Apparatus and method for preparing flux for aluminum and aluminum alloy

Abstract

This invention provides an apparatus and method for preparing flux for aluminum and aluminum alloys. It includes a furnace body, a furnace cover, a sealing ring, a heating element, a vent pipe, and a seal failure detection device. The furnace body has a accommodating space and an opening. The furnace cover is detachably installed at the opening of the furnace body. The sealing ring is annular and positioned between the furnace body and the furnace cover. The heating element is located inside the furnace body for heating the raw materials inside. The vent pipe is located at the top of the furnace body and communicates with the interior of the furnace body. The seal failure detection device is located on the outside of the sealing ring to provide an alert after seal failure. The apparatus and method for preparing flux for aluminum and aluminum alloys provided by this invention improve the effectiveness of the flux and extend the service life of the equipment.

Description

Technical Field

[0001] This invention relates to the field of aluminum alloy purification flux technology, and in particular to a preparation apparatus and method for a flux for aluminum and aluminum alloys. Background Technology

[0002] Currently, during the smelting process of aluminum and aluminum alloys, the molten aluminum and aluminum alloys readily react with moisture in the air, producing impurities such as hydrogen and oxides, which greatly affect the quality of aluminum products. Therefore, fluxes are used in the aluminum and aluminum alloy smelting and casting process for refining to remove impurities such as hydrogen, oxides, and alkali metals.

[0003] However, the flux used in the remelting of aluminum and aluminum alloys generates magnesium oxide and hydrochloric acid corrosive gases during the preparation process, which corrode the reaction equipment. Moreover, the magnesium chloride component in the flux easily reacts with water in the air to form crystalline hydrates. These crystalline hydrates not only greatly affect the performance of the flux used in aluminum and aluminum alloys but also reduce the service life of the equipment. Summary of the Invention

[0004] The purpose of this invention is to provide an apparatus and method for preparing flux for aluminum and aluminum alloys, so as to at least solve the technical problem in the prior art that the flux is prone to corrosion reaction with the equipment during the preparation process, so as to improve the use effect of the flux and the service life of the equipment.

[0005] Specifically, the present invention provides an apparatus for preparing flux for aluminum and aluminum alloys, characterized in that it comprises:

[0006] The furnace body has a receiving space inside and an opening is provided on the furnace body;

[0007] A furnace cover, which is detachably installed at the opening of the furnace body;

[0008] A sealing ring, wherein the sealing ring is annular and is disposed between the furnace body and the furnace cover;

[0009] A heating element is disposed inside the furnace body and is used to heat the raw materials inside the furnace body;

[0010] A vent pipe is provided at the top of the furnace body and is connected to the interior of the furnace body;

[0011] A seal failure detection device is disposed on the outside of the sealing ring to provide a warning after the sealing ring fails.

[0012] Optionally, the seal failure detection device includes:

[0013] Multiple shape memory alloys are disposed on the outside of the sealing ring so that the shape memory alloys deform when heat leakage occurs due to failure at the corresponding position of the sealing ring.

[0014] Multiple electronic tags and an electronic tag reader are provided. The electronic tags are disposed on the inside of the shape memory alloy so that the electronic tags are hidden from being read by the electronic tag reader, and the electronic tags are exposed from the inside of the shape memory alloy when the shape memory alloy is deformed, and then read by the electronic tag reader.

[0015] Optionally, the preparation apparatus further includes:

[0016] A phase change material is disposed between the sealing ring and the shape memory alloy, and the phase change material is thermally connected to the shape memory alloy.

[0017] Optionally, the outer peripheral surface of the sealing ring is provided with a process groove that penetrates the top surface of the sealing ring, the process groove does not penetrate the bottom surface of the sealing ring, and the process groove does not penetrate the inner surface of the sealing ring.

[0018] The preparation apparatus further includes a heat-conducting strip disposed within the process tank, which is thermally connected to the phase change material.

[0019] Optionally, a filter screen is provided at the vent pipe, and the vent pipe is configured to: evacuate the furnace body before the heating step, and discharge the hydrochloric acid gas inside the furnace body during the heating step;

[0020] Optionally, a first hygrometer is installed on the top of the furnace body and / or the furnace cover, and a second hygrometer is installed on the vent pipe.

