CN117268125A - Method for purifying and treating neodymium iron boron waste roasting waste gas - Google Patents
Method for purifying and treating neodymium iron boron waste roasting waste gas Download PDFInfo
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- CN117268125A CN117268125A CN202311566419.9A CN202311566419A CN117268125A CN 117268125 A CN117268125 A CN 117268125A CN 202311566419 A CN202311566419 A CN 202311566419A CN 117268125 A CN117268125 A CN 117268125A
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- 238000000034 method Methods 0.000 title claims abstract description 44
- 239000002699 waste material Substances 0.000 title claims abstract description 33
- 239000002912 waste gas Substances 0.000 title claims abstract description 29
- 229910001172 neodymium magnet Inorganic materials 0.000 title claims abstract description 28
- QJVKUMXDEUEQLH-UHFFFAOYSA-N [B].[Fe].[Nd] Chemical compound [B].[Fe].[Nd] QJVKUMXDEUEQLH-UHFFFAOYSA-N 0.000 title claims abstract description 26
- 239000000428 dust Substances 0.000 claims abstract description 111
- 238000004062 sedimentation Methods 0.000 claims abstract description 39
- 229910052761 rare earth metal Inorganic materials 0.000 claims abstract description 34
- 239000002918 waste heat Substances 0.000 claims abstract description 33
- 150000002910 rare earth metals Chemical class 0.000 claims abstract description 32
- 230000008569 process Effects 0.000 claims abstract description 31
- 238000001816 cooling Methods 0.000 claims abstract description 19
- 238000007254 oxidation reaction Methods 0.000 claims abstract description 15
- 230000003647 oxidation Effects 0.000 claims abstract description 11
- 239000002245 particle Substances 0.000 claims abstract description 11
- 238000002485 combustion reaction Methods 0.000 claims abstract description 10
- 230000002269 spontaneous effect Effects 0.000 claims abstract description 10
- 239000012528 membrane Substances 0.000 claims abstract description 8
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 claims description 43
- 239000003546 flue gas Substances 0.000 claims description 43
- 239000000779 smoke Substances 0.000 claims description 41
- XEEYBQQBJWHFJM-UHFFFAOYSA-N iron Substances [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims description 30
- 238000006243 chemical reaction Methods 0.000 claims description 10
- 229910052742 iron Inorganic materials 0.000 claims description 8
- 230000035939 shock Effects 0.000 claims description 8
- 239000004071 soot Substances 0.000 claims description 8
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 7
- 238000006477 desulfuration reaction Methods 0.000 claims description 7
- 230000023556 desulfurization Effects 0.000 claims description 7
- 230000005855 radiation Effects 0.000 claims description 7
- 229910001404 rare earth metal oxide Inorganic materials 0.000 claims description 7
- 239000003513 alkali Substances 0.000 claims description 5
- 229910052799 carbon Inorganic materials 0.000 claims description 5
- 238000001179 sorption measurement Methods 0.000 claims description 5
- 239000007921 spray Substances 0.000 claims description 4
- 229910000831 Steel Inorganic materials 0.000 claims description 3
- 238000010438 heat treatment Methods 0.000 claims description 3
- 239000010959 steel Substances 0.000 claims description 3
- 239000003245 coal Substances 0.000 claims 2
- 238000011084 recovery Methods 0.000 abstract description 2
- 239000007789 gas Substances 0.000 description 15
- MWUXSHHQAYIFBG-UHFFFAOYSA-N nitrogen oxide Inorganic materials O=[N] MWUXSHHQAYIFBG-UHFFFAOYSA-N 0.000 description 9
- RAHZWNYVWXNFOC-UHFFFAOYSA-N Sulphur dioxide Chemical compound O=S=O RAHZWNYVWXNFOC-UHFFFAOYSA-N 0.000 description 6
- 238000004519 manufacturing process Methods 0.000 description 6
- 239000000463 material Substances 0.000 description 6
- 230000000694 effects Effects 0.000 description 5
- 239000012855 volatile organic compound Substances 0.000 description 5
- 230000007547 defect Effects 0.000 description 4
- 238000005516 engineering process Methods 0.000 description 3
- 230000001590 oxidative effect Effects 0.000 description 3
- 238000004064 recycling Methods 0.000 description 3
- 238000005507 spraying Methods 0.000 description 3
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 2
- 229910002651 NO3 Inorganic materials 0.000 description 2
- NHNBFGGVMKEFGY-UHFFFAOYSA-N Nitrate Chemical compound [O-][N+]([O-])=O NHNBFGGVMKEFGY-UHFFFAOYSA-N 0.000 description 2
