Double-hearth two-stage heating vacuum distillation furnace

Abstract

The application discloses a double-hearth two-stage heating vacuum distillation furnace, which comprises an evaporation furnace and a condensation furnace which are communicated through a gas passage, wherein the evaporation furnace comprises an evaporation furnace body and at least one top heating mechanism which is detachably arranged on the top of the evaporation furnace body; and the condensation furnace comprises a condensation furnace body, a side heating structure and a furnace cover, wherein the condensation furnace body is divided into a temperature control condensation chamber and a plurality of layers of multistage condensation chambers, and the gas passage can be combined or replaced according to the required reaction conditions of different materials. The vacuum distillation furnace can collect different metals through the gradient change of the temperature of the two hearths, reduces the process of secondary distillation of volatile matters after the furnace is stopped, can complete the processing of diversified raw materials, improves the work efficiency and reduces the processing cost; the modular top heating mode directly radiates heat to the materials, improves the heat utilization rate, can realize the working mode of stopping the furnace without stopping the work, helps to improve the work efficiency, and is convenient for completing the furnace cleaning, maintenance and solid material taking and placing.

Description

Technical Field

[0001] This invention relates to the field of vacuum distillation furnace technology, and specifically to a dual-furnace, two-stage heating vacuum distillation furnace. Background Technology

[0002] Vacuum distillation of non-ferrous metals mainly utilizes the differences in boiling points and saturated vapor pressures among different metals for smelting, refining, and purification. After distillation, the material is separated into residues and volatiles, both of which require collection devices. Existing vacuum distillation furnaces are mostly single-furnace designs, using a bottom heating element to heat the crucible and the metal within it. Temperature differences are controlled vertically to obtain liquid metals with different boiling points in different regions. The materials processed are mostly solid raw materials, and cooling and furnace opening operations are required during both feeding and discharging. For some high-melting-point materials, there are problems such as difficulty in cleaning the residue after distillation, and the limited crucible capacity prevents large-scale metal distillation.

[0003] Traditional vacuum furnaces use graphite crucibles to store materials and conduct heat to heat them. During the furnace start-up process, high-melting-point elements such as iron, nickel, aluminum, and silicon in the raw materials will accumulate to a high concentration during distillation. At high temperatures, these elements will undergo a carbonization reaction with the graphite crucible, corroding it. To ensure that the high-melting-point materials are removed in a liquid state (>1000℃), the graphite crucible is easily oxidized when removed at high temperatures. After cooling down, the high-melting-point alloy has solidified, causing the material to stick to the crucible. It is necessary to break the crucible to remove the material, which greatly increases production costs.

[0004] Chinese patent CN216473410U discloses a vacuum distillation furnace for separating zinc from zinc alloys. It employs a horizontal structure, with the distillation chamber and condensation chamber connected side-by-side. Electrodes are installed through the top of the furnace body and connected to the heating element inside. However, current methods often involve directly embedding the electrodes into the refractory brickwork during construction. This approach has the following problems:

[0005] 1. Materials can only be added and removed in a molten state. For some high-melting-point materials, there are problems such as difficulty in cleaning the residue after distillation.

[0006] 2. When repairing the electrodes and heating elements, the outer casing must be removed first, and then all the nearby refractory bricks must be removed. The disassembly and assembly are complicated and inefficient, which affects production efficiency.

[0007] 3. It cannot handle solid materials, which must be melted before being fed into the furnace. During the material transportation process, there are problems such as heat loss and corrosion of pipes by corrosive materials. In addition, for some high-melting-point raw materials, the residue after distillation is also difficult to clean.

[0008] 4. Since current furnace models are generally customized as a complete set, the heating mechanism cannot be adapted to other top-heating furnace bodies, resulting in poor adaptability;

[0009] 5. It cannot separate multiple metals.

[0010] 6. How to improve the evaporation and condensation rate of materials in the furnace.

[0011] Based on this, this application proposes a dual-furnace, two-stage heating vacuum distillation furnace. Summary of the Invention

[0012] To address the aforementioned issues, the inventors have provided a dual-furnace, two-stage heating vacuum distillation furnace, aiming to offer a novel heating approach (i.e., top heating of the evaporator furnace + side heating of the condenser furnace) to overcome the limitations of the original fixed bottom heating method. This allows for large-scale, high-efficiency production while facilitating furnace cleaning, maintenance, loading, and unloading. Furthermore, multiple evaporation channels and electromagnetic stirring mechanisms are employed to enhance the evaporation and condensation rates of the materials. Simultaneously, this addresses the issue of raw material adaptability in traditional vacuum distillation furnaces.

[0013] Specifically, the present invention is implemented as follows:

[0014] A dual-furnace, two-stage heating vacuum distillation furnace includes an evaporator and a condenser, which are connected by a gas duct. The evaporator includes:

[0015] The evaporator body is equipped with a liquid raw material feeding port and a residue discharge port.

[0016] At least one top heating mechanism is detachably mounted on the top of the evaporator body. In use, it seals the top opening of the evaporator body and is used to heat the material inside the evaporator body.

