WO2024045536A1 - Method for recycling sludge containing calcium fluoride - Google Patents
Method for recycling sludge containing calcium fluoride Download PDFInfo
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- WO2024045536A1 WO2024045536A1 PCT/CN2023/079591 CN2023079591W WO2024045536A1 WO 2024045536 A1 WO2024045536 A1 WO 2024045536A1 CN 2023079591 W CN2023079591 W CN 2023079591W WO 2024045536 A1 WO2024045536 A1 WO 2024045536A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- calcium fluoride
- solid
- containing sludge
- citrate
- liquid
- Prior art date
Links
- WUKWITHWXAAZEY-UHFFFAOYSA-L calcium difluoride Chemical compound [F-].[F-].[Ca+2] WUKWITHWXAAZEY-UHFFFAOYSA-L 0.000 title claims abstract description 94
- 229910001634 calcium fluoride Inorganic materials 0.000 title claims abstract description 93
- 239000010802 sludge Substances 0.000 title claims abstract description 75
- 238000000034 method Methods 0.000 title claims abstract description 33
- 238000004064 recycling Methods 0.000 title claims abstract description 16
- 239000007788 liquid Substances 0.000 claims abstract description 52
- 239000007787 solid Substances 0.000 claims abstract description 44
- KRKNYBCHXYNGOX-UHFFFAOYSA-K Citrate Chemical compound [O-]C(=O)CC(O)(CC([O-])=O)C([O-])=O KRKNYBCHXYNGOX-UHFFFAOYSA-K 0.000 claims abstract description 33
- 239000003153 chemical reaction reagent Substances 0.000 claims abstract description 33
- 239000002253 acid Substances 0.000 claims abstract description 25
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 24
- 238000003756 stirring Methods 0.000 claims abstract description 23
- 238000000926 separation method Methods 0.000 claims abstract description 20
- 239000003513 alkali Substances 0.000 claims abstract description 12
- 238000002156 mixing Methods 0.000 claims abstract description 5
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 claims description 20
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 claims description 12
- KWYUFKZDYYNOTN-UHFFFAOYSA-M Potassium hydroxide Chemical compound [OH-].[K+] KWYUFKZDYYNOTN-UHFFFAOYSA-M 0.000 claims description 9
- KRKNYBCHXYNGOX-UHFFFAOYSA-N citric acid Chemical compound OC(=O)CC(O)(C(O)=O)CC(O)=O KRKNYBCHXYNGOX-UHFFFAOYSA-N 0.000 claims description 9
- CDBYLPFSWZWCQE-UHFFFAOYSA-L Sodium Carbonate Chemical compound [Na+].[Na+].[O-]C([O-])=O CDBYLPFSWZWCQE-UHFFFAOYSA-L 0.000 claims description 8
- UIIMBOGNXHQVGW-UHFFFAOYSA-M Sodium bicarbonate Chemical compound [Na+].OC([O-])=O UIIMBOGNXHQVGW-UHFFFAOYSA-M 0.000 claims description 4
- 229910000029 sodium carbonate Inorganic materials 0.000 claims description 4
- 235000011121 sodium hydroxide Nutrition 0.000 claims description 4
- 235000015165 citric acid Nutrition 0.000 claims description 3
- 235000011118 potassium hydroxide Nutrition 0.000 claims description 3
- VHUUQVKOLVNVRT-UHFFFAOYSA-N Ammonium hydroxide Chemical compound [NH4+].[OH-] VHUUQVKOLVNVRT-UHFFFAOYSA-N 0.000 claims description 2
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 claims description 2
- 235000011114 ammonium hydroxide Nutrition 0.000 claims description 2
- HWPKGOGLCKPRLZ-UHFFFAOYSA-M monosodium citrate Chemical compound [Na+].OC(=O)CC(O)(C([O-])=O)CC(O)=O HWPKGOGLCKPRLZ-UHFFFAOYSA-M 0.000 claims description 2
- 239000002524 monosodium citrate Substances 0.000 claims description 2
- 235000018342 monosodium citrate Nutrition 0.000 claims description 2
- 229910017604 nitric acid Inorganic materials 0.000 claims description 2
- 239000001508 potassium citrate Substances 0.000 claims description 2
- 229960002635 potassium citrate Drugs 0.000 claims description 2
- QEEAPRPFLLJWCF-UHFFFAOYSA-K potassium citrate (anhydrous) Chemical compound [K+].[K+].[K+].[O-]C(=O)CC(O)(CC([O-])=O)C([O-])=O QEEAPRPFLLJWCF-UHFFFAOYSA-K 0.000 claims description 2
- 235000011082 potassium citrates Nutrition 0.000 claims description 2
- 229910000030 sodium bicarbonate Inorganic materials 0.000 claims description 2
- 235000017557 sodium bicarbonate Nutrition 0.000 claims description 2
- NLJMYIDDQXHKNR-UHFFFAOYSA-K sodium citrate Chemical compound O.O.[Na+].[Na+].[Na+].[O-]C(=O)CC(O)(CC([O-])=O)C([O-])=O NLJMYIDDQXHKNR-UHFFFAOYSA-K 0.000 claims description 2
- 239000001509 sodium citrate Substances 0.000 claims description 2
- 235000011083 sodium citrates Nutrition 0.000 claims description 2
- YWYZEGXAUVWDED-UHFFFAOYSA-N triammonium citrate Chemical compound [NH4+].[NH4+].[NH4+].[O-]C(=O)CC(O)(CC([O-])=O)C([O-])=O YWYZEGXAUVWDED-UHFFFAOYSA-N 0.000 claims description 2
- 235000017550 sodium carbonate Nutrition 0.000 claims 1
- 229910052731 fluorine Inorganic materials 0.000 abstract description 11
- 239000011737 fluorine Substances 0.000 abstract description 11
- 239000012535 impurity Substances 0.000 abstract description 3
- PXGOKWXKJXAPGV-UHFFFAOYSA-N Fluorine Chemical compound FF PXGOKWXKJXAPGV-UHFFFAOYSA-N 0.000 abstract 1
- 239000002994 raw material Substances 0.000 abstract 1
- 239000011259 mixed solution Substances 0.000 description 26
- 239000002244 precipitate Substances 0.000 description 18
- 239000000203 mixture Substances 0.000 description 15
- 239000000243 solution Substances 0.000 description 12
- 239000000047 product Substances 0.000 description 11
- YCKRFDGAMUMZLT-UHFFFAOYSA-N Fluorine atom Chemical compound [F] YCKRFDGAMUMZLT-UHFFFAOYSA-N 0.000 description 10
- 238000002386 leaching Methods 0.000 description 10
- -1 citrate ions Chemical class 0.000 description 7
- YASYEJJMZJALEJ-UHFFFAOYSA-N Citric acid monohydrate Chemical compound O.OC(=O)CC(O)(C(O)=O)CC(O)=O YASYEJJMZJALEJ-UHFFFAOYSA-N 0.000 description 6
- 229960002303 citric acid monohydrate Drugs 0.000 description 6
- 239000011777 magnesium Substances 0.000 description 6
- BHPQYMZQTOCNFJ-UHFFFAOYSA-N Calcium cation Chemical compound [Ca+2] BHPQYMZQTOCNFJ-UHFFFAOYSA-N 0.000 description 5
- 229910001424 calcium ion Inorganic materials 0.000 description 5
- 230000000052 comparative effect Effects 0.000 description 5
- 229910052717 sulfur Inorganic materials 0.000 description 5
- KRHYYFGTRYWZRS-UHFFFAOYSA-M Fluoride anion Chemical compound [F-] KRHYYFGTRYWZRS-UHFFFAOYSA-M 0.000 description 4
- 239000002585 base Substances 0.000 description 4
- 229910052749 magnesium Inorganic materials 0.000 description 4
- 229910052710 silicon Inorganic materials 0.000 description 4
- 239000000126 substance Substances 0.000 description 4
- 239000002351 wastewater Substances 0.000 description 4
- 229910004261 CaF 2 Inorganic materials 0.000 description 3
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 description 3
- 239000004566 building material Substances 0.000 description 3
- 230000000536 complexating effect Effects 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 239000010436 fluorite Substances 0.000 description 3
- 238000005272 metallurgy Methods 0.000 description 3
- 239000011593 sulfur Substances 0.000 description 3
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 description 2
- VTYYLEPIZMXCLO-UHFFFAOYSA-L Calcium carbonate Chemical compound [Ca+2].[O-]C([O-])=O VTYYLEPIZMXCLO-UHFFFAOYSA-L 0.000 description 2
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 description 2
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 2
