Use, method and device for the production and / or thermal treatment of inorganic raw materials and / or products

Abstract

The invention relates to the use of at least one plasma burner in combination with at least one microwave generator for heating during production and / or thermal treatment of inorganic raw materials and / or products, in particular during thermal treatment, sintering or melting of inorganic raw materials or production, sintering or thermal post-treatment of ceramics, refractory ceramics, technical ceramics, construction ceramics, glass, cement, metals, composite materials or carbon-containing or carbon-bonded products. The invention also relates to a method using at least one plasma burner in combination with at least one microwave generator and to a device for the production and / or thermal treatment of inorganic raw materials and / or products.

Description

[0001] Use, method and apparatus for the production and / or thermal treatment of inorganic raw materials and / or products

[0002] The invention relates to the use of at least one plasma torch in combination with at least one microwave generator for heating during the production and / or thermal treatment of inorganic raw materials and / or products, in particular during the thermal treatment, sintering or melting of inorganic raw materials or the production, sintering or thermal post-treatment of ceramics, refractory ceramics, technical ceramics, construction ceramics, glass, cement, metals, composite materials or carbon-containing or carbon-bonded products, a method using at least one plasma torch in combination with at least one microwave generator and a device for the production and / or thermal treatment of inorganic raw materials and / or products.

[0003] The generation of electricity and hydrogen using renewable energies offers new opportunities for low-carbon or carbon-free high-temperature technologies for the production or thermal treatment of inorganic materials. The sintering of ceramics, refractory ceramics, composite materials, the melting of glass or metallic materials, the production of cement, etc., cause high carbon dioxide emissions due to conventional, energy-intensive sintering and melting processes.

[0004] Numerous types of furnaces serve as furnace units, such as gas furnaces, sintering furnaces, continuous furnaces, tunnel furnaces, rotary kilns, melting furnaces, treatment furnaces, heat holding furnaces, etc.

[0005] Thermal plasmas can be generated technically by inductive coupling of high-frequency fields in the MHz range, by microwave coupling in the GHz range, or by direct current coupling (arc discharges). Depending on the different methods of plasma generation, a distinction is made between direct current, induction, and microwave plasma torches.

[0006] Plasma torches that use electricity as their primary energy source offer enormous potential for low-CO2 or CO2-free high-temperature processes for the production or thermal treatment of inorganic materials. DE 38 73 193 T2 describes a plasma-assisted process for powder production. US 7,189,940 B2 and US 7,638,727 B2 disclose a device and a method for plasma-assisted melting and plasma-assisted heat treatment, respectively. US 2006 / 0057016 A1

[0007] Koiluweit & Uhlemann I patent attorneys

[0008] 2025039959. DOCX describes a plasma-assisted sintering process and system. US 7,445,817 B2 describes a plasma-assisted process for the production of carbon structures. The documents describe the use of a plasma or plasma torch for energy input in high-temperature processes. However, the rapid, high energy input from the plasma torch creates thermomechanical stresses in the furnace assembly, particularly in the refractory lining, which can significantly reduce its service life.

[0009] DE 10 2021 004 675 B4 discloses a device for the thermal treatment, sintering, or melting of inorganic raw materials, or for the thermal post-treatment of ceramics, cements, metals, or composite materials, comprising a furnace unit in which at least one gas burner is combined with a microwave plasma burner. Alternatively, an induction plasma burner is mentioned as an alternative to a microwave plasma burner. Heating is initially carried out using the gas burner from room temperature, and the microwave gas burner is switched on at 200 °C.

[0010] US Patent 2011 / 006 2013 A1 discloses a device for the thermal treatment of carbon-containing materials. The device includes a plasma torch for melting the raw materials and may include other heating devices, e.g., induction heaters.

[0011] DE 10 2022 122 280 A1 discloses a device for the thermal treatment or melting of inorganic raw materials with an electric heating element and a microwave plasma burner.

[0012] DE 10 2009 014 683 A1 discloses a method and a device for keeping melts, in particular metallic melts, liquid. The melt is produced using conventional methods and then thermal energy in the form of microwave radiation is introduced to maintain the melt.

