Equipment for recovering hydrofluoric acid from rare earth concentrate roasting tail gas

By designing multi-stage spraying, washing and absorption equipment, the problems of difficult treatment of rare earth concentrate roasted tail gas and low recovery efficiency of fluorine resources are solved, efficient purification of exhaust gas and recycling of fluorine resources are achieved, and the management cost is reduced.

CN222204808UActive Publication Date: 2024-12-20BAOTOU HUAMEI RE PRODS +1
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Patent Information

Application Number
CN202323490745.4
Authority / Receiving Office
CN · China
Patent Type
Utility models(China)
Current Assignee / Owner
Filing Date
2023-12-20
Publication Date
2024-12-20
Estimated Expiration
2033-12-20

AI Technical Summary

Technical Problem

The acidic exhaust gas generated during the roasting process of rare earth concentrate is difficult to control, costly, and the concentration of hydrofluoric acid is low, making it difficult for the existing technology to effectively recover fluorine resources.

Method used

An equipment was designed, including a first-stage power wave high-efficiency scrubber, a cyclone plate scrubber and a packing tower. Through multi-stage spray, washing and absorption processes, the spray pump, cyclone plate and filler layer can be used to achieve multiple exhaust gases. Reduce acid gas concentration and recover fluorine resources.

Benefits of technology

It realizes efficient purification of exhaust gas, reduces management costs, simplifies purification process, improves product quality, and can recover fluorine resources in one step.

✦ Generated by Eureka AI based on patent content.

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Abstract

The utility model discloses equipment for recovering hydrofluoric acid from rare earth concentrate roasting tail gas, which comprises a primary dynamic wave high-efficiency washer, an induced draft fan and an air outlet pipe, the primary dynamic wave high-efficiency washer comprises a high-temperature transition section and a reverse spraying pipe, an outlet of the high-temperature transition section is connected to the lower part of the reverse spraying pipe, and the top of the high-temperature transition section is connected with an air inlet pipe; an overflow weir is arranged in the shell; the front end of the air inlet pipe is connected with an air supplementing pipe which is provided with an automatic cold air supplementing valve; a washer nozzle is arranged at the upper part of an inner cavity of the reverse spraying pipe, the bottom of the reverse spraying pipe is connected with a first acid tank, a spraying pipe is respectively connected with the washer nozzle, the overflow weir and the first acid tank, and the spraying pipe is provided with a spraying pump; the end of the air outlet pipe is connected to the top of the reverse spraying pipe, and the induced draft fan is arranged on the air outlet pipe. The device can be used for recovering fluorine resources and realizing the recovery of acid gas.
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Description

Technical Field

[0001] The utility model belongs to the technical field of rare earth concentrate roasting tail gas treatment, and in particular relates to equipment for recovering hydrofluoric acid from rare earth concentrate roasting tail gas. Background Art

[0002] At present, rare earth concentrate is decomposed by roasting with concentrated sulfuric acid. The process has high decomposition temperature and high consumption of concentrated sulfuric acid. A large amount of mixed acidic gas containing fluorine, silicon and sulfur is produced in the roasting and decomposition process. In addition, a large amount of acidic tail gas needs to be sprayed and absorbed by a variety of combined processes. The tail gas treatment is difficult and costly, and the concentration of recovered hydrofluoric acid is low. Utility Model Content

[0003] The utility model aims to provide a device for recovering hydrofluoric acid from tail gas of rare earth concentrate roasting, which can recover fluorine resources and realize the recovery of acidic gas.

