CN111495120A - Rare earth concentrate acidified tail gas treatment system and method based on indirect-heating type rotary reactor - Google Patents
Rare earth concentrate acidified tail gas treatment system and method based on indirect-heating type rotary reactor Download PDFInfo
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- CN111495120A CN111495120A CN202010328166.1A CN202010328166A CN111495120A CN 111495120 A CN111495120 A CN 111495120A CN 202010328166 A CN202010328166 A CN 202010328166A CN 111495120 A CN111495120 A CN 111495120A
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- 229910052761 rare earth metal Inorganic materials 0.000 title claims abstract description 91
- 150000002910 rare earth metals Chemical class 0.000 title claims abstract description 91
- 238000010438 heat treatment Methods 0.000 title claims abstract description 61
- 238000000034 method Methods 0.000 title claims abstract description 52
- 239000012141 concentrate Substances 0.000 title claims abstract description 42
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 claims abstract description 1124
- 238000005406 washing Methods 0.000 claims abstract description 391
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 222
- KRHYYFGTRYWZRS-UHFFFAOYSA-N Fluorane Chemical compound F KRHYYFGTRYWZRS-UHFFFAOYSA-N 0.000 claims abstract description 172
- 238000005554 pickling Methods 0.000 claims abstract description 31
- 230000020477 pH reduction Effects 0.000 claims abstract description 29
- 238000010521 absorption reaction Methods 0.000 claims abstract description 27
- 239000006096 absorbing agent Substances 0.000 claims description 89
- 239000007788 liquid Substances 0.000 claims description 75
- 239000007921 spray Substances 0.000 claims description 65
- 239000002253 acid Substances 0.000 claims description 57
- 238000005507 spraying Methods 0.000 claims description 41
- RAHZWNYVWXNFOC-UHFFFAOYSA-N Sulphur dioxide Chemical compound O=S=O RAHZWNYVWXNFOC-UHFFFAOYSA-N 0.000 claims description 35
- 238000007599 discharging Methods 0.000 claims description 12
- HIFJUMGIHIZEPX-UHFFFAOYSA-N sulfuric acid;sulfur trioxide Chemical compound O=S(=O)=O.OS(O)(=O)=O HIFJUMGIHIZEPX-UHFFFAOYSA-N 0.000 claims description 11
- 239000003513 alkali Substances 0.000 claims description 9
- 238000005086 pumping Methods 0.000 claims description 7
- 238000007865 diluting Methods 0.000 claims description 2
- 239000000428 dust Substances 0.000 abstract description 10
- 238000011084 recovery Methods 0.000 abstract description 3
- 230000000903 blocking effect Effects 0.000 abstract 1
- 239000007789 gas Substances 0.000 description 246
- AKEJUJNQAAGONA-UHFFFAOYSA-N sulfur trioxide Chemical compound O=S(=O)=O AKEJUJNQAAGONA-UHFFFAOYSA-N 0.000 description 36
- 239000000203 mixture Substances 0.000 description 22
- 229910004014 SiF4 Inorganic materials 0.000 description 6
- 238000003723 Smelting Methods 0.000 description 6
- ABTOQLMXBSRXSM-UHFFFAOYSA-N silicon tetrafluoride Chemical compound F[Si](F)(F)F ABTOQLMXBSRXSM-UHFFFAOYSA-N 0.000 description 5
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 description 4
- 238000006243 chemical reaction Methods 0.000 description 4
- 239000003546 flue gas Substances 0.000 description 4
- 238000009833 condensation Methods 0.000 description 3
- 230000005494 condensation Effects 0.000 description 3
- 230000007547 defect Effects 0.000 description 3
- 239000002699 waste material Substances 0.000 description 3
- 238000004891 communication Methods 0.000 description 2
- 239000000110 cooling liquid Substances 0.000 description 2
- 238000000354 decomposition reaction Methods 0.000 description 2
- 229910052500 inorganic mineral Inorganic materials 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 239000011707 mineral Substances 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 239000002994 raw material Substances 0.000 description 2
- 238000006467 substitution reaction Methods 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 1
- IKNAJTLCCWPIQD-UHFFFAOYSA-K cerium(3+);lanthanum(3+);neodymium(3+);oxygen(2-);phosphate Chemical group [O-2].[La+3].[Ce+3].[Nd+3].[O-]P([O-])([O-])=O IKNAJTLCCWPIQD-UHFFFAOYSA-K 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000005265 energy consumption Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000001704 evaporation Methods 0.000 description 1
- 230000008020 evaporation Effects 0.000 description 1
- 238000009854 hydrometallurgy Methods 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- 229910052590 monazite Inorganic materials 0.000 description 1
- 238000012827 research and development Methods 0.000 description 1
- 239000000779 smoke Substances 0.000 description 1
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
- B01D53/14—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols by absorption
- B01D53/18—Absorbing units; Liquid distributors therefor
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
- B01D53/26—Drying gases or vapours
- B01D53/263—Drying gases or vapours by absorption
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2257/00—Components to be removed
- B01D2257/20—Halogens or halogen compounds
- B01D2257/204—Inorganic halogen compounds
- B01D2257/2047—Hydrofluoric acid
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2257/00—Components to be removed
- B01D2257/30—Sulfur compounds
- B01D2257/302—Sulfur oxides
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02C—CAPTURE, STORAGE, SEQUESTRATION OR DISPOSAL OF GREENHOUSE GASES [GHG]
- Y02C20/00—Capture or disposal of greenhouse gases
- Y02C20/30—Capture or disposal of greenhouse gases of perfluorocarbons [PFC], hydrofluorocarbons [HFC] or sulfur hexafluoride [SF6]
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- Engineering & Computer Science (AREA)
- Analytical Chemistry (AREA)
- General Chemical & Material Sciences (AREA)
- Oil, Petroleum & Natural Gas (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Treating Waste Gases (AREA)
- Heat Treatment Of Water, Waste Water Or Sewage (AREA)
Abstract
The invention discloses a rare earth concentrate acidification tail gas treatment system and method based on an indirect-heating type rotary reactor, which comprises at least two stages of pickling devices, two stages of gas absorption devices, two stages of washing devices and two demisting devices; the first-stage pickling device in the pickling device is communicated with the acidified tail gas pipeline, all stages are communicated in sequence, and the final-stage pickling device is communicated with the gas absorption device and the second-stage pickling device respectively; the gas absorption device is respectively communicated with the hydrofluoric acid pipeline and the water washing device; the second-stage pickling device is communicated with the roasting tail gas pipeline, and the final-stage pickling device is communicated with the demisting device; the washing devices at all levels are sequentially communicated, the final-stage washing device is respectively communicated with the demisting device and the water pipeline, and the first-stage washing circulating pump is communicated with the first-stage gas absorption device. The concentration of hydrofluoric acid and the concentration of sulfuric acid obtained by the system recovery are higher, so that dust carried in tail gas is prevented from easily blocking a heat exchanger, the resource utilization rate of rare earth is improved, and the equipment investment is reduced.
Description
Technical Field
The invention relates to the technical field of rare earth hydrometallurgy environment protection, in particular to a tail gas treatment system and a tail gas treatment method suitable for an indirect-heating type rotary reactor to carry out rare earth concentrate acidification roasting.
Background
The rare earth has wide application in civil and military, is indispensable raw material for advanced equipment manufacturing industry, new energy, emerging industry and other high and new technology industries, and is precious and key strategic resource. At present, the smelting of rare earth concentrate in China mainly adopts a concentrated sulfuric acid high-temperature intensified roasting method, and the method comprises the steps of putting 50% of rare earth concentrate and sulfuric acid with the concentration of more than 92% into an internal heating type rotary kiln according to the mass ratio of 1: 1.3-1.4, introducing high-temperature hot flue gas, roasting at the temperature of 600-800 ℃ and roasting for 1.5-3 hours.
Because the method adopts internal heating type heating, the rare earth concentrate and sulfuric acid are subjected to chemical reaction in the rotary kiln to generate gas and a large amount of hot flue gas for heating, and the gas is mixed to be used as tail gas, so that the defect of large tail gas treatment amount exists. The process is gradually replaced by an indirect-heating type rotary reactor rare earth concentrate acidizing roasting process. The rare earth concentrate acidizing roasting process of the indirect-heating type rotary reactor adopts the indirect-heating type rotary reactor to heat materials, hot flue gas indirectly heats the materials, and acid gas generated by reaction is used as tail gas and is not mixed with the hot flue gas, so that the tail gas treatment capacity is greatly reduced.
The rare earth concentrate acidizing and roasting process of the indirect-heating type rotary reactor respectively adopts the indirect-heating type rare earth acidizing rotary reactor and the indirect-heating type rare earth roasting rotary reactor to acidize and roast the rare earth concentrate.
In an indirect rare earth acidification rotary reactor, mainly the reaction between minerals and sulfuric acid is carried out: comprises the decomposition of bastnaesite, the decomposition of monazite, the reaction of impurity minerals and concentrated sulfuric acid, and the tail gas discharged from the acidification rotary reactor mainly contains H2O、HF、H2SO4(g)、CO2、SO3、SiF4And a small amount of dust.
In the indirect-heating rare-earth roasting rotary reactor, the excess sulfuric acid is pyrolyzed and discharged from the roasting rotary reactorThe tail gas mainly contains H2O、H2SO4(g)、SO3、SO2、O2And a small amount of dust.
Compared with the prior art, the tail gas discharged by the rare earth concentrate acidizing roasting process of the indirect-heating rotary reactor has the characteristics of less total amount of the tail gas and high concentration of acid gas components because the tail gas does not contain smoke. Aiming at the tail gas characteristics of the novel process for acidifying and roasting the rare earth concentrate in the indirect-heating rotary reactor, the research and development of a tail gas treatment system and a method suitable for the tail gas treatment system are necessary.
