Combined treatment tower and combined treatment method for rare earth dust flue gas

Abstract

The invention discloses a combined treatment method for rare earth dust and flue gas, and relates to a rare earth processing technology, the method comprises the following steps: cooling discharged dust and flue gas mixed gas to reach a preset initial temperature, and then carrying out dust removal treatment on the discharged dust and flue gas mixed gas through an electrostatic adsorption device at a set initial airflow speed to obtain flue gas; detecting the dust content in the flue gas, and if the dust content is greater than or equal to a set target threshold value, dynamically adjusting the temperature and the airflow speed of dust and flue gas mixed gas according to the dust content; when the airflow velocity of the dust and smoke mixed gas is adjusted, the real-time flow of the smoke and the initial flow of the smoke when the dust and smoke mixed gas is at the initial airflow velocity are obtained, and the spraying flow in the spraying tower is corrected according to the real-time flow and the initial flow. The invention further discloses a combined treatment tower for the rare earth dust flue gas. The dust removal rate of dust and smoke mixed gas is higher, and the recovery rate of rare earth dust is increased.

Description

Technical Field

[0001] The present invention relates to a rare earth processing technology, and more specifically, it relates to a combined treatment tower and a combined treatment method for rare earth dust flue gas. Background Art

[0002] Rare earth, as a strategic resource, the rare earth elements contained therein are widely used in high-tech fields. At present, the smelting of rare earth metals usually adopts the fluoride molten salt electrolysis process, and a large amount of harmful flue gas will be generated along with the electrolysis process. In addition, the electrolyzed rare earth is generally rare earth powder. During this process, the boiling of the electrolyte will cause some rare earth powder to break away from the electrolyte and become rare earth dust, which is sucked out of the electrolytic cell together with the flue gas through the exhaust port. Since the value of rare earth powder is relatively high, it is necessary to recover these sucked-out rare earth dust.

[0003] For the treatment process of the dust-smoke mixed gas sucked out from the electrolytic cell, generally, while chemically treating the harmful part in the flue gas with a solution, the rare earth dust in the dust-smoke mixed gas is sedimented and recovered. The treated flue gas will be discharged into the atmosphere, and the sedimented rare earth dust will be recovered through precipitation. Therefore, the recovered rare earth dust is actually a mixture of dust and solution. To avoid the influence of these solutions on the dust and the environment, it is also necessary to wash and remove them with water. However, such a method not only makes the rare earth dust vulnerable to secondary pollution, but also increases the treatment cycle and reduces the recovery rate of rare earth dust.

[0004] Therefore, related technologies have proposed dust removal through the action of electrostatic adsorption. That is, an electrostatic adsorption device is added in front of the spray tower, and the dust collection plate of the electrostatic adsorption device adsorbs the rare earth dust, so as to recover the rare earth dust and achieve dry-wet separation. However, it is found through experiments that although the electrostatic adsorption method can recover rare earth dust, its recovery rate is usually about 70%-80%, which is still not ideal. Therefore, it needs to be improved. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a combined treatment tower and a combined treatment method for rare earth dust flue gas in view of the deficiencies of the prior art.

[0006] A combined treatment method for rare earth dust flue gas according to the present invention is as follows: the discharged dust-smoke mixed gas is cooled to reach a preset initial temperature, and then passes through an electrostatic adsorption device at a set initial gas flow rate for dust removal treatment to obtain flue gas; the dust content in the flue gas is detected, and if the dust content is greater than or equal to a set target threshold, the temperature and gas flow rate of the dust-smoke mixed gas are dynamically adjusted according to the dust content;

[0007] When the air flow velocity of the dust-laden flue gas mixture is adjusted, obtain the real-time flow rate of the flue gas and the initial flow rate of the flue gas when the dust-laden flue gas mixture is at the initial air flow velocity, and correct the spray flow rate in the spray tower according to the real-time flow rate and the initial flow rate.