- 230000002378 acidificating effect Effects 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 2
- 235000011116 calcium hydroxide Nutrition 0.000 description 2
- OSGAYBCDTDRGGQ-UHFFFAOYSA-L calcium sulfate Chemical compound [Ca+2].[O-]S([O-])(=O)=O OSGAYBCDTDRGGQ-UHFFFAOYSA-L 0.000 description 2
- 238000006243 chemical reaction Methods 0.000 description 2
- 229960004106 citric acid Drugs 0.000 description 2
- 238000010668 complexation reaction Methods 0.000 description 2
- 238000004090 dissolution Methods 0.000 description 2
- 230000007062 hydrolysis Effects 0.000 description 2
- 238000006460 hydrolysis reaction Methods 0.000 description 2
- 239000000843 powder Substances 0.000 description 2
- 238000001556 precipitation Methods 0.000 description 2
- 239000010703 silicon Substances 0.000 description 2
- 239000002910 solid waste Substances 0.000 description 2
- NWUYHJFMYQTDRP-UHFFFAOYSA-N 1,2-bis(ethenyl)benzene;1-ethenyl-2-ethylbenzene;styrene Chemical compound C=CC1=CC=CC=C1.CCC1=CC=CC=C1C=C.C=CC1=CC=CC=C1C=C NWUYHJFMYQTDRP-UHFFFAOYSA-N 0.000 description 1
- UXVMQQNJUSDDNG-UHFFFAOYSA-L Calcium chloride Chemical compound [Cl-].[Cl-].[Ca+2] UXVMQQNJUSDDNG-UHFFFAOYSA-L 0.000 description 1
- 229910021529 ammonia Inorganic materials 0.000 description 1
- 229910000019 calcium carbonate Inorganic materials 0.000 description 1
- 239000001110 calcium chloride Substances 0.000 description 1
- 229910001628 calcium chloride Inorganic materials 0.000 description 1
- AXCZMVOFGPJBDE-UHFFFAOYSA-L calcium dihydroxide Chemical compound [OH-].[OH-].[Ca+2] AXCZMVOFGPJBDE-UHFFFAOYSA-L 0.000 description 1
- 239000000920 calcium hydroxide Substances 0.000 description 1
- 229910001861 calcium hydroxide Inorganic materials 0.000 description 1
- 239000000378 calcium silicate Substances 0.000 description 1
- 229910052918 calcium silicate Inorganic materials 0.000 description 1
- OYACROKNLOSFPA-UHFFFAOYSA-N calcium;dioxido(oxo)silane Chemical compound [Ca+2].[O-][Si]([O-])=O OYACROKNLOSFPA-UHFFFAOYSA-N 0.000 description 1
- 238000009388 chemical precipitation Methods 0.000 description 1
- 238000005345 coagulation Methods 0.000 description 1
- 238000000909 electrodialysis Methods 0.000 description 1
- 238000005189 flocculation Methods 0.000 description 1
- 230000016615 flocculation Effects 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- 239000011521 glass Substances 0.000 description 1
- 239000003673 groundwater Substances 0.000 description 1
- 150000004679 hydroxides Chemical class 0.000 description 1
- 239000002440 industrial waste Substances 0.000 description 1
- 239000003456 ion exchange resin Substances 0.000 description 1
- 229920003303 ion-exchange polymer Polymers 0.000 description 1
- 238000010169 landfilling Methods 0.000 description 1
- 231100000053 low toxicity Toxicity 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
- 150000002739 metals Chemical class 0.000 description 1
- 238000000746 purification Methods 0.000 description 1
- 229960000999 sodium citrate dihydrate Drugs 0.000 description 1
- 239000002689 soil Substances 0.000 description 1
- 238000009270 solid waste treatment Methods 0.000 description 1
- 239000004575 stone Substances 0.000 description 1
- 231100000331 toxic Toxicity 0.000 description 1
- 230000002588 toxic effect Effects 0.000 description 1
- HRXKRNGNAMMEHJ-UHFFFAOYSA-K trisodium citrate Chemical compound [Na+].[Na+].[Na+].[O-]C(=O)CC(O)(CC([O-])=O)C([O-])=O HRXKRNGNAMMEHJ-UHFFFAOYSA-K 0.000 description 1
- 238000000108 ultra-filtration Methods 0.000 description 1
- 238000005406 washing Methods 0.000 description 1
- 239000002699 waste material 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
- C02F11/00—Treatment of sludge; Devices therefor
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01F—COMPOUNDS OF THE METALS BERYLLIUM, MAGNESIUM, ALUMINIUM, CALCIUM, STRONTIUM, BARIUM, RADIUM, THORIUM, OR OF THE RARE-EARTH METALS
- C01F11/00—Compounds of calcium, strontium, or barium
- C01F11/20—Halides
- C01F11/22—Fluorides
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
- Y02W10/00—Technologies for wastewater treatment
- Y02W10/30—Wastewater or sewage treatment systems using renewable energies
- Y02W10/37—Wastewater or sewage treatment systems using renewable energies using solar energy
Definitions
- the invention belongs to the technical field of solid waste treatment, and specifically relates to a method for recycling calcium fluoride-containing sludge.
- Calcium fluoride sludge is industrial solid waste, and the conventional treatment methods are landfill or incineration. Calcium fluoride has low toxicity, is slightly soluble in water, is easily absorbed by plants, and will contaminate soil and groundwater causing secondary pollution.
- the landfill method has limited processing capacity and extremely high requirements for landfill sites. It also causes a waste of fluorine resources and land resources. The process of treating fluorine-containing sludge by incineration will produce toxic fluorine-containing gases, which will also affect human health.
- Calcium fluoride also known as fluorspar, is currently mainly used in metallurgy, chemicals, building materials and other industries and is a non-renewable resource.
- industrial development has an increasing demand for calcium fluoride. Landfilling or incineration will prevent the effective utilization of calcium fluoride resources.
- the present invention aims to solve at least one of the technical problems existing in the above-mentioned prior art. To this end, the present invention proposes a method for recycling calcium fluoride-containing sludge, which can effectively purify calcium fluoride in the sludge and reduce the loss of fluorine in the sludge.
- a method for recycling calcium fluoride-containing sludge which includes the following steps:
- the first citrate reagent and the first acid solution are added, and the solid-liquid separation is carried out after stirring. The first solid is obtained.
- the second citrate reagent and the second acid liquid are added, and after stirring, the solid and liquid are separated to obtain the finished calcium fluoride product.
- the calcium fluoride-containing sludge is alkaline sludge, in which the proportion of CaF 2 on a dry basis is 45wt%-65wt%, and the proportions of S, Si, and Mg on a dry basis are all 1.5wt. %-3wt%.
- the mass ratio of each of the calcium fluoride-containing sludge, the first solid and the second solid mixed with water is independently 1: (10-20).
- the first citrate reagent and the second citrate reagent are independently at least one of citric acid, sodium citrate, sodium dihydrogen citrate, potassium citrate or ammonium citrate.
- the first acid liquid and the second acid liquid are independently at least one of hydrochloric acid and nitric acid.
- the mass ratio of the added amount of the first citrate reagent to the calcium fluoride-containing sludge is (0.01-0.3):1.
- the mass ratio of the added amount of the first citrate reagent to the calcium fluoride-containing sludge is (0.03-0.25):1.
- the pH of the mixed solution obtained after adding the first citrate reagent and the first acid solution is 2-7.