Patent rare earth concentrate multistage roasting tail gas respectively recovery method and device (CN 102489034A), disclose: step one, tail gas collection: introducing tail gas generated by the first-stage roasting into a first tubular heat exchanger 1, mixing tail gas generated by the second stage and the later stage, and introducing the mixed tail gas into a second tubular heat exchanger 2; step two, condensation and absorption: self-condensing the tail gas produced by the first-stage roasting in a first tubular heat exchanger, self-condensing the tail gas mixture produced by the second stage and the later stages in a second tubular heat exchanger 2, generating cooling liquid rich in hydrofluoric acid in the first tubular heat exchanger 1, and generating cooling liquid rich in sulfuric acid in the second tubular heat exchanger 2. Wherein, the hydrofluoric acid is rich, which means that the content of the hydrofluoric acid reaches 20.29%; the sulfuric acid content is 80%. And thirdly, introducing the gas mixture which cannot be condensed into a tunnel type tail gas absorber, spraying cold water or alkali liquor, and performing secondary absorption on the residual acid in the combined tail gas. Fourthly, the exhaust gas reaches the standard.
The above method has the following disadvantages:
1. the concentration of the recovered acid is low. Although the hydrofluoric acid and the sulfuric acid are respectively recovered by the method, the tail gas contains a large amount of water vapor, and the water vapor is simultaneously condensed when the tail gas is self-condensed in a heat exchanger, so that the content of the recovered hydrofluoric acid can only reach 20.29 percent, and the content of the recovered sulfuric acid can only reach 80 percent. If the concentration of the acid is to be increased, additional evaporation and concentration equipment and energy consumption are required.
2. The tube type heat exchanger is adopted to condense the tail gas, and when the tail gas enters the heat exchanger for condensation, dust carried in the tail gas is easy to adhere to the wall, so that the heat exchange effect is reduced, the heat exchanger is blocked, and the continuous and stable operation of the system is influenced; and dust in the tail gas belongs to precious rare earth raw materials, and is finally discharged out of the system, so that not only is rare earth resource waste caused, but also the dust becomes dangerous waste to pollute the environment.
3. When the tail gas is self-condensed in the heat exchanger, the water vapor component and the acid gas component are simultaneously condensed, and the water vapor has larger latent heat, so that the heat exchange area of the required heat exchanger is overlarge, and the equipment investment cost is high.
Disclosure of Invention
In order to solve the defects in the prior art, the invention aims to provide a tail gas treatment system and a tail gas treatment method suitable for an indirect-heating type rotary reactor to carry out rare earth concentrate acidizing roasting, and in the process of treating the tail gas of the indirect-heating type rotary reactor to carry out rare earth concentrate acidizing roasting, hydrofluoric acid and sulfuric acid can be respectively recovered, and simultaneously, compared with the prior art, the hydrofluoric acid content and the sulfuric acid content obtained by recovery are higher, and the technical defects that dust blocks a heat exchanger and rare earth resources are wasted in the prior art are avoided, so that the resource utilization rate of rare earth is improved, the area of the heat exchanger is reduced, and the equipment investment is reduced.
The invention is realized by the following technical scheme.
A rare earth concentrate acidification tail gas treatment system based on an indirect heating type rotary reactor comprises at least two stages of pickling devices, two stages of gas absorption devices, two stages of washing devices and two demisting devices;
in the pickling device, a first-stage pickling device is communicated with an acidified tail gas pipeline, all stages of the first-stage pickling device are sequentially communicated, and a final-stage pickling device is respectively communicated with a gas absorption device and a second-stage pickling device; the gas absorption device is respectively communicated with the hydrofluoric acid pipeline and the water washing device;
the second-stage pickling device is communicated with the roasting tail gas pipeline, all stages of the second-stage pickling device are sequentially communicated, and the final-stage pickling device is communicated with the demisting device;
the washing devices at all levels are sequentially communicated, the last-stage washing device is respectively communicated with the demisting device and the water pipeline, the washing circulating pumps of the washing devices at all levels are sequentially communicated with the upper-stage water circulating pump, and the first-stage washing circulating pump is communicated with the first-stage gas absorption device.
With respect to the above technical solutions, the present invention has a further preferable solution:
preferably, each stage of pickling device comprises a sulfuric acid washing tower, a sulfuric acid circulating pool, a sulfuric acid circulating pump and a sulfuric acid cooler, wherein the sulfuric acid washing tower, the sulfuric acid circulating pool, the sulfuric acid circulating pump, the sulfuric acid cooler and the sulfuric acid washing tower are sequentially communicated in a circulating manner.
Preferably, the first stage of sulfuric acid washing tower is communicated with the sulfuric acid washing towers of the stage in sequence from the top; the final stage sulfuric acid washing tower is communicated to a gas absorption device from the top; the sulfuric acid cooler of the final stage acid washing device of the first stage acid washing device is communicated to the sulfuric acid washing tower of the final stage acid washing device of the second stage acid washing device.
Preferably, the second-stage sulfuric acid washing tower is sequentially communicated with the sulfuric acid washing towers from the top; the final stage sulfuric acid washing tower is communicated to a demister from the top.
Preferably, the gas absorption device comprises a plurality of stages of gas absorbers which are sequentially communicated, the last stage of gas absorbers are communicated with hydrofluoric acid circulating pools respectively, and the hydrofluoric acid circulating pools are communicated with a hydrofluoric acid pipeline and the first stage of gas absorbers through a hydrofluoric acid circulating pump.
Preferably, the washing device comprises a washing tower, a washing circulation tank and a washing circulation pump, and the washing tower, the washing circulation tank, the washing circulation pump and the washing tower are sequentially communicated in a circulating manner.
Preferably, the water washing tower is replaced by an alkali washing tower sprayed with alkali liquor.
Preferably, each stage of water washing tower is communicated with the secondary water washing tower from the top; the last stage water washing tower is communicated to the demister from the top.
Preferably, the demister is communicated with a tail gas purifying pipeline or a sulfur dioxide acid making device through a fan.
The invention correspondingly provides a rare earth concentrate acidification tail gas treatment method, which comprises the following steps:
and (3) acidizing tail gas treatment:
1) spraying 92-96% concentrated sulfuric acid spray liquid when acidified tail gas enters a 1# sulfuric acid washing tower of a first-stage acid washing device, discharging the tail gas to a 2# sulfuric acid washing tower, diluting the diluted sulfuric acid to fall into a 1# sulfuric acid circulating tank, introducing fuming sulfuric acid into the 1# sulfuric acid circulating tank, pumping the fuming sulfuric acid into a 1# sulfuric acid cooler, circulating one part of the fuming sulfuric acid to the 1# sulfuric acid washing tower, and removing the other part of the fuming sulfuric acid to the 2# sulfuric acid washing tower;
2) the acidified tail gas passing through the 1# sulfuric acid washing tower enters a 2# sulfuric acid washing tower, concentrated sulfuric acid and self-circulation acid of a 1# sulfuric acid cooler are used for spraying, the tail gas is discharged from the top of the tower and enters a 1-stage absorber of a gas absorption device, 89-92% diluted sulfuric acid falls into a 2# sulfuric acid circulation tank and is pumped into the 2# sulfuric acid cooler, one part of the sulfuric acid is circulated to the 2# sulfuric acid washing tower, and the other part of the sulfuric acid is sent to a 4# sulfuric acid washing tower of a second-stage acid washing device;
3) acidified tail gas and hydrofluoric acid spray liquid of a No. 2 sulfuric acid washing tower sequentially enter a No. 1 absorber and a No. 2 absorber of a gas absorption device, liquid films are formed on tube passes of the No. 1 absorber and the No. 2 absorber, the residual tail gas is discharged to the No. 1 water washing tower of the water washing device, concentrated hydrofluoric acid with the concentration of 30-34% falls into a hydrofluoric acid circulating pool, one part of the concentrated hydrofluoric acid is pumped into the No. 1 absorber, and the other part of the concentrated hydrofluoric acid is pumped to a hydrofluoric acid storage tank;
4) the acidified tail gas discharged by the 2-stage absorber sequentially passes through the three-stage water washing tower, demisted by the 1# demister and discharged from the 1# fan after reaching the standard; pumping a small amount of water back to a 3# water washing tower, a 2# water washing tower and a 1# water washing tower respectively, and pumping the other part of water back to a 2# water washing circulating pool, a 1# water washing circulating pool and a 1-stage absorber respectively;
roasting tail gas treatment:
1) after the roasting tail gas enters a 3# sulfuric acid washing tower of a second-stage acid washing device, the roasting tail gas is sprayed and discharged to the 4# sulfuric acid washing tower through self-circulating 90-94% concentrated sulfuric acid and 89-93% concentrated sulfuric acid from the 4# sulfuric acid washing tower; the sprayed concentrated sulfuric acid falls into a 3# sulfuric acid circulating pool, one part of the concentrated sulfuric acid is removed from a 3# sulfuric acid cooler to a 3# sulfuric acid washing tower, the other part of the concentrated sulfuric acid is divided into recycled sulfuric acid and discharged sulfuric acid, the recycled sulfuric acid returns to an indirect-heating rare earth acidification rotary reactor, and the discharged sulfuric acid is filtered and then discharged to a sulfuric acid storage tank;
2) the roasting tail gas of the 3# sulfuric acid washing tower of the second-stage acid washing device enters a 4# sulfuric acid washing tower, is sprayed by 88.5-92.5% concentrated sulfuric acid from a 4# sulfuric acid cooler and 88-92% concentrated sulfuric acid spray liquid from a 2# sulfuric acid circulating pump, and is demisted by a 2# demister, and is discharged from a 2# fan to an SO2 acid making device;
concentrated sulfuric acid falls into a 4# sulfuric acid circulating pool, one part of the concentrated sulfuric acid is removed from a 4# sulfuric acid cooler, the cooled sulfuric acid is circulated back to a 4# sulfuric acid washing tower, and the other part of the concentrated sulfuric acid is removed from a 3# sulfuric acid washing tower.
