Feeding device of system for continuously distilling and purifying crude indium

Abstract

The utility model relates to a feeding device of a system for continuously distilling and purifying crude indium, aiming at solving the problems of low efficiency, oxidation film pollution and impurity accumulation in the traditional batch distillation. The device comprises a distillation furnace, a raw material furnace and a material conveying pipe, seamless connection between normal pressure of the raw material furnace and vacuum of the distillation furnace is realized through a pressure difference self-driven feeding structure, and shutdown cooling is avoided. The bottom of the raw material furnace is provided with a suction groove, the top is additionally provided with a filter ring to intercept an oxide film in real time, micro-positive pressure protection is formed in cooperation with nitrogen purging, and non-metal impurities such as O and C are reduced. The double-circulation parallel mode enables the melting time of the raw material furnace and the working time of the distillation furnace to be overlapped, and the single-batch interval time is shortened. The design of conveying pipe heating and kettle body heat preservation reduces energy consumption, and a circulating water system is optimized to prolong the service life of the crucible. According to the device, the whole process of distillation-feeding-pretreatment is continuous, the purity of finished indium is high, the utilization rate of equipment is improved, and the device is suitable for the production field of high-purity indium such as semiconductors and ITO (Indium Tin Oxide) target materials.

Description

Technical Field

[0001] This utility model relates to the field of crude indium purification by distillation, and specifically to a feeding device for a continuous distillation purification system for crude indium. Background Technology

[0002] Currently, the industrial purification of crude indium (purity 97%-99.7%) mainly adopts the batch vacuum distillation method, which has the following core drawbacks:

[0003] Intermittent operation is inefficient: Each batch of distillation needs to go through the process of "heating-distillation-cooling-opening the lid to clean impurities-packing", and a single cycle takes 6-8 hours, of which cooling to a safe temperature (<150℃) takes 2.5-3 hours, resulting in insufficient equipment utilization.

[0004] Severe oxide film contamination: Traditional feeding methods require opening the lid, exposing the indium solution to the air and forming an oxide film, which enters the distillation furnace with the next batch of raw materials, resulting in a high content of non-metallic impurities in the finished indium, making it difficult to meet the requirements of 6N grade (99.9999%) high-purity indium.

[0005] Vicious cycle of impurity accumulation: Distillation residue (containing high-boiling-point impurities such as Fe and Cu) adheres to the furnace wall and requires manual or mechanical cleaning. The residual rate is >5%, which leads to an increase in the concentration gradient of impurities in subsequent batches and an increase in the total impurity content.

[0006] Limitations of existing technological improvement attempts:

[0007] While some semi-continuous feeding designs (such as alternating dual furnaces) shorten cooling time, they do not solve the problems of oxide film contamination and impurity accumulation, and significantly increase equipment complexity.

[0008] Traditional filtration devices rely on manual replacement of filters after shutdown, which cannot meet the needs of continuous production and has limited filtration efficiency. Utility Model Content

[0009] The present invention aims to overcome the shortcomings of the prior art and provide a feeding device for a continuous distillation purification system for crude indium.

[0010] The technical solution adopted in this utility model is as follows:

[0011] A feeding device for a continuous distillation purification system for crude indium includes: a distillation furnace, a raw material furnace, and a conveying pipe. One end of the conveying pipe is located at the bottom of the raw material furnace, and the other end is located inside the distillation furnace. A conveying valve is provided in the middle of the conveying pipe.

[0012] The raw material furnace includes a raw material crucible, a vessel body, and a vessel lid. The vessel body is fitted over the raw material crucible. The vessel lid is equipped with a vacuum pipeline and a nitrogen pipeline. The vessel body is equipped with a circulating water cooling system and a constant temperature heating system.

[0013] Furthermore, the circulating water cooling system is connected to the vessel lid, with the circulating water inlet and outlet located on the vessel lid.

[0014] Furthermore, a suction trough is provided at the bottom of the raw material crucible, and the end of the conveying pipe is located inside the suction trough.

[0015] Furthermore, a filter ring is provided at the top of the suction trough to filter out the indium oxide film, and the feed pipe passes through the filter ring.

[0016] Furthermore, control valves are installed in both the vacuum pipeline and the nitrogen pipeline.

[0017] Furthermore, the kettle lid is equipped with a pressure gauge for detecting the pressure inside the raw material furnace.

[0018] Furthermore, the feed pipe is equipped with a heating system, and the outer facade of the vessel is covered with an insulation layer.

