Melting furnace based on microwave synergistic heating and basalt fiber drawing equipment

Abstract

The invention provides a melting furnace based on microwave synergistic heating and basalt fiber drawing equipment. The melting furnace comprises a furnace body of a hollow columnar structure; the feeding pipe penetrates through the central position of the top of the melting furnace from top to bottom; the funnel-shaped melt pool is located in the center of the bottom of the melt furnace and penetrates through the bottom of the melt furnace; a bottom opening of the feeding pipe is over against the melt pool; the microwave generators are fixed on the outer side of the furnace body and are as high as the melt pool; the plurality of heating electrodes are fixed in the furnace body and uniformly surround the feeding pipe; the wire drawing bushing plate is detachably fixed at the bottom of the melt pool; a plurality of wire-drawing discharge spouts are arranged on the wire-drawing bushing plate and are used for enabling molten basalt to form stable liquid drops and preliminarily drafting the liquid drops into a fiber prototype. The problems of high energy consumption, non-uniform melting, unstable product quality, environmental pollution and the like in traditional basalt fiber production are effectively solved, and the beneficial effects of remarkable energy conservation, high product quality rate and clean and continuous production are achieved.

Description

Technical Field

[0001] This application belongs to the field of basalt fiber drawing technology, specifically relating to a melting furnace based on microwave synergistic heating and basalt fiber drawing equipment. Background Technology

[0002] Basalt continuous fiber is an inorganic high-performance fiber made from natural basalt ore through high-temperature melting and drawing. Due to its excellent properties such as high strength, high modulus, high temperature resistance, corrosion resistance, and good thermal and sound insulation, it has broad application prospects in aerospace, defense, civil engineering, and automotive lightweighting.

[0003] Currently, the mainstream methods for industrial production of continuous basalt fibers are the "all-electric melting pool furnace method" or the "cuplift furnace-crucible method," the core of which is a melting furnace heated by gas, oil, or resistance heating. These traditional methods have inherent drawbacks: First, external heating via convection and radiation results in high thermal inertia, low thermal efficiency (typically below 30%), and high energy consumption; second, external heating leads to a large temperature gradient within the furnace, causing uneven heating of the raw materials, which can easily result in incomplete melting or localized overheating, leading to uneven melt composition, breakage and fuzzing during fiber drawing, and poor consistency in the mechanical properties of the product; third, gas or oil melting furnaces produce large amounts of pollutants such as CO2 and NOx, which do not meet the requirements of green manufacturing; finally, the high-temperature basalt melt severely corrodes refractory materials, not only shortening the furnace life and increasing maintenance costs, but also causing impurities to contaminate the melt and affect fiber quality.

[0004] In recent years, microwave heating technology, as a novel volumetric heating method, has shown great potential in the field of materials processing. It achieves synchronous heating of the entire material by converting microwave energy into heat energy through the absorption of microwave energy by the material itself, theoretically offering advantages such as rapid heating, energy saving, and cleanliness. However, this technology still faces severe challenges in the industrial application of basalt continuous fiber: First, it is difficult to form a uniform microwave field in large-scale industrial cavities, easily leading to uneven heating of raw materials and affecting melting quality; second, at high-temperature melting conditions of 1400-1500°C, the design of an efficient and stable microwave energy transmission and coupling system is complex, requiring effective prevention of energy reflection that could damage the microwave source; third, the microwave transmission system, temperature sensing elements, and kiln materials must possess extremely high high-temperature resistance and resistance to melt corrosion; finally, a mature and reliable continuous production line solution has not yet been formed for the efficient, stable, and sealed integration of the microwave melting furnace with subsequent fiber drawing equipment. Therefore, developing a microwave melting device that can solve the above problems and achieve efficient, uniform, energy-saving, and clean production of basalt continuous fibers has become an urgent technological breakthrough needed in this field. Summary of the Invention

[0005] The purpose of this application is to overcome the shortcomings of existing technologies, such as high energy consumption, uneven melting, unstable product quality, and environmental pollution.