Due to the adoption of the technical scheme, the invention has the following beneficial effects:
1. the invention adopts concentrated sulfuric acid washing to separate water vapor and HF gas in the acidified tail gas, absorbs the water vapor in the acidified tail gas, and then recovers the HF gas, thereby improving the concentration of the recovered hydrofluoric acid, wherein the concentration of the recovered hydrofluoric acid is more than or equal to 30%.
2. The invention adopts concentrated sulfuric acid for washing, absorbs water vapor, sulfur trioxide gas and sulfuric acid vapor in roasting tail gas, has higher concentration of the recovered sulfuric acid, has the concentration of the recovered sulfuric acid more than or equal to 90 percent, and can be directly used as the feeding acid.
4. And finally, taking the washed concentrated sulfuric acid containing rare earth concentrate dust as the feeding concentrated sulfuric acid of the indirect-type rare earth acidification rotary reactor. The washed concentrated sulfuric acid containing the rare earth concentrate dust is recycled as the feeding concentrated sulfuric acid, so that the resource utilization rate of the rare earth is improved, and no waste liquid is discharged.
3. According to the method, tower equipment is adopted for tail gas treatment, so that the problem that in the prior art, when tail gas enters a heat exchanger for condensation, dust carried in the tail gas easily blocks the heat exchanger to influence continuous and stable operation of a system is solved.
5. The area of the heat exchanger can be reduced, and the equipment investment is reduced.
Drawings
The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the invention and together with the description serve to explain the principles of the invention:
FIG. 1 is a process flow diagram of the present invention.
Wherein ① acidified tail gas, ② fuming sulfuric acid, ③ hydrofluoric acid, ④ roasted tail gas, ⑤ recycled sulfuric acid, ⑥ exhausted sulfuric acid, ⑦ purified tail gas, ⑧ water and ⑨ sulfur dioxide (SO 2 acid-making device).
111 is a 1# sulfuric acid scrubber; 112 is a No. 1 sulfuric acid circulating tank; 113 is a No. 1 sulfuric acid circulating pump; 114 is a 1# sulfuric acid cooler;
121 is a No. 2 sulfuric acid washing tower; 122 is a 2# sulfuric acid circulating tank; 123 is a 2# sulfuric acid circulating pump; 124 is a 2# sulfuric acid cooler;
211 is a 3# sulfuric acid washing tower; 212 is a 3# sulfuric acid circulating tank; 213 is a 3# sulfuric acid circulating pump; 214 is a 3# sulfuric acid cooler;
221 is a No. 4 sulfuric acid washing tower; 222 is a 4# sulfuric acid circulating tank; no. 4 sulfuric acid circulating pump 223; 224 is a 4# sulfuric acid cooler;
131 is a 1-stage absorber; 132 is a 2-stage absorber; 133 is a hydrofluoric acid circulating tank; 134 is a hydrofluoric acid circulating pump;
141 is a No. 1 water washing tower; 142 is a No. 1 water washing circulating pool; 143 is a No. 1 water washing circulating pump;
151 is a No. 2 water washing tower; 152 is a No. 2 water washing circulating pool; 153 is a No. 2 water washing circulating pump;
161 is a No. 3 water washing tower; 162 is a No. 3 water washing circulating pool; 163 is a No. 3 water washing circulating pump;
171 is a No. 1 demister; 181 is a No. 1 fan; 231 is a No. 2 demister; 241 is 2# blower.
Detailed Description
The present invention will now be described in detail with reference to the drawings and specific embodiments, wherein the exemplary embodiments and descriptions of the present invention are provided to explain the present invention without limiting the invention thereto.
As shown in fig. 1, a rare earth concentrate acidification tail gas treatment system based on an indirect-heating type rotary reactor provided by an embodiment of the present invention includes a two-stage acid washing device, a two-stage gas absorption device, a three-stage water washing device, and two demisting devices.
The first-stage pickling device comprises a 1# sulfuric acid washing tower 111, a 1# sulfuric acid circulating tank 112, a 1# sulfuric acid circulating pump 113 and a 1# sulfuric acid cooler 114; a 2# sulfuric acid washing tower 121, a 2# sulfuric acid circulation tank 122, a 2# sulfuric acid circulation pump 123 and a 2# sulfuric acid cooler 124.
In the first-stage pickling device, a 1# sulfuric acid washing tower 111 is in pipeline communication with the acidified tail gas ①, the 1# sulfuric acid washing tower 111 is in pipeline communication with a 2# sulfuric acid washing tower 121, a 1# sulfuric acid circulation tank 112 and a 2# sulfuric acid circulation tank 122 are respectively communicated with the 1# sulfuric acid washing tower 111 and the 2# sulfuric acid washing tower 121, and the 1# sulfuric acid circulation tank 112 and the 2# sulfuric acid circulation tank 122 are respectively communicated with a 1# sulfuric acid cooler 114 and a 2# sulfuric acid cooler 124 to the 1# sulfuric acid washing tower 111 and the 2# sulfuric acid washing tower 121 through a 1# sulfuric acid circulation pump 113 and a 2# sulfuric acid circulation pump 123.
The 2# sulfuric acid washing tower 121 is sequentially communicated with two-stage gas absorption devices, each two-stage gas absorption device comprises a 1-stage absorber 131, a 2-stage absorber 132 and a hydrofluoric acid circulating pool 133, and the hydrofluoric acid circulating pool 133 is respectively communicated with the 1-stage absorber 131 and a hydrofluoric acid ③ pipeline through a hydrofluoric acid circulating pump 134.
The 2-stage absorber 132 is communicated with a three-stage water washing device, and the three-stage water washing device comprises a 1# water washing tower 141, a 1# water washing circulating pool 142 and a 1# water washing circulating pump 143; a # 2 water washing tower 1512# water washing circulation tank 152 and a # 2 water washing circulation pump 153; a 3# water washing tower 161, a 3# water washing circulation tank 162 and a 3# water washing circulation pump 163.
The 1# water washing tower 141 is sequentially communicated with the 2# water washing tower 151 and the 3# water washing tower 161, the 1# water washing tower 141, the 2# water washing tower 151 and the 3# water washing tower 161 are respectively communicated with the 1# water washing circulation tank 142, the 2# water washing circulation tank 152 and the 3# water washing circulation tank 162, the 1# water washing circulation tank 142, the 2# water washing circulation tank 152 and the 3# water washing circulation tank 162 are respectively communicated with the 1# water washing tower 141, the 2# water washing tower 151 and the 3# water washing tower 161 through the 1# water washing circulation pump 143, the 2# water washing circulation pump 153 and the 3# water washing circulation pump 163, the 1# water washing circulation pump 143 is communicated with the 1-stage absorber 131, the 3# water washing tower 161 is communicated with the 1# demister 171, the 1# water washing circulation pump 171 is communicated with the 1# fan 181, and the 3# water washing circulation tank 162 is communicated with the 3# water washing circulation pump 162.
The second-stage pickling device comprises a 3# sulfuric acid washing tower 211, a 3# sulfuric acid circulating tank 212, a 3# sulfuric acid circulating pump 213 and a 3# sulfuric acid cooler 214; a 4# sulfuric acid washing tower 221, a 4# sulfuric acid circulation tank 222, a 4# sulfuric acid circulation pump 223, and a 4# sulfuric acid cooler 224.
The roasting tail gas ④ is sequentially communicated with a 3# sulfuric acid washing tower 211 and a 4# sulfuric acid washing tower 221 through pipelines, the 3# sulfuric acid washing tower 211 and the 4# sulfuric acid washing tower 221 are respectively communicated with a 3# sulfuric acid circulation tank 212 and a 4# sulfuric acid circulation tank 222, the 3# sulfuric acid circulation tank 212 is respectively communicated with a 3# sulfuric acid cooler 214, a reuse sulfuric acid ⑤ pipeline and an external sulfuric acid ⑥ pipeline through a 3# sulfuric acid circulation pump 213, the 3# sulfuric acid cooler 214 is communicated with the 3# sulfuric acid washing tower 211, the 4# sulfuric acid circulation tank 222 is respectively communicated with a 4# sulfuric acid cooler 224 and a 3# sulfuric acid washing tower 211 through a 4# sulfuric acid circulation pump 223, the 4# sulfuric acid cooler 224 is communicated with the 4# sulfuric acid washing tower 221, the 4# sulfuric acid washing tower 221 is respectively communicated with a 2# sulfuric acid cooler 124 and a 2# demister 231, and the 2# demister 231 is communicated with a.
The water washing tower adopted in the water washing device can be replaced by an alkali washing tower sprayed by alkali liquor, and correspondingly, the water washing circulating pool and the water washing circulating pump adopt an alkali liquor circulating pool and an alkali liquor circulating pump.
The method steps of the rare earth concentrate acidification tail gas treatment system are given as follows:
step 1, acidified tail gas treatment step
Firstly, acidified tail gas ① generated in an indirect-heating rare earth acidification rotary reactor enters a 1# sulfuric acid washing tower 111 of a first-stage pickling device, 92-96% concentrated sulfuric acid is used as a spray liquid to absorb and remove most of water vapor in acidified tail gas ①, the tail gas is discharged from the top of the tower to a 2# sulfuric acid washing tower 121, the sulfuric acid is diluted and falls into a 1# sulfuric acid circulation tank 112, and fuming sulfuric acid ② (H) is introduced at the same time2SO4More than 105%) to adjust the concentration of the sulfuric acid in the 1# sulfuric acid circulating pool 112 to 92-96%, pumping the sulfuric acid to a 1# sulfuric acid cooler 114 by a 1# sulfuric acid circulating pump 113, removing the heat generated in the process, dividing the sulfuric acid with the reduced temperature into two parts, wherein one part is used as a spray liquid and circulated back to a 1# sulfuric acid washing tower 111, and the other part is used as a 2# sulfuric acid washing tower 121.
