CN113200624A - Defluorination process for washing smelting flue gas wastewater - Google Patents
Defluorination process for washing smelting flue gas wastewater Download PDFInfo
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- 239000002351 wastewater Substances 0.000 title claims abstract description 113
- 238000000034 method Methods 0.000 title claims abstract description 98
- 230000008569 process Effects 0.000 title claims abstract description 98
- 238000006115 defluorination reaction Methods 0.000 title claims abstract description 62
- 238000005406 washing Methods 0.000 title claims abstract description 40
- 238000003723 Smelting Methods 0.000 title claims abstract description 31
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 title claims abstract description 30
- 239000003546 flue gas Substances 0.000 title claims abstract description 30
- 239000011737 fluorine Substances 0.000 claims abstract description 71
- 229910052731 fluorine Inorganic materials 0.000 claims abstract description 71
- 239000007788 liquid Substances 0.000 claims abstract description 63
- 238000006243 chemical reaction Methods 0.000 claims abstract description 53
- 238000006386 neutralization reaction Methods 0.000 claims abstract description 42
- 238000010517 secondary reaction Methods 0.000 claims abstract description 38
- 239000002562 thickening agent Substances 0.000 claims abstract description 28
- DIZPMCHEQGEION-UHFFFAOYSA-H aluminium sulfate (anhydrous) Chemical compound [Al+3].[Al+3].[O-]S([O-])(=O)=O.[O-]S([O-])(=O)=O.[O-]S([O-])(=O)=O DIZPMCHEQGEION-UHFFFAOYSA-H 0.000 claims abstract description 27
- 230000003647 oxidation Effects 0.000 claims abstract description 26
- 238000007254 oxidation reaction Methods 0.000 claims abstract description 26
- 229910000360 iron(III) sulfate Inorganic materials 0.000 claims abstract description 24
- RUTXIHLAWFEWGM-UHFFFAOYSA-H iron(3+) sulfate Chemical compound [Fe+3].[Fe+3].[O-]S([O-])(=O)=O.[O-]S([O-])(=O)=O.[O-]S([O-])(=O)=O RUTXIHLAWFEWGM-UHFFFAOYSA-H 0.000 claims abstract description 23
- AXCZMVOFGPJBDE-UHFFFAOYSA-L calcium dihydroxide Chemical compound [OH-].[OH-].[Ca+2] AXCZMVOFGPJBDE-UHFFFAOYSA-L 0.000 claims abstract description 14
- 239000000920 calcium hydroxide Substances 0.000 claims abstract description 14
- 229910001861 calcium hydroxide Inorganic materials 0.000 claims abstract description 14
- 238000005086 pumping Methods 0.000 claims abstract description 13
- 238000000926 separation method Methods 0.000 claims abstract description 13
- 239000006228 supernatant Substances 0.000 claims abstract description 13
- 239000000243 solution Substances 0.000 claims description 74
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 claims description 72
- 238000003756 stirring Methods 0.000 claims description 56
- -1 aluminum ions Chemical class 0.000 claims description 40
- 239000002131 composite material Substances 0.000 claims description 40
- QTBSBXVTEAMEQO-UHFFFAOYSA-N Acetic acid Chemical compound CC(O)=O QTBSBXVTEAMEQO-UHFFFAOYSA-N 0.000 claims description 36
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 claims description 32
- 229920000881 Modified starch Polymers 0.000 claims description 32
- 239000004368 Modified starch Substances 0.000 claims description 32
- 235000019426 modified starch Nutrition 0.000 claims description 32
- VEXZGXHMUGYJMC-UHFFFAOYSA-M Chloride anion Chemical compound [Cl-] VEXZGXHMUGYJMC-UHFFFAOYSA-M 0.000 claims description 30
- RBTARNINKXHZNM-UHFFFAOYSA-K iron trichloride Chemical compound Cl[Fe](Cl)Cl RBTARNINKXHZNM-UHFFFAOYSA-K 0.000 claims description 30
- 238000002156 mixing Methods 0.000 claims description 28
- 229910021578 Iron(III) chloride Inorganic materials 0.000 claims description 26
- 229940032296 ferric chloride Drugs 0.000 claims description 26
- VSCWAEJMTAWNJL-UHFFFAOYSA-K aluminium trichloride Chemical compound Cl[Al](Cl)Cl VSCWAEJMTAWNJL-UHFFFAOYSA-K 0.000 claims description 24
- 238000010438 heat treatment Methods 0.000 claims description 24
- 238000002360 preparation method Methods 0.000 claims description 21
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 19
- 230000000694 effects Effects 0.000 claims description 17
- KFZMGEQAYNKOFK-UHFFFAOYSA-N Isopropanol Chemical compound CC(C)O KFZMGEQAYNKOFK-UHFFFAOYSA-N 0.000 claims description 16
- 238000001035 drying Methods 0.000 claims description 16
- 239000008394 flocculating agent Substances 0.000 claims description 10
- XEEYBQQBJWHFJM-UHFFFAOYSA-N iron Substances [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims description 10
- 229920002261 Corn starch Polymers 0.000 claims description 8
- 229910052782 aluminium Inorganic materials 0.000 claims description 8
- 239000007864 aqueous solution Substances 0.000 claims description 8
- FOCAUTSVDIKZOP-UHFFFAOYSA-N chloroacetic acid Chemical compound OC(=O)CCl FOCAUTSVDIKZOP-UHFFFAOYSA-N 0.000 claims description 8
- 239000008120 corn starch Substances 0.000 claims description 8
- 229940044631 ferric chloride hexahydrate Drugs 0.000 claims description 8
- 238000001914 filtration Methods 0.000 claims description 8
- 229910052742 iron Inorganic materials 0.000 claims description 8
- NQXWGWZJXJUMQB-UHFFFAOYSA-K iron trichloride hexahydrate Chemical compound O.O.O.O.O.O.[Cl-].Cl[Fe+]Cl NQXWGWZJXJUMQB-UHFFFAOYSA-K 0.000 claims description 8
- 230000007935 neutral effect Effects 0.000 claims description 8
- PXGOKWXKJXAPGV-UHFFFAOYSA-N Fluorine Chemical compound FF PXGOKWXKJXAPGV-UHFFFAOYSA-N 0.000 claims 2
- 239000007789 gas Substances 0.000 claims 2
- YCKRFDGAMUMZLT-UHFFFAOYSA-N Fluorine atom Chemical compound [F] YCKRFDGAMUMZLT-UHFFFAOYSA-N 0.000 abstract description 17
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 abstract description 6
- 230000008901 benefit Effects 0.000 abstract description 5
- 239000003344 environmental pollutant Substances 0.000 abstract description 4
- 231100000719 pollutant Toxicity 0.000 abstract description 4
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 abstract description 3
- 239000010941 cobalt Substances 0.000 abstract description 3
- 229910017052 cobalt Inorganic materials 0.000 abstract description 3
- GUTLYIVDDKVIGB-UHFFFAOYSA-N cobalt atom Chemical compound [Co] GUTLYIVDDKVIGB-UHFFFAOYSA-N 0.000 abstract description 3
- 229910052802 copper Inorganic materials 0.000 abstract description 3
- 239000010949 copper Substances 0.000 abstract description 3
- 230000007613 environmental effect Effects 0.000 abstract description 3
- 229910052759 nickel Inorganic materials 0.000 abstract description 3
- 238000005189 flocculation Methods 0.000 description 24
- 230000016615 flocculation Effects 0.000 description 24
- QAOWNCQODCNURD-UHFFFAOYSA-L Sulfate Chemical compound [O-]S([O-])(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-L 0.000 description 15
- 229920001661 Chitosan Polymers 0.000 description 13
- 239000003463 adsorbent Substances 0.000 description 13
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 9
