A metal refining apparatus

Abstract

This invention provides a metal refining apparatus, comprising: a primary purification device with a first crucible, the first crucible having three temperature zones externally: an upper heating zone, a lower heating zone, and a bottom heating zone; and a secondary purification device with a second crucible held by a clamp connected to a separation block. The clamp controls the opening and closing of a copper clamp (a clamp with upper and lower lugs on the crucible) via the separation block, achieving the purpose of clamping and releasing the crucible. The copper clamp can conduct current when holding the crucible in place. After metal refining, the clamp is released to facilitate crucible removal. An inverter power supply and a step-down transformer are connected, and the output current of the step-down transformer is conducted to the second crucible through a copper plate. This invention employs online infrared temperature measurement, featuring a compact probe, easy installation, strong anti-interference capability, good linearity, and a large distance coefficient ratio, enabling measurement in confined spaces and improving temperature measurement accuracy.

Description

Technical Field

[0001] This invention relates to the field of alkali metal production technology, and more particularly to a metal refining apparatus. Background Technology

[0002] The molten salt process produces metals with high impurity content, mainly including heavy metals, electrolytes, graphite, silicon, and compounds, nitrides, and oxides of carbon and silicon. These impurities severely affect product quality; therefore, the crude metal must undergo purification to remove impurities before meeting the quality requirements of the next process or other users. Currently, metal refining processes employ a two-step refining method, utilizing the density difference between impurities and metals to purify them through sedimentation. The main equipment for metal purification is a pit-type resistance heating furnace. The refining crucible is placed inside the pit furnace chamber. When the heating element is energized, heat is naturally conducted from the air to the outer wall of the refining crucible, achieving the purpose of heating the metal. The furnace temperature is measured by an insertion thermocouple and transmitted to a temperature control cabinet where a silicon controlled rectifier (SCR) controls the furnace temperature. The control of metal temperature during the purification process directly affects the quality of the metal product.

[0003] Existing metal purification devices have the following problems that cannot be solved during long-term use:

[0004] (1) Uneven heating in different areas of the metal. The heating elements in the metal refining furnace are arranged with varying density in different areas of the furnace, resulting in different temperatures in each area. The heating rates in the upper, middle, and lower zones of the resistance furnace differ significantly, causing large temperature differences in the furnace chamber during the initial heating phase. Even if the heating elements are arranged with the same density in different areas of the furnace, the temperature in each area is still inconsistent due to the different insulation effects in each area of ​​the refining furnace.

[0005] (2) The temperature measurement location is not representative. The furnace temperature reflected by different temperature control points in the refining furnace is also different. Inaccurate temperature measurement location causes the metal temperature in different areas of the refining crucible to be inconsistent, which affects the removal effect of impurities in the metal. Summary of the Invention

[0006] The purpose of this invention is to provide a metal refining apparatus that solves the problems of uneven temperature and poor refining effect in the metal refining process, and achieves precise temperature control and energy saving in the refining furnace.

[0007] To achieve the above objectives, the present invention provides the following technical solution:

[0008] A metal refining apparatus, comprising:

[0009] The primary purification device includes a first crucible, and the outside of the first crucible is provided with three temperature zones: an upper heating zone, a lower heating zone, and a bottom heating zone.

[0010] The secondary purification device includes a second crucible held by a clamp connected to a separation block. The clamp controls the opening and closing of a copper clamp (a clamp with upper and lower lugs on the crucible) via the separation block, thus clamping and releasing the crucible. The copper clamp can conduct current when holding the crucible in place. After metal refining, the clamp is released to facilitate crucible removal. An inverter power supply and a step-down transformer are connected, and the output current of the step-down transformer is conducted to the second crucible through a copper plate.

[0011] Furthermore, the primary purification device uses a well-type resistance heating furnace to heat the first crucible.

[0012] Furthermore, the furnace temperature of both the upper heating zone and the lower heating zone is independently controlled by a PID controller.

[0013] Furthermore, one of the PID controllers is electrically connected to the upper heater of the upper heating zone, and the other PID controller is electrically connected to the lower heater of the lower heating zone.

[0014] Furthermore, both the upper heating zone and the lower heating zone are equipped with a first infrared thermometer.

[0015] Furthermore, a second infrared thermometer is provided outside the second crucible.

[0016] Furthermore, the first crucible is located in the primary refining furnace, and the second crucible is located in the secondary refining furnace.