The second step is that: the acidified tail gas passing through the 1# sulfuric acid washing tower 111 enters a 2# sulfuric acid washing tower 121, 92-96% concentrated sulfuric acid from a 1# sulfuric acid cooler 114 and self-circulating acid are used as spraying liquid to absorb and remove residual water in the tail gas, the tail gas is discharged from the top of the tower to a stage 1 absorber 131 of a gas absorption device, the diluted sulfuric acid with the concentration of 89-92% falls into a 2# sulfuric acid circulating tank 122, the sulfuric acid is removed from a 2# sulfuric acid cooler 124 by a 2# sulfuric acid circulating pump 123, heat generated in the process is removed, the sulfuric acid with the reduced temperature is divided into two parts, one part is used as the spraying liquid and circulated back to the 2# sulfuric acid washing tower 121, and the other part is used as a 4# sulfuric acid washing tower 221 of a second stage acid washing device.
Thirdly, the acidified tail gas removed with water by the 2# sulfuric acid washing tower 121 sequentially enters the tube pass of the serially connected 1-stage absorber 131 and 2-stage absorber 132, hydrofluoric acid spraying liquid enters from the top of the 1-stage absorber 131, liquid films are formed on the tube pass of the 1-stage absorber 131 and the 2-stage absorber 132, most HF gas in the acidified tail gas is dissolved in the liquid films, the rest tail gas is discharged from the 2-stage absorber 132 to the washing device 1# water washing tower 141, the concentrated hydrofluoric acid with the concentration of 30-34% falls into a hydrofluoric acid circulating pool 133, one part of the hydrofluoric acid circulating pump 134 is driven back to the 1-stage absorber 131, and the other part of the hydrofluoric acid circulating pump 134 is used as a product of hydrofluoric acid ③ to be.
Fourthly, the acidified tail gas discharged from the 2-stage absorber 132 sequentially passes through a 1# water washing tower 141, a 2# water washing tower 151 and a 3# water washing tower 161, the residual trace HF gas in the acidified tail gas is removed, and then is demisted 171 by a 1# demister, and is discharged after reaching standards from a 1# fan 181, a small amount of water ⑧ is added from a 3# water washing circulating pool 162, the circulating water passes through a 3# water washing circulating pump 163, one part of the circulating spray water is pumped back to the 3# water washing tower 161, one part of the circulating spray water is pumped back to the 2# water washing circulating pool 152, one part of the circulating spray water is pumped back to the 2# water washing tower 151 by a 2# water washing circulating pump 153, one part of the circulating spray water is pumped back to the 1# water washing tower 151, one part of the circulating spray water is pumped back to the 1# water washing tower 141 by a 1# water washing circulating pump 142, and one part of the circulating spray water is pumped.
Step 2, roasting tail gas treatment step
Firstly, roasting tail gas ④ generated in an indirect-heating rare earth roasting rotary reactor enters a 3# sulfuric acid washing tower 211 of a second-stage acid washing device, water vapor, sulfur trioxide gas and partial sulfuric acid vapor are removed through self-circulating 90-94% concentrated sulfuric acid and 89-93% concentrated sulfuric acid sprayed and absorbed by the 4# sulfuric acid washing tower 221, the sprayed concentrated sulfuric acid is discharged to the 4# sulfuric acid washing tower 221, the concentration of the sprayed concentrated sulfuric acid is 90-94%, the concentrated sulfuric acid falls into a 3# sulfuric acid circulating pool 212, a part of a 3# sulfuric acid circulating pump 213 is used for removing a 3# sulfuric acid cooler 214, heat generated in the process is removed, the sulfuric acid with the reduced temperature is used as spraying liquid and circulated back to the 3# sulfuric acid washing tower 211, the other part of the sulfuric acid is divided into recycled sulfuric acid ⑤, and the acid serving as the complex acid of the rare earth is returned to the indirect-heating rare earth.
The second step is that: roasting tail gas of a 3# sulfuric acid washing tower 211 of a second-stage acid washing device enters a 4# sulfuric acid washing tower 221, residual sulfuric acid steam in the tail gas is removed by absorption of 88.5-92.5% concentrated sulfuric acid from a 4# sulfuric acid cooler 224 and 88-92% concentrated sulfuric acid spraying liquid from a 2# sulfuric acid circulating pump 123, and the tail gas is discharged from a 2# fan 241 to an SO2 acid making device through a 2# demister demist 231. Concentrated sulfuric acid falls into a 4# sulfuric acid circulating tank 222, a part of the concentrated sulfuric acid is removed from a 4# sulfuric acid cooler 224 by a 4# sulfuric acid circulating pump 223, heat generated in the process is removed, the sulfuric acid with the reduced temperature is used as spray liquid to be circulated back to a 4# sulfuric acid washing tower 221, and the other part of the concentrated sulfuric acid is removed from a 3# sulfuric acid washing tower 211 to be used as spray liquid.
The invention is further illustrated by the following different examples.
Example 1
Taking rare earth concentrate smelting by an indirect heating type rotary reactor with the treatment capacity of 2t/h as an example, the acidified tail gas generated by the indirect heating type rare earth acidified rotary reactor is 180 ℃, and the flow composition is as follows:
| acidified tail gas component | Flow rate, kg/h | Mass fraction |
| H2O | 295.05 | 55.26％ |
| HF | 106.92 | 20.02％ |
| H2SO4 | 4.5 | 0.84％ |
| CO2 | 115.23 | 21.58％ |
| SO3 | 0.06 | 0.01％ |
| SiF4 | 12.21 | 2.29％ |
Roasting tail gas generated by the indirect-heating rare earth roasting rotary reactor is 350 ℃, and the flow composition is as follows:
the tail gas treatment method for rare earth concentrate acidizing roasting by adopting the system comprises the following steps:
introducing acidified tail gas of 180 ℃ into a No. 1 sulfuric acid washing tower, absorbing and removing most of water vapor in the acidified tail gas by using 94% concentrated sulfuric acid as a spray liquid, discharging the tail gas from the top of the tower to a No. 2 sulfuric acid washing tower, allowing the diluted 93% sulfuric acid to fall into a No. 1 sulfuric acid circulating pool, and simultaneously introducing oleum (H) into the tower2SO4More than 105%) to adjust the sulfuric acid concentration in the 1# sulfuric acid circulating pool to return to 94%, the sulfuric acid is driven by the 1# sulfuric acid circulating pump to remove heat generated in the removing process of the 1# sulfuric acid cooler, the sulfuric acid with the reduced temperature is divided into two parts, one part is taken as spray liquid and circulated to the 1# sulfuric acid washing tower, and the other part is taken to the 2# sulfuric acid washing tower.
The acidified tail gas passing through the 1# sulfuric acid washing tower enters a 2# sulfuric acid washing tower, 94% concentrated sulfuric acid from a 1# sulfuric acid cooler and self-circulating acid are used as spraying liquid to further absorb and remove residual water in the tail gas, the tail gas is discharged from the top of the tower to a 1-stage absorber, the diluted sulfuric acid with the concentration of 92.55% falls into a 2# sulfuric acid circulating pool, the diluted sulfuric acid is pumped to the 2# sulfuric acid cooler by a 2# sulfuric acid circulating pump to remove heat generated in the removing process, the sulfuric acid with the reduced temperature is divided into two parts, one part is used as the spraying liquid and circulated to the 2# sulfuric acid washing tower, and the other part is used for the 4# sulfuric acid washing tower.
The acidified tail gas removed by the 2# sulfuric acid washing tower sequentially enters a 1-stage absorber and a 2-stage absorber which are connected in series, hydrofluoric acid spraying liquid enters from the top of the 1-stage absorber, liquid films are formed on the tube passes of the 1-stage absorber and the 2-stage absorber, most HF gas in the acidified tail gas is dissolved in the liquid films, the rest tail gas is discharged from the 2-stage absorber to the 1# water washing tower, the concentrated 32.00% hydrofluoric acid falls into a hydrofluoric acid circulating pool, one part of the hydrofluoric acid circulating pump is used for returning to the 1-stage absorber, and the other part of the hydrofluoric acid circulating pump is used as a product hydrofluoric acid to be removed from a hydrofluoric acid.
And removing residual trace HF gas in the acidified tail gas from the acidified tail gas discharged from the 2-stage absorber through a 1# water washing tower, a 2# water washing tower and a 3# water washing tower in sequence, demisting through a 1# demister, and discharging from a 1# fan after reaching the standard. Adding a small amount of water into a 3# washing circulating pool, circulating water passes through a 3# washing circulating pump, one part of circulating spray water is taken as circulating spray water and pumped back to a 3# washing tower, one part of circulating spray water is pumped out of a 2# washing circulating pool, one part of circulating spray water is pumped back to the 2# washing tower through the 2# washing circulating pump, one part of circulating spray water is pumped out of a 1# washing circulating pool, one part of circulating spray water is pumped back to the 1# washing tower through the 1# washing circulating pump, and one part of circulating spray water is pumped out of a 1-level absorber.
Roasting tail gas generated in the indirect-heating rare earth roasting rotary reactor enters a 3# sulfuric acid washing tower, and is discharged to the 4# sulfuric acid washing tower after being sprayed and absorbed by self-circulating 92% concentrated sulfuric acid and 91% concentrated sulfuric acid from the 4# sulfuric acid washing tower to remove water vapor, sulfur trioxide gas and partial sulfuric acid vapor. The concentration of the sprayed concentrated sulfuric acid is 92 percent, the concentrated sulfuric acid falls into a 3# sulfuric acid circulating pool, a part of a 3# sulfuric acid circulating pump removes heat generated in the removing process of a 3# sulfuric acid cooler, the sulfuric acid with the temperature reduced is used as spraying liquid to circulate to a 3# sulfuric acid washing tower, the other part of the sulfuric acid is divided into sulfuric acid (recycled) which is used as the acid of the rare earth and returns to an indirect-heating rare earth acidification rotary reactor, and the sulfuric acid (discharged) is filtered and then discharged to a sulfuric acid storage tank.