- 239000011812 mixed powder Substances 0.000 description 8
- 230000009471 action Effects 0.000 description 7
- 239000012530 fluid Substances 0.000 description 7
- 238000001179 sorption measurement Methods 0.000 description 7
- 230000003311 flocculating effect Effects 0.000 description 5
- 239000002994 raw material Substances 0.000 description 5
- 150000003839 salts Chemical class 0.000 description 5
- 238000004062 sedimentation Methods 0.000 description 5
- 230000003213 activating effect Effects 0.000 description 4
- AZDRQVAHHNSJOQ-UHFFFAOYSA-N alumane Chemical class [AlH3] AZDRQVAHHNSJOQ-UHFFFAOYSA-N 0.000 description 4
- CYUOWZRAOZFACA-UHFFFAOYSA-N aluminum iron Chemical compound [Al].[Fe] CYUOWZRAOZFACA-UHFFFAOYSA-N 0.000 description 4
- 239000004927 clay Substances 0.000 description 4
- 238000000227 grinding Methods 0.000 description 4
- 239000004571 lime Substances 0.000 description 4
- 235000011837 pasties Nutrition 0.000 description 4
- 230000036632 reaction speed Effects 0.000 description 4
- 238000007873 sieving Methods 0.000 description 4
- 238000001291 vacuum drying Methods 0.000 description 4
- 235000008733 Citrus aurantifolia Nutrition 0.000 description 3
- 235000011941 Tilia x europaea Nutrition 0.000 description 3
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 3
- 239000000084 colloidal system Substances 0.000 description 3
- 229910052760 oxygen Inorganic materials 0.000 description 3
- 239000001301 oxygen Substances 0.000 description 3
- 239000002244 precipitate Substances 0.000 description 3
- 239000000126 substance Substances 0.000 description 3
- 238000004065 wastewater treatment Methods 0.000 description 3
- KRHYYFGTRYWZRS-UHFFFAOYSA-M Fluoride anion Chemical compound [F-] KRHYYFGTRYWZRS-UHFFFAOYSA-M 0.000 description 2
- 239000003795 chemical substances by application Substances 0.000 description 2
- 238000010276 construction Methods 0.000 description 2
- 229910052602 gypsum Inorganic materials 0.000 description 2
- 239000010440 gypsum Substances 0.000 description 2
- 239000000413 hydrolysate Substances 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 238000000746 purification Methods 0.000 description 2
- 230000001105 regulatory effect Effects 0.000 description 2
- 229910018626 Al(OH) Inorganic materials 0.000 description 1
- DJHGAFSJWGLOIV-UHFFFAOYSA-N Arsenic acid Chemical compound O[As](O)(O)=O DJHGAFSJWGLOIV-UHFFFAOYSA-N 0.000 description 1
- UXVMQQNJUSDDNG-UHFFFAOYSA-L Calcium chloride Chemical compound [Cl-].[Cl-].[Ca+2] UXVMQQNJUSDDNG-UHFFFAOYSA-L 0.000 description 1
- 229940000488 arsenic acid Drugs 0.000 description 1
- GCPXMJHSNVMWNM-UHFFFAOYSA-N arsenous acid Chemical compound O[As](O)O GCPXMJHSNVMWNM-UHFFFAOYSA-N 0.000 description 1
- FBOFDHMZEDHPPP-UHFFFAOYSA-N arsorous acid;iron(3+);oxygen(2-);pentahydrate Chemical compound O.O.O.O.O.[O-2].[Fe+3].O[As](O)O FBOFDHMZEDHPPP-UHFFFAOYSA-N 0.000 description 1
- 239000011575 calcium Substances 0.000 description 1
- 239000001110 calcium chloride Substances 0.000 description 1
- 229910001628 calcium chloride Inorganic materials 0.000 description 1
- WUKWITHWXAAZEY-UHFFFAOYSA-L calcium difluoride Chemical compound [F-].[F-].[Ca+2] WUKWITHWXAAZEY-UHFFFAOYSA-L 0.000 description 1
- 229910001634 calcium fluoride Inorganic materials 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- 150000001768 cations Chemical class 0.000 description 1
- 238000000975 co-precipitation Methods 0.000 description 1
- 239000000470 constituent Substances 0.000 description 1
- 238000007334 copolymerization reaction Methods 0.000 description 1
- 239000003814 drug Substances 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 239000010842 industrial wastewater Substances 0.000 description 1
- 229910052500 inorganic mineral Inorganic materials 0.000 description 1
- BMWMWYBEJWFCJI-UHFFFAOYSA-K iron(3+);trioxido(oxo)-$l^{5}-arsane Chemical compound [Fe+3].[O-][As]([O-])([O-])=O BMWMWYBEJWFCJI-UHFFFAOYSA-K 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 239000011707 mineral Substances 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- 239000002699 waste material Substances 0.000 description 1
Images
Classifications
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- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F9/00—Multistage treatment of water, waste water or sewage
-
- 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
- C02F1/001—Processes for the treatment of water whereby the filtration technique is of importance
-
- 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
- C02F1/28—Treatment of water, waste water, or sewage by sorption
-
- 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
- C02F1/5236—Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities using inorganic agents
-
- 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
- C02F1/54—Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities using organic material
- C02F1/56—Macromolecular 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
- C02F1/00—Treatment of water, waste water, or sewage
- C02F2001/007—Processes including a sedimentation step
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F2101/00—Nature of the contaminant
- C02F2101/10—Inorganic compounds
- C02F2101/103—Arsenic compounds
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F2101/00—Nature of the contaminant
- C02F2101/10—Inorganic compounds
- C02F2101/12—Halogens or halogen-containing compounds
- C02F2101/14—Fluorine or fluorine-containing compounds
-
- 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
- C02F2103/18—Nature of the water, waste water, sewage or sludge to be treated from the purification of gaseous effluents
Abstract
The invention discloses a defluorination process for washing smelting flue gas wastewater, which comprises the following steps: conveying the high-fluorine wastewater treated by the neutralization process from the intermediate tank of the neutralization process to a primary reaction tank, and adding aluminum sulfate; overflowing the liquid in the primary reaction tank into an oxidation tank, and adding polymeric ferric sulfate; overflowing the liquid in the oxidation tank to a secondary reaction tank, and adding calcium hydroxide; and overflowing the liquid in the secondary reaction tank to a thickener for solid-liquid separation, pumping the supernatant of the thickener to a Siene filter after passing through an overflow weir, and overflowing to a treatment station at the tail end of a pit of an adjusting tank to finish the defluorination of the wastewater. The wastewater defluorination process system is put into normal use, the original wastewater is treated by the newly added defluorination process system, the fluorine content in the wastewater is reduced to be within 5mg/L, and the wastewater can meet the discharge standard of industrial pollutants of copper, cobalt and nickel of GB 25467-2010, and the environmental protection benefit of a company is greatly improved.
Description
Technical Field
The invention relates to the technical field of wastewater treatment, in particular to a defluorination process for washing smelting flue gas wastewater.
Background
Along with the development of modern industry, the exploitation and processing of fluorine-containing minerals, the massive construction and production of metal smelting enterprises, the discharge amount of fluorine-containing wastewater is rapidly increased every year, and the fluorine pollution is more and more serious. In the past, due to the limitation of technical and economic conditions, fluorine belongs to a second class of pollutants, fluorine pollution does not draw enough attention, along with the development of national economy, the requirements of people on the environment are more and more strict, and the discharge standard of industrial wastewater is more and more strict along with the more and more severe domestic safety and environmental protection situation.
The main source of the fluorine-containing wastewater is a purification process, wastewater with high fluorine content (the fluorine content is about 1300 mg/L) is generated in the process of washing smelting flue gas in the purification process, the fluorine content in the wastewater can be reduced to about 300mg/L after the wastewater passes through a gypsum process in a wastewater working section, the fluorine content in the wastewater after being treated by a gypsum process and then being treated in a neutralization working section can be reduced to about 20-40 mg/L, and the wastewater still can not meet the discharge standard of industrial pollutants of copper, cobalt and nickel in GB 25467-2010.
Disclosure of Invention
Aiming at the problems, the invention provides a defluorination process for washing smelting flue gas wastewater, which is based on the existing water treatment process equipment and based on the premise of lowest construction cost and no influence on the original water treatment process, improves the medicament adding structure of the existing wastewater treatment neutralization process and the wastewater treatment sequence to achieve the purpose of wastewater defluorination.
The technical scheme adopted by the invention for solving the problems is as follows: a defluorination process for washing smelting flue gas wastewater comprises the following steps:
step S10, conveying the high-fluorine wastewater treated by the neutralization process from the intermediate tank of the neutralization process to a primary reaction tank through a pump, adding aluminum sulfate into the primary reaction tank, and carrying out reaction treatment for 3-6 hours;
step S20, overflowing the liquid in the primary reaction tank into an oxidation tank, adding polymeric ferric sulfate, and fully reacting the polymeric ferric sulfate with the wastewater under the stirring effect;
step S30, overflowing the liquid in the oxidation tank to a secondary reaction tank, adding calcium hydroxide into the secondary reaction tank, and adjusting the pH value of the solution to 7.5;
and step S40, overflowing the liquid in the secondary reaction tank to a thickener for solid-liquid separation, pumping the supernatant of the thickener to a Siene filter after passing through an overflow weir, and overflowing to a regulating tank and a pit which is dug to a tail end treatment station to finish the defluorination of the wastewater.
The invention adopts the process of 'polymeric ferric sulfate + aluminum sulfate' to remove fluorine cooperatively, the main added agents in the fluorine removal process comprise lime, polymeric ferric sulfate, aluminum sulfate and PAM, and the fluorine removal principle of each agent is as follows:
(1) principle of removing fluorine from aluminum sulfate
The aluminum sulfate hydrolyzate has [ Al (H)2O)6]3+、[Al(OH)(H2O)5]2+、[Al2(OH)2(H2O)8]4+、[Al3(OH)5(H2O)9]4+、[Al3(OH)4]5+、[Al7(OH)17]4+、[Al13O4(OH)17]7+And adsorbing F-in the wastewater through electrostatic action by various high-valence cations. Wherein the hydrolysate A1(OH)3Is a colloid, and is easy to adsorb F due to large surface area-Thereby forming a coprecipitation.
(2) Defluorination principle of polymeric ferric sulfate
Because the content of As in the wastewater is higher, in order to reduce the influence of As on the whole defluorination process, a certain amount of polymeric ferric sulfate is added to reduce the content of As in the wastewater, and then the wastewater is defluorinated, so that the defluorination efficiency is improved. Fe in polymeric ferric sulfate3+Reacts with arsenous acid and arsenic acid in the wastewater to generate ferric arsenite and ferric arsenate precipitates, and the reaction is as follows:
(3) principle of lime defluorination
Adjusting the pH of the wastewater by lime and adding Ca in the lime2+With F in the waste water－The reaction produced a precipitate as follows:
Ca(OH)2→Ca2++2OH-
CaCl2→Ca2++2Cl-
Ca2++2F－→CaF2↓
(4) principle of increasing defluorination efficiency by PAM
The colloid particles suspended in water can generate effective adsorption and bridging action, and form flocculating constituent.
Further, in step S10, the amount of aluminum sulfate added is 0.5 to 2 g/L.
Further, in step S20, the amount of the polymeric ferric sulfate added is 0.8g/L to 3.5 g/L.
Further, in step S40, a flocculant is added before the liquid overflows to the thickener.
Furthermore, the flocculant is a PAM flocculant with the molecular weight of 800-1800 ten thousand.
Furthermore, the flocculant is a composite flocculant; the preparation method of the composite flocculant comprises the following steps: dissolving aluminum chloride in water, heating to 45 ℃, stirring and mixing, dropwise adding a sodium hydroxide solution with the concentration of 0.35-0.55 mol/L, and reacting for 1 hour to obtain polyaluminum chloride; adding an aqueous solution of ferric chloride hexahydrate into polyaluminum chloride, continuously reacting for 6-8 hours, and curing for 24 hours to obtain a polyaluminum ferric chloride solution; adding 200 parts of modified starch into water, stirring and dispersing at 45 ℃, adding 150-350 parts of polyaluminum ferric chloride solution, stirring and mixing for 1-2 hours, and drying at 50 ℃ to obtain the composite flocculant.
