgical furnaces, where chemical stability and purity of the material are crucial. The use of an organic foaming agent also improves the processability of the dry mix, as organic substances often have an additional plasticizing effect.This facilitates mixing, application, and shaping of the material, increasing manufacturing flexibility and improving efficiency on the construction site or in the production process. Additionally, an organic amphiphilic material often allows for a more energy-efficient manufacturing process, as its production requires fewer complex chemical or physical processing steps. Combined with the improved insulation and strength properties of the final material, the use of an organic foaming agent represents a sustainable, flexible, and highly effective advancement of the specified component system.

[0029] In a further development of the specified component system, the organic material of the foaming agent is protein-based, synthetic, or polymer-based. If the foaming agent is protein-based, advantages arise particularly in terms of environmental friendliness and biodegradability. Protein-containing materials such as hydrolyzed keratin or casein are of natural origin and can be completely decomposed during the drying process or any subsequent heat treatment without leaving harmful residues. Furthermore, protein-based foaming agents produce a particularly elastic and stable foam. (B-P-X0-E122-033-XP-1 New registration EKW GmbH January 26, 2026)

[0030] The foaming effect is due to the molecular structure of proteins, which are capable of forming robust films at the water-air interface. This ensures uniform pore formation and long-lasting insulation performance of the material. If the foaming agent is synthetic, such as one based on alkyl sulfates, alkyl ethers, or betaine compounds, it achieves particularly high effectiveness in reducing the surface tension of water. This leads to rapid and efficient foam formation, which facilitates processing of the material. Synthetic foaming agents also allow for precise control of pore size and distribution, resulting in a final product with consistent properties. These materials are characterized by their cost-effective production and long shelf life, making them an economically attractive option.If the foaming agent is polymer-based, for example through the use of polyvinyl alcohol (PVA) or styrene-maleic acid polymers, advantages arise in the stability and viscosity of the mixture. Polymer-based foaming agents produce tough and durable foams that are particularly resistant to physical stresses during mixing or application. Furthermore, polymers promote the homogeneity of the material by uniformly stabilizing the air bubbles in the mixture. This results in a fine and stable pore structure that offers excellent thermal insulation and mechanical strength.

[0031] In another further development of the specified component system, the thermal insulation material comprises an adhesive sand containing between 60 wt% and 80 wt% quartz sand and between 10 wt% and

[0032] Contains 30 wt% of an aluminosilicate, preferably kaolin. This composition offers several advantages, particularly with regard to the mechanical stability, thermal resistance, and processability of the material. The high proportion of quartz sand ensures a robust base structure for the thermal protection layer, as quartz sand exhibits high compressive strength and its thermal properties remain stable even at high temperatures. This makes the material particularly suitable for the extreme conditions in metallurgical environments. B-P-X0-E122-033-XP-1 New registration EKW GmbH January 26, 2026

[0033] Furnaces. The inclusion of at least 10 wt% of an aluminosilicate, such as kaolin, offers further advantages. Kaolin consists of aluminum oxide (Al₂O₃) and silicon dioxide (SiO₂) in a ratio that is optimal for the formation of mullite at high temperatures. Mullite is characterized by excellent thermal insulation properties, chemical stability, and mechanical strength. This enables the material to withstand the high thermal stresses in the wall of a metallurgical furnace while simultaneously ensuring a controlled temperature drop between the chemical protection layer and the mechanical stabilization shell. Furthermore, the adhesive sand improves the material's workability. The fine-grained structure of quartz sand and kaolin makes the material easy to mix and shape, facilitating on-site handling.The adhesive sand also acts as a binder, strengthening the adhesion between the particles and further increasing the mechanical stability of the wall. This is particularly important to ensure the long-term durability and resilience of the thermal protection layer.

[0034] According to a further aspect of the invention, a method for producing a wall separating a chamber of a metallurgical furnace from an external space with one of the specified component systems comprises the steps of mixing the refractory aggregate with the binder; producing a slurry by adding water to the refractory aggregate mixed with the binder;

[0035] Forming a foam from the foaming agent and water; forming the thermal protective layer by stirring the foam into the slurry; applying the thermal protective layer to the mechanically stabilizing outer shell; applying the chemically protective layer to the thermal protective layer, and drying the thermal protective layer.