[0013] US 6 362 449 B1 discloses a plasma burner furnace for the combustion of waste with at least one microwave plasma burner, wherein the microwave plasma burner is intended as a more effective alternative to induction plasma burners known from the prior art.

[0014] US 2012 / 0031232 A1 describes a combined microwave heating and plasma / arc heating in separate zones in various processes and plants, including, among others, the joint production of pig iron and high-quality synthesis gas.

[0015] Kailuweit & Uhlemann I patent attorneys

[0016] 2025039959. DOCX In particular, US 2012 / 0031232 A1 describes a microwave heating area and separately a plasma / arc heating area, and an optional induction heating area.

[0017] EP 2 971 488 B1 describes the hydraulic fracturing of underground formations and, in particular, a system, a method, and a device for sintering ceramic proppant particles (inorganic raw material and / or product) used in the hydraulic fracturing of boreholes. EP 2 971 488 B1 describes the use of microwaves in a high-frequency source (138) for sintering proppants as an alternative to long rotary kilns or a plasma torch.

[0018] DE 69 702 241 T2 describes a melting process for granular materials in which the main heat source consists of microwave energy, with further means for generating energy being a plasma or a second microwave source positioned below the cavity (pages 8-9: "The further means can be a plasma, a plasma that forms when the gas-filled cavities within the crucible are exposed to microwave radiation. ..."). DE 69 702 241 T2 discloses that the material is heated by generating a plasma and / or by applying microwave energy to loose material located in the microwave cavity, with the microwave conductors arranged above and below the crucible. The microwave energy can be supplied to the cavity simultaneously with the plasma, or alternatively, the microwave energy can be supplied after a portion of the material within the cavity has melted.A disadvantage of plasma generation in the cavities between the particles is chaotic heating, resulting in inhomogeneous heating and higher energy consumption.

[0019] The task is therefore to provide a low-CO2 or CO2-free process for the thermal treatment of inorganic materials, in which uniform heating is achieved and the risk of rapid overheating ("thermal runaway" phenomenon) is reduced.

[0020] According to the invention, the problem is solved by the method, the product, and the use, as defined in the independent claims. Advantageous embodiments of the invention are specified in the dependent claims.

[0021] A first aspect of the invention relates to a method for the production and / or thermal treatment of inorganic raw materials and / or products using at least one plasma torch, in particular a microwave plasma torch, in combination with at least one microwave generator for heating, in particular for the thermal treatment, sintering or melting of inorganic raw materials or for the production, sintering or thermal post-treatment of ceramics, refractory ceramics, technical

[0022] Kailuweit & Uhlemann I patent attorneys

[0023] 2025039959. DOCX ceramics, building ceramics, glass, cement, metals, composite materials or carbon-containing or carbon-bonded products.

[0024] Advantageously, the plasma burner, particularly a microwave plasma burner, and the microwaves from the microwave generator operate within the same reactor chamber (vessel). This combination advantageously achieves maximum energy efficiency during thermal treatment.

[0025] The advantage of the invention is that the process and the device are fully electrified. This makes it possible to operate exclusively using green electricity. Advantageously, the combination of plasma torches and microwave coupling, when using renewable energy as the primary energy source, leads to CO2-free high-temperature technologies for the production or thermal treatment of inorganic materials. Furthermore, the use of plasma torches and a microwave generator allows for optimization of the space requirements of existing systems, as both plasma and microwave generation can be decoupled from the system, i.e., spatially separated. In particular, transmission via a waveguide is possible. Thus, the system requires less space.The spatial separation also advantageously allows for a reduction in the influence of the system's temperature ("oven temperature") on the microwave generator, especially on the cooling of a magnetron.