[0008] Preferably, the method for dynamically adjusting the temperature and air flow velocity of the dust-laden flue gas mixture according to the initial dust content is as follows:

[0009] First step: When the dust content is greater than or equal to the target threshold, reduce the initial air flow velocity of the dust-laden flue gas mixture by a set velocity step to obtain a new air flow velocity, and calculate the new temperature;

[0010] Second step: The dust-laden flue gas mixture passes through the electrostatic adsorption device at the new air flow velocity and new temperature;

[0011] Third step: Collect the dust content corresponding to the new air flow velocity and new temperature of the dust-laden flue gas mixture to obtain a new dust content; if the new dust content is less than the target threshold, the dust-laden flue gas mixture is transported at the current temperature and velocity; if the new dust content is greater than or equal to the target threshold, perform the first step and count the loop value at the same time; if the loop value count is equal to N, perform the fourth step;

[0012] Fourth step: Replace the dust collecting electrode of the electrostatic adsorption device with a new dust collecting electrode, and at the same time set the current temperature and air flow velocity of the dust-laden flue gas mixture to the initial temperature and initial air flow velocity respectively.

[0013] Preferably, the calculation formula for the new temperature is:

[0014] Tn = T0 * Vn / V0;

[0015] In the formula, Tn is the new temperature; T0 is the initial temperature; Vn is the new air flow velocity, n is from 1 to N; V0 is the initial air flow temperature.

[0016] Preferably, the initial temperature is 150 - 200 °C.

[0017] Preferably, the method for correcting the spray flow rate is:

[0018] Use the comparison value between the real-time flow rate and the initial flow rate as the correction coefficient, calibrate the initial flow rate of the spray head according to the initial flow rate, and calculate the spray flow rate by multiplying the initial flow rate by the correction coefficient.

[0019] A combined treatment tower for rare earth dust flue gas, comprising a dust removal tower, a first spray tower, a second spray tower, a third spray tower and an industrial control computer connected in sequence. An electrostatic adsorption device is installed in the dust removal tower. The air inlet of the dust removal tower is connected to a gas pre-storage tower. A temperature sensor is installed in the gas pre-storage tower. A cooling device is installed on the pipeline between the gas pre-storage tower and the dust suction port. A dust detector and a gas flow detector are installed at the air outlet of the dust removal tower;

[0020] The industrial control computer is used to receive the electrical signals of the temperature sensor, the dust detector and the gas flow detector, and control the electrostatic adsorption device and the spray heads in the spray tower to work according to the electrical signals, so as to realize the dust removal of the dust and smoke mixed gas and the spray treatment of the flue gas.

[0021] Preferably, the electrostatic adsorption device includes a discharge electrode and a dust collecting electrode; the discharge electrode is fixedly installed in the dust removal tower, the discharge electrode is of a hollow structure, the dust collecting electrode is located in the discharge electrode, and a contact electrode connected in contact with the dust collecting electrode is installed on the inner side of the top of the dust removal tower; a driving component is installed above the dust removal tower, and the driving end of the driving component penetrates the dust removal tower and is detachably connected to the dust collecting electrode; a turntable is installed below the dust removal tower, a plurality of collection buckets are arranged on the turntable, a discharge port is arranged at the bottom of the dust removal tower, a valve is installed in the discharge port, and the discharge port corresponds to the collection bucket located below it.

[0022] Preferably, the driving component includes a hydraulic cylinder, a hollow outer shaft, an inner rotating shaft and a motor; the hydraulic cylinder is installed above the dust removal tower, and the hollow outer shaft is fixedly installed on one side of the piston rod of the hydraulic cylinder; the dust collecting electrode is of a hollow structure, and an insulating closing plate is fixed at the bottom port of the dust collecting electrode. A hexagonal positioning groove is opened at the bottom of the collection bucket, and a hexagonal head matching the hexagonal positioning groove is arranged below the insulating closing plate; the hollow outer shaft penetrates the top of the dust removal tower and extends into the dust collecting electrode, the motor is fixedly installed on the top of the hollow outer shaft, the inner rotating shaft is fixed at the output end of the motor, the inner rotating shaft extends along the hollow outer shaft to the other end thereof, a screw rod is arranged at one end of the inner rotating shaft extending to the end of the hollow outer shaft, the screw rod is connected to the inner rotating shaft through an elastic positioning structure, and a nut is fixed on the insulating closing plate, and the screw rod is screwed into the nut.

[0023] Preferably, the elastic positioning structure includes a spring and a hexagonal shaft; a hexagonal groove is opened at the end of the inner rotating shaft, the spring is placed in the hexagonal groove, the hexagonal shaft is movably inserted into the hexagonal groove and contacts the spring, and the screw rod is fixedly installed at the end of the hexagonal shaft.

