CN114715916B - Process and equipment for recycling nitrogen trifluoride electrolysis residues - Google Patents
Process and equipment for recycling nitrogen trifluoride electrolysis residues Download PDFInfo
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- CN114715916B CN114715916B CN202210141236.1A CN202210141236A CN114715916B CN 114715916 B CN114715916 B CN 114715916B CN 202210141236 A CN202210141236 A CN 202210141236A CN 114715916 B CN114715916 B CN 114715916B
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- 238000000034 method Methods 0.000 title claims abstract description 42
- QKCGXXHCELUCKW-UHFFFAOYSA-N n-[4-[4-(dinaphthalen-2-ylamino)phenyl]phenyl]-n-naphthalen-2-ylnaphthalen-2-amine Chemical compound C1=CC=CC2=CC(N(C=3C=CC(=CC=3)C=3C=CC(=CC=3)N(C=3C=C4C=CC=CC4=CC=3)C=3C=C4C=CC=CC4=CC=3)C3=CC4=CC=CC=C4C=C3)=CC=C21 QKCGXXHCELUCKW-UHFFFAOYSA-N 0.000 title claims abstract description 38
- 238000004064 recycling Methods 0.000 title claims abstract description 31
- 238000005868 electrolysis reaction Methods 0.000 title claims description 13
- 239000007789 gas Substances 0.000 claims abstract description 53
- 238000000197 pyrolysis Methods 0.000 claims abstract description 48
- 239000000843 powder Substances 0.000 claims abstract description 43
- MIMUSZHMZBJBPO-UHFFFAOYSA-N 6-methoxy-8-nitroquinoline Chemical compound N1=CC=CC2=CC(OC)=CC([N+]([O-])=O)=C21 MIMUSZHMZBJBPO-UHFFFAOYSA-N 0.000 claims abstract description 37
- 229910044991 metal oxide Inorganic materials 0.000 claims abstract description 25
- 150000004706 metal oxides Chemical class 0.000 claims abstract description 25
- 229910001512 metal fluoride Inorganic materials 0.000 claims abstract description 23
- BRPQOXSCLDDYGP-UHFFFAOYSA-N calcium oxide Chemical compound [O-2].[Ca+2] BRPQOXSCLDDYGP-UHFFFAOYSA-N 0.000 claims abstract description 19
- ODINCKMPIJJUCX-UHFFFAOYSA-N calcium oxide Inorganic materials [Ca]=O ODINCKMPIJJUCX-UHFFFAOYSA-N 0.000 claims abstract description 19
- 239000000292 calcium oxide Substances 0.000 claims abstract description 19
- VHUUQVKOLVNVRT-UHFFFAOYSA-N Ammonium hydroxide Chemical compound [NH4+].[OH-] VHUUQVKOLVNVRT-UHFFFAOYSA-N 0.000 claims abstract description 17
- 235000011114 ammonium hydroxide Nutrition 0.000 claims abstract description 17
- 239000007787 solid Substances 0.000 claims abstract description 14
- WUKWITHWXAAZEY-UHFFFAOYSA-L calcium difluoride Chemical compound [F-].[F-].[Ca+2] WUKWITHWXAAZEY-UHFFFAOYSA-L 0.000 claims abstract description 9
- 229910001634 calcium fluoride Inorganic materials 0.000 claims abstract description 9
- 238000001816 cooling Methods 0.000 claims description 45
- 238000006115 defluorination reaction Methods 0.000 claims description 36
- 239000000463 material Substances 0.000 claims description 25
- 238000002425 crystallisation Methods 0.000 claims description 18
- 230000008025 crystallization Effects 0.000 claims description 18
- 238000011282 treatment Methods 0.000 claims description 16
- YCKRFDGAMUMZLT-UHFFFAOYSA-N Fluorine atom Chemical compound [F] YCKRFDGAMUMZLT-UHFFFAOYSA-N 0.000 claims description 15
- 239000011737 fluorine Substances 0.000 claims description 15
- 229910052731 fluorine Inorganic materials 0.000 claims description 15
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 claims description 14
- 238000007599 discharging Methods 0.000 claims description 14
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 13
- 239000008399 tap water Substances 0.000 claims description 10
- 235000020679 tap water Nutrition 0.000 claims description 10
- 238000009833 condensation Methods 0.000 claims description 9
- 230000005494 condensation Effects 0.000 claims description 9
- GVGCUCJTUSOZKP-UHFFFAOYSA-N nitrogen trifluoride Chemical group FN(F)F GVGCUCJTUSOZKP-UHFFFAOYSA-N 0.000 claims description 9
- 238000011084 recovery Methods 0.000 claims description 8
- 229910021529 ammonia Inorganic materials 0.000 claims description 7
- 238000010438 heat treatment Methods 0.000 claims description 7
- 238000003860 storage Methods 0.000 claims description 7
- 239000000498 cooling water Substances 0.000 claims description 5
- 238000005485 electric heating Methods 0.000 claims description 4
- 150000003839 salts Chemical class 0.000 claims description 4
- 238000010521 absorption reaction Methods 0.000 claims description 2
- 238000010298 pulverizing process Methods 0.000 claims 1
- KRHYYFGTRYWZRS-UHFFFAOYSA-N Fluorane Chemical compound F KRHYYFGTRYWZRS-UHFFFAOYSA-N 0.000 abstract description 39
- 229910000040 hydrogen fluoride Inorganic materials 0.000 abstract description 34
- 239000007788 liquid Substances 0.000 abstract description 6
- 238000004519 manufacturing process Methods 0.000 abstract description 4
- 238000000926 separation method Methods 0.000 abstract description 3
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 16
- 239000002699 waste material Substances 0.000 description 13
- 229910000480 nickel oxide Inorganic materials 0.000 description 11