[0006] To achieve the above objectives, this application proposes a melting furnace based on microwave-assisted heating, comprising: A furnace body with a hollow columnar structure; the furnace body has 4-8 sides; A cylindrical feeding pipe extends from top to bottom through the center of the top of the melting furnace and into the interior of the melting furnace; A funnel-shaped molten material pool is located at the center of the bottom of the molten material furnace and extends through the bottom of the molten material furnace; the bottom opening of the feeding pipe faces the molten material pool. Several microwave generators are fixed on the outside of the furnace body at the same height as the molten material pool to provide the heat required for melting basalt ore; Several heating electrodes are fixed inside the furnace body and evenly surround the feeding pipe; A wire drawing stencil is detachably fixed to the bottom of the molten material pool; the wire drawing stencil has several wire drawing nozzles for forming stable droplets of molten basalt and initially drawing them into fiber rudiments.

[0007] As an improvement to the aforementioned melting furnace, the furnace body is made of multi-layered refractory material, including: The inner layer is made of special high-purity oxide refractory material; A middle layer composed of high-performance thermal insulation material; and The outer layer consists of a metal-sealed housing.

[0008] As an improvement to the aforementioned melting furnace, the microwave generator has a frequency of 915MHz or 2450MHz; each of the microwave generators is equipped with a water-cooled jacket.

[0009] As an improvement to the aforementioned melting furnace, the heating electrode is a silicon molybdenum rod.

[0010] As an improvement to the aforementioned melting furnace, the number of heating electrodes is the same as the number of sides of the melting furnace.

[0011] As an improvement to the aforementioned melting furnace, the feeding pipe is a corundum pipe.

[0012] As an improvement to the above-mentioned melting furnace, the wire drawing baffle is a platinum-rhodium alloy baffle; the two sides of the wire drawing baffle are connected to heating electrodes, and the temperature of the baffle is controlled by voltage regulation; a water-cooling jacket is also provided at the heating electrodes of the wire drawing baffle; the number of wire drawing nozzles is 50-400, the nozzle wall thickness is 2mm, and the inner diameter is 1.4-1.8mm.

[0013] This application also provides a basalt fiber drawing device, including the aforementioned microwave-assisted heating melting furnace; further comprising: a feeding mechanism, a fixing mechanism, a cooling mechanism, a coating mechanism, a winding mechanism, and a control mechanism; wherein... The feeding mechanism is used to continuously and uniformly convey basalt raw materials into the melting furnace, and to achieve quantitative feeding in conjunction with the control mechanism. The fixing mechanism provides rigid support for the entire device; The cooling mechanism includes a device cooling section and a fiber cooling section; the device cooling section is used to provide a cold source for the microwave generator and the drawing screen; the fiber cooling section is located below the drawing screen and is a ring-shaped air-cooling structure used to blow constant temperature cooling air onto the nascent fiber bundle. The coating mechanism includes a wetting agent tank and a roller coater, used to uniformly coat the surface of the cured fiber bundle with a wetting agent; The winding mechanism employs an active double winding head design for winding the generated fibers; The control mechanism includes a control cabinet integrating a PLC and an industrial computer, which collects temperature, flow rate, and speed parameters through sensors and controls the operation of each component.

[0014] Compared with existing technologies, the advantages of this application are: 1. This invention uses microwave volumetric heating combined with electric heating to replace traditional external heating methods, increasing thermal efficiency from less than 30% to over 60%, achieving energy savings of 30%-50% and significantly reducing production costs. Simultaneously, the entire process uses electricity, eliminating emissions of pollutants such as carbon dioxide (CO2) and nitrogen oxides (NOx) from fuel combustion, achieving zero-pollution, zero-emission green and clean production.

[0015] 2. This invention achieves rapid and uniform melting of basalt raw materials through microwave internal heating and optimized furnace structure, fundamentally solving the problems of uneven melt, easy breakage and fuzz caused by the large temperature gradient of traditional kilns. The produced fibers have more stable and consistent mechanical properties, and the rate of high-quality products is greatly improved. Attached Figure Description

[0016] Figure 1 The diagram shown is a structural schematic of a basalt fiber drawing device. Figure 2 The diagram shown is a schematic of the structure of the pyrometallurgical furnace.