[0024] Preferably, a threaded hole is provided at the notch of the hexagonal groove, a positioning ring is screwed in the threaded hole, the inner diameter of the positioning ring is smaller than the outer diameter of the hexagonal shaft, and a cylindrical section is provided at the connection between the hexagonal shaft and the screw rod, and the cylindrical section is movably inserted into the positioning ring.

[0025] Advantageous effects

[0026] The advantages of the present invention are as follows:

[0027] 1. During the process of electrostatic adsorption dust removal of the dust and smoke mixed gas in the dust removal tower, the temperature and air flow velocity of the dust and smoke mixed gas are adjusted according to the dust content in the flue gas discharged from the dust removal tower, so that it can better remove dust, and the dust removal rate of the dust and smoke mixed gas is higher, thereby improving the recovery rate of rare earth dust. The flue gas after dust removal directly enters the spray tower for harmful component treatment, thus improving the treatment efficiency of the combined treatment tower.

[0028] 2. The present invention provides a collector replacement technology. When it is impossible to meet the dust content requirement after adjusting the temperature and gas flow velocity of the dust and smoke mixed gas, the replacement of the dust collector electrode and the recovery of the adsorbed rare earth dust are realized through the cooperation of the driving component, the turntable and the collection bucket, and a new dust collector electrode is replaced, solving the problem that the adsorption effect is affected due to too much dust adsorbed on the dust collector electrode.

[0029] 3. During the process of adjusting the air flow velocity of the dust and smoke mixed gas, since the reduction of the air flow velocity results in the reduction of the flue gas volume, in order to make the spray flow rate match the outlet gas volume of the flue gas, the present invention corrects the spray flow rate, thereby achieving the purpose of saving energy consumption. Description of the drawings

[0030] Figure 1 It is a schematic diagram of the combined treatment tower of the present invention;

[0031] Figure 2 It is a schematic diagram of the internal structure of the dust removal tower of the present invention (the dust collector electrode is located in the collection bucket);

[0032] Figure 3 It is Figure 2 The enlarged structural schematic diagram at A in

[0033] Figure 4 It is a schematic diagram of the internal structure of the dust removal tower of the present invention (the dust collector electrode is located in the dust removal tower).

[0034] Wherein: 1 - cooling device, 2 - gas pre-storage tower, 3 - dust removal tower, 4 - first spray tower, 5 - second spray tower, 6 - third spray tower, 7 - hydraulic cylinder, 8 - hollow outer shaft, 9 - inner rotating shaft, 10 - motor, 11 - discharge electrode, 12 - dust collecting electrode, 13 - insulating positioning plate, 14 - contact electrode, 15 - insulating sealing plate, 16 - turntable, 17 - collection bucket, 18 - hexagonal groove, 19 - spring, 20 - hexagonal shaft, 21 - cylindrical section, 22 - positioning ring, 23 - screw, 24 - nut, 25 - hexagonal head, 26 - discharge port. Specific embodiments

[0035] The following is a description of the present invention in conjunction with embodiments, but it does not constitute any limitation to the present invention. Any limited modifications made by anyone within the scope of the claims of the present invention are still within the scope of the claims of the present invention.

[0036] Embodiment 1

[0037] A combined treatment method for rare earth dust flue gas of the present invention is as follows: The discharged dust and smoke mixed gas is cooled to reach a preset initial temperature, and then passed through an electrostatic adsorption device at a set initial gas flow rate for dust removal treatment to obtain flue gas. The temperature of the dust and smoke mixed gas generated by electrolyzing rare earth powder is relatively high, up to 800 - 1100 °C. Although part of the heat can be dissipated through the transportation of a long pipeline, the temperature of the dust and smoke mixed gas transported to the dust removal tower is still relatively high. The high-temperature dust and smoke mixed gas is not conducive to electrostatic adsorption. Therefore, it is necessary to cool it first so that its temperature is about 200 °C and then send it into the dust removal tower for electrostatic adsorption. Although lower temperature is more conducive to the adsorption of rare earth dust, too low temperature of the dust and smoke mixed gas means a more efficient cooling device is required, bringing higher costs. Therefore, in this embodiment, the initial temperature is taken as 200 °C, which is a better adsorption high temperature for rare earth dust. And the effect of electrostatic adsorption is related to the gas flow rate. Therefore, in this embodiment, an initial gas flow rate is set, and 10 m / s can be adopted. After the dust and smoke mixed gas passes through the electrostatic adsorption device, the rare earth dust will be adsorbed on the dust collecting electrode of the electrostatic adsorption device, and the discharged will be flue gas. However, as the dust collected on the dust collecting electrode of the electrostatic adsorption device increases, its adsorption effect will decrease. Therefore, in this embodiment, the method of detecting the dust content in the flue gas is adopted, and whether the temperature and gas flow rate of the dust and smoke mixed gas need to be adjusted is judged according to the dust content. Specifically, when the dust content is greater than or equal to the set target threshold, the temperature and gas flow rate of the dust and smoke mixed gas are dynamically adjusted according to the dust content. The adjustment method is as follows.