[0026] Furthermore, the combination of heating with a plasma torch and microwave coupling advantageously achieves a more homogeneous temperature distribution, thereby reducing thermomechanical stresses (thermal shock). The microwave plasma torch used according to the invention heats the air and achieves uniform heating of the inorganic raw material, ceramic, refractory ceramic, technical ceramic, construction ceramic, glass, cement, metal, composite material, or carbon-containing or carbon-bonded product. This also reduces the thermal load on the unit. With the coupling of microwaves alone, uneven heating and partial overheating often occur. In contrast, with the combination according to the invention, the sample is heated both externally by the plasma torch and internally by the microwaves.Furthermore, the combination according to the invention reduces the risk of rapid overheating (“thermal runaway” phenomenon) of the inorganic raw materials or products.

[0027] Kailuweit & Uhlemann I patent attorneys

[0028] 2025039959. DOCX In embodiments, at least one plasma torch is used in combination with at least one microwave generator for heating during a thermal treatment, sintering or melting of at least one inorganic raw material or a production, sintering or thermal post-treatment of at least one ceramic, refractory ceramic, technical ceramic, construction ceramic, glass, cement, metal, composite material or carbon-containing or carbon-bonded product.

[0029] According to the invention, the process for the production and / or thermal treatment of inorganic raw materials and / or products, in particular for the thermal treatment, sintering or melting of inorganic raw materials or for the production, sintering or thermal post-treatment of ceramics, refractory ceramics, technical ceramics, construction ceramics, glass, cement, metals, composite materials or carbon-containing or carbon-bonded products, comprises the following steps: a. Heating at least one inorganic raw material, a ceramic, refractory ceramic, technical ceramic, construction ceramic, glass, cement, metal, composite material or carbon-containing or carbon-bonded product by means of at least one plasma torch, in particular a microwave plasma torch, and b. Coupling of microwave radiation, wherein the heating in step a. precedes the coupling of microwaves in step b.This involves thermal treatment, sintering or melting of the at least one inorganic raw material or the production, sintering or thermal post-treatment of the ceramic, refractory ceramic, technical ceramic, construction ceramic, glass, cement, metal, composite material or carbon-containing or carbon-bonded product.

[0030] The term "plasma torch" refers to a device for generating a directed plasma stream (electric arc) for cutting or burning materials or workpieces. "Plasma" is an electrically conductive gas with a temperature of approximately 30,000 °C. The arc is advantageously ignited by a high-frequency ignition system. In some embodiments, the gas is compressed air. In other embodiments, the plasma stream is constricted at the outlet of the plasma torch by an insulated, preferably water-cooled, copper nozzle.

[0031] The plasma torch is significantly more efficient in terms of heat transfer than an electric heating element. The process also benefits from the use of combustible materials.

[0032] Kailuweit & Uhlemann I patent attorneys

[0033] 2025039959. DOCX gases are omitted. This also applies to the otherwise necessary safety precautions such as explosion protection devices.

[0034] Another advantage is that the plasma torch can be attached to existing high-temperature systems.

[0035] According to the invention, the plasma torch is a microwave plasma torch. The term "microwave plasma torch" refers to a plasma torch in which microwaves generate a plasma. In embodiments, the microwave plasma torch comprises a microwave generator, preferably comprising a magnetron. The term "magnetron" refers to a device, in particular a vacuum transit-time tube, for generating electromagnetic waves in the microwave range, especially from approximately 0.3 GHz to 95 GHz.

[0036] In embodiments, step a. involves the use of at least one plasma torch to thermally treat, sinter, coke, pyrolyze, melt, or oxidize inorganic raw materials, ceramics, refractory ceramics, glass, cement, metals, composite materials, or carbon-containing or carbon-bonded products. Advantageously, the combination according to the invention can achieve a denser sintering.

[0037] In various embodiments, the inorganic raw materials include carbon. The term "carbon-containing" refers to products containing carbon as a substance, such as graphite or carbon black, or as a compound, such as silicon carbide or boron carbide. The term "carbon-bonded" refers to products containing at least one carbon-containing binder.

[0038] In some embodiments, the inorganic raw materials include organic additives. In other embodiments, the organic additives are selected from the group consisting of binders, liquefiers, and stabilizers.

[0039] The term "sintering" refers to heat treatment at a temperature below the melting point of the materials to be treated, preferably in the range of 0.5 to 0.8 times the melting point; particularly preferably at a temperature corresponding to 2 / 3 (or 0.67 times) the melting point (±10 K).