- 230000009471 action Effects 0.000 description 2
- 230000004075 alteration Effects 0.000 description 2
- 239000003054 catalyst Substances 0.000 description 2
- 238000004140 cleaning Methods 0.000 description 2
- 239000000446 fuel Substances 0.000 description 2
- 230000005484 gravity Effects 0.000 description 2
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 239000000843 powder Substances 0.000 description 2
- 238000012545 processing Methods 0.000 description 2
- 239000002994 raw material Substances 0.000 description 2
- 238000007670 refining Methods 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- 238000006467 substitution reaction Methods 0.000 description 2
- 238000012546 transfer Methods 0.000 description 2
- ZOXJGFHDIHLPTG-UHFFFAOYSA-N Boron Chemical compound [B] ZOXJGFHDIHLPTG-UHFFFAOYSA-N 0.000 description 1
- 229910052692 Dysprosium Inorganic materials 0.000 description 1
- 229910052688 Gadolinium Inorganic materials 0.000 description 1
- 229910052779 Neodymium Inorganic materials 0.000 description 1
- 229910052777 Praseodymium Inorganic materials 0.000 description 1
- 229910052771 Terbium Inorganic materials 0.000 description 1
- 239000002253 acid Substances 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 229910052796 boron Inorganic materials 0.000 description 1
- 229910002092 carbon dioxide Inorganic materials 0.000 description 1
- 239000001569 carbon dioxide Substances 0.000 description 1
- 239000000919 ceramic Substances 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000007599 discharging Methods 0.000 description 1
- KBQHZAAAGSGFKK-UHFFFAOYSA-N dysprosium atom Chemical compound [Dy] KBQHZAAAGSGFKK-UHFFFAOYSA-N 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- UIWYJDYFSGRHKR-UHFFFAOYSA-N gadolinium atom Chemical compound [Gd] UIWYJDYFSGRHKR-UHFFFAOYSA-N 0.000 description 1
- 238000002386 leaching Methods 0.000 description 1
- 239000000696 magnetic material Substances 0.000 description 1
- 238000005272 metallurgy Methods 0.000 description 1
- 239000003345 natural gas Substances 0.000 description 1
- QEFYFXOXNSNQGX-UHFFFAOYSA-N neodymium atom Chemical compound [Nd] QEFYFXOXNSNQGX-UHFFFAOYSA-N 0.000 description 1
- -1 particulate matters Substances 0.000 description 1
- 238000005498 polishing Methods 0.000 description 1
- PUDIUYLPXJFUGB-UHFFFAOYSA-N praseodymium atom Chemical compound [Pr] PUDIUYLPXJFUGB-UHFFFAOYSA-N 0.000 description 1
- 230000000630 rising effect Effects 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
- GZCRRIHWUXGPOV-UHFFFAOYSA-N terbium atom Chemical compound [Tb] GZCRRIHWUXGPOV-UHFFFAOYSA-N 0.000 description 1
- 238000011144 upstream manufacturing Methods 0.000 description 1
Classifications
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F27—FURNACES; KILNS; OVENS; RETORTS
- F27D—DETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS, OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
- F27D17/00—Arrangements for using waste heat; Arrangements for using, or disposing of, waste gases
- F27D17/004—Systems for reclaiming waste heat
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F22—STEAM GENERATION
- F22B—METHODS OF STEAM GENERATION; STEAM BOILERS
- F22B1/00—Methods of steam generation characterised by form of heating method
- F22B1/02—Methods of steam generation characterised by form of heating method by exploitation of the heat content of hot heat carriers
- F22B1/18—Methods of steam generation characterised by form of heating method by exploitation of the heat content of hot heat carriers the heat carrier being a hot gas, e.g. waste gas such as exhaust gas of internal-combustion engines
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F27—FURNACES; KILNS; OVENS; RETORTS
- F27D—DETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS, OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
- F27D17/00—Arrangements for using waste heat; Arrangements for using, or disposing of, waste gases
- F27D17/008—Arrangements for using waste heat; Arrangements for using, or disposing of, waste gases cleaning gases
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F27—FURNACES; KILNS; OVENS; RETORTS
- F27D—DETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS, OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
- F27D17/00—Arrangements for using waste heat; Arrangements for using, or disposing of, waste gases
- F27D17/004—Systems for reclaiming waste heat
- F27D2017/006—Systems for reclaiming waste heat using a boiler