[0038] The first step: When the dust content is greater than or equal to the target threshold, the initial gas flow rate of the dust and smoke mixed gas is reduced by a set speed step, such as reducing 1 m / s, to obtain a new gas flow rate, and the new temperature is calculated.

[0039] Among them, the calculation formula for the new temperature is as follows:

[0040] Tn = T0 * Vn / V0.

[0041] In the formula, Tn is the new temperature; T0 is the initial temperature, which is 200 °C; Vn is the new gas flow velocity, where n is from 1 to N; V0 is the initial gas flow temperature.

[0042] Step 2: The dust and smoke mixed gas passes through the electrostatic adsorption device at the new gas flow velocity and new temperature.

[0043] Step 3: Collect the dust content corresponding to the dust and smoke mixed gas at the new gas flow velocity and new temperature to obtain the new dust content; if the new dust content is less than the target threshold, the dust and smoke mixed gas is transported at the current temperature and velocity; if the new dust content is greater than or equal to the target threshold, perform Step 1, and at the same time, perform a loop value count; if the loop value count is equal to N, perform Step 4.

[0044] Step 4: Replace the dust collecting electrode of the electrostatic adsorption device with a new dust collecting electrode, and at the same time set the current temperature and gas flow velocity of the dust and smoke mixed gas to the initial temperature and initial gas flow velocity respectively.

[0045] When the adsorption effect does not meet the requirements, the adsorption effect is improved by reducing the gas flow velocity and temperature. And to improve the adsorption effect, the temperature of the dust and smoke mixed gas is also reduced. Generally speaking, the exhaust velocity cannot be lower than 5 m / s, otherwise rare earth dust is likely to accumulate in the pipeline. Therefore, in this embodiment, N is taken as 5. That is, when the gas flow velocity is 5 m / s and the dust and smoke mixed gas at the current temperature still does not meet the adsorption requirements by the electrostatic adsorption device, it means that there is more dust on the surface of the dust collecting electrode, resulting in the adsorption effect not meeting the requirements. At this time, the dust collecting electrode needs to be replaced and a new dust collecting electrode is used for adsorption.

[0046] When the gas flow velocity of the dust and smoke mixed gas is adjusted, obtain the real-time flow rate of the flue gas and the initial flow rate of the flue gas when the dust and smoke mixed gas is at the initial gas flow velocity, and correct the spray flow rate in the spray tower according to the real-time flow rate and the initial flow rate. Since the reduction of the gas flow velocity of the dust and smoke mixed gas leads to the reduction of the gas outlet volume of the flue gas, in order to make the spray flow rate match the gas outlet volume of the flue gas and thus achieve the purpose of saving energy consumption, it is necessary to correct the spray flow rate.

[0047] The method for correcting the spray flow rate is: use the comparison value between the real-time flow rate and the initial flow rate as the correction coefficient, calibrate the initial flow rate of the spray head according to the initial flow rate, and calculate the spray flow rate by multiplying the initial flow rate by the correction coefficient.