The roasting tail gas passing through the 3# sulfuric acid washing tower enters the 4# sulfuric acid washing tower, 90.5% concentrated sulfuric acid from a 4# sulfuric acid cooler and 92.55% concentrated sulfuric acid spray liquid from a 2# sulfuric acid circulating pump are used for absorbing and removing residual sulfuric acid steam in the tail gas, then the tail gas is demisted by a 2# demister, and SO is discharged from a 2# fan2An acid making device. Concentrated sulfuric acid falls into a 4# sulfuric acid circulating tank, a part of a 4# sulfuric acid circulating pump removes heat generated in the removing process of a 4# sulfuric acid cooler, sulfuric acid with the temperature reduced serves as spraying liquid and circulates back to a 4# sulfuric acid washing tower, and the other part of the sulfuric acid removes a 3# sulfuric acid washing tower and serves as the spraying liquid.
The treated acidified tail gas has a temperature of 30 ℃, and the flow rate and composition are as follows:
| acidified tail gas component | Flow rate, kg/h | Mass fraction |
| H2O | 5.1 | 3.24％ |
| CO2 | 152.21 | 96.76％ |
| HF | ＜5mg/m3 | / |
The roasting tail gas after treatment has the following flow rate and composition at 30 ℃:
high SO2And (4) introducing the roasting tail gas with the content to an acid making device.
Meanwhile, 332.45kg/h of hydrofluoric acid with the concentration of 32.00 percent is recovered. Recovering 2 parts of sulfuric acid, wherein one part of sulfuric acid is recycled (removed from an indirect heating type rare earth acidification rotary reactor) at 1010.88kg/h, and the other part of sulfuric acid is recovered and stored at 1093.00kg/h, wherein the concentration of the sulfuric acid is 92.55%.
Example 2
Taking rare earth concentrate smelting by an indirect heating type rotary reactor with the treatment capacity of 2.78t/h as an example, the acidified tail gas generated by the indirect heating type rare earth acidified rotary reactor is 180 ℃, and the flow composition is as follows:
| acidified tail gas component | Flow rate, kg/h | Mass fraction |
| H2O | 396.22 | 53.89％ |
| HF | 162.53 | 22.10％ |
| H2SO4 | 6.24 | 0.85％ |
| CO2 | 153.22 | 20.84％ |
| SO3 | 0.08 | 0.01％ |
| SiF4 | 16.98 | 2.31％ |
Roasting tail gas generated by the indirect-heating rare earth roasting rotary reactor is 350 ℃, and the flow composition is as follows:
| roasting tail gas component | Flow rate, kg/h | Mass fraction |
| H2O | 291.05 | 20.42％ |
| H2SO4 | 577.17 | 40.49％ |
| SO3 | 400.78 | 28.12％ |
| SO2 | 126.31 | 8.86％ |
| O2 | 30.08 | 2.11％ |
The tail gas treatment method for rare earth concentrate acidizing roasting by adopting the system comprises the following steps:
introducing acidified tail gas of 180 ℃ into a No. 1 sulfuric acid washing tower, absorbing and removing most of water vapor in the acidified tail gas by using 94% concentrated sulfuric acid as a spray liquid, discharging the tail gas from the top of the tower to a No. 2 sulfuric acid washing tower, allowing the diluted 93% sulfuric acid to fall into a No. 1 sulfuric acid circulating pool, and simultaneously introducing oleum (H) into the tower2SO4More than 105%) to adjust the sulfuric acid concentration in the 1# sulfuric acid circulating pool to return to 94%, the sulfuric acid is driven by the 1# sulfuric acid circulating pump to remove heat generated in the removing process of the 1# sulfuric acid cooler, the sulfuric acid with the reduced temperature is divided into two parts, one part is taken as spray liquid and circulated to the 1# sulfuric acid washing tower, and the other part is taken to the 2# sulfuric acid washing tower.
The acidified tail gas passing through the 1# sulfuric acid washing tower enters a 2# sulfuric acid washing tower, 94% concentrated sulfuric acid from a 1# sulfuric acid cooler and self-circulating acid are used as spraying liquid to further absorb and remove residual water in the tail gas, the tail gas is discharged from the top of the tower to a 1-stage absorber, the diluted sulfuric acid with the concentration of 92.73% falls into a 2# sulfuric acid circulating tank, the diluted sulfuric acid is driven to the 2# sulfuric acid cooler by a 2# sulfuric acid circulating pump to remove heat generated in the process, the sulfuric acid with the reduced temperature is divided into two parts, one part is used as the spraying liquid and circulated to the 2# sulfuric acid washing tower, and the other part is used for the 4# sulfuric acid washing tower.
The acidified tail gas removed by the 2# sulfuric acid washing tower sequentially enters a 1-stage absorber and a 2-stage absorber which are connected in series, hydrofluoric acid spraying liquid enters from the top of the 1-stage absorber, liquid films are formed on the tube passes of the 1-stage absorber and the 2-stage absorber, most HF gas in the acidified tail gas is dissolved in the liquid films, the residual tail gas is discharged from the 2-stage absorber to the 1# water washing tower, the concentrated hydrofluoric acid with the concentration of 30.57 percent falls into a hydrofluoric acid circulating pool, one part of the hydrofluoric acid circulating pump is used for returning to the 1-stage absorber, and the other part of the hydrofluoric acid circulating pump is used as a product hydrofluoric acid to be removed.
And removing residual trace HF gas in the acidified tail gas from the acidified tail gas discharged from the 2-stage absorber through a 1# water washing tower, a 2# water washing tower and a 3# water washing tower in sequence, demisting through a 1# demister, and discharging from a 1# fan after reaching the standard. Adding a small amount of water into a 3# washing circulating pool, circulating water passes through a 3# washing circulating pump, one part of circulating spray water is taken as circulating spray water and pumped back to a 3# washing tower, one part of circulating spray water is pumped out of a 2# washing circulating pool, one part of circulating spray water is pumped back to the 2# washing tower through the 2# washing circulating pump, one part of circulating spray water is pumped out of a 1# washing circulating pool, one part of circulating spray water is pumped back to the 1# washing tower through the 1# washing circulating pump, and one part of circulating spray water is pumped out of a 1-level absorber.
Roasting tail gas generated in the indirect-heating rare earth roasting rotary reactor enters a 3# sulfuric acid washing tower, and is discharged to the 4# sulfuric acid washing tower after being sprayed and absorbed by self-circulating 92% concentrated sulfuric acid and 91% concentrated sulfuric acid from the 4# sulfuric acid washing tower to remove water vapor, sulfur trioxide gas and partial sulfuric acid vapor. The concentration of the sprayed concentrated sulfuric acid is 92 percent, the concentrated sulfuric acid falls into a 3# sulfuric acid circulating pool, a part of a 3# sulfuric acid circulating pump removes heat generated in the removing process of a 3# sulfuric acid cooler, the sulfuric acid with the temperature reduced is used as spraying liquid to circulate to a 3# sulfuric acid washing tower, the other part of the sulfuric acid is divided into sulfuric acid (recycled) which is used as the acid of the rare earth and returns to an indirect-heating rare earth acidification rotary reactor, and the sulfuric acid (discharged) is filtered and then discharged to a sulfuric acid storage tank.
The roasting tail gas passing through the 3# sulfuric acid washing tower enters the 4# sulfuric acid washing tower, 90.5% concentrated sulfuric acid from a 4# sulfuric acid cooler and 92.73% concentrated sulfuric acid spray liquid from a 2# sulfuric acid circulating pump are used for absorbing and removing residual sulfuric acid steam in the tail gas, then the tail gas is demisted by a 2# demister, and SO is discharged from a 2# fan2An acid making device. Concentrated sulfuric acid falls into a 4# sulfuric acid circulating tank, a part of a 4# sulfuric acid circulating pump removes heat generated in the removing process of a 4# sulfuric acid cooler, sulfuric acid with the temperature reduced serves as spraying liquid and circulates back to a 4# sulfuric acid washing tower, and the other part of the sulfuric acid removes a 3# sulfuric acid washing tower and serves as the spraying liquid.
The treated acidified tail gas has a temperature of 30 ℃, and the flow rate and composition are as follows:
| acidified tail gas component | Flow rate, kg/h | Mass fraction |
| H2O | 5.1 | 3.24％ |
| CO2 | 152.21 | 96.76％ |
| HF | ＜5mg/m3 | / |
The roasting tail gas after treatment has the following flow rate and composition at 30 ℃:
| roasting tail gas component | Flow rate, kg/h | Mass fraction |
| H2SO4 | 0.13 | 0.08％ |
| SO2 | 125.02 | 80.59％ |
| O2 | 29.98 | 19.33％ |
High SO2And (4) introducing the roasting tail gas with the content to an acid making device.
Meanwhile, 529.00kg/h of hydrofluoric acid with the concentration of 30.57 percent is recovered. Recovering 2 parts of sulfuric acid, wherein one part of sulfuric acid is recycled (removed from an indirect rare earth acidification rotary reactor) at 1391.22kg/h, and the other part of sulfuric acid is recovered and stored at 1519.11kg/h, wherein the concentration of the sulfuric acid is 92.73 percent.