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Environmental & Geological Engineering (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Life Sciences & Earth Sciences (AREA)
- Sustainable Development (AREA)
- Sustainable Energy (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Treating Waste Gases (AREA)
Abstract
The invention relates to the field of rare earth recovery, in particular to a method for purifying and treating neodymium iron boron waste roasting waste gas, which comprises the following steps of S1: spontaneous combustion oxidation roasting, S2: primary dust fall of waste heat boiler membrane wall, S3: secondary dust fall of the waste heat boiler evaporator, S4: and (3) carrying out dust fall on the waste heat boiler economizer for three times, wherein S5: and (5) bag dust removal. The front end of the waste heat boiler is provided with the film wall primary dust fall cooling sedimentation chamber for the first time, 90% of particles in the process waste gas are sedimentated and recycled to the process of dissolving and extracting rare earth, and precious rare earth resource loss is reduced.
Description
Technical Field
The invention relates to the field of rare earth recovery, in particular to a method for purifying and treating neodymium iron boron waste roasting waste gas.
Background
The upstream of the NdFeB waste is the manufacturing enterprise of NdFeB permanent magnet materials, and 30% of waste is generated in the production and use processes due to the production process and the use factors. The neodymium-iron-boron waste is basically consistent with the components of the neodymium-iron-boron magnetic material and consists of rare earth, iron and boron, wherein praseodymium and neodymium are about 87%, gadolinium is about 4%, dysprosium is about 3% and terbium is about 0.5%. With the rapid development of IT industry, automobiles and machinery manufacturing industry, there is an increasing market demand for neodymium-iron-boron magnets.
The downstream application of neodymium iron boron waste recycling is mainly distributed in the fields of permanent magnets, batteries, metallurgy, automobile catalysts, FCC catalysts, polishing powder, ceramics, fluorescent powder and the like, and the application is wide. The national exploitation of the rare earth raw ore realizes the ordered production plan management and the strict total rare earth exploitation amount management. Under the condition that the rare earth resource market is limited in supply, the secondary utilization of the rare earth resource is beneficial to saving resources, avoiding the waste of the rare earth resource, reducing industrial garbage and protecting the environment.
The neodymium iron boron waste is mainly derived from the leftover materials of rare earth deep processing enterprises, and raw materials in the whole industry are in short supply due to limited leftover materials. However, from overseas experience, developed countries generally establish a rare earth waste recycling system, and not only are the leftover materials of rare earth deep processing enterprises high in rare earth content, but also other waste products have high rare earth content, such as motor motors of electric bicycles, wherein each motor contains 300-500 g of rare earth permanent magnet materials. According to the data provided by the U.S. environmental protection agency, 25% of the consumer electronics products were recovered and used to extract rare earths, 38% from computer scrap, 18% from television scrap, 8% from mobile phone scrap, and 3% -5% from fluorescent lighting scrap, with these larger raw material sources being the most readily available sources of recoverable rare earths. Therefore, with the expansion of the production scale of the downstream neodymium iron boron permanent magnet material in the future, the supply amount of neodymium iron boron waste will increase, and thus the market scale of the industry will also further increase. However, a large amount of process waste gas (including smoke dust, nitrogen oxides, sulfur dioxide, VOCs and the like) can be generated in the process of oxidizing roasting neodymium iron boron waste materials of neodymium iron boron waste material recycling enterprises, and if the process waste gas is not effectively treated, the damage such as the loss of rare earth in the smoke dust and the pollution of the process waste gas to the atmosphere can be caused.