[0021] Optionally, the preparation apparatus further includes:

[0022] A cooling ring is fixed at the opening of the furnace body. The cooling ring has an annular groove. A sealing ring closes the upper opening of the annular groove or is inserted into the annular groove. The sealing ring and the bottom surface of the annular groove define an annular cooling cavity. The cooling ring is provided with a water inlet and a water outlet, which are connected to the annular cooling cavity.

[0023] Optionally, the preparation process of the flux for aluminum and aluminum alloys uses the preparation apparatus as described in any one of the claims, and the preparation method includes:

[0024] Pretreatment step: After drying the raw materials, add them to the furnace body and mix them evenly;

[0025] Vacuuming step: Seal the furnace cover onto the furnace body, connect the vent pipe to the vacuum pump, and perform vacuuming on the furnace body;

[0026] Heating step: The raw material in the furnace is heated by the heating element, and the hydrochloric acid gas in the furnace is discharged through the vent pipe to obtain liquid flux;

[0027] Crushing step: In response to the end of the heating step, after the liquid flux solidifies into solid flux, the solid flux is crushed to obtain the flux product, wherein the particle size of the flux product is 2-5 mm and the magnesium oxide content in the flux product is less than 0.5%.

[0028] Optionally, the raw material comprises, by mass percentage: NaCl: 39-61%, MgCl2: 39-61%;

[0029] In the heating step, the heating temperature is 600-700℃.

[0030] Optionally, the vacuuming step further includes:

[0031] Circulating coolant is injected into the cooling ring, and the humidity at the top of the furnace measured by the first hygrometer and the humidity of the exhaust gas measured by the second hygrometer are obtained simultaneously; wherein, the temperature of the coolant is cooling water at 10-20°C.

[0032] In the apparatus for preparing flux for aluminum and aluminum alloys of the present invention, air is extracted from the furnace body through a vent pipe during the preparation of the flux. The vacuum environment inside the furnace effectively reduces the corrosive hydrochloric acid gas generated during the reaction, preventing damage to the furnace body and thus extending its service life. Furthermore, the flux prepared using the apparatus of the present invention has a low magnesium oxide content, significantly improving the quality of the finished flux and ensuring the refining effect of aluminum and aluminum alloys.

[0033] Furthermore, when the sealing ring fails, the sealing failure detection device will issue a warning, which can detect the vacuum furnace sealing failure during the reaction process, preventing it from affecting the quality of the flux used for aluminum and aluminum alloys and preventing damage to the vacuum furnace.

[0034] The above and other objects, advantages and features of the present invention will become more apparent to those skilled in the art from the following detailed description of specific embodiments of the invention in conjunction with the accompanying drawings. Attached Figure Description

[0035] The following sections will describe some specific embodiments of the invention in detail by way of example and not limitation, with reference to the accompanying drawings. The same reference numerals in the drawings denote the same or similar parts or portions. Those skilled in the art should understand that these drawings are not necessarily drawn to scale. In the drawings:

[0036] Figure 1This is a schematic structural diagram of an apparatus for preparing flux for aluminum and aluminum alloys according to an embodiment of the present invention;

[0037] Figure 2 This is a schematic structural diagram of the cover and furnace body seal of an apparatus for preparing flux for aluminum and aluminum alloys according to an embodiment of the present invention;

[0038] Figure 3 yes Figure 2 A schematic partial structural diagram at point A in the middle;

[0039] Figure 4 This is a schematic structural diagram of the assembly of a sealing ring and a phase change material in an apparatus for preparing flux for aluminum and aluminum alloys according to an embodiment of the present invention.

[0040] Figure 5 yes Figure 4 Cross-sectional view at point BB;

[0041] Figure 6 This is a schematic structural diagram of a shape memory alloy and an electronic tag in a flux preparation apparatus for aluminum and aluminum alloys according to an embodiment of the present invention.

[0042] Figure 7 This is a schematic structural diagram of a shape memory alloy and an electronic tag in a flux preparation apparatus for aluminum and aluminum alloys according to an embodiment of the present invention, when the seal fails.

[0043] Figure 8 This is a flowchart of a method for preparing flux for aluminum and aluminum alloys according to an embodiment of the present invention. Detailed Implementation

[0044] The following reference Figures 1 to 8 This invention describes an apparatus and method for preparing flux for aluminum and aluminum alloys according to embodiments of the present invention. The terms "front," "rear," "upper," "lower," "top," "bottom," "inner," "outer," and "lateral," etc., indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings. They are used solely for the purpose of facilitating and simplifying the description of the invention, and do not indicate or imply that the apparatus or component referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention.