- GNRSAWUEBMWBQH-UHFFFAOYSA-N oxonickel Chemical compound [Ni]=O GNRSAWUEBMWBQH-UHFFFAOYSA-N 0.000 description 11
- 229910052759 nickel Inorganic materials 0.000 description 8
- XKMRRTOUMJRJIA-UHFFFAOYSA-N ammonia nh3 Chemical compound N.N XKMRRTOUMJRJIA-UHFFFAOYSA-N 0.000 description 7
- 238000005265 energy consumption Methods 0.000 description 5
- 239000002893 slag Substances 0.000 description 5
- UQSXHKLRYXJYBZ-UHFFFAOYSA-N Iron oxide Chemical compound [Fe]=O UQSXHKLRYXJYBZ-UHFFFAOYSA-N 0.000 description 4
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 4
- 238000009835 boiling Methods 0.000 description 4
- 239000012535 impurity Substances 0.000 description 4
- 239000000126 substance Substances 0.000 description 4
- 238000005336 cracking Methods 0.000 description 3
- 239000003344 environmental pollutant Substances 0.000 description 3
- 229910052751 metal Inorganic materials 0.000 description 3
- 239000002184 metal Substances 0.000 description 3
- DBJLJFTWODWSOF-UHFFFAOYSA-L nickel(ii) fluoride Chemical compound F[Ni]F DBJLJFTWODWSOF-UHFFFAOYSA-L 0.000 description 3
- 239000002245 particle Substances 0.000 description 3
- 231100000719 pollutant Toxicity 0.000 description 3
- 238000007789 sealing Methods 0.000 description 3
- DDFHBQSCUXNBSA-UHFFFAOYSA-N 5-(5-carboxythiophen-2-yl)thiophene-2-carboxylic acid Chemical compound S1C(C(=O)O)=CC=C1C1=CC=C(C(O)=O)S1 DDFHBQSCUXNBSA-UHFFFAOYSA-N 0.000 description 2
- QPLDLSVMHZLSFG-UHFFFAOYSA-N Copper oxide Chemical compound [Cu]=O QPLDLSVMHZLSFG-UHFFFAOYSA-N 0.000 description 2
- 239000005751 Copper oxide Substances 0.000 description 2
- 239000003513 alkali Substances 0.000 description 2
- 238000004140 cleaning Methods 0.000 description 2
- 229910000431 copper oxide Inorganic materials 0.000 description 2
- 238000001704 evaporation Methods 0.000 description 2
- 230000008020 evaporation Effects 0.000 description 2
- -1 fluoride ions Chemical class 0.000 description 2
- 229910001385 heavy metal Inorganic materials 0.000 description 2
- 239000007791 liquid phase Substances 0.000 description 2
- 238000002844 melting Methods 0.000 description 2
- 230000008018 melting Effects 0.000 description 2
- 238000000746 purification Methods 0.000 description 2
- 239000002351 wastewater Substances 0.000 description 2
- 235000008733 Citrus aurantifolia Nutrition 0.000 description 1
- 229910021594 Copper(II) fluoride Inorganic materials 0.000 description 1
- KRHYYFGTRYWZRS-UHFFFAOYSA-M Fluoride anion Chemical compound [F-] KRHYYFGTRYWZRS-UHFFFAOYSA-M 0.000 description 1
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 1
- 235000011941 Tilia x europaea Nutrition 0.000 description 1
- OUUPFKRCJACIIT-UHFFFAOYSA-N [O].[Ni].[Ni]=O Chemical compound [O].[Ni].[Ni]=O OUUPFKRCJACIIT-UHFFFAOYSA-N 0.000 description 1
- 239000007864 aqueous solution Substances 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 239000000356 contaminant Substances 0.000 description 1
- GWFAVIIMQDUCRA-UHFFFAOYSA-L copper(ii) fluoride Chemical compound [F-].[F-].[Cu+2] GWFAVIIMQDUCRA-UHFFFAOYSA-L 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 239000003792 electrolyte Substances 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000005530 etching Methods 0.000 description 1
- 239000002920 hazardous waste Substances 0.000 description 1
- SHXXPRJOPFJRHA-UHFFFAOYSA-K iron(iii) fluoride Chemical compound F[Fe](F)F SHXXPRJOPFJRHA-UHFFFAOYSA-K 0.000 description 1
- 239000004571 lime Substances 0.000 description 1
- 238000004377 microelectronic Methods 0.000 description 1
- 150000007522 mineralic acids Chemical class 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 238000006386 neutralization reaction Methods 0.000 description 1
- 229910000510 noble metal Inorganic materials 0.000 description 1
- 238000005457 optimization Methods 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 238000001020 plasma etching Methods 0.000 description 1
- 238000001556 precipitation Methods 0.000 description 1
- 239000013049 sediment Substances 0.000 description 1
- 229910052710 silicon Inorganic materials 0.000 description 1
- 239000010703 silicon Substances 0.000 description 1
- 229910052814 silicon oxide Inorganic materials 0.000 description 1
- 238000009270 solid waste treatment Methods 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- 230000001988 toxicity Effects 0.000 description 1
- 231100000419 toxicity Toxicity 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01C—AMMONIA; CYANOGEN; COMPOUNDS THEREOF
- C01C1/00—Ammonia; Compounds thereof
- C01C1/16—Halides of ammonium
- C01C1/162—Ammonium fluoride
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01F—COMPOUNDS OF THE METALS BERYLLIUM, MAGNESIUM, ALUMINIUM, CALCIUM, STRONTIUM, BARIUM, RADIUM, THORIUM, OR OF THE RARE-EARTH METALS
- C01F11/00—Compounds of calcium, strontium, or barium
- C01F11/20—Halides
- C01F11/22—Fluorides
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
- C01G53/00—Compounds of nickel
- C01G53/04—Oxides; Hydroxides