The invention is researched and proposed for overcoming the defects of the prior art.
Disclosure of Invention
The invention aims to overcome the defects of the prior art and provides a method for purifying and treating neodymium iron boron waste roasting waste gas.
The invention can be realized by the following technical scheme:
the invention discloses a method for purifying and treating neodymium iron boron waste roasting waste gas, which comprises the following steps:
s1: spontaneous combustion oxidation roasting, namely heating and roasting neodymium iron boron waste, wherein the roasting temperature is controlled to be 600-900 ℃, the roasting time is 2-3 hours, and meanwhile, process waste gas is generated, and Fe and rare earth metals in the waste are oxidized into Fe 2 O 3 And rare earth oxide, the oxidation rate of iron and rare earth metal reaches 95% -99%, and the reaction temperature is controlled according to the feeding speed;
s2: the membrane wall of the waste heat boiler carries out primary dust fall, the process waste gas enters the waste heat boiler, the cavity structure of the membrane wall cooling sedimentation chamber is utilized for carrying out primary sedimentation, the smoke after primary sedimentation is obtained, the flow velocity of the process waste gas is controlled to be 1.2-1.5m/s, and the primary dust fall rate reaches more than 90%;
s3: the method comprises the steps that secondary dust fall is carried out on a waste heat boiler evaporator, smoke after primary sedimentation enters a boiler radiation cooling chamber from the bottom of a boiler front wall, the average flow speed is 1.2-1.5m/s, then enters an evaporator flue section at the 90-degree turning level at the top of the boiler, secondary dust fall smoke is obtained after the smoke exits the evaporator, the average smoke flow speed in the evaporator is 4.5-5.0m/s, two ash hoppers are arranged at the lower part of the evaporator, a smoke baffle is arranged in each ash hopper, and a shock wave soot blower is arranged at the same time, so that the secondary dust fall rate is more than 96%;
s4: the waste heat boiler economizer is subjected to three times of dust fall, the flue gas enters the economizer downwards after secondary sedimentation for three times of sedimentation, and the particulate matters in the flue gas are removed by more than 98% after the three times of dust fall;
s5: the flue gas after three times of sedimentation enters a bag-type dust remover, wherein the bag-type dust remover is a film-covered pulse full-offline bag-type dust remover, and the removal rate of particles in the flue gas after bag-type dust removal is over 99.9 percent;
s6: and (3) carrying out alkali spray desulfurization and denitration treatment on the flue gas after bag dust removal, and then carrying out wet electric dust removal and active carbon adsorption treatment to finally achieve the emission reaching the standard.