[0004] The technical solution is as follows:

[0005] Equipment for recovering hydrofluoric acid from tail gas from roasting of rare earth concentrate, comprising: a first-stage dynamic wave high-efficiency scrubber, an induced draft fan, and an air outlet pipe, wherein the first-stage dynamic wave high-efficiency scrubber comprises: a high-temperature transition section and a reverse spray pipe, wherein the outlet of the high-temperature transition section is connected to the lower part of the reverse spray pipe, the top of the high-temperature transition section is connected to an air intake pipe, and an overflow weir is arranged inside; the front end of the air intake pipe is connected to an air supply pipe, and the air supply pipe is provided with an automatic cold air supply valve; a scrubber nozzle is arranged at the upper part of the inner cavity of the reverse spray pipe, the bottom of the reverse spray pipe is connected to a first acid tank, a spray pipe is respectively connected to the scrubber nozzle, the overflow weir, and the first acid tank, and a spray pump is arranged on the spray pipe; the end of the air outlet pipe is connected to the top of the reverse spray pipe, and the induced draft fan is arranged on the air outlet pipe.

[0006] Furthermore, the first acid tank is connected to a water supply pipe, the spray pipe is connected to a heat exchanger, and the heat exchanger is provided with a water supply pipeline and a water return pipeline.

[0007] Furthermore, it also includes: a secondary cyclone plate washing tower, a cyclone plate scrubber and a washing tower nozzle are arranged inside the secondary cyclone plate washing tower, the washing tower nozzle is located at the upper part of the cyclone plate scrubber, and a second acid tank is arranged at the lower part of the secondary cyclone plate washing tower; the air outlet pipe coming out of the reverse spray pipe is connected to the lower part of the secondary cyclone plate washing tower, the upper part of the secondary cyclone plate washing tower is connected to the air outlet pipe, and the induced draft fan is arranged on the air outlet pipe leading out of the secondary cyclone plate washing tower; a spray pipe is connected between the washing tower nozzle and the second acid tank, and the spray pipe is connected to a spray pump.

[0008] Furthermore, the second acid tank is connected to a water supply pipe, the spray pipe is connected to a heat exchanger, and the heat exchanger is provided with a water supply pipeline and a water return pipeline.

[0009] Furthermore, it also includes: a three-stage packed tower, a packing layer and a packing tower nozzle are arranged inside the three-stage packed tower, the packing tower nozzle is located at the upper part of the packing layer, and a third acid tank is arranged at the lower part of the three-stage packed tower; the air outlet pipe coming out of the secondary cyclone plate washing tower is connected to the lower part of the three-stage packed tower, the upper part of the three-stage packed tower is connected to the air outlet pipe, and the induced draft fan is arranged on the air outlet pipe leading out of the three-stage packed tower; a spray pipe is connected between the packing tower nozzle and the third acid tank, and the spray pipe is connected to a spray pump.

[0010] Furthermore, the third acid tank of the three-stage packed tower is connected with a water supply pipe, the spray pipe is connected with a heat exchanger, and the heat exchanger is provided with a water supply pipeline and a water return pipeline.

[0011] Furthermore, it also includes: a fiber acid mist demister, a fiber layer is arranged inside the fiber acid mist demister, an air outlet pipe coming out of the three-stage packing tower is connected to the lower part of the fiber acid mist demister, the upper part of the fiber acid mist demister is connected to the air outlet pipe, and an induced draft fan is arranged on the air outlet pipe leading out of the fiber acid mist demister.

[0012] Compared with the prior art, the utility model has the following advantages:

[0013] When the temperature of rare earth concentrate roasting with concentrated sulfuric acid is 200-250℃, the tail gas produced in this stage is mainly fluorine-containing gas. The main components of the tail gas are HF, SiF4, CO2, SO2, water vapor and a small amount of dust and other gases. The fluorine resources can be recovered in one step, the acid gas can be recovered, and the treatment cost can be reduced.

[0014] The utility model can simplify the tail gas purification process, improve product quality, and enable the absorption process to proceed smoothly. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a structural principle diagram of equipment for recovering hydrofluoric acid from tail gas from roasting of rare earth concentrate in the utility model. DETAILED DESCRIPTION

[0016] The following description sufficiently illustrates specific embodiments of the present invention to enable those skilled in the art to practice and reproduce the same.

[0017] like Figure 1 As shown, it is a structural principle diagram of the equipment for recovering hydrofluoric acid from the tail gas of rare earth concentrate roasting in the utility model.