[0019] In summary, due to the adoption of the above technical solution, the beneficial effects of this utility model are:

[0020] 1. Continuous production: Breaking through the limitations of batch operation, pressure difference self-driven feeding: Utilizing the pressure difference between the vacuum of the distillation furnace and the atmospheric pressure of the raw material furnace, feeding can be completed without the need for a pump, avoiding the intermittent process of traditional "cooling-opening-filling".

[0021] Dual-cycle time staggered operation: The raw material furnace chemicaling and the distillation furnace work in parallel, and the chemicaling time completely overlaps with the end of distillation (when 10% of indium solution remains), reducing the equipment idle time and realizing quasi-continuous production of "discharging and preparing materials at the same time".

[0022] 2. Purity Guarantee: Source interception of oxide film impurities, filter ring + nitrogen purging: The filter ring at the top of the suction tank intercepts the oxide film on the surface of the indium liquid in real time, and is combined with high-purity nitrogen micro-positive pressure purging to reduce the amount of oxide film brought in and reduce the content of non-metallic impurities.

[0023] Closed process: The raw material furnace is operated in a closed system throughout the entire process to avoid air contact, reduce the oxidation rate of indium liquid, and eliminate secondary pollution from the source.

[0024] 3. Efficiency Improvement: Automated Sewage Discharge: The oxide film is periodically discharged through the bottom sewage outlet, eliminating the need for manual furnace cleaning.

[0025] 4. Simplified operation: Pressure / temperature closed-loop control: The pressure gauge monitors the raw material furnace pressure in real time and automatically switches between vacuum / nitrogen modes; reducing the frequency of manual intervention. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the overall structure of this utility model.

[0027] Marked in the image:

[0028] 1-Distillation furnace, 2-Raw material furnace, 3-Feeding pipe, 4-Feeding valve, 5-Raw material crucible, 6-Cabin body, 7-Cabin lid, 8-Vacuum pipeline, 9-Nitrogen pipeline, 10-Circulating water cooling system, 11-Constant temperature heating system, 12-Feeding trough, 13-Filter ring, 14-Control valve, 15-Pressure gauge, 16-Insulation layer, 17-Heating system. Detailed Implementation

[0029] The present invention will now be described in detail with reference to the accompanying drawings.

[0030] To make the objectives, technical solutions, and advantages of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this utility model and are not intended to limit this utility model.

[0031] Example 1

[0032] In this embodiment, as Figure 1 As shown, a feeding device for a continuous distillation purification system for crude indium includes: a distillation furnace, a raw material furnace, and a conveying pipe. One end of the conveying pipe is located at the bottom of the raw material furnace, and the other end is located inside the distillation furnace. A conveying valve is provided in the middle of the conveying pipe.

[0033] The raw material furnace includes a raw material crucible, a vessel body, and a vessel lid. The vessel body is fitted over the raw material crucible. The vessel lid is equipped with a vacuum pipeline and a nitrogen pipeline. The vessel body is equipped with a circulating water cooling system and a constant temperature heating system.

[0034] Specifically: the distillation furnace (horizontal cylindrical shape, graphite lining) and the raw material furnace (vertical cylindrical shape, stainless steel vessel body) are connected by a φ60mm feed pipe, and the feed valve is a pneumatic ball valve.

[0035] The bottom suction trough of the raw material furnace (50mm deep, 15° inclination) and the end of the conveying pipe (10mm from the bottom of the trough) form a "liquid seal" to prevent the vacuum of the distillation furnace from drawing back air.

[0036] By utilizing the pressure difference between the vacuum of the distillation furnace and the atmospheric pressure of the raw material furnace, the indium liquid can flow by gravity without the need for a pump, thus avoiding batch cooling shutdowns.

[0037] Furthermore, the circulating water cooling system is connected to the vessel lid, with the circulating water inlet and outlet located on the vessel lid.

[0038] The lid integrates a spiral cooling water channel, which is injected from the top to prevent the high-temperature zone at the bottom of the crucible from cracking due to sudden cooling.

[0039] Cooling water is applied evenly from the top, extending the crucible's lifespan.

[0040] Furthermore, a suction trough is provided at the bottom of the raw material crucible, and the end of the conveying pipe is located inside the suction trough.

[0041] The bottom suction trough of the raw material crucible is inverted conical, and three sets of guide fins are set in the trough to promote the accumulation of indium liquid in the feed pipe.

[0042] Four side holes are machined at the end of the feed pipe to prevent residue from being sucked into the bottom of the tank.

[0043] The suction trough reduces raw material waste and indirectly improves purity.

[0044] Furthermore, a filter ring is provided at the top of the suction trough to filter out the indium oxide film, and the feed pipe passes through the filter ring.

[0045] The filter ring is made of sintered stainless steel mesh and is nested at the top of the suction trough, with the feed pipe passing through the center.