[0048] Embodiment 2

[0049] Refer to Figures 1-4, A combined treatment tower for rare earth dust flue gas, comprising a dust removal tower 3, a first spray tower 4, a second spray tower 5, a third spray tower 6 and an industrial control computer connected in sequence. Among them, an electrostatic adsorption device is installed in the dust removal tower 3. The air inlet of the dust removal tower 3 is connected to a gas pre-storage tower 2 for temporarily storing the dust and smoke mixed gas, so that the dust and smoke mixed gas generated by the electrolytic cell can be sucked out without stopping the machine when replacing the dust collecting electrode 12. A temperature sensor is installed in the gas pre-storage tower 2 to collect the temperature of the dust and smoke mixed gas, and this temperature will be fed back to the cooling device 1 through the industrial control computer, so as to realize the adjustment of the temperature of the dust and smoke mixed gas. A heat preservation layer is provided in the gas pre-storage tower 2 to reduce heat loss. At the same time, it adopts an upper air inlet and lower air outlet structure, which can prevent rare earth dust from accumulating inside. A cooling device 1 is installed on the pipeline between the gas pre-storage tower 2 and the dust suction port. Specifically, the cooling device 1 is mainly a heat exchanger arranged on the periphery of the exhaust pipeline. The heat of the dust and smoke mixed gas is transferred to the water in the heat exchanger through the exhaust pipeline for heat exchange, and the temperature of the dust and smoke mixed gas is adjusted by controlling the water flow. A dust detector and a gas flow detector are installed at the air outlet of the dust removal tower 3, which are used to collect the dust content and the gas flow of the flue gas respectively. The industrial control computer is used to receive the electrical signals of the temperature sensor, the dust detector and the gas flow detector, and control the electrostatic adsorption device and the spray heads in the spray tower to work according to the electrical signals by applying the above combined treatment method, so as to realize the dust removal of the dust and smoke mixed gas and the spray treatment of the flue gas.

[0050] To enable the replacement of the dust collecting electrode 12, the following improvements are made to the electrostatic adsorption device in this embodiment. In this embodiment, the electrostatic adsorption device includes a discharge electrode 11 and a dust collecting electrode 12. The discharge electrode 11 is fixedly installed in the tower body of the dust removal tower 3 between two joints. An insulating layer is provided between the discharge electrode 11 and the dust removal tower 3 to prevent the outer wall of the dust removal tower 3 from being charged. The discharge electrode 11 is a hollow structure, and the dust collecting electrode 12 is located inside the discharge electrode 11. The dust collecting electrode 12 is also a hollow structure, but an insulating closing plate 15 is fixed at its bottom, so the dust collecting electrode 12 adsorbs dust only by its side wall. A contact electrode 14 in contact with the dust collecting electrode 12 is installed on the inner side of the top of the dust removal tower 3. The contact electrode 14 is composed of an insulating block and a conductive ring located at the bottom of the insulating block. Since the upper end of the dust collecting electrode 12 is open, this design can seal the upper end opening of the dust collecting electrode 12 to prevent dust from entering the inside of the dust collecting electrode 12. Through the contact between the contact electrode 14 and the dust collecting electrode 12, its electrical connection in the electrostatic adsorption structure is realized. The connection of the contact electrode 14 and the discharge electrode 11 to the power supply circuit in the electrostatic adsorption device can refer to the connection of the existing electrostatic adsorption device. In this article, the power supply circuit and these connection methods in the electrostatic adsorption device are not improved, so no more discussion is made.

[0051] Above the dust removal tower 3, a driving assembly is installed. The driving end of the driving assembly penetrates through the dust removal tower 3 and is detachably connected to the dust collecting electrode 12, facilitating the replacement of the dust collecting electrode 12. Below the dust removal tower 3, a turntable 16 is installed, and a plurality of collecting buckets 17 are provided on the turntable 16. Among them, a hexagonal positioning groove is opened at the bottom of the collecting bucket 17, and a hexagonal head 25 matching the hexagonal positioning groove is provided below the insulating closing plate 15. After the hexagonal head 25 is inserted into the hexagonal positioning groove, the dust collecting electrode 12 can be positioned to prevent it from rotating relative to the collecting bucket 17. The collecting bucket 17 can also be positioned on the turntable 16 through a positioning groove structure or an electromagnetic adsorption structure. A discharge port 26 is provided at the bottom of the dust removal tower 3, and a valve is installed in the discharge port 26. The valve adopts a slide gate valve, and the discharge port 26 corresponds to the position of the collecting bucket 17 below it. When the dust collecting electrode 12 needs to be replaced, the driving assembly drives the dust collecting electrode 12 to enter the lower collecting bucket 17 from the discharge port 26 and then releases it. The driving assembly resets, and the turntable 16 rotates, so that the collecting bucket 17 with a new dust collecting electrode 12 moves below the discharge port 26. At this time, the driving assembly acts again to pick up the new dust collecting electrode 12 from the collecting bucket 17.