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- C01P2006/00—Physical properties of inorganic compounds
- C01P2006/80—Compositional purity
-
- 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
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P10/00—Technologies related to metal processing
- Y02P10/20—Recycling
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Inorganic Chemistry (AREA)
- Life Sciences & Earth Sciences (AREA)
- Geology (AREA)
- Electrolytic Production Of Non-Metals, Compounds, Apparatuses Therefor (AREA)
- Processing Of Solid Wastes (AREA)
Abstract
The invention discloses a process and equipment for recycling resources of electrolytic residues of nitrogen trifluoride, wherein the process comprises the steps of firstly crushing the electrolytic residues, then carrying out high-temperature anaerobic pyrolysis, reserving metal fluoride in a powdery form, changing most of ammonium bifluoride and hydrogen fluoride into steam, introducing the steam after pyrolysis into a condensing device, condensing condensate liquid into ammonium bifluoride, crystallizing the condensate liquid into hydrogen fluoride, and recycling to obtain ammonium bifluoride solid; introducing the non-condensable hydrogen fluoride gas into a container filled with calcium oxide to react to generate calcium fluoride; the metal fluoride residues after pyrolysis are completely defluorinated by high-temperature steam, the defluorinated steam is absorbed by ammonia water, and the defluorinated metal oxide powder is cooled and then recovered. The invention utilizes the phase change characteristics of the gas, solid and liquid of ammonium bifluoride, hydrogen fluoride and metal fluoride at different temperatures, and realizes the separation and clean production of ammonium bifluoride, hydrogen fluoride and metal oxide in the electrolytic residue of nitrogen trifluoride and the recycling of resources by combining with equipment.
Description
Technical Field
The invention relates to the technical field of recovery of electrolytic residues of nitrogen trifluoride, in particular to a process and equipment for recovering resources of electrolytic residues of nitrogen trifluoride.
Background
The high-purity nitrogen trifluoride gas is used as an excellent plasma etching gas in the microelectronics industry, has excellent etching rate and selectivity to silicon and silicon oxide, and therefore plays an important role in various industries such as integrated circuits, chip manufacturing and the like. In industry, the production modes of nitrogen trifluoride include the following two modes: firstly, generating fluorine gas by electrolyzing anhydrous hydrogen fluoride, and then reacting with molten ammonium bifluoride to generate nitrogen trifluoride; and secondly, the mixture of anhydrous hydrogen fluoride and molten ammonium bifluoride is electrolyzed, so that nitrogen trifluoride can be directly generated in an electrolytic tank. The crude nitrogen trifluoride product obtained by the two processes has a large amount of hydrogen fluoride which needs to be removed in the subsequent purification process, but the existing purification technology adopts solid alkali or alkali liquor for absorption, the subsequent treatment process is complex, and secondary pollution is easy to cause. Therefore, further exploration and optimization of the process plant is necessary. In addition, hydrogen fluoride and ammonium fluoride belong to solid hazardous waste, and solid waste treatment is needed, otherwise serious waste of substances and heavy metal pollution can be caused.
In the process of preparing nitrogen trifluoride by an electrolytic method, nickel is gradually dissolved as an anode, and is deposited at the bottom of an electrolytic tank in the form of nickel fluoride, complex and the like, so that the electrolytic efficiency is affected. Therefore, the deposits in the electrolytic cell must be cleaned periodically to maintain the electrolysis in progress. The sediment which is cleaned is the electrolytic waste residue, and the content of ammonium bifluoride and hydrogen fluoride in the electrolytic waste residue is about 50-60% in practice; the rest solid consists of 55-65% of nickel fluoride, 25-35% of ferric fluoride, 8-12% of copper fluoride and 2% of impurities. Thorough cleaning is needed in the process of disassembling the electrolytic cell, and a large amount of wastewater containing fluorine and ammonia nitrogen is generated. Nickel is used as noble metal, has higher economic value, and can cause waste and serious heavy metal pollution if not recovered; the electrolytic waste residue contains a large amount of ammonium bifluoride, and is characterized in that pollutants are fluorine and ammonia nitrogen, the fluorine has strong toxicity, the ammonia nitrogen is also a serious pollutant, the fluorine and the ammonia nitrogen are second-class pollutants, the maximum allowable emission concentration of the fluoride is 6mg/L, and the ammonia nitrogen is 10mg/L.