[0046] During feeding, the indium solution passes through the filter ring, and the oxide film is intercepted in the tank, thus intercepting impurities in the oxide film at the source and improving purity.

[0047] Furthermore, control valves are installed in both the vacuum pipeline and the nitrogen pipeline.

[0048] The vacuum line is equipped with a solenoid ball valve, and the nitrogen line is equipped with a pneumatic regulating valve, which are interlocked with the feed valve.

[0049] Before feeding: the vacuum valve is fully opened, and a vacuum is created within 30 seconds; during feeding: the nitrogen valve is opened to maintain a slight positive pressure in the raw material furnace. This prevents air backflow during feeding, which would reduce the oxidation rate of the indium solution.

[0050] Furthermore, the kettle lid is equipped with a pressure gauge for detecting the pressure inside the raw material furnace.

[0051] A digital pressure gauge is installed on the vessel lid and linked to the PLC: when the pressure is >0.12MPa, the pressure relief valve opens automatically; when the pressure is <0.08MPa, nitrogen is added.

[0052] Pressure fluctuations are controlled within ±5 kPa to prevent indium liquid from splashing due to excessively fast material feeding, thus ensuring operational safety.

[0053] Furthermore, the feed pipe is equipped with a heating system, and the outer facade of the vessel is covered with an insulation layer.

[0054] The feed pipe is covered with a silicone heating tape, and the reactor body insulation layer is made of rock wool and an aluminum foil reflective layer. The heat loss of the feed pipe is less than 5%, the surface temperature of the reactor body is ≤60℃, and the energy consumption is reduced compared with the traditional process.

[0055] Example 2:

[0056] A method for using a feeding device for a continuous distillation purification system for crude indium includes the following steps:

[0057] S1: Open the lid of the reactor, put the indium raw material into the raw material crucible, and close the lid of the reactor.

[0058] The raw material furnace lid is opened manually, and the crude indium block is slid in along the inner wall of the raw material crucible to avoid impacting the bottom suction trough.

[0059] When the lid is closed, the sealing ring automatically engages with the groove in the vessel body, and pressure is applied evenly by four sets of bolts to ensure airtightness.

[0060] Device features: The vessel lid integrates vacuum and nitrogen pipelines, and the pressure gauge displays the initial atmospheric pressure in real time.

[0061] S2: After starting the circulating water cooling system, turn on the vacuum system to continuously evacuate the vacuum.

[0062] Start the circulating water system, and cool water is injected from the spiral channel at the top of the kettle lid, which lowers the outer wall of the raw material crucible within 3 minutes.

[0063] Simultaneously, the vacuum valve is opened, and the mechanical pump + molecular pump assembly pumps air. After 10 minutes, the pressure gauge shows -0.095MPa (close to the ultimate vacuum).

[0064] Equipment configuration: The circulating water inlet and outlet are located on the vessel lid to prevent cooling water from directly rinsing the high-temperature crucible.

[0065] S3: Turn on the constant temperature heating system of the reactor body to start melting the material, and at the same time turn on the heating system of the conveying pipe body;

[0066] Turn on the constant temperature heating of the vessel (electromagnetic induction heating), and raise it to 430℃ within 30 minutes (the indium liquid is completely melted and the surface is mirror-like).

[0067] The heating system of the feed pipe is started simultaneously (heating cable 380℃), and the temperature in the middle of the pipe is detected by an infrared thermometer to reach 350℃ to prevent indium liquid from condensing.

[0068] Maintain a vacuum during the indium melting process to prevent oxidation of the indium solution. Any sporadic oxide films that may appear on the surface of the liquid are intercepted by subsequent filter rings.

[0069] S4: After the material is melted, turn off the vacuum system and introduce high-purity argon gas into the reactor until the pressure reaches atmospheric pressure;

[0070] Close the vacuum valve, slowly open the nitrogen valve, observe the pressure gauge until it reaches 0.1 MPa (atmospheric pressure), and maintain this pressure for 30 seconds to purge any residual air from the vessel.

[0071] At this time, the raw material furnace is in a state of "slight positive pressure + liquid indium", which creates pressure differential conditions for the S5 self-driven feeding.

[0072] S5: After the previous batch of indium raw material in the distillation furnace is distilled, open the feed valve. At this time, the distillation furnace is in a vacuum state and the pressure inside the vessel is normal. The raw material is sucked into the main furnace through the feed pipe.

[0073] Confirm the vacuum level of the distillation furnace (via the pipeline pressure sensor), and open the feed valve (pneumatic ball valve, rotate 90° to open).

[0074] The indium liquid is drawn into the feed pipe by pressure difference, and then converges through the guide fins of the suction tank, forming a stable liquid flow within 30 seconds.