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[0041] 2025039959. DOCX The term "coking" refers to a heat treatment in the exclusion of air at temperatures in the range of 600 °C to 1400 °C, whereby the volatile components are driven off and partially thermally split or carbon phases are formed.

[0042] The term "pyrolysis" refers to a heat treatment in the absence of oxygen at temperatures in the range of 150 °C to 700 °C, in which organic compounds are reacted.

[0043] The term "melting" refers to a heat treatment in which a phase transition of a solid substance or mixture of substances into the liquid state takes place.

[0044] The term "oxidation" refers to a chemical reaction in which an ion or atom (as part of a molecule) gives up electrons, in particular in which a molecule absorbs oxygen.

[0045] The term "ceramics" refers to inorganic, non-metallic materials that are shaped using a primary forming process and subsequently sintered. Ceramics that, according to DIN 51 060, have a cone deformation point greater than SK 17 (= ISO 150), i.e., 1500 °C, are designated as "refractory ceramics," whereby the cone deformation point generally coincides with the softening point.

[0046] In various embodiments, the ceramic or refractory ceramic consists of Al₂O₃, ZrO₂, C₅O₃, SiO₂, MgO, MgAhO₄, LaO₂O₃, TiO₂, CaO, LaCrO₃, CaZrO₃, SiC, B₄C, ZrB₂, SiSN₄, Al₂, C, BaO, BaTiO₃, or mixtures thereof, preferably of Al₂O₃, ZrO₂, MgO, MgAhO₄, TiO₂, CaO, C, or mixtures thereof. Preferably, the refractory ceramic comprises at least one metal with a melting point above 600 °C, in particular Cu, Fe, Si, Ni, Ti, Al, or Mg.

[0047] Technical ceramics are ceramic materials whose properties have been optimized for technical applications, e.g., zirconium dioxide ceramics made from ZrÜ2.

[0048] The term "building ceramics" refers to building components made from ceramic materials, which are used constructively or decoratively in buildings, in particular bricks, roof tiles, clinker bricks, tiles, stove tiles and clay pipes.

[0049] Kailuweit & Uhlemann I patent attorneys

[0050] 2025039959. DOCX The term "composite material" (also composite material, or simply composite) refers to a mixture of two or more pure base materials, at least one of which forms a continuous phase.

[0051] In some embodiments, the composite material consists of a ceramic and a metallic component, particularly with or without carbon, or of different types of carbon. In other embodiments, the metallic component of the composite material is selected from steel, iron, iron and steel alloys, aluminum and aluminum alloys, copper, nickel, or refractory metals. Refractory metals are understood to be high-melting-point, base metals, in particular those of group 4 (titanium, zirconium, and hafnium), group 5 (vanadium, niobium, and tantalum), and group 6 (chromium, molybdenum, and tungsten).

[0052] In embodiments, the heating in step a. takes place in a container which is at least partially microwave-transparent, preferably with a lining, in particular in an oven unit, a treatment unit, a ladle, a distributor or a reactor unit.

[0053] In embodiments, the furnace unit is selected from the group comprising gas furnaces, sintering furnaces, continuous furnaces, tunnel furnaces, shaft furnaces, rotary kilns, melting furnaces, treatment furnaces, heat holding furnaces, preheating furnaces, crucible furnaces, induction crucible furnaces, waste incineration furnaces, reactors, in particular coking reactors and cracking reactors.

[0054] In some embodiments, heating is combined with the coupling of microwaves by at least one microwave plasma burner and the coupling of microwaves by at least one microwave generator, and furthermore, heating is combined with the coupling of microwaves by at least one induction plasma burner. Advantageously, no plasma is ignited when microwaves are coupled in by the at least one microwave generator.

[0055] In some embodiments, microwaves are coupled in by means of at least one waveguide connected to a microwave generator. A "waveguide" is understood to be an element for transporting waves from one location to another, particularly for transmitting energy in the form of electromagnetic waves. It is therefore advantageous for the microwave generation location to be different from the application location, which reduces the system's footprint and minimizes the influence of the system's temperature on the microwave generator.