S1: spontaneous combustion oxidation roasting is carried out, oil is contained on the surface of neodymium iron boron waste, and Fe oxidation reaction is exothermic reaction, so that no fuel is needed, heat sources in a kiln are used for generating heat of oxidation reaction of iron, rare earth elements and blown air, spontaneous combustion of rare earth metal simple substances occurs when the temperature reaches more than 280 ℃, in order to improve the rare earth leaching rate of an acid dissolving process, the neodymium iron boron waste is firstly heated and roasted, the roasting temperature is controlled to 600-900 ℃, the roasting time is 2-3 hours, and Fe and rare earth metals in the waste are oxidized into Fe 2 O 3 And rare earth oxide, the oxidation rate of iron and rare earth metal reaches 95% -99%, the reaction temperature is controlled according to the feeding speed, VOCs, particulate matters, nitrogen oxides and sulfur dioxide process waste gas are produced in the spontaneous combustion roasting process, wherein the particulate matters are Fe 2 O 3 And rare earth oxides;
s2: the film wall of the waste heat boiler carries out primary dust fall, process waste gas generated by oxidizing roasting of neodymium iron boron waste enters the waste heat boiler, the cavity structure of the film wall cooling sedimentation chamber is utilized for carrying out primary sedimentation, the flow speed of the process waste gas is controlled to be 1.2-1.5m/s, the sedimentation of smoke dust under the cooling effect is facilitated, and the primary dust fall rate is more than 90%;
s3: the secondary dust fall of the waste heat boiler evaporator, the smoke enters the radiation cooling chamber of the boiler from the bottom of the front wall of the boiler after primary sedimentation, the average smoke flow rate is 1.2-1.5m/s, the dust-containing smoke slowly moves downwards in the radiation cooling chamber, part of the dust is separated out under the action of gravity and falls into the dust bin at the lower part of the boiler, then enters the flue section of the evaporator at the 90-degree turning level at the top of the boiler, the smoke after secondary sedimentation is obtained after the smoke exits the evaporator, the average smoke flow rate in the evaporator is 4.5-5.0m/s, two dust hoppers are arranged at the lower part of the evaporator, and smoke baffles are arranged in the dust hoppers to avoid short circuit of the smoke in the dust hoppers. Meanwhile, a shock wave soot blower is arranged to remove dust on the tube bundle, so that the high-efficiency heat exchange between the flue gas and the tube bundle is ensured, and the secondary dust fall rate is up to more than 96%;
s4: and the flue gas enters the economizer downwards after secondary sedimentation for three times of dust fall, and the flow speed of the flue gas is controlled in the whole flue gas flow path so that the self-ash-cleaning effect can be effectively exerted. The special structure of the waste heat boiler is utilized, so that the particulate matters in the smoke dust are removed by more than 98% after the dust is reduced for three times by the waste heat boiler;
s5: the method comprises the steps that smoke enters a bag-type dust remover after three times of sedimentation, the bag-type dust remover is a film-covered pulse full-off-line bag-type dust remover, the adopted film-covered pulse full-off-line bag-type dust remover consists of an ash bucket, an upper box body, a middle box body and a lower box body, the upper box body, the middle box body and the lower box body are of a chamber-separating structure, dust-containing gas enters the ash bucket through an air inlet duct during operation, coarse dust particles directly fall into the bottom of the ash bucket, fine dust particles upwards enter the middle box body and the lower box body along with turning of air flow, dust is accumulated on the outer surface of a filter bag, filtered gas enters the upper box body to a clean air collecting pipe and is discharged to a desulfurization nitrate spraying device, the pulse bag-type dust remover adopts a chamber-separating air-stopping pulse jetting ash removing technology, the defects of a conventional pulse dust remover and a chamber-separating blowback dust remover are overcome, the ash removing capability is strong, the dust removing efficiency is high, the emission concentration is low, the air leakage rate is small, the occupied area is small, the operation is stable and reliable, and the dust removing rate reaches 99.9%;
s6: and (3) carrying out alkali spray desulfurization and denitration treatment on the flue gas after bag dust removal, carrying out refining treatment through a wet electric dust removal device, and removing VOCs through an activated carbon adsorption process to finally achieve the emission reaching the standard.
The utility model provides a waste heat boiler, contain the exhaust-gas pipeline of vertical setting, the annular is provided with the diaphragm type wall that comprises seamless steel pipe and heat transfer fin that is used for removing reaction heat in the exhaust-gas pipeline, exhaust-gas pipeline forms diaphragm type wall cooling sedimentation chamber with the diaphragm type wall, exhaust-gas pipeline bottom one side is provided with the flue gas entry, exhaust-gas pipeline top one side has the evaporimeter through the pipe connection, the evaporimeter bottom is provided with two ash hoppers, and still be provided with the shock wave soot blower on the evaporimeter, evaporimeter one side still is provided with the economizer through the pipe connection, still be provided with the flue gas export on the pipeline of economizer bottom.
Compared with the prior art, the invention has the following advantages:
1. the front end of the waste heat boiler is provided with the film wall primary dust fall cooling sedimentation chamber for the first time, 90% of particles in the process waste gas are sedimentated and recycled to the process of dissolving and extracting rare earth, and precious rare earth resource loss is reduced.