[0017] The evaporator can be filled with liquid raw materials through the liquid raw material feeding port and removed with liquid residue through the residue discharge port. Alternatively, solid raw materials can be added or solid residue can be removed by opening the top heating mechanism.

[0018] The condensing furnace includes:

[0019] The condensing furnace body is divided into a temperature-controlled condensing chamber and several multi-stage condensing chambers from bottom to top. The temperature-controlled condensing chamber is connected to the evaporating furnace body through an air duct. The several multi-stage condensing chambers are detachably installed on the condensing furnace body.

[0020] The side heating structure is located in the temperature-controlled condensing chamber and fixed to the side wall of the condensing furnace body. It is used to keep the temperature-controlled condensing chamber warm and to perform secondary evaporation of the molten metal inside the temperature-controlled condensing chamber. The multi-stage condensing chamber includes: secondary condensing chamber, tertiary condensing chamber, quaternary condensing chamber, etc., and the specific number is arranged according to the actual situation.

[0021] The furnace cover is removably mounted on top of the condensing furnace body.

[0022] Furthermore, the top heating mechanism includes:

[0023] The single-cast body is made of refractory and heat-insulating materials and is used for sealing the evaporator furnace body and heat insulation.

[0024] The electrode pins are located on the primary casting body and extend into the evaporator body from the outside of the primary casting body.

[0025] The evaporation electrode has one end connected to the top of the electrode pin and the other end connected to the power supply.

[0026] The top heating element is located inside the evaporator and is connected to the bottom of the electrode pins. It is used to heat the material inside the evaporator.

[0027] Furthermore, since the refractory casting body needs to be sintered at high temperature, if the electrode pin is directly cast and sintered with the primary casting body, the following situations will occur: (1) The electrode pin and the primary casting body are tightly bonded. During the sintering process, the electrode pin and the primary casting body expand at high temperature, and the electrode pin or the primary casting body will be squeezed and cracked; (2) If the bond is not tight enough, metal vapor will leak out from the gap at the joint between the two.

[0028] Therefore, this application first creates mounting holes for electrode pins on the primary casting body. After sintering, a flexible secondary casting body is used to install the electrode pins into the mounting holes. The flexibility of the secondary casting body helps avoid cracking of the primary casting body or electrode pins, while also ensuring the airtightness of the furnace body and preventing metal vapor leakage.

[0029] Furthermore, the top heating mechanism also includes a housing, which is mounted on the primary casting body and forms an electrode cavity between the housing and the top of the primary casting body. The evaporation electrode is inserted into the electrode cavity and connected to the electrode pin.

[0030] Furthermore, the bottom of the primary casting body is shaped like a boss, and the boss portion extends into the interior of the evaporator body, with the sidewall of the boss in contact with the inner wall of the opening at the top of the evaporator body.

[0031] Furthermore, the evaporation electrode and the electrode pins are connected by a connector.

[0032] Furthermore, the top heating mechanism also includes:

[0033] An electrode busbar module, connected to the evaporation electrode, is used to collect the three-phase evaporation electrodes to the power connection point of the top heating mechanism near the power source.

[0034] Furthermore, the electrode bus module includes:

[0035] The busbar is arranged along the outer edge of the top heating mechanism. One end of the busbar is connected to the evaporation electrode, and the other end is connected to the power supply. The busbar is used to gather the three-phase evaporation electrodes to the power connection point of the top heating mechanism near the power supply.

[0036] Several insulating blocks are evenly distributed along the outer edge of the top heating mechanism and converge from the evaporation electrode to the junction point. The busbar is fixed on the insulating blocks.

[0037] Furthermore, an induction coil is provided at the bottom of the evaporation furnace body, which is used to electromagnetically stir the molten metal inside the evaporation furnace body.

[0038] Furthermore, the evaporator and condenser are configured in a one-to-many or many-to-one manner.

[0039] Furthermore, the gas duct is connected to the evaporator and the condenser on both sides, and the outer side of the gas duct forms a series structure with the evaporator and the condenser. The gas duct is installed between the evaporator body and the condenser body and is detachably connected. Its interior is a shape that narrows from one end of the evaporator body to the middle of the gas duct, with the narrow opening biased towards the evaporator side, and then gradually widens from the narrow opening towards the condenser body. Its exterior is a cylindrical structure. Its overall structure is made of graphite, silicon carbide or other materials. It is installed between the evaporator body and the condenser body in an assembled manner. It can also be configured according to the material conditions as a horizontal shape (a), a shape that gradually narrows from the evaporator body to the condenser body (b), a shape that gradually widens from the evaporator body to the condenser body (c), a U-shaped structure (e), or a shape that narrows from one end of the evaporator body to the middle of the gas duct and then gradually widens from the middle of the gas duct towards the condenser body (d).

[0040] in:

[0041] (a) The structure is that of an airway used under normal circumstances;

[0042] (b) The structure can control the distillation time and reflux rate by controlling the size and length of the gas passage opening: the structure allows the high-boiling-point substance vapor to be condensed and refluxed when the volatiles pass through the gas passage, resulting in better separation of the volatiles collected in the condensation chamber and the residue in the evaporation chamber.