[0036] By using the specified component system in the specified method, a particularly uniform pore distribution in the thermal protection layer can be achieved, since the B-P-X0-E122-033-XP-1 new registration EKW GmbH 26 January 2026

[0037] The foam is produced before being mixed with the slurry. This ensures that the foam is introduced into the material matrix in a controlled and homogeneous manner, further improving the insulation performance and mechanical stability of the material. Another advantage arises from the two-stage mixing process: the separate formation of the foam and the slurry allows for more precise control of the foam properties, such as bubble size and stability, before they are incorporated into the material. This minimizes the risk of foam collapse or uneven distribution during processing. Furthermore, the direct application of the thermal protection layer to the mechanically stabilizing outer shell results in improved adhesion between the layers. The still-moist and flexible consistency of the material allows for precise adaptation to complex surface geometries, enabling even irregular structures to be insulated uniformly.Furthermore, the use of a premixed foam reduces material segregation during the application process, especially on vertical or inclined surfaces. This ensures a consistent layer thickness and uniform material properties across the entire wall surface. Subsequent drying of the thermal protection layer results in a finished product that directly develops its full mechanical and thermal properties without any further thermal post-treatment or firing process. This not only saves energy but also shortens the wall's production time and minimizes downtime for the metallurgical furnace.

[0038] In a further development of the described process, a ceramic material, preferably an aluminum silicate phase, particularly preferably mullite, is first produced to apply the chemically protective layer to the thermal protective layer and then applied to the thermal protective layer. This approach offers the advantage that the chemically protective layer has extremely low porosity and high density, which effectively protects the thermal protective layer from the penetration of B-P-X0-E122-033-XP-1 during furnace operation. (New application EKW GmbH, January 26, 2026)

[0039] The ceramic protective layer protects the furnace wall from water or other liquid media. This is particularly important because temperature fluctuations and sudden heating can occur in metallurgical furnaces. Without the ceramic protective layer, water vapor or other gases penetrating the pores of the thermal barrier could cause abrupt expansion during rapid temperature increases, potentially damaging the material or leading to spalling. The applied aluminum silicate phase, especially mullite, is characterized by its excellent chemical and thermal stability and prevents such damage through its barrier effect. Furthermore, the ceramic protective layer improves the long-term durability of the wall by protecting the underlying thermal barrier from chemical attack by aggressive gases or slag that can be generated during the operation of the metallurgical furnace.The mullite layer offers an ideal combination of chemical inertness and high mechanical stability at extreme temperatures.

[0040] Additionally, the targeted application of an aluminum silicate phase such as mullite improves the surface hardness of the chemically protective layer. This increases the wall's resistance to mechanical stresses, such as those caused by thermal stresses or material contact during operation.

[0041] In another further development of the specified process, the thermal protective layer is air-dried.

[0042] In a further development of the described process, the slurry is produced by adding a phosphate and / or cellulose. The addition of a phosphate, for example aluminum phosphate, significantly improves the chemical bonding properties of the slurry and leads to faster hardening and higher green strength. This allows for easier processing and increases the stability of the thermal protection layer even in its incompletely dried state. Furthermore, the phosphate promotes the formation of stable chemical compounds. B-P-X0-E122-033-XP-1 New registration EKW GmbH January 26, 2026

[0043] within the matrix, this improves the material's mechanical strength in the long term and increases its resistance to thermal and mechanical stresses during kiln operation. The addition of cellulose also offers significant advantages. Cellulose acts as a rheology modifier, ensuring that the slurry has improved flowability and viscosity without segregating. This facilitates the uniform application of the material to the mechanically stabilizing outer shell and prevents uneven shrinkage of the slurry during drying or curing. Additionally, cellulose acts as a pore structure stabilizer, promoting bubble formation and distribution during processing.The combination of phosphates and cellulose also provides better protection against cracking during drying, as the cellulose retains water in the slurry and allows for controlled evaporation. At the same time, the phosphate ensures increased temperature resistance and chemical stability, allowing the material to maintain its performance even under extreme operating conditions in a metallurgical furnace.

[0044] According to another aspect of the invention, a metallurgical furnace comprises a wall separating a chamber from an outer space, which is produced by one of the specified methods.