[0052] To realize the lifting drive, release and locking of the driving assembly for the dust collecting electrode 12, the driving assembly of this embodiment includes a hydraulic cylinder 7, a hollow outer shaft 8, an inner rotating shaft 9 and a motor 10. The hydraulic cylinder 7 is installed above the dust removal tower 3, and the hollow outer shaft 8 is fixedly installed on one side of the piston rod of the hydraulic cylinder 7. The hollow outer shaft 8 penetrates through the top of the dust removal tower 3 and extends into the dust collecting electrode 12. The motor 10 is fixedly installed on the top of the hollow outer shaft 8, the inner rotating shaft 9 is fixed to the output end of the motor 10, the inner rotating shaft 9 extends along the hollow outer shaft 8 to the other end thereof, and a screw rod 23 is provided at one end of the inner rotating shaft 9 extending to the end of the hollow outer shaft 8. The screw rod 23 is connected to the inner rotating shaft 9 through an elastic positioning structure, and a nut 24 is fixed on the insulating closing plate 15. The screw rod 23 is screwed into the nut 24.

[0053] Through the design of the hydraulic cylinder 7, the lifting of the hollow outer shaft 8 and the dust collecting electrode 12 is realized; and through the driving action of the motor 10 on the inner rotating shaft 9 and the screw rod 23, the connection or separation of the screw rod 23 and the nut 24 is realized, thereby realizing the connection or separation of the driving assembly and the dust collecting electrode 12. When the screw rod 23 is screwed into the nut 24, it can be lifted; when the screw rod 23 is separated from the nut 24, the dust collecting electrode 12 is released from the driving assembly. Through the design of the elastic positioning structure, the screwing in and out operation between the screw rod 23 and the nut 24 can be better realized.

[0054] Among them, regarding the elastic positioning structure, it includes a spring 19 and a hexagonal shaft 20. A hexagonal groove 18 is opened at the end of the inner rotating shaft 9. The spring 19 is placed in the hexagonal groove 18. The hexagonal shaft 20 is movably inserted into the hexagonal groove 18 and contacts the spring 19. The screw rod 23 is fixedly installed at the end of the hexagonal shaft 20. A threaded hole is opened at the notch of the hexagonal groove 18, and a positioning ring 22 is screwed into the threaded hole. The inner diameter of the inner circle of the positioning ring 22 is smaller than the outer diameter of the hexagonal shaft 20. A cylindrical section 21 is provided at the connection between the hexagonal shaft 20 and the screw rod 23, and the cylindrical section 21 is movably inserted into the positioning ring 22. The function of the hexagonal shaft 20 is to ensure that the screw rod 23 rotates with the inner rotating shaft 9; and through the mutual cooperation of the spring 19 and the cylindrical section 21, the elastic installation of the screw rod 23 is realized; the positioning ring 22 mainly plays a positioning role for the hexagonal shaft 20, so that it cannot fall off from the hexagonal groove 18, so as to smoothly lift the dust collecting electrode 12.

[0055] When the hexagonal head 25 of the dust collecting electrode 12 is located in the hexagonal positioning groove, the motor 10 drives the inner rotating shaft 9 to rotate. Due to the positioning of the hexagonal groove 18 on the hexagonal shaft 20 below the inner rotating shaft 9, the screw rod 23 rotates with the inner rotating shaft 9, so that it is screwed into or out of the nut 24. During the process of the hydraulic cylinder 7 driving the hollow outer shaft 8 to descend, when the end of the hollow outer shaft 8 approaches the insulating closing plate 15 and contacts its surface, the nut 24 will abut against the screw rod 23, causing the spring 19 to contract. At this time, due to the pressure generated by the spring 19 on the screw rod 23, the screw rod 23 can be better screwed into the nut 24. To improve the stability of lifting the dust collecting electrode 12, an insulating positioning plate 13 can also be fixedly installed in the dust collecting electrode 12, with an insertion hole opened in the middle for passing through the hollow outer shaft 8, and the edge of the insertion hole is set as a chamfer structure to facilitate the hollow outer shaft 8 to pass through the insulating positioning plate 13.

[0056] The working principle of the present invention is as follows: When the electrolytic cell works, the exhaust equipment inhales the dust and smoke mixed gas discharged from the electrolytic cell, and then sends the dust and smoke mixed gas into the cooling device 1 for cooling treatment. And when the temperature of the dust and smoke mixed gas reaches the initial temperature, the dust and smoke mixed gas is sent into the gas pre-storage tower 2. The air supply equipment in the pipeline between the gas pre-storage tower 2 and the dust removal tower 3 sends the dust and smoke mixed gas into the dust removal tower 3 at a set initial air flow rate, and the rare earth dust in the dust and smoke mixed gas is adsorbed and removed by the electrostatic adsorption device in the dust removal tower 3. The flue gas obtained after dust removal will be sent into three spray towers in sequence for spray treatment.