Example 3
Taking rare earth concentrate smelting by an indirect heating type rotary reactor with the treatment capacity of 3t/h as an example, the acidified tail gas generated by the indirect heating type rare earth acidified rotary reactor is 180 ℃, and the flow composition is as follows:
| acidified tail gas component | Flow rate, kg/h | Mass fraction |
| H2O | 437.57 | 55.92％ |
| HF | 165.39 | 21.14％ |
| H2SO4 | 6.73 | 0.86％ |
| CO2 | 155.34 | 19.85％ |
| SO3 | 0.08 | 0.01％ |
| SiF4 | 17.32 | 2.21％ |
Roasting tail gas generated by the indirect-heating rare earth roasting rotary reactor is 350 ℃, and the flow composition is as follows:
| roasting tail gas component | Flow rate, kg/h | Mass fraction |
| H2O | 334.08 | 21.72％ |
| H2SO4 | 602.85 | 39.19％ |
| SO3 | 422.49 | 27.47％ |
| SO2 | 146.3 | 9.51％ |
| O2 | 32.46 | 2.11％ |
The tail gas treatment method for rare earth concentrate acidizing roasting by adopting the system comprises the following steps:
introducing acidified tail gas of 180 ℃ into a No. 1 sulfuric acid washing tower, absorbing and removing most of water vapor in the acidified tail gas by using 92% concentrated sulfuric acid as a spraying liquid, discharging the tail gas from the top of the tower to the No. 2 sulfuric acid washing tower, and allowing diluted 91% sulfuric acid to fall into the No. 1 sulfuric acid washing tower1# sulfuric acid circulating tank, and fuming sulfuric acid (H) is introduced at the same time2SO4More than 105%) to adjust the sulfuric acid concentration in the 1# sulfuric acid circulating pool to return to 92%, the sulfuric acid is driven by the 1# sulfuric acid circulating pump to remove heat generated in the removing process of the 1# sulfuric acid cooler, the sulfuric acid with the reduced temperature is divided into two parts, one part is taken as spray liquid and circulated to the 1# sulfuric acid washing tower, and the other part is taken to the 2# sulfuric acid washing tower.
The acidified tail gas passing through the 1# sulfuric acid washing tower enters a 2# sulfuric acid washing tower, 92% concentrated sulfuric acid from a 1# sulfuric acid cooler and self-circulating acid are used as spraying liquid to further absorb and remove residual water in the tail gas, the tail gas is discharged from the top of the tower to a 1-stage absorber, the diluted sulfuric acid with the concentration of 90.33% falls into a 2# sulfuric acid circulating tank, the sulfuric acid is driven to the 2# sulfuric acid cooler by a 2# sulfuric acid circulating pump to remove heat generated in the process, the sulfuric acid with the reduced temperature is divided into two parts, one part is used as the spraying liquid and circulated to the 2# sulfuric acid washing tower, and the other part is used for the 4# sulfuric acid washing tower.
The acidified tail gas removed by the 2# sulfuric acid washing tower sequentially enters a 1-stage absorber and a 2-stage absorber which are connected in series, hydrofluoric acid spraying liquid enters from the top of the 1-stage absorber, liquid films are formed on the tube passes of the 1-stage absorber and the 2-stage absorber, most HF gas in the acidified tail gas is dissolved in the liquid films, the rest tail gas is discharged from the 2-stage absorber to the 1# water washing tower, the concentrated 31.00% hydrofluoric acid falls into a hydrofluoric acid circulating pool, one part of the hydrofluoric acid circulating pump is used for returning to the 1-stage absorber, and the other part of the hydrofluoric acid circulating pump is used as a product hydrofluoric acid to be removed from a hydrofluoric acid.
And removing residual trace HF gas in the acidified tail gas from the acidified tail gas discharged from the 2-stage absorber through a 1# water washing tower, a 2# water washing tower and a 3# water washing tower in sequence, demisting through a 1# demister, and discharging from a 1# fan after reaching the standard. Adding a small amount of water into a 3# washing circulating pool, circulating water passes through a 3# washing circulating pump, one part of circulating spray water is taken as circulating spray water and pumped back to a 3# washing tower, one part of circulating spray water is pumped out of a 2# washing circulating pool, one part of circulating spray water is pumped back to the 2# washing tower through the 2# washing circulating pump, one part of circulating spray water is pumped out of a 1# washing circulating pool, one part of circulating spray water is pumped back to the 1# washing tower through the 1# washing circulating pump, and one part of circulating spray water is pumped out of a 1-level absorber.
Roasting tail gas generated in the indirect-heating rare earth roasting rotary reactor enters a 3# sulfuric acid washing tower, and is discharged to the 4# sulfuric acid washing tower after being sprayed and absorbed by self-circulating 92% concentrated sulfuric acid and 91% concentrated sulfuric acid from the 4# sulfuric acid washing tower to remove water vapor, sulfur trioxide gas and partial sulfuric acid vapor. The concentration of the sprayed concentrated sulfuric acid is 92 percent, the concentrated sulfuric acid falls into a 3# sulfuric acid circulating pool, a part of a 3# sulfuric acid circulating pump removes heat generated in the removing process of a 3# sulfuric acid cooler, the sulfuric acid with the temperature reduced is used as spraying liquid to circulate to a 3# sulfuric acid washing tower, the other part of the sulfuric acid is divided into sulfuric acid (recycled) which is used as the acid of the rare earth and returns to an indirect-heating rare earth acidification rotary reactor, and the sulfuric acid (discharged) is filtered and then discharged to a sulfuric acid storage tank.
The roasting tail gas passing through the 3# sulfuric acid washing tower enters the 4# sulfuric acid washing tower, 90.5% concentrated sulfuric acid from a 4# sulfuric acid cooler and 90.33% concentrated sulfuric acid spray liquid from a 2# sulfuric acid circulating pump are used for absorbing and removing residual sulfuric acid steam in the tail gas, then the tail gas is demisted by a 2# demister, and SO is discharged from a 2# fan2An acid making device. Concentrated sulfuric acid falls into a 4# sulfuric acid circulating tank, a part of a 4# sulfuric acid circulating pump removes heat generated in the removing process of a 4# sulfuric acid cooler, sulfuric acid with the temperature reduced serves as spraying liquid and circulates back to a 4# sulfuric acid washing tower, and the other part of the sulfuric acid removes a 3# sulfuric acid washing tower and serves as the spraying liquid.
The treated acidified tail gas has a temperature of 30 ℃, and the flow rate and composition are as follows:
| acidified tail gas component | Flow rate, kg/h | Mass fraction |
| H2O | 5.1 | 3.24％ |
| CO2 | 152.21 | 96.76％ |
| HF | ＜5mg/m3 | / |
The roasting tail gas after treatment has the following flow rate and composition at 30 ℃:
| roasting tail gas component | Flow rate, kg/h | Mass fraction |
| H2SO4 | 0.13 | 0.08％ |
| SO2 | 125.02 | 80.59％ |
| O2 | 29.98 | 19.33％ |
High SO2And (4) introducing the roasting tail gas with the content to an acid making device.
Meanwhile, 530.85kg/h of hydrofluoric acid with the concentration of 31.00 percent is recovered. Recovering 2 parts of sulfuric acid, wherein one part of sulfuric acid is recycled (removed from an indirect rare earth acidification rotary reactor) at 1511.32kg/h, and the other part of sulfuric acid is recovered and stored at 1639.33kg/h, wherein the concentration of the sulfuric acid is 90.33%.
Example 4
Taking rare earth concentrate smelting by an indirect heating type rotary reactor with the treatment capacity of 3.3t/h as an example, the acidified tail gas generated by the indirect heating type rare earth acidified rotary reactor is 180 ℃, and the flow composition is as follows:
| acidified tail gas component | Flow rate, kg/h | Mass fraction |
| H2O | 470.33 | 55.81％ |
| HF | 172.93 | 20.52％ |
| H2SO4 | 7.4 | 0.88％ |
| CO2 | 171.87 | 20.39％ |
| SO3 | 0.094 | 0.01％ |
| SiF4 | 20.15 | 2.39％ |
Roasting tail gas generated by the indirect-heating rare earth roasting rotary reactor is 350 ℃, and the flow composition is as follows:
| roasting tail gas component | Flow rate, kg/h | Mass fraction |
| H2O | 335.49 | 19.95％ |
| H2SO4 | 695.12 | 41.33％ |
| SO3 | 465.74 | 27.69％ |
| SO2 | 149.93 | 8.91％ |
| O2 | 35.7 | 2.12％ |
The tail gas treatment method for rare earth concentrate acidizing roasting by adopting the system comprises the following steps:
introducing acidified tail gas of 180 ℃ into a No. 1 sulfuric acid washing tower, absorbing and removing most of water vapor in the acidified tail gas by using 96% concentrated sulfuric acid as a spray liquid, discharging the tail gas from the top of the tower to a No. 2 sulfuric acid washing tower, allowing diluted 94.6% sulfuric acid to fall into a No. 1 sulfuric acid circulating pool, and simultaneously introducing oleum (H) into the tower2SO4More than 105%) to adjust the sulfuric acid concentration in the 1# sulfuric acid circulating pool to return to 96%, and the sulfuric acid is driven by the 1# sulfuric acid circulating pump to remove heat generated in the removing process of the 1# sulfuric acid cooler, and the sulfuric acid with the reduced temperature is divided into two parts, wherein one part is taken as a spray liquid and circulated to the 1# sulfuric acid washing tower, and the other part is taken to the 2# sulfuric acid washing tower.
The acidified tail gas passing through the 1# sulfuric acid washing tower enters a 2# sulfuric acid washing tower, 96% concentrated sulfuric acid from a 1# sulfuric acid cooler and self-circulating acid are used as spraying liquid to further absorb and remove residual water in the tail gas, the tail gas is discharged from the top of the tower to a 1-stage absorber, the diluted sulfuric acid with the concentration of 93.8% falls into a 2# sulfuric acid circulating tank, the sulfuric acid is driven to the 2# sulfuric acid cooler by a 2# sulfuric acid circulating pump to remove heat generated in the process, the sulfuric acid with the reduced temperature is divided into two parts, one part is used as the spraying liquid and circulated to the 2# sulfuric acid washing tower, and the other part is used for the 4# sulfuric acid washing tower.
The acidified tail gas removed by the 2# sulfuric acid washing tower sequentially enters a 1-stage absorber and a 2-stage absorber which are connected in series, hydrofluoric acid spraying liquid enters from the top of the 1-stage absorber, liquid films are formed on the tube passes of the 1-stage absorber and the 2-stage absorber, most HF gas in the acidified tail gas is dissolved in the liquid films, the rest tail gas is discharged from the 2-stage absorber to the 1# water washing tower, the concentrated 32.30% hydrofluoric acid falls into a hydrofluoric acid circulating pool, one part of the hydrofluoric acid circulating pump is used for returning to the 1-stage absorber, and the other part of the hydrofluoric acid circulating pump is used as a product hydrofluoric acid to be removed from a hydrofluoric acid.