[0056] Kailuweit & Uhlemann I patent attorneys

[0057] 2025039959. DOCX In some embodiments, the waveguide is a hollow conductor or coaxial cable. The term "hollow conductor" refers to a waveguide for electromagnetic waves, primarily in the frequency range of 1 to 1500 GHz. In some embodiments, the hollow conductor is a metal tube with a rectangular, circular, or elliptical cross-section. The term "coaxial cable" refers to a two-core cable with a concentric cross-section, consisting of an inner conductor surrounded at a constant distance by a hollow cylindrical outer conductor. The space between the conductors is an insulator or dielectric.

[0058] In embodiments, the waveguide is connected to a container in which the heating takes place in step a.

[0059] In some embodiments, the microwave generator includes a magnetron.

[0060] In some embodiments, microwaves are coupled in at a frequency in the range of 300 MHz to 300 GHz.

[0061] In embodiments, microwaves are coupled in for a duration in the range of 0.5 min to 24 h, preferably in the range of 0.5 min to 60 min.

[0062] According to the invention, the heating takes place in step a. before the coupling of microwaves in step b.

[0063] Advantageously, at least one plasma torch serves as a thermal energy source for the gentle heating of the furnace chamber. In step a., the temperature of the inorganic raw material, ceramic, refractory ceramic, technical ceramic, construction ceramic, glass, cement, metal, composite material, or carbon-containing or carbon-bonded product is expediently increased, thereby raising its dielectric constant. Advantageously, high sintering or melting temperatures can be achieved by the subsequent coupling of microwaves.

[0064] In embodiments, the microwave plasma burner is switched off in step b., resulting in direct microwave coupling.

[0065] Kailuweit & Uhlemann I patent attorneys

[0066] 2025039959. DOCX In embodiments, the at least one plasma torch is switched off at a temperature in the range of 200 °C to 1,600 °C, preferably in the range of 200 °C to 1,400 °C, and particularly preferably in the range of 600 °C to 1,400 °C or 200 °C to 1,200 °C. Advantageously, a microwave generator can be used for generating microwaves and for plasma generation during the heating process in step a., either before or after the coupling of microwaves in step b.

[0067] In some embodiments, heating in step a. is additionally carried out using an induction plasma burner before the coupling of microwaves in step b. In other embodiments, in step b. the at least one induction plasma burner is switched off, and direct microwave coupling is carried out by switching on a microwave generator, which transmits the microwaves by means of at least one waveguide.

[0068] In embodiments, heating in step a. takes place up to a temperature of 25% of the melting temperature (T). m ) of an inorganic raw material, preferably up to a temperature of 2 / 3 (67%) of the melting temperature (T m ), particularly preferably up to a temperature of 90% of the melting temperature (T m ) of an inorganic raw material, and subsequently the coupling of microwaves in step b.

[0069] In embodiments, heating takes place in step a. up to a temperature of 200 °C, preferably up to a temperature of 300 °C, particularly preferably up to a temperature of 400 °C, and then the coupling of microwaves takes place in step b.

[0070] In embodiments, the heating in step a. takes place until an inorganic raw material melts, i.e., until the melting temperature (T) is reached. m) of an inorganic raw material, and subsequently the coupling of microwaves in step b. to maintain the melting temperature. In embodiments, the at least one plasma torch is switched off in step b. Advantageously, the direct microwave coupling in the melt can maintain the melting temperature.

[0071] In embodiments, the method, wherein the heating in step a. takes place before the coupling of microwaves in step b., is used for sintering ceramics, metals, composite materials or material combinations and / or for melting metals, ceramics or slags. In preferred embodiments, the method, wherein the heating in step a. takes place before the coupling of microwaves in step b., is used for melting

[0072] Kailuweit & Uhlemann I patent attorneys

[0073] 2025039959. DOCX of metals, glass, or slags. Advantageously, heating a metal or glass in step a. enables subsequent coupling of microwaves.