[0057] During the dust removal process of the electrostatic adsorption device, if the dust collection effect of the dust and smoke mixed gas still does not meet the adsorption requirements after adjusting the temperature and air flow velocity N times, it indicates that there is a lot of dust on the surface of the dust collecting electrode, resulting in the adsorption effect not meeting the requirements. At this time, the dust collecting electrode 12 needs to be replaced. When replacing, close the valve in the pipeline between the gas pre-storage tower 2 and the dust removal tower 3, then open the valve at the discharge port. At the same time, start the hydraulic cylinder 7, and drive the hollow outer shaft 8 and the dust collecting electrode 12 to move downward into the collection bucket 17 through the hydraulic cylinder 7. When the hexagon head 25 below the dust collecting electrode 12 enters the hexagon positioning groove in the collection bucket 17, start the motor 10, drive the inner rotating shaft 9 and the screw 23 to rotate through the motor 10, so that the screw 23 is disengaged from the nut 24 and the dust collecting electrode 12 is not locked. At this time, the hydraulic cylinder 7 resets, and the turntable 16 rotates to move the new dust collecting electrode 12 to below the discharge port 26. Then the hydraulic cylinder 7 is started again to extend the hollow outer shaft 8 into the new dust collecting electrode 12, and then the motor 10 is reversed to screw the screw 23 into the nut 24. Finally, the hydraulic cylinder 7 drives the hollow outer shaft 8 and the new dust collecting electrode 12 to rise and reset, the valve at the discharge port 26 is closed, and the valve in the pipeline between the gas pre-storage tower 2 and the dust removal tower 3 is opened, and it can be used normally.

[0058] The above are only the preferred embodiments of the present invention. It should be pointed out that for those skilled in the art, without departing from the structure of the present invention, several deformations and improvements can be made, which will not affect the implementation effect of the present invention and the practicability of the patent.

Claims

1. A combined treatment method for rare earth dust and flue gas, characterized in that: The method comprises: cooling the discharged dust-smoke mixed gas to a preset initial temperature, and then removing dust from the mixed gas through an electrostatic adsorption device at a set initial airflow velocity to obtain flue gas; detecting the dust content in the flue gas, and if the dust content is greater than or equal to a set target threshold, dynamically adjusting the temperature and airflow velocity of the dust-smoke mixed gas according to the dust content; When the airflow velocity of the dust-smoke mixed gas is adjusted, the real-time flow rate of the flue gas and the initial flow rate of the flue gas when the dust-smoke mixed gas is at the initial airflow velocity are obtained, and the spray flow in the spray tower is corrected according to the real-time flow rate and the initial flow rate.

2. The combined treatment method for rare earth dust and flue gas according to claim 1, characterized in that: The method for dynamically adjusting the temperature and airflow velocity of the dust-smoke mixed gas according to the initial dust content is: The first step is to reduce the initial airflow velocity of the dust-smoke mixed gas by a set velocity step length when the dust content is greater than or equal to the target threshold, obtain a new airflow velocity, and calculate a new temperature; Step 2: the dust-smoke mixed gas passes through the electrostatic adsorption device at the new air flow velocity and the new temperature; Step 3: Collect the dust content of the dust-smoke mixed gas at the new air flow speed and the new temperature to obtain a new dust content; if the new dust content is less than the target threshold, the dust-smoke mixed gas is transported at the current temperature and speed; if the new dust content is greater than or equal to the target threshold, proceed to step 1 and count the cycle value at the same time; if the cycle value count is equal to N, proceed to step 4; The fourth step is to replace the dust collecting pole of the electrostatic adsorption device with a new one, and at the same time set the current temperature and airflow velocity of the dust-smoke mixed gas to the initial temperature and initial airflow velocity respectively.

3. The combined treatment method for rare earth dust and flue gas according to claim 2, characterized in that: The new temperature calculation formula is: Tn=T0*Vn / V0; Where Tn is the new temperature; T0 is the initial temperature; Vn is the new airflow velocity, n is 1-N; V0 is the initial airflow temperature.

4. The combined treatment method for rare earth dust and flue gas according to claim 3 is characterized in that: The initial temperature is 150-200°C.