- the pH of the mixed solution obtained after adding the first citrate reagent and the first acid solution is 4-7.
- the stirring time is 30-80 minutes.
- the stirring time is 40-60 minutes.
- the first solid is also washed, dried and pulverized, and the The dry basis ratio of CaF 2 in the first solid is ⁇ 65wt%, the dry basis ratio of S is ⁇ 1.9wt%, and the dry basis ratio of Mg is ⁇ 0.3wt%.
- the base is at least one of sodium hydroxide, potassium hydroxide, ammonia, sodium carbonate or sodium bicarbonate.
- the base is at least one of sodium hydroxide, potassium hydroxide or ammonia water.
- the pH of the mixed solution obtained after adding the base is 8-13.
- the pH of the mixed solution obtained after adding the base is 9-12.
- the mass ratio of the added amount of the second citrate reagent to the calcium fluoride-containing sludge is (0.01-0.1):1.
- the mass ratio of the added amount of the second citrate reagent to the calcium fluoride-containing sludge is (0.01-0.05):1.
- the pH of the mixed solution obtained after adding the second citrate reagent and the second acid solution is 1-5.
- the pH of the mixed solution obtained after adding the second citrate reagent and the second acid solution is 2-4.
- the solid precipitate obtained is washed, dried and pulverized to obtain the finished calcium fluoride product. . Further, the washing involves rinsing the solid 3-5 times.
- the dry basis ratio of CaF 2 in the finished calcium fluoride product is ⁇ 85wt%, the dry basis ratio of S is ⁇ 1.9wt%, the dry basis ratio of Si is ⁇ 1.5wt%, and the dry basis ratio of Mg is ⁇ 1.5wt%. Dry basis proportion ⁇ 0.1wt%.
- the present invention mainly uses the complexation of citrate ions and calcium ions to purify calcium fluoride.
- the acid can remove the sludge.
- Most of them contain magnesium precipitates, which also partially dissolves silicon; citrate ions partially dissolve sulfur through complexing with calcium ions, while calcium fluoride has low solubility and less fluorine dissolves.
- the obtained calcium fluoride dry basis accounts for more than 65%, which can replace fluorspar powder ore used in chemical industry, metallurgy, building materials, machinery and other industries;
- the solid after solid-liquid separation in the previous step is mixed with water, an appropriate amount of alkali is added and stirred thoroughly, and the alkaline ring
- the environment inhibits the dissolution of fluorine, and at the same time, the hydrolysis of the remaining citrate ions in the solid obtained after the solid-liquid separation in the previous step is inhibited, which can further dissolve the sulfur in the sludge; then the mixed liquid-solid treated with alkali in the previous step is Separate the liquid, mix the obtained solid with water, add an appropriate amount of acid and citrate reagent, and stir thoroughly to further dissolve the sulfur, silicon and magnesium in the sludge, and achieve the purpose of further purifying the calcium fluoride in the sludge.
- the treatment method of the present invention can selectively remove impurities step by step according to the use or quality requirements of calcium fluoride, and effectively convert and separate the components in low-grade calcium fluoride-containing sludge.
- the treatment method of the present invention can reduce the dissolution of fluorine in the sludge and reduce the secondary pollution of fluorine while using calcium fluoride-containing sludge to produce calcium fluoride that meets the quality requirements of fluorite ore.
- the treatment method of the present invention has tolerant treatment conditions, uses reagents that are easily available, does not require expensive equipment investment, is low in cost, and is easy to promote.
- the treatment method of the present invention can effectively recover calcium fluoride-containing sludge, reduce the output of fluoride-containing sludge, and reduce the processing cost of solid waste residue during the treatment of fluoride-containing wastewater.
- This embodiment recycles calcium fluoride-containing sludge, which specifically includes the following steps:
- step (2) Add 0.2g/g dry sodium citrate dihydrate containing calcium fluoride sludge to the mixed solution obtained in step (1), add 30% hydrochloric acid to adjust the pH of the mixed solution to 6.5, and stir the reaction 50min for solid-liquid separation;
- step (3) Rinse the solid precipitate obtained in step (2) three times, then dry and pulverize to obtain the finished calcium fluoride product.
- This embodiment recycles calcium fluoride-containing sludge, which specifically includes the following steps:
- step (2) Add 0.033g/g dry calcium fluoride-containing sludge citric acid monohydrate to the mixed solution obtained in step (1), add 30% hydrochloric acid to adjust the pH of the mixed solution to 4.5, and stir for 50 minutes. , perform solid-liquid separation;
- step (3) Rinse the solid precipitate obtained in step (2) five times, then dry and pulverize to obtain the finished calcium fluoride product.
- This embodiment recycles calcium fluoride-containing sludge, which specifically includes the following steps:
- step (2) Add 0.067g/g dry calcium fluoride-containing sludge citric acid monohydrate to the first mixed solution obtained in step (1), add 30% hydrochloric acid to adjust the pH of the mixed solution to 4, and stir React for 50 minutes, perform solid-liquid separation, and obtain the first solid precipitation;
- step (3) Mix the first solid precipitate obtained in step (2) and water at a mass ratio of 1:10 to obtain a second mixed liquid;
- step (3) Add 40% sodium hydroxide solution to the second mixed solution obtained in step (3), adjust the pH of the mixed solution to 11, stir and react for 40 minutes, and perform solid-liquid separation to obtain a second solid precipitate;
- step (6) Add 0.033g/g dry calcium fluoride-containing sludge citric acid monohydrate to the third mixed solution obtained in step (5), add 30% hydrochloric acid to adjust the pH of the mixed solution to 2.5, and stir React for 50 minutes, perform solid-liquid separation, and obtain a third solid precipitate;
- step (7) Rinse the third solid precipitate obtained in step (6) five times, then dry and pulverize to obtain the finished calcium fluoride product.
- This embodiment recycles calcium fluoride-containing sludge, which specifically includes the following steps:
- step (2) Add 0.1g/g dry calcium fluoride-containing sludge citric acid monohydrate to the first mixed solution obtained in step (1), add 30% hydrochloric acid to adjust the pH of the mixed solution to 4, and stir React for 50 minutes, perform solid-liquid separation, and obtain the first solid precipitation;
- step (3) Mix the first solid precipitate obtained in step (2) and water at a mass ratio of 1:10 to obtain a second mixed liquid;
- step (3) Add 15% sodium carbonate solution to the second mixed solution obtained in step (3), adjust the pH of the mixed solution to 11, stir and react for 40 minutes, and perform solid-liquid separation to obtain a second solid precipitate;
- step (6) Add 0.03g/g dry calcium fluoride-containing sludge citric acid monohydrate to the third mixed solution obtained in step (5), add 30% hydrochloric acid to adjust the pH of the mixed solution to 2, and stir React for 50 minutes, perform solid-liquid separation, and obtain a third solid precipitate;
- step (7) Rinse the third solid precipitate obtained in step (6) five times, then dry and pulverize to obtain the finished calcium fluoride product.
- Comparative Example 1 (the only difference from Example 1 is that no citrate reagent is added)
- This embodiment recycles calcium fluoride-containing sludge, specifically including the following steps:
- step (2) Add 30% hydrochloric acid to the mixed solution obtained in step (1) to adjust the pH of the mixed solution to 6.5, stir and react for 50 minutes, and perform solid-liquid separation;
- step (3) Rinse the solid precipitate obtained in step (2) three times, then dry and pulverize to obtain the finished calcium fluoride product.
- This embodiment recycles calcium fluoride-containing sludge, which specifically includes the following steps:
- step (2) Add 0.1g/g dry calcium fluoride-containing sludge citric acid monohydrate to the mixed solution obtained in step (1), add 30% hydrochloric acid to adjust the pH of the mixed solution to 2.5, and stir for 50 minutes. , perform solid-liquid separation;
- step (3) Rinse the solid precipitate obtained in step (2) five times, then dry and pulverize to obtain the finished calcium fluoride product.
- the proportion of calcium fluoride dry basis in the solid precipitates from Examples 1 to 4 reaches more than 65%.
