Method for microcapsule synergistic electromagnetic induction heating of metallic gallium and access method

Abstract

This invention relates to the field of gallium heating, and provides a method and access method for microcapsule-assisted electromagnetic induction heating of gallium. The method includes: surrounding an induction coil around the periphery of a gallium storage device with a gap between them; storing solid gallium metal within the gallium storage device, where magnetic microcapsules are distributed internally; and applying a discontinuous pulsed alternating current to the induction coil, causing eddy current heating and hysteresis loss heating effects in the magnetic microcapsules within the gallium storage device, as well as eddy current heating effects in the solid gallium metal, thereby heating and melting the solid gallium metal without damaging the gallium storage device or the magnetic microcapsules. Applying pulsed alternating current to the induction coil causes both the gallium metal and the magnetic microcapsules to generate heat. The magnetic microcapsules promote the dispersion of heating points and enhance heat transfer between gallium metals, effectively shortening the melting time of the gallium metal. By adjusting the parameters of the pulsed alternating current, the heating temperature of the gallium metal can be precisely controlled, preventing damage to the gallium storage device and the magnetic microcapsules, and avoiding contamination of the gallium metal.

Description

Technical Field

[0001] This invention relates to the field of gallium heating technology, and in particular to a method and access method for microcapsule-assisted electromagnetic induction heating of gallium. Background Technology

[0002] Gallium is an important basic semiconductor material, widely used in electronic materials, optoelectronic materials, optical materials, and thermoelectric materials. In the production and application of gallium, it is typically stored in plastic drums or bottles and solidified at relatively low temperatures for easy transportation and storage.

[0003] When handling and processing gallium, solid gallium needs to be melted into liquid gallium. The common heating method involves baking the gallium in an oven. However, due to the large volume of gallium during transport, the overall melting process is lengthy, and oversaturation may occur. This means that some gallium may have already melted and reached a high temperature, while the remaining solid gallium struggles to melt further, further slowing down the melting process. Furthermore, oven heating involves heat transfer from the outside in. The outer gallium melts and forms a liquid surrounding layer, making the inner solid gallium more difficult to melt. To continue melting the inner gallium, higher temperatures may be needed, which poses a challenge to the plastic containers / bottles used to hold the gallium. Excessive temperatures (e.g., exceeding 90 degrees Celsius) can damage the plastic containers / bottles, contaminating the gallium. Summary of the Invention

[0004] The present invention provides a method and access method for microcapsule-assisted electromagnetic induction heating of gallium metal, which at least solves the problems of long melting time and easy contamination of gallium metal in related technologies.

[0005] According to an embodiment of a first aspect of the present invention, a method for microcapsule-assisted electromagnetic induction heating of gallium metal is provided, comprising: surrounding an induction coil on the outer periphery of a gallium storage device, wherein there is a gap between the induction coil and the gallium storage device, and magnetic microcapsules are distributed inside the solid gallium metal stored in the gallium storage device; passing a discontinuous pulsed alternating current through the induction coil to cause eddy current heating and hysteresis loss heating effects in the magnetic microcapsules in the gallium storage device, and eddy current heating effects in the solid gallium metal, so as to heat and melt the solid gallium metal without damaging the gallium storage device and the magnetic microcapsules.

[0006] As an optional approach, it also includes at least one of the following: adding a plurality of magnetic microcapsules that do not contaminate gallium to a gallium storage device containing liquid gallium metal, and then cooling to form solid gallium metal with magnetic microcapsules distributed inside; or, after all the solid gallium metal in the gallium storage device has melted into liquid gallium metal, separating the magnetic microcapsules and liquid gallium metal into solid and liquid states.

[0007] As an alternative, the magnetic microcapsule comprises: a magnetic core; a non-magnetic shell located outside the magnetic core and forming a closed structure; the non-magnetic shell does not contaminate the metallic gallium within a preset temperature range; wherein, the plurality of magnetic microcapsules have density differences and distribution position differences within the liquid metallic gallium, the distribution position differences including at least one of depth dimension and planar coordinate dimension.

[0008] Optionally, magnetic microcapsules of different densities can be obtained by adjusting the volume ratio difference between the non-magnetic shell and the magnetic core or by selecting different materials.

[0009] Optionally, a first microcapsule, a second microcapsule, and a third microcapsule with different densities are prepared; wherein the density of the first microcapsule is less than the density of the liquid gallium metal, the density of the second microcapsule is equal to the density of the liquid gallium metal, and the density of the third microcapsule is greater than the density of the liquid gallium metal.

[0010] Optionally, the density of the above magnetic microcapsules is 5.9 g / cm³. 3 -6.15g / cm 3 .

[0011] Optionally, the diameter of the magnetic microcapsules is 0.2 mm to 0.4 mm.

[0012] Optionally, the volume ratio of the magnetic core to the magnetic microcapsule is 74.6%-78%.

[0013] Optionally, the magnetic core may be selected from at least one of the following materials: Fe3O4, γ-Fe2O3, iron, cobalt, nickel, neodymium iron boron alloy, or ferrite ceramic.

[0014] Optionally, the non-magnetic shell may be made of at least one of the following materials: silicone rubber, perfluoroether rubber (FFKM), polytetrafluoroethylene (PTFE), alumina ceramic, zirconium oxide ceramic, boron nitride ceramic, borosilicate glass, or quartz silicon glass.

[0015] As an optional solution, it further includes at least one of the following: when the pulsed alternating current has not yet been applied to the induction coil, ultrasonic treatment is performed on the solid gallium metal in the gallium storage device based on a first ultrasonic wave, and the microcrack network is generated inside the solid gallium metal using the acoustic cavitation effect; or, when the pulsed alternating current has been applied to the induction coil, ultrasonic treatment is performed on the solid gallium metal and the molten liquid gallium metal in the gallium storage device based on a second ultrasonic wave, and the solid gallium metal and the liquid gallium metal are stirred using the acoustic flow effect; wherein the sound intensity of the second ultrasonic wave is less than the sound intensity of the first ultrasonic wave.

[0016] As an optional configuration, the frequencies of the first and second ultrasonic waves are 20kHz-40kHz, and the sound intensity of the first ultrasonic wave is 1.5W / cm². 2 -2.5W / cm 2 The sound intensity of the second ultrasonic wave mentioned above is 0.8 W / cm². 2 -1.2W / cm 2 .

[0017] As an alternative, the induction coil is arranged around the outer periphery of the gallium storage device, including: providing a housing with an insulation layer on the inner wall of the housing; arranging the induction coil inside the insulation layer; and placing the gallium storage device containing solid gallium metal and magnetic microcapsules distributed within the solid gallium metal inside the housing, so that the induction coil is arranged around the outer periphery of the gallium storage device.

[0018] As an optional solution, the method further includes: detecting the outer wall temperature of the gallium storage device; when the outer wall temperature is less than a preset temperature threshold, adjusting the output power of the pulsed alternating current according to the temperature difference between the outer wall temperature and the preset temperature threshold, so as to control the heating temperature of the gallium metal within a preset temperature range; wherein the preset temperature range corresponds to a temperature higher than the melting temperature of the gallium metal and lower than the smaller of the destruction temperature of the gallium storage device and the destruction temperature of the magnetic microcapsule; the preset temperature threshold is an upper temperature limit obtained by calculating the heating temperature of the gallium metal after heat conduction of the gallium storage device; when the outer wall temperature reaches the preset temperature threshold or the cumulative energization time of the coil exceeds a set time, stopping the pulsed alternating current from being supplied to the induction coil.