[0017] Attached diagram labels: 1. Melting furnace, 2. Feed inlet, 3. Frame, 4. Control system, 6. Support, 7. Base, 8. Coating mechanism, 9. Cooling mechanism, 10. Cooling water outlet pipe, 11. Cooling water inlet pipe, 12. Winding mechanism, 13. Feeding pipe, 14. Silicon molybdenum rod, 15. Microwave generator, 17. Melting pool. Detailed Implementation

[0018] The technical solution of this application will be described in detail below with reference to the accompanying drawings.

[0019] Example 1 This application provides a microwave-assisted heating furnace for fiber drawing of basalt. The furnace is a hollow cylindrical structure with 4-8 sides, and its dimensions are approximately 110×110×220cm (length×width×height). It utilizes microwave heating instead of traditional resistance or gas heating. A cylindrical feeding tube extends from top to bottom through the center of the furnace's top and into the interior. The feeding tube has a diameter of 10-15cm, a thickness of 5mm, and a length of 45cm, and is made of high-temperature resistant corundum. A funnel-shaped molten material pool is located at the center of the furnace's bottom. The bottom opening of the feeding tube faces the molten material pool. The furnace may include a polygonal multilayer refractory material furnace body structure, heating electrodes, a microwave generator, a molten material pool, and a fiber drawing perforator. The furnace body structure can include a three-layer structure: the inner layer can be a crucible made of special high-purity oxide refractory materials (such as corundum, zirconium corundum mullite), with a thickness of 5cm, possessing extremely high temperature resistance and resistance to chemical erosion by basalt melt; the middle layer can be a high-performance heat insulation material (such as polycrystalline alumina fiber blanket), with a thickness of 2cm, to minimize heat loss; the outer layer can be a metal sealed shell, with a thickness of 0.4cm. A microwave generator can be fixedly connected to the lower outer part of the equipment shell at the same height as the melting pool, providing the main heat source for melting the basalt ore, accelerating the melting process and homogenization of the basalt. Each microwave generator is equipped with a water-cooling jacket for cooling. The furnace body has 4-8 sides, and the required number of microwave generators can be designed according to the furnace's capacity and thermal efficiency. The microwave generator frequency can be selected from 915MHz or 2450MHz, and the resonant cavity power is 1kW. Multiple heating electrodes are installed inside the furnace, and the material can be silicon molybdenum rods. The number of silicon molybdenum rods is the same as the number on the sides of the furnace, with one set of silicon molybdenum rods installed on each side, surrounding the feed pipe. These multiple sets of silicon molybdenum rods provide the main energy source in the early stages of melting, maintaining the uniformity of temperature distribution within the furnace. The wire drawing perforator is a platinum-rhodium alloy perforator, installed at the bottom of the molten material pool. The perforator has several wire drawing nozzles (50-400 nozzles, e.g., 50-hole, 100-hole, 200-hole, 400-hole), with a wall thickness of 2mm and an inner diameter of 1.4-1.8mm. These nozzles are used to form stable droplets from the molten basalt and initially draw them into fiber rudiments. Their size is related to the number of nozzles. This design ensures uniform and efficient melting, significantly reducing energy consumption. The two sides of the wire drawing perforator are connected to copper electrodes, and the temperature of the perforator is controlled by voltage regulation to ensure fiber formation and smooth drawing. The heating electrode of the wire drawing plate is also equipped with a water-cooling jacket to ensure that its temperature is maintained within a safe range during operation.

[0020] Example 2 This application also provides a basalt fiber drawing device, including the aforementioned microwave-coated heating melting furnace, as well as a feeding mechanism, a fixing mechanism, a cooling mechanism, a coating mechanism, a winding mechanism, and a control mechanism. The fixing mechanism is used to fix the melting furnace. The cooling mechanism is connected to the melting furnace and is used to cool the microwave generator and the drawing stencil. The coating mechanism is mounted on the fixing mechanism, located 50 cm below the melting furnace. The winding mechanism is mounted on the fixing mechanism, located 50 cm below the coating mechanism. The control mechanism is mounted on the fixing mechanism, located 120 cm above the ground.

[0021] The feeding mechanism includes a sealed hopper, a vibrating feeder, and a screw propeller, which are used to continuously and uniformly convey basalt raw materials into the melting furnace and are linked with the control mechanism to achieve quantitative feeding.