[0074] In embodiments, heating by means of a plasma torch takes place simultaneously with the coupling of microwaves in step b.

[0075] In embodiments, the simultaneous heating and coupling of microwaves is carried out by means of at least one microwave plasma torch and additional microwave generator, and thus with at least two microwave generators, or by means of at least one induction plasma torch and a microwave generator.

[0076] In embodiments, the method, wherein the heating takes place simultaneously with the coupling of microwaves in step b., is carried out for special microstructure formations, in particular for fibrous microstructure formations.

[0077] The number of plasma torches is appropriately determined based on the required power and the size of the container, in particular the furnace unit.

[0078] In embodiments, the heating in step a. is carried out with at least two plasma torches, preferably with at least ten plasma torches, and particularly preferably with at least 100 plasma torches. Advantageously, the at least two plasma torches are evenly distributed around or in a container in which the heating takes place, or around or in a lining of the container.

[0079] In some embodiments, the process uses a combination of microwave plasma burners and induction plasma burners. Microwave plasma burners offer the advantage of reduced space requirements. Induction plasma burners are particularly stable.

[0080] In embodiments, the heating in step a. is carried out with at least one plasma torch and at least one induction plasma torch, preferably with at least ten plasma torches and at least one induction plasma torch, and particularly preferably with at least 100 plasma torches and at least ten induction plasma torches. Advantageously, the at least one plasma torch and the at least one induction plasma torch are evenly distributed around or in a container in which the heating takes place, or around or in a lining of the container.

[0081] Kailuweit & Uhlemann I patent attorneys

[0082] 2025039959. DOCX In embodiments, the method is carried out with a microwave generator which is connected to at least two microwave plasma torches, preferably to at least four microwave plasma torches, via a waveguide system, in particular a waveguide system.

[0083] In embodiments, the method is carried out with two microwave generators, wherein one microwave generator is connected to at least two microwave plasma torches, preferably at least four microwave plasma torches, via a waveguide system, in particular a waveguide system, and the second microwave generator is connected to a container in which the heating takes place via a second waveguide system, in particular a second waveguide system.

[0084] In embodiments, the method is carried out with two microwave generators, each of which is connected to at least two microwave plasma torches, preferably to at least four microwave plasma torches, via a waveguide system, in particular a waveguide system.

[0085] In embodiments, at least one passive or active catalyst is added in step a., which assists the heating process using a plasma torch. In embodiments, active or passive catalysts are nanoscale titanium dioxide powders, carbon black, or carbon nanotubes.

[0086] In some embodiments, heating is additionally carried out by at least one electric heating element and / or induction field.

[0087] In some embodiments, additional heating is carried out by at least one further burner, in particular a gas burner, preferably a hydrogen burner and / or a natural gas burner.

[0088] Another aspect of the invention relates to a device for the production and / or thermal treatment of inorganic raw materials and / or products, in particular for the thermal treatment, sintering or melting of inorganic raw materials or for the production, sintering or thermal post-treatment of ceramics, refractory ceramics, technical ceramics, construction ceramics, glass, cement, metals, composite materials or carbon-containing or carbon-bonded products, comprising

[0089] Kailuweit & Uhlemann I patent attorneys

[0090] 2025039959. DOCX i. at least one container for holding inorganic raw materials, ceramics, refractory ceramics, technical ceramics, construction ceramics, glass, cement, metals, composite materials or carbon-containing or carbon-bonded products, which is at least partially microwave-transparent, ii. at least one plasma torch, in particular a microwave plasma torch, and iii. at least one microwave generator.

[0091] The container is advantageously fireproof and at least partially microwave-transparent. To prevent corrosion, the container is advantageously designed not to interact with microwave radiation; that is, it does not couple to the microwaves and therefore does not heat up. In various embodiments, the container is made of a metallic or non-metallic material.

[0092] In some embodiments, the container has a refractory and / or heat-insulating lining on or in which at least one plasma torch is arranged. In some embodiments, the refractory and / or heat-insulating lining consists of glass, glass fiber materials, ceramic, fiber-reinforced ceramic materials, or a refractory metal.