[0018] The equipment for recovering hydrofluoric acid from the tail gas of roasting rare earth concentrate comprises: a first-stage power wave high-efficiency scrubber 1, an induced draft fan 2, and an air outlet pipe 3. The first-stage power wave high-efficiency scrubber 1 comprises: a high-temperature transition section 11 and a reverse spray pipe 12. The outlet of the high-temperature transition section 11 is connected to the lower part of the reverse spray pipe 12. The top of the high-temperature transition section 11 is connected to an air intake pipe 14, and an overflow weir 15 is arranged inside; the front end of the air intake pipe 14 is connected to a make-up air pipe 13, and the make-up air pipe 13 is provided with an automatic cold air supply valve; a scrubber nozzle is arranged at the upper part of the inner cavity of the reverse spray pipe 12, the bottom of the reverse spray pipe 12 is connected to a first acid tank 17, a spray pipe 16 is respectively connected to the scrubber nozzle, the overflow weir 15, and the first acid tank 17, and the spray pipe 16 is provided with a spray pump 18; the end of the air outlet pipe 3 is connected to the top of the reverse spray pipe 12, and the induced draft fan 2 is arranged on the air outlet pipe 3.

[0019] The first stage roasting tail gas is introduced into the high temperature transition section 11 under the action of the induced draft fan 2. At the same time, an automatic cold air valve is set at the front end of the intake pipe 14, and the overflow weir 15 is used to cool the tail gas temperature to ensure that it is controlled between 150 and 200 ° C, which reduces the operating conditions of the equipment; the tail gas enters the high temperature transition section 11 of the first-stage power wave high-efficiency scrubber 1. The cooling of the high temperature transition section 11 prevents the high temperature strong acid from corroding the equipment; the tail gas enters the inner cavity from the lower part of the reverse spray pipe 12, and the washing liquid enters the spray pipe 16 and is sprayed out from the scrubber nozzle; the tail gas goes upward, and the washing liquid goes downward The washing liquid washes the exhaust gas in a countercurrent manner. Due to the gas-liquid momentum balance principle, a uniform turbulent reaction area is formed, which is figuratively called the foam area. In this area, the exhaust gas is cooled, the acid gas is washed, and the dust and acid mist are removed; the exhaust gas enters the air outlet pipe 3 and is driven by the induced draft fan 2 to enter the reverse spray pipe 12; after the exhaust gas and the washing liquid come into contact in the reverse spray pipe 12, due to the effect of gravity, the droplets are separated from the exhaust gas, and the acid gas in the exhaust gas is fully washed and absorbed; the washed droplets enter the first acid tank 17 from the lower part of the washing tower, and the washing liquid is circulated under the action of the spray pump 18.

[0020] The first acid tank 17 is also connected to a water supply pipe for replenishing the consumption of washing liquid.

[0021] In order to cool the washing liquid, the spray pipe 16 is connected to a heat exchanger, and the heat exchanger is provided with a water supply pipeline and a water return pipeline, so that the temperature of the washing liquid is controlled at about 70°C.

[0022] In order to further purify the tail gas, it also includes a secondary cyclone plate washing tower 4, a tertiary packed tower 5, and a fiber acid mist demister 6, which can be arranged separately or connected in series between the primary power wave high-efficiency scrubber 1 and the induced draft fan 2.

[0023] The secondary cyclone plate washing tower 4 is provided with (four layers) cyclone plate washing device 41 and washing tower nozzle inside, and the lower part is provided with the second acid tank 42, the air outlet pipe 3 coming out of the reverse spray pipe 12 is connected to the lower part of the secondary cyclone plate washing tower 4, the upper part of the secondary cyclone plate washing tower 4 is connected to the air outlet pipe 3, and the induced draft fan 2 is arranged on the air outlet pipe 3 leading out of the secondary cyclone plate washing tower 4; a spray pipe 16 is connected between the washing tower nozzle and the second acid tank 42, and the spray pipe 16 is connected to the spray pump 18. Similarly, the second acid tank 42 of the secondary cyclone plate washing tower 4 is connected to the water replenishment pipe for replenishing the consumption of washing liquid; in order to cool the washing liquid, the spray pipe 16 is connected to the heat exchanger, and the heat exchanger is provided with a water supply pipeline and a water return pipeline.