[0019] As an optional approach, the method further includes: performing in-situ ultrasonic testing on the gallium metal in the gallium storage device to determine the current state of the gallium metal; if the current state of the gallium metal is a solid-liquid coexistence state, removing the gallium storage device and pouring out the liquid gallium metal, then returning the gallium storage device to its original position and continuing to supply the pulsed AC current to the induction coil to continue heating the remaining solid gallium metal in the gallium storage device; or, if the current state of the gallium metal is a solid-liquid coexistence state, continuously supplying the pulsed AC current to the induction coil to continue heating the remaining solid gallium metal in the solid-liquid coexistence state in the gallium storage device; if the current state of the gallium metal is liquid, removing the gallium storage device and pouring out the liquid gallium metal from the gallium storage device.

[0020] As an optional approach, in-situ ultrasonic testing is performed on the gallium metal in the aforementioned gallium memory device to determine its current state. This includes: with an induction coil surrounding the gallium memory device, transmitting a sound at a frequency of 1MHz to 4MHz and an intensity of 5mW / cm into the gallium memory device. 2 -30mW / cm 2 The third ultrasonic wave is received; the reflected echo of the third ultrasonic wave is received; and the current state of gallium is determined based on the changes in the echo characteristics of the reflected echo.

[0021] According to an embodiment of a second aspect of the present invention, a method for accessing metallic gallium is also provided, comprising: adding a plurality of magnetic microcapsules that do not contaminate gallium into a gallium storage device storing liquid metallic gallium, and then cooling to form solid metallic gallium with magnetic microcapsules distributed inside; when accessing, surrounding the outer periphery of the gallium storage device with an induction coil, wherein there is a gap between the induction coil and the gallium storage device; passing a discontinuous pulsed alternating current through the induction coil to cause eddy current heating and hysteresis loss heating effects in the magnetic microcapsules in the gallium storage device, and eddy current heating effects in the solid metallic gallium, so as to heat and melt the solid metallic gallium without damaging the gallium storage device and the magnetic microcapsules.

[0022] The technical solutions provided in the embodiments of the present invention have at least some of the following beneficial effects: Because magnetic microcapsules are distributed within gallium metal, during the electromagnetic induction heating of solid gallium in a gallium storage device, eddy current heating and hysteresis loss heating effects occur within the magnetic microcapsules, dividing the overall gallium metal into multiple local sub-regions. As the magnetic microcapsules are heated, these distributed microcapsules act as dispersed heat sources, promoting heat transfer between the various internal sub-regions. Simultaneously, the solid gallium gradually transforms into liquid gallium after heating, forming a state of coexistence between solid and liquid gallium and magnetic microcapsules. The heat generated by the magnetic microcapsules is relatively less than that of the solid gallium in the same region. This method utilizes a high-efficiency microcirculation system, based on a heat gradient, to create multiple localized micro-circulations, thereby enhancing the heat transfer efficiency between the coexisting solid and liquid gallium metals. This improves the conversion efficiency of solid-to-liquid gallium metal to liquid gallium and the melting uniformity of gallium metal within the entire gallium storage device, effectively shortening the gallium melting time. Furthermore, it employs discontinuous pulsed alternating current for electromagnetic induction heating. The pulsed magnetic field is transiently strong and decays rapidly, heating only the gallium metal and the magnetic components within the magnetic microcapsules. This allows for precise control of the gallium heating temperature, preventing damage to the gallium storage device and magnetic microcapsules, and avoiding gallium contamination. While improving gallium melting efficiency, it also ensures the purity of gallium metal as much as possible. This method can solve the problems of long gallium melting times and susceptibility to contamination in related technologies. Attached Figure Description

[0023] To more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the accompanying drawings used in the embodiments will be briefly introduced below.

[0024] Figure 1 This is a flowchart illustrating the steps of a method for microcapsule-assisted electromagnetic induction heating of metallic gallium according to an embodiment of the present invention.

[0025] Figure 2 This is a schematic diagram showing the positions of an induction coil, a gallium storage device, metallic gallium, and a magnetic microcapsule in an embodiment of the present invention.

[0026] Figure 3 This is a flowchart illustrating the steps of a gallium access method according to an embodiment of the present invention.

[0027] The reference numerals in the above figures are as follows: 21. Induction coil; 22. Gallium storage device; 23. Metallic gallium; 24. Magnetic microcapsule; 25. Shell; 26. Insulation layer. Detailed Implementation

[0028] Embodiments of the present invention will now be described in more detail with reference to the accompanying drawings. It should be understood that the drawings and embodiments of the present invention are for illustrative purposes only and are not intended to limit the scope of protection of the present invention.

[0029] Because gallium readily penetrates the grain gaps of metals such as aluminum, zinc, iron, and steel, causing these metals to become brittle, crack, and pulverize, metal containers (including stainless steel) are not used to store gallium. Furthermore, gallium expands in volume upon solidification, making brittle glass bottles unsuitable. Plastic containers are typically used to hold liquid gallium, which is then cooled to a solid state for transport. However, during storage, the conventional heating method for solid gallium is baking in an oven at around 80°C. This method usually takes four to five hours to melt the gallium, and it cannot melt the gallium evenly and completely. Some of the solid gallium on the inner side may remain unmelted due to supersaturation. To melt this portion, the baking temperature may need to be increased briefly, which can cause the plastic container to deform or melt, contaminating the gallium.

[0030] In view of this, unlike the heat transfer principle from the outside to the inside based on baking in related technologies, this invention provides a method for melting gallium metal based on electromagnetic induction. By distributing magnetic microcapsules within solid gallium metal, during the electromagnetic induction heating of the solid gallium metal in the gallium storage device, the magnetic microcapsules exhibit eddy current heating and hysteresis loss heating effects, while the solid gallium metal itself also experiences eddy current heating. The magnetic microcapsules divide the overall gallium metal into multiple local sub-regions. As the magnetic microcapsules heat up, these distributed magnetic microcapsules act as dispersed heat sources, promoting heat transfer between the various internal sub-regions. Simultaneously, the solid gallium metal gradually transforms into liquid gallium metal after heating, forming a solid-liquid coexistence of gallium metal and magnetic microcapsules. In the coexisting state, the magnetic microcapsules have relatively higher heat than the solid gallium metal in the same region. Based on the heat gradient, multiple local micro-circulations are formed, which improves the heat transfer efficiency between the coexisting solid and liquid gallium metals. This, in turn, improves the conversion efficiency of solid gallium metal to liquid gallium metal and the melting uniformity of gallium metal in the entire gallium storage device, effectively shortening the melting time of gallium metal. By setting a discontinuous pulsed alternating current for electromagnetic induction heating, the pulsed magnetic field is transiently strong and decays quickly, heating only the gallium metal and the magnetic part in the magnetic microcapsules. This allows for precise control of the heating temperature of gallium metal, avoiding damage to the gallium storage device and magnetic microcapsules due to heating, and preventing contamination of gallium metal. This improves the melting efficiency of gallium metal while ensuring the purity of gallium metal as much as possible.

[0031] The following is a detailed explanation with reference to the accompanying drawings.