- it can be used as a substitute for calcium fluoride used in chemical industry, metallurgy, building materials, machinery and other industries upon request. Stone powder ore.
- the technical solution of Example 2 is selected to achieve a low F leaching rate and at the same time obtain a calcium fluoride product that meets the requirements, basically avoiding the calcium fluoride sludge purification process. secondary pollution of F; further, by adopting the technical solution of Example 3, a finished product of calcium fluoride with a purity higher than 85% can be obtained while reducing the leaching rate of F.
- This invention mainly uses the complexation of citrate ions and calcium ions to purify calcium fluoride. Since calcium fluoride has a certain solubility in acid, the pH should be controlled within a certain range when using citrate reagents and acid leaching impurities. , as in Example 2, when the pH is adjusted to 4.5, S, Si, and Mg are all leached more, while F is less leached.
- Example 1 the residual amount of Si after calcium fluoride-containing sludge treatment is basically unchanged. This is because the leaching of Si in the sludge is mainly related to the pH of the solution, so it is basically not leached under the weakly acidic conditions in Example 1. Leaching. In Example 2, although the citrate ion content is less than that in Example 1, the pH of the solution is lower, so more Si is leached.
- step (2) in Comparative Example 1 does not add citrate reagent. Under the same acidic conditions, there is a lack of complexing effect of citrate ions on calcium ions. S in the calcium fluoride-containing sludge It failed to be leached from the sludge without effective conversion, so the dry basis proportion of calcium fluoride in the sludge failed to reach 65%.
- Example 3 the addition of alkali treatment mixture in step (4) can reduce the leaching of F on the one hand, and on the other hand, in an alkaline environment, the hydrolysis of citrate ions is inhibited, which is beneficial to the leaching of S by citrate ions.
- Example 3 Compared with Example 3, there is no alkali addition process in step (4) in Comparative Example 2.
- the same dose of citrate reagent is directly added and acid is added to adjust the pH to 2.5.
- citric acid ionization is inhibited, the citrate ion content is reduced, and the complexing effect on calcium ions is weakened. Therefore, S in calcium fluoride-containing sludge is not effectively converted and cannot be leached from the sludge.
- lower pH will also make the leaching rate of F higher, and the dry basis proportion of calcium fluoride in the sludge cannot reach 85%.
- Example 4 the leaching rate of F is significantly higher than that of other examples. This is because the alkali used in step (4) is sodium carbonate solution, and calcium fluoride is converted into calcium carbonate with lower solubility during the stirring process, so that F More leaching.
Abstract
Disclosed in the present invention is a method for recycling a sludge containing calcium fluoride. The method comprises the following steps: mixing sludge containing calcium fluoride with water, then adding a first citrate reagent and a first acid liquid, and stirring same, followed by solid-liquid separation, so as to obtain a first solid. Preferably, the method further comprises the following steps: mixing the first solid with water, adding an alkali, and stirring same, followed by solid-liquid separation, so as to obtain a second solid; and mixing the second solid with water, adding a second citrate reagent and a second acid liquid, and stirring same, followed by solid-liquid separation, so as to obtain a finished calcium fluoride product. In the method, low-grade sludge containing calcium fluoride is used as a raw material, a citrate reagent is used in combination with an acid and an alkali, and calcium fluoride meeting the quality requirements of different industries is obtained by controlling the amount of the reagent and removing impurities, such that the secondary pollution of fluorine is reduced while the sludge containing calcium fluoride is effectively recycled.
Description
本发明属于固废处理的技术领域，具体涉及一种含氟化钙污泥资源化的方法。The invention belongs to the technical field of solid waste treatment, and specifically relates to a method for recycling calcium fluoride-containing sludge.
国内光伏和玻璃、电池回收等行业发展飞快，产业规模迅速扩大，但这些行业在生产的过程会产生大量高浓度的含氟废水。有效处理含氟废水的方法有超滤法、离子交换树脂法、电渗析法等，而从处理效果及处理成本等方面综合考虑，目前处理含氟废水最普遍的方法还是化学沉淀-混凝处理法，一般加入氯化钙或氢氧化钙形成沉淀，后续再进行絮凝处理。化学沉淀法产生的污泥量较大，污泥中常常包含有氟化钙、硅酸钙、硫酸钙以及某些金属的氢氧化物等成分。Domestic photovoltaic, glass, battery recycling and other industries are developing rapidly and the scale of the industry is expanding rapidly. However, the production process of these industries will produce a large amount of high-concentration fluorine-containing wastewater. Effective methods for treating fluoride-containing wastewater include ultrafiltration, ion exchange resin, electrodialysis, etc. Considering the treatment effect and cost, the most common method for treating fluoride-containing wastewater is chemical precipitation-coagulation treatment. Method, generally add calcium chloride or calcium hydroxide to form a precipitate, and then perform flocculation treatment. The chemical precipitation method produces a large amount of sludge, which often contains components such as calcium fluoride, calcium silicate, calcium sulfate, and hydroxides of certain metals.
氟化钙污泥属于工业废固，常规处理方法以填埋或焚烧为主。氟化钙具有低毒性，微溶于水，极易被植物吸收，并会污染土壤和地下水造成二次污染。填埋法处理能力有限，对填埋场的要求极高，同时也造成氟资源与土地资源的浪费。焚烧法处理含氟污泥过程中会产生有毒的含氟气体，同样会影响人体健康。氟化钙又称萤石，目前主要用于冶金、化工和建材等行业，属于不可再生资源。如今工业发展对氟化钙的需求日益增加，填埋或焚烧会使得氟化钙资源无法得到有效利用。Calcium fluoride sludge is industrial solid waste, and the conventional treatment methods are landfill or incineration. Calcium fluoride has low toxicity, is slightly soluble in water, is easily absorbed by plants, and will contaminate soil and groundwater causing secondary pollution. The landfill method has limited processing capacity and extremely high requirements for landfill sites. It also causes a waste of fluorine resources and land resources. The process of treating fluorine-containing sludge by incineration will produce toxic fluorine-containing gases, which will also affect human health. Calcium fluoride, also known as fluorspar, is currently mainly used in metallurgy, chemicals, building materials and other industries and is a non-renewable resource. Nowadays, industrial development has an increasing demand for calcium fluoride. Landfilling or incineration will prevent the effective utilization of calcium fluoride resources.
综上所述，寻求一种将氟化钙污泥资源化的方法，同时减少氟的二次污染，处理成本低，处理效率高的工艺方法是目前工业废固处理亟需解决的问题。To sum up, finding a method to recycle calcium fluoride sludge while reducing secondary pollution of fluorine, with low treatment cost and high treatment efficiency is an urgent problem that needs to be solved in the current industrial waste solid treatment.
发明内容Contents of the invention
本发明旨在至少解决上述现有技术中存在的技术问题之一。为此，本发明提出一种含氟化钙污泥资源化的方法，该方法能够有效提纯污泥中的氟化钙，且减少污泥中氟的损失。The present invention aims to solve at least one of the technical problems existing in the above-mentioned prior art. To this end, the present invention proposes a method for recycling calcium fluoride-containing sludge, which can effectively purify calcium fluoride in the sludge and reduce the loss of fluorine in the sludge.
根据本发明的一个方面，提出了一种含氟化钙污泥资源化的方法，包括以下步骤：According to one aspect of the present invention, a method for recycling calcium fluoride-containing sludge is proposed, which includes the following steps:
将含氟化钙污泥与水混合后加入第一柠檬酸根试剂和第一酸液，搅拌后固液分离，
得到第一固体。After mixing the calcium fluoride-containing sludge with water, the first citrate reagent and the first acid solution are added, and the solid-liquid separation is carried out after stirring. The first solid is obtained.