[0024] The tail gas enters the secondary cyclone plate scrubber 4 after being defogged by the primary power wave high-efficiency scrubber 1. The tail gas flows upward from the bottom of the tower and is washed and absorbed again. The tail gas passes through the cyclone plate scrubber 41 and is discharged from the top. The guiding effect of the cyclone plate scrubber 41 causes the tail gas to rotate and rise, and the droplets flow downward on the cyclone plate scrubber 41, so that there is a large contact area between the gas and the liquid. The droplets are driven to rotate by the airflow, and the centrifugal force generated strengthens the gas-liquid contact, and finally thrown to the tower and flows down. After fully contacting with the gas, the liquid can be effectively separated, and its gas-liquid load is several times greater than that of the commonly used tower plates. The circulating liquid enters the inner wall from the external circulating water pipe of the cyclone tower, and the atomizing nozzle forms evenly distributed droplets on the cyclone to fully contact the tail gas, and fully reacts with the tail gas to form absorption and washing. At the same time, larger dust particles are removed under the action of centrifugal force, and smaller dust particles are condensed into larger dust particles or droplets by the collision and interception of the droplets, and multiple Brownian diffusions. The droplets are thrown to the tower wall and discharged into the second acid tank 42 at the bottom of the tower. After two-stage high-efficiency washing and absorption, the exhaust gas concentration, temperature and dust content are greatly reduced to ensure the exhaust gas emission requirements.

[0025] The three-stage packing tower 5 is provided with a packing layer 51 and a packing tower nozzle inside. The packing tower nozzle is located at the upper part of the packing layer, and the lower part is provided with a third acid tank 52. The outlet pipe 3 from the secondary cyclone plate washing tower 4 is connected to the lower part of the three-stage packing tower 5. The upper part of the three-stage packing tower 5 is connected to the outlet pipe 3. The induced draft fan 2 is arranged on the outlet pipe 3 led out of the three-stage packing tower 5. A spray pipe 16 is connected between the packing tower nozzle and the third acid tank 52, and the spray pipe 16 is connected to a spray pump 18. Similarly, the third acid tank 52 of the three-stage packing tower 5 is connected to a water supply pipe for replenishing the consumption of washing liquid. In order to cool the washing liquid, the spray pipe 16 is connected to a heat exchanger, and the heat exchanger is provided with a water supply pipeline and a water return pipeline.

[0026] The tail gas enters the lower part of the three-stage packed tower 5, and is led upward through the packing layer 51 and out from the outlet pipe 3 connected to the upper part. Due to the increased specific surface area of ​​the packing layer 51, the tail gas is fully diffused and washed and absorbed again by the dilute acid circulating liquid to meet the emission requirements of the system.

[0027] A fiber layer 61 is arranged inside the fiber acid mist demister 6, the air outlet pipe 3 coming out of the three-stage packing tower 5 is connected to the lower part of the fiber acid mist demister 6, the upper part of the fiber acid mist demister 6 is connected to the air outlet pipe 3, and the induced draft fan 2 is arranged on the air outlet pipe 3 leading out of the fiber acid mist demister 6.

[0028] In order to ensure effective emission requirements, a fiber acid mist demister 6 is installed after the three-stage packed tower 5 to prevent the acid mist and water vapor entrained in the tail gas from affecting the detection effect. The tail gas is discharged to the purification system through the induced draft fan 2.

[0029] The terms used in the present invention are illustrative and exemplary, rather than restrictive. Since the present invention can be implemented in various forms without departing from the spirit or essence of the technical solution, it should be understood that the above embodiments are not limited to any of the aforementioned details, but should be widely interpreted within the spirit and scope defined by the attached claims, so all changes and modifications falling within the scope of the claims or their equivalents should be covered by the attached claims.