[0032] like Figure 1 As shown, this embodiment of the invention provides a method for microcapsule-assisted electromagnetic induction heating of metallic gallium, including steps S101 and S102.

[0033] Step S101: An induction coil is arranged around the outer periphery of the gallium storage device, wherein there is a gap between the induction coil and the gallium storage device, and magnetic microcapsules are distributed inside the solid gallium metal stored in the gallium storage device.

[0034] In step S102, a discontinuous pulsed alternating current is passed into the induction coil to cause eddy current heating and hysteresis loss heating effects in the magnetic microcapsules in the gallium storage device, as well as eddy current heating effects in the solid gallium metal, so as to heat and melt the solid gallium metal without damaging the gallium storage device and the magnetic microcapsules.

[0035] The positions of the induction coil 21, gallium storage device 22, metallic gallium 23, and magnetic microcapsule 24 can be seen in the diagram. Figure 2 As shown. In Figure 2 The diagram illustrates the gallium metal 23 inside the gallium storage device 22 and its top interface. An induction coil 21 is arranged around the outer periphery of the gallium storage device 22, with a gap between the induction coil 21 and the gallium storage device 22. When a discontinuous pulsed alternating current is applied to the induction coil 21, the solid gallium metal inside the gallium storage device 22 undergoes eddy current heating and gradually begins to melt. Simultaneously, the magnetic microcapsules also experience eddy current heating and hysteresis loss heating, acting as a heat source to conduct heat through localized circulation. This creates a solid-liquid coexistence state for the gallium metal, which then circulates heat with the magnetic microcapsules, promoting the further melting of the solid gallium metal into liquid gallium metal. During this process, the internal gallium metal gradually transfers heat to the outer wall of the gallium storage device 22. By setting the aforementioned gap, direct contact between the gallium storage device 22 and the induction coil 21 can be effectively avoided, preventing damage to the induction coil 21 and affecting subsequent electromagnetic induction heating processes. For example, for gallium storage devices with a diameter of 40mm to 500mm, a gap of 5mm to 40mm exists between the induction coil and the gallium storage device. It is understandable that the size parameters here are only examples, and in reality they can fluctuate by 10% to 20% or be adjusted according to the actual magnetic field matching.

[0036] Unlike continuous alternating current, the discontinuous pulsed alternating current in this embodiment includes a conduction period and a cutoff period within one cycle, and the duty cycle is less than 100%. In other words, the alternating current used in this embodiment is in a periodic on-off state. For example, the frequency of the alternating current in this embodiment can be a value in the range of 100Hz to 100kHz, such as 100Hz, 500Hz, 1kHz, 5kHz, 10kHz, 30kHz, 50kHz, or 100kHz, etc.

[0037] Magnetic microcapsules can be shaped like straight cylinders, rounded-head cylinders, spindles, flat ovals, or bullets, etc. Figure 2The magnetic microcapsules are used only to illustrate relative positional relationships. These microcapsules are distributed within solid-state gallium metal. In some embodiments, this distribution includes a depth-based distribution, for example, multiple magnetic microcapsules distributed at different depths within solid-state gallium metal. In other embodiments, the distribution may also include a planar coordinate-based distribution, for example, multiple magnetic microcapsules with different planar coordinates distributed at the same depth within solid-state gallium metal; or, multiple magnetic microcapsules with different planar coordinates distributed at different depths within solid-state gallium metal. That is, the differences in the distribution positions of the magnetic microcapsules within solid-state gallium metal include at least one difference in either the depth dimension or the planar coordinate dimension.

[0038] During electromagnetic induction pulse heating, both metallic gallium and magnetic microcapsules can generate heat, but the mechanisms of heat generation are different.

[0039] The mechanism of heat generation in gallium is the eddy current heating effect. When electromagnetic induction and a closed current inside a conductor generate a rapidly changing magnetic field externally, according to Faraday's law of electromagnetic induction, the magnetic flux in the closed loop changes over time, generating an induced electromotive force. Gallium itself is composed of countless natural closed conductive loops, thus spontaneously generating an induced electric field internally. Furthermore, gallium is a good conductor with many free electrons, which, driven by the induced electric field, form closed loops of current, i.e., eddy currents. Since gallium has a finite resistivity, according to Joule's law, electrical energy is converted into heat energy as the eddy currents flow within the gallium. Simultaneously, the uniform heating of the eddy currents is not limited to the surface but is distributed throughout the entire metal volume. This heating method is volumetric heating, which is more efficient than heating based on baking, where heat is transferred from the outside in.

[0040] The heating mechanism of magnetic microcapsules is based on eddy current heating and hysteresis loss heating. A discontinuous pulsed alternating current is passed through an induction coil, generating a transient alternating magnetic field. Inside the magnetic microcapsule placed in this magnetic field, eddy current and hysteresis losses occur, converting electromagnetic energy into heat energy in a very short time, achieving rapid, controllable, and localized heating. Specifically, the interior of the magnetic microcapsule uses a magnetic material, while the outer protective layer uses a material that does not contaminate gallium. Because the magnetic material has a domain structure, during the repeated rapid commutation of the pulsed magnetic field, the domains continuously flip and rub against each other. This flipping and friction consumes energy, which is converted into heat. Therefore, under the action of the induced pulsed magnetic field, the heat generated by the magnetic material has two parts: heat generated by the eddy current effect and heat generated by hysteresis. Furthermore, to prevent contamination of the gallium by the magnetic material, the magnetic microcapsule has a non-magnetic outer shell to isolate the internal magnetic material from the gallium. This will be further explained later in this embodiment.

[0041] By distributing magnetic microcapsules within solid-state gallium metal, the microcapsules divide the overall gallium metal into multiple local sub-regions. During electromagnetic induction heating, as the magnetic microcapsules heat up, these distributed microcapsules act as dispersed heat sources, promoting heat transfer between the various internal sub-regions. Simultaneously, the solid-state gallium metal gradually transforms into liquid gallium metal after heating, forming a state where solid and liquid gallium coexist with the magnetic microcapsules. The heat of the magnetic microcapsules is relatively higher than that of the solid-state gallium metal in the same region. Based on the heat gradient, multiple local micro-circulations are formed, improving the heat transfer efficiency between the coexisting solid and liquid gallium metals. This, in turn, improves the conversion efficiency of solid-state gallium metal to liquid gallium metal and the melting uniformity of gallium metal within the entire gallium storage device, effectively shortening the gallium metal melting time.

[0042] Compared to using a non-pulsed magnetic field (continuous alternating magnetic field), this embodiment uses electromagnetic induction pulses for heating, which has the advantages of extremely high temperature control accuracy and less risk of overheating. Specifically, the pulse is a cyclical process of "heating-stopping-heating-stopping...". This embodiment uses intermittent pulse heating to heat the magnetic material inside the magnetic microcapsule, achieving precise temperature control. Since the melting point of gallium is around 30°C, continuous strong heating is unnecessary. Furthermore, the pulsed magnetic field is transient and decays quickly, heating only gallium or the magnetic material without overheating, thus avoiding damage to the non-magnetic shell of the magnetic microcapsule or the gallium storage device (e.g., made of plastic). In this embodiment, by using discontinuous pulsed alternating current for electromagnetic induction heating, the pulsed magnetic field is transient and decays quickly, heating only the gallium and the magnetic part in the magnetic microcapsule. This allows for precise control of the gallium heating temperature, preventing damage to the gallium storage device and magnetic microcapsule from heating, and avoiding contamination of the gallium.