2. The waste gas of the process reaches a better flue gas separation effect after passing through the membrane wall for one-time dust fall, so that cleaner high-temperature flue gas is convenient to enter the evaporator of the waste heat boiler, the scaling of the flue pipe is prevented, the heat efficiency of the boiler is improved, and the waste heat boiler is more economical, more energy-saving and more environment-friendly.
3. The traditional cyclone dust fall, long-pipeline dust fall and surface cooler dust fall process routes are replaced by adopting the primary dust fall of the waste heat boiler film wall settling chamber, the secondary dust fall of the evaporator and the tertiary dust fall of the economizer. The method fully and efficiently utilizes the heat of the flue gas to produce steam, can reduce the consumption of natural gas and the emission of carbon dioxide, and has remarkable practical significance for realizing the carbon-to-carbon emission target.
Drawings
The invention is described in further detail below with reference to the attached drawing figures, wherein:
FIG. 1 is a junction process flow diagram of the present invention;
FIG. 2 is a schematic structural view of a waste heat boiler;
in the figure: 1. a flue gas inlet; 2. a smoke exhaust duct; 3. an evaporator; 4. an ash bucket; 5. a pipe; 6. an economizer; 7. a flue gas outlet;
Detailed Description
Embodiments of the present invention will be described in detail below with reference to the attached drawings:
examples
The invention discloses a method for purifying and treating neodymium iron boron waste roasting waste gas, which comprises the following steps:
s1: spontaneous combustion oxidation roasting, namely heating and roasting neodymium iron boron waste, wherein the roasting temperature is controlled to be 600-900 ℃, the roasting time is 2-3 hours, and meanwhile, process waste gas is generated, and Fe and rare earth metals in the waste are oxidized into Fe 2 O 3 And rare earth oxide, the oxidation rate of iron and rare earth metal reaches 95% -99%, and the reaction temperature is controlled according to the feeding speed;
s2: the membrane wall of the waste heat boiler carries out primary dust fall, the process waste gas enters the waste heat boiler, the cavity structure of the membrane wall cooling sedimentation chamber is utilized for carrying out primary sedimentation, the smoke after primary sedimentation is obtained, the flow velocity of the process waste gas is controlled to be 1.2-1.5m/s, and the primary dust fall rate reaches more than 90%;
s3: the method comprises the steps that secondary dust fall is carried out on a waste heat boiler evaporator, smoke after primary sedimentation enters a boiler radiation cooling chamber from the bottom of a boiler front wall, the average flow speed is 1.2-1.5m/s, then enters an evaporator flue section at the 90-degree turning level at the top of the boiler, secondary dust fall smoke is obtained after the smoke exits the evaporator, the average smoke flow speed in the evaporator is 4.5-5.0m/s, two ash hoppers are arranged at the lower part of the evaporator, a smoke baffle is arranged in each ash hopper, and a shock wave soot blower is arranged at the same time, so that the secondary dust fall rate is more than 96%;
s4: the waste heat boiler economizer is subjected to three times of dust fall, the flue gas enters the economizer downwards after secondary sedimentation for three times of sedimentation, and the particulate matters in the flue gas are removed by more than 98% after the three times of dust fall;
s5: the flue gas after three times of sedimentation enters a bag-type dust remover, wherein the bag-type dust remover is a film-covered pulse full-offline bag-type dust remover, and the removal rate of particles in the flue gas after bag-type dust removal is over 99.9 percent;
s6: and (3) carrying out alkali spray desulfurization and denitration treatment on the flue gas after bag dust removal, and then carrying out wet electric dust removal and active carbon adsorption treatment to finally achieve the emission reaching the standard.