Claims

1. A device for recovering hydrofluoric acid from the tail gas of rare earth concentrate roasting, characterized in that: include: A first-stage dynamic wave high-efficiency scrubber, an induced draft fan, and an air outlet pipe. The first-stage dynamic wave high-efficiency scrubber includes: a high-temperature transition section and a reverse spray pipe. The outlet of the high-temperature transition section is connected to the lower part of the reverse spray pipe, and the top of the high-temperature transition section is connected to an air intake pipe, and an overflow weir is arranged inside; the front end of the air intake pipe is connected to a make-up air pipe, and the make-up air pipe is provided with an automatic cold air supply valve; a scrubber nozzle is arranged on the upper part of the inner cavity of the reverse spray pipe, and the bottom of the reverse spray pipe is connected to the first acid tank, and the spray pipe is respectively connected to the scrubber nozzle, the overflow weir, and the first acid tank, and the spray pipe is provided with a spray pump; the end of the air outlet pipe is connected to the top of the reverse spray pipe, and the induced draft fan is arranged on the air outlet pipe.

2. The equipment for recovering hydrofluoric acid from the tail gas of rare earth concentrate roasting according to claim 1, characterized in that: The first acid tank is connected with a water supply pipe, the spray pipe is connected with a heat exchanger, and the heat exchanger is provided with a water supply pipeline and a water return pipeline.

3. The equipment for recovering hydrofluoric acid from the tail gas of rare earth concentrate roasting according to claim 1, characterized in that: Also includes: A secondary cyclone plate washing tower, wherein a cyclone plate scrubber and a washing tower nozzle are arranged inside the secondary cyclone plate washing tower, the washing tower nozzle is located at the upper part of the cyclone plate scrubber, and a second acid tank is arranged at the lower part of the secondary cyclone plate washing tower; the air outlet pipe coming out of the reverse spray pipe is connected to the lower part of the secondary cyclone plate washing tower, the upper part of the secondary cyclone plate washing tower is connected to the air outlet pipe, and the induced draft fan is arranged on the air outlet pipe leading out of the secondary cyclone plate washing tower; a spray pipe is connected between the washing tower nozzle and the second acid tank, and the spray pipe is connected to a spray pump.

4. The equipment for recovering hydrofluoric acid from the tail gas of rare earth concentrate roasting as claimed in claim 3, characterized in that: The second acid tank is connected with a water supply pipe, the spray pipe is connected with a heat exchanger, and the heat exchanger is provided with a water supply pipeline and a water return pipeline.

5. The equipment for recovering hydrofluoric acid from the tail gas of rare earth concentrate roasting as claimed in claim 3, characterized in that: Also includes: A three-stage packing tower is provided with a packing layer and a packing tower nozzle inside the three-stage packing tower, the packing tower nozzle is located at the upper part of the packing layer, and a third acid tank is provided at the lower part of the three-stage packing tower; the air outlet pipe coming out of the secondary cyclone plate washing tower is connected to the lower part of the three-stage packing tower, the upper part of the three-stage packing tower is connected to the air outlet pipe, and the induced draft fan is arranged on the air outlet pipe leading out of the three-stage packing tower; a spray pipe is connected between the packing tower nozzle and the third acid tank, and the spray pipe is connected to a spray pump.

6. The equipment for recovering hydrofluoric acid from the tail gas of rare earth concentrate roasting as claimed in claim 5, characterized in that: The third acid tank of the three-stage packed tower is connected with a water supply pipe, the spray pipe is connected with a heat exchanger, and the heat exchanger is provided with a water supply pipeline and a water return pipeline.

7. The equipment for recovering hydrofluoric acid from the tail gas of rare earth concentrate roasting according to claim 5, characterized in that: Also includes: A fiber acid mist demister is provided with a fiber layer inside, an air outlet pipe coming out of a three-stage packing tower is connected to the lower part of the fiber acid mist demister, the upper part of the fiber acid mist demister is connected to the air outlet pipe, and an induced draft fan is provided on the air outlet pipe leading out of the fiber acid mist demister.