[0045] The chemically protective layer can be used as a hot face layer. This design offers the crucial advantage that no further protective layers are required to shield the thermal protection layer from the ingress of water or other liquids. The chemically protective layer, acting as a hot face layer, functions both as a chemical barrier and as a direct covering of the chamber wall, effectively protecting the underlying thermal protection layer from water vapor and other potentially damaging influences. This design reduces the risk of damage, such as cracking or flaking of the thermal protection layer, due to sudden impacts. (B-P-X0-E122-033-XP-1 New registration EKW GmbH January 26, 2026)

[0046] Temperature fluctuations are minimized. Furthermore, the chemically protective layer, due to its high density and low porosity, prevents liquids or aggressive media from penetrating the material in the first place, significantly increasing the overall service life of the wall and the efficiency of the furnace. The elimination of additional protective layers simplifies the design and simultaneously reduces material and production costs, as no further processing steps are necessary.

[0047] The properties, features, and advantages of this invention described above, as well as the manner in which they are achieved, will become clearer in connection with the following description of the exemplary embodiments, which are explained in more detail in conjunction with the drawings. The drawings show:

[0048] Fig. 1 shows a perspective view of a metallurgical furnace.

[0049] The figures use identical technical elements with the same reference symbols and describe them only once. The figures are purely schematic and, above all, do not represent the actual geometric relationships.

[0050] Reference is made to Fig. 1, which shows a perspective view of a metallurgical furnace in the form of a trough induction furnace 2, also called a trough induction furnace, which is below considered in a space spanned by a longitudinal direction 4, a transverse direction 6 transverse to the longitudinal direction 4 and a vertical direction 8 transverse to the longitudinal direction 4 and transverse to the transverse direction 8.

[0051] The trough induction furnace 2 has a chamber 10 open upwards in the vertical direction 8, which is separated from an outer space 14 by a wall 12 (described in more detail later) to hold a melt (not shown). BP-X0-E122-033-XP-1 New registration EKW GmbH January 26, 2026

[0052] To prevent the molten metal from solidifying in chamber 10, the trough induction furnace 2 has a heating element 16 on its underside as seen in the vertical direction 8. This heating element comprises a block 18 traversed by U-shaped tunnels, called troughs 20, which extend in the vertical direction 8 and in the longitudinal direction 4 and are open upwards into chamber 10, allowing the molten metal to enter the troughs 20. The U-shape of the troughs 20 is not visible in the perspective of Fig. 1.

[0053] Block 18 must be refractory to contain the molten metal in the troughs 20, while simultaneously being capable of generating induction currents (to be described later) to heat the molten metal in the troughs 20. Materials such as magnetite, ferrite ceramics, or chromium-magnesite alloys are suitable for this purpose. During operation, a continuous thermal cycle is created in the U-shaped troughs 20. Cold molten metal sinks to the lower sections of the troughs 20 due to its higher density, while the lighter molten metal, heated by induction, rises into chamber 10. This behavior results in a natural circulation of the molten metal in the U-shaped troughs 20, ensuring uniform mixing and temperature distribution. The induction heating not only provides the necessary heat but also promotes additional movement of the molten metal through the generated induction currents.This cycle prevents the molten metal from solidifying in the channels 20 and keeps the metal in the chamber 10 at a constant temperature.

[0054] To generate the aforementioned induced currents, the U-shaped channels 20 encircle induction loops 22 at the lower end of block 18, as viewed in the vertical direction 8. When energized, the induction loops 22 in block 18 generate induced currents that circulate perpendicularly around the U-shaped channels 20, thus heating block 18 and consequently the molten metal in the U-shaped channels 20 as described. For electrical isolation of the B-P-X0-E122-033-XP-1 New registration EKW GmbH January 26, 2026

[0055] Induction loops 22 from the rest of the block 16 may also have insulators 24 inserted.

[0056] In the operation of the trough induction furnace 2, chamber 10 is first filled with molten metal so that sufficient molten metal can circulate through the U-shaped troughs 20. The remainder of chamber 10 can then be filled with material to be melted. To discharge the molten metal from chamber 10, the trough induction furnace 2 is pivotally mounted about an axis 26 extending in the longitudinal direction 4, allowing it to tilt in and against the transverse direction 6. At its rear side, as viewed in the transverse direction 6, the trough induction furnace 2 has an outlet 28 through which the molten metal is discharged from the chamber if the trough induction furnace 2 is tilted against the transverse direction 6.