[0043] Furthermore, since gallium has a low melting point and uses electromagnetic induction for internal heating, this embodiment can achieve heating with very low power, reducing energy consumption. For example, with the duty cycle of the pulsed AC current set to 60% and the frequency set to 30kHz, a pulse power of 100W-300W can achieve synchronous heating of the magnetic microcapsules to 35℃-40℃. Combined with a PID temperature control system, the temperature control accuracy is within ±0.5℃.

[0044] In summary, this embodiment uses discontinuous pulsed alternating current to flow into the induction coil, causing eddy current heating and hysteresis loss heating effects in the magnetic microcapsules, as well as eddy current heating effects in solid gallium, thus intermittently heating the gallium. The magnetic microcapsules, acting as the internal heat source during electromagnetic induction pulse heating, can generate heat at multiple locations within the capsule. Combined with the heat generated by gallium itself due to the eddy current effect, this embodiment eliminates the need to transfer external heat during gallium heating, improving heat conversion efficiency and shortening the melting time of gallium. Since the heating temperature of gallium can be precisely controlled within a range sufficient to melt gallium without damaging the gallium storage device or the magnetic microcapsules by adjusting the frequency and on / off time of the pulsed alternating current, gallium contamination is avoided due to heating damage to the gallium storage device or magnetic microcapsules.

[0045] As an optional approach, it also includes at least one of the following: adding a plurality of magnetic microcapsules that do not contaminate gallium to a gallium storage device containing liquid gallium metal, and then cooling to form solid gallium metal with magnetic microcapsules distributed inside; or, after all the solid gallium metal in the gallium storage device has melted into liquid gallium metal, separating the magnetic microcapsules and liquid gallium metal into solid and liquid states.

[0046] The term "magnetic microcapsules are non-contaminating to gallium" means that within a preset temperature range, the magnetic microcapsules do not chemically react with gallium, do not form alloys, do not produce elemental missolution, and do not precipitate impurities. The preset temperature range includes low temperatures, room temperature, and heating conditions, such as -40℃ to 200℃.

[0047] Solid-liquid separation of magnetic microcapsules and liquid gallium can be achieved through magnetic separation or filtration separation.

[0048] Magnetic separation refers to the use of the magnetic field of an external permanent magnet / electromagnet to adsorb magnetic materials, thereby separating microcapsules from liquid gallium metal. The separation process does not contaminate the gallium metal or damage the microcapsule structure.

[0049] Filtration separation refers to the use of filter screens / membranes with pore sizes smaller than the diameter of magnetic microcapsules to filter and retain the magnetic microcapsules, thereby achieving solid-liquid separation.

[0050] As an alternative, the magnetic microcapsule comprises: a magnetic core; a non-magnetic shell located outside the magnetic core and forming a closed structure; the non-magnetic shell does not contaminate the metallic gallium within a preset temperature range; wherein, the plurality of magnetic microcapsules have density differences and distribution position differences within the liquid metallic gallium, the distribution position differences including at least one of depth dimension and planar coordinate dimension.

[0051] The non-magnetic casing does not contaminate gallium; the explanation for the non-contamination of gallium by magnetic microcapsules can be found in the documentation. Using a non-magnetic casing isolates the magnetic core from the metallic gallium, preventing contamination from impurities introduced by the magnetic core.

[0052] Multiple magnetic microcapsules with varying densities can be distributed at different locations within liquid gallium metal. The distribution of these magnetic microcapsules within the liquid gallium metal can vary; some microcapsules may be at different depths but corresponding to different planar positions, or some microcapsules may be at different depths and located at different planar positions; all of these scenarios can coexist.

[0053] Considering that gallium memory devices have a large volume (both depth and diameter), the uniformity and conduction range of heating are limited when heating large volumes of solid gallium. Some areas of solid gallium may have already melted, while other areas may require a longer time to melt due to thermal conduction. The large volume of gallium memory devices refers to both its large depth and diameter.

[0054] Therefore, by setting up magnetic microcapsules and using intermittent heating based on pulsed alternating current, large-scale heating and conduction can be transformed into heat conduction in locally segmented regions, thereby improving heat conversion efficiency, enhancing overall heating efficiency, and preventing gallium contamination. Here, large-scale heating refers to heating the entire volume of gallium, while locally segmented regions refer to multiple local sub-regions obtained by dividing the entire area containing gallium based on the distribution of magnetic microcapsules.

[0055] In some embodiments, magnetic microcapsules of different densities can be obtained by adjusting the volume ratio difference between the non-magnetic shell and the magnetic core or by selecting different materials.

[0056] In some embodiments, a first microcapsule, a second microcapsule, and a third microcapsule with different densities are prepared; wherein the density of the first microcapsule is less than the density of the liquid gallium metal, the density of the second microcapsule is equal to the density of the liquid gallium metal, and the density of the third microcapsule is greater than the density of the liquid gallium metal.

[0057] In some embodiments, the density of the magnetic microcapsules is 5.9 g / cm³. 3 -6.15g / cm 3 For example, 5.9 g / cm³ 3 6.0g / cm 3 6.1g / cm 3 or 6.15g / cm 3 etc.

[0058] In some embodiments, the diameter of the magnetic microcapsules is 0.2 mm to 0.4 mm. For example, 0.2 mm, 0.3 mm, or 0.4 mm, etc.

[0059] In some embodiments, the volume fraction of the magnetic core phase relative to the magnetic microcapsule is 74.6%-78%. For example, 74.6%, 75%, 76%, 77%, or 78%, etc.

[0060] In some embodiments, the magnetic core is selected from at least one of the following materials: Fe3O4, γ-Fe2O3, iron, cobalt, nickel, neodymium iron boron alloy, and ferrite ceramic.

[0061] Fe3O4 (Fe3O4) is a magnetic oxide with stable magnetic response. It can efficiently generate hysteresis heat and eddy current heat. Its particle size is easily controlled and it does not react with metallic gallium.

[0062] γ-Fe2O3 (γ-Fe3O4) is an oxidizing magnetic material with strong chemical stability, uniform magnetic properties, and high heat generation efficiency under pulsed magnetic field.

[0063] Iron is an elemental magnetic metal with high magnetic permeability, significant eddy current effect, fast heat generation, and moderate cost.

[0064] Cobalt is a magnetic metal with high magnetic permeability, large hysteresis loss, strong heat generation capacity, and stable chemical properties.

[0065] Nickel is a magnetic elemental metal with stable magnetic properties and good corrosion resistance. It can generate heat stably under an alternating pulsed magnetic field without contaminating gallium.

[0066] Neodymium iron boron alloy is a high-performance permanent magnet material with high magnetic energy density, extremely strong magnetic response, and outstanding heat generation efficiency, making it suitable for rapid heating scenarios.

[0067] Ferrite ceramics are sintered ferrite magnetic ceramics with excellent chemical stability, good temperature resistance, complete magnetic domain structure, and significant hysteresis heat generation effect.

[0068] In some embodiments, the non-magnetic housing is selected from at least one of the following materials: silicone rubber, perfluoroether rubber (FFKM), polytetrafluoroethylene (PTFE), alumina ceramic, zirconium oxide ceramic, boron nitride ceramic, borosilicate glass, and quartz silicon glass.