[0075] Device association: The end of the conveying pipe is 10mm away from the bottom of the suction tank to avoid sucking in high-boiling-point impurities that have settled at the bottom of the tank.

[0076] S6: After feeding, close the conveying valve and the reactor body heating, turn on the vacuum system, and turn off the pipeline heating after half an hour; after the overall temperature drops, turn off the vacuum system and wait for the next feeding.

[0077] Once feeding is complete, close the feed valve and immediately restart the raw material furnace vacuum system. After heating the feed pipe for 10 minutes, close it and use the residual heat (>300℃) to purge any remaining indium solution to prevent solidification and blockage.

[0078] The insulated layer of the reactor body maintains the residual heat of the raw material furnace at 150°C, storing heat for rapid heating of the next batch.

[0079] Furthermore, during the S5 feeding process, raw material pretreatment is performed simultaneously, specifically including:

[0080] When the feed valve is opened, the circulating water cooling system of the raw material furnace cools down to 150-200℃, and at the same time, high-purity nitrogen is introduced through the nitrogen pipeline to purge the surface of the raw material crucible.

[0081] At the same time as the feed valve is opened, the circulating water system increases the flow rate (8L / min) to reduce the temperature of the raw material crucible from 430℃ to 180℃ within 5 minutes (to avoid long-term exposure of high-temperature indium liquid).

[0082] Nitrogen gas is introduced through the lid of the vessel, and the gas flow spirals downwards along the inner wall of the crucible, forming a "gas curtain" above the liquid surface to inhibit oxidation.

[0083] After each of the three feeding cycles, the bottom drain valve of the reactor is manually opened to discharge the oxide film residue using the residual nitrogen pressure.

[0084] Furthermore, a dual-loop parallel mode is adopted to improve continuity, specifically including:

[0085] When the remaining indium solution in the distillation furnace is ≤10% of the raw material amount, the raw material furnace starts S3 for material preparation. At this time, the distillation furnace still maintains vacuum distillation. After the previous batch of distillation is completed, S5 feeding is immediately executed.

[0086] Distillation furnace: 0-5.5h (main distillation stage, 1120℃) → 5.5-6h (10% indium solution remaining, maintain vacuum) → 6-6.1h (receive feed).

[0087] Raw material furnace: 4.5-5.5h (start S3 material processing in advance, melt and clear at 430℃) → 5.5-6h (wait for distillation furnace signal) → 6-6.1h (execute S5 feeding).

[0088] Triggering condition: When the weighing sensor of the distillation furnace detects that the remaining indium solution is <10kg (preset by PLC), it automatically sends a "prepare to process" signal to the raw material furnace.

[0089] The above description is only a preferred embodiment of the utility model and is not intended to limit the utility model. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the utility model should be included within the protection scope of the utility model.

Claims

1. A feeding device for a continuous distillation purification system for crude indium, characterized in that: include: The distillation furnace, the raw material furnace, and the conveying pipe are provided. One end of the conveying pipe is located at the bottom of the raw material furnace, and the other end is located inside the distillation furnace. A conveying valve is provided in the middle of the conveying pipe. The raw material furnace includes a raw material crucible, a vessel body, and a vessel lid. The vessel body is fitted over the raw material crucible. The vessel lid is equipped with a vacuum pipeline and a nitrogen pipeline. The vessel body is equipped with a circulating water cooling system and a constant temperature heating system.

2. The feeding device for a continuous distillation purification system for crude indium according to claim 1, characterized in that: The circulating water cooling system is connected to the vessel lid, and the inlet and outlet of the circulating water cooling system are located on the vessel lid.

3. The feeding device for a continuous distillation purification system for crude indium according to claim 1, characterized in that: The bottom of the raw material crucible is provided with a suction groove, and the end of the conveying pipe is located inside the suction groove.

4. The feeding device for a continuous distillation purification system for crude indium according to claim 3, characterized in that: The top of the suction trough is equipped with a filter ring for filtering and isolating the indium oxide film, and the feed pipe passes through the filter ring.

5. The feeding device for a continuous distillation purification system for crude indium according to claim 1, characterized in that: Both the vacuum pipeline and the nitrogen pipeline are equipped with control valves.

6. The feeding device for a continuous distillation purification system for crude indium according to claim 1, characterized in that: The kettle lid is equipped with a pressure gauge for detecting the pressure inside the raw material furnace.

7. The feeding device for a continuous distillation purification system for crude indium according to claim 1, characterized in that: The feed pipe is equipped with a heating system.

8. The feeding device for a continuous distillation purification system for crude indium according to claim 1, characterized in that: The outer facade of the vessel is provided with a heat insulation layer.

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