[0043] (c) The structure can control the opening size of the gas passage to prevent the backflow of volatiles and shorten the distillation time, and can handle materials that require efficient evaporation.

[0044] (d) The structure's internal shape is characterized by a narrow throat that narrows towards one side of the evaporator, gradually widening towards the condenser. The total length of the gas passage and the position of the narrow throat can be adjusted to achieve different separation effects. Its working principle is as follows: A vacuum extraction port is installed at the condenser end. Due to the presence of high-temperature steam in the evaporator, a pressure difference is created between the evaporator and condenser. Steam flows from the evaporator to the condenser through the gas passage. The gas is compressed at the narrow throat, forming a high-speed compressed gas, which then rapidly expands after passing through the throat, creating an even higher flow rate. This achieves the effect of a Laval nozzle, rapidly cooling the volatiles in the condenser and increasing the pressure difference between the evaporator and the narrow throat, thus accelerating the steam outflow. Simultaneously, the narrow throat features sloping structures on both sides, where the gas reaches maximum pressure. Upon compression, it releases heat, facilitating the condensation and separation of high-boiling-point substances. The condensate flows back through the slopes, with high-boiling-point substances returning to the evaporation chamber, while low-boiling-point substances rapidly flow through the narrow throat to the condensation chamber, achieving a flow separation effect and dynamic, efficient distillation. This structure increases the pressure difference between the evaporation and condensation chambers, making it less likely for high-boiling-point substances to volatilize in the evaporation chamber, while low-boiling-point substances rapidly condense in the condensation chamber after passing through the gas passage. For alloy materials with similar boiling points, this allows for more precise and effective separation.

[0045] (e) The structure is U-shaped, and the gas molecules will collide with the baffle multiple times, condensing faster. The condensed liquid will be fractionated in the gas channel and flow back to the evaporation chamber and the condensation chamber respectively. The gas that is easier to condense will condense in the first half and flow back to the evaporation chamber, while the gas that is not easy to condense will enter the second half of the gas channel and the condensation chamber to condense, and finally flow into the condensation chamber. This ensures that the high-boiling-point material in the evaporation chamber can be retained in the residue in the evaporation chamber as much as possible.

[0046] Working principle of the invention:

[0047] During production, the raw materials can be placed into the evaporator by removing the top heating mechanism and adding solid raw materials or liquid raw materials through the liquid raw material inlet. The raw materials are first distilled at high temperature in the evaporator, and the residue is collected in the evaporator. At the same time, because the vacuum system is connected above the condenser, a vacuum negative pressure is formed in the condenser. Due to the presence of high-temperature steam in the evaporator, a pressure difference is formed between the evaporator and the condenser. The primary volatile gas evaporated in the evaporator enters the temperature-controlled condenser through the gas passage with a narrow throat structure for condensation. When the gas passes through the gas passage with the narrow throat structure, the gas is compressed at the narrow throat to form a high-speed compressed gas. After passing through the narrow throat, it expands rapidly to form a gas with a higher flow rate and achieves rapid cooling, achieving the effect of a Laval nozzle. According to Bernoulli's principle, higher flow velocities result in lower pressures. The high-velocity gas and the condensing gas create a greater pressure difference between the evaporator and the condenser chamber. Simultaneously, because the gas reaches its maximum pressure at the narrow throat, it is compressed and releases heat, which is more conducive to the condensation and separation of high-boiling-point substances. The condensate flows back through the ramp, with high-boiling-point substances returning to the evaporation chamber, while low-boiling-point substances can quickly flow through the narrow throat to the condenser chamber, thus achieving a diversion effect and realizing dynamic and efficient distillation. Furthermore, the electromagnetic stirring mechanism at the bottom of the evaporation chamber agitates the material, increasing the evaporation area and heat transfer efficiency, maximizing evaporation efficiency. After entering the condenser chamber, the gas undergoes secondary low-temperature distillation using a side-heating structure. The secondary volatiles enter the multi-stage condenser chamber above. Based on the temperature gradient changes in the multi-stage condenser chamber, different metals can be condensed and collected in their respective chambers, thus achieving the separation and collection of multiple metals.

[0048] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0049] (1) By adopting a dual-furnace two-stage heating method, different metals can be collected in different areas through the temperature gradient of the two furnaces. This reduces the need for secondary distillation of volatiles after furnace shutdown, enabling diversified raw material processing, improving work efficiency, saving working time, and reducing processing costs.

[0050] (2) The top heating mechanism of the evaporator adopts a modular top heating method, which can be combined with different top heating furnace types to realize the conversion of different functional furnace types. One modular top heating mechanism can also be equipped with multiple furnace bodies to realize alternating operation and realize the working mode of stopping the furnace without stopping the work, making reasonable use of time and thus improving work efficiency. In addition, after the top heating mechanism is removed, it is convenient to complete furnace cleaning, maintenance, and solid material handling.