And removing residual trace HF gas in the acidified tail gas from the acidified tail gas discharged from the 2-stage absorber through a 1# water washing tower, a 2# water washing tower and a 3# water washing tower in sequence, demisting through a 1# demister, and discharging from a 1# fan after reaching the standard. Adding a small amount of water into a 3# washing circulating pool, circulating water passes through a 3# washing circulating pump, one part of circulating spray water is taken as circulating spray water and pumped back to a 3# washing tower, one part of circulating spray water is pumped out of a 2# washing circulating pool, one part of circulating spray water is pumped back to the 2# washing tower through the 2# washing circulating pump, one part of circulating spray water is pumped out of a 1# washing circulating pool, one part of circulating spray water is pumped back to the 1# washing tower through the 1# washing circulating pump, and one part of circulating spray water is pumped out of a 1-level absorber.
Roasting tail gas generated in the indirect-heating rare earth roasting rotary reactor enters a 3# sulfuric acid washing tower, and is discharged out of the 4# sulfuric acid washing tower after self-circulating 94.3% concentrated sulfuric acid and 93.4% concentrated sulfuric acid from the 4# sulfuric acid washing tower are sprayed and absorbed to remove water vapor, sulfur trioxide gas and partial sulfuric acid vapor. The concentration of the sprayed concentrated sulfuric acid is 94.3 percent, the concentrated sulfuric acid falls into a 3# sulfuric acid circulating pool, a part of a 3# sulfuric acid circulating pump removes heat generated in the process of removing the 3# sulfuric acid cooler, the sulfuric acid with the temperature reduced is used as spraying liquid to circulate to a 3# sulfuric acid washing tower, the other part of the sulfuric acid is divided into sulfuric acid (recycled) which is used as the acid of the rare earth and returns to an indirect-type rare earth acidification rotary reactor, and the sulfuric acid (discharged) is filtered and then discharged to a sulfuric acid storage tank.
The roasting tail gas passing through the 3# sulfuric acid washing tower enters the 4# sulfuric acid washing tower, and is absorbed by 93.1% concentrated sulfuric acid from a 4# sulfuric acid cooler and 93.8% concentrated sulfuric acid spray liquid from a 2# sulfuric acid circulating pump to remove residual sulfuric acid vapor in the tail gas, and then is demisted by a 2# demister, and SO is discharged from a 2# fan2An acid making device. Concentrated sulfuric acid falls into a 4# sulfuric acid circulating tank, a part of a 4# sulfuric acid circulating pump removes heat generated in the removing process of a 4# sulfuric acid cooler, sulfuric acid with the temperature reduced serves as spraying liquid and circulates back to a 4# sulfuric acid washing tower, and the other part of the sulfuric acid removes a 3# sulfuric acid washing tower and serves as the spraying liquid.
The treated acidified tail gas has a temperature of 30 ℃, and the flow rate and composition are as follows:
| acidified tail gas component | Flow rate, kg/h | Mass fraction |
| H2O | 5.1 | 3.24％ |
| CO2 | 152.21 | 96.76％ |
| HF | ＜5mg/m3 | / |
The roasting tail gas after treatment has the following flow rate and composition at 30 ℃:
| roasting tail gas component | Flow rate, kg/h | Mass fraction |
| H2SO4 | 0.13 | 0.08％ |
| SO2 | 125.02 | 80.59％ |
| O2 | 29.98 | 19.33％ |
High SO2And (4) introducing the roasting tail gas with the content to an acid making device.
Meanwhile, 532.71kg/h of hydrofluoric acid with the concentration of 32.30 percent is recovered. The sulfuric acid is recovered and divided into 2 parts, one part of the sulfuric acid is recycled (removed from an indirect rare earth acidification rotary reactor) for 1651.45kg/h, and the other part of the sulfuric acid is recovered and stored for 1803.26kg/h, wherein the concentration of the sulfuric acid is 93.8 percent.
Example 5
Taking rare earth concentrate smelting by an indirect heating type rotary reactor with the treatment capacity of 3.5t/h as an example, the acidified tail gas generated by the indirect heating type rare earth acidified rotary reactor is 180 ℃, and the flow composition is as follows:
| acidified tail gas component | Flow rate, kg/h | Mass fraction |
| H2O | 476.35 | 52.78％ |
| HF | 204.62 | 22.67％ |
| H2SO4 | 7.25 | 0.80％ |
| CO2 | 192.9 | 21.37％ |
| SO3 | 0.1 | 0.01％ |
| SiF4 | 21.37 | 2.37％ |
Roasting tail gas generated by the indirect-heating rare earth roasting rotary reactor is 350 ℃, and the flow composition is as follows:
| roasting tail gas component | Flow rate, kg/h | Mass fraction |
| H2O | 366.42 | 20.42％ |
| H2SO4 | 726.65 | 40.49％ |
| SO3 | 504.57 | 28.12％ |
| SO2 | 159.02 | 8.86％ |
| O2 | 37.87 | 2.11％ |
The tail gas treatment method for rare earth concentrate acidizing roasting by adopting the system comprises the following steps:
introducing acidified tail gas of 180 ℃ into a No. 1 sulfuric acid washing tower, absorbing and removing most of water vapor in the acidified tail gas by using 93% concentrated sulfuric acid as a spray liquid, discharging the tail gas from the top of the tower to the No. 2 sulfuric acid washing tower, allowing diluted 92.2% sulfuric acid to fall into a No. 1 sulfuric acid circulating pool, and simultaneously introducing oleum (H) into the tower2SO4More than 105%) to adjust the sulfuric acid concentration in the 1# sulfuric acid circulating pool to return to 93%, the sulfuric acid is driven by a 1# sulfuric acid circulating pump to remove heat generated in the process of removing the sulfuric acid by a 1# sulfuric acid cooler, the sulfuric acid with the reduced temperature is divided into two parts, one part is taken as a spray liquid to be circulated to a 1# sulfuric acid washing tower, and the other part is taken as a 2# sulfuric acid washing tower.
The acidified tail gas passing through the 1# sulfuric acid washing tower enters a 2# sulfuric acid washing tower, 93% concentrated sulfuric acid from a 1# sulfuric acid cooler and self-circulating acid are used as spraying liquid to further absorb and remove residual water in the tail gas, the tail gas is discharged from the top of the tower to a 1-stage absorber, the diluted sulfuric acid with the concentration of 91.22% falls into a 2# sulfuric acid circulating pool, the sulfuric acid is pumped to the 2# sulfuric acid cooler by a 2# sulfuric acid circulating pump to remove heat generated in the removing process, the sulfuric acid with the reduced temperature is divided into two parts, one part is used as the spraying liquid and circulated to the 2# sulfuric acid washing tower, and the other part is used for the 4# sulfuric acid washing tower.
The acidified tail gas removed by the 2# sulfuric acid washing tower sequentially enters a 1-stage absorber and a 2-stage absorber which are connected in series, hydrofluoric acid spraying liquid enters from the top of the 1-stage absorber, liquid films are formed on the tube passes of the 1-stage absorber and the 2-stage absorber, most HF gas in the acidified tail gas is dissolved in the liquid films, the rest tail gas is discharged from the 2-stage absorber to the 1# water washing tower, the concentrated 31.76% hydrofluoric acid falls into a hydrofluoric acid circulating pool, one part of the hydrofluoric acid circulating pump is used for returning to the 1-stage absorber, and the other part of the hydrofluoric acid circulating pump is used as a product hydrofluoric acid to be removed from a hydrofluoric acid.
And removing residual trace HF gas in the acidified tail gas from the acidified tail gas discharged from the 2-stage absorber through a 1# water washing tower, a 2# water washing tower and a 3# water washing tower in sequence, demisting through a 1# demister, and discharging from a 1# fan after reaching the standard. Adding a small amount of water into a 3# washing circulating pool, circulating water passes through a 3# washing circulating pump, one part of circulating spray water is taken as circulating spray water and pumped back to a 3# washing tower, one part of circulating spray water is pumped out of a 2# washing circulating pool, one part of circulating spray water is pumped back to the 2# washing tower through the 2# washing circulating pump, one part of circulating spray water is pumped out of a 1# washing circulating pool, one part of circulating spray water is pumped back to the 1# washing tower through the 1# washing circulating pump, and one part of circulating spray water is pumped out of a 1-level absorber.
Roasting tail gas generated in the indirect-heating rare earth roasting rotary reactor enters a 3# sulfuric acid washing tower, and is discharged to the 4# sulfuric acid washing tower after being sprayed and absorbed by self-circulating 92% concentrated sulfuric acid and 91% concentrated sulfuric acid from the 4# sulfuric acid washing tower to remove water vapor, sulfur trioxide gas and partial sulfuric acid vapor. The concentration of the sprayed concentrated sulfuric acid is 92 percent, the concentrated sulfuric acid falls into a 3# sulfuric acid circulating pool, a part of a 3# sulfuric acid circulating pump removes heat generated in the removing process of a 3# sulfuric acid cooler, the sulfuric acid with the temperature reduced is used as spraying liquid to circulate to a 3# sulfuric acid washing tower, the other part of the sulfuric acid is divided into sulfuric acid (recycled) which is used as the acid of the rare earth and returns to an indirect-heating rare earth acidification rotary reactor, and the sulfuric acid (discharged) is filtered and then discharged to a sulfuric acid storage tank.