[0045] The terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first," "second," etc., may explicitly or implicitly include at least one of that feature, that is, include one or more of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified. When a feature "includes or contains" one or more of the features it encompasses, unless otherwise specifically stated, this indicates that other features are not excluded and may be further included.

[0046] Unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," "fixing," and "coupling," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art should be able to understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0047] In the description of this embodiment, the terms "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0048] Figure 1 This is a schematic structural diagram of a corrosion-resistant vacuum reactor apparatus for remelting flux according to an embodiment of the present invention, as shown below. Figure 1 As shown, and refer to Figures 2 to 8 This invention provides an apparatus for preparing flux for aluminum and aluminum alloys, comprising: a furnace body 10, a furnace cover 20, a sealing ring 30, a heating element, a vent pipe 80, and a seal failure detection device. The furnace body 10 has a accommodating space and an opening. The furnace cover 20 is detachably installed at the opening of the furnace body 10. The sealing ring 30 is annular and is disposed between the furnace body 10 and the furnace cover 20. The heating element is disposed inside the furnace body 10 for heating the raw materials inside the furnace body 10. The vent pipe 80 is disposed at the top of the furnace body 10 and communicates with the interior of the furnace body 10. The seal failure detection device is disposed on the outside of the sealing ring 30 to provide a warning after the sealing ring fails.

[0049] In this embodiment, during use, the furnace cover 20 is first opened, and the raw material is added into the furnace body 10 through the opening. Then, the furnace cover 20 is placed over the opening of the furnace body 10 to seal it. Next, the air inside the furnace body 10 is extracted through the vent pipe 80 to create a vacuum environment. Then, the raw material inside the furnace body 10 is heated by the heating element. The raw material reacts in a vacuum environment, effectively preventing the magnesium chloride in the raw material from reacting with moisture in the air. This results in less magnesium oxide and hydrochloric acid corrosion gas generated during the preparation process, thus reducing the magnesium oxide content in the finished flux. When using the preparation apparatus of this invention to prepare flux for aluminum and aluminum alloys, damage to the furnace body 10 from hydrochloric acid corrosion gas can be effectively prevented, thereby extending the service life of the furnace body 10. Furthermore, the flux prepared using the preparation apparatus of this invention has a lower magnesium oxide content, significantly improving the quality of the finished flux and ensuring the refining effect of aluminum and aluminum alloys.

[0050] Furthermore, when the sealing ring 30 fails, the sealing failure detection device will issue a warning, which can detect the vacuum furnace sealing failure during the reaction process, preventing it from affecting the quality of the flux used for aluminum and aluminum alloys and preventing damage to the vacuum furnace.

[0051] In some embodiments of the present invention, such as Figure 6 and Figure 7 As shown, the seal failure detection device includes multiple shape memory alloys 40, multiple electronic tags 50, and an electronic tag reader. The shape memory alloys 40 are positioned on the outside of the sealing ring 30 so that they deform when heat leakage occurs due to failure at the corresponding position of the sealing ring 30. The electronic tags 50 are positioned on the inside of the shape memory alloys 40, so that they are hidden from being read by the electronic tag reader, and that they are exposed from the inside of the shape memory alloys 40 when they deform, and are then read by the electronic tag reader.

[0052] In this embodiment, a shape memory alloy 40 is placed outside the sealing ring 30, and an electronic tag 50 is attached to the inside of the shape memory alloy 40 to block the signal transmission of the electronic tag 50 and its reader. When the seal fails, the vacuum furnace dissipates heat to the outside through the location of the seal failure. The increased outside temperature causes the shape memory alloy 40 to deform, exposing the electronic tag 50 on the inside of the shape memory alloy 40. The electronic tag 50 is then read by the electronic tag reader, allowing the vacuum furnace seal failure to be detected during the reaction process. This prevents the quality of the flux used for aluminum and aluminum alloys from being affected and prevents damage to the vacuum furnace.

[0053] In some embodiments of the present invention, such as Figures 3 to 5 As shown, the preparation apparatus also includes a phase change material 60. The phase change material 60 is disposed between the sealing ring 30 and the shape memory alloy 40, and the phase change material 60 is thermally connected to the shape memory alloy 40.