[0093] In embodiments, the refractory and / or heat-insulating lining consists of fine grains, in particular crystallite sizes smaller than 100 pm, and / or coarse grains, in particular crystallite sizes greater than or equal to 100 pm.

[0094] In some embodiments, the thickness of the lining ranges from 1 mm to 1 m.

[0095] In various embodiments, the container is either stationary or mobile.

[0096] In various embodiments, the container is a furnace unit, treatment unit, ladle, distributor or reactor unit.

[0097] In embodiments, the microwave generator is connected to the at least one container via a waveguide.

[0098] In some embodiments, the microwave generator has a cooling system.

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[0100] 2025039959. DOCX In embodiments, the device according to the invention is used for heating during the production and / or thermal treatment of inorganic raw materials and / or products.

[0101] For the realization of the invention, it is also advantageous to combine the aforementioned inventive configurations, embodiments and features of the claims.

[0102] Examples of implementation

[0103] The invention will now be explained in more detail using an exemplary embodiment. This exemplary embodiment will describe the invention without limiting its scope.

[0104] The invention is explained in more detail with the aid of drawings. These drawings show

[0105] Fig. 1 shows a scheme of a device according to the invention comprising a microwave generator 2 with a waveguide, in particular a waveguide system 3, for the microwave plasma burners 4 and for the microwave coupling (unignited plasma).

[0106] Fig. 2 shows a scheme of a device according to the invention comprising two microwave generators 2a, 2b, each with a waveguide system, in particular a waveguide system 3a, 3b, for the microwave plasma burners 4 (microwave generator 2a and waveguide system 3a) or for the microwave coupling (unignited plasma, microwave generator 2b and waveguide system 3b).

[0107] Fig. 3 shows a scheme of a device according to the invention comprising two microwave generators 2a, 2b each with a waveguide system, in particular a waveguide system 3a, 3b, both for the microwave plasma burners 4 and for the microwave coupling (unignited plasma).

[0108] Fig. 4 shows a schematic of a device according to the invention comprising two

[0109] Microwave generators 2a, 2b each with a waveguide system, in particular a waveguide system 3a, 3b, both for the microwave plasma torches 4 (8 microwave plasma torches) and for microwave coupling (unignited plasma).

[0110] Fig. 5 shows a schematic of a device according to the invention comprising a microwave generator 2 with a waveguide, in particular a waveguide system 3, for the microwave plasma torches 4 and for microwave coupling (not

[0111] Kailuweit & Uhlemann I patent attorneys

[0112] 2025039959. DOCX ignited plasma). The device further comprises an induction plasma burner 5.

[0113] Combination of microwave plasma torch and microwave generator

[0114] The microwave generator, in particular the magnetron (2), is located at a distance from the furnace (1) as shown in Fig. 1 and is connected to the furnace (1) by metal waveguides (3). The microwaves are either ignited and used for the burner function (plasma burner) or couple directly to the raw material or product without plasma ignition. Advantageously, this reduces the space requirements of existing systems, the magnetron is cooled far from the furnace, and the magnetron temperature is not affected by the furnace radiation.

[0115] Fig. 1 shows the device for combining a microwave plasma torch and microwave coupling sequentially. The devices according to the invention, as shown in Figs. 2 and 3, with two microwave generators (2a, 2b), enable the simultaneous combination of a microwave plasma torch and microwave coupling, but can also be used for sequential combination.

[0116] Fig. 2 and Fig. 3 differ in that in Fig. 2 a microwave generator (2b) is directly connected to the oven via the second waveguide system (3b) and in Fig. 3 both microwave generators (2a, 2b) are each connected to the plasma torches via a waveguide system (3a, 3b).

[0117] Figure 4 shows a system that includes additional plasma torches.

[0118] Figure 5 shows a system that additionally includes an induction plasma burner.

[0119] Production of a metal melt

[0120] Metals, especially aluminum, copper, or steel, are heated using a plasma torch, particularly a microwave plasma torch, in a 100-liter crucible with 100 kW up to a temperature of 660 to 700°C for aluminum, 1200°C for copper, and 1550°C for steel. Subsequently, microwaves of 30 to 40 kW are applied.