[0057] The wall 12 of the trough induction furnace 2, described above, has the task of securely containing the melt in chamber 10. For this purpose, the wall 12 must be sufficiently stable both mechanically and chemically. This is achieved through a multi-layered structure of the wall 12, which will be discussed in more detail below.

[0058] On its outer surface, viewed in the longitudinal direction 4 and the transverse direction 6, the wall has an outer shell 30, whose primary function is to ensure mechanical stability. The outer shell 30 is typically made of a high-strength steel or a similar metal alloy that withstands both the stresses caused by the internal pressure of the melt and thermal expansion. The outer shell 30 may be coated to protect it from corrosion caused by environmental influences. Common materials for the outer shell 20 are galvanized steel, stainless steel, or heat-resistant alloys that do not oxidize or weaken even at high temperatures. A flange 32 is mounted on the outer shell 30 at the top and bottom surfaces viewed in the vertical direction 8.

[0059] The flange 32 extends both inwards and outwards in the longitudinal direction 4 and the transverse direction 6. The outwardly directed part of the flange 32 can serve to stabilize the outer shell 30 when gripping it, for example, with a tool (not shown). The inwardly directed part of the flange 32, together with the rest of the outer shell 30, serves as an enclosure for a thermal protection layer 34, the primary function of which is to ensure a sufficient temperature gradient between the chamber 10 and the outer shell 30 to protect it from thermal damage. This will be discussed in more detail later. The outer shell 30 also has a plate 36 on the underside of the chamber 10 (viewed in the vertical direction 8), onto which the entire trough induction furnace 2 can be stably placed on a frame (not shown) as a base.

[0060] The thermal protection layer 34 is provided on its side facing chamber 10, as viewed in the longitudinal direction 4 and the transverse direction 6, with a coating 38 for protection against chemical attack. The thermal protection layer 34 and the coating 38 will be discussed in more detail later.

[0061] The coating 38 is adjoined on the side facing chamber 10 as seen in the longitudinal direction 4 and the transverse direction 6 by a permanent lining 40 and on that a wear lining 42.

[0062] The permanent lining 40 is a layer directly adjacent to the thermal protection layer 34. Its primary purpose is to create a mechanical decoupling between the thermal protection layer 34 and the melt. It acts as a buffer zone, protecting the thermal protection layer 34 from direct mechanical stresses that can arise from the melt and its movement, internal pressure, and thermal expansion. Unlike the outer shell 30, which provides the overall mechanical stability of the entire trough induction furnace 2, the permanent lining 40 is specifically designed to protect the underlying B-P-X0-E122-033-XP-1 New registration EKW GmbH January 26, 2026

[0063] The layers are structurally relieved of stress and simultaneously serve as a supporting base for the wear lining 42 above. It consists of high-temperature resistant materials such as magnesite (MgO), chromium magnesite (Cr2O3-MgO) or aluminum silicate, which are able to withstand the thermal and mechanical stresses during the long-term operation of the trough induction furnace 2.

[0064] The wear lining 42, on the other hand, is designed as an outer layer that is in direct contact with the melt and withstands the extreme thermal and chemical stresses caused by the melt and slag. Due to regular wear through erosion and corrosion, the wear lining 42 is designed as a sacrificial layer that can be replaced as needed. Typical materials for this are chromite (containing Cr₂O₃), zirconium oxide (ZrO₂), or sintered refractory materials, which are selected depending on the type of melt. The wear lining 42 not only protects against chemical attack from the melt but also prevents high temperatures from damaging the underlying layers, such as the permanent lining 40 or the thermal protection layer 34.

[0065] The thermal protection layer 34 and the coating 38 are described in more detail below. The thermal protection layer 34 is formed from a component system. A component system is a mixture of precisely matched components that react with each other during processing to form the thermal protection layer 34, creating a material with defined properties. The component system includes a refractory aggregate that serves as the base structure, a chemically curing binder to stabilize the structure, and water as the reaction medium. During processing, these components are homogeneously distributed by mixing. The mixed material is then applied to the side of the outer shell 30 facing chamber 10 between the flanges 32 as shown in Fig. 1, for example by pouring, ramming, or spraying.Following the order, the thermal B-P-X0-E122-033-XP-1 new registration EKW GmbH 26 January 2026.