At present, fluorine and ammonia nitrogen in electrolytic waste residues of nitrogen trifluoride and cleaning wastewater of an electrolytic tank are generally treated respectively. The method for treating the electrolytic waste residues of nitrogen trifluoride mainly comprises the following steps: the method comprises the steps of carrying out lime neutralization precipitation on fluoride ions in nickel-containing waste residues, and carrying out ammonia nitrogen treatment on ammonium ions by a chemical method, wherein the treatment mode is only innocent treatment, so that the recycling of resources is not realized, the waste of the resources is caused, and the treatment cost is increased; the other is to dissolve the electrolytic nickel-containing waste slag with water and then separate the solid from the liquid to form ammonium fluoride aqueous solution, the solid becomes nickel-containing waste slag, the solid slag needs to be separated continuously, the treatment mode is complex, and the separated nickel-containing waste slag belongs to dangerous waste and still needs to be treated by professional companies. And the method is characterized in that after the nickel slag is dissolved by hydrofluoric acid, sulfuric acid is added into the electrolyte, and metal nickel is recovered by electrolysis, so that the treatment mode consumes more energy, and after the sulfuric acid is added, other impurities are introduced, so that the subsequent treatment process and the cost are increased.
Disclosure of Invention
In order to overcome the defects of the prior art, one of the purposes of the invention is to provide a process for recycling resources of electrolytic residues of nitrogen trifluoride, which is characterized in that according to the gas-solid-liquid phase characteristics of hydrogen fluoride and ammonium bifluoride, the ammonium bifluoride and the hydrogen fluoride are evaporated from the electrolytic residues of nitrogen trifluoride by controlling proper temperature, and recycling of the resources is realized by condensation and crystallization; the second object of the invention is to provide a process equipment for recovering the resources of the electrolytic residues of nitrogen trifluoride, which separates ammonium bifluoride and hydrogen fluoride through a high-temperature anaerobic pyrolysis device, recovers ammonium bifluoride through condensation crystallization, recovers hydrogen fluoride through a calcium oxide tank, defluorinates metal fluoride powder through a steam defluorination device, and obtains metal oxide powder after cooling through a cooling device, thereby realizing the recycling of resources.
One of the purposes of the invention is realized by adopting the following technical scheme:
A process for recycling nitrogen trifluoride electrolysis residues comprises the following steps:
1) Crushing the electrolytic nitrogen trifluoride residues;
2) Feeding the crushed residues to a high-temperature anaerobic pyrolysis device for high-temperature anaerobic pyrolysis to obtain pyrolyzed gas and powder; wherein the powder is a metal fluoride powder;
3) Condensing the pyrolyzed gas to obtain condensate and non-condensable gas, crystallizing the condensate to obtain ammonium bifluoride, and introducing the non-condensable gas into a container filled with calcium oxide to generate calcium fluoride; the reaction equation is: 2hf+ca (OH) 2＝CaF2↓+2H2 O.
4) Introducing high-temperature steam into pyrolyzed metal fluoride powder for defluorination, and introducing the high-temperature steam after defluorination into a container filled with ammonia water for absorbing fluorine gas after heat exchange treatment; and cooling the solid to obtain metal oxide powder, wherein the metal oxide powder contains 70-80% of nickel oxide, and the balance of iron oxide, copper oxide or other impurities.
Further, in the step 2), the high-temperature anaerobic pyrolysis temperature is 400-600 ℃, preferably 500 ℃, because the metal corrosiveness is accelerated at high temperature, the 400-600 ℃ can not only meet the pyrolysis process, but also properly prolong the corrosion-resistant life of the metal, and the 500 ℃ is selected to enable the ammonium bifluoride and the hydrogen fluoride to be completely pyrolyzed, and properly reduce the energy consumption.
In the step 3), water cooling is adopted for condensation crystallization, the water cooling is normal-temperature tap water, and the tap water is cooled by an air cooling heat exchanger, so that the recycling is realized.
Further, in step 4), the temperature of the high temperature steam is 400 to 600 ℃, preferably 500 ℃.
In step 4), excessive ammonia water is selected to absorb the fluorine gas after heat exchange. 2NH 3+3F2＝N2+6HFNH3 as the ammonia water just reacted; excess ammonia water with sufficient quantity of 8NH 3+3F2＝N2+6NH4FF2; excess ammonia, NH 3+3F2＝NF3 +3HF. The excess ammonia can completely reduce the hydrogen fluoride.
The second purpose of the invention is realized by adopting the following technical scheme:
The equipment for recycling the resources of the electrolytic residues of nitrogen trifluoride comprises a crushing device, a feeding device, a high-temperature anaerobic pyrolysis device, a condensing device, a crystallization device, a calcium oxide tank, a steam defluorination device, an ammonia water tank, a heat exchange device and a cooling device;
the discharging hole of the crushing device is connected with the feeding hole of the feeding device, the discharging hole of the feeding device is connected with the feeding hole of the high-temperature anaerobic pyrolysis device, the air outlet of the high-temperature anaerobic pyrolysis device is connected with the air inlet of the condensing device, the condensate outlet of the condensing device is connected with the condensate inlet of the crystallizing device, and the non-condensable gas outlet of the condensing device is connected with the non-condensable gas inlet of the calcium oxide tank;
the discharge port of the high-temperature anaerobic pyrolysis device is connected with the feed port of the steam defluorination device, and high-temperature steam circulates in the steam defluorination device; the steam outlet of the steam defluorination device is connected with the steam inlet of the heat exchange device, the air outlet of the heat exchange device is connected with the air inlet of the ammonia water tank, and the discharge port of the steam defluorination device is connected with the cooling device.