[0051] (3) The top heating mechanism replaces the original brick structure with a pre-embedded cast-in-place structure, resulting in better airtightness and less heat loss. Furthermore, by disassembling and reassembling the electrode pins as a whole, the evaporation electrode is isolated from the top heating element, further reducing heat loss. During vacuum evaporation, it is essential to ensure that the pressure in the evaporation zone is higher than that in the condensation zone to allow the volatilized metal gas to flow directionally towards the condensation chamber. This top heating module, when used in a vacuum furnace, prevents the volatilized metal vapor from escaping upwards and condensing, thus preventing electrode short circuits and ensuring airtightness. When maintenance is required, the electrode structure can be directly replaced, reducing maintenance cycles and costs and improving work efficiency.

[0052] (4) A detachable gas duct module structure is adopted between the evaporator and the condenser. Different types of gas ducts can be selected according to the actual situation. A magnetic stirring mechanism is set below the distillation furnace to improve the evaporation efficiency of the material in the furnace and reduce power consumption.

[0053] (5) The condensing furnace adopts a side heating method, so there is no need to remove the heating element when the furnace is shut down, and the material can be discharged and other work can be carried out. This can effectively improve work efficiency. The detachable top cover and multi-stage condensing chamber design can effectively improve the efficiency of daily maintenance and facilitate the discharge and cleaning of solid materials.

[0054] (6) By using a secondary evaporation method, materials with relatively low boiling points in the condensed primary volatiles can be effectively separated, thereby improving purity.

[0055] (7) The double furnace chamber of the vacuum distillation furnace can be constructed by selecting refractory bricks to form the furnace body according to the properties of the material, which avoids the material from reacting with the furnace body. The material inside the furnace can also be released from the furnace in liquid form, which can reduce the material residue inside the furnace, reduce the difficulty of cleaning the vacuum furnace, and crucibles can be used to store materials that do not react with the crucibles. Attached Figure Description

[0056] Figure 1 This is a schematic diagram of the structure of the dual-furnace, two-stage heating vacuum distillation furnace in Example 1;

[0057] Figure 2 This is a schematic diagram of the top heating mechanism in Example 1;

[0058] Figure 3 This is a schematic diagram of the electrode bus mode in Example 1;

[0059] Figure 4 This is a schematic diagram of the structure of the dual-furnace, two-stage heating vacuum distillation furnace in Example 2;

[0060] Figure 5 This is a schematic diagram of the top heating mechanism in Example 2;

[0061] Figure 6This is a schematic diagram of the structure of the dual-furnace, two-stage heating vacuum distillation furnace in Example 3;

[0062] Figure 7 This is a schematic diagram of the internal structure of the airway in Example 4;

[0063] Figure 8 This is a schematic diagram of the layout connecting one evaporator and multiple condensers in Example 5;

[0064] Figure 9 This is a schematic diagram showing the layout of multiple evaporators and one condenser in Example 5.

[0065] Figure label:

[0066] 1-Evaporator body; 11-Liquid raw material feed port; 12-Residue discharge port; 2-Condensation furnace body; 21-Temperature-controlled condensing chamber; 23-Secondary condensing chamber; 22-Side heating structure; 23-Evaporation channel; 24-Secondary condensing chamber; 25-Furnace cover; 3-Gas passage; 41-Primary casting body; 42-Secondary casting body; 43-Top heating element; 44-Evaporation electrode; 45-Electrode pin; 46-Connector; 47-Shell; 5-Induction coil; 61-Busbar; 62-Insulating block; 7-Transformer. Detailed Implementation

[0067] The present invention will now be described in further detail with reference to specific embodiments and accompanying drawings.

[0068] Example 1

[0069] like Figure 1 As shown, this embodiment provides a dual-furnace, two-stage heating vacuum distillation furnace, including an evaporator and a condenser. The evaporator and condenser are connected by a gas channel 3. The evaporator distills the raw material, and the volatiles enter the evaporator, which has a relatively lower temperature, along the gas channel 3 for condensation and collection.

[0070] Specifically, the evaporation furnace includes an evaporation furnace body 1 and at least one top heating mechanism. The evaporation furnace body 1 is entirely constructed of refractory bricks and has a liquid raw material feeding port 11 and a residue discharge port 12. The liquid raw material feeding port 11 is used to add liquid raw materials, and the residue discharge port 12 is used to discharge liquid residues for subsequent ingot casting processes. The top heating mechanism is detachably mounted on the top of the evaporation furnace body 1. Therefore, the top heating mechanism can be removed from the top of the evaporation furnace body 1, which facilitates daily furnace cleaning, maintenance, and handling of solid materials. Furthermore, one top heating mechanism can be used with multiple evaporation furnace bodies 1 (i.e., during production, one top heating mechanism works with one evaporation furnace body 1; after the furnace is shut down, the top heating mechanism can be transferred to another evaporation furnace body 1), enabling alternating operation and a continuous operation mode, thus improving work efficiency by making reasonable use of time. In addition, due to the top heating method, the limitations of the crucible in bottom heating methods are eliminated, enabling large-scale material production. Multiple top heating mechanisms can also be installed on a larger evaporator body 1. The materials inside the furnace are heated together by the top heating mechanisms, which ensures heating uniformity and enables larger batch production.