在本发明的一些优选的实施方式中，还包括以下步骤：In some preferred embodiments of the present invention, the following steps are also included:
将所述第一固体与水混合加入碱，搅拌后固液分离，得到第二固体；Mix the first solid with water and add alkali, and after stirring, the solid and liquid are separated to obtain the second solid;
将所述第二固体与水混合后加入第二柠檬酸根试剂和第二酸液，搅拌后固液分离，得到氟化钙成品。After the second solid is mixed with water, the second citrate reagent and the second acid liquid are added, and after stirring, the solid and liquid are separated to obtain the finished calcium fluoride product.
在本发明的一些实施方式中，所述含氟化钙污泥为碱性污泥，其中CaF2干基占比为45wt％-65wt％，S和Si、Mg干基占比均为1.5wt％-3wt％。In some embodiments of the present invention, the calcium fluoride-containing sludge is alkaline sludge, in which the proportion of CaF 2 on a dry basis is 45wt%-65wt%, and the proportions of S, Si, and Mg on a dry basis are all 1.5wt. %-3wt%.
在本发明的一些实施方式中，所述含氟化钙污泥、第一固体和第二固体各自与水混合的质量比独立为1：(10-20)。In some embodiments of the present invention, the mass ratio of each of the calcium fluoride-containing sludge, the first solid and the second solid mixed with water is independently 1: (10-20).
在本发明的一些实施方式中，所述第一柠檬酸根试剂和第二柠檬酸根试剂独立为柠檬酸、柠檬酸钠、柠檬酸二氢钠、柠檬酸钾或柠檬酸铵中的至少一种。In some embodiments of the present invention, the first citrate reagent and the second citrate reagent are independently at least one of citric acid, sodium citrate, sodium dihydrogen citrate, potassium citrate or ammonium citrate.
在本发明的一些实施方式中，所述第一酸液和第二酸液独立为盐酸、硝酸中的至少一种。In some embodiments of the present invention, the first acid liquid and the second acid liquid are independently at least one of hydrochloric acid and nitric acid.
在本发明的一些实施方式中，所述第一柠檬酸根试剂的加入量与所述含氟化钙污泥的质量比为(0.01-0.3)：1。In some embodiments of the present invention, the mass ratio of the added amount of the first citrate reagent to the calcium fluoride-containing sludge is (0.01-0.3):1.
在本发明的一些优选的实施方式中，所述第一柠檬酸根试剂的加入量与所述含氟化钙污泥的质量比为(0.03-0.25)：1。In some preferred embodiments of the present invention, the mass ratio of the added amount of the first citrate reagent to the calcium fluoride-containing sludge is (0.03-0.25):1.
在本发明的一些实施方式中，加入所述第一柠檬酸根试剂和所述第一酸液后得到的混合液的pH为2-7。In some embodiments of the present invention, the pH of the mixed solution obtained after adding the first citrate reagent and the first acid solution is 2-7.
在本发明的一些优选的实施方式中，加入所述第一柠檬酸根试剂和所述第一酸液后得到的混合液的pH为4-7。In some preferred embodiments of the present invention, the pH of the mixed solution obtained after adding the first citrate reagent and the first acid solution is 4-7.
在本发明的一些实施方式中，所述搅拌的时间为30-80min。In some embodiments of the present invention, the stirring time is 30-80 minutes.
在本发明的一些优选的实施方式中，所述搅拌的时间为40-60min。In some preferred embodiments of the present invention, the stirring time is 40-60 minutes.
在本发明的一些实施方式中，经第一柠檬酸根试剂和第一酸液处理后的混合液固液分离处理后，还包括对所述第一固体进行洗涤、烘干及粉碎操作，所述第一固体中CaF2干基占比≥65wt％，S的干基占比≤1.9wt％，Mg的干基占比≤0.3wt％。
In some embodiments of the present invention, after the solid-liquid separation of the mixed liquid treated with the first citrate reagent and the first acid liquid, the first solid is also washed, dried and pulverized, and the The dry basis ratio of CaF 2 in the first solid is ≥65wt%, the dry basis ratio of S is ≤1.9wt%, and the dry basis ratio of Mg is ≤0.3wt%.
在本发明的一些实施方式中，所述碱为氢氧化钠、氢氧化钾、氨水、碳酸钠或碳酸氢钠中的至少一种。In some embodiments of the invention, the base is at least one of sodium hydroxide, potassium hydroxide, ammonia, sodium carbonate or sodium bicarbonate.
在本发明的一些优选的实施方式中，所述碱为氢氧化钠、氢氧化钾或氨水中的至少一种。In some preferred embodiments of the present invention, the base is at least one of sodium hydroxide, potassium hydroxide or ammonia water.
在本发明的一些实施方式中，加入所述碱后得到的混合液的pH为8-13。In some embodiments of the present invention, the pH of the mixed solution obtained after adding the base is 8-13.
在本发明的一些优选的实施方式中，加入所述碱后得到的混合液的pH为9-12。In some preferred embodiments of the present invention, the pH of the mixed solution obtained after adding the base is 9-12.
在本发明的一些实施方式中，所述第二柠檬酸根试剂的加入量与所述含氟化钙污泥的质量比为(0.01-0.1)：1。In some embodiments of the present invention, the mass ratio of the added amount of the second citrate reagent to the calcium fluoride-containing sludge is (0.01-0.1):1.
在本发明的一些优选的实施方式中，所述第二柠檬酸根试剂的加入量与所述含氟化钙污泥的质量比为(0.01-0.05)：1。In some preferred embodiments of the present invention, the mass ratio of the added amount of the second citrate reagent to the calcium fluoride-containing sludge is (0.01-0.05):1.
在本发明的一些实施方式中，加入所述第二柠檬酸根试剂和所述第二酸液后得到的混合液的pH为1-5。In some embodiments of the present invention, the pH of the mixed solution obtained after adding the second citrate reagent and the second acid solution is 1-5.
在本发明的一些优选的实施方式中，加入所述第二柠檬酸根试剂和所述第二酸液后得到的混合液的pH为2-4。In some preferred embodiments of the present invention, the pH of the mixed solution obtained after adding the second citrate reagent and the second acid solution is 2-4.
在本发明的一些实施方式中，经第二柠檬酸根试剂和第二酸液处理后的混合液固液分离处理后，还包括对所得固体沉淀进行洗涤、烘干及粉碎，得到氟化钙成品。进一步地，所述洗涤为淋洗固体3-5次。In some embodiments of the present invention, after the solid-liquid separation treatment of the mixed liquid treated with the second citrate reagent and the second acid liquid, the solid precipitate obtained is washed, dried and pulverized to obtain the finished calcium fluoride product. . Further, the washing involves rinsing the solid 3-5 times.
在本发明的一些实施方式中，所述氟化钙成品中CaF2干基占比≥85wt％，S的干基占比≤1.9wt％，Si的干基占比≤1.5wt％，Mg的干基占比≤0.1wt％。In some embodiments of the present invention, the dry basis ratio of CaF 2 in the finished calcium fluoride product is ≥85wt%, the dry basis ratio of S is ≤1.9wt%, the dry basis ratio of Si is ≤1.5wt%, and the dry basis ratio of Mg is ≤1.5wt%. Dry basis proportion ≤ 0.1wt%.
根据本发明的一种优选的实施方式，至少具有以下有益效果：According to a preferred embodiment of the present invention, it has at least the following beneficial effects:
1、本发明主要应用柠檬酸根离子与钙离子的络合作用进行氟化钙的提纯，往含氟化钙污泥与水的混合液中加入适量的酸和柠檬酸根试剂，酸能除去污泥中大部分含镁沉淀，同时使硅部分溶出；柠檬酸根离子通过与钙离子络合使硫部分溶出，而氟化钙溶解度较低，氟溶出较少。固液分离后，得到的氟化钙干基占比达到65％以上，已可以替代化工、冶金、建材及机械等行业所使用的萤石粉矿；1. The present invention mainly uses the complexation of citrate ions and calcium ions to purify calcium fluoride. Add an appropriate amount of acid and citrate reagent to the mixture of calcium fluoride-containing sludge and water. The acid can remove the sludge. Most of them contain magnesium precipitates, which also partially dissolves silicon; citrate ions partially dissolve sulfur through complexing with calcium ions, while calcium fluoride has low solubility and less fluorine dissolves. After solid-liquid separation, the obtained calcium fluoride dry basis accounts for more than 65%, which can replace fluorspar powder ore used in chemical industry, metallurgy, building materials, machinery and other industries;
优选地，将上一步固液分离后的固体与水混合，加入适量的碱后充分搅拌，碱性环
境抑制了氟的溶出，同时上一步固液分离后得到的固体中残留的柠檬酸根离子的水解被抑制，能将污泥中的硫进一步溶出；再将上一步加碱处理过后的混合液固液分离，得到的固体与水混合，加入适量的酸和柠檬酸根试剂，充分搅拌，能使污泥中的硫、硅和镁进一步溶出，达到进一步提纯污泥中氟化钙的目的。Preferably, the solid after solid-liquid separation in the previous step is mixed with water, an appropriate amount of alkali is added and stirred thoroughly, and the alkaline ring The environment inhibits the dissolution of fluorine, and at the same time, the hydrolysis of the remaining citrate ions in the solid obtained after the solid-liquid separation in the previous step is inhibited, which can further dissolve the sulfur in the sludge; then the mixed liquid-solid treated with alkali in the previous step is Separate the liquid, mix the obtained solid with water, add an appropriate amount of acid and citrate reagent, and stir thoroughly to further dissolve the sulfur, silicon and magnesium in the sludge, and achieve the purpose of further purifying the calcium fluoride in the sludge.
2、本发明的处理方法，可根据氟化钙的用途或质量要求选择性地进行分步除杂，对低品位的含氟化钙污泥中的成分有效地进行转换和分离。2. The treatment method of the present invention can selectively remove impurities step by step according to the use or quality requirements of calcium fluoride, and effectively convert and separate the components in low-grade calcium fluoride-containing sludge.
3、本发明的处理方法，在使用含氟化钙污泥生产符合萤石矿质量要求的氟化钙的同时，可减少污泥中氟的溶出，减少氟的二次污染。3. The treatment method of the present invention can reduce the dissolution of fluorine in the sludge and reduce the secondary pollution of fluorine while using calcium fluoride-containing sludge to produce calcium fluoride that meets the quality requirements of fluorite ore.
4、本发明的处理方法，处理条件宽容，使用的试剂常规易得，无需昂贵的设备投入，成本低廉，易于推广。4. The treatment method of the present invention has tolerant treatment conditions, uses reagents that are easily available, does not require expensive equipment investment, is low in cost, and is easy to promote.
5、本发明的处理方法，可对含氟化钙污泥进行有效回收，使含氟污泥产量减少，降低了含氟废水处理过程中固废渣的处理成本。5. The treatment method of the present invention can effectively recover calcium fluoride-containing sludge, reduce the output of fluoride-containing sludge, and reduce the processing cost of solid waste residue during the treatment of fluoride-containing wastewater.
以下将结合实施例对本发明的构思及产生的技术效果进行清楚、完整地描述，以充分地理解本发明的目的、特征和效果。显然，所描述的实施例只是本发明的一部分实施例，而不是全部实施例，基于本发明的实施例，本领域的技术人员在不付出创造性劳动的前提下所获得的其他实施例，均属于本发明保护的范围。The concept of the present invention and the technical effects produced will be clearly and completely described below with reference to the embodiments, so as to fully understand the purpose, features and effects of the present invention. Obviously, the described embodiments are only some of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, other embodiments obtained by those skilled in the art without exerting creative efforts are all protection scope of the present invention.
实施例1Example 1
本实施例对含氟化钙污泥进行回收处理，具体包括如下步骤：This embodiment recycles calcium fluoride-containing sludge, which specifically includes the following steps:
(1)取30g烘干后的含氟化钙污泥，与水以质量比1：20的比例进行混合，得到混合液；(1) Take 30g of dried calcium fluoride-containing sludge and mix it with water at a mass ratio of 1:20 to obtain a mixed liquid;
(2)向步骤(1)得到的所述混合液中依次加入0.2g/g干含氟化钙污泥的二水柠檬酸钠，加入30％的盐酸将混合液pH调至6.5，搅拌反应50min，进行固液分离；(2) Add 0.2g/g dry sodium citrate dihydrate containing calcium fluoride sludge to the mixed solution obtained in step (1), add 30% hydrochloric acid to adjust the pH of the mixed solution to 6.5, and stir the reaction 50min for solid-liquid separation;
(3)将步骤(2)得到的固体沉淀淋洗3次，然后烘干，粉碎，得到氟化钙成品。(3) Rinse the solid precipitate obtained in step (2) three times, then dry and pulverize to obtain the finished calcium fluoride product.
实施例2Example 2
本实施例对含氟化钙污泥进行回收处理，具体包括如下步骤：
This embodiment recycles calcium fluoride-containing sludge, which specifically includes the following steps:
(1)取30g烘干后的含氟化钙污泥，与水以质量比1：20的比例进行混合，得到混合液；(1) Take 30g of dried calcium fluoride-containing sludge and mix it with water at a mass ratio of 1:20 to obtain a mixed liquid;
(2)向步骤(1)得到的所述混合液中依次加入0.033g/g干含氟化钙污泥的一水柠檬酸，加入30％的盐酸将混合液pH调至4.5，搅拌反应50min，进行固液分离；(2) Add 0.033g/g dry calcium fluoride-containing sludge citric acid monohydrate to the mixed solution obtained in step (1), add 30% hydrochloric acid to adjust the pH of the mixed solution to 4.5, and stir for 50 minutes. , perform solid-liquid separation;
(3)将步骤(2)得到的固体沉淀淋洗5次，然后烘干，粉碎，得到氟化钙成品。(3) Rinse the solid precipitate obtained in step (2) five times, then dry and pulverize to obtain the finished calcium fluoride product.
实施例3Example 3
本实施例对含氟化钙污泥进行回收处理，具体包括如下步骤：This embodiment recycles calcium fluoride-containing sludge, which specifically includes the following steps:
(1)取30g烘干后的含氟化钙污泥，与水以质量比1：10的比例进行混合，得到第一混合液；(1) Take 30g of dried calcium fluoride-containing sludge and mix it with water at a mass ratio of 1:10 to obtain the first mixed liquid;
(2)向步骤(1)得到的所述第一混合液中依次加入0.067g/g干含氟化钙污泥的一水柠檬酸，加入30％的盐酸将混合液pH调至4，搅拌反应50min，进行固液分离，得到第一固体沉淀；(2) Add 0.067g/g dry calcium fluoride-containing sludge citric acid monohydrate to the first mixed solution obtained in step (1), add 30% hydrochloric acid to adjust the pH of the mixed solution to 4, and stir React for 50 minutes, perform solid-liquid separation, and obtain the first solid precipitation;
(3)将步骤(2)得到的所述第一固体沉淀与水以质量比1：10的比例混合，得到第二混合液；(3) Mix the first solid precipitate obtained in step (2) and water at a mass ratio of 1:10 to obtain a second mixed liquid;
(4)向步骤(3)得到的所述第二混合液中加入40％的氢氧化钠溶液，将混合液pH调至11，搅拌反应40min，进行固液分离得到第二固体沉淀；(4) Add 40% sodium hydroxide solution to the second mixed solution obtained in step (3), adjust the pH of the mixed solution to 11, stir and react for 40 minutes, and perform solid-liquid separation to obtain a second solid precipitate;
(5)将步骤(4)得到的所述第二固体沉淀与水以质量比1：10的比例混合，得到第三混合液；(5) Mix the second solid precipitate obtained in step (4) with water in a mass ratio of 1:10 to obtain a third mixed liquid;
(6)向步骤(5)得到的所述第三混合液中依次加入0.033g/g干含氟化钙污泥的一水柠檬酸，加入30％的盐酸将混合液pH调至2.5，搅拌反应50min，进行固液分离，得到第三固体沉淀；(6) Add 0.033g/g dry calcium fluoride-containing sludge citric acid monohydrate to the third mixed solution obtained in step (5), add 30% hydrochloric acid to adjust the pH of the mixed solution to 2.5, and stir React for 50 minutes, perform solid-liquid separation, and obtain a third solid precipitate;
(7)将步骤(6)得到的所述第三固体沉淀淋洗5次，然后烘干，粉碎，得到氟化钙成品。(7) Rinse the third solid precipitate obtained in step (6) five times, then dry and pulverize to obtain the finished calcium fluoride product.