[0054] When the sealing ring 30 fails and heat leakage occurs, the leaked heat is directly conducted to the shape memory alloy 40, which could burn out the electronic tag 50 attached to the shape memory alloy 40. The phase change material 60, after storing the leaked heat, will not overheat; that is, the temperature of the phase change material 60 will not become too high. In this embodiment, a phase change material 60 is added to both the sealing ring 30 and the shape memory alloy 40. The leaked heat is stored in the phase change material 60, which heats the shape memory alloy 40, causing it to deform, without burning out the electronic tag 50, thus protecting the electronic tag 50.

[0055] In some embodiments of the present invention, such as Figure 3 As shown, a process groove 31 is provided on the outer peripheral surface of the sealing ring 30, penetrating the top surface of the sealing ring 30. The process groove 31 does not penetrate the bottom surface of the sealing ring 30, nor does it penetrate the inner surface of the sealing ring 30. The preparation apparatus also includes a heat-conducting strip, which is disposed in the process groove 31 and thermally connected to the phase change material 60.

[0056] In this embodiment, when the sealing ring 30 fails, heat is quickly transferred to the phase change material 60 via the heat conduction strip, and then the phase change material 60 heats the shape memory alloy 40, causing the shape memory alloy 40 to deform and the electronic tag 50 on the inner side of the shape memory alloy 40 to be exposed. The electronic tag reader reads the electronic tag 50, thereby detecting the failure of the vacuum furnace seal and preventing it from affecting the quality of the flux used for aluminum and aluminum alloys.

[0057] In some embodiments of the present invention, a filter screen is provided at the vent pipe 80, and the vent pipe 80 is configured to: evacuate the furnace body 10 before the heating step, and discharge the hydrochloric acid gas inside the furnace body 10 during the heating step.

[0058] Specifically, the filter screen separates the raw materials from the gas, which is air and / or hydrochloric acid gas. During the heating process, the hydrochloric acid gas inside the furnace body 10 is discharged through the vent pipe 80, which can prevent damage to the furnace body 10 caused by the corrosive hydrochloric acid gas.

[0059] In some embodiments of the present invention, a first hygrometer is installed on the top of the furnace body 10 and / or the furnace cover 20, and a second hygrometer is installed on the vent pipe 80. If the operating power of the vacuum pump is too high, the airflow will accumulate in the inlet area of ​​the vent pipe 80, that is, the airflow will accumulate in the upper part of the furnace body 10. Since the temperature at the top of the furnace body 10 and the furnace cover 20 is relatively lower than the temperature at the bottom of the furnace body 10, the airflow accumulating at the above-mentioned locations will easily generate condensate. After a large amount of condensate accumulates, it will fall into the bottom of the furnace body 10. This water will react with the raw materials, thereby affecting the quality of the flux product.

[0060] In this embodiment, a first hygrometer is used to detect the humidity above the interior of the furnace body 10, which is recorded as the furnace top humidity; a second hygrometer is used to detect the humidity inside the ventilation duct, which is recorded as the extraction humidity. During use, the operating power of the vacuum pump can be controlled based on the aforementioned furnace top humidity and extraction humidity, thereby preventing airflow from accumulating in the inlet area of ​​the ventilation duct 80.

[0061] In some embodiments of the present invention, such as Figure 1 and Figure 2 As shown, the preparation apparatus also includes a cooling ring 90, which is fixed at the opening of the furnace body 10. The cooling ring 90 has an annular groove, and a sealing ring 30 closes the upper opening of the annular groove or is inserted into the annular groove. The sealing ring 30 and the bottom surface of the annular groove define an annular cooling cavity 91. The cooling ring 90 is provided with a water inlet and a water outlet, which are connected to the annular cooling cavity 91.

[0062] In this embodiment, by setting a cooling ring 90, cooling water can be circulated in the annular cooling cavity 91 of the cooling ring 90 to cool the sealing ring 30, thereby improving the service life of the sealing ring 30 and preventing the sealing ring 30 from deforming due to being in a high-temperature environment during use, which would affect its sealing effect.

[0063] In some embodiments of the present invention, such as Figure 8 As shown, the preparation apparatus of any of the above embodiments is used in the preparation process of flux for aluminum and aluminum alloys, and the preparation method includes:

[0064] Pretreatment steps: After drying the raw materials, add them to the furnace body 10 and mix them evenly.