[0069] Silicone rubber is elastic, easy to mold, temperature resistant, chemically inert, completely compatible with metallic gallium, and pollution-free.

[0070] Perfluoroelastomer (FFKM) is a high-temperature resistant and highly corrosion-resistant elastic material. It is non-magnetic, chemically stable, does not react with gallium, and has excellent sealing and encapsulation effects.

[0071] Polytetrafluoroethylene (PTFE) is an inert polymer material that is non-magnetic, resistant to high and low temperatures, and non-sticky.

[0072] Alumina ceramics are inorganic non-magnetic ceramics with high hardness, excellent temperature resistance, and stable chemical properties, making them suitable as rigid coating shells.

[0073] Zirconia ceramics are high-strength non-magnetic ceramics that are temperature resistant, corrosion resistant, non-magnetic, and have a stable coating structure.

[0074] Boron nitride ceramics are insulating, non-magnetic ceramics with good thermal stability and strong chemical inertness.

[0075] High borosilicate glass is an inorganic non-magnetic glass material that is temperature resistant, corrosion resistant, transparent, and chemically stable.

[0076] Quartz silicon glass is a high-purity non-magnetic glass with excellent temperature resistance and strong chemical inertness.

[0077] For example, the non-magnetic shell is made of silicone rubber, and the magnetic core is made of neodymium iron boron alloy. The density of the silicone rubber is 1.1 g / cm³. 3 -1.2g / cm 3 Between these values, the density of neodymium iron boron alloy is approximately 7.5 g / cm³. 3 .

[0078] Microcapsules of different densities were prepared by controlling the volume ratio of silicone rubber and neodymium iron boron alloy, wherein silicone rubber was used to isolate neodymium iron boron alloy and metallic gallium.

[0079] By controlling the volume ratio of silicone rubber to NdFeB alloy, a first microcapsule with a density less than that of liquid gallium, a second microcapsule with a density equal to that of liquid gallium, and a third microcapsule with a density greater than that of liquid gallium are prepared. Specifically, the first microcapsule is prepared according to a first volume ratio of silicone rubber to NdFeB alloy; the second microcapsule is prepared according to a second volume ratio of silicone rubber to NdFeB alloy; and the third microcapsule is prepared according to a third volume ratio of silicone rubber to NdFeB alloy; wherein the first ratio is greater than the second ratio, and the second ratio is greater than the third ratio.

[0080] Furthermore, the magnetic microcapsules have a diameter of 0.2 mm to 0.4 mm, and the volume ratio of NdFeB alloy to the magnetic microcapsules is controlled between 74.6% and 78%. These magnetic microcapsules are prepared to achieve a density of 5.9 g / cm³. 3 -6.15g / cm 3 between.

[0081] As an optional solution, it further includes at least one of the following: when the pulsed alternating current has not yet been applied to the induction coil, ultrasonic treatment is performed on the solid gallium metal in the gallium storage device based on a first ultrasonic wave, and the microcrack network is generated inside the solid gallium metal using the acoustic cavitation effect; or, when the pulsed alternating current has been applied to the induction coil, ultrasonic treatment is performed on the solid gallium metal and the molten liquid gallium metal in the gallium storage device based on a second ultrasonic wave, and the solid gallium metal and the liquid gallium metal are stirred using the acoustic flow effect; wherein the sound intensity of the second ultrasonic wave is less than the sound intensity of the first ultrasonic wave.

[0082] Microcrack networks are a network structure formed by numerous fine, interconnected microcracks within solid gallium metal, created through the ultrasonic cavitation effect. These cracks are small in size, uniformly distributed, and interconnected, and do not damage the overall shape of the solid gallium metal. They serve only as an internal pretreatment method, posing no risk of fragmentation or spattering. For example, dividing the entire solid gallium metal into micro-regions with an equivalent diameter of 2mm-5mm increases the specific surface area of ​​the solid gallium. Theoretical calculations show that the specific surface area of ​​solid gallium with microcracks is increased by 15 to 25 times compared to the bulk solid gallium.

[0083] Before heating gallium metal, a microcrack network is constructed inside the solid gallium metal using a first ultrasonic wave. This expands the heated area of ​​the gallium metal, allowing the heat generated by the electromagnetic eddy current to be conducted more quickly between internal regions, thereby shortening the overall melting time. At the same time, the microcracks can release the internal stress of gallium, preventing stress concentration and local cracking caused by temperature gradients during heating, making the melting process more stable.

[0084] During the heating process, a second ultrasonic wave is used to stir the gallium metal in the solid-liquid coexistence state in situ through the acoustic flow effect. This can promote uniform heat conduction, eliminate the temperature gradient at the solid-liquid interface, improve melting uniformity and accelerate the melting rate, while preventing the gallium storage device from deforming due to local high temperature and preventing the gallium metal from being contaminated.

[0085] The first ultrasonic wave has a high sound intensity, which can ensure that the acoustic cavitation effect is fully utilized and the microcrack formation effect is better; the second ultrasonic wave has a low sound intensity, which can avoid the splashing of liquid gallium metal and damage to gallium storage devices caused by strong ultrasonic waves. The gentle stirring method does not affect the stability of electromagnetic heating, and balances melting efficiency and operational safety.

[0086] As an optional configuration, the frequencies of the first and second ultrasonic waves are 20kHz-40kHz, and the sound intensity of the first ultrasonic wave is 1.5W / cm². 2 -2.5W / cm 2 The sound intensity of the second ultrasonic wave mentioned above is 0.8 W / cm².2 -1.2W / cm 2 .

[0087] The 20kHz–40kHz frequency band is the efficient operating frequency band for ultrasonic cavitation and acoustic flow effects. Ultrasonic waves in this band can penetrate gallium storage devices without significant attenuation and stably excite the corresponding effects in solid-state gallium and liquid gallium. The frequencies of the first and second ultrasonic waves can be selected from 20kHz, 25kHz, 35kHz, 40kHz, etc., and the frequencies can be the same or different.

[0088] The first ultrasonic wave with an intensity of 1.5 W / cm²–2.5 W / cm² can effectively trigger the acoustic cavitation effect, forming a uniform microcrack network inside solid gallium metal. This achieves internal pretreatment and expands the heated area without causing solid gallium fragmentation or vibration damage to gallium storage devices due to excessively high sound intensity. The sound intensity of the first ultrasonic wave can be selected from 1.5 W / cm², 1.7 W / cm², 2.0 W / cm², 2.3 W / cm², 2.5 W / cm², etc.

[0089] A second ultrasonic wave with an intensity of 0.8 W / cm²–1.2 W / cm² can gently excite the acoustic flow effect, achieving uniform stirring of gallium in a solid-liquid coexistence state and eliminating temperature gradients. Simultaneously, it avoids high acoustic intensity-induced liquid gallium splashing and interference with the electromagnetic induction eddy current field, preventing damage to gallium storage devices and contamination of the gallium metal, thus balancing stirring effectiveness and heating stability. The acoustic intensity of the second ultrasonic wave can be selected from 0.8 W / cm², 0.9 W / cm², 1.0 W / cm², 1.1 W / cm², 1.2 W / cm², etc.

[0090] As an alternative solution, such as Figure 2 As shown, the method of surrounding the gallium storage device 22 with an induction coil 21 includes: providing a housing 25, with an insulation layer 26 disposed on the inner wall of the housing 25; disposing of the induction coil 21 inside the insulation layer 26; and placing the gallium storage device 22, which contains solid gallium metal 23 and has magnetic microcapsules 24 distributed within the solid gallium metal 23, inside the housing 25, so that the induction coil 21 surrounds the outer periphery of the gallium storage device 22.

