CN116573735A - Recovery treatment process and device for lithium hexafluorophosphate production wastewater - Google Patents
Recovery treatment process and device for lithium hexafluorophosphate production wastewater Download PDFInfo
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- 239000002351 wastewater Substances 0.000 title claims abstract description 121
- 238000000034 method Methods 0.000 title claims abstract description 33
- -1 lithium hexafluorophosphate Chemical compound 0.000 title claims abstract description 26
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 24
- 238000011084 recovery Methods 0.000 title claims abstract description 18
- FAPWRFPIFSIZLT-UHFFFAOYSA-M Sodium chloride Chemical compound [Na+].[Cl-] FAPWRFPIFSIZLT-UHFFFAOYSA-M 0.000 claims abstract description 68
- OYPRJOBELJOOCE-UHFFFAOYSA-N Calcium Chemical compound [Ca] OYPRJOBELJOOCE-UHFFFAOYSA-N 0.000 claims abstract description 46
- 239000011575 calcium Substances 0.000 claims abstract description 46
- 229910052791 calcium Inorganic materials 0.000 claims abstract description 46
- 229910052710 silicon Inorganic materials 0.000 claims abstract description 42
- 239000010703 silicon Substances 0.000 claims abstract description 42
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 claims abstract description 41
- 239000006228 supernatant Substances 0.000 claims abstract description 39
- 229910052731 fluorine Inorganic materials 0.000 claims abstract description 34
- 239000011737 fluorine Substances 0.000 claims abstract description 34
- 239000011780 sodium chloride Substances 0.000 claims abstract description 34
- 238000006115 defluorination reaction Methods 0.000 claims abstract description 29
- 239000000203 mixture Substances 0.000 claims abstract description 28
- 239000011574 phosphorus Substances 0.000 claims abstract description 28
- 229910052698 phosphorus Inorganic materials 0.000 claims abstract description 28
- 239000002244 precipitate Substances 0.000 claims abstract description 25
- 238000002156 mixing Methods 0.000 claims abstract description 13
- 239000000706 filtrate Substances 0.000 claims description 43
- 238000001914 filtration Methods 0.000 claims description 42
- 239000002904 solvent Substances 0.000 claims description 34
- 238000009287 sand filtration Methods 0.000 claims description 27
- UXVMQQNJUSDDNG-UHFFFAOYSA-L Calcium chloride Chemical compound [Cl-].[Cl-].[Ca+2] UXVMQQNJUSDDNG-UHFFFAOYSA-L 0.000 claims description 20
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 20
- YCKRFDGAMUMZLT-UHFFFAOYSA-N Fluorine atom Chemical compound [F] YCKRFDGAMUMZLT-UHFFFAOYSA-N 0.000 claims description 19
- 239000001110 calcium chloride Substances 0.000 claims description 17
- 229910001628 calcium chloride Inorganic materials 0.000 claims description 17
- 230000001105 regulatory effect Effects 0.000 claims description 15
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 claims description 14
- 235000008733 Citrus aurantifolia Nutrition 0.000 claims description 9
- 235000011941 Tilia x europaea Nutrition 0.000 claims description 9
- 239000000839 emulsion Substances 0.000 claims description 9
- 239000004571 lime Substances 0.000 claims description 9
- 239000010802 sludge Substances 0.000 claims description 9
- 239000003513 alkali Substances 0.000 claims description 8
- 238000004064 recycling Methods 0.000 claims description 7
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 claims description 6
- 239000007800 oxidant agent Substances 0.000 claims description 5
- 230000007935 neutral effect Effects 0.000 claims description 4
- 230000003647 oxidation Effects 0.000 claims description 4
- 238000007254 oxidation reaction Methods 0.000 claims description 4
- 238000001556 precipitation Methods 0.000 claims description 4
- 239000005708 Sodium hypochlorite Substances 0.000 claims description 3
- 239000012530 fluid Substances 0.000 claims description 3
- SUKJFIGYRHOWBL-UHFFFAOYSA-N sodium hypochlorite Chemical compound [Na+].Cl[O-] SUKJFIGYRHOWBL-UHFFFAOYSA-N 0.000 claims description 3
- 230000008901 benefit Effects 0.000 abstract description 10
- 239000002699 waste material Substances 0.000 abstract description 10
- DGAQECJNVWCQMB-PUAWFVPOSA-M Ilexoside XXIX Chemical compound C[C@@H]1CC[C@@]2(CC[C@@]3(C(=CC[C@H]4[C@]3(CC[C@@H]5[C@@]4(CC[C@@H](C5(C)C)OS(=O)(=O)[O-])C)C)[C@@H]2[C@]1(C)O)C)C(=O)O[C@H]6[C@@H]([C@H]([C@@H]([C@H](O6)CO)O)O)O.[Na+] DGAQECJNVWCQMB-PUAWFVPOSA-M 0.000 abstract description 7
- 239000011734 sodium Substances 0.000 abstract description 7
- 229910052708 sodium Inorganic materials 0.000 abstract description 7
- 238000004065 wastewater treatment Methods 0.000 abstract description 7
- PXGOKWXKJXAPGV-UHFFFAOYSA-N Fluorine Chemical compound FF PXGOKWXKJXAPGV-UHFFFAOYSA-N 0.000 abstract 1
- PQXKHYXIUOZZFA-UHFFFAOYSA-M lithium fluoride Chemical compound [Li+].[F-] PQXKHYXIUOZZFA-UHFFFAOYSA-M 0.000 description 22
- PUZPDOWCWNUUKD-UHFFFAOYSA-M sodium fluoride Chemical compound [F-].[Na+] PUZPDOWCWNUUKD-UHFFFAOYSA-M 0.000 description 14
- KRHYYFGTRYWZRS-UHFFFAOYSA-N Fluorane Chemical compound F KRHYYFGTRYWZRS-UHFFFAOYSA-N 0.000 description 10
- 230000000052 comparative effect Effects 0.000 description 9
- 230000000694 effects Effects 0.000 description 8
- 239000011775 sodium fluoride Substances 0.000 description 7
- 235000013024 sodium fluoride Nutrition 0.000 description 7
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 description 5
- 229910052744 lithium Inorganic materials 0.000 description 5
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 4
- 238000000926 separation method Methods 0.000 description 4
- 150000001875 compounds Chemical class 0.000 description 3
- 239000003792 electrolyte Substances 0.000 description 3
- 239000008394 flocculating agent Substances 0.000 description 3
- 239000000126 substance Substances 0.000 description 3
- HBBGRARXTFLTSG-UHFFFAOYSA-N Lithium ion Chemical compound [Li+] HBBGRARXTFLTSG-UHFFFAOYSA-N 0.000 description 2
- NBIIXXVUZAFLBC-UHFFFAOYSA-N Phosphoric acid Chemical compound OP(O)(O)=O NBIIXXVUZAFLBC-UHFFFAOYSA-N 0.000 description 2
- WUKWITHWXAAZEY-UHFFFAOYSA-L calcium difluoride Chemical compound [F-].[F-].[Ca+2] WUKWITHWXAAZEY-UHFFFAOYSA-L 0.000 description 2
- 229910001634 calcium fluoride Inorganic materials 0.000 description 2
- 239000001506 calcium phosphate Substances 0.000 description 2
- 229910000389 calcium phosphate Inorganic materials 0.000 description 2
- 235000011010 calcium phosphates Nutrition 0.000 description 2
- 238000006243 chemical reaction Methods 0.000 description 2
- 229910001416 lithium ion Inorganic materials 0.000 description 2
- 239000005416 organic matter Substances 0.000 description 2
- 230000001590 oxidative effect Effects 0.000 description 2
- 238000002360 preparation method Methods 0.000 description 2
- 239000013049 sediment Substances 0.000 description 2
- 239000000377 silicon dioxide Substances 0.000 description 2
- 235000012239 silicon dioxide Nutrition 0.000 description 2
- QORWJWZARLRLPR-UHFFFAOYSA-H tricalcium bis(phosphate) Chemical compound [Ca+2].[Ca+2].[Ca+2].[O-]P([O-])([O-])=O.[O-]P([O-])([O-])=O QORWJWZARLRLPR-UHFFFAOYSA-H 0.000 description 2
- 229910013872 LiPF Inorganic materials 0.000 description 1
- 101150058243 Lipf gene Proteins 0.000 description 1
- 229910004298 SiO 2 Inorganic materials 0.000 description 1
- 239000002253 acid Substances 0.000 description 1
- 230000002378 acidificating effect Effects 0.000 description 1
- 229910000147 aluminium phosphate Inorganic materials 0.000 description 1
- 238000011001 backwashing Methods 0.000 description 1
- 230000005540 biological transmission Effects 0.000 description 1
- 239000006227 byproduct Substances 0.000 description 1
- 230000003197 catalytic effect Effects 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 238000012851 eutrophication Methods 0.000 description 1
- 239000000945 filler Substances 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 238000009776 industrial production Methods 0.000 description 1
- 150000002500 ions Chemical class 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 238000006386 neutralization reaction Methods 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 239000010865 sewage Substances 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- 239000002352 surface water Substances 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/52—Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities
- C02F1/5281—Installations for water purification using chemical agents
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
- C01B33/00—Silicon; Compounds thereof
- C01B33/08—Compounds containing halogen
- C01B33/10—Compounds containing silicon, fluorine, and other elements
- C01B33/103—Fluosilicic acid; Salts thereof
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/58—Treatment of water, waste water, or sewage by removing specified dissolved compounds
- C02F1/583—Treatment of water, waste water, or sewage by removing specified dissolved compounds by removing fluoride or fluorine compounds
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/66—Treatment of water, waste water, or sewage by neutralisation; pH adjustment
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F2103/00—Nature of the water, waste water, sewage or sludge to be treated
- C02F2103/34—Nature of the water, waste water, sewage or sludge to be treated from industrial activities not provided for in groups C02F2103/12 - C02F2103/32
-
- 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
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/10—Energy storage using batteries
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- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Life Sciences & Earth Sciences (AREA)
- Hydrology & Water Resources (AREA)
- Engineering & Computer Science (AREA)
- Environmental & Geological Engineering (AREA)
- Water Supply & Treatment (AREA)
- Chemical Kinetics & Catalysis (AREA)
- General Chemical & Material Sciences (AREA)
- Inorganic Chemistry (AREA)
- Removal Of Specific Substances (AREA)
Abstract
The application relates to a recovery treatment process of lithium hexafluorophosphate production wastewater, which comprises the following steps: s1, collecting high-fluorine high-phosphorus wastewater, and performing dephosphorization treatment to obtain dephosphorization wastewater; s2, mixing the dephosphorization wastewater and LiF wastewater, and adjusting to be alkaline to form alkaline wastewater; s3, preliminary defluorination is carried out on the alkaline wastewater by adopting a calcium method, and a precipitate and a supernatant are formed; s4, adding a mixture of silicon and sodium chloride into the supernatant to perform deep defluorination, and collecting and recovering the precipitate. According to the recovery treatment process for the lithium hexafluorophosphate production wastewater, provided by the application, the fluorine is removed by adopting a mode of combining silicon and a calcium method, so that the generation of micro-waste such as CaF or NaF can be reduced, sodium fluosilicate with economic value can be produced, wastewater treatment is realized, and considerable economic benefit is realized.
Description
Technical Field
The application relates to the technical field of sewage treatment, in particular to a recovery treatment process and a recovery treatment device for lithium hexafluorophosphate production wastewater.
Background
In recent years, with the popularization of new energy industries, the lithium battery industry required by new energy automobiles is also rapidly developed. The lithium battery electrolyte is used as one of four materials of a lithium battery, is a carrier for ion transmission in the lithium battery, and plays a role in conducting lithium ions between the anode and the cathode. Lithium hexafluorophosphate (LiPF) 6 ) The electrolyte has the advantages of good ionic conductivity, good electrochemical stability, safety, environmental protection and the like, and is the lithium ion electrolyte which is most widely used at present. In the production process of lithium hexafluorophosphate, byproducts-containing lithium fluoride, high-fluorine high-phosphorus wastewater and other substances which are difficult to remove are generated, and if untreated, the untreated substances are discharged into the environment, the surface water quality is affected, for example, the water body eutrophication, red tide and other serious pollution are caused.
CN110921899a provides a process and apparatus for treating wastewater of lithium hexafluorophosphate and lithium hypofluorophosphate compounds, which comprises: s1, sequentially adding alkali, a calcium-containing compound and a flocculating agent into wastewater, and separating precipitate; s2, adding acid into the wastewater, and enabling the wastewater to pass through fixed bed catalytic filler; s3, adding alkali into the wastewater, and heating the wastewater; s4, adding a dephosphorizing agent and a flocculating agent into the wastewater. The method adopts the principle that alkali is utilized for neutralization to generate CaF or NaF and other micro waste, and then the subsequent separation operation is carried out.
It has the following problems: caF or NaF is waste, the cost of subsequent separation treatment is high and can not be recycled, and after the waste is treated by adopting a calcium method, the fluorine content in the solution accords with the emission standard and can not pollute the environment any more, but the cost of subsequent separation treatment is high, so that the overall production benefit is influenced.
Disclosure of Invention
The application aims to solve the problems of higher subsequent separation treatment cost and influence on the overall production benefit in the prior art, and provides a recovery treatment process for lithium hexafluorophosphate production wastewater.
The application adopts the technical scheme that: the recovery treatment process of the lithium hexafluorophosphate production wastewater comprises the following steps:
s1, collecting high-fluorine high-phosphorus wastewater, and performing dephosphorization treatment to obtain dephosphorization wastewater;
s2, mixing the dephosphorization wastewater and LiF wastewater, and adjusting to be alkaline to form alkaline wastewater;
s3, preliminary defluorination is carried out on the alkaline wastewater by adopting a calcium method, and a precipitate and a supernatant are formed;
s4, adding a mixture of silicon and sodium chloride into the supernatant to perform deep defluorination, and collecting and recovering the precipitate.
The lithium hexafluorophosphate wastewater treatment has the difficulty of thoroughly removing fluorine and phosphorus, alkali, a calcium-containing compound and a flocculating agent are sequentially added into the wastewater in the prior art, and the wastewater is neutralized by the alkali to generate micro waste such as calcium phosphate, calcium fluoride or sodium fluoride, and then the micro waste is subjected to subsequent treatment. The inventors have unexpectedly found that hydrofluoric acid reacts with silicon to recover fluorine.
Further, the step S1 specifically includes:
s11, collecting the high-fluorine high-phosphorus wastewater to a collecting tank;
s12, adding calcium chloride into the collection tank to generate phosphorus-containing sludge;
and S13, filtering to obtain phosphorus removal wastewater, and introducing the wastewater into a fluorine removal regulating tank.
Further, the following steps are also present between step S11 and step S12:
s11a, adding hydrochloric acid and sodium hypochlorite into a collection tank for oxidation;
s11b, adding alkali liquor to make the solution in the collecting tank alkaline.
Further, in step S13, the filtering mode is sand filtration, the supernatant fluid after precipitation enters a sand filtration filter, and the sand filtration filter is backwashed by utilizing water produced by the sand filtration periodically, and the concentrated water produced by the backwashed and the effluent water after the sand filtration enter a defluorination regulating tank as dephosphorization wastewater.
Further, the step S2 specifically includes:
s21, introducing the dephosphorization wastewater and LiF wastewater into a defluorination regulating tank for mixing,
s22, adding lime emulsion, and adjusting to alkalescence.
Further, the step S3 specifically includes:
s31, adding a calcium-containing solvent into the alkaline wastewater, filtering, taking filtrate,
s32, adding the calcium-containing solvent into the filtrate again, filtering, and taking the secondary filtrate as supernatant.
Further, the calcium-containing solvent is calcium chloride solution, PAC or PAM.
Further, the step S4 specifically includes:
s41, adding a mixture of silicon and sodium chloride into the supernatant;
s42, adjusting the supernatant to be neutral to obtain a treatment solution, adding PAC and PAM, and filtering;
s43, repeating the step S42 to enable the filtrate to meet the discharge standard;
s44, collecting and recycling the precipitate.
Further, step S43 includes the steps of:
step S431, repeating step S42 to reduce the fluorine content to 1PPM;
in step S432, a strong oxidizer is added to oxidize the organic matters so that the filtrate meets the emission standard.
Further, in step S42, the filtering mode is sand filtration, and the sand filtration filter is backwashed by the produced water of the sand filtration periodically, and the concentrated water produced by the backwashed is mixed with the effluent water after the sand filtration.
According to the recovery treatment process for the lithium hexafluorophosphate production wastewater, provided by the application, the fluorine is removed by adopting a mode of combining silicon and a calcium method, so that the generation of micro-waste such as CaF or NaF can be reduced, sodium fluosilicate with economic value can be produced, wastewater treatment is realized, and considerable economic benefit is realized.
The foregoing description is only an overview of the present application, and is intended to provide a better understanding of the present application, as it is embodied in the following description, with reference to the preferred embodiments of the present application and the accompanying drawings. Specific embodiments of the present application are given in detail by the following examples and the accompanying drawings.
Drawings
The accompanying drawings, which are included to provide a further understanding of the application and are incorporated in and constitute a part of this specification, illustrate embodiments of the application and together with the description serve to explain the application and do not constitute a limitation on the application. In the drawings:
fig. 1 is a flow chart of a recovery treatment process of lithium hexafluorophosphate production wastewater.
Detailed Description
The principles and features of the present application are described below with reference to the drawings, the examples are illustrated for the purpose of illustrating the application and are not to be construed as limiting the scope of the application. The application is more particularly described by way of example in the following paragraphs with reference to the drawings. Advantages and features of the application will become more apparent from the following description and from the claims. It should be noted that the drawings are in a very simplified form and are all to a non-precise scale, merely for convenience and clarity in aiding in the description of embodiments of the application.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein in the description of the application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The term "or/and" as used herein includes any and all combinations of one or more of the associated listed items.
The recovery treatment process of the lithium hexafluorophosphate production wastewater provided by the application is described below with reference to the accompanying drawings:
referring to fig. 1, the process for recycling and treating lithium hexafluorophosphate production wastewater provided by the application comprises the following steps:
s1, collecting high-fluorine high-phosphorus wastewater, and performing dephosphorization treatment to obtain dephosphorization wastewater;
s2, mixing the dephosphorization wastewater and LiF wastewater, and adjusting to be alkaline to form alkaline wastewater;
s3, preliminary defluorination is carried out on the alkaline wastewater by adopting a calcium method, and a precipitate and a supernatant are formed;
s4, adding a mixture of silicon and sodium chloride into the supernatant to perform deep defluorination, and collecting and recovering the precipitate.
The application adopts the mode of combining silicon and a calcium method to remove fluorine, can reduce the generation of micro waste such as CaF or NaF, and can produce sodium fluosilicate with economic value, thereby realizing wastewater treatment and considerable economic benefit.
Preferably, step S1 specifically includes:
s11, collecting the high-fluorine high-phosphorus wastewater to a collecting tank;
s12, adding calcium chloride into the collection tank to generate phosphorus-containing sludge;
and S13, filtering to obtain phosphorus removal wastewater, and introducing the wastewater into a fluorine removal regulating tank.
The calcium chloride reacts with the phosphoric acid solution to produce precipitates of calcium phosphate and the like, thereby realizing the dephosphorization treatment.
Preferably, between step S11 and step S12 there is also the following step:
s11a, adding hydrochloric acid and sodium hypochlorite into a collection tank for oxidation;
s11b, adding alkali liquor to make the solution in the collecting tank alkaline.
The purpose of the steps is to firstly oxidize substances in the solution, and then to prepare the solution in the collecting tank to be alkaline so as to avoid the generation of sediment blocked by an acidic environment after the oxidation is finished and to facilitate the generation of sediment in the subsequent steps.
In step S13, the filtering mode is sand filtration, the supernatant fluid after precipitation enters the sand filtration filter, and the sand filtration filter is backwashed by the produced water of the sand filtration at regular intervals, and the concentrated water produced by the back washing and the effluent water after the sand filtration enter a fluorine removal regulating tank as phosphorus removal wastewater.
Preferably, step S2 specifically includes:
s21, introducing the dephosphorization wastewater and LiF wastewater into a defluorination regulating tank for mixing,
s22, adding lime emulsion, and adjusting to alkalescence.
Preferably, step S3 specifically includes:
s31, adding a calcium-containing solvent into the alkaline wastewater, filtering, taking filtrate,
s32, adding the calcium-containing solvent into the filtrate again, filtering, and taking the secondary filtrate as supernatant.
And step S3, adopting a two-stage calcium method to carry out secondary treatment on fluorine in the wastewater, and reducing the fluorine content in the wastewater to below 15mg/L as much as possible.
In this embodiment, the calcium-containing solvent comprises a calcium chloride solution, PAC, PAM. Calcium chloride reacts with fluoride ions in wastewater to generate precipitate, and PAC and PAM are added to accelerate natural precipitation.
Preferably, step S4 specifically includes:
s41, adding a mixture of silicon and sodium chloride into the supernatant;
s42, adjusting the supernatant to be neutral to obtain a treatment solution, adding PAC and PAM, and filtering;
s43, repeating the step S42 to enable the filtrate to meet the discharge standard;
s44, collecting and recycling the precipitate.
Silicon reacts with hydrofluoric acid as follows:
6HF+Si＝H 2 SiF 6 +2H 2 . Sodium chloride is also added, so that sodium fluosilicate is generated; sodium fluosilicate is an important raw material for industrial production, the market price of the sodium fluosilicate is 3000-4000 tons, the subsequent sales treatment can be carried out, and considerable economic benefit is realized while the wastewater treatment is realized; sodium fluoride and calcium fluoride generated by the conventional treatment means are micro-waste, and the subsequent treatment still needs to pay cost; in contrast, the application can realize wastewater treatment and considerable economic benefit compared with the prior art.
Preferably, in step S42, the filtering mode is sand filtration, and the sand filtration filter is backwashed by the produced water of the sand filtration periodically, and the concentrated water produced by the backwashed is mixed with the effluent water after the sand filtration.
Preferably, step S43 comprises the steps of:
step S431, repeating step S42 to reduce the fluorine content to 1PPM;
in step S432, a strong oxidizer is added to oxidize the organic matters so that the filtrate meets the emission standard.
Preferably, the strong oxidizer in step S432 is H 2 O 2 。H 2 O 2 Oxidizing the organic matter, and oxidizing silicon to form silicon dioxide, wherein the silicon dioxide can react with hydrofluoric acid, 6HF+SiO 2 ＝H 2 SiF 6 +2H 2 O. The reaction rate is faster than that of silicon and hydrofluoric acid, H 2 O 2 The reaction of silicon with hydrofluoric acid is substantially accelerated.
In order for the filtrate to meet emission standards, it is necessary to oxidize and remove the organic matter contained therein with an oxidizing agent prior to emission.
The whole flow is as follows: firstly, collecting high-fluorine high-phosphorus wastewater into a collecting tank, adding calcium chloride into the collecting tank to generate phosphorus-containing sludge, filtering to obtain phosphorus-removing wastewater, and introducing the phosphorus-removing wastewater into a fluorine-removing regulating tank; then introducing the dephosphorization wastewater and LiF wastewater into a defluorination adjusting tank for mixing, and adding lime emulsion into the defluorination adjusting tank for adjusting to alkalescence; then adding a calcium-containing solvent into the alkaline wastewater, filtering, taking filtrate, adding the calcium-containing solvent into the filtrate again, filtering, and taking secondary filtrate as supernatant; and finally, adding a mixture of silicon and sodium chloride into the supernatant, adjusting the supernatant to be neutral to obtain a treatment liquid, adding PAC and PAM, filtering, repeating the steps to ensure that the filtrate meets the emission standard, and collecting and recovering the precipitate.
In this embodiment, the preparation process of the mixture of silicon and sodium chloride is as follows, in parts by weight: firstly, 1 part of silicon is ground to 200-300 meshes, 2-3 parts of sodium chloride is ground to 150-200 meshes, and then the silicon and the sodium chloride are uniformly mixed to obtain a mixture of the silicon and the sodium chloride. One part of the mixture of silicon and sodium chloride is added per liter of wastewater.
In this embodiment, the preparation process of the above one part of the calcium-containing solvent is as follows, in parts by weight: dissolving 250-350 g of calcium chloride in water, adding PAC and PAM into the solution, wherein the addition amount of PAC is 200-300mg/L, and the addition amount of PAM is 3-10mg/L, so as to obtain the calcium-containing solvent.
Example 1
Firstly, collecting high-fluorine high-phosphorus wastewater into a collecting tank, adding calcium chloride into the collecting tank to generate phosphorus-containing sludge, filtering to obtain phosphorus-removing wastewater, and introducing the phosphorus-removing wastewater into a fluorine-removing regulating tank; then introducing the dephosphorization wastewater and LiF wastewater into a defluorination adjusting tank for mixing, and adding lime emulsion into the defluorination adjusting tank for adjusting to alkalescence; then adding a calcium-containing solvent into the alkaline wastewater, and adding one part of the calcium-containing solvent into one liter of the alkaline wastewater, wherein one part of the calcium-containing solvent contains 250g of calcium chloride, 200mg/L of PAC and 3mg/L of PAM; filtering, collecting filtrate, adding calcium-containing solvent into the filtrate again, filtering, and collecting secondary filtrate as supernatant; finally adding a mixture of silicon and sodium chloride into the supernatant, and adding one part of the mixture of silicon and sodium chloride into one liter of supernatant, wherein one part of the mixture of silicon and sodium chloride comprises 1 part of silicon ground to 200 meshes and 2 parts of sodium chloride ground to 150 meshes; adjusting the supernatant to neutrality to obtain a treatment solution, adding PAC and PAM, filtering, repeating the steps to make the filtrate meet the discharge standard, and collecting and recovering the precipitate. The content of F in the filtrate was determined and the precipitate was examined.
Example 2
Firstly, collecting high-fluorine high-phosphorus wastewater into a collecting tank, adding calcium chloride into the collecting tank to generate phosphorus-containing sludge, filtering to obtain phosphorus-removing wastewater, and introducing the phosphorus-removing wastewater into a fluorine-removing regulating tank; then introducing the dephosphorization wastewater and LiF wastewater into a defluorination adjusting tank for mixing, and adding lime emulsion into the defluorination adjusting tank for adjusting to alkalescence; then adding a calcium-containing solvent into the alkaline wastewater, and adding one part of the calcium-containing solvent into one liter of the alkaline wastewater, wherein one part of the calcium-containing solvent contains 250g of calcium chloride, 200mg/L of PAC and 3mg/L of PAM; filtering, collecting filtrate, adding calcium-containing solvent into the filtrate again, filtering, and collecting secondary filtrate as supernatant; finally, adding a mixture of silicon and sodium chloride into the supernatant, and adding one part of the mixture of silicon and sodium chloride into one liter of supernatant. 1 part of silicon ground to 300 meshes and 3 parts of sodium chloride ground to 200 meshes in a mixture of silicon and sodium chloride; adjusting the supernatant to neutrality to obtain a treatment solution, adding PAC and PAM, filtering, repeating the steps to make the filtrate meet the discharge standard, and collecting and recovering the precipitate. The content of F in the filtrate was determined and the precipitate was examined.
Example 3
Firstly, collecting high-fluorine high-phosphorus wastewater into a collecting tank, adding calcium chloride into the collecting tank to generate phosphorus-containing sludge, filtering to obtain phosphorus-removing wastewater, and introducing the phosphorus-removing wastewater into a fluorine-removing regulating tank; then introducing the dephosphorization wastewater and LiF wastewater into a defluorination adjusting tank for mixing, and adding lime emulsion into the defluorination adjusting tank for adjusting to alkalescence; then adding a calcium-containing solvent into the alkaline wastewater, and adding one part of the calcium-containing solvent into one liter of the alkaline wastewater, wherein one part of the calcium-containing solvent contains 350g of calcium chloride, 300mg/L of PAC and 10mg/L of PAM; filtering, collecting filtrate, adding calcium-containing solvent into the filtrate again, filtering, and collecting secondary filtrate as supernatant; finally, adding a mixture of silicon and sodium chloride into the supernatant, and adding one part of the mixture of silicon and sodium chloride into one liter of supernatant. The mixture of one part of silicon and sodium chloride comprises 1 part of silicon ground to 200 meshes and 2 parts of sodium chloride ground to 150 meshes; adjusting the supernatant to neutrality to obtain a treatment solution, adding PAC and PAM, filtering, repeating the steps to make the filtrate meet the discharge standard, and collecting and recovering the precipitate. The content of F in the filtrate was determined and the precipitate was examined.
Comparative example 1
Firstly, collecting high-fluorine high-phosphorus wastewater into a collecting tank, adding calcium chloride into the collecting tank to generate phosphorus-containing sludge, filtering to obtain phosphorus-removing wastewater, and introducing the phosphorus-removing wastewater into a fluorine-removing regulating tank; then introducing the dephosphorization wastewater and LiF wastewater into a defluorination adjusting tank for mixing, and adding lime emulsion into the defluorination adjusting tank for adjusting to alkalescence; then adding a calcium-containing solvent into the alkaline wastewater, and adding one part of the calcium-containing solvent into one liter of the alkaline wastewater, wherein one part of the calcium-containing solvent contains 250g of calcium chloride, 200mg/L of PAC and 3mg/L of PAM; filtering, collecting filtrate, adding calcium-containing solvent into the filtrate again, filtering, and collecting secondary filtrate as supernatant; adjusting the supernatant to neutrality to obtain a treatment solution, filtering, and collecting and recovering precipitate. The content of F in the filtrate was determined and the precipitate was examined.
Comparative example 2
Firstly, collecting high-fluorine high-phosphorus wastewater into a collecting tank, adding calcium chloride into the collecting tank to generate phosphorus-containing sludge, filtering to obtain phosphorus-removing wastewater, and introducing the phosphorus-removing wastewater into a fluorine-removing regulating tank; then introducing the dephosphorization wastewater and LiF wastewater into a defluorination adjusting tank for mixing, and adding lime emulsion into the defluorination adjusting tank for adjusting to alkalescence; then adding a calcium-containing solvent into the alkaline wastewater, and adding one part of the calcium-containing solvent into one liter of the alkaline wastewater, wherein one part of the calcium-containing solvent contains 350g of calcium chloride, 300mg/L of PAC and 10mg/L of PAM; filtering, collecting filtrate, adding calcium-containing solvent into the filtrate again, filtering, and collecting secondary filtrate as supernatant; adjusting the supernatant to neutrality to obtain a treatment solution, filtering, and collecting and recovering precipitate. The content of F in the filtrate was determined and the precipitate was examined.
The results of examples 1, 2, 3 and comparative examples 1, 2 are as follows:
comparing example 1 with example 2, example 2 adds a mixture of silicon and sodium chloride compared with example 1, and example 2 has better defluorination effect, which indicates that the mixture of silicon and sodium chloride does have a certain defluorination effect;
comparing example 2 with example 3, example 2 increases the mixture of silicon and sodium chloride and reduces the amount of the calcium-containing solvent compared with example 3, but the defluorination effect is closer, which indicates that the mixture of silicon and sodium chloride does have a certain defluorination effect;
comparative example 1 is compared with example 2, and the mixture of silicon and sodium chloride is not added in comparative example 1, so that the fluorine removal effect of comparative example 1 is weaker than that of example 2, and the mixture of silicon and sodium chloride is proved to have certain fluorine removal effect;
comparative example 2 was compared with example 3, and the mixture of silicon and sodium chloride was not added in comparative example 2, and the fluorine removal effect of comparative example 2 was weaker than that of example 3, and it was also confirmed that the mixture of silicon and sodium chloride did indeed exert a certain fluorine removal effect.
The application adopts the mode of combining silicon and a calcium method to remove fluorine, can reduce the generation of micro waste such as CaF or NaF, and can produce sodium fluosilicate with economic value, thereby realizing wastewater treatment and considerable economic benefit.
The present application is not limited to the above-mentioned embodiments, and any changes or substitutions that can be easily understood by those skilled in the art within the technical scope of the present application are intended to be included in the scope of the present application.
Claims (10)
1. The recovery treatment process of the lithium hexafluorophosphate production wastewater is characterized by comprising the following steps of:
s1, collecting high-fluorine high-phosphorus wastewater, and performing dephosphorization treatment to obtain dephosphorization wastewater;
s2, mixing the dephosphorization wastewater and LiF wastewater, and adjusting to be alkaline to form alkaline wastewater;
s3, preliminary defluorination is carried out on the alkaline wastewater by adopting a calcium method, and a precipitate and a supernatant are formed;
s4, adding a mixture of silicon and sodium chloride into the supernatant to perform deep defluorination, and collecting and recovering the precipitate.
2. The lithium hexafluorophosphate production wastewater recovery treatment process according to claim 1, wherein step S1 specifically comprises:
s11, collecting the high-fluorine high-phosphorus wastewater to a collecting tank;
s12, adding calcium chloride into the collection tank to generate phosphorus-containing sludge;
and S13, filtering to obtain phosphorus removal wastewater, and introducing the wastewater into a fluorine removal regulating tank.
3. The lithium hexafluorophosphate production wastewater recovery treatment process according to claim 2, wherein the following steps are further present between step S11 and step S12:
s11a, adding hydrochloric acid and sodium hypochlorite into a collection tank for oxidation;
s11b, adding alkali liquor to make the solution in the collecting tank alkaline.
4. The process for recycling lithium hexafluorophosphate production wastewater according to claim 2, wherein in step S13, the filtering mode is sand filtration, the supernatant fluid after precipitation enters a sand filtration filter, the sand filtration filter is backwashed by the produced water of the sand filtration at regular intervals, and the concentrated water produced by the backwashed and the effluent water after the sand filtration enter a defluorination regulating tank as dephosphorization wastewater.
5. The lithium hexafluorophosphate production wastewater recovery treatment process according to claim 1, wherein step S2 specifically comprises:
s21, introducing the dephosphorization wastewater and LiF wastewater into a defluorination regulating tank for mixing,
s22, adding lime emulsion, and adjusting to alkalescence.
6. The lithium hexafluorophosphate production wastewater recovery treatment process according to claim 1, wherein step S3 specifically comprises:
s31, adding a calcium-containing solvent into the alkaline wastewater, filtering, taking filtrate,
s32, adding the calcium-containing solvent into the filtrate again, filtering, and taking the secondary filtrate as supernatant.
7. The process for recycling lithium hexafluorophosphate production wastewater according to claim 6, wherein the calcium-containing solvent comprises calcium chloride solution, PAC and PAM.
8. The lithium hexafluorophosphate production wastewater recovery treatment process according to claim 1, wherein step S4 specifically comprises:
s41, adding a mixture of silicon and sodium chloride into the supernatant;
s42, adjusting the supernatant to be neutral to obtain a treatment solution, adding PAC and PAM, and filtering;
s43, repeating the step S42 to enable the filtrate to meet the discharge standard;
s44, collecting and recycling the precipitate.
9. The lithium hexafluorophosphate production wastewater recovery treatment process according to claim 8, wherein step S43 comprises the steps of:
step S431, repeating step S42 to reduce the fluorine content to 1PPM;
in step S432, a strong oxidizer is added to make the filtrate meet the emission standard.
10. The process for recycling lithium hexafluorophosphate production wastewater according to claim 8, wherein in step S42, the filtration mode is sand filtration, and the sand filtration filter is backwashed by the produced water of the sand filtration periodically, and the concentrated water produced by the backwashed is mixed with the effluent water after the sand filtration.
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