[0065] Vacuuming procedure: Seal the furnace cover 20 onto the furnace body 10, connect the vent pipe 80 to the vacuum pump, and perform vacuuming on the furnace body 10.

[0066] Heating step: The raw material inside the furnace body 10 is heated by the heating element, and the hydrochloric acid gas inside the furnace body 10 is discharged through the vent pipe 80 to obtain liquid flux.

[0067] Crushing step: In response to the end of the heating step, after the liquid flux has solidified into solid flux, the solid flux is crushed to obtain the finished flux product.

[0068] In this embodiment, drying the raw materials in the pretreatment step reduces their water content, thereby minimizing the reaction between magnesium chloride and water. A vacuuming step before the heating step places the raw materials in a vacuum environment, effectively preventing reaction with water vapor in the air during remelting. After the heating step, the liquid flux is solidified into a solid flux, which is then crushed to obtain granular or powdered flux products. The crushing process parameters can be set according to the particle size requirements of the finished flux product.

[0069] Preferably, in some optional embodiments of the present invention, the particle size of the flux product is 2 to 5 mm (e.g., particle size of 2 mm, 3 mm, 4 mm or 5 mm).

[0070] In some alternative embodiments of the present invention, the magnesium oxide content in the flux product is less than 0.5%.

[0071] In some embodiments of the present invention, the raw materials comprise, by mass percentage: NaCl: 39-61% and MgCl2: 39-61%.

[0072] Specifically, the percentages of NaCl and MgCl2 in the raw materials add up to 100%. For example, when the raw materials contain 39% NaCl, the percentage of MgCl2 is 61%.

[0073] In some optional embodiments of the present invention, the heating temperature in the heating step is 600-700°C (e.g., 600°C, 620°C, 640°C, 660°C, 680°C, or 700°C).

[0074] In some embodiments of the present invention, the vacuuming step further includes: injecting circulating coolant into the cooling ring, while simultaneously obtaining the furnace top humidity measured by a first hygrometer and the exhaust humidity measured by a second hygrometer.

[0075] Preferably, the temperature of the coolant is 10–20°C (e.g., 10°C, 12°C, 14°C, 16°C, 18°C, or 20°C).

[0076] Example 1

[0077] Weigh out NaCl: 59-61% and MgCl2: 39-41% by mass percentage.

[0078] The preparation method includes the following steps:

[0079] Pretreatment step: After drying the raw materials, add them to the furnace body 10 and mix them evenly;

[0080] Vacuuming step: Seal the furnace cover 20 onto the furnace body 10, connect the vent pipe 80 to the vacuum pump, and perform vacuuming on the furnace body 10;

[0081] Heating step: The raw material inside the furnace body 10 is heated by the heating element, and the hydrochloric acid gas inside the furnace body 10 is discharged through the vent pipe 80 to obtain liquid flux; wherein the heating temperature is 650℃ and the heating time (remelting time) is 4 hours;

[0082] In response to the end of the heating step, after the liquid flux has solidified into a solid flux, the solid flux is crushed to obtain the finished flux product.

[0083] After preparation, the flux product was tested, and the magnesium oxide content in the flux product was less than 0.5%.

[0084] Example 2

[0085] The only difference from Example 1 is the composition of the raw materials. In Example 2, the raw materials, by mass percentage, consist of: KCl: 59-61% and MgCl2: 39-41%.

[0086] In Example 2, the magnesium oxide content in the prepared flux product was less than 0.5%.

[0087] Example 3

[0088] The only difference from Example 1 is the composition of the raw materials. In Example 3, the raw materials, by mass percentage, comprised: KCl: 56-58% and MgCl2: 42-44%.

[0089] In Example 3, the magnesium oxide content in the prepared flux product was less than 0.5%.

[0090] Example 4

[0091] The only difference from Example 1 is the composition of the raw materials. In Example 3, the raw materials, by mass percentage, consist of: KCl: 39-41% and MgCl2: 59-61%.

[0092] In Example 4, the magnesium oxide content in the prepared flux product was less than 0.5%.

[0093] Therefore, those skilled in the art should recognize that although numerous exemplary embodiments of the present invention have been shown and described in detail herein, many other variations or modifications conforming to the principles of the present invention can be directly determined or derived from the disclosure of the present invention without departing from the spirit and scope of the invention. Thus, the scope of the present invention should be understood and construed as covering all such other variations or modifications.