Wherein, Fe3+And Al3+The atomic covalent radius and the ionic radius of the flocculant are close to each other and have the same charge, the corresponding salts of the flocculant have covalent property, a multinuclear and stable molecular chain can be formed through cross copolymerization, and the obtained flocculant has better flocculation effect, high flocculation speed, large formed floccule and high sedimentation speed.
Furthermore, the alkalization degree of the polyaluminum ferric chloride solution is 1.5, and the molar ratio of aluminum ions to iron ions in the polyaluminum ferric chloride solution is (5-7): (3-5).
Further, the preparation of the modified starch comprises the following steps: adding corn starch into an ethanol solution, stirring and dispersing for 10 minutes, heating to 38 ℃, adding sodium hydroxide, continuously stirring and mixing for 30-50 minutes, sequentially adding an isopropanol solution of monochloroacetic acid and sodium hydroxide, heating to 45-50 ℃, reacting for 60-120 minutes, adjusting the pH value to be neutral by using acetic acid, washing by using ethanol until no chloride ion exists, filtering, and drying in vacuum to obtain the modified starch.
Wherein, the flocculating agent is also added with a modified adsorbent; the preparation of the modified adsorbent comprises the following steps: mixing activated carbon and activated clay according to a weight ratio of 10: 3-6 to obtain mixed powder; adding chitosan into acetic acid solution with the concentration of 0.5-2.5% to obtain chitosan colloidal fluid; adding the mixed powder into chitosan colloidal fluid, processing for 2 hours at room temperature, stirring to be pasty, vacuum drying, putting into an oven, activating for 2 hours at 280-320 ℃, grinding and sieving to obtain the modified adsorbent
The invention has the advantages that:
(1) the invention removes Fe in the preparation by fluorine3+And the hydrolysate of aluminum sulfate solution and As in the wastewater-、F-Insoluble precipitate and colloid are formed in a reaction and electric adsorption mode, so that the content of fluorine in the wastewater is reduced;
(2) the wastewater defluorination process system is put into normal use, the original wastewater is treated by the newly added defluorination process system, the fluorine content in the wastewater is reduced to be within 5mg/L, and the wastewater can meet the discharge standard of industrial pollutants of copper, cobalt and nickel of GB 25467-2010, and the environmental protection benefit of a company is greatly improved.
In addition to the objects, features and advantages described above, other objects, features and advantages of the present invention are also provided. The present invention will be described in further detail below.
Drawings
FIG. 1 is a flow chart of the wastewater defluorination process of the invention.
Detailed Description
The following detailed description of embodiments of the invention, but the invention can be practiced in many different ways, as defined and covered by the claims.
Example 1
Defluorination process for washing smelting flue gas wastewater
The defluorination process for washing the smelting flue gas wastewater comprises the following steps:
step S10, conveying the high-fluorine wastewater treated by the neutralization process from the intermediate tank of the neutralization process to a primary reaction tank through a pump, adding aluminum sulfate into the primary reaction tank, and carrying out reaction treatment for 4.5 hours;
step S20, overflowing the liquid in the primary reaction tank into an oxidation tank, adding polymeric ferric sulfate, and fully reacting the polymeric ferric sulfate with the wastewater under the stirring effect;
step S30, overflowing the liquid in the oxidation tank to a secondary reaction tank, adding calcium hydroxide into the secondary reaction tank, and adjusting the pH value of the solution to 7.5;
and step S40, overflowing the liquid in the secondary reaction tank to a thickener for solid-liquid separation, pumping the supernatant of the thickener to a Siene filter after passing through an overflow weir, and overflowing to a regulating tank and a pit which is dug to a tail end treatment station to finish the defluorination of the wastewater.
The content of fluorine ions in the high-fluorine wastewater treated by the neutralization process is 25.64mg/L, and after the defluorination process is adopted, the content of fluorine ions is 1.38 mg/L.
Example 2
Defluorination process for washing smelting flue gas wastewater
The defluorination process for washing the smelting flue gas wastewater comprises the following steps:
step S10, conveying the high-fluorine wastewater treated by the neutralization process from the intermediate tank of the neutralization process to a primary reaction tank through a pump, adding aluminum sulfate into the primary reaction tank, and carrying out reaction treatment for 3 hours;
step S20, overflowing the liquid in the primary reaction tank into an oxidation tank, adding polymeric ferric sulfate, and fully reacting the polymeric ferric sulfate with the wastewater under the stirring effect;
step S30, overflowing the liquid in the oxidation tank to a secondary reaction tank, adding calcium hydroxide into the secondary reaction tank, and adjusting the pH value of the solution to 7.5;
step S40, overflowing the liquid in the secondary reaction tank to a flocculation tank, and adding a flocculating agent PAM;
and step S50, overflowing the liquid from the flocculation tank to a thickener for solid-liquid separation, pumping the supernatant of the thickener to a Siene filter after passing through an overflow weir, and overflowing to a treatment station at the tail end of a pit of an adjusting tank to finish the defluorination of the wastewater.
The content of fluorine ions in the high-fluorine wastewater treated by the neutralization process is 31.52mg/L, and after the defluorination process is adopted, the content of fluorine ions is 2.07 mg/L.
Example 3
Defluorination process for washing smelting flue gas wastewater
The defluorination process for washing the smelting flue gas wastewater comprises the following steps:
step S10, conveying the high-fluorine wastewater treated by the neutralization process from the intermediate tank of the neutralization process to a primary reaction tank through a pump, adding aluminum sulfate into the primary reaction tank, and carrying out reaction treatment for 6 hours;
step S20, overflowing the liquid in the primary reaction tank into an oxidation tank, adding polymeric ferric sulfate, and fully reacting the polymeric ferric sulfate with the wastewater under the stirring effect;
step S30, overflowing the liquid in the oxidation tank to a secondary reaction tank, adding calcium hydroxide into the secondary reaction tank, and adjusting the pH value of the solution to 7.5;
step S40, overflowing the liquid in the secondary reaction tank to a flocculation tank, and adding a flocculating agent PAM;
and step S50, overflowing the liquid in the flocculation tank to a thickener for solid-liquid separation, pumping the supernatant of the thickener to a Siene filter after passing through an overflow weir, and overflowing to a pit of an adjusting tank to finish a tail end treatment station to finish the defluorination of the wastewater.
The content of fluorine ions in the high-fluorine wastewater treated by the neutralization process is 38.78.64mg/L, and after the defluorination process is adopted, the content of fluorine ions is 1.11 mg/L.
