CN115626617A - Filtering and impurity removing method for ammonium monohydrogen phosphate or ammonium dihydrogen phosphate - Google Patents
Filtering and impurity removing method for ammonium monohydrogen phosphate or ammonium dihydrogen phosphate Download PDFInfo
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- CN115626617A CN115626617A CN202211356003.XA CN202211356003A CN115626617A CN 115626617 A CN115626617 A CN 115626617A CN 202211356003 A CN202211356003 A CN 202211356003A CN 115626617 A CN115626617 A CN 115626617A
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- ