CN115557872A - NMP waste liquid recovery treatment method - Google Patents
NMP waste liquid recovery treatment method Download PDFInfo
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- CN115557872A CN115557872A CN202211355387.3A CN202211355387A CN115557872A CN 115557872 A CN115557872 A CN 115557872A CN 202211355387 A CN202211355387 A CN 202211355387A CN 115557872 A CN115557872 A CN 115557872A
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- iron phosphate
- lithium iron
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- 239000002699 waste material Substances 0.000 title claims abstract description 110
- 239000007788 liquid Substances 0.000 title claims abstract description 71
- 238000000034 method Methods 0.000 title claims abstract description 55
- 238000011084 recovery Methods 0.000 title claims description 17
- GELKBWJHTRAYNV-UHFFFAOYSA-K lithium iron phosphate Chemical compound [Li+].[Fe+2].[O-]P([O-])([O-])=O GELKBWJHTRAYNV-UHFFFAOYSA-K 0.000 claims abstract description 60
- 239000000463 material Substances 0.000 claims abstract description 27
- 238000009833 condensation Methods 0.000 claims abstract description 26
- 230000005494 condensation Effects 0.000 claims abstract description 26
- 238000004064 recycling Methods 0.000 claims abstract description 20
- 238000011069 regeneration method Methods 0.000 claims abstract description 17
- 238000010438 heat treatment Methods 0.000 claims abstract description 16
- 238000005516 engineering process Methods 0.000 claims abstract description 12
- 230000009467 reduction Effects 0.000 claims abstract description 12
- 239000007790 solid phase Substances 0.000 claims abstract description 12
- 238000000926 separation method Methods 0.000 claims abstract description 10
- 230000008929 regeneration Effects 0.000 claims abstract description 9
- 239000012267 brine Substances 0.000 claims abstract description 6
- HPALAKNZSZLMCH-UHFFFAOYSA-M sodium;chloride;hydrate Chemical compound O.[Na+].[Cl-] HPALAKNZSZLMCH-UHFFFAOYSA-M 0.000 claims abstract description 6
- 238000004364 calculation method Methods 0.000 claims abstract description 5
- SECXISVLQFMRJM-UHFFFAOYSA-N N-Methylpyrrolidone Chemical compound CN1CCCC1=O SECXISVLQFMRJM-UHFFFAOYSA-N 0.000 claims abstract 23
- 239000012535 impurity Substances 0.000 claims description 31
- 239000002994 raw material Substances 0.000 claims description 22
- 239000000126 substance Substances 0.000 claims description 19
- 239000007789 gas Substances 0.000 claims description 17
- 238000003825 pressing Methods 0.000 claims description 17
- 230000008569 process Effects 0.000 claims description 17
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 14
- XLOMVQKBTHCTTD-UHFFFAOYSA-N Zinc monoxide Chemical compound [Zn]=O XLOMVQKBTHCTTD-UHFFFAOYSA-N 0.000 claims description 14
- 229910052799 carbon Inorganic materials 0.000 claims description 14
- 239000002033 PVDF binder Substances 0.000 claims description 13
- JEIPFZHSYJVQDO-UHFFFAOYSA-N iron(III) oxide Inorganic materials O=[Fe]O[Fe]=O JEIPFZHSYJVQDO-UHFFFAOYSA-N 0.000 claims description 13
- 238000001291 vacuum drying Methods 0.000 claims description 13
- 229920002981 polyvinylidene fluoride Polymers 0.000 claims description 12
- 239000002243 precursor Substances 0.000 claims description 11
- 229920006395 saturated elastomer Polymers 0.000 claims description 11
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 claims description 10
- 229910052744 lithium Inorganic materials 0.000 claims description 10
- 239000010405 anode material Substances 0.000 claims description 9
- 238000012216 screening Methods 0.000 claims description 9
- 239000002912 waste gas Substances 0.000 claims description 9
- 229910012425 Li3Fe2 (PO4)3 Inorganic materials 0.000 claims description 8
- 239000006256 anode slurry Substances 0.000 claims description 8
- 239000000843 powder Substances 0.000 claims description 8
- 239000002002 slurry Substances 0.000 claims description 8
- 229910052493 LiFePO4 Inorganic materials 0.000 claims description 7
- 239000007806 chemical reaction intermediate Substances 0.000 claims description 7
- 238000004140 cleaning Methods 0.000 claims description 7
- 239000003792 electrolyte Substances 0.000 claims description 7
- 238000004519 manufacturing process Methods 0.000 claims description 7
- 238000004537 pulping Methods 0.000 claims description 7
- 239000012808 vapor phase Substances 0.000 claims description 7
- 239000011787 zinc oxide Substances 0.000 claims description 7
- 229910000901 LiFePO4/C Inorganic materials 0.000 claims description 6
- 229910052782 aluminium Inorganic materials 0.000 claims description 6
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 claims description 6
- 239000007791 liquid phase Substances 0.000 claims description 6
- 239000012855 volatile organic compound Substances 0.000 claims description 5
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims description 4
- 238000001354 calcination Methods 0.000 claims description 4
- 238000001035 drying Methods 0.000 claims description 4
- 239000000203 mixture Substances 0.000 claims description 4
- 238000004321 preservation Methods 0.000 claims description 4
- 239000000047 product Substances 0.000 claims description 4
- 239000002893 slag Substances 0.000 claims description 4
- 239000006228 supernatant Substances 0.000 claims description 4
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 claims description 3
- HCHKCACWOHOZIP-UHFFFAOYSA-N Zinc Chemical compound [Zn] HCHKCACWOHOZIP-UHFFFAOYSA-N 0.000 claims description 3
- 229910052802 copper Inorganic materials 0.000 claims description 3
- 239000010949 copper Substances 0.000 claims description 3
- UQSXHKLRYXJYBZ-UHFFFAOYSA-N iron oxide Inorganic materials [Fe]=O UQSXHKLRYXJYBZ-UHFFFAOYSA-N 0.000 claims description 3
- 230000003647 oxidation Effects 0.000 claims description 3
- 238000007254 oxidation reaction Methods 0.000 claims description 3
- TWNQGVIAIRXVLR-UHFFFAOYSA-N oxo(oxoalumanyloxy)alumane Chemical compound O=[Al]O[Al]=O TWNQGVIAIRXVLR-UHFFFAOYSA-N 0.000 claims description 3
- NDLPOXTZKUMGOV-UHFFFAOYSA-N oxo(oxoferriooxy)iron hydrate Chemical compound O.O=[Fe]O[Fe]=O NDLPOXTZKUMGOV-UHFFFAOYSA-N 0.000 claims description 3
- 230000001376 precipitating effect Effects 0.000 claims description 3
- 229910052725 zinc Inorganic materials 0.000 claims description 3
- 239000011701 zinc Substances 0.000 claims description 3
- 229910052757 nitrogen Inorganic materials 0.000 claims description 2
- 238000011085 pressure filtration Methods 0.000 claims description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims 2
- 229910019142 PO4 Inorganic materials 0.000 claims 1
- 239000010808 liquid waste Substances 0.000 claims 1
- 229910001386 lithium phosphate Inorganic materials 0.000 claims 1
- NBIIXXVUZAFLBC-UHFFFAOYSA-K phosphate Chemical compound [O-]P([O-])([O-])=O NBIIXXVUZAFLBC-UHFFFAOYSA-K 0.000 claims 1
- 239000010452 phosphate Substances 0.000 claims 1
- 239000007774 positive electrode material Substances 0.000 claims 1
- TWQULNDIKKJZPH-UHFFFAOYSA-K trilithium;phosphate Chemical compound [Li+].[Li+].[Li+].[O-]P([O-])([O-])=O TWQULNDIKKJZPH-UHFFFAOYSA-K 0.000 claims 1
- 230000001590 oxidative effect Effects 0.000 description 4
- NCZYUKGXRHBAHE-UHFFFAOYSA-K [Li+].P(=O)([O-])([O-])[O-].[Fe+2].[Li+] Chemical compound [Li+].P(=O)([O-])([O-])[O-].[Fe+2].[Li+] NCZYUKGXRHBAHE-UHFFFAOYSA-K 0.000 description 3
- 238000003860 storage Methods 0.000 description 3
- 239000005955 Ferric phosphate Substances 0.000 description 2
- 230000003139 buffering effect Effects 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 229940032958 ferric phosphate Drugs 0.000 description 2
- 238000000227 grinding Methods 0.000 description 2
- WBJZTOZJJYAKHQ-UHFFFAOYSA-K iron(3+) phosphate Chemical compound [Fe+3].[O-]P([O-])([O-])=O WBJZTOZJJYAKHQ-UHFFFAOYSA-K 0.000 description 2
- 229910000399 iron(III) phosphate Inorganic materials 0.000 description 2
- 229910052751 metal Inorganic materials 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- 238000002156 mixing Methods 0.000 description 2
- 238000000746 purification Methods 0.000 description 2
- 239000000243 solution Substances 0.000 description 2
- 238000005406 washing Methods 0.000 description 2
- VTLYFUHAOXGGBS-UHFFFAOYSA-N Fe3+ Chemical compound [Fe+3] VTLYFUHAOXGGBS-UHFFFAOYSA-N 0.000 description 1
- 230000009471 action Effects 0.000 description 1
- 230000004075 alteration Effects 0.000 description 1
- WPPDFTBPZNZZRP-UHFFFAOYSA-N aluminum copper Chemical compound [Al].[Cu] WPPDFTBPZNZZRP-UHFFFAOYSA-N 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000009835 boiling Methods 0.000 description 1
- 239000011248 coating agent Substances 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000001514 detection method Methods 0.000 description 1
- 238000007599 discharging Methods 0.000 description 1
- 239000013072 incoming material Substances 0.000 description 1
- 231100000053 low toxicity Toxicity 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 239000003960 organic solvent Substances 0.000 description 1
- 239000012071 phase Substances 0.000 description 1
- 239000003880 polar aprotic solvent Substances 0.000 description 1
- 238000005086 pumping Methods 0.000 description 1
- 230000001172 regenerating effect Effects 0.000 description 1
- 239000013049 sediment Substances 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- 230000001502 supplementing effect Effects 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07D—HETEROCYCLIC COMPOUNDS
- C07D207/00—Heterocyclic compounds containing five-membered rings not condensed with other rings, with one nitrogen atom as the only ring hetero atom
- C07D207/02—Heterocyclic compounds containing five-membered rings not condensed with other rings, with one nitrogen atom as the only ring hetero atom with only hydrogen or carbon atoms directly attached to the ring nitrogen atom
- C07D207/18—Heterocyclic compounds containing five-membered rings not condensed with other rings, with one nitrogen atom as the only ring hetero atom with only hydrogen or carbon atoms directly attached to the ring nitrogen atom having one double bond between ring members or between a ring member and a non-ring member
- C07D207/22—Heterocyclic compounds containing five-membered rings not condensed with other rings, with one nitrogen atom as the only ring hetero atom with only hydrogen or carbon atoms directly attached to the ring nitrogen atom having one double bond between ring members or between a ring member and a non-ring member with hetero atoms or with carbon atoms having three bonds to hetero atoms with at the most one bond to halogen, e.g. ester or nitrile radicals, directly attached to ring carbon atoms
- C07D207/24—Oxygen or sulfur atoms
- C07D207/26—2-Pyrrolidones
- C07D207/263—2-Pyrrolidones with only hydrogen atoms or radicals containing only hydrogen and carbon atoms directly attached to other ring carbon atoms
- C07D207/267—2-Pyrrolidones with only hydrogen atoms or radicals containing only hydrogen and carbon atoms directly attached to other ring carbon atoms with only hydrogen atoms or radicals containing only hydrogen and carbon atoms directly attached to the ring nitrogen atom
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
- C01B25/00—Phosphorus; Compounds thereof
- C01B25/16—Oxyacids of phosphorus; Salts thereof
- C01B25/26—Phosphates
- C01B25/45—Phosphates containing plural metal, or metal and ammonium
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
- C01G49/00—Compounds of iron
- C01G49/02—Oxides; Hydroxides
- C01G49/06—Ferric oxide [Fe2O3]
-
- 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
- Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
- Y02W30/00—Technologies for solid waste management
- Y02W30/50—Reuse, recycling or recovery technologies
- Y02W30/84—Recycling of batteries or fuel cells
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Inorganic Chemistry (AREA)
- Primary Cells (AREA)
Abstract
The invention discloses a method for recycling and treating waste NMP (N-methyl pyrrolidone) liquid, which comprises the steps of adding a two-stage condensation technology through autonomous calculation under a two-stage condensation recycling device system through self-developed solid-liquid separation equipment, introducing frozen brine to realize NMP recycling, placing recycled positive plates in a tubular furnace through a waste lithium iron phosphate material carbothermic reduction solid-phase regeneration method by adopting a heat treatment method, and separating and impurity-removing regeneration by utilizing waste lithium iron phosphate plates.
Description
Technical Field
The invention relates to the technical field of an NMP waste liquid recovery treatment method, in particular to an NMP waste liquid recovery treatment method.
Background
NMP is a polar aprotic solvent, has the advantages of high boiling point, strong neutrality, low toxicity, low volatility, excellent chemical stability and thermal stability, strong dissolving capacity, recyclability and the like, and is an indispensable organic solvent in the lithium battery industry.
In the coating link of lithium battery positive plate production, NMP is used as the main liquid carrier of slurry, and is uniformly coated on the metal base material in a stable thickness, and the metal base material has good wettability and fluidity. Generally, NMP is recovered by washing and condensing in a lithium battery production plant, and NMP waste liquid after washing, condensing and recovering needs to be purified to a component of more than 99.9wt% before being reused. Some electronics industries require higher purity. Therefore, the stable and efficient waste liquid rectification process has an extremely important effect on the recycling of the NMP. At present, common solid-liquid separation of NMP waste liquid only adopts a vacuum drying host, a pipeline and a vacuum pump by utilizing traditional vacuum drying equipment, and cannot meet the existing production requirements.
Disclosure of Invention
Technical problem to be solved
Aiming at the defects of the prior art, the invention provides a method for recovering and treating the NMP waste liquid, which has the advantages of increasing two-stage condensation by utilizing autonomous calculation and introducing frozen brine to realize efficient recovery of NMP and the like, and solves the problems in the background art.
(II) technical scheme
To achieve the objective of solving the problems described in the background art, the present invention provides the following technical solutions: a NMP waste liquid recovery treatment method comprises the following steps:
s1: collecting NMP waste liquid;
s2: extracting the supernatant of the NMP waste liquid;
s3: collecting clear liquid through filter pressing;
s4: precipitating the cake dregs generated after the filter pressing is finished;
s5: treating NMP waste gas through vacuum drying;
s6: purification and recovery of NMP
Preferably, in S1, the lithium iron phosphate battery waste is sorted to obtain a battery waste, a waste anode slurry and an NMP waste liquid, the waste anode slurry is subjected to a carbon thermal reduction solid-phase regeneration method for the waste lithium iron phosphate material, solid-liquid separation is performed to obtain an anode slag and an NMP waste liquid, and the collected NMP waste liquid is stored in a ton bucket.
Preferably, in S3, by using a self-developed solid-liquid separation device, under a two-stage condensation recovery device system, a two-stage condensation technique is added by self-calculation, and a frozen brine is introduced to realize NMP recovery.
Preferably, the scrapped slurry and the cleaning waste generated in the pulping process of the anode material of the lithium iron phosphate battery material production enterprise are used as raw materials, and do not contain impurities such as electrolyte, aluminum and copper, so that the method has the advantages of fixed raw material generation and collection ways and no pollution by other impurities, moisture and NMP are removed through filter pressing and vacuum drying, PVDF is removed through screening, the waste lithium iron phosphate material with high purity can be obtained, further impurity removal such as active aluminum oxide and zinc oxide is not needed to be added, and additional introduction of impurities such as aluminum and zinc is also avoided.
Preferably, in S6, the waste lithium iron phosphate material is pretreated, and then oxidized into reaction intermediates Li3Fe2PO43 and Fe2O3 by a high-temperature oxidation process, and at the same time, impurities such as electrolyte and PVDF can be further removed, and finally a certain amount of lithium source and carbon source are supplemented, and the lithium source and the carbon source are reduced by carbothermic reduction under an inert atmosphere to regenerate LiFePO4/C anode material.
Preferably, the waste lithium iron phosphate material carbon thermal reduction solid-phase regeneration method adopts a heat treatment method to place the recovered positive plate in a tubular furnace, the temperature is raised to 500 ℃ from room temperature, the heat preservation time is 2.5h, liFePO4 is oxidized into Li3Fe2PO43 and Fe2O3, the waste lithium iron phosphate plate is separated and impurity-removed for regeneration, the waste lithium iron phosphate plate is firstly ground, crushed and screened to obtain waste lithium iron phosphate powder, then the waste lithium iron phosphate powder is mixed with active zinc oxide, negative pressure roasting is carried out at 650-675 ℃ to obtain a mixture of ferric oxide and ferric lithium iron phosphate, the raw material is pretreated by processes of filter pressing, drying and the like to remove impurities, then high-temperature subsection calcination or heat treatment at 450-650 ℃ is adopted, and the heat preservation time is carried out for 3h.
Preferably, in S1 to S6, a high-temperature solid-phase regeneration technology is adopted, waste slurry and cleaning waste materials generated in the anode material pulping process of lithium iron phosphate battery enterprises are used as raw materials, after NMP, PVDF, moisture and other impurities are removed through filter pressing, vacuum drying and screening procedures, high-temperature heat treatment is adopted to further remove carbon, residual PVDF, organic matters and other impurities, the purity of the raw materials is improved, unqualified products with the component content not meeting the requirement are removed through detection, the raw material LiFePO4 after impurity removal and purification is oxidized into reaction intermediates Li3Fe2 (PO 4) 3 and Fe2O3 in a rotary furnace, namely a lithium iron phosphate precursor of the technically improved project is prepared, then a lithium source is added, and a lithium iron phosphate rich precursor Li3Fe2PO43+ Fe2O3 which is the same as the raw materials of the existing project is obtained, is added with a carbon source, and then is subjected to high-temperature heat treatment and reduced into LiFePO4/C under the protection of the produced lithium iron phosphate rich precursor, so that the waste lithium iron phosphate 4 is regenerated.
Preferably, the two-stage condensation technology, i.e. the two-stage condensation recovery device system: a substance has different saturated vapor pressures at different temperatures and pressures, when the vapor pressure of the substance reaches the corresponding saturated vapor pressure at a certain temperature, the substance starts to condense, the temperature is called as the dew point temperature of the substance, only if the system temperature is lower than the dew point temperature, the vaporous substance can be condensed from the vapor phase, the condensation method is that the volatile organic compounds have different saturated vapor pressures at different temperatures and pressures, the system temperature is reduced or the system pressure is increased, the substance is converted from the vapor state into the liquid state and is separated from the vapor phase, NMP waste gas in a vacuum drier is cooled to about 40 ℃ through a two-stage condenser, most of NMP is recovered by condensation, a small amount of uncondensed gas enters a vacuum system through the trap, the front end of a vacuum pipeline is provided with a vacuum tail gas trap, the uncondensed vapor is condensed into the liquid phase and flows into a collecting tank, the front end of a liquid tank vacuum pump is provided with a large-volume vacuum buffer tank, and the tail gas is easy to diffuse due to vacuumize, so that the vacuum pipeline is refrigerated, and part of the vacuum tail gas is condensed and flows into the vacuum buffer tank and is periodically discharged as the vacuum liquid.
(III) advantageous effects
Compared with the prior art, the invention provides a method for recovering and treating NMP waste liquid, which has the following beneficial effects:
1. according to the NMP waste liquid recovery treatment method, through the independently researched and developed solid-liquid separation equipment, under a two-stage condensation recovery device system, the two-stage condensation technology is automatically calculated and added, and the frozen brine is introduced, so that NMP recovery is realized, namely the two-stage condensation recovery device system: the condensation method is characterized in that volatile organic compounds have different saturated vapor pressures at different temperatures and pressures, and are converted from a gaseous state to a liquid state to be separated from a gas phase by adopting a mode of reducing the system temperature or increasing the system pressure.
2. The NMP waste liquid recovering and treating process includes cooling NMP waste gas in a vacuum drier to 40 deg.c, condensing to recover most of NMP, trapping small amount of uncondensed gas in a vacuum system, installing tail gas vacuum catcher in the front of the vacuum pipeline to condense uncondensed vapor into liquid phase, flowing the liquid phase into the liquid collecting tank, installing large volume vacuum buffering tank in the front of the vacuum pump, and exhausting.
3. The NMP waste liquid recycling and treating method comprises the steps of placing recycled positive plates in a tubular furnace by a waste lithium iron phosphate material carbothermic reduction solid phase regeneration method, heating the temperature from room temperature to 500 ℃, preserving heat for 2.5 hours, oxidizing LiFePO4 into Li3Fe2PO43 and Fe2O3, utilizing a method for separating and impurity-removing regeneration of the waste lithium iron phosphate plates, grinding and screening the waste lithium iron phosphate plates to obtain waste lithium iron phosphate powder, mixing the waste lithium iron phosphate powder with active zinc oxide, roasting at 650-675 ℃ under negative pressure to obtain a mixture of ferric oxide and ferric phosphate, carrying out pretreatment impurity removal on raw materials by processes of filter pressing, drying and the like, carrying out high-temperature sectional calcination or heat treatment at 450-650 ℃, and preserving heat for 3 hours.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be obtained by a person skilled in the art without making any creative effort based on the embodiments in the present invention, belong to the protection scope of the present invention.
A method for recovering and treating NMP waste liquid comprises the following steps:
s1: collecting NMP waste liquid coming materials, sorting the waste lithium iron phosphate battery materials to obtain battery waste materials, waste anode slurry and NMP waste liquid, carrying out a waste lithium iron phosphate material carbon thermal reduction solid-phase regeneration method on the waste anode slurry, carrying out solid-liquid separation to obtain anode slag materials and NMP waste liquid, carrying out ton barrel storage on the collected NMP waste liquid, taking scrapped slurry and cleaning waste materials generated in the pulping process of the anode materials of lithium iron phosphate battery material production enterprises as raw materials, not containing impurities such as electrolyte, aluminum and copper, and the like, having the advantages of fixed raw material generation and collection ways and not being polluted by other impurities, removing moisture and NMP through filter pressing and vacuum drying, screening to remove PVDF, and obtaining the waste lithium iron phosphate material with extremely high purity, the waste lithium iron phosphate material carbon thermal reduction solid-phase regeneration method comprises the steps of placing a recovered positive plate in a tubular furnace by a heat treatment method, heating the temperature from room temperature to 500 ℃, preserving heat for 2.5 hours, oxidizing LiFePO4 into Li3Fe2 (PO 4) 3 and Fe2O3, utilizing a method for separating and de-doping and regenerating the waste lithium iron phosphate plates, grinding and screening the waste lithium iron phosphate plates to obtain waste lithium iron phosphate powder, mixing the waste lithium iron phosphate powder with active zinc oxide, roasting at 650-675 ℃ under negative pressure to obtain a mixture of ferric iron oxide and ferric phosphate, carrying out pretreatment impurity removal on raw materials by pressure filtration, drying and the like, calcining or carrying out heat treatment at a high temperature of 450-650 ℃ in a segmented manner, and preserving heat for 3 hours;
s2: extracting the supernatant of the NMP waste liquid;
s3: clear liquid is collected through filter pressing, and a two-stage condensation technology is added through autonomous calculation and frozen brine is introduced under a two-stage condensation recovery device system through self-developed solid-liquid separation equipment, so that NMP recovery is realized;
s4: precipitating the cake dregs generated after the filter pressing is finished;
s5: treating the merged NMP waste gas by vacuum drying;
s6: the method comprises the following steps of (1) purifying and recycling NMP, pretreating a waste lithium iron phosphate material, oxidizing the waste lithium iron phosphate material into reaction intermediates Li3Fe2PO43 and Fe2O3 by a high-temperature oxidation process, further removing impurities such as electrolyte and PVDF, finally supplementing a certain amount of lithium source and carbon source, and carrying out carbothermic reduction under an inert atmosphere to regenerate LiFePO4/C anode material, wherein a two-stage condensation technology is a two-stage condensation recycling device system: the condensing method is that volatile organic compounds have different saturated vapor pressures at different temperatures and pressures, the system temperature is lowered or the system pressure is raised to convert the vapor state into liquid state and separate the vapor state from the vapor phase, NMP waste gas in a vacuum drier is first cooled in a two-stage condenser to about 40 deg.c and then condensed to recover most of NMP, small amount of un-condensed gas is trapped in a vacuum system, a vacuum tail gas trap is installed in the front end of the vacuum pipeline to condense the un-condensed vapor into liquid phase and flow into a collecting tank, and a large-volume vacuum buffering tank is installed in the front end of the liquid tank.
The NMP waste liquid recycling method comprises the steps of firstly collecting NMP waste liquid incoming materials, sorting the waste lithium iron phosphate battery waste materials to obtain battery waste materials, waste anode slurry and NMP waste liquid, carrying out waste lithium iron phosphate material carbon thermal reduction solid-phase regeneration on the waste anode slurry, carrying out solid-liquid separation to obtain anode slag materials and the NMP waste liquid, carrying out ton bucket storage on the collected NMP waste liquid, using scrapped slurry generated in the anode material pulping process of lithium iron phosphate battery material production enterprises, using cleaning waste materials as raw materials, and containing no electrolyte, aluminum copper and other impurities, wherein the method has the advantages of raw material generation and collection way fixation, and no pollution by other impurities, and has the advantages of filter pressing, vacuum drying to remove moisture and NMP, screening to remove PVDF (polyvinylidene fluoride), so that the high-purity lithium iron phosphate material can be obtained, no further impurity removal such as active aluminum oxide and zinc oxide is needed to be added, extra introduction of impurities such as aluminum and zinc is avoided, extracting the supernatant of the NMP waste lithium iron phosphate waste liquid, carrying out clear liquid collection through filter pressing, and realizing the independent two-stage condensation technology, and the two-stage condensation technology, namely, and the two-stage condensation system can be used for recycling the waste lithium iron phosphate battery waste lithium iron phosphate: the substance has different saturated vapor pressures at different temperatures and pressures, when the vapor pressure of the substance reaches the corresponding saturated vapor pressure at a certain temperature, the substance starts to condense, the temperature is called the dew point temperature of the substance, only if the system temperature is lower than the dew point temperature, the vapor state substance can be condensed out from the vapor phase, the condensing method is to utilize the property that volatile organic compounds have different saturated vapor pressures at different temperatures and pressures, the vapor state substance is converted from the vapor state into the liquid state and separated from the vapor phase by adopting the mode of reducing the system temperature or increasing the system pressure, the cake sediment generated after filter pressing is precipitated, the NMP waste gas is treated by vacuum drying, after the NMP waste gas in a vacuum drier is cooled to about 40 ℃ by a condenser, most NMP is recovered by utilizing the condensing action, a small amount of uncondensed gas enters a vacuum system by a trap, the vacuum tail gas trap is arranged at the front end of a vacuum pipeline, condensing uncondensed steam into a liquid phase to flow into a liquid collecting tank, mounting a large-volume vacuum buffer tank at the air exhaust front end of a vacuum pump, leading tail gas to be easy to diffuse due to the vacuum pumping, refrigerating a vacuum pipeline, leading partial vacuum tail gas to be condensed to flow into the vacuum buffer tank for storage, periodically discharging vacuum liquid, purifying and recycling NMP, adopting a high-temperature solid phase regeneration technology, taking waste slurry and cleaning waste generated in the anode material pulping process of a lithium iron phosphate battery enterprise as raw materials, carrying out filter pressing, vacuum drying and screening processes for pretreatment to remove impurities such as NMP, PVDF, moisture and the like, then adopting high-temperature heat treatment to further remove impurities such as carbon, residual PVDF, organic matters and the like, improving the purity of the raw materials, detecting and removing unqualified products with unqualified component content which cannot meet the requirements, oxidizing the LiFePO4 which is purified and subjected to impurity removal into reaction intermediates Li3Fe2 (PO 4) 3 and Fe2O3 in a rotary furnace, the lithium iron phosphate precursor of the technically improved project is prepared, then a lithium source is added, the lithium iron phosphate lithium-rich precursor Li3Fe2 (PO 4) 3+ Fe2O3 which is the same as the raw material of the existing project can be obtained, and after the carbon source is added into the produced lithium iron phosphate lithium-rich precursor, the lithium iron phosphate lithium-rich precursor is regenerated through high-temperature heat treatment under the protection of nitrogen and is reduced into LiFePO4/C, and the regeneration of waste lithium iron phosphate LiFePO4 is realized.
Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.
Claims (8)
1. The NMP waste liquid recovery treatment method is characterized by comprising the following steps:
s1: collecting NMP waste liquid;
s2: extracting the supernatant of the NMP waste liquid;
s3: collecting clear liquid through filter pressing;
s4: precipitating the cake dregs generated after the filter pressing is finished;
s5: treating the merged NMP waste gas by vacuum drying;
s6: NMP was purified and recovered.
2. The method for recycling and treating the NMP waste liquid according to claim 1, wherein in S1, the waste lithium iron phosphate battery is sorted to obtain the battery waste, the waste anode slurry and the NMP waste liquid, the waste anode slurry is subjected to a waste lithium iron phosphate material carbothermic reduction solid phase regeneration method, solid-liquid separation is performed to obtain the anode slag and the NMP waste liquid, and the collected NMP waste liquid is stored in a ton bucket.
3. The method for recycling and treating the NMP waste liquid according to claim 1, wherein in the S3, a self-developed solid-liquid separation device is used, so that under a two-stage condensation recycling device system, a two-stage condensation technology is added by self-calculation, and frozen brine is introduced to realize NMP recycling.
4. The method for recycling and treating the NMP waste liquid as claimed in claim 2, wherein waste slurry and cleaning waste materials generated in the positive electrode material pulping process of lithium iron phosphate battery material manufacturing enterprises are used as raw materials, and do not contain impurities such as electrolyte, aluminum, copper and the like, so that the method has the advantages that the raw material generation and collection ways are fixed, and the raw material is not polluted by other impurities, water and NMP are removed through filter pressing and vacuum drying, PVDF is removed through screening, and the waste lithium iron phosphate battery material with extremely high purity can be obtained without adding active aluminum oxide, zinc oxide and the like for further impurity removal, and additional introduction of impurities such as aluminum, zinc and the like is avoided.
5. The method for recycling and treating the NMP waste liquid according to claim 1, wherein in S6, the waste lithium iron phosphate material is pretreated and oxidized into reaction intermediates Li3Fe2 (PO 4) 3 and Fe2O3 by a high-temperature oxidation process, impurities such as electrolyte and PVDF can be further removed, and finally a certain amount of lithium source and carbon source are supplemented, and the reaction intermediates are regenerated into LiFePO4/C anode materials by carbothermic reduction in an inert atmosphere.
6. The method for recycling and treating the NMP waste liquid according to claim 2, wherein the waste lithium iron phosphate material carbothermic reduction solid phase regeneration method adopts a heat treatment method to put a recycled positive plate into a tube furnace, the temperature is raised to 500 ℃ from room temperature, the heat preservation is carried out for 2.5h, the report that LiFePO4 is oxidized into Li3Fe2 (PO 4) 3 and Fe2O3 is carried out, the method for separating and impurity removal regeneration is carried out by utilizing the waste lithium iron phosphate plate, the waste lithium iron phosphate plate is firstly ground, crushed and screened to obtain waste lithium iron phosphate powder, then the waste lithium iron phosphate powder is mixed with active zinc oxide, negative pressure roasting is carried out at 650-675 ℃ to obtain a mixture of ferric oxide and ferric lithium phosphate, after the raw material is pretreated by the processes of pressure filtration, drying and the like to remove impurities, high-temperature sectional calcination or heat treatment at 450-650 ℃ is carried out, and the heat preservation is carried out for 3h.
7. The method for recycling the waste liquid of the NMP as claimed in claim 1, wherein in S1-S6, a high temperature solid phase regeneration technology is adopted, waste slurry and cleaning waste materials generated in the pulping process of the anode materials of lithium iron phosphate battery enterprises are used as raw materials, after pretreatment of filter pressing, vacuum drying and screening processes is carried out to remove impurities such as NMP, PVDF and water, high temperature heat treatment is adopted to further remove impurities such as carbon, residual PVDF and organic matters, the purity of the raw materials is improved, unqualified products with unqualified component content which cannot be detected and removed are detected, liFePO4 which is purified after impurity removal is oxidized into reaction intermediates Li3Fe2 (PO 4) 3 and Fe2O3 in a rotary furnace, and a lithium iron phosphate precursor which is a product of the technical improvement is prepared, and then after a lithium source is added, liFePO4 which is the same as the lithium iron phosphate precursor (Li 3Fe2 (PO 4) 3 and is not less than 99.9%), the lithium iron phosphate precursor is regenerated after the lithium iron phosphate is added, and the lithium iron phosphate precursor is regenerated by high temperature heat treatment under the protection of nitrogen, and is reduced into waste LiFePO4/C, so as LiFePO4 (PO 4) phosphate which is regenerated.
8. The method for recycling and treating the NMP liquid waste according to claim 3, wherein the two-stage condensation technology is a two-stage condensation recycling device system: a substance has different saturated vapor pressures at different temperatures and pressures, when the vapor pressure of the substance reaches the corresponding saturated vapor pressure at a certain temperature, the substance starts to condense, the temperature is called as the dew point temperature of the substance, only if the system temperature is lower than the dew point temperature, the vaporous substance can be condensed from the vapor phase, the condensation method is that the volatile organic compounds have different saturated vapor pressures at different temperatures and pressures, the system temperature is reduced or the system pressure is increased, the substance is converted from the vapor state into the liquid state and is separated from the vapor phase, NMP waste gas in a vacuum drier is cooled to about 40 ℃ through a two-stage condenser, most of NMP is recovered by condensation, a small amount of uncondensed gas enters a vacuum system through the trap, the front end of a vacuum pipeline is provided with a vacuum tail gas trap, the uncondensed vapor is condensed into the liquid phase and flows into a collecting tank, the front end of a liquid tank vacuum pump is provided with a large-volume vacuum buffer tank, and the tail gas is easy to diffuse due to vacuumize, so that the vacuum pipeline is refrigerated, and part of the vacuum tail gas is condensed and flows into the vacuum buffer tank and is periodically discharged as the vacuum liquid.
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