[0017] Furthermore, the exterior of the first crucible is provided with a first high-temperature resistant heat insulation plate, a second high-temperature resistant heat insulation plate, and a third high-temperature resistant heat insulation plate from top to bottom.

[0018] Furthermore, the second crucible is provided with a support lug on its exterior, and the support lug is provided with a copper strip connection point.

[0019] Furthermore, an upper copper clamp and a lower copper clamp are respectively installed on the upper and lower parts of the support lug. The tightness between the upper copper plate and the lower copper plate and the crucible support lug is adjusted by adjusting the spring and fastening screw on the separation block using the operating rod.

[0020] Compared with the prior art, the metal refining apparatus provided by the present invention has the following beneficial effects:

[0021] The primary refining device of this invention uses a heating element instead of an electric furnace wire and adds a heating plate at the bottom of the furnace to improve the uniformity of metal heating and avoid short circuits caused by contact with the electric furnace wire. The secondary refining device is designed with a lug-type clamp to directly heat the cylinder. The heating current is controlled by controlling the heating duty cycle, resulting in more uniform material heating, low heating inertia, simple operation, convenient maintenance, and low operating costs.

[0022] This invention employs online infrared temperature measurement, featuring a compact probe, easy installation, strong anti-interference capability, good linearity, and a large distance coefficient ratio. It can measure confined spaces and improves the accuracy of temperature measurement.

[0023] This invention uses a PLC system to directly complete all data acquisition and temperature control of the heating process, providing basic data for process optimization.

[0024] The heating current of this invention is changed to a fixed adjustment, which can prevent the heating current from amplifying indefinitely, making the temperature control more precise and thus achieving a more perfect heating control effect. Attached Figure Description

[0025] To more clearly illustrate the technical solution of the present invention, the accompanying drawings used in the technical description will be briefly introduced below.

[0026] Figure 1 A schematic diagram of the heating process for the primary refining apparatus provided by this invention;

[0027] Figure 2 A schematic diagram of the heating process for the secondary refining apparatus provided by this invention;

[0028] Figure 3 A schematic diagram of the refining furnace provided for the present invention, showing the upper reinforcing ring;

[0029] Figure 4 A schematic diagram of the refining furnace provided for this invention shows the top cover;

[0030] Figure 5 A schematic diagram of the refining furnace provided by the present invention, showing the lower reinforcing ring;

[0031] Figure 6 A schematic diagram of the structure of a primary refining furnace with a built-in first crucible provided by the present invention;

[0032] Figure 7 A schematic diagram showing the arrangement of the second crucible lugs provided by the present invention;

[0033] Figure 8 A schematic diagram of the structure of the secondary refining furnace with a built-in second crucible provided by the present invention. Detailed Implementation

[0034] The following detailed description provides further details on specific implementation methods.

[0035] like Figures 1 to 8As shown, this invention provides a metal refining apparatus, including a primary purification device and a secondary purification device. The two refining devices are independent of each other. After refining in the primary device, the metal is transferred from the first crucible to the second crucible, where it continues to be purified. The primary refining device of this invention uses a heating element instead of an electric furnace wire and adds a heating plate to the furnace bottom, improving the uniformity of metal heating and preventing short circuits caused by contact with the electric furnace wire. The secondary refining device of this invention uses a lug-type clamp design to solve the key problem of contact overheating. It employs a medium-frequency, low-voltage, high-current heating method to directly heat the refining tank, resulting in more uniform material heating, lower heating inertia, and a voltage ≤5V, making heating safer.

[0036] like Figure 1 As shown, the primary purification unit uses a well-type resistance heating furnace to heat the first crucible 1, which is divided into three temperature zones from top to bottom: upper (upper heating zone 2), lower (lower heating zone 3), and bottom (bottom heating zone 4). The upper heating zone 2 and lower heating zone 3 are each independently temperature-controlled by a PID controller 6. The PID controller 6 is electrically connected to the upper heater of the upper heating zone 2, and another PID controller 6 is electrically connected to the lower heater of the lower heating zone 3. The bottom heater of the bottom heating zone 4 is located at the bottom of the titanium alloy crucible 1. First infrared thermometers 5 are installed in both the upper and lower heating zones. The heating element of the infrared thermometer 5 is made of quartz sand, ensuring uniform heating. The online infrared thermometer directly measures the crucible wall temperature through an opening in the furnace body.