实施例4Example 4
本实施例对含氟化钙污泥进行回收处理，具体包括如下步骤：This embodiment recycles calcium fluoride-containing sludge, which specifically includes the following steps:
(1)取30g烘干后的含氟化钙污泥，与水以质量比1：10的比例进行混合，得到
第一混合液；(1) Take 30g of dried calcium fluoride-containing sludge and mix it with water at a mass ratio of 1:10 to obtain first mixture;
(2)向步骤(1)得到的所述第一混合液中依次加入0.1g/g干含氟化钙污泥的一水柠檬酸，加入30％的盐酸将混合液pH调至4，搅拌反应50min，进行固液分离，得到第一固体沉淀；(2) Add 0.1g/g dry calcium fluoride-containing sludge citric acid monohydrate to the first mixed solution obtained in step (1), add 30% hydrochloric acid to adjust the pH of the mixed solution to 4, and stir React for 50 minutes, perform solid-liquid separation, and obtain the first solid precipitation;
(3)将步骤(2)得到的所述第一固体沉淀与水以质量比1：10的比例混合，得到第二混合液；(3) Mix the first solid precipitate obtained in step (2) and water at a mass ratio of 1:10 to obtain a second mixed liquid;
(4)向步骤(3)得到的所述第二混合液中加入15％的碳酸钠溶液，将混合液pH调至11，搅拌反应40min，进行固液分离得到第二固体沉淀；(4) Add 15% sodium carbonate solution to the second mixed solution obtained in step (3), adjust the pH of the mixed solution to 11, stir and react for 40 minutes, and perform solid-liquid separation to obtain a second solid precipitate;
(5)将步骤(4)得到的所述第二固体沉淀与水以质量比1：10的比例混合，得到第三混合液；(5) Mix the second solid precipitate obtained in step (4) with water in a mass ratio of 1:10 to obtain a third mixed liquid;
(6)向步骤(5)得到的所述第三混合液中依次加入0.03g/g干含氟化钙污泥的一水柠檬酸，加入30％的盐酸将混合液pH调至2，搅拌反应50min，进行固液分离，得到第三固体沉淀；(6) Add 0.03g/g dry calcium fluoride-containing sludge citric acid monohydrate to the third mixed solution obtained in step (5), add 30% hydrochloric acid to adjust the pH of the mixed solution to 2, and stir React for 50 minutes, perform solid-liquid separation, and obtain a third solid precipitate;
(7)将步骤(6)得到的所述第三固体沉淀淋洗5次，然后烘干，粉碎，得到氟化钙成品。(7) Rinse the third solid precipitate obtained in step (6) five times, then dry and pulverize to obtain the finished calcium fluoride product.
对比例1(与实施例1的区别仅在于没有加入柠檬酸根试剂)Comparative Example 1 (the only difference from Example 1 is that no citrate reagent is added)
本实施例对含氟化钙污泥进行回收处理，具体包括如下步骤：This embodiment recycles calcium fluoride-containing sludge, specifically including the following steps:
(1)取30g烘干后的含氟化钙污泥，与水以质量比1：20的比例进行混合，得到混合液；(1) Take 30g of dried calcium fluoride-containing sludge and mix it with water at a mass ratio of 1:20 to obtain a mixed liquid;
(2)向步骤(1)得到的所述混合液中加入30％的盐酸将混合液pH调至6.5，搅拌反应50min，进行固液分离；(2) Add 30% hydrochloric acid to the mixed solution obtained in step (1) to adjust the pH of the mixed solution to 6.5, stir and react for 50 minutes, and perform solid-liquid separation;
(3)将步骤(2)得到的固体沉淀淋洗3次，然后烘干，粉碎，得到氟化钙成品。(3) Rinse the solid precipitate obtained in step (2) three times, then dry and pulverize to obtain the finished calcium fluoride product.
对比例2(与实施例3的区别仅在于缺少加碱处理的步骤)Comparative Example 2 (the only difference from Example 3 is the lack of alkali addition step)
本实施例对含氟化钙污泥进行回收处理，具体包括如下步骤：This embodiment recycles calcium fluoride-containing sludge, which specifically includes the following steps:
(1)取30g烘干后的含氟化钙污泥，与水以质量比1：10的比例进行混合，得到混合液；
(1) Take 30g of dried calcium fluoride-containing sludge and mix it with water at a mass ratio of 1:10 to obtain a mixed liquid;
(2)向步骤(1)得到的所述混合液中依次加入0.1g/g干含氟化钙污泥的一水柠檬酸，加入30％的盐酸将混合液pH调至2.5，搅拌反应50min，进行固液分离；(2) Add 0.1g/g dry calcium fluoride-containing sludge citric acid monohydrate to the mixed solution obtained in step (1), add 30% hydrochloric acid to adjust the pH of the mixed solution to 2.5, and stir for 50 minutes. , perform solid-liquid separation;
(3)将步骤(2)得到的固体沉淀淋洗5次，然后烘干，粉碎，得到氟化钙成品。(3) Rinse the solid precipitate obtained in step (2) five times, then dry and pulverize to obtain the finished calcium fluoride product.
试验例Test example
分别检测实施例1-4及对比例1-2中含氟化钙污泥处理前后主要成分占比，检测结果如表1所示。The proportions of the main components in the calcium fluoride-containing sludge before and after treatment in Examples 1-4 and Comparative Examples 1-2 were respectively detected. The test results are shown in Table 1.
表1含氟化钙污泥处理前后主要成分干基占比
Table 1 Dry basis proportion of main components before and after treatment of calcium fluoride-containing sludge
Table 1 Dry basis proportion of main components before and after treatment of calcium fluoride-containing sludge
实施例1至实施例4的固体沉淀中氟化钙干基占比达到65％以上，依照YB/T5217-2005标准，可根据要求，替代适用于化工、冶金、建材及机械等行业使用的萤石粉矿。例如，在氟化钙纯度要求不高于75％时，选用实施例2的技术方案，使F浸出率较低的同时得到符合要求的氟化钙成品，基本避免了氟化钙污泥提纯过程中F的二次污染；进一步地，选用实施例3的技术方案，可以在减少F浸出率的同时得到纯度高于85％的氟化钙成品。The proportion of calcium fluoride dry basis in the solid precipitates from Examples 1 to 4 reaches more than 65%. According to the YB/T5217-2005 standard, it can be used as a substitute for calcium fluoride used in chemical industry, metallurgy, building materials, machinery and other industries upon request. Stone powder ore. For example, when the purity of calcium fluoride is required to be no higher than 75%, the technical solution of Example 2 is selected to achieve a low F leaching rate and at the same time obtain a calcium fluoride product that meets the requirements, basically avoiding the calcium fluoride sludge purification process. secondary pollution of F; further, by adopting the technical solution of Example 3, a finished product of calcium fluoride with a purity higher than 85% can be obtained while reducing the leaching rate of F.
本发明主要应用柠檬酸根离子与钙离子的络合作用进行氟化钙的提纯，由于氟化钙在酸中有一定的溶解度，在使用柠檬酸根试剂和酸浸出杂质时应控制pH在一定的范围，如实施例2中，pH调至4.5时，S、Si、Mg均有较多浸出，而F的浸出较少。This invention mainly uses the complexation of citrate ions and calcium ions to purify calcium fluoride. Since calcium fluoride has a certain solubility in acid, the pH should be controlled within a certain range when using citrate reagents and acid leaching impurities. , as in Example 2, when the pH is adjusted to 4.5, S, Si, and Mg are all leached more, while F is less leached.