Further, the feeding device comprises a hopper, a material pipe and a spiral feeding machine, wherein the hopper is connected with the spiral feeding machine through the material pipe; the material pipe is provided with a material level gauge and a plurality of valves, and the valves are used for sealing in a segmented manner in the feeding stage, so that air in the material pipe is pumped out, and the gas in the high-temperature anaerobic pyrolysis device is prevented from recharging the feeding device.
Still further, the high temperature anaerobic pyrolysis device is a molten salt heating furnace or an electric heating furnace.
Further, the equipment also comprises a vacuum pump, and the vacuum pump is connected with the high-temperature anaerobic pyrolysis device, so that the high-temperature anaerobic pyrolysis device is in an anaerobic vacuum state, and oxygen mixing in the pyrolysis process is reduced; the condensing device is a scraper condenser.
Still further, the equipment still includes discharging device, and discharging device is including water-cooling screw conveyer and the feed bin that connects gradually, and water-cooling screw conveyer is equipped with the cooling water export, water-cooling screw conveyer's cooling water export and entry with cooling device circulation is connected.
Compared with the prior art, the invention has the beneficial effects that:
(1) The main contaminants in the electrolytic residues of nitrogen trifluoride are known as ammonium bifluoride, hydrogen fluoride and metal fluorides, the boiling point of ammonium bifluoride being 240 ℃ and the boiling point of hydrogen fluoride being 19.51 ℃. The invention relates to a process for recycling resources of electrolytic residues of nitrogen trifluoride, which comprises the steps of firstly crushing the electrolytic residues, then carrying out high-temperature anaerobic pyrolysis, changing most of ammonium bifluoride and hydrogen fluoride into steam, reserving metal fluoride in a powdery form, introducing the steam after pyrolysis into a condensing device, condensing condensate liquid into ammonium bifluoride, crystallizing non-condensable gas into hydrogen fluoride, and recycling to obtain ammonium bifluoride solid; introducing the non-condensable hydrogen fluoride gas into a container filled with calcium oxide to react to generate calcium fluoride; completely defluorinating the pyrolyzed metal fluoride powder by high-temperature steam to obtain metal oxide powder; the defluorinated steam is absorbed by ammonia water after heat exchange treatment, so as to prevent fluorine gas from escaping and polluting the environment, and the defluorinated metal oxide powder is recovered after cooling. The invention utilizes the gas-solid-liquid phase change characteristics of ammonium bifluoride, hydrogen fluoride and metal fluoride at different temperatures, thereby realizing the separation and resource recovery of ammonium bifluoride, hydrogen fluoride and metal oxide in the electrolytic residue of nitrogen trifluoride, and the main components of nickel oxide (80-85%), iron oxide and copper oxide in the obtained metal oxide powder also have a small amount (1-2%) of impurities.
Compared with the prior art, the process has the following advantages: firstly, no pollution, no other materials are added, no other materials are generated, thirdly, no ammonia water or hydrofluoric acid and other materials are added, and the cost of the added materials and the energy consumption of the added materials in the evaporation and concentration processes are not increased; 4. compared with the prior art, the method has cleaner and thorough treatment, the overall content of hydrogen fluoride and ammonium bifluoride contained in the pyrolyzed metal fluoride powder is 2-3%, and the content of the prior art is more than 20%; 5. the metal fluoride contains 50-60% of nickel fluoride, and is oxidized into nickel oxide after steam defluorination, so that the nickel oxide is purified and recycled, and the application value is increased; 6. the labor is reduced.
(2) The equipment for recycling the nitrogen trifluoride electrolytic residue resource comprises a crushing device, a feeding device, a high-temperature anaerobic pyrolysis device, a condensing device, a crystallization device, a calcium oxide tank, a steam defluorination device, a heat exchange device, an ammonia water tank and a cooling device; the electrolytic residues firstly pass through a crushing device and then are sent to a high-temperature anaerobic pyrolysis device by a feeding device, the high-temperature anaerobic pyrolysis device is used for gasifying most of ammonium bifluoride and hydrogen fluoride into steam, metal fluoride is reserved in a powder form, and a condensing device is used for condensing the steam to obtain condensate (ammonium bifluoride) and noncondensable gas (hydrogen fluoride); the crystallization device is used for crystallizing and recycling condensate liquid to obtain ammonium bifluoride, and the calcium oxide tank is used for reacting with non-condensable gas (hydrogen fluoride) to obtain calcium fluoride; the steam defluorination device is used for heating and defluorinating the metal fluoride in the pyrolyzed metal fluoride powder by steam to obtain metal oxide powder; the heat exchange device is used for carrying out heat exchange with the high-temperature steam after defluorination to cool the high-temperature steam; the ammonia water tank is used for absorbing fluorine gas of defluorinated steam after heat exchange; the cooling device is used for cooling the defluorinated metal oxide powder. The equipment provided by the invention realizes the resource recovery and clean production of ammonium bifluoride, hydrogen fluoride and metal oxide, the resource recycling, the energy consumption and the labor cost are reduced, and the recovery rate is improved.