[0091] The step of setting the induction coil 21 inside the insulation layer 26 includes: determining the specifications of the induction coil 21 based on the size characteristic parameters of the gallium storage device 22; winding the induction coil 21 inside the insulation layer 26, wherein the induction coil 21 is provided with terminals at its input and output ends for connecting to an AC power supply. Specifically, the turn spacing of the induction coil can be uniformly distributed or non-uniformly distributed.

[0092] The dimensional characteristics of the gallium storage device 22 can be selected from parameters such as radius, diameter, and outer circumference, while the specifications of the induction coil 21 can be selected from parameters such as coil diameter, number of turns, and inner diameter. The two are roughly positively correlated; the larger the dimensional characteristic parameter value of the gallium storage device 22, the larger the corresponding specification of the induction coil 21 needs to be. For example, the inner diameter of the induction coil 21 is matched to the outer diameter of the gallium storage device 22, and the inner diameter of the induction coil is 5mm to 40mm larger than the outer diameter of the gallium storage device. Furthermore, as the outer diameter of the gallium storage device increases, the corresponding spacing also increases. For example, for gallium memory devices with diameters of Φ40mm to Φ80mm, the inner diameter of the induction coil is 5mm to 10mm larger than the outer diameter of the gallium memory device; for gallium memory devices with diameters of Φ80mm to Φ300mm, the inner diameter is 10mm to 20mm larger; and for gallium memory devices with diameters of Φ300mm to Φ500mm, the inner diameter is 20mm to 40mm larger. This spacing range also avoids the problem of weak magnetic field coupling and a significant decrease in heating efficiency due to excessively large spacing. Furthermore, as the diameter of the gallium memory device increases, the number of turns in the induction coil increases accordingly to ensure appropriate inductance and magnetic field coupling strength. As the diameter of the gallium memory device increases, the diameter of the induction coil is also adaptively thickened to reduce coil resistance and minimize heat loss.

[0093] The insulation layer 26 is placed between the induction coil 21 and the housing 25 as an intermediate spacer. It can support the induction coil 21 and provide insulation for the internal gallium storage device 22, reducing the heat loss caused by the gallium transferring heat to the outside air during the heating and melting process.

[0094] Furthermore, compared to the scheme of placing the induction coil 21 on the outside of the insulation layer 26, this embodiment uses the insulation layer 26 as the intermediate spacer between the induction coil 21 and the housing 25. There is no need to add other insulating spacers between the insulation layer 26 and the housing 25, and the insulation layer 26 can directly protect the induction coil 21.

[0095] For example, the insulation layer 26 can be a ceramic fiber felt insulation layer with a thickness of 100mm-200mm, which has low thermal conductivity, high temperature resistance and excellent thermal insulation performance. The shell material can be metal, which can shield the electromagnetic field interference to other electronic products in the surrounding area during electromagnetic induction heating.

[0096] As an alternative approach, passing a discontinuous pulsed alternating current into the induction coil includes: determining the current frequency range of the pulsed alternating current output based on the size characteristic parameters of the gallium storage device; and controllably passing the pulsed alternating current within the current frequency range into the induction coil.

[0097] The dimensional characteristics of gallium memory devices can include radius, diameter, circumference, etc.

[0098] The formula for the skin depth of eddy current heating is as follows: (1) In the formula, Indicates skin depth. Indicates the resistivity of the material. Indicates the current frequency. It represents the magnetic permeability.

[0099] Since gallium is a non-magnetic metal, its permeability is approximately equal to that of vacuum, and the resistivity of solid gallium and liquid gallium each has a fixed value, i.e. , , Since both are fixed, the skin depth for gallium eddy current heating is negatively correlated with the current frequency; the higher the current frequency, the smaller the skin depth.

[0100] Considering that the smaller the skin depth, the more concentrated the eddy currents are on the material surface, a larger dimensional characteristic parameter value corresponds to a smaller current frequency range, in order to allow the eddy currents to penetrate deeper and the heating to be more uniform. Therefore, taking a large-diameter gallium memory device as an example, a relatively small current frequency is required.

[0101] As an alternative, the method further includes: detecting the temperature of the outer wall of the gallium memory device to regulate the discontinuous pulsed alternating current.

[0102] Specifically, temperature sensing components are typically made of metal. For example, inserting a thermocouple into a gallium storage device to monitor temperature would cause gallium contamination and probe corrosion. Customizing the thermocouple would incur additional costs, and ensuring the gaseous integrity of the gallium storage device requires an additional sealing structure, further increasing the overall investment beyond the thermocouple customization cost. This invention, by detecting the outer wall temperature of the gallium storage device, avoids contamination and adverse effects during gallium melting, while eliminating the cost of the necessary sealing structure.

[0103] When the outer wall temperature is less than a preset temperature threshold, the output power of the pulsed AC current is adjusted according to the temperature difference between the outer wall temperature and the preset temperature threshold to control the heating temperature of the gallium metal within a preset temperature range. The preset temperature range corresponds to a temperature higher than the melting temperature of the gallium metal and lower than the smaller of the destruction temperature of the gallium storage device and the destruction temperature of the magnetic microcapsule. The preset temperature threshold is the upper limit of the heating temperature of the gallium metal obtained by calculating the heat conduction of the gallium storage device.

[0104] Specifically, the smaller the temperature difference between the outer wall temperature and the preset temperature threshold, the lower the output power of the pulsed AC current. Adjusting the output power of the pulsed AC current based on the temperature difference is to control the heating temperature of the gallium metal within the preset temperature range, preventing damage to the gallium storage device and magnetic microcapsules while heating and melting the gallium. Damage to the gallium storage device and magnetic microcapsules is a broad term, including deformation, partial melting, and complete melting. For example, the preset temperature range corresponding to the heating temperature of the gallium metal is, for instance, 40℃-80℃. The upper limit of the heating temperature of the gallium metal, obtained after heat conduction calculations for the gallium storage device, is a parameter value within the closed range of 40℃-50℃. That is, the preset temperature threshold corresponding to the detected outer wall temperature is 40℃-50℃. For example, it can be set to 40℃, 45℃, 48℃, or 50℃, etc. This method utilizes external wall temperature detection to regulate the internal gallium heating temperature of a gallium storage device. It considers the difference in thermal conductivity between the gallium inside the device and the external wall, achieving a relatively reliable, non-contaminating, and cost-effective heating scheme. This ensures precise control of the internal gallium heating temperature by adjusting the parameters of the intermediate frequency AC current based on external wall temperature measurements. This allows the solid gallium inside the storage device to completely melt into liquid gallium, without contaminating the gallium from the magnetic microcapsules themselves, thus meeting the requirements for gallium extraction. Simultaneously, the heat generated by the eddy current effect of the gallium is transferred to the external wall of the storage device, preventing the temperature rise of the external wall from becoming excessively high, remaining well below the melting and deformation temperature of the external wall, thus ensuring that the gallium is not contaminated.

[0105] When determining the preset temperature threshold, the thermal conductivity and wall thickness of the gallium storage device can be used as parameters. The safe heating temperature inside the gallium metal within the preset temperature range can be converted into the upper limit of the outer wall temperature of the gallium storage device through the heat conduction formula.

