Efficient recovery method and device for bismuth telluride waste based on filtering synthesis

Abstract

The invention provides an efficient recovery method and device for bismuth telluride waste based on filtration synthesis, and the method comprises the following steps: 1, material pretreatment: putting the bismuth telluride waste into a cleaning tank, controlling the ultrasonic cleaning time at 5-10 min, taking out the material, rinsing with deionized water, and then carrying out vacuum drying to remove surface moisture; step 2, filtering and synthesizing: putting the dried bismuth telluride waste into a filtering crucible with a microporous structure, putting the filtering crucible into a synthetic furnace, vacuumizing, introducing hydrogen-argon mixed gas as protective gas, and controlling the pressure in the furnace to be 0.01-0.1 MPa; step 3, heating and melting: heating the synthetic furnace to 700-800 DEG C at a heating rate of 5-15 DEG C / min, and keeping the temperature for 3-5 hours, so that the bismuth telluride waste is fully melted and flows into the discharging crucible through the microporous structure; and 4, cooling and curing: cooling to room temperature along with the furnace, and forming the synthesized bismuth telluride material into a cylindrical blank.

Description

Technical Field

[0001] The present invention relates to the field of thermoelectric materials, and particularly to a method and device for efficiently recycling bismuth telluride waste based on filtration synthesis. Background Art

[0002] Bismuth telluride (Bi2Te3) is a semiconductor material widely used in thermoelectric conversion, with good thermoelectric properties, and is used in thermoelectric power generation and refrigeration devices. However, during the manufacturing and processing of bismuth telluride materials, a large amount of waste is usually generated, especially the head and tail materials of the ingot, and these materials still have high thermoelectric conversion potential. The traditional recycling methods mainly adopt high-temperature melting synthesis processes, but there are the following technical problems:

[0003] Serious material loss: In the traditional process, the recycled materials need to be melted. Due to high-temperature oxidation and material loss during the melting process, the recovery rate is usually less than 80%.

[0004] Tube cracking problem: The existing process mainly relies on quartz melting tubes for material melting. During the cooling process, the quartz tubes are prone to tube cracking, resulting in material loss and affecting the recovery efficiency.

[0005] Limited product purity: The recycled bismuth telluride materials often have reduced purity due to impurity contamination, making their thermoelectric properties inferior to those of the original materials.

[0006] Environmental pollution and safety hazards: Steps such as pickling and sealing increase the danger of the production process, and at the same time generate a large amount of waste acid solution, which is not friendly to the environment.

[0007] In order to improve the recovery efficiency of bismuth telluride waste and optimize the synthesis quality, it is necessary to develop a more efficient, safe and environmentally friendly recovery synthesis process to meet the needs of industrial applications. Summary of the Invention

[0008] Aiming at the problems existing in the prior art, the present invention provides a method and device for efficiently recycling bismuth telluride waste based on filtration synthesis to solve the problems of the prior art.

[0009] The technical solution of the present invention is: A method for efficiently recycling bismuth telluride waste based on filtration synthesis, characterized by comprising:

[0010] Step 1, material pretreatment: Place the bismuth telluride waste into a cleaning tank, control the ultrasonic cleaning time at 5 - 10 minutes, take out the material, rinse it with deionized water, and then perform vacuum drying to remove surface moisture;

[0011] Step 2: Filtering and synthesis. Place the dried bismuth telluride waste in a filtering crucible with a microporous structure. The filtering crucible is placed in a synthesis furnace. After evacuating the air, introduce a hydrogen-argon mixed gas as a protective atmosphere, and control the pressure in the furnace at 0.01 - 0.1 MPa.

[0012] Step 3: Heating and melting. Heat the synthesis furnace at a heating rate of 5 - 15 °C / min to 700 - 800 °C, and keep it warm for 3 - 5 h, so that the bismuth telluride waste is fully melted and flows into the discharge crucible through the microporous structure.

[0013] Step 4: Cooling and solidifying. Cool down to room temperature with the furnace. After this process, the synthesized bismuth telluride material forms a cylindrical blank.