[0071] Furthermore, such as Figure 2 As shown, the top heating mechanism includes: a shell 47, an evaporation electrode 44, a primary casting body 41, electrode leads 45, and a heating element 43. The primary casting body 41 is integrally cast from refractory material and then sintered. It can be square, round, arc-shaped, or in other forms, and the specific shape can be freely selected according to the furnace type and its installation position, without limitation here. The integral casting method can effectively ensure airtightness and heat insulation performance. The primary casting body 41 is detachably connected to the evaporation furnace body 1. The specific method is not limited here, but preferably, the primary casting body 41 and the shell 47 are integrated structures. The shell 47 at the installation position is fixed to the outer shell of the evaporation furnace body 1 by a flange. During disassembly and assembly, the shell 47 and the primary casting body 41 can be directly disassembled and assembled, which can effectively improve the efficiency of maintenance. The bottom of the primary casting body 41 is shaped like a protrusion, and the protrusion extends into the interior of the evaporator body 1. The two sides of the protrusion press against the evaporator body 41, and the downward pressure due to its own weight can reduce the upward force of the metal gas during operation, further improving the airtightness. The bottom of the shell 47 is fixed to the protrusion, and the side wall of the protrusion contacts the inner wall of the opening at the top of the evaporator body 1, thereby blocking the upward metal vapor and preventing the metal vapor from corroding the shell 47.

[0072] The outer end of the evaporation electrode 14 is connected to the power supply via an electrode busbar module, and the inner end extends into the electrode cavity between the housing 47 and the primary casting body 41. It is connected to the electrode pin 45 via a connector 46. The electrode pin 45 is located on the primary casting body 41 and extends from the top of the primary casting body 41 through it into the evaporation furnace body 1. Its extension length can be adjusted according to actual conditions and is not limited here. One end of the electrode pin 45 extending into the evaporation furnace body 1 is connected to the heating element 43 via a screw, thereby supplying power to the heating element 43.

[0073] The electrode busbar module is located outside the housing 47 and is used to gather the three-phase evaporation electrodes 44 distributed around the circumference of the housing 47 into a position that is convenient for connection with the transformer 7. This reduces the auxiliary complexity and assembly difficulty of the connection between the evaporation electrodes 44 and the transformer 7, and improves assembly efficiency.

[0074] Specifically, in this embodiment, such as Figure 3 As shown, the electrode busbar module includes multiple busbars 61 and several insulating blocks 62. The busbars 61 are machined into an arc shape that matches the outer circumference of the housing 47, and are used to lead the three-phase evaporation electrodes 44 to a power convergence point at a certain location on the outer circumference of the housing 47, and then connect to the transformer 7 from the power convergence point. Preferably, to reduce costs, two of the evaporation electrodes can be converged to a third evaporation electrode, i.e.:

[0075] The insulating block 62 is divided into two groups, which are used to fix two groups of busbars 61 respectively. The insulating block 62 is arranged circumferentially from two of the evaporation electrodes 44 to the third electrode 44 (the power connection point) and fixed on the housing 47. The two groups of busbars 61 are distributed and fixed on the two groups of insulating blocks 62, thereby fixing the two groups of busbars 61 respectively. At the same time, the busbars 61 are suspended to avoid the housing 47 from conducting electricity and to ensure electrical safety.

[0076] Furthermore, the condensing furnace includes: a condensing furnace body 2, a side heating structure 22, and a furnace cover 25. The condensing furnace body 2 is entirely constructed of refractory bricks and is connected to a vacuum system to perform vacuuming operations on the evaporating furnace body 1 and the condensing furnace body 2. The condensing furnace body 2 is divided from bottom to top into a lower-level temperature-controlled condensing chamber 21 and several upper-level multi-stage condensing chambers. The temperature-controlled condensing chamber 21 is connected to the evaporating furnace body 1 via a gas duct 3. The multi-stage condensing chambers are arranged in a layered structure above the temperature-controlled condensing chamber 21 and are connected to it via an evaporation channel 23. The upper-level multi-stage condensing chambers sequentially perform secondary volatile matter condensation, tertiary volatile matter condensation, ..., N-stage volatile matter condensation, thereby condensing and collecting metals with different boiling points in different levels of condensing chambers, achieving the separation and collection of multiple metals. The furnace cover 25 and the multi-stage condensing chambers are both detachable to facilitate the removal of the metals collected in each level of condensing chamber.

[0077] For ease of understanding, in this embodiment, the multi-stage condensing chamber is only provided with a second-stage condensing chamber 24. The metal vapor (first-stage volatiles) evaporated from the evaporator body 1 enters the temperature-controlled condensing chamber 21 through the gas passage 3. The temperature-controlled condensing chamber 21 is kept warm by the side heating structure 22, and the metal liquid (obtained by condensation of the first-stage volatiles) in the temperature-controlled condensing chamber 21 is subjected to secondary evaporation. The secondary volatiles rise and enter the second-stage condensing chamber 3 for condensation and collection.