Example 4
Defluorination process for washing smelting flue gas wastewater
The defluorination process for washing the smelting flue gas wastewater comprises the following steps:
step S10, conveying the high-fluorine wastewater treated by the neutralization process from the intermediate tank of the neutralization process to a primary reaction tank through a pump, adding aluminum sulfate into the primary reaction tank, wherein the addition amount of the aluminum sulfate is 0.5g/L, and carrying out reaction treatment for 3 hours;
step S20, overflowing the liquid in the primary reaction tank into an oxidation tank, adding polymeric ferric sulfate, wherein the addition amount of the polymeric ferric sulfate is 0.8g/L, and fully reacting the polymeric ferric sulfate with the wastewater through the stirring effect;
step S30, overflowing the liquid in the oxidation tank to a secondary reaction tank, adding calcium hydroxide into the secondary reaction tank, and adjusting the pH value of the solution to 7.5;
step S40, overflowing the liquid in the secondary reaction tank to a flocculation tank, and adding a flocculant, wherein the flocculant is a PAM flocculant with the molecular weight of 800-1800 ten thousand;
and step S50, overflowing the liquid in the flocculation tank to a thickener for solid-liquid separation, pumping the supernatant of the thickener to a Siene filter after passing through an overflow weir, and overflowing to a pit of an adjusting tank to finish a tail end treatment station to finish the defluorination of the wastewater.
The content of fluorine ions in the high-fluorine wastewater treated by the neutralization process is 40.55mg/L, and after the defluorination process is adopted, the content of fluorine ions is 1.79 mg/L.
Example 5
Defluorination process for washing smelting flue gas wastewater
The defluorination process for washing the smelting flue gas wastewater comprises the following steps:
step S10, conveying the high-fluorine wastewater treated by the neutralization process from the intermediate tank of the neutralization process to a primary reaction tank through a pump, adding aluminum sulfate into the primary reaction tank, wherein the addition amount of the aluminum sulfate is 2g/L, and carrying out reaction treatment for 6 hours;
step S20, overflowing the liquid in the primary reaction tank into an oxidation tank, adding polymeric ferric sulfate, wherein the addition amount of the polymeric ferric sulfate is 3.5g/L, and fully reacting the polymeric ferric sulfate with the wastewater through the stirring effect;
step S30, overflowing the liquid in the oxidation tank to a secondary reaction tank, adding calcium hydroxide into the secondary reaction tank, and adjusting the pH value of the solution to 7.5;
step S40, overflowing the liquid in the secondary reaction tank to a flocculation tank, and adding a composite flocculant;
and step S50, overflowing the liquid in the flocculation tank to a thickener for solid-liquid separation, pumping the supernatant of the thickener to a Siene filter after passing through an overflow weir, and overflowing to a pit of an adjusting tank to finish a tail end treatment station to finish the defluorination of the wastewater.
The preparation method of the composite flocculant comprises the following steps: dissolving aluminum chloride in water, heating to 45 ℃, stirring and mixing, dropwise adding a sodium hydroxide solution with the concentration of 0.35mol/L, and reacting for 1 hour to obtain polyaluminum chloride; adding the aqueous solution of ferric chloride hexahydrate into polyaluminium chloride, continuously reacting for 6 hours, and curing for 24 hours to obtain a polyaluminium chloride ferric solution; adding 200 parts of modified starch into water, stirring and dispersing at 45 ℃, adding 150 parts of polyaluminum ferric chloride solution, stirring and mixing for 1 hour, and drying at 50 ℃ to obtain a composite flocculant; the alkalization degree of the polyaluminum ferric chloride solution is 1.5, and the molar ratio of aluminum ions to iron ions in the polyaluminum ferric chloride solution is 5: 5;
the preparation of the modified starch comprises the following steps: adding corn starch into an ethanol solution, stirring and dispersing for 10 minutes, heating to 38 ℃, adding sodium hydroxide, continuously stirring and mixing for 30 minutes, sequentially adding an isopropanol solution of monochloroacetic acid and sodium hydroxide, heating to 45 ℃, reacting for 60 minutes, adjusting the pH to be neutral by using acetic acid, washing by using ethanol until no chloride ion exists, filtering, and drying in vacuum to obtain the modified starch.
When the content of fluorine ions in the high-fluorine wastewater treated by the neutralization process is greater than 40mg/L, the use type of the flocculant is changed, the composite flocculant prepared by the embodiment is used for treatment, the composite flocculant is prepared by taking aluminum chloride, ferric trichloride and modified starch as raw materials, and the polymeric aluminum-iron composite flocculant has the characteristics of both ferric salt and aluminum salt flocculant, has the characteristics of high reaction speed, large formed flocculating body, high sedimentation speed and the like, is matched with grafted modified starch, has a certain adsorption effect, improves the flocculation effect, and can also remove COD (chemical oxygen demand) in the wastewater. The content of fluorine ions in the high-fluorine wastewater treated by the neutralization process is 62.67mg/L, and after the defluorination process is adopted, the content of fluorine ions is 2.14 mg/L.
Example 6
Defluorination process for washing smelting flue gas wastewater
The defluorination process for washing the smelting flue gas wastewater comprises the following steps:
step S10, conveying the high-fluorine wastewater treated by the neutralization process from the intermediate tank of the neutralization process to a primary reaction tank through a pump, adding aluminum sulfate into the primary reaction tank, wherein the addition amount of the aluminum sulfate is 1.2g/L, and carrying out reaction treatment for 4.5 hours;
step S20, overflowing the liquid in the primary reaction tank into an oxidation tank, adding polyferric sulfate, wherein the adding amount of the polyferric sulfate is 2.2g/L, and fully reacting the polyferric sulfate with the wastewater under the stirring action;
step S30, overflowing the liquid in the oxidation tank to a secondary reaction tank, adding calcium hydroxide into the secondary reaction tank, and adjusting the pH value of the solution to 7.5;
step S40, overflowing the liquid in the secondary reaction tank to a flocculation tank, and adding a composite flocculant;
and step S50, overflowing the liquid in the flocculation tank to a thickener for solid-liquid separation, pumping the supernatant of the thickener to a Siene filter after passing through an overflow weir, and overflowing to a pit of an adjusting tank to finish a tail end treatment station to finish the defluorination of the wastewater.