[0014] Through process optimization, the present invention significantly improves the material recovery rate and purity, while reducing environmental pollution and potential production safety hazards. The use of filtering synthesis technology replaces the traditional smelting process, avoiding material loss caused by the cracking of the quartz smelting tube and improving the material recovery rate. The use of ultrasonic cleaning instead of the traditional pickling method effectively removes impurities on the material surface, increasing the purity of the recycled material to 99%. It reduces environmental pollution in the pickling process, decreases equipment corrosion, and improves production safety. Optimize the synthesis environment to reduce the formation of oxides. Introduce a hydrogen-argon mixed gas into the synthesis furnace, and effectively remove the oxides generated during the synthesis process through redox reactions, improving the purity and mechanical strength of the material. Make the surface of the final material smoother and cleaner, and improve its thermoelectric performance.

[0015] Further preferably, the filtering crucible is a graphite crucible with micropores at the bottom, and the pore diameter is 0.1 - 1 cm. Using a high-purity graphite crucible makes the synthesis process more stable and improves product consistency.

[0016] Further preferably, in Step 1, an ultrasonic cleaner is used for cleaning, and the frequency of the ultrasonic cleaner is 10 - 100 kHz, and the cleaning time is 5 - 10 min.

[0017] Further preferably, in Step 1, the temperature of vacuum drying is 80 - 100 °C, and the time of vacuum drying is 10 - 40 min to remove surface moisture.

[0018] Further preferably, the maximum heating temperature of the synthesis furnace is 1000 - 1300 °C.

[0019] Further preferably, the hydrogen content in the hydrogen-argon mixed gas is 5% - 10%, and the argon content is 90% - 95%. As a protective gas, it prevents material oxidation.

[0020] A bismuth telluride waste recycling device based on filtering synthesis, characterized by comprising:

[0021] A synthesis furnace is internally provided with a filtering crucible and a discharging crucible. The bottom of the filtering crucible has a microporous structure for the molten bismuth telluride waste to flow into and out of the discharging crucible.

[0022] A gas control system is used to introduce a hydrogen-argon mixed gas into the synthesis furnace and control the pressure inside the furnace.

[0023] A heating control system is used to control the heating rate and holding time of the synthesis furnace. Specific embodiments

[0024] The present invention will be further described below in conjunction with embodiments.

[0025] Embodiment 1, A method for efficient recovery of bismuth telluride waste based on filtration synthesis, including: Step 1, material pretreatment. Place the bismuth telluride waste into a cleaning tank, control the ultrasonic cleaning time at 5 - 10 minutes, take out the material, rinse it with deionized water, and then perform vacuum drying to remove surface moisture. Step 2, filtration synthesis. Place the dried bismuth telluride waste into a filtering crucible with a microporous structure. The filtering crucible is placed inside the synthesis furnace. After evacuating, introduce a hydrogen-argon mixed gas as a protective atmosphere, and control the pressure inside the furnace at 0.01 - 0.1 MPa. Step 3, heating and melting. Heat the synthesis furnace at a heating rate of 5 - 15 °C / min to 700 - 800 °C, and hold for 3 - 5 hours to fully melt the bismuth telluride waste and allow it to flow into the discharging crucible through the microporous structure. Step 4, cooling and solidifying. Cool down to room temperature with the furnace. After this process, the synthesized bismuth telluride material forms a cylindrical blank.

[0026] The present invention significantly improves the material recovery rate and purity through process optimization, while reducing environmental pollution and potential production safety hazards. The use of filtration synthesis technology instead of traditional smelting processes avoids material loss caused by cracked quartz smelting tubes and improves the material recovery rate. The use of ultrasonic cleaning instead of traditional pickling methods effectively removes impurities on the material surface and increases the purity of the recovered material to 99%. It reduces environmental pollution in the pickling process, reduces equipment corrosion, and improves production safety. Optimizing the synthesis environment reduces the formation of oxides. Introducing a hydrogen-argon mixed gas into the synthesis furnace effectively removes oxides generated during the synthesis process through redox reactions, improving the purity and mechanical strength of the material. This makes the surface of the final material smoother and cleaner and improves its thermoelectric performance.