The embodiment specifically comprises the following steps:
s1: spontaneous combustion oxidation roasting is carried out, oil is contained on the surface of neodymium iron boron waste, and Fe oxidation reaction is exothermic reaction, so that no fuel is needed, heat sources in a kiln are from heat release of oxidation reaction of iron, rare earth elements and blown air, spontaneous combustion of rare earth metal simple substance occurs when the temperature reaches more than 280 ℃, temperature rising roasting of neodymium iron boron waste is needed firstly, roasting temperature is controlled to 800 ℃, roasting time is 2.5h, and Fe and rare earth metal in waste are oxidized into Fe 2 O 3 And rare earth oxide, the oxidation rate of iron and rare earth metal reaches 98%, the reaction temperature is controlled according to the feeding speed, and VOC can be generated in the spontaneous combustion roasting processs, particles, nitrogen oxides and sulfur dioxide waste gas, wherein the particles are Fe 2 O 3 And rare earth oxides;
s2: the film wall of the waste heat boiler carries out primary dust fall, process waste gas generated by oxidizing roasting of neodymium iron boron waste enters the waste heat boiler, the cavity structure of the film wall cooling sedimentation chamber is utilized for carrying out primary sedimentation, the flow speed of the process waste gas is controlled to be 1.4m/s, the sedimentation of smoke dust under the cooling effect is facilitated, and the primary dust fall rate reaches 92%;
s3: the secondary dust fall of the waste heat boiler evaporator, the flue gas enters the boiler radiation cooling chamber at the bottom of the front wall of the boiler after primary sedimentation, the average flue gas flow rate is 1.4m/s, so that the dust-containing flue gas slowly moves downwards in the radiation cooling chamber, part of the flue gas is separated out under the action of gravity and falls into the ash bin at the lower part of the boiler, then enters the flue section of the evaporator at the 90-degree turning level at the top of the boiler, the average flue gas flow rate of the flue gas in the evaporator is 4.8m/s, two ash hoppers are arranged at the lower part of the evaporator, and in order to avoid short circuit of the flue gas in the ash hoppers, flue gas baffles are arranged in the ash hoppers. Meanwhile, a shock wave soot blower is arranged to remove dust on the tube bundle, so that the high-efficiency heat exchange between the flue gas and the tube bundle is ensured, and the secondary dust fall rate reaches 97%;
s4: and the flue gas enters the economizer downwards after secondary sedimentation for three times of dust fall, and the self-ash-cleaning effect can be effectively exerted by controlling the flow rate of the flue gas in the whole flue gas flow. The special structure of the waste heat boiler is utilized, so that the particulate matters in the smoke dust are removed by 99% after the dust is reduced for three times by the waste heat boiler;
s5: the flue gas enters a bag-type dust remover after three times of sedimentation, the bag-type dust remover is a film-covered pulse full-offline bag-type dust remover, the film-covered pulse full-offline bag-type dust remover consists of an ash bucket, an upper box body, a middle box body and a lower box body, the upper box body, the middle box body and the lower box body are of a sub-chamber structure, when the dust-free pulse full-offline bag-type dust remover works, dust-containing gas enters the ash bucket through an air inlet duct, coarse dust particles directly fall into the bottom of the ash bucket, fine dust particles upwards enter the middle box body and the lower box body along with turning of air flow, dust is accumulated on the outer surface of a filter bag, filtered gas enters the upper box body to a clean gas collecting pipe and is discharged to a desulfurization nitrate spraying device, the pulse bag-type dust remover adopts a sub-chamber air-stopping pulse jetting dust removing technology, the defects of a conventional pulse dust remover and the sub-chamber blowback dust remover are overcome, the dust removing capability is strong, the dust removing efficiency is high, the discharging concentration is low, the air leakage rate is small, the occupied area is small, the operation is stable and reliable, and the dust removing rate reaches 99.9%;
s6: after desulfurization and denitration treatment is carried out by adopting a mature and reliable alkali spraying technology, the wet electric dust collector is used for refining treatment, and VOCs are removed by an activated carbon adsorption process, so that the emission reaching the standard is finally achieved.