[0078] Furthermore, the side heating structure includes a side electrode and a side heating element. The side electrode is inserted into the temperature-controlled condensing chamber 21 from the side of the condensing furnace body and is fixedly connected to the side heating element, so that the side heating element is hung on the side inside the temperature-controlled condensing chamber 21 for secondary evaporation.

[0079] Furthermore, the outer side of the gas duct 3 forms a left-right series structure together with the evaporator and condenser; the gas duct 3 is installed between the evaporator body 1 and the condenser body 2 and is detachably connected. Its outer surface is a cylindrical structure, and its overall structure is made of graphite, silicon carbide, or other materials. It is installed between the evaporator body and the condenser body in an assembled manner. It can also be configured as a horizontal shape, a shape that gradually narrows from the evaporator body to the condenser body, a shape that gradually widens from the evaporator body to the condenser body, or a U-shaped structure, depending on the material.

[0080] Example 2

[0081] Based on Example 1, since the primary casting body 41 and electrode pins 45 will undergo high-temperature expansion under high-temperature conditions, if the electrode pins 45 are directly cast onto the primary casting body 41, the high-temperature expansion of the electrode pins 45 and the primary casting body 41 may cause mutual compression, resulting in cracks in the electrode pins 45 and / or the primary casting body 41, affecting performance. Therefore, if... Figure 4-5 As shown, this embodiment employs a mounting hole extending from the top to the bottom of the primary casting body 41. The electrode pin 45 is placed within the mounting hole, and a flexible secondary casting body 42 is provided in the gap between the electrode pin 45 and the wall of the mounting hole. The secondary casting body 42 seals the gap between the electrode pin 45 and the mounting hole, ensuring airtightness and preventing metal gases from escaping through the gap. Simultaneously, the flexible material provides a buffer when the relatively rigid electrode pin 45 and the primary casting body 41 expand at high temperatures, effectively preventing damage to the electrode pin 45 and / or the primary casting body 41 due to high-temperature expansion, thus improving service life.

[0082] Example 3

[0083] Based on Example 2, in order to accelerate the evaporation efficiency, therefore, as Figure 6As shown, an induction coil 5 is installed at the bottom of the evaporator body 1. The power supply generates a large current after AC-DC-AC frequency conversion, which generates a strong magnetic field through the induction coil 5, and thus generates a strong electromagnetic force. The liquid metal is subjected to the electromagnetic force, which will generate strong stirring, thereby improving the volatilization efficiency of the raw materials.

[0084] Example 4

[0085] In this embodiment, the gas duct 3 is detachably wedged horizontally into a reserved position formed by the furnace bricks and connected to the evaporator body 1 and the condenser body 2 to avoid the problem of not being able to repair the gas duct 3 independently when it becomes blocked. Its external shape is cylindrical, and its overall structure is made of graphite, silicon carbide, or other materials. It is assembled between the evaporator body and the condenser body, and different internal structures can be replaced according to actual conditions to adapt to different production requirements.

[0086] Specifically, such as Figure 7 As shown, the interior of the gas duct 3 can be configured as follows: horizontal (a), gradually narrowing from the evaporator body 1 to the condenser body 2 (b), gradually widening from the evaporator body 1 to the condenser body 2 (c), a U-shaped structure (e), or narrowing from one end of the evaporator body 1 to the middle of the gas duct 3, and then gradually widening from the middle of the gas duct 3 to the condenser body 2 (d). Wherein:

[0087] (1) As Figure 7 (a) shows the airway used under normal circumstances;

[0088] (2) Figure 7 As shown in (b), when the gas channel 3 gradually narrows from the evaporator body 1 to the condenser body 2, the steam velocity at the connection between the evaporator body 1 and the gas channel 3 (large opening) is lower than that at the connection between the condenser body 2 and the gas channel 3 (small opening). In this case, the steam easily flows back to the evaporator body 1 within the gas channel 3. The gas reaching the condenser body 2 is the lower-boiling-point portion of the metal gas component, which can improve the purity of the low-boiling-point metal collected in the condenser body 2. Simultaneously, the refluxed steam undergoes multiple distillation separations, allowing for a more thorough separation of high-boiling-point residues and low-boiling-point volatiles. This structure can be used when the product to be collected (evaporator volatiles) has a lower boiling point compared to impurities. For example, this structure can be used when preparing 4N or higher purity cadmium using Pb-Cd alloy as raw material, where the boiling points of the two metals differ significantly (boiling point T under vacuum conditions of 100 Pa). Pb =1110K,T Cd =594K), to obtain high-purity volatiles, after gas-channel distillation through this structure, purer volatiles (Cd) can be obtained, thus obtaining refined cadmium products.