[0037] Optionally, the first crucible 1 is a titanium alloy crucible. The original crucible was made of 316 stainless steel or nickel-chromium alloy, and the low-voltage output voltage of the transformer was about 5V. After the improvement, a titanium alloy crucible is used, and the final current is about 2500A, which meets the heating requirements.

[0038] like Figure 2 As shown, the secondary purification device uses a medium-frequency, low-voltage, high-current heating method to directly heat the crucible. The secondary purification device uses a high-power inverter 7 and a step-down transformer 8 to achieve low-voltage DC high current. The heating current is continuously controlled by the PLC through the medium-frequency inverter and the step-down transformer. The 380V power supply is converted into 500V, 1000Hz single-phase medium-frequency AC power supply by the inverter, stepped down to 5V by the medium-frequency low-voltage transformer, and rectified into a constant DC power supply of approximately 3000A.

[0039] Inverter 7 is connected to intermediate frequency step-down rectifier transformer 8, which is connected to a copper clamp. Inverter 7 converts 380V power into 500V 1000Hz single-phase intermediate frequency AC power. The intermediate frequency step-down transformer steps down the voltage to 5V and rectifies it into a constant DC power supply of approximately 3000A. Because high-current AC operation generates significant electromagnetic interference to surrounding electrical equipment, the intermediate frequency step-down rectifier transformer converts the AC power into DC power for heating the refining furnace, thus greatly reducing electromagnetic interference.

[0040] The clamp 10 is connected to the separator 11. The crucible 9 is located within the four clamps 10. The separator 11 controls the opening and closing of the copper plates (the copper plates are the upper and lower clamps of the crucible; clamping the crucible with the copper plates allows for current conduction, and releasing the clamps after metal refining facilitates crucible removal). When the upper operating lever 12 is tightened, the upper and lower copper plates of the clamps close, pressing the crucible lugs together. At this time, the current is conducted through the clamp 10 to the second crucible 9. An operating lever is located below the brake handle 12. The operating lever 12 controls the separator 11 to control the opening and closing of the copper plates.

[0041] After clamping the crucible support lugs with fixture 10, the circuit conducts electricity. The better the fit between the fixture and the crucible support lugs, the better the conductivity and the lower the possibility of local overheating at the contact points.

[0042] The temperature measured by the second infrared thermometer 13 on the furnace wall is transmitted to the PLC for real-time display. Based on the set temperature value, a continuous 4-20mA control signal is output to drive the power regulator for heating. To ensure that the equipment operates under high current conditions for a long time, a chiller and deionized water are used to circulate and cool the inverter power supply and transformer.

[0043] Optional. The second crucible 9 is a titanium alloy crucible.

[0044] It should be noted that the first crucible 1 has no lugs, while the second crucible 9 has lugs.

[0045] like Figures 3 to 5 As shown, the primary and secondary refining furnaces have the same external dimensions. Both furnaces are equipped with an upper reinforcing ring 14, a top cover 15, and a lower reinforcing ring 16, with the lower reinforcing ring 16 installed at the bottom. The upper reinforcing ring 14 is located at the top of the furnace, the top cover 15 is installed on the top of the furnace, and the lower reinforcing ring 16 is located at the bottom. The refining furnace, the first crucible, and the control system constitute the primary refining unit, with the first crucible placed inside the refining furnace.

[0046] like Figure 5 and Figure 6As shown, a titanium alloy crucible 1 is placed inside the primary refining furnace. From top to bottom, a first high-temperature resistant insulation plate 17, a second high-temperature resistant insulation plate 18, and a third high-temperature resistant insulation plate 19 are installed sequentially. A third infrared thermometer 20 is installed at the upper and lower parts of the primary refining furnace, respectively. Optionally, the furnace body 21 of the primary refining furnace is made of stainless steel.

[0047] The primary refining furnace uses a homogenizing block heating method, which has the advantages of simple heating control and can obtain a uniform heating temperature of the cylinder, which is conducive to the uniform melting of materials.

[0048] like Figure 7 and Figure 8 As shown, the secondary refining furnace has a second crucible 9 with two sets of supports attached to the top and bottom. The supports 29 have an overall structure that is approximately 1 / 4 circular. Each support 29 has a copper strip connection point 22. A copper plate clamp is installed at the corresponding position on the furnace body for each support. After the crucible with the supports is placed into the refining furnace, it is rotated 90 degrees, and the two sets (four) of supports 10 enter the corresponding two sets (four) of copper plate clamps. This method can reduce contact resistance.