The preparation method of the composite flocculant comprises the following steps: dissolving aluminum chloride in water, heating to 45 ℃, stirring and mixing, dropwise adding a sodium hydroxide solution with the concentration of 0.55mol/L, and reacting for 1 hour to obtain polyaluminum chloride; adding the aqueous solution of ferric chloride hexahydrate into polyaluminium chloride, continuously reacting for 8 hours, and curing for 24 hours to obtain a polyaluminium chloride ferric solution; adding 200 parts of modified starch into water, stirring and dispersing at 45 ℃, adding 350 parts of polyaluminum ferric chloride solution, stirring and mixing for 2 hours, and drying at 50 ℃ to obtain a composite flocculant; the alkalization degree of the polyaluminum ferric chloride solution is 1.5, and the molar ratio of aluminum ions to iron ions in the polyaluminum ferric chloride solution is 7: 3;
the preparation of the modified starch comprises the following steps: adding corn starch into an ethanol solution, stirring and dispersing for 10 minutes, heating to 38 ℃, adding sodium hydroxide, continuously stirring and mixing for 50 minutes, sequentially adding an isopropanol solution of monochloroacetic acid and sodium hydroxide, heating to 50 ℃, reacting for 120 minutes, adjusting the pH to be neutral by using acetic acid, washing by using ethanol until no chloride ion exists, filtering, and drying in vacuum to obtain the modified starch.
When the content of fluorine ions in the high-fluorine wastewater treated by the neutralization process is greater than 40mg/L, the use type of the flocculant is changed, the composite flocculant prepared by the embodiment is used for treatment, the composite flocculant is prepared by taking aluminum chloride, ferric trichloride and modified starch as raw materials, and the polymeric aluminum-iron composite flocculant has the characteristics of both ferric salt and aluminum salt flocculant, has the characteristics of high reaction speed, large formed flocculating body, high sedimentation speed and the like, is matched with grafted modified starch, has a certain adsorption effect, improves the flocculation effect, and can also remove COD (chemical oxygen demand) in the wastewater. The content of fluorine ions in the high-fluorine wastewater treated by the neutralization process is 74.66mg/L, and after the defluorination process is adopted, the content of fluorine ions is 1.35 mg/L.
Example 7
Defluorination process for washing smelting flue gas wastewater
The defluorination process for washing the smelting flue gas wastewater comprises the following steps:
step S10, conveying the high-fluorine wastewater treated by the neutralization process from the intermediate tank of the neutralization process to a primary reaction tank through a pump, adding aluminum sulfate into the primary reaction tank, wherein the addition amount of the aluminum sulfate is 1.2g/L, and carrying out reaction treatment for 4.5 hours;
step S20, overflowing the liquid in the primary reaction tank into an oxidation tank, adding polyferric sulfate, wherein the adding amount of the polyferric sulfate is 2.2g/L, and fully reacting the polyferric sulfate with the wastewater under the stirring action;
step S30, overflowing the liquid in the oxidation tank to a secondary reaction tank, adding calcium hydroxide into the secondary reaction tank, and adjusting the pH value of the solution to 7.5;
step S40, overflowing the liquid in the secondary reaction tank to a flocculation tank, and adding a composite flocculant;
and step S50, overflowing the liquid in the flocculation tank to a thickener for solid-liquid separation, pumping the supernatant of the thickener to a Siene filter after passing through an overflow weir, and overflowing to a pit of an adjusting tank to finish a tail end treatment station to finish the defluorination of the wastewater.
The preparation method of the composite flocculant comprises the following steps: dissolving aluminum chloride in water, heating to 45 ℃, stirring and mixing, dropwise adding a sodium hydroxide solution with the concentration of 0.45mol/L, and reacting for 1 hour to obtain polyaluminum chloride; adding the aqueous solution of ferric chloride hexahydrate into polyaluminium chloride, continuously reacting for 7 hours, and curing for 24 hours to obtain a polyaluminium chloride ferric solution; adding 200 parts of modified starch into water, stirring and dispersing at 45 ℃, adding 250 parts of polyaluminum ferric chloride solution, stirring and mixing for 1.5 hours, and drying at 50 ℃ to obtain a composite flocculant; the alkalization degree of the polyaluminum ferric chloride solution is 1.5, and the molar ratio of aluminum ions to iron ions in the polyaluminum ferric chloride solution is 6: 4;
the preparation of the modified starch comprises the following steps: adding corn starch into an ethanol solution, stirring and dispersing for 10 minutes, heating to 38 ℃, adding sodium hydroxide, continuously stirring and mixing for 40 minutes, sequentially adding an isopropanol solution of monochloroacetic acid and sodium hydroxide, heating to 48 ℃, reacting for 90 minutes, adjusting the pH value to be neutral by using acetic acid, washing by using ethanol until no chloride ion exists, filtering, and drying in vacuum to obtain the modified starch.
When the content of fluorine ions in the high-fluorine wastewater treated by the neutralization process is greater than 40mg/L, the use type of the flocculant is changed, the composite flocculant prepared by the embodiment is used for treatment, the composite flocculant is prepared by taking aluminum chloride, ferric trichloride and modified starch as raw materials, and the polymeric aluminum-iron composite flocculant has the characteristics of both ferric salt and aluminum salt flocculant, has the characteristics of high reaction speed, large formed flocculating body, high sedimentation speed and the like, is matched with grafted modified starch, has a certain adsorption effect, improves the flocculation effect, and can also remove COD (chemical oxygen demand) in the wastewater. The content of fluorine ions in the high-fluorine wastewater treated by the neutralization process is 67.83mg/L, and after the defluorination process is adopted, the content of fluorine ions is 2.16 mg/L.
Example 8
Defluorination process for washing smelting flue gas wastewater
The defluorination process for washing the smelting flue gas wastewater comprises the following steps:
step S10, conveying the high-fluorine wastewater treated by the neutralization process from the intermediate tank of the neutralization process to a primary reaction tank through a pump, adding aluminum sulfate into the primary reaction tank, wherein the addition amount of the aluminum sulfate is 1.2g/L, and carrying out reaction treatment for 4.5 hours;
step S20, overflowing the liquid in the primary reaction tank into an oxidation tank, adding polyferric sulfate, wherein the adding amount of the polyferric sulfate is 2.2g/L, and fully reacting the polyferric sulfate with the wastewater under the stirring action;
step S30, overflowing the liquid in the oxidation tank to a secondary reaction tank, adding calcium hydroxide into the secondary reaction tank, and adjusting the pH value of the solution to 7.5;
step S40, overflowing the liquid in the secondary reaction tank to a flocculation tank, and adding a composite flocculant and a modified adsorbent;
and step S50, overflowing the liquid in the flocculation tank to a thickener for solid-liquid separation, pumping the supernatant of the thickener to a Siene filter after passing through an overflow weir, and overflowing to a pit of an adjusting tank to finish a tail end treatment station to finish the defluorination of the wastewater.