[0106] If the outer wall temperature reaches a preset temperature threshold or the coil energization time exceeds a set time, the pulsed AC current will be stopped from being supplied to the induction coil.

[0107] Whether power is cut off when the outer wall temperature reaches a preset temperature threshold or when the cumulative energization time of the coil exceeds a set time, this helps to prevent damage to the gallium storage device and the magnetic microcapsule. Because the magnetic microcapsule, in conjunction with electromagnetic induction heating, has high thermal efficiency, the melting time of metallic gallium is relatively short. The aforementioned set time can be 10-25 minutes, or the next set time can be set based on the average melting time of multiple historical heating processes.

[0108] As an optional approach, it also includes: performing in-situ ultrasonic testing on the gallium metal in the gallium storage device to determine the current state of the gallium metal.

[0109] For example, ultrasonic testing can be performed when the outer wall temperature reaches a preset temperature threshold or when the coil is energized for a cumulative duration exceeding a set time; ultrasonic testing can also be performed during heating to determine at a certain moment whether the gallium has completely melted or partially melted after heating.

[0110] Next, with the gallium metal currently in a solid-liquid coexistence state, the gallium storage device is removed and the liquid gallium metal is poured out. The gallium storage device is then returned to its original position, and the pulsed AC current is continued to be applied to the induction coil to further heat the remaining solid gallium metal in the storage device. Pouring out the liquid gallium metal before heating the remaining solid gallium metal allows for the use of the liquid gallium metal first, meeting practical application needs. Furthermore, after the liquid gallium metal is poured out, the remaining solid gallium metal melts more quickly, helping to reduce the overall heating time.

[0111] Alternatively, if the gallium metal is currently in a solid-liquid coexistence state, the aforementioned pulsed alternating current can be continuously applied to the aforementioned induction coil to continue heating the remaining solid gallium metal in the solid-liquid coexistence state within the gallium storage device. Continuously heating the remaining solid gallium metal eliminates the need for repeated disassembly and reassembly, simplifying the operation process and preventing unmelted gallium metal from coming into contact with the outside environment and becoming contaminated.

[0112] Because liquid gallium is not attracted by magnetic materials, and the magnetic field generated by the magnetic material in the microcapsule is not regularly distributed, multiple microcapsules will not be adsorbed together under the action of viscous resistance of liquid metal. Even if some are adsorbed or close together, it will not affect the subsequent magnetic field heating.

[0113] Next, while the gallium metal is currently in a liquid state, the gallium storage device is removed and the liquid gallium metal is poured out of the gallium storage device.

[0114] The gallium in the gallium storage device is entirely in a liquid state, indicating that the melting target has been fully achieved, and the liquid gallium can be extracted for subsequent use. Compared to extracting liquid gallium from a solid-liquid coexistence state, extracting gallium after complete liquefaction is not only more efficient, but also results in more consistent quality of the extracted liquid gallium.

[0115] As an optional approach, in-situ ultrasonic testing is performed on the gallium metal in the aforementioned gallium memory device to determine its current state. This includes: with an induction coil surrounding the gallium memory device, transmitting a sound at a frequency of 1MHz to 4MHz and an intensity of 5mW / cm into the gallium memory device. 2 -30mW / cm 2 The third ultrasonic wave is received; the reflected echo of the third ultrasonic wave is received; and the current state of gallium is determined based on the changes in the echo characteristics of the reflected echo.

[0116] The ultrasonic testing frequency must simultaneously meet four requirements: solid gallium penetration, liquid gallium attenuation suppression, solid-liquid interface reflection, and prevention of resonance damage to the outer shell of the magnetic microcapsule, which could lead to leakage of internal magnetic materials. Therefore, the frequency of the third ultrasonic wave was set to 1MHz~4MHz with a sound intensity of 5mW / cm². 2 -30mW / cm 2 (Corresponding to milliwatt-level power), it achieves excellent interface resolution, accurately determining whether gallium is in a solid, liquid, or solid-liquid coexistence state, and clearly identifying the corresponding solid-liquid interface, thus improving the detection accuracy of the solid-liquid interface. Simultaneously, it avoids significant thermal interference or cavitation effect interference to the phase transition state of gallium, and causes no damage to magnetic microcapsules, achieving stable detection of the solid-liquid interface position. The frequency of the third ultrasonic wave can be selected from 1MHz, 1.5MHz, 2MHz, 2.5MHz, 3MHz, 3.5MHz, 4MHz, etc. The sound intensity of the third ultrasonic wave can be 5mW / cm², 10mW / cm², 20mW / cm², 25mW / cm², 30mW / cm².

[0117] Specifically, solid-state gallium and liquid-state gallium exhibit significant differences in acoustic impedance, forming a clear solid-liquid interface. When ultrasonic waves are incident on this interface, they undergo strong reflection, generating a characteristic echo. If gallium is completely melted into a liquid state, without a solid-liquid interface, this characteristic reflected echo will not occur. Furthermore, ultrasonic waves propagate faster in solid-state gallium than in liquid-state gallium, resulting in significant differences in echo time and waveform characteristics. Therefore, using ultrasonic detection to determine the state of gallium within a gallium storage device offers high detection accuracy.

[0118] In other words, compared to manually observing the state of gallium metal, the in-situ ultrasonic detection method used in this embodiment can improve detection efficiency while ensuring higher detection accuracy. Moreover, this detection method does not require opening the cover or removing the gallium storage device, which can avoid the introduction of external impurities and contamination from contact between the gallium metal and the air. It also saves the time cost required to remove the gallium storage device to determine the melting state of the gallium metal (if it is not completely melted) and then put it back in place, while waiting for the appropriate heating parameters (the parameters of the induction coil need to be adjusted).

[0119] like Figure 3 As shown, this embodiment of the invention also provides a method for accessing gallium metal, including steps S301 to S303.

[0120] Step S301: Add multiple magnetic microcapsules that do not contaminate gallium to a gallium storage device containing liquid gallium metal, and then cool it to form solid gallium metal with magnetic microcapsules distributed inside.

[0121] In step S302, when the device is used, an induction coil is arranged around the outer periphery of the gallium storage device, wherein there is a gap between the induction coil and the gallium storage device.

[0122] In step S303, a discontinuous pulsed alternating current is passed into the induction coil to cause eddy current heating and hysteresis loss heating effects in the magnetic microcapsules in the gallium storage device, as well as eddy current heating effects in the solid gallium metal, so as to heat and melt the solid gallium metal without damaging the gallium storage device and the magnetic microcapsules.

[0123] Based on the method provided in this embodiment, a gallium storage device for storing and / or transporting gallium metal can directly participate in the heating and melting process of gallium metal. There is no need to transfer or open the gallium storage device before heating, which reduces contact between the gallium metal and the external environment, lowering the risk of gallium contamination. Passing a discontinuous pulsed alternating current into the induction coil causes the gallium metal itself to generate heat, as well as the magnetic microcapsules distributed inside the gallium metal, shortening the melting time. Combined with the spacing between the induction coil and the gallium storage device, and the parameter control of the pulsed alternating current, it is possible to avoid damage to the gallium storage device and magnetic microcapsules due to heating, and to prevent contamination of the gallium metal, thereby improving the melting efficiency of gallium metal while ensuring the purity of the gallium metal as much as possible.