[0066] The protective layer 34 has cured, giving it its final structure with the properties necessary to fulfill its thermal insulation task.

[0067] The following is an example of such a conventional component system:

[0068]

[0069] To produce the thermal protection layer 34 from this conventional component system, the components are first mixed homogeneously to ensure a uniform distribution of all components. The mixed material is then applied to the outer shell 30 as described above and allowed to harden, whereby water, together with the cement in the mixed material, provides mechanical hardening and the basic stability of the thermal protection layer 34 through hydration.

[0070] After curing is complete, excess water is driven out of the thermal protection layer 34 and organic substances are released. This is achieved through slow and controlled heating, which evaporates the water remaining in the cured material and permanently stabilizes the structure of the thermal protection layer 34. Simultaneously, the hydroxypropyl methylcellulose is burned off at higher temperatures.

[0071] Without the evaporation of the excess water and the burning off of the hydroxypropylmethylcellulose, there are significant risks to the structure and functionality of the thermal protection layer 34. The water remaining in the thermal protection layer 34 can, at high temperatures, lead to [B-P-X0-E122-033-XP-1 New registration EKW GmbH 26 January 2026]

[0072] Temperatures during operation of the trough induction furnace 2 can suddenly evaporate, generating stresses within the thermal protection layer 34. These stresses can lead to cracks, instabilities, or even partial disintegration of the thermal protection layer 34. Furthermore, organic residues of the hydroxypropyl methylcellulose remain in the thermal protection layer 34, which could burn uncontrollably at subsequent high temperatures. This could not only impair the mechanical stability but also lead to local weakening, thereby reducing the insulating properties of the thermal protection layer 34. Therefore, failing to drive off the excess water and burn off the hydroxypropyl methylcellulose jeopardizes both the long-term stability and the thermal and mechanical performance of the thermal protection layer 34.

[0073] However, removing the excess water and burning off the hydroxypropyl methylcellulose is time-consuming and energy-intensive. For this reason, a foaming agent, such as the one commercially available under the brand name PANTAPOR® FA, was added to the component system. This will be explained below using two examples.

[0074] In a component system according to a first embodiment, a synthetically produced sulfate in the form of lauryl sulfate (alternatively, but not shown, sodium lauryl sulfate) is added to the conventional component system as a foaming agent:

[0075]

[0076] BP-X0-E122-033-XP-1 New registration EKW GmbH January 26, 2026

[0077] To produce the thermal protection layer 34 from this component system according to the first embodiment, the components of the conventional component system, i.e., without the foaming agent, are first homogeneously mixed to ensure a uniform distribution of all components. Simultaneously, a foam is formed from the foaming agent and water, and this foam is mixed into the outer shell 30 before the mixed material is applied. After the mixed material with the foam is applied to the outer shell 30, the material is allowed to harden by air drying.

[0078] The pores formed during the production of the thermal protection layer 34 by the use of the foaming agent allow the material to dry sufficiently through air drying alone. These pores significantly increase the internal surface area of ​​the thermal protection layer 34, thus allowing the water bound within the thermal protection layer 34 to escape more easily.

[0079] At the same time, the pores ensure an even distribution of moisture within the thermal protection layer 34, so that there is no locally increased moisture that could lead to stresses.

[0080] The evaporation of water during air drying sufficiently establishes the stability of the thermal protection layer 34 without the need for additional thermal processes. A small amount of hydroxypropyl methylcellulose remaining in the thermal protection layer 34 does not negatively affect its thermal and mechanical properties. During subsequent use of the material at high temperatures, these organic substances decompose in a controlled manner without impacting the structural stability. This controlled adjustment of the composition and the carefully designed pore structure eliminate the need for additional thermal processes in the production of the thermal protection layer 34. BP-X0-E122-033-XP-1 New registration EKW GmbH January 26, 2026

[0081] These results were also achieved with a component system according to a second embodiment, in which a polymer-based non-ionic surfactant in the form of polyethylene glycol alkyl ether was added to the conventional component system as a foaming agent:

[0082]

[0083] The three component systems described above underwent a series of investigations to evaluate their performance and properties under controlled conditions. Several tests were conducted to determine the density, drying time, energy consumption, and insulation performance of the materials. The measurements were performed under standardized conditions to ensure comparability.