[0022] The fixing mechanism provides rigid support and precise alignment for the entire equipment, forming the foundation for ensuring the stability of the continuous wire drawing process. Its main body is a heavy-duty welded steel frame structure, annealed to eliminate internal stress. Key mounting surfaces (such as the furnace mounting surface and the guide rail mounting surfaces of each mechanism) are precision milled and equipped with high-strength anchor bolt holes to ensure stability and vibration-free operation during long-term high-speed operation. The mechanism also integrates cable trays for all cables and cooling pipes, making the overall equipment neat and safe. The cooling system comprises two parts: device cooling and fiber cooling. Device cooling: Water-cooled jackets are installed at the waveguides and heating electrodes of the drawing spinneret within the microwave generator of the melting furnace to ensure that the temperature is maintained within a safe range during operation. Fiber cooling: This includes 2-5 parallel cooling water pipes installed below the drawing spinneret, near the fiber outlet. This cooling rapidly and uniformly cools and solidifies the high-temperature fiber bundles, forming a stable fiber structure, which is crucial for ensuring the fiber's mechanical properties.

[0023] The coating mechanism is located approximately 50 cm below the melting furnace, precisely positioned after the fiber bundles have solidified and before they are assembled. Its core consists of a precisely controlled sizing tank and a roller coater. A prepared aqueous polymer sizing agent (such as epoxy or silane type) is continuously pumped into the tank, maintaining a constant level through overflow. The high-speed moving fiber bundles make slight contact with the coating roller, thus uniformly coating them with an extremely thin sizing agent film. This film serves to bundle, lubricate, and protect the fibers, preventing fuzz formation in subsequent processes and enhancing the interfacial bonding between the fibers and the composite material. The coating mechanism is a well-established technology and will not be described in detail here.

[0024] The winding mechanism is the final stage in fiber forming, and its performance directly affects the quality of the yarn bobbin. It employs an active winding design and consists of a main shaft drive system and a yarn guide. The drawing machine's main shaft is driven by a servo motor, allowing for stepless speed adjustment within the range of 10-150 m / min while maintaining extremely high stability. The yarn guide ensures that the fibers are wound evenly and neatly onto the yarn bobbin. The winding mechanism is a mature existing technology and will not be described in detail here.

[0025] The control mechanism, the "brain" of the entire equipment, is integrated into a dustproof and splash-proof industrial control cabinet. Its operating interface is mounted at an optimal operating height of approximately 120cm above the ground. It employs a PLC (Programmable Logic Controller) + industrial computer architecture. The control mechanism collects data in real time through sensors integrated into key components (such as infrared thermometers, pressure sensors, and flow meters) and performs precise closed-loop control of the execution units (microwave generator, feeder, water pump, fan, servo motor, etc.). Operators can set and monitor all process parameters (such as temperature, pulling speed, and feed rate) via a touchscreen. The control mechanism features data logging, fault diagnosis, and alarm shutdown functions, ensuring intelligent, visualized, and highly reliable production.

[0026] Example 3 like Figure 1 and Figure 2 As shown, this embodiment provides a basalt fiber drawing device, including a melting furnace 1, a fixing mechanism, a cooling mechanism 9, a coating mechanism 8, a winding mechanism 12, and a control mechanism 4.

[0027] The fixing mechanism includes an upper frame 3, a middle support 6, and a bottom base 7. The base 7 is fixed to the ground with anchor bolts to ensure the stability of the overall equipment during operation. The support 6 is welded and fixed above the base 7, supporting the coating mechanism 8, the winding mechanism 12, and the control mechanism 4. The frame 3 is fixed to the top side of the support 6 by a snap-fit ​​connection.

[0028] The melting furnace 1 is fixed inside the frame 3. Basalt raw material with a particle size of 2-8mm is fed into the melting furnace 1 through the feed inlet 2 and transported to the melting pool 17 through the feeding pipe 13. The heating electrode silicon molybdenum rod 14 and the microwave generator 15 are activated to heat the melting pool 17. After the raw material is completely melted into a homogeneous melt, the melt flows out through the platinum-rhodium alloy perforator. The initially formed fiber filaments are manually pulled and passed through the coating mechanism 8. The coating mechanism 8 is equipped with a rolling wheel. After the fiber filaments come into contact with it, a layer of sizing agent is applied to the surface. This coating protects the fibers and achieves bundle formation. Subsequently, the fibers are pulled into the winding mechanism 12 to complete the continuous drawing and forming process. During equipment operation, the cooling mechanism 9 cools the microwave generator and the drawing perforator through the cooling water outlet pipe 10 and the cooling water inlet pipe 11. In the entire equipment, the detection and control of the operating parameters of the melting furnace 1, the cooling mechanism, the coating mechanism 8, and the winding mechanism 5 are all connected to the PLC control system 4 to achieve automated control.