[0027] Further preferably, the filtering crucible is a graphite crucible, and the bottom of the graphite crucible is provided with micropores with a pore diameter of 0.1 - 1 cm. Using a high-purity graphite crucible makes the synthesis process more stable and improves product consistency.

[0028] Further preferably, in step one, an ultrasonic cleaning machine is used for cleaning, and the frequency of the ultrasonic cleaning machine is 10 - 100 kHz, and the cleaning time is 5 - 10 min.

[0029] Further preferably, in step one, the temperature of vacuum drying is 80 - 100 °C, and the time of vacuum drying is 10 - 40 min, so as to remove surface moisture.

[0030] Further preferably, the maximum heating temperature of the synthesis furnace is 1000 - 1300 °C.

[0031] Further preferably, the hydrogen content in the hydrogen - argon mixed gas is 5% - 10%, and the argon content is 90% - 95%. As a protective gas, it can prevent material oxidation.

[0032] A bismuth telluride waste recycling device based on filtration synthesis includes: a synthesis furnace, which is internally provided with a filtration crucible and a discharging crucible. The bottom of the filtration crucible has a microporous structure for the molten bismuth telluride waste to flow into the discharging crucible; a gas control system for introducing a hydrogen - argon mixed gas into the synthesis furnace and controlling the pressure in the furnace; a heating control system for controlling the heating rate and holding time of the synthesis furnace.

[0033] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. An efficient recovery method for bismuth telluride waste based on filtration synthesis, characterized in that, Including: Step 1, material pretreatment: Place the bismuth telluride waste in a cleaning tank, control the ultrasonic cleaning time at 5 - 10 min, take out the material, rinse it with deionized water, and then conduct vacuum drying to remove surface moisture; Step 2, filtration synthesis: Place the dried bismuth telluride waste in a filtration crucible with a microporous structure. The filtration crucible is placed in a synthesis furnace. After evacuating, introduce a hydrogen - argon mixed gas as a protective gas, and control the pressure in the furnace at 0.01 - 0.1 MPa; Step 3, heating and melting: Heat the synthesis furnace at a heating rate of 5 - 15 °C / min to 700 - 800 °C, and keep it warm for 3 - 5 h to fully melt the bismuth telluride waste and allow it to flow into the discharge crucible through the microporous structure; Step 4, cooling and solidifying: Cool the furnace to room temperature. After this process, the synthesized bismuth telluride material forms a cylindrical blank.

2. The high-efficiency recovery method and device for bismuth telluride waste based on filtration synthesis according to claim 1, wherein, The filtration crucible is a graphite crucible, and the bottom of the graphite crucible is provided with micropores, and the pore diameter is 0.1 - 1 cm.

3. The high-efficiency recovery method and device for bismuth telluride waste based on filtration synthesis according to claim 1, wherein In step 1, an ultrasonic cleaner is used for cleaning, and the frequency of the ultrasonic cleaner is 10 - 100 kHz, and the cleaning time is 5 - 10 min.

4. The high-efficiency recovery method and device for bismuth telluride waste based on filtration synthesis according to claim 1, characterized in that, In step 1, the temperature of vacuum drying is 80 - 100 °C, and the time of vacuum drying is 10 - 40 min.

5. A method and device for efficient recovery of bismuth telluride waste based on filtration synthesis according to claim 1, characterized in that The maximum heating temperature of the synthesis furnace is 1000 - 1300 °C.

6. The high-efficiency recovery method and device for bismuth telluride waste based on filtration synthesis according to claim 1, characterized in that The hydrogen content in the hydrogen - argon mixed gas is 5% - 10%, and the argon content is 90% - 95%.

7. A tellurium bismuth waste recycling device based on filtration synthesis, characterized in that, Including: A synthesis furnace, internally provided with a filtration crucible and a discharge crucible. The bottom of the filtration crucible has a microporous structure for the molten bismuth telluride waste to flow into the discharge crucible; A gas control system for introducing a hydrogen - argon mixed gas into the synthesis furnace and controlling the pressure in the furnace; A heating control system for controlling the heating rate and holding time of the synthesis furnace.