[0089] (3) Figure 7As shown in (c), when the gas channel 3 gradually widens from the evaporator body 1 to the condenser body 2, the steam velocity at the connection between the evaporator body 1 and the gas channel 3 (small opening) is greater than that at the connection between the condenser body 2 and the gas channel 3 (large opening). At this time, the volatiles in the evaporator body 1 flow rapidly through the gas channel 3 to the condenser body 2, which is beneficial for quickly removing low-boiling-point impurities from the molten metal in the evaporator body 1. Simultaneously, the widening of the gas channel 3 from the evaporator body 1 to the condenser body 2 prevents the backflow of low-boiling-point impurity vapors, thus improving the purity of the residual molten metal in the evaporator body 1 and shortening the distillation time. This method can be used when the product to be collected (evaporator chamber residue) has a higher boiling point than the impurities, or when materials require efficient evaporation. For example, when using zinc slag (Zn-Fe, Sn-Zn) as raw material to recover Zn, the boiling points of Zn and impurity elements differ greatly (boiling point T is much higher under vacuum conditions of 100 Pa). Zn =681K,T Sn =1685K,T Fe =1859K), when Zn reaches its boiling point and begins to evaporate, the impurity elements Fe and Sn have not yet reached their boiling points and do not volatilize. This structure can quickly evaporate Zn vapor while avoiding Zn vapor backflow, thus achieving efficient and energy-saving recovery of zinc from zinc slag.

[0090] (4) Figure 7 As shown in (d), the gas channel narrows from one end of the evaporator body 1 towards the middle of the gas channel 3, and then gradually widens from the middle of the gas channel 3 towards the condenser body 2. The total length of the gas channel and the position of the narrowing can be adjusted according to different situations to achieve different separation effects. When the vacuum port at the end of the condenser body 2 is evacuated, the presence of high-temperature steam in the evaporator body 1 creates a pressure difference with the condenser body 2. The steam flows from the evaporator body 1 to the condenser body 2 through the gas channel 3. The gas is compressed at the narrow throat, forming a high-speed compressed gas, and then rapidly expands after passing through the narrow throat, forming a gas with an even higher flow rate. This achieves the effect of a Laval nozzle, realizing rapid cooling of the volatiles in the condenser body 2, increasing the pressure difference between the evaporator body 1 and the narrow throat of the gas channel 3, and accelerating the outflow speed of the steam. Simultaneously, both sides of the narrow throat have a sloping structure, where the gas reaches maximum pressure and releases heat upon compression, facilitating the condensation and separation of high-boiling-point substances. The condensate flows back through the slope, with high-boiling-point substances returning to evaporator 1, while low-boiling-point substances rapidly flow through the narrow throat to condenser 2, achieving a diversion effect and realizing dynamic and efficient distillation. This structure increases the pressure difference between evaporator 1 and condenser 2, making it less likely for high-boiling-point substances in evaporator 1 to volatilize, while low-boiling-point substances quickly condense in condenser 2 after passing through the gas passage. For alloy materials with similar boiling points, this allows for more precise and effective separation. For example, in the separation of Sb-Pb alloys to prepare refined antimony and refined lead, the boiling points of Sb and Pb elements are not significantly different under vacuum conditions (boiling point T at 100 Pa). Sb =783K,TPb =1110K), the evaporation process has a high pressure in the evaporation chamber, which makes it difficult for Pb to volatilize. When a small amount of Pb volatilizes, the Pb vapor is easy to condense due to the high pressure on the evaporation chamber side. It is cooled and flows back to the evaporator side before reaching the narrow throat. When the vapor passes through the narrow throat of the gas passage, the Sb vapor is rapidly passed through the narrow throat due to the increased pressure and then cooled in the condensation chamber. Therefore, this method can separate metals with similar boiling points that are difficult to separate by conventional distillation methods, and obtain two products with high purity at the same time.

[0091] (5) Figure 7 As shown in (e), the gas channel 3 has a loop-shaped internal structure. Gas molecules collide with the baffle multiple times, condensing more quickly. The condensed liquid undergoes fractionation in the gas channel 3, flowing back to the evaporator 1 and the condenser 2 respectively. The more easily condensable gas condenses in the first half and flows back to the evaporator 1, while the less easily condensable gas enters the second half of the gas channel 3 and the condenser 2 for condensation, finally converging into the condenser. This ensures that high-boiling-point materials in the evaporator are retained as much as possible in the evaporator residue. This method can be used when the evaporation feedstock contains high-boiling-point precious metals. For example, when using lead with a high Ag content as feedstock to separate Ag and Pb, to minimize Ag loss, a loop-shaped internal gas channel can be used. Ag vapor passes through the gas channel baffle during volatilization, condensing in the first half of the gas channel, with most flowing back to the evaporator, reducing Ag loss and simultaneously lowering the impurity content in the lead product produced by the condenser.

[0092] Example 5

[0093] like Figure 8 As shown, in this embodiment, the evaporator and condenser are configured in a one-to-many manner. Multiple condensers are distributed in a planetary pattern around the larger evaporator. The primary volatiles evaporated from the evaporator are collected by multiple condensers. Multiple sets of products can be collected at the same time, which improves production efficiency. When one condenser is damaged and needs to be replaced, the others can still work normally without affecting the production schedule.