[0029] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application and are not intended to limit it. Although this application has been described in detail with reference to the embodiments, those skilled in the art should understand that modifications or equivalent substitutions to the technical solutions of this application do not depart from the spirit and scope of the technical solutions of this application, and should all be covered within the scope of the claims of this application.

Claims

1. A melting furnace based on microwave-assisted heating, characterized in that, include: Hollow columnar furnace body; The furnace body has 4-8 sides; A cylindrical feeding pipe extends from top to bottom through the center of the top of the melting furnace and into the interior of the melting furnace; A funnel-shaped molten material pool is located at the center of the bottom of the molten material furnace and extends through the bottom of the molten material furnace; the bottom opening of the feeding pipe faces the molten material pool. Several microwave generators are fixed on the outside of the furnace body at the same height as the molten material pool to provide the heat required for melting basalt ore; Several heating electrodes are fixed inside the furnace body and evenly surround the feeding pipe; and A wire drawing stencil is detachably fixed to the bottom of the molten material pool; the wire drawing stencil has several wire drawing nozzles for forming stable droplets of molten basalt and initially drawing them into fiber rudiments.

2. The melting furnace based on microwave synergistic heating according to claim 1, characterized in that, The furnace body is made of multi-layered refractory material, including: The inner layer is made of special high-purity oxide refractory material; A middle layer composed of high-performance thermal insulation material; and The outer layer consists of a metal-sealed housing.

3. The melting furnace based on microwave synergistic heating according to claim 1, characterized in that, The microwave generator has a frequency of 915MHz or 2450MHz; each microwave generator is equipped with a water-cooling jacket.

4. The melting furnace based on microwave synergistic heating according to claim 1, characterized in that, The heating electrode is a silicon molybdenum rod.

5. The melting furnace based on microwave synergistic heating according to claim 1, characterized in that, The number of heating electrodes is the same as the number of sides of the melting furnace.

6. The melting furnace based on microwave synergistic heating according to claim 1, characterized in that, The feeding pipe is a corundum pipe.

7. The melting furnace based on microwave synergistic heating according to claim 1, characterized in that, The wire drawing baffle is a platinum-rhodium alloy baffle; the two sides of the wire drawing baffle are connected to heating electrodes, and the temperature of the baffle is controlled by voltage regulation; a water-cooling jacket is also provided at the heating electrodes of the wire drawing baffle; the number of wire drawing nozzles is 50-400, the nozzle wall thickness is 2mm, and the inner diameter is 1.4-1.8mm.

8. A basalt fiber drawing device, characterized in that, The furnace includes a microwave-assisted heating furnace as described in any one of claims 1-7; it further includes: a feeding mechanism, a fixing mechanism, a cooling mechanism, a coating mechanism, a winding mechanism, and a control mechanism; wherein, The feeding mechanism is used to continuously and uniformly convey basalt raw materials into the melting furnace, and to achieve quantitative feeding in conjunction with the control mechanism. The fixing mechanism provides rigid support for the entire device; The cooling mechanism includes a device cooling section and a fiber cooling section; the device cooling section is used to provide a cold source for the microwave generator and the drawing screen; the fiber cooling section is located below the drawing screen and is a ring-shaped air-cooling structure used to blow constant temperature cooling air onto the nascent fiber bundle. The coating mechanism includes a wetting agent tank and a roller coater, used to uniformly coat the surface of the cured fiber bundle with a wetting agent; The winding mechanism employs an active double winding head design for winding the generated fibers; The control mechanism includes a control cabinet integrating a PLC and an industrial computer, which collects temperature, flow rate, and speed parameters through sensors and controls the operation of each component.

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