The preparation method of the composite flocculant comprises the following steps: dissolving aluminum chloride in water, heating to 45 ℃, stirring and mixing, dropwise adding a sodium hydroxide solution with the concentration of 0.45mol/L, and reacting for 1 hour to obtain polyaluminum chloride; adding the aqueous solution of ferric chloride hexahydrate into polyaluminium chloride, continuously reacting for 7 hours, and curing for 24 hours to obtain a polyaluminium chloride ferric solution; adding 200 parts of modified starch into water, stirring and dispersing at 45 ℃, adding 250 parts of polyaluminum ferric chloride solution, stirring and mixing for 1.5 hours, and drying at 50 ℃ to obtain a composite flocculant; the alkalization degree of the polyaluminum ferric chloride solution is 1.5, and the molar ratio of aluminum ions to iron ions in the polyaluminum ferric chloride solution is 6: 4;
the preparation of the modified starch comprises the following steps: adding corn starch into an ethanol solution, stirring and dispersing for 10 minutes, heating to 38 ℃, adding sodium hydroxide, continuously stirring and mixing for 30-50 minutes, sequentially adding an isopropanol solution of monochloroacetic acid and sodium hydroxide, heating to 48 ℃, reacting for 90 minutes, adjusting the pH value to be neutral by using acetic acid, washing by using ethanol until no chloride ion exists, filtering, and drying in vacuum to obtain modified starch;
the preparation of the modified adsorbent comprises the following steps: mixing activated carbon and activated clay according to a weight ratio of 10:3 to obtain mixed powder; adding chitosan into 0.5% acetic acid solution to obtain chitosan colloidal solution; and adding the mixed powder into chitosan colloidal fluid, treating for 2 hours at room temperature, stirring to be pasty, vacuum drying, putting into an oven, activating for 2 hours at 280 ℃, grinding and sieving to obtain the modified adsorbent.
When the content of fluorine ions in the high-fluorine wastewater treated by the neutralization process is more than 40mg/L, changing the use type of the flocculant, and treating by using the composite flocculant prepared by the embodiment, wherein the composite flocculant takes aluminum chloride, ferric trichloride and modified starch as raw materials to prepare the composite flocculant, and the polymeric aluminum-iron composite flocculant has the characteristics of both ferric salt and aluminum salt flocculant, has the characteristics of high reaction speed, large formed flocculating body, high sedimentation speed and the like, and has a certain adsorption effect by matching with the grafted modified starch, so that the flocculation effect is improved, and COD in the wastewater can be removed; when the content of fluorine ions in the treated wastewater is higher and is more than 80mg/L, a modified adsorbent can be added on the basis of adding the composite flocculant, active carbon and active daytime are taken as main raw materials, and chitosan is grafted, so that the adsorption effect on the fluorine ions is enhanced.
The fluorine ion content in the high-fluorine wastewater treated by the neutralization process is 80.83mg/L, and after the defluorination process is adopted, the fluorine ion content is 1.04 mg/L.
Example 9
Defluorination process for washing smelting flue gas wastewater
The defluorination process for washing the smelting flue gas wastewater comprises the following steps:
step S10, conveying the high-fluorine wastewater treated by the neutralization process from the intermediate tank of the neutralization process to a primary reaction tank through a pump, adding aluminum sulfate into the primary reaction tank, wherein the addition amount of the aluminum sulfate is 1.2g/L, and carrying out reaction treatment for 4.5 hours;
step S20, overflowing the liquid in the primary reaction tank into an oxidation tank, adding polyferric sulfate, wherein the adding amount of the polyferric sulfate is 2.2g/L, and fully reacting the polyferric sulfate with the wastewater under the stirring action;
step S30, overflowing the liquid in the oxidation tank to a secondary reaction tank, adding calcium hydroxide into the secondary reaction tank, and adjusting the pH value of the solution to 7.5;
step S40, overflowing the liquid in the secondary reaction tank to a flocculation tank, and adding a composite flocculant and a modified adsorbent;
and step S50, overflowing the liquid in the flocculation tank to a thickener for solid-liquid separation, pumping the supernatant of the thickener to a Siene filter after passing through an overflow weir, and overflowing to a pit of an adjusting tank to finish a tail end treatment station to finish the defluorination of the wastewater.
Wherein the flocculating agent is a composite flocculating agent; the preparation method of the composite flocculant comprises the following steps: dissolving aluminum chloride in water, heating to 45 ℃, stirring and mixing, dropwise adding a sodium hydroxide solution with the concentration of 0.45mol/L, and reacting for 1 hour to obtain polyaluminum chloride; adding the aqueous solution of ferric chloride hexahydrate into polyaluminium chloride, continuously reacting for 7 hours, and curing for 24 hours to obtain a polyaluminium chloride ferric solution; adding 200 parts of modified starch into water, stirring and dispersing at 45 ℃, adding 250 parts of polyaluminum ferric chloride solution, stirring and mixing for 1.5 hours, and drying at 50 ℃ to obtain a composite flocculant; the alkalization degree of the polyaluminum ferric chloride solution is 1.5, and the molar ratio of aluminum ions to iron ions in the polyaluminum ferric chloride solution is 6: 4;
the preparation of the modified starch comprises the following steps: adding corn starch into an ethanol solution, stirring and dispersing for 10 minutes, heating to 38 ℃, adding sodium hydroxide, continuously stirring and mixing for 40 minutes, sequentially adding an isopropanol solution of monochloroacetic acid and sodium hydroxide, heating to 48 ℃, reacting for 90 minutes, adjusting the pH to be neutral by using acetic acid, washing by using ethanol until no chloride ion exists, filtering, and drying in vacuum to obtain modified starch;
the preparation of the modified adsorbent comprises the following steps: mixing activated carbon and activated clay according to a weight ratio of 10:6 to obtain mixed powder; adding chitosan into 2.5% acetic acid solution to obtain chitosan colloidal fluid; and adding the mixed powder into chitosan colloidal fluid, treating for 2 hours at room temperature, stirring to be pasty, vacuum drying, putting into an oven, activating for 2 hours at 320 ℃, grinding and sieving to obtain the modified adsorbent.
The content of fluorine ions in the high-fluorine wastewater treated by the neutralization process is 80.83mg/L, and after the defluorination process is adopted, the content of fluorine ions is 1.35 mg/L.