The roasting tail gas passing through the 3# sulfuric acid washing tower enters the 4# sulfuric acid washing tower, 90.5% concentrated sulfuric acid from a 4# sulfuric acid cooler and 91.22% concentrated sulfuric acid spray liquid from a 2# sulfuric acid circulating pump are used for absorbing and removing residual sulfuric acid steam in the tail gas, then the tail gas is demisted by a 2# demister, and SO is discharged from a 2# fan2An acid making device. Concentrated sulfuric acid falls into a 4# sulfuric acid circulating tank, and a part of a 4# sulfuric acid circulating pump is used for removing a 4# sulfuric acid cooler to produce in the processThe generated heat and the sulfuric acid with the reduced temperature are taken as spraying liquid to be circulated to a 4# sulfuric acid washing tower, and the other part is removed from the 3# sulfuric acid washing tower to be taken as the spraying liquid.
The treated acidified tail gas has a temperature of 30 ℃, and the flow rate and composition are as follows:
| acidified tail gas component | Flow rate, kg/h | Mass fraction |
| H2O | 5.1 | 3.24％ |
| CO2 | 152.21 | 96.76％ |
| HF | ＜5mg/m3 | / |
The roasting tail gas after treatment has the following flow rate and composition at 30 ℃:
| roasting tail gas component | Flow rate, kg/h | Mass fraction |
| H2SO4 | 0.13 | 0.08％ |
| SO2 | 125.02 | 80.59％ |
| O2 | 29.98 | 19.33％ |
High SO2And (4) introducing the roasting tail gas with the content to an acid making device.
Meanwhile, 614.05kg/h of hydrofluoric acid with the concentration of 31.76 percent is recovered. Recovering 2 parts of sulfuric acid, wherein one part of sulfuric acid is recycled (removed from an indirect heating type rare earth acidification rotary reactor) at 1731.50kg/h, and the other part of sulfuric acid is recovered and stored at 1890.55kg/h, wherein the concentration of the sulfuric acid is 91.22%.
By the above examples, a minimum concentration of 30.57% hydrofluoric acid and a minimum concentration of 90.33% sulfuric acid were obtained, which is superior to the prior art.
The present invention is not limited to the above-mentioned embodiments, and based on the technical solutions disclosed in the present invention, those skilled in the art can make some substitutions and modifications to some technical features without creative efforts according to the disclosed technical contents, and these substitutions and modifications are all within the protection scope of the present invention.
Claims (10)
1. A rare earth concentrate acidification tail gas treatment system based on an indirect-heating type rotary reactor is characterized by comprising at least two stages of pickling devices, two stages of gas absorption devices, two stages of washing devices and two demisting devices;
in the pickling device, a first-stage pickling device is communicated with an acidified tail gas pipeline, all stages of the first-stage pickling device are sequentially communicated, and a final-stage pickling device is respectively communicated with a gas absorption device and a second-stage pickling device; the gas absorption device is respectively communicated with the hydrofluoric acid pipeline and the water washing device;
the second-stage pickling device is communicated with the roasting tail gas pipeline, all stages of the second-stage pickling device are sequentially communicated, and the final-stage pickling device is communicated with the demisting device;
the washing devices at all levels are sequentially communicated, the last-stage washing device is respectively communicated with the demisting device and the water pipeline, the washing circulating pumps of the washing devices at all levels are sequentially communicated with the upper-stage water circulating pump, and the first-stage washing circulating pump is communicated with the first-stage gas absorption device.
2. The rare earth concentrate acidification tail gas treatment system based on the indirect-heating type rotary reactor as claimed in claim 1, wherein each stage of pickling device comprises a sulfuric acid washing tower, a sulfuric acid circulating tank, a sulfuric acid circulating pump and a sulfuric acid cooler, and the sulfuric acid washing tower, the sulfuric acid circulating tank, the sulfuric acid circulating pump, the sulfuric acid cooler and the sulfuric acid washing tower are sequentially and circularly communicated.
3. The rare earth concentrate acidification tail gas treatment system based on the indirect-heating type rotary reactor as claimed in claim 2, wherein the first stage sulfuric acid washing tower is communicated with the sulfuric acid washing towers in sequence from the top; the final stage sulfuric acid washing tower is communicated to a gas absorption device from the top; the sulfuric acid cooler of the final stage acid washing device of the first stage acid washing device is communicated to the sulfuric acid washing tower of the final stage acid washing device of the second stage acid washing device.
4. The rare earth concentrate acidification tail gas treatment system based on the indirect-heating type rotary reactor as claimed in claim 1, wherein the second stage sulfuric acid washing tower is communicated with the sulfuric acid washing towers in sequence from the top; the final stage sulfuric acid washing tower is communicated to a demister from the top.
5. The rare earth concentrate acidizing tail gas treatment system based on the indirect-heating type rotary reactor as claimed in claim 1, wherein the gas absorption device comprises a plurality of stages of gas absorbers which are sequentially communicated, the last stage of gas absorbers are respectively communicated with a hydrofluoric acid circulating pool, and the hydrofluoric acid circulating pool is communicated with a hydrofluoric acid pipeline and the first stage of gas absorbers through a hydrofluoric acid circulating pump.
6. The rare earth concentrate acidizing tail gas treatment system based on the indirect-heating type rotary reactor as claimed in claim 1, wherein the water washing devices comprise water washing towers, water washing circulation tanks and water washing circulation pumps, and the water washing towers, the water washing circulation tanks, the water washing circulation pumps and the water washing towers are sequentially communicated in a circulation mode.
7. The rare earth concentrate acidification tail gas treatment system based on the indirect-heating type rotary reactor as claimed in claim 6, wherein the water washing tower is replaced by an alkali washing tower sprayed with alkali liquor.
8. The rare earth concentrate acidification tail gas treatment system based on the indirect-heating type rotary reactor as claimed in claim 1, wherein each stage of water washing tower is communicated with the secondary water washing tower from the top; the last stage water washing tower is communicated to the demister from the top.
9. The rare earth concentrate acidizing tail gas treatment system based on the indirect-heating type rotary reactor of claim 1, wherein the demister is communicated with a tail gas purifying pipeline through a fan to discharge or is communicated with a sulfur dioxide acid making device.
10. A rare earth concentrate acidification tail gas treatment method of any one of the systems of claims 1 to 9, characterized by comprising the following steps:
and (3) acidizing tail gas treatment:
1) spraying 92-96% concentrated sulfuric acid spray liquid when acidified tail gas enters a 1# sulfuric acid washing tower of a first-stage acid washing device, discharging the tail gas to a 2# sulfuric acid washing tower, diluting the diluted sulfuric acid to fall into a 1# sulfuric acid circulating tank, introducing fuming sulfuric acid into the 1# sulfuric acid circulating tank, pumping the fuming sulfuric acid into a 1# sulfuric acid cooler, circulating one part of the fuming sulfuric acid to the 1# sulfuric acid washing tower, and removing the other part of the fuming sulfuric acid to the 2# sulfuric acid washing tower;
2) the acidified tail gas passing through the 1# sulfuric acid washing tower enters a 2# sulfuric acid washing tower, concentrated sulfuric acid and self-circulation acid of a 1# sulfuric acid cooler are used for spraying, the tail gas is discharged from the top of the tower and enters a 1-stage absorber of a gas absorption device, 89-92% diluted sulfuric acid falls into a 2# sulfuric acid circulation tank and is pumped into the 2# sulfuric acid cooler, one part of the sulfuric acid is circulated to the 2# sulfuric acid washing tower, and the other part of the sulfuric acid is sent to a 4# sulfuric acid washing tower of a second-stage acid washing device;
3) acidified tail gas and hydrofluoric acid spray liquid of a No. 2 sulfuric acid washing tower sequentially enter a No. 1 absorber and a No. 2 absorber of a gas absorption device, liquid films are formed on tube passes of the No. 1 absorber and the No. 2 absorber, the residual tail gas is discharged to the No. 1 water washing tower of the water washing device, concentrated hydrofluoric acid with the concentration of 30-34% falls into a hydrofluoric acid circulating pool, one part of the concentrated hydrofluoric acid is pumped into the No. 1 absorber, and the other part of the concentrated hydrofluoric acid is pumped to a hydrofluoric acid storage tank;
4) the acidified tail gas discharged by the 2-stage absorber sequentially passes through the three-stage water washing tower, demisted by the 1# demister 171 and discharged from the 1# fan after reaching the standard; pumping a small amount of water back to a 3# water washing tower, a 2# water washing tower and a 1# water washing tower respectively, and pumping the other part of water back to a 2# water washing circulating pool, a 1# water washing circulating pool and a 1-stage absorber respectively;
roasting tail gas treatment:
1) after the roasting tail gas enters a 3# sulfuric acid washing tower of a second-stage acid washing device, the roasting tail gas is sprayed and discharged to the 4# sulfuric acid washing tower through self-circulating 90-94% concentrated sulfuric acid and 89-93% concentrated sulfuric acid from the 4# sulfuric acid washing tower; the sprayed concentrated sulfuric acid falls into a 3# sulfuric acid circulating pool, one part of the concentrated sulfuric acid is removed from a 3# sulfuric acid cooler to a 3# sulfuric acid washing tower, the other part of the concentrated sulfuric acid is divided into recycled sulfuric acid and discharged sulfuric acid, the recycled sulfuric acid returns to an indirect-heating rare earth acidification rotary reactor, and the discharged sulfuric acid is filtered and then discharged to a sulfuric acid storage tank;
2) the roasting tail gas of the 3# sulfuric acid washing tower of the second-stage acid washing device enters a 4# sulfuric acid washing tower, is sprayed by 88.5-92.5% concentrated sulfuric acid from a 4# sulfuric acid cooler and 88-92% concentrated sulfuric acid spray liquid from a 2# sulfuric acid circulating pump, and is demisted by a 2# demister, and is discharged from a 2# fan to an SO2 acid making device;
concentrated sulfuric acid falls into a 4# sulfuric acid circulating pool, one part of the concentrated sulfuric acid is removed from a 4# sulfuric acid cooler, the cooled sulfuric acid is circulated back to a 4# sulfuric acid washing tower, and the other part of the concentrated sulfuric acid is removed from a 3# sulfuric acid washing tower.
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