(3) The invention does not need low-temperature concentration and evaporation crystallization (the energy consumption of compressor condensation), both the condensation and crystallization adopt water cooling, and the cooling device is cooled by tap water in the outer jacket of the water cooling screw conveyor, so that the energy consumption and labor are reduced by more than 50%.
Drawings
FIG. 1 is a schematic view of the apparatus of example 1;
FIG. 2 is a schematic view of the apparatus of examples 2 to 5.
In the figure: 1. a hopper; 2. a material pipe; 3. a valve; 4. a level gauge; 5. a spiral feeder; 6. a high temperature anaerobic pyrolysis device; 7. star discharger; 8. a steam defluorination device; 9. a cooling device; 10. a water-cooled screw conveyor; 11. a storage bin; 12. cracking an air outlet pipe; 13. a crystallization device; 14. a condensing device; 15. a vacuum pump; 16. a calcium oxide tank; 17. a condensate inlet; 18. a condensate outlet; 19. a condensate pump; 20. a control cabinet; 21. and a heat exchange device.
Detailed Description
The present invention will be further described with reference to the accompanying drawings and detailed description, wherein it is to be understood that, on the premise of no conflict, the following embodiments or technical features may be arbitrarily combined to form new embodiments.
Ammonium bifluoride is an inorganic substance, the molecular formula is NH 4HF2, white or colorless transparent orthorhombic crystal is formed, the commodity is in a sheet shape, slightly sour, the relative density is 1.52, the melting point is 124.6 ℃, and the boiling point is 240 ℃.
Hydrogen fluoride is an inorganic acid with chemical formula of HF, density of 0.922kg, melting point of-83.37deg.C, boiling point of 19.51deg.C
Example 1
The equipment for recycling the resources of the electrolytic residues of nitrogen trifluoride comprises a crushing device, a feeding device, a high-temperature anaerobic pyrolysis device 6, a condensing device 14, a crystallization device 13, a calcium oxide tank 16, a steam defluorination device 8, an ammonia water tank, a heat exchange device 21 and a cooling device 9, wherein the use method of the equipment is as in the process for recycling the resources of the electrolytic residues of nitrogen trifluoride; the devices are controlled to operate through a control cabinet 20;
the discharge port of the crushing device is connected with the feed port of the feeding device, the discharge port of the feeding device is connected with the feed port of the high-temperature anaerobic pyrolysis device 6, the gas outlet of the high-temperature anaerobic pyrolysis device 6 is connected with the gas inlet of the condensing device 14 through the cracking gas outlet pipe 12, the condensate outlet 18 of the condensing device 14 is connected with the condensate inlet 17 of the crystallizing device 13 through the condensate pump 19, and the non-condensable gas outlet of the condensing device 14 is connected with the non-condensable gas inlet of the calcium oxide tank 16 through the vacuum pump 15;
The discharge port of the high-temperature anaerobic pyrolysis device 6 is connected with the feed port of the steam defluorination device 8 through a star discharger 7, and high-temperature steam circulates in the steam defluorination device 8; the steam outlet of the steam defluorination device 8 is connected with the steam inlet of the heat exchange device 21, the air outlet of the heat exchange device 21 is connected with the air inlet of the ammonia water tank, and the discharge outlet of the steam defluorination device 8 is connected with the cooling device 9.
The feeding device comprises a hopper 1, a material pipe 2 and a spiral feeding machine 5, wherein the hopper 1 is connected with the spiral feeding machine 5 through the material pipe 2; the material pipe 2 is provided with a material level gauge 4 and a plurality of valves 3, and in the feeding stage, the valves 3 are used for sealing in a segmented manner to pump out the air in the material pipe. The high-temperature anaerobic pyrolysis device 6 is a molten salt heating furnace or an electric heating furnace, and the inner container of the heating furnace is respectively provided with a pressure gauge, a safety valve, an air outlet pipe, a discharging pipe 2 and the like. The condensing device 14 is a wiped film condenser.
A process for recycling nitrogen trifluoride electrolysis residues comprises the following steps:
1) Crushing the electrolytic nitrogen trifluoride residues by a shredder to obtain particles with the diameter of less than 20 mm;
2) Delivering the crushed residues into a high-temperature anaerobic pyrolysis device 6 through a feeding device, and performing high-temperature anaerobic pyrolysis at 500 ℃ to obtain pyrolyzed gas and powder; the powder is metal fluoride powder, water cooling is adopted for condensation crystallization, the water cooling is normal-temperature tap water, and the tap water is cooled by an air cooling heat exchanger, so that the recycling is realized;
3) The pyrolyzed gas is added into a condensing device 14 to be condensed to obtain condensate and non-condensable gas, the condensate enters a crystallization device 13 to obtain ammonium bifluoride, and the non-condensable gas is pumped into a calcium oxide tank 16 through a vacuum pump 15 to generate calcium fluoride;
4) Introducing high-temperature steam at 400 ℃ into a steam defluorination device 8 for defluorination, introducing the defluorinated high-temperature steam into a heat exchange device 21 for heat exchange treatment, and then introducing the high-temperature steam into an ammonia tank for absorbing fluorine gas; and cooling the solid to obtain metal oxide powder, wherein the main component of the metal oxide is nickel oxide.