Claims

1. An apparatus for preparing flux for aluminum and aluminum alloys, characterized in that, include: The furnace body has a receiving space inside and an opening is provided on the furnace body; A furnace cover, which is detachably installed at the opening of the furnace body; A sealing ring, wherein the sealing ring is annular and is disposed between the furnace body and the furnace cover; A heating element is disposed inside the furnace body and is used to heat the raw materials inside the furnace body; A vent pipe is provided at the top of the furnace body and is connected to the interior of the furnace body; A seal failure detection device is disposed on the outside of the sealing ring to provide a warning after the sealing ring fails. The sealing failure detection device includes: Multiple shape memory alloys are disposed on the outside of the sealing ring so that the shape memory alloys deform when heat leakage occurs due to failure at the corresponding position of the sealing ring. Multiple electronic tags and an electronic tag reader are provided. The electronic tags are disposed on the inside of the shape memory alloy so that the electronic tags are hidden from being read by the electronic tag reader, and the electronic tags are exposed from the inside of the shape memory alloy when the shape memory alloy is deformed, and then read by the electronic tag reader.

2. The preparation apparatus according to claim 1, characterized in that, Also includes: A phase change material is disposed between the sealing ring and the shape memory alloy, and the phase change material is thermally connected to the shape memory alloy.

3. The preparation apparatus according to claim 2, characterized in that, The outer peripheral surface of the sealing ring is provided with a process groove that penetrates the top surface of the sealing ring, but the process groove does not penetrate the bottom surface of the sealing ring, and the process groove does not penetrate the inner surface of the sealing ring. The preparation apparatus further includes a heat-conducting strip disposed within the process tank, which is thermally connected to the phase change material.

4. The preparation apparatus according to claim 1, characterized in that, The vent pipe is equipped with a filter screen and is configured to: evacuate the furnace body before the heating step and discharge the hydrochloric acid gas inside the furnace body during the heating step.

5. The preparation apparatus according to claim 1, characterized in that, A first hygrometer is installed on the top of the furnace body and / or the furnace cover, and a second hygrometer is installed on the ventilation pipe.

6. The preparation apparatus according to claim 1, characterized in that, Also includes: A cooling ring is fixed at the opening of the furnace body. The cooling ring has an annular groove. A sealing ring closes the upper opening of the annular groove or is inserted into the annular groove. The sealing ring and the bottom surface of the annular groove define an annular cooling cavity. The cooling ring is provided with a water inlet and a water outlet, which are connected to the annular cooling cavity.

7. A method for preparing a flux for aluminum and aluminum alloys, characterized in that, The preparation process of the flux for aluminum and aluminum alloys uses the preparation apparatus as described in any one of claims 1-6, and the preparation method includes: Pretreatment step: After drying the raw materials, add them to the furnace body and mix them evenly; Vacuuming step: Seal the furnace cover onto the furnace body, connect the vent pipe to the vacuum pump, and perform vacuuming on the furnace body; Heating step: The raw material in the furnace is heated by the heating element, and the hydrochloric acid gas in the furnace is discharged through the vent pipe to obtain liquid flux; Crushing step: In response to the end of the heating step, after the liquid flux solidifies into solid flux, the solid flux is crushed to obtain the flux product, wherein the particle size of the flux product is 2~5mm and the magnesium oxide content in the flux product is less than 0.5%.

8. The preparation method according to claim 7, characterized in that, The raw materials, by mass percentage, include: NaCl: 39-61%, MgCl2: 39-61%; In the heating step, the heating temperature is 600~700℃.

9. The preparation method according to claim 7, characterized in that, A first hygrometer is installed on the top of the furnace body and / or the furnace cover, and a second hygrometer is installed on the vent pipe; The preparation apparatus further includes a cooling ring, which is fixed at the furnace body opening. The cooling ring has an annular groove, and the sealing ring closes the upper opening of the annular groove or is inserted into the annular groove. The sealing ring and the bottom surface of the annular groove define an annular cooling cavity. The cooling ring is provided with a water inlet and a water outlet, which are connected to the annular cooling cavity. The vacuuming step also includes: Circulating coolant is injected into the cooling ring, and the humidity at the top of the furnace measured by the first hygrometer and the humidity of the exhaust gas measured by the second hygrometer are obtained simultaneously; wherein, the temperature of the coolant is cooling water at 10~20℃.

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