[0084] For example, density was determined by pouring the material into defined molds, drying it, and weighing it. To account for environmental influences such as temperature or humidity fluctuations, the measurements were repeated under different conditions.

[0085] The drying time was measured under constant ambient conditions at room temperature (approx. 20 °C) and in a stable airflow to ensure uniform water evaporation. The point at which complete drying was achieved, at which no further mass loss was detectable, was determined. Several samples were examined under identical conditions.

[0086] The energy input was calculated by measuring the energy required for processing, drying, and curing and applying it to the B-P-X0-E122-033-XP-1 New registration EKW GmbH January 26, 2026

[0087] The sample volumes were normalized. These measurements were performed both under pure air drying and with the addition of thermal energy to quantify differences in the component systems.

[0088] The insulation performance was determined by measuring the thermal conductivity of the samples. For this purpose, the samples were heated to a defined temperature, and the heat flow through the material was recorded in a calorimeter. These tests were carried out at different temperatures to evaluate the thermal properties of the materials under realistic operating conditions.

[0089] The use of ranges instead of specific measurements results from the variations observed in the different test series. These variations are due to material inhomogeneities, environmental influences, or minor deviations in processing. The ranges therefore reflect the spread of the results and offer a more realistic assessment of the material properties under different conditions. Conducting multiple measurements ensured that the stated values ​​are representative and reliably characterize the performance of the component systems.

[0090] The results of these experiments are shown below:

[0091]

[0092] BP-X0-E122-033-XP-1 New registration EKW GmbH January 26, 2026

[0093] The values ​​for the various component systems show clear differences in their properties and advantages compared to the state of the art. The properties are explained below:

[0094] The density of the state of the art is approximately 2.0–2.2 g / cm³. 3 , since no pore structure is present. The thermal protection layer 34 has a compact structure because no foaming agents are used to loosen the mass. In the component system with lauryl sulfate (Example 1), a moderate pore structure is created by foaming, which increases the density to 1.6–1.8 g / cm³. 3 The density is reduced. When using polyethylene glycol alkyl ether (Example 2), even more efficient pore formation is achieved, thereby reducing the density to 1.4–1.6 g / cm³. 3 further decreases. This reduction in density improves the insulation capacity and lowers the weight of the thermal protection layer 34.

[0095] In the prior art, the drying time of the thermal protection layer 34 is approximately 48–72 hours, achieved without any additional energy input for the drying process. The compact material of the prior art thermal protection layer 34 has a smaller internal surface area, which slows down the evaporation process of the water. In the component system with lauryl sulfate (Example 1), the drying time of the thermal protection layer 34 is reduced to 24–36 hours, as the pores created by the foaming agent significantly facilitate water evaporation. In the component system with polyethylene glycol alkyl ether (Example 2), the drying time of the thermal protection layer 34 is reduced again to 18–30 hours, as the foaming agent creates a more uniform and stable pore structure, enabling faster and more efficient drying.

[0096] In the prior art, the energy input for the production of the thermal protective layer 34 was approximately 20-30 kWh / m². 3 , whereas here, unlike in the recording of drying time, thermal post-treatment processes such as burning or forced drying are not included. B-P-X0-E122-033-XP-1 New registration EKW GmbH January 26, 2026

[0097] were applied. In the component system with lauryl sulfate (Example 1), the thermal post-treatment of the thermal protective layer 34 is completely eliminated, and the energy requirement drops to 10-15 kWh / m². 3 , mainly for mixing and minimal supporting processes. The component system with polyethylene glycol alkyl ether (Example 2) requires even less energy (approx. 8-12 kWh / m²) to produce the thermal protection layer 34. 3 ), as the more uniform pore structure further simplifies material processing.

[0098] The thermal conductivity of the thermal protection layer 34 in the prior art is approximately 0.9–1.2 W / mK, which is due to its dense, non-porous structure. In the component system with lauryl sulfate (Example 1), the thermal conductivity of the thermal protection layer 34 decreases to 0.5–0.7 W / mK, as the pore structure created by the foaming agent reduces heat transfer within the material. In the component system with polyethylene glycol alkyl ether (Example 2), the even more uniform and stable pore formation results in a further improvement in the thermal conductivity of the thermal protection layer 34 to 0.4–0.6 W / mK, thus giving the thermal protection layer 34 excellent insulation performance.