[0049] The secondary dry refining crucible heating device of the present invention adds two sets of 1 / 4 circle lugs to the top and bottom of the crucible. After the crucible is placed in the heating furnace, it is rotated 90 degrees, and the lugs are respectively inserted into the four clamps. By tightening the brake handle, the upper and lower copper plates of the clamps close together, pressing the crucible lugs together. This method reduces contact resistance, and the current is conducted to the crucible through the clamps at both ends of the crucible, causing the crucible to heat up and transfer the heat to the metal.

[0050] like Figure 8 As shown, the upper part of the support 29 is equipped with an upper copper plate 23 and a lower copper plate 24, respectively. The tightness of the copper plates is adjusted by spring 25 and fastening screw 26. The furnace body 27 of the secondary refining furnace is made of stainless steel. The fourth infrared temperature probe 28 measures the temperature of the crucible wall from the side of the furnace body.

[0051] This invention employs a low-voltage, high-current heating method. Electrode clamps are installed at both ends of the refining crucible. After the clamps are tightened with support lugs, an adjustable low-voltage, high-current power supply is connected. The heating of the container achieves efficient metal heating, which is a key technical challenge and requires implementation through supporting equipment. The 380V power supply is converted to 500V, 1000Hz single-phase medium-frequency AC power by an inverter, then stepped down to 5V by a medium-frequency low-voltage transformer, and finally rectified into a constant maximum DC power supply of 7340A.

[0052] Therefore, in order to improve the uniformity of material heating and enhance the accuracy of temperature measurement during metal purification, this invention provides a novel heating method and a new type of furnace body that directly heats the refining crucible. The refining crucible has a uniform thickness and the heat output at each point is also equal, thus achieving uniform temperature control.

[0053] This invention utilizes a PLC system to directly complete all data acquisition and temperature control for the heating process. The power supply system for the primary and secondary refining crucible heating devices is equipped with a host computer monitoring system, allowing online monitoring of the equipment's operating status and providing temperature operating curves, thus offering fundamental data for process optimization. The heating control mode has also been improved from controlling the heating current to controlling the heating duty cycle. The heating current is now fixed and adjustable, preventing unlimited amplification and achieving a more perfect heating control effect.

[0054] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A metal refining apparatus, characterized in that, include: The first-stage purification device has a first crucible (1), and the first crucible (1) is provided with three temperature zones on the outside: an upper heating zone (2), a lower heating zone (3), and a bottom heating zone (4); The secondary purification device has a second crucible (9), which is held by a clamp (10). The clamp (10) is connected to a separation block (11). The clamp (10) controls the opening and closing of the copper clamp through the separation block (11). An inverter power supply (7) and a step-down transformer (8) are connected. The output current of the step-down transformer (8) is conducted to the second crucible (9) through a copper plate. The upper heating zone (2) and the lower heating zone (3) are both equipped with a first infrared thermometer (5). The second crucible (9) is equipped with a second infrared thermometer (13). The first crucible (1) is located in the first-stage refining furnace, and the second crucible (9) is located in the second-stage refining furnace. The first crucible (1) is provided with a first high-temperature resistant heat insulation plate (17), a second high-temperature resistant heat insulation plate (18), and a third high-temperature resistant heat insulation plate (19) from top to bottom. The second crucible (9) is provided with a support ear (29). The support ear (29) is provided with a copper strip connection point (22). The upper and lower parts of the support ear (29) are respectively equipped with an upper copper plate (23) and a lower copper plate (24). The spring (25) and the fastening screw (26) on the separation block are adjusted by the operating rod (12) to adjust the tightness between the upper copper plate (23) and the lower copper plate (24) and the crucible support ear.

2. The metal refining apparatus according to claim 1, characterized in that, The primary purification device uses a well-type resistance heating furnace to heat the first crucible (1).

3. The metal refining apparatus according to claim 1, characterized in that, The upper heating zone (2) and the lower heating zone (3) are both independently regulated by a PID controller (6) to control the furnace temperature.

4. The metal refining apparatus according to claim 3, characterized in that, One of the PID controllers (6) is electrically connected to the upper heater of the upper heating zone (2), and the other PID controller (6) is electrically connected to the lower heater of the lower heating zone (3).

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