[0124] It should be noted that the term "comprising" and its variations used in the embodiments of the present invention are open-ended, meaning "including but not limited to". The terms "first", "second", etc., are used for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of indicated technical features.

[0125] The appearance of the term "embodiment" in various places in this specification does not necessarily mean the same embodiment, nor does it imply that it is independent of or alternative to other embodiments. The various embodiments in this specification are described in a related manner, and the same or similar parts between the various embodiments can be referred to each other.

Claims

1. A method for synergistic electromagnetic induction heating of metallic gallium using microcapsules, characterized in that, include: An induction coil is arranged around the outer periphery of a gallium storage device, wherein there is a gap between the induction coil and the gallium storage device, and magnetic microcapsules are distributed inside the solid gallium metal stored in the gallium storage device. A discontinuous pulsed alternating current is passed into the induction coil to induce eddy current heating and hysteresis loss heating effects in the magnetic microcapsules within the gallium storage device, as well as eddy current heating effects in the solid gallium metal, thereby heating and melting the solid gallium metal without damaging the gallium storage device and the magnetic microcapsules.

2. The method according to claim 1, characterized in that, It also includes at least one of the following: Multiple magnetic microcapsules that do not contaminate gallium are added to a gallium storage device containing liquid gallium metal, followed by cooling to form solid gallium metal with magnetic microcapsules distributed inside; or, After all the solid gallium metal in the gallium storage device is melted into liquid gallium metal, the magnetic microcapsules and the liquid gallium metal are separated into solid and liquid states.

3. The method according to claim 2, characterized in that, The magnetic microcapsules include: Magnetic nucleus; A non-magnetic shell is located outside the magnetic core and is a closed structure; within a preset temperature range, the non-magnetic shell does not contaminate the metallic gallium. Among them, multiple magnetic microcapsules have density differences and distribution position differences within liquid gallium metal, and the distribution position differences include at least one of depth dimension and planar coordinate dimension; Optionally, magnetic microcapsules of different densities can be obtained by adjusting the volume ratio difference between the non-magnetic shell and the magnetic core or by selecting different materials. Optionally, a first microcapsule, a second microcapsule, and a third microcapsule with different densities are prepared; wherein the density of the first microcapsule is less than the density of the liquid gallium metal, the density of the second microcapsule is equal to the density of the liquid gallium metal, and the density of the third microcapsule is greater than the density of the liquid gallium metal. Optionally, the magnetic microcapsules have a density of 5.9 g / cm³. 3 -6.15g / cm 3 ; Optionally, the diameter of the magnetic microcapsules is 0.2 mm to 0.4 mm; Optionally, the volume ratio of the magnetic core to the magnetic microcapsule is 74.6%-78%. Optionally, the magnetic core is selected from at least one of the following materials: Fe3O4, γ-Fe2O3, iron, cobalt, nickel, neodymium iron boron alloy, ferrite ceramic; Optionally, the non-magnetic shell is made of at least one of the following materials: silicone rubber, perfluoroether rubber (FFKM), polytetrafluoroethylene (PTFE), alumina ceramic, zirconium oxide ceramic, boron nitride ceramic, borosilicate glass, or quartz silicon glass.

4. The method according to claim 1, characterized in that, It also includes at least one of the following: Before the pulsed alternating current is applied to the induction coil, the solid gallium metal inside the gallium storage device is ultrasonically treated based on the first ultrasonic wave, and the acoustic cavitation effect is used to generate a microcrack network inside the solid gallium metal; or... With the pulsed alternating current already applied to the induction coil, the solid gallium metal and the molten liquid gallium metal in the gallium storage device are ultrasonically treated based on the second ultrasonic wave, and the solid gallium metal and the liquid gallium metal are stirred by the acoustic flow effect. The intensity of the second ultrasonic wave is less than that of the first ultrasonic wave.

5. The method according to claim 4, characterized in that, The frequencies of the first and second ultrasonic waves are 20kHz-40kHz, and the sound intensity of the first ultrasonic wave is 1.5W / cm². 2 -2.5W / cm 2 The sound intensity of the second ultrasonic wave is 0.8 W / cm². 2 -1.2W / cm 2 .

6. The method according to any one of claims 1-5, characterized in that, The induction coil is arranged around the outer periphery of the gallium memory device, including: A housing is provided, wherein the inner wall of the housing is provided with a heat insulation layer; An induction coil is installed inside the insulation layer; A gallium storage device containing solid gallium metal with magnetic microcapsules distributed within it is placed inside the housing, such that the induction coil is arranged around the outer periphery of the gallium storage device.

7. The method according to any one of claims 1-5, characterized in that, Also includes: Detect the temperature of the outer wall of the gallium storage device; When the outer wall temperature is lower than a preset temperature threshold, the output power of the pulsed alternating current is adjusted according to the temperature difference between the outer wall temperature and the preset temperature threshold to control the heating temperature of the gallium metal within a preset temperature range. The preset temperature range corresponds to a temperature higher than the melting temperature of gallium metal and lower than the smaller of the destruction temperature of the gallium storage device and the destruction temperature of the magnetic microcapsule. The preset temperature threshold is the upper limit of the heating temperature of the gallium metal obtained by calculating the thermal conductivity of the gallium storage device. If the outer wall temperature reaches a preset temperature threshold or the cumulative energization time of the coil exceeds a set time, the pulsed AC current will be stopped from being supplied to the induction coil.

8. The method according to claim 7, characterized in that, Also includes: In-situ ultrasonic testing is performed on the gallium metal in the gallium storage device to determine the current state of the gallium metal; If the gallium metal is currently in a solid-liquid coexistence state, remove the gallium storage device and pour out the liquid gallium metal. Then, return the gallium storage device to its original position and continue to supply the pulsed AC current to the induction coil to continue heating the remaining solid gallium metal in the gallium storage device. Alternatively, if the gallium metal is currently in a solid-liquid coexistence state, continue to supply the pulsed AC current to the induction coil to continue heating the remaining solid gallium metal in the gallium storage device in the solid-liquid coexistence state. With gallium metal in a liquid state, the gallium storage device is removed and the liquid gallium metal is poured out of the gallium storage device.

9. The method according to claim 8, characterized in that, Perform in-situ ultrasonic testing on the gallium metal in the gallium storage device to determine the current state of the gallium metal, including: With the induction coil surrounding the gallium storage device, a sound emission with a frequency of 1MHz to 4MHz and an intensity of 5mW / cm is emitted into the gallium storage device. 2 -30mW / cm 2 The third ultrasound; Receive the reflected echo of the third ultrasonic wave; The current state of gallium is determined based on the changes in the echo characteristics of the reflected echo.

10. A method for accessing gallium metal, characterized in that, include: Multiple magnetic microcapsules that do not contaminate gallium are added into a gallium storage device containing liquid gallium metal, and then the device is cooled to form solid gallium metal with magnetic microcapsules distributed inside. When in use, an induction coil is arranged around the outer periphery of the gallium storage device, wherein there is a gap between the induction coil and the gallium storage device; A discontinuous pulsed alternating current is passed into the induction coil to induce eddy current heating and hysteresis loss heating effects in the magnetic microcapsules within the gallium storage device, as well as eddy current heating effects in the solid gallium metal, thereby heating and melting the solid gallium metal without damaging the gallium storage device and the magnetic microcapsules.

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