[0121] The combination of plasma torches, especially microwave plasma torches, and subsequent microwave coupling results in uniform heating of the melt, thereby significantly reducing energy consumption.

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[0123] 2025039959. DOCX In alternative embodiments, the production of a partial melt of metals, in particular aluminium, copper or steel, is carried out using a plasma torch, in particular a microwave plasma torch, in a 100 l crucible with 100 kW up to a temperature of about 600°C for aluminium, 1000 to 1100°C for copper and about 1400°C for steel and subsequently the coupling of microwaves with 30 to 40 kW.

[0124] Kailuweit & Uhlemann I patent attorneys

[0125] 2025039959. DOCX reference

[0126] 1 oven

[0127] 2 microwave generators

[0128] 2a first microwave generator

[0129] 2b second microwave generator

[0130] 3 Waveguides, especially hollow conductors

[0131] 3a first waveguide system

[0132] 3b second waveguide system

[0133] 4 microwave plasma burners

[0134] 5 induction plasma burners

[0135] Kailuweit & Uhlemann I patent attorneys

[0136] 2025039959. DOCX

Claims

Patent claims 1. A process for the production and / or thermal treatment of inorganic raw materials and / or products, comprising the following steps: a. Heating at least one inorganic raw material, ceramic, refractory ceramic, technical ceramic, construction ceramic, glass, cement, metal, composite material or carbon-containing or carbon-bonded product by means of at least one plasma torch, in particular a microwave plasma torch, and b. Coupling of microwave radiation, wherein the heating in step a. takes place before the coupling of microwaves in step b., wherein thermal treatment, sintering or melting of the at least one inorganic raw material or the production, sintering or thermal post-treatment of the ceramic, refractory ceramic, technical ceramic, construction ceramic, glass, cement, metal, composite material or carbon-containing or carbon-bonded product takes place.

2. Method according to claim 1, characterized in that the coupling of microwaves is carried out by means of at least one waveguide which is connected to a microwave generator.

3. Method according to claim 1 or 2, characterized in that the coupling of microwaves with a frequency in the range of 300 MHz to 300 GHz takes place.

4. Method according to one of claims 1 to 3, characterized in that the heating in step a. is carried out up to a temperature of 25% of the melting temperature (Tmelting). m ) of an inorganic raw material and subsequently the coupling of microwaves in step b.

5. Method according to one of claims 1 to 4, characterized in that the heating in step a. is carried out up to a temperature of 200 °C and subsequently the coupling of microwaves in step b.

6. Method according to any one of claims 1 to 5, characterized in that the heating in step a. prior to the coupling of microwaves in step b. for sintering of Kailuweit & Uhlemann I patent attorneys 2025039959. DOCX Ceramics, metals, composite materials or material combinations and / or the melting of metals, ceramics or slags takes place.

7. Method according to one of claims 1 to 5, characterized in that the heating in step a. takes place before the coupling of microwaves in step b. for melting metals, glass or slags.

8. Device for the production and / or thermal treatment of inorganic raw materials and / or products, comprising i. at least one container for receiving inorganic raw materials, ceramics, refractory ceramics, technical ceramics, construction ceramics, glass, cement, metals, composite materials or carbon-containing or carbon-bonded products, which is at least partially microwave-transparent, ii. at least one plasma torch, in particular a microwave plasma torch, and iii. at least one microwave generator.

9. Device according to claim 8, characterized in that the container has a fire-resistant and / or heat-insulating lining on which or in which the at least one plasma torch is arranged.

10. Device according to claim 8 or 9, characterized in that the microwave generator is connected to the at least one container via a waveguide.

11. Device according to one of claims 8 to 10, characterized in that the microwave generator has a cooling system.

12. Use of a device according to any one of claims 8 to 11 for heating during the manufacture and / or thermal treatment of inorganic raw materials and / or products. Kailuweit & Uhlemann I patent attorneys 2025039959. DOCX

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