Example 2
The equipment for recycling the resources of the electrolytic residues of nitrogen trifluoride comprises a crushing device, a feeding device, a high-temperature anaerobic pyrolysis device 6, a condensing device 14, a crystallization device 13, a calcium oxide tank 16, a steam defluorination device 8, an ammonia tank, a cooling device 9, a heat exchange device 21 and a discharging device, wherein the use method of the equipment is as described in the process for recycling the resources of the electrolytic residues of nitrogen trifluoride; the devices are controlled to operate through a control cabinet 20;
the discharge port of the crushing device is connected with the feed port of the feeding device, the discharge port of the feeding device is connected with the feed port of the high-temperature anaerobic pyrolysis device 6, the gas outlet of the high-temperature anaerobic pyrolysis device 6 is connected with the gas inlet of the condensing device 14 through the cracking gas outlet pipe 12, the condensate outlet 18 of the condensing device 14 is connected with the condensate inlet 17 of the crystallizing device 13 through the condensate pump 19, and the non-condensable gas outlet of the condensing device 14 is connected with the non-condensable gas inlet of the calcium oxide tank 16 through the vacuum pump 15;
The discharge port of the high-temperature anaerobic pyrolysis device 6 is connected with the feed port of the steam defluorination device 8 through a star discharger 7, and high-temperature steam circulates in the steam defluorination device 8; the steam outlet of the steam defluorination device 8 is connected with the steam inlet of the heat exchange device 21, the air outlet of the heat exchange device 21 is connected with the air inlet of the ammonia water tank, and the discharge port of the steam defluorination device 8 is connected with the cooling device 9; the discharging device comprises a water-cooling screw conveyor 10 and a storage bin 11 which are sequentially connected, and a cooling water outlet and an inlet of the water-cooling screw conveyor 10 are circularly connected with the cooling device 9.
The feeding device comprises a hopper 1, a material pipe 2 and a spiral feeding machine 5, wherein the hopper 1 is connected with the spiral feeding machine 5 through the material pipe 2; the material pipe 2 is provided with a material level gauge 4 and a plurality of valves 3, and in the feeding stage, the valves 3 are used for sealing in a segmented manner to pump out the air in the material pipe. The high-temperature anaerobic pyrolysis device 6 is a molten salt heating furnace or an electric heating furnace, and the inner container of the heating furnace is respectively provided with a pressure gauge, a safety valve, an air outlet pipe, a discharging pipe 2 and the like. The condensing device 14 is a wiped film condenser.
A process for recycling nitrogen trifluoride electrolysis residues comprises the following steps:
1) Crushing the electrolytic nitrogen trifluoride residues by a shredder to obtain particles with the diameter of less than 20 mm;
2) Delivering the crushed residues into a high-temperature anaerobic pyrolysis device 6 through a feeding device, and performing high-temperature anaerobic pyrolysis at 400 ℃ to obtain pyrolyzed gas and powder; the powder is metal fluoride powder, water cooling is adopted for condensation crystallization, the water cooling is normal-temperature tap water, and the tap water is cooled by an air cooling heat exchanger, so that the recycling is realized;
3) The pyrolyzed gas is added into a condensing device 14 to be condensed to obtain condensate and non-condensable gas, the condensate enters a crystallization device 13 to obtain ammonium bifluoride, and the non-condensable gas is pumped into a calcium oxide tank 16 through a vacuum pump 15 to generate calcium fluoride;
4) Introducing 600 ℃ high-temperature steam into a steam defluorination device 8 for defluorination, introducing the defluorinated high-temperature steam into a heat exchange device 21 for heat exchange treatment, and then introducing the high-temperature steam into an ammonia tank for absorbing fluorine gas; the solid is cooled to obtain metal oxide powder, and the main component in the metal oxide is nickel oxide;
5) The metal oxide powder is sent to a discharging device and is sent to a storage bin 11 for storage through a water-cooling screw conveyor 10.
Example 3
The apparatus of example 3 was identical to example 2, with the specific process being different.
The process for recycling the nitrogen trifluoride electrolytic residue resource in the embodiment comprises the following steps:
1) Crushing the electrolytic nitrogen trifluoride residues by a shredder to obtain particles with the diameter of less than 20 mm;
2) Delivering the crushed residues into a high-temperature anaerobic pyrolysis device 6 through a feeding device, and performing high-temperature anaerobic pyrolysis at 600 ℃ to obtain pyrolyzed gas and powder; the powder is metal fluoride powder, water cooling is adopted for condensation crystallization, the water cooling is normal-temperature tap water, and the tap water is cooled by an air cooling heat exchanger, so that the recycling is realized;
3) The pyrolyzed gas is added into a condensing device 14 to be condensed to obtain condensate and non-condensable gas, the condensate enters a crystallization device 13 to obtain ammonium bifluoride, and the non-condensable gas is pumped into a calcium oxide tank 16 through a vacuum pump 15 to generate calcium fluoride;
4) Introducing high-temperature steam at 500 ℃ into a steam defluorination device 8 for defluorination, introducing the defluorinated high-temperature steam into a heat exchange device 21 for heat exchange treatment, and then introducing the high-temperature steam into an ammonia tank for absorbing fluorine gas; the solid is cooled to obtain metal oxide powder, and the main component in the metal oxide is nickel oxide;
5) The metal oxide powder is sent to a discharging device and is sent to a storage bin 11 for storage through a water-cooling screw conveyor 10.