[0094] like Figure 9 As shown, the evaporator and condenser are also configured in a many-to-one manner. Multiple evaporators are distributed in a planetary pattern around the larger condenser. Evaporation is carried out through multiple evaporators, and products from different evaporators can be collected simultaneously for alloy preparation. If one evaporator is damaged, it will not affect the production of other furnaces.

[0095] The above examples illustrate the present invention only to aid in understanding it and are not intended to limit the scope of the invention. Those skilled in the art can make various simple deductions, modifications, or substitutions based on the principles of this invention.

Claims

1. A dual-furnace, two-stage heating vacuum distillation furnace, comprising an evaporator and a condenser, wherein the evaporator and the condenser are connected by a gas duct (3), characterized in that, The evaporation furnace includes: An evaporator body (1) is provided with a liquid raw material feeding port (11) and a residue discharge port (12). At least one top heating mechanism is detachably installed on the top of the evaporator body (1). When in use, it seals the top opening of the evaporator body (1) and is used to heat the material inside the evaporator body (1). The condensing furnace includes: The condensing furnace body (2) is divided into a temperature-controlled condensing chamber (21) and several multi-level condensing chambers from bottom to top. The temperature-controlled condensing chamber (21) is connected to the evaporating furnace body (1) through a gas duct (3). The several multi-level condensing chambers are detachably installed on the condensing furnace body (2). A side heating structure (22) is provided in the temperature-controlled condensing chamber (21) and fixed on the side wall of the condensing furnace body (2) for heat preservation of the temperature-controlled condensing chamber (21) and secondary evaporation of the metal liquid in the temperature-controlled condensing chamber (21); The furnace cover (25) is detachably mounted on top of the condensing furnace body (2); The top heating mechanism includes: The single-cast body (41) is made of refractory and heat-insulating material and is used to seal the evaporator body (1) and provide heat insulation. The electrode pin (45) is located on the primary casting body (41) and extends into the evaporator body from the outside of the primary casting body (41) after passing through the primary casting body (41); The evaporation electrode (44) is connected at one end to the top of the electrode pin (45) and at the other end to the power supply. The top heating element (43) is located inside the evaporator body (1) and is connected to the bottom end of the electrode pin (45) for heating the material inside the evaporator body (1); The primary casting body (41) is provided with mounting holes, and the electrode pins (45) are fixed in the mounting holes by the secondary casting body (42), which is made of flexible material.

2. The dual-furnace, two-stage heating vacuum distillation furnace as described in claim 1, characterized in that, The top heating mechanism further includes a housing (47), which is installed on the primary casting body (41) and forms an electrode cavity between it and the top of the primary casting body (41). The evaporation electrode (44) is inserted into the electrode cavity and connected to the electrode pin (45).

3. The dual-furnace, two-stage heating vacuum distillation furnace as described in claim 1, characterized in that, The evaporation electrode (44) and electrode pin (45) are connected by a connector (46).

4. The dual-furnace, two-stage heating vacuum distillation furnace as described in claim 1, characterized in that, The top heating mechanism also includes: The electrode bus module is connected to the evaporation electrode (44) and is used to gather the three-phase evaporation electrodes (44) to the power connection point of the top heating mechanism near the power source.

5. The dual-furnace, two-stage heating vacuum distillation furnace as described in claim 4, characterized in that, The electrode bus module includes: Busbar (61) is arranged along the outer edge of the top heating mechanism. One end of it is connected to the evaporation electrode (44), and the other end is connected to the power supply. The busbar (61) is used to gather the three-phase evaporation electrodes (44) to the power supply junction point of the top heating mechanism near the power supply. Several insulating blocks (62) are evenly distributed along the outer edge of the top heating mechanism and converge from the evaporation electrode (44) to the power connection point. The busbar (61) is fixed on the insulating blocks (62).

6. The dual-furnace, two-stage heating vacuum distillation furnace as described in claim 1, characterized in that, The bottom of the evaporator body (1) is provided with an induction coil (5), which is used to electromagnetically stir the liquid metal inside the evaporator body (1).

7. The dual-furnace, two-stage heating vacuum distillation furnace as described in claim 1, characterized in that, The evaporator and condenser are configured in a one-to-many or many-to-one manner.

8. The dual-furnace, two-stage heating vacuum distillation furnace as described in claim 1, characterized in that, The outer side of the air duct (3) is in contact with air, and the outer side of the air duct (3) together with the evaporator and the condenser form a left-right series structure. The air duct (3) is detachably connected to the evaporator body (1) and the condenser body (2) respectively. The airway (3) is configured as follows: horizontal; or The shape gradually narrows from the evaporator body (1) to the condenser body (2); or The shape of the furnace gradually widening from the evaporator body (1) to the condenser body (2); or circular structure; or The shape is formed by narrowing the opening from one end of the evaporator body (1) towards the middle of the gas passage (3), and then gradually widening from the middle of the gas passage (3) towards the condenser body (2).

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