The utility model provides an exhaust-heat boiler, contain the exhaust-gas pipeline 2 of vertical setting, the annular is provided with the diaphragm type wall that is used for removing reaction heat by seamless steel pipe and heat transfer fin constitution in the exhaust-gas pipeline 2, exhaust-gas pipeline 2 forms diaphragm type wall cooling sedimentation chamber with the diaphragm type wall, exhaust-gas pipeline 2 bottom one side is provided with flue gas entry 1, exhaust-gas pipeline 2 top one side is connected with evaporimeter 3 through the pipe connection, evaporimeter 3 bottom is provided with two ash hoppers 4, and still be provided with shock wave soot blower on the evaporimeter 3, evaporimeter one side is still connected with economizer 6 through pipe 5, still be provided with flue gas outlet 7 on the pipeline of economizer 6 bottom, pass through the pipe connection sack cleaner on the flue gas outlet 7.
The foregoing is merely a preferred embodiment of the present invention, and it should be noted that various changes, modifications, substitutions and alterations can be made herein by those skilled in the art without departing from the technical principles of the present invention, and such changes, modifications, substitutions and alterations are also to be regarded as the scope of the invention.
Claims (2)
1. The method for purifying and treating the neodymium iron boron waste roasting waste gas is characterized by comprising the following steps of:
s1: spontaneous combustion oxidation roasting, namely heating and roasting neodymium iron boron waste, wherein the roasting temperature is controlled to be 600-900 ℃, the roasting time is 2-3 hours, and meanwhile, process waste gas is generated, and Fe and rare earth metals in the waste are oxidized into Fe 2 O 3 And rare earth oxide, the oxidation rate of iron and rare earth metal reaches 95% -99%, and the reaction temperature is controlled according to the feeding speed;
s2: the membrane wall of the waste heat boiler carries out primary dust fall, the process waste gas enters the waste heat boiler, the cavity structure of the membrane wall cooling sedimentation chamber is utilized for carrying out primary sedimentation, the smoke after primary sedimentation is obtained, the flow velocity of the process waste gas is controlled to be 1.2-1.5m/s, and the primary dust fall rate reaches more than 90%;
s3: the method comprises the steps that secondary dust fall is carried out on a waste heat boiler evaporator, smoke after primary sedimentation enters a boiler radiation cooling chamber from the bottom of a boiler front wall, the average flow speed is 1.2-1.5m/s, then enters an evaporator flue section at the 90-degree turning level at the top of the boiler, secondary dust fall smoke is obtained after the smoke exits the evaporator, the average smoke flow speed in the evaporator is 4.5-5.0m/s, two ash hoppers are arranged at the lower part of the evaporator, a smoke baffle is arranged in each ash hopper, and a shock wave soot blower is arranged at the same time, so that the secondary dust fall rate is more than 96%;
s4: the waste heat boiler economizer is subjected to three times of dust fall, the flue gas enters the economizer downwards after secondary sedimentation for three times of sedimentation, and the particulate matters in the flue gas are removed by more than 98% after the three times of dust fall;
s5: the flue gas after three times of sedimentation enters a bag-type dust remover, wherein the bag-type dust remover is a film-covered pulse full-offline bag-type dust remover, and the removal rate of particles in the flue gas after bag-type dust removal is over 99.9 percent;
s6: and (3) carrying out alkali spray desulfurization and denitration treatment on the flue gas after bag dust removal, and then carrying out wet electric dust removal and active carbon adsorption treatment to finally achieve the emission reaching the standard.
2. A waste heat boiler, characterized in that: the device comprises a vertically arranged smoke exhaust pipeline, wherein a film wall which is used for removing reaction heat and consists of a seamless steel pipe and heat exchange fins is annularly arranged in the smoke exhaust pipeline, a film wall cooling sedimentation chamber is formed by the smoke exhaust pipeline and the film wall, a smoke inlet is formed in one side of the bottom of the smoke exhaust pipeline, an evaporator is connected to one side of the top of the smoke exhaust pipeline through a pipeline, two ash hoppers are arranged at the bottom of the evaporator, a shock wave soot blower is further arranged on the evaporator, a coal economizer is further connected to one side of the evaporator through a pipeline, and a smoke outlet is further arranged on the pipeline at the bottom of the coal economizer.
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Application publication date: 20231222 |