Performance and testing
The process and apparatus of examples 1 to 3 were used to treat nitrogen trifluoride electrolysis residue resources, and the contents of hydrogen fluoride and ammonium bifluoride in the metal fluoride powder, and the mass ratio of nickel oxide in the metal oxide powder were examined, as shown in Table 1.
Table 1 data on the mass ratio of the contents of hydrogen fluoride and ammonium bifluoride in the metal oxide powders and nickel oxide-nickel oxide in the metal oxide powders in each group
As is clear from Table 1, the overall content of hydrogen fluoride and ammonium bifluoride in the metal fluoride powder after the apparatus and process treatments of examples 1 to 3 is only 1 to 2%, while the proportion of nickel oxide in the metal oxide powder is at most 85%, so that the separation of the metal fluoride from hydrogen fluoride and ammonium bifluoride is realized, and the subsequent operations can recover hydrogen fluoride, ammonium bifluoride and nickel oxide, and can also improve the purity of nickel oxide.
The above embodiments are only preferred embodiments of the present invention, and the scope of the present invention is not limited thereto, but any insubstantial changes and substitutions made by those skilled in the art on the basis of the present invention are intended to be within the scope of the present invention as claimed.
Claims (9)
1. The process for recycling the nitrogen trifluoride electrolysis residue resource is characterized by comprising the following steps of:
1) Crushing the electrolytic nitrogen trifluoride residues;
2) Feeding the crushed residues to a high-temperature anaerobic pyrolysis device for high-temperature anaerobic pyrolysis to obtain pyrolyzed gas and powder; wherein the powder is a metal fluoride powder;
3) Condensing the pyrolyzed gas to obtain condensate and non-condensable gas, crystallizing the condensate to obtain ammonium bifluoride, and introducing the non-condensable gas into a container filled with calcium oxide to generate calcium fluoride;
4) Introducing high-temperature steam into pyrolyzed metal fluoride powder for defluorination, and introducing the high-temperature steam after defluorination into a container filled with ammonia water for absorbing fluorine gas after heat exchange treatment; and cooling the solid to obtain metal oxide powder.
2. The process for the recovery of resources of nitrogen trifluoride electrolysis residues according to claim 1, wherein in step 2), the temperature of the high temperature anaerobic pyrolysis is 400 to 600 ℃.
3. The process for recycling the nitrogen trifluoride electrolysis residues according to claim 1, wherein in the step 3), water cooling is adopted for condensation and crystallization, and the water cooling is normal-temperature tap water.
4. The process for the recovery of resources of nitrogen trifluoride electrolysis residues according to claim 1, wherein in step 4), the temperature of the high temperature steam is 400 to 600 ℃.
5. The process for the recovery of resources from nitrogen trifluoride electrolysis residues according to claim 1, wherein in step 4) an excess of ammonia is selected for the absorption of said fluorine gas.
6. An apparatus for recovering resources of electrolytic nitrogen trifluoride residue, characterized in that the method of using the apparatus is a process for recovering resources of electrolytic nitrogen trifluoride residue according to any one of claims 1 to 5, the apparatus comprising a pulverizing device, a feeding device, a high-temperature anaerobic pyrolysis device, a condensing device, a crystallizing device, a calcium oxide tank, a steam defluorination device, an ammonia water tank, a heat exchange device and a cooling device;
the discharging hole of the crushing device is connected with the feeding hole of the feeding device, the discharging hole of the feeding device is connected with the feeding hole of the high-temperature anaerobic pyrolysis device, the air outlet of the high-temperature anaerobic pyrolysis device is connected with the air inlet of the condensing device, the condensate outlet of the condensing device is connected with the condensate inlet of the crystallizing device, and the non-condensable gas outlet of the condensing device is connected with the non-condensable gas inlet of the calcium oxide tank;
The discharge port of the high-temperature anaerobic pyrolysis device is connected with the feed port of the steam defluorination device, and high-temperature steam circulates in the steam defluorination device; the steam outlet of the steam defluorination device is connected with the steam inlet of the heat exchange device, the air outlet of the heat exchange device is connected with the air inlet of the ammonia water tank, and the discharge port of the steam defluorination device is connected with the cooling device;
the equipment also comprises a vacuum pump, wherein the vacuum pump is connected with the high-temperature anaerobic pyrolysis device; the condensing device is a scraper condenser.
7. The apparatus for recycling of nitrogen trifluoride electrolytic residue resources according to claim 6, wherein the feeding device comprises a hopper, a material pipe and a screw feeder, and the hopper is connected with the screw feeder through the material pipe; the material pipe is provided with a material level gauge and a plurality of valves.
8. The apparatus for resource recovery of nitrogen trifluoride electrolytic residue as claimed in claim 6, wherein the high temperature anaerobic pyrolysis device is a molten salt heating furnace or an electric heating furnace.
9. The apparatus for recycling of resources of electrolytic nitrogen trifluoride residues according to claim 6, further comprising a discharging device, wherein the discharging device comprises a water-cooled screw conveyor and a storage bin which are sequentially connected, the water-cooled screw conveyor is provided with a cooling water outlet, and the cooling water outlet and the inlet of the water-cooled screw conveyor are circularly connected with the cooling device.
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