[0099] After the thermal protection layer 34 is completed, the coating 38, made of a ceramic material, preferably an aluminum silicate phase such as mullite, is applied. This step can be carried out in two different ways. First, the ceramic material can be produced separately and then applied to the insulation material. Second, the aluminum silicate phase can be applied directly to the thermal protection layer 34, so that it reacts with the thermal protection layer 34 during curing or operation to form mullite. This second approach has the advantage that the pores of the thermal protection layer 34 are directly sealed, thus preventing the ingress of water or other liquids that could cause problems during the operation of the trough induction furnace 2. BP-X0-E122-033-XP-1 New application EKW GmbH January 26, 2026

[0100] Such a seal protects the underlying layers, such as the permanent lining 40 and the wear lining 42, from damaging influences. Ideally, sufficient sealing of the pores and the chemical stability of the coating would eliminate the need for these lining layers 40 and 42 altogether. This would not only simplify the design but also save material and costs. The choice of method depends on the specific requirements, with direct application of the ceramic material often being preferred, as it ensures a particularly strong bond between the coating and the thermal protection layer 34 and improves the operational reliability of the trough induction furnace 2.

Claims

BP-X0-E122-033-XP-1 New registration EKW GmbH January 26, 2026 Patent claims 1. Component system for use as a water-miscible dry mix for the production of a thermal protective layer (34) in a metallurgical furnace (2) the wall (12) of which separates a chamber (10) from an outer space (14), wherein the thermal protective layer (34) is designed to allow a controlled temperature drop between a chemically protective layer (38) facing the chamber (10) and a mechanically stabilizing outer shell (30), comprising: - a refractory aggregate containing a thermal insulation material selected from a group consisting of aluminium oxide, aluminosilicates, silicon dioxide, magnesia, zirconia or combinations thereof, - a binder containing cement for chemical hardening by reaction with water, and - a foaming agent containing a chemically amphiphilic material, wherein when the dry mixture is mixed with water a hydrophilic part of the amphiphilic material remains in the water, while a hydrophobic part orients itself towards the air or other hydrophobic substances to reduce the surface tension of the water and stabilize air bubbles.

2. Component system according to claim 1, wherein the amphiphilic material of the foaming agent is an organic material.

3. Component system according to claim 2, wherein the organic material of the foaming agent is protein-based, synthetic or polymer-based.

4. Component system according to one of the preceding claims, wherein the thermal insulation material comprises an adhesive sand with at least Contains 60 wt% quartz sand and at least 10 wt% an aluminosilicate, preferably kaolin. BP-X0-E122-033-XP-1 New registration EKW GmbH January 26, 2026 5. Method for producing a wall (12) separating a chamber (10) of a metallurgical furnace (2) from an outer space (14) with a component system according to one of the preceding claims, comprising - Mixing the refractory aggregate with the binder; - Producing a slurry by adding water to the refractory aggregate mixed with the binder; - Formation of a foam from the foaming agent and water; - Forming the thermal protective layer (34) by stirring the foam into the slurry; - Apply the thermal protective layer (34) to the mechanically stabilizing outer shell (30); - Application of the chemically protective layer (38) to the thermal protective layer (34), and - Drying of the thermal protective layer (34).

6. Method according to claim 5, wherein, for the application of the chemically protective layer (38) to the thermal protective layer (34), a ceramic material, preferably an aluminum silicate phase, particularly preferably Mu Hit, is first produced and then applied to the thermal protective layer (34).

7. Method according to claim 4 or 5, wherein the thermal protective layer (34) is air-dried.

8. Method according to any one of claims 5 to 7, wherein the slurry is further produced by adding a phosphate and / or a cellulose.

9. Metallurgical furnace (2) with a wall (12) separating a chamber (10) from an outer space (14), manufactured by a method according to any one of the preceding claims 5 to 9.

10. Metallurgical furnace (2) according to claim 9, wherein the chemically protective layer (38) is used as a hot face layer.

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