Example 10
Defluorination process for washing smelting flue gas wastewater
The defluorination process for washing the smelting flue gas wastewater comprises the following steps:
step S10, conveying the high-fluorine wastewater treated by the neutralization process from the intermediate tank of the neutralization process to a primary reaction tank through a pump, adding aluminum sulfate into the primary reaction tank, wherein the addition amount of the aluminum sulfate is 1.2g/L, and carrying out reaction treatment for 4.5 hours;
step S20, overflowing the liquid in the primary reaction tank into an oxidation tank, adding polyferric sulfate, wherein the adding amount of the polyferric sulfate is 2.2g/L, and fully reacting the polyferric sulfate with the wastewater under the stirring action;
step S30, overflowing the liquid in the oxidation tank to a secondary reaction tank, adding calcium hydroxide into the secondary reaction tank, and adjusting the pH value of the solution to 7.5;
step S40, overflowing the liquid in the secondary reaction tank to a flocculation tank, and adding a composite flocculant and a modified adsorbent;
and step S50, overflowing the liquid in the flocculation tank to a thickener for solid-liquid separation, pumping the supernatant of the thickener to a Siene filter after passing through an overflow weir, and overflowing to a pit of an adjusting tank to finish a tail end treatment station to finish the defluorination of the wastewater.
Wherein the flocculating agent is a composite flocculating agent; the preparation method of the composite flocculant comprises the following steps: dissolving aluminum chloride in water, heating to 45 ℃, stirring and mixing, dropwise adding a sodium hydroxide solution with the concentration of 0.45mol/L, and reacting for 1 hour to obtain polyaluminum chloride; adding the aqueous solution of ferric chloride hexahydrate into polyaluminium chloride, continuously reacting for 7 hours, and curing for 24 hours to obtain a polyaluminium chloride ferric solution; adding 200 parts of modified starch into water, stirring and dispersing at 45 ℃, adding 250 parts of polyaluminum ferric chloride solution, stirring and mixing for 1.5 hours, and drying at 50 ℃ to obtain a composite flocculant; the alkalization degree of the polyaluminum ferric chloride solution is 1.5, and the molar ratio of aluminum ions to iron ions in the polyaluminum ferric chloride solution is 6: 4;
the preparation of the modified starch comprises the following steps: adding corn starch into an ethanol solution, stirring and dispersing for 10 minutes, heating to 38 ℃, adding sodium hydroxide, continuously stirring and mixing for 40 minutes, sequentially adding an isopropanol solution of monochloroacetic acid and sodium hydroxide, heating to 48 ℃, reacting for 90 minutes, adjusting the pH to be neutral by using acetic acid, washing by using ethanol until no chloride ion exists, filtering, and drying in vacuum to obtain modified starch;
the preparation of the modified adsorbent comprises the following steps: mixing activated carbon and activated clay according to a weight ratio of 10:4.5 to obtain mixed powder; adding chitosan into 1.5% acetic acid solution to obtain chitosan colloidal fluid; and adding the mixed powder into chitosan colloidal fluid, treating for 2 hours at room temperature, stirring to be pasty, vacuum drying, putting into an oven, activating for 2 hours at 300 ℃, grinding and sieving to obtain the modified adsorbent.
The content of fluorine ions in the high-fluorine wastewater treated by the neutralization process is 80.83mg/L, and after the defluorination process is adopted, the content of fluorine ions is 1.25 mg/L.
The above is only a preferred embodiment of the present invention, and is not intended to limit the present invention, and various modifications and changes will occur to those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (8)
1. A defluorination process for washing smelting flue gas wastewater is characterized by comprising the following steps:
step S10, conveying the high-fluorine wastewater treated by the neutralization process from the intermediate tank of the neutralization process to a primary reaction tank through a pump, adding aluminum sulfate into the primary reaction tank, and carrying out reaction treatment for 3-6 hours;
step S20, overflowing the liquid in the primary reaction tank into an oxidation tank, adding polymeric ferric sulfate, and fully reacting the polymeric ferric sulfate with the wastewater under the stirring effect;
step S30, overflowing the liquid in the oxidation tank to a secondary reaction tank, adding calcium hydroxide into the secondary reaction tank, and adjusting the pH value of the solution to 7.5;
and step S40, overflowing the liquid in the secondary reaction tank to a thickener for solid-liquid separation, pumping the supernatant of the thickener to a Siene filter after passing through an overflow weir, and overflowing to a treatment station at the tail end of a pit of an adjusting tank to finish the defluorination of the wastewater.
2. The process of claim 1, wherein in step S10, the addition amount of aluminum sulfate is 0.5 g/L-2 g/L.
3. The process of claim 1, wherein in step S20, the amount of polymeric ferric sulfate added is 0.8 g/L-3.5 g/L.
4. The process of claim 1, wherein in step S40, a flocculating agent is added before the liquid overflows to the thickener.
5. The process for defluorinating waste water from washing metallurgical off-gas according to claim 4, wherein the flocculant is a PAM flocculant having a molecular weight of 800-1800 ten thousand.
6. The process for removing fluorine from waste water generated by washing metallurgical off-gas according to claim 4, wherein the flocculating agent is a composite flocculating agent; the preparation method of the composite flocculant comprises the following steps: dissolving aluminum chloride in water, heating to 45 ℃, stirring and mixing, dropwise adding a sodium hydroxide solution with the concentration of 0.35-0.55 mol/L, and reacting for 1 hour to obtain polyaluminum chloride; adding an aqueous solution of ferric chloride hexahydrate into polyaluminum chloride, continuously reacting for 6-8 hours, and curing for 24 hours to obtain a polyaluminum ferric chloride solution; adding 200 parts of modified starch into water, stirring and dispersing at 45 ℃, adding 150-350 parts of polyaluminum ferric chloride solution, stirring and mixing for 1-2 hours, and drying at 50 ℃ to obtain the composite flocculant.
7. The defluorination process for washing smelting flue gas wastewater according to claim 6, wherein the alkalization degree of the polyaluminum ferric chloride solution is 1.5, and the molar ratio of aluminum ions to iron ions in the polyaluminum ferric chloride solution is (5-7): (3-5).
8. The process for removing fluorine from waste water generated in washing smelting flue gas of claim 6, wherein the preparation of the modified starch comprises the following steps: adding corn starch into an ethanol solution, stirring and dispersing for 10 minutes, heating to 38 ℃, adding sodium hydroxide, continuously stirring and mixing for 30-50 minutes, sequentially adding an isopropanol solution of monochloroacetic acid and sodium hydroxide, heating to 45-50 ℃, reacting for 60-120 minutes, adjusting the pH value to be neutral by using acetic acid, washing by using ethanol until no chloride ion exists, filtering, and drying in vacuum to obtain the modified starch.
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN117303536A (en) * | 2023-11-29 | 2023-12-29 | 河北协同水处理技术有限公司 | Coking wastewater liquid defluorinating agent and preparation method and application thereof |
| CN117303536B (en) * | 2023-11-29 | 2024-02-20 | 河北协同水处理技术有限公司 | Coking wastewater liquid defluorinating agent and preparation method and application thereof |
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Application publication date: 20210803 |