实施例1中，含氟化钙污泥处理后Si的残留量基本未变，这是由于污泥中Si的浸出主要与溶液pH有关，因此在实施例1中的弱酸性条件下基本未被浸出。而在实施例2中，虽然柠檬酸根离子含量较实施例1少，但溶液pH较低，因而Si浸出较多。
In Example 1, the residual amount of Si after calcium fluoride-containing sludge treatment is basically unchanged. This is because the leaching of Si in the sludge is mainly related to the pH of the solution, so it is basically not leached under the weakly acidic conditions in Example 1. Leaching. In Example 2, although the citrate ion content is less than that in Example 1, the pH of the solution is lower, so more Si is leached.
相比于实施例1，对比例1中的步骤(2)未添加柠檬酸根试剂，在相同的酸性条件下，缺少柠檬酸根离子对钙离子的络合作用，含氟化钙污泥中的S未进行有效转化而未能从污泥中浸出，因而污泥中的氟化钙干基占比未能达到65％。Compared with Example 1, step (2) in Comparative Example 1 does not add citrate reagent. Under the same acidic conditions, there is a lack of complexing effect of citrate ions on calcium ions. S in the calcium fluoride-containing sludge It failed to be leached from the sludge without effective conversion, so the dry basis proportion of calcium fluoride in the sludge failed to reach 65%.
实施例3中，步骤(4)加入碱处理混合液，一方面可以减少F的浸出，另一方面在碱性环境下，柠檬酸根离子的水解被抑制，有利于柠檬酸根离子对S的浸出。In Example 3, the addition of alkali treatment mixture in step (4) can reduce the leaching of F on the one hand, and on the other hand, in an alkaline environment, the hydrolysis of citrate ions is inhibited, which is beneficial to the leaching of S by citrate ions.
相比于实施例3，对比例2中无步骤(4)的加碱过程，直接添加相同剂量的柠檬酸根试剂并加酸将pH调至2.5。pH较低时，柠檬酸电离被抑制，柠檬酸根离子含量减少，对钙离子的络合作用减弱，因此含氟化钙污泥中的S未进行有效转化而未能从污泥中浸出。同时，较低的pH也会使得F的浸出率更高，污泥中的氟化钙干基占比未能达到85％。Compared with Example 3, there is no alkali addition process in step (4) in Comparative Example 2. The same dose of citrate reagent is directly added and acid is added to adjust the pH to 2.5. When the pH is low, citric acid ionization is inhibited, the citrate ion content is reduced, and the complexing effect on calcium ions is weakened. Therefore, S in calcium fluoride-containing sludge is not effectively converted and cannot be leached from the sludge. At the same time, lower pH will also make the leaching rate of F higher, and the dry basis proportion of calcium fluoride in the sludge cannot reach 85%.
实施例4中，F的浸出率明显高于其他实施例，这是由于步骤(4)所使用的碱为碳酸钠溶液，搅拌过程中氟化钙转化为溶解度更低的碳酸钙，从而使F较多的浸出。In Example 4, the leaching rate of F is significantly higher than that of other examples. This is because the alkali used in step (4) is sodium carbonate solution, and calcium fluoride is converted into calcium carbonate with lower solubility during the stirring process, so that F More leaching.
上面结合表格对本发明实施例作了详细说明，但是本发明不限于上述实施例，在所属技术领域普通技术人员所具备的知识范围内，还可以在不脱离本发明宗旨的前提下作出各种变化。此外，在不冲突的情况下，本发明的实施例及实施例中的特征可以相互组合。
The embodiments of the present invention are described in detail above in conjunction with tables. However, the present invention is not limited to the above embodiments. Various changes can be made within the knowledge scope of those of ordinary skill in the art without departing from the purpose of the present invention. . In addition, the embodiments of the present invention and the features in the embodiments may be combined with each other without conflict.
Claims (10)
- 一种含氟化钙污泥资源化的方法，其特征在于，包括以下步骤：A method for recycling calcium fluoride-containing sludge, which is characterized by including the following steps:将含氟化钙污泥与水混合后加入第一柠檬酸根试剂和第一酸液，搅拌后固液分离，得到第一固体。After mixing the calcium fluoride-containing sludge with water, the first citrate reagent and the first acid liquid are added, and after stirring, the solid-liquid separation is performed to obtain the first solid.
- 根据权利要求1所述的一种含氟化钙污泥资源化的方法，其特征在于，还包括以下步骤：A method for recycling calcium fluoride-containing sludge according to claim 1, further comprising the following steps:将所述第一固体与水混合加入碱，搅拌后固液分离，得到第二固体；Mix the first solid with water and add alkali, and after stirring, the solid and liquid are separated to obtain the second solid;将所述第二固体与水混合后加入第二柠檬酸根试剂和第二酸液，搅拌后固液分离，得到氟化钙成品。After the second solid is mixed with water, the second citrate reagent and the second acid liquid are added, and after stirring, the solid and liquid are separated to obtain the finished calcium fluoride product.
- 根据权利要求1所述的含氟化钙污泥资源化的方法，其特征在于，所述第一柠檬酸根试剂的加入量与所述含氟化钙污泥的质量比为(0.01-0.3)：1。The method for recycling calcium fluoride-containing sludge according to claim 1, characterized in that the mass ratio of the added amount of the first citrate reagent to the calcium fluoride-containing sludge is (0.01-0.3) :1.
- 根据权利要求1所述的含氟化钙污泥资源化的方法，其特征在于，加入所述第一柠檬酸根试剂和所述第一酸液后得到的混合液的pH为2-7。The method for recycling calcium fluoride-containing sludge according to claim 1, characterized in that the pH of the mixed liquid obtained after adding the first citrate reagent and the first acid liquid is 2-7.
- 根据权利要求2所述的含氟化钙污泥资源化的方法，其特征在于，所述第一柠檬酸根试剂和第二柠檬酸根试剂独立为柠檬酸、柠檬酸钠、柠檬酸二氢钠、柠檬酸钾或柠檬酸铵中的至少一种。The method for recycling calcium fluoride-containing sludge according to claim 2, wherein the first citrate reagent and the second citrate reagent are independently citric acid, sodium citrate, sodium dihydrogen citrate, At least one of potassium citrate or ammonium citrate.
- 根据权利要求2所述的含氟化钙污泥资源化的方法，其特征在于，所述的第一酸液和第二酸液独立为盐酸及硝酸中的至少一种。The method for recycling calcium fluoride-containing sludge according to claim 2, characterized in that the first acid liquid and the second acid liquid are independently at least one of hydrochloric acid and nitric acid.
- 根据权利要求2所述的含氟化钙污泥资源化的方法，其特征在于，所述碱为氢氧化钠、氢氧化钾、氨水、碳酸钠或碳酸氢钠中的至少一种。The method for recycling calcium fluoride-containing sludge according to claim 2, characterized in that the alkali is at least one of sodium hydroxide, potassium hydroxide, ammonia water, sodium carbonate or sodium bicarbonate.
- 根据权利要求2所述的含氟化钙污泥资源化的方法，其特征在于，加入所述碱后得到的混合液的pH为8-13。The method for recycling calcium fluoride-containing sludge according to claim 2, characterized in that the pH of the mixed liquid obtained after adding the alkali is 8-13.
- 根据权利要求2所述的含氟化钙污泥资源化的方法，其特征在于，所述第二柠檬酸根试剂的加入量与所述含氟化钙污泥的质量比为(0.01-0.1)：1。The method for recycling calcium fluoride-containing sludge according to claim 2, characterized in that the mass ratio of the added amount of the second citrate reagent to the calcium fluoride-containing sludge is (0.01-0.1) :1.
- 根据权利要求2所述的含氟化钙污泥资源化的方法，其特征在于，加入所述第二柠檬酸根试剂和所述第二酸液后得到的混合液的pH为1-5。 The method for recycling calcium fluoride-containing sludge according to claim 2, characterized in that the pH of the mixed liquid obtained after adding the second citrate reagent and the second acid liquid is 1-5.
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