5. The combined treatment method for rare earth dust and flue gas according to claim 1, characterized in that: The correction method for the spray flow is: The comparison value between the real-time flow rate and the initial flow rate is used as a correction coefficient, the initial flow rate of the sprinkler head is calibrated according to the initial flow rate, and the sprinkler flow rate is calculated as the product of the initial flow rate and the correction coefficient.

6. A combined treatment tower for rare earth dust and flue gas, comprising a dust removal tower (3), a first spray tower (4), a second spray tower (5), a third spray tower (6) and an industrial computer connected in sequence, characterized in that: The dust removal tower (3) is equipped with an electrostatic adsorption device, the air inlet of the dust removal tower (3) is connected to the gas pre-storage tower (2), the gas pre-storage tower (2) is equipped with a temperature sensor, the pipeline between the gas pre-storage tower (2) and the dust suction port is equipped with a cooling device (1), and the air outlet of the dust removal tower (3) is equipped with a dust detector and a gas flow detector; The industrial computer is used to receive electrical signals from the temperature sensor, dust detector and gas flow detector, and control the electrostatic adsorption device and the spray head in the spray tower to work according to the combined processing method described in any one of claims 1 to 5 based on the electrical signals, so as to achieve dust removal of the dust and smoke mixed gas and spray treatment of the flue gas.

7. A combined treatment tower for rare earth dust and flue gas according to claim 6, characterized in that: The electrostatic adsorption device comprises a discharge electrode (11) and a dust collecting electrode (12); the discharge electrode (11) is fixedly installed in a dust removal tower (3), the discharge electrode (11) is a hollow structure, the dust collecting electrode (12) is located in the discharge electrode (11), and a contact electrode (14) in contact with the dust collecting electrode (12) is installed on the inner side of the top of the dust removal tower (3); a drive assembly is installed above the dust removal tower (3), the drive end of the drive assembly passes through the dust removal tower (3) and is detachably connected to the dust collecting electrode (12); a turntable (16) is installed below the dust removal tower (3), a plurality of collection barrels (17) are arranged on the turntable (16), a discharge port (26) is provided at the bottom of the dust removal tower (3), a valve is installed in the discharge port (26), and the discharge port (26) corresponds to the position of the collection barrel (17) located below it.

8. A combined treatment tower for rare earth dust and flue gas according to claim 7, characterized in that: The driving assembly comprises a hydraulic cylinder (7), a hollow outer shaft (8), an inner rotating shaft (9) and a motor (10); the hydraulic cylinder (7) is installed above the dust removal tower (3), and the hollow outer shaft (8) is fixedly installed on one side of the piston rod of the hydraulic cylinder (7); the dust collecting electrode (12) is a hollow structure, and an insulating sealing plate (15) is fixed to the bottom port of the dust collecting electrode (12); a hexagonal positioning groove is provided at the bottom of the collecting barrel (17), and a hexagonal head (25) matching the hexagonal positioning groove is provided below the insulating sealing plate (15); the hollow outer shaft (8) The motor (10) is fixedly mounted on the top of the hollow outer shaft (8), and the inner shaft (9) is fixed on the output end of the motor (10). The inner shaft (9) extends along the hollow outer shaft (8) to the other end thereof. A screw (23) is provided at one end of the inner shaft (9) extending to the end of the hollow outer shaft (8). The screw (23) is connected to the inner shaft (9) through an elastic positioning structure. A nut (24) is fixed on the insulating sealing plate (15), and the screw (23) is screwed into the nut (24).

9. A combined treatment tower for rare earth dust and flue gas according to claim 8, characterized in that: The elastic positioning structure comprises a spring (19) and a hexagonal shaft (20); a hexagonal groove (18) is provided at the end of the inner rotating shaft (9), the spring (19) is placed in the hexagonal groove (18), the hexagonal shaft (20) is movably inserted in the hexagonal groove (18) and contacts the spring (19), and the screw rod (23) is fixedly mounted on the end of the hexagonal shaft (20).

10. A combined treatment tower for rare earth dust and flue gas according to claim 9, characterized in that: A threaded hole is provided at the notch of the hexagonal groove (18), a positioning ring (22) is screwed into the threaded hole, the inner diameter of the positioning ring (22) is smaller than the outer diameter of the hexagonal shaft (20), a cylindrical section (21) is provided at the connection between the hexagonal shaft (20) and the screw rod (23), and the cylindrical section (21) is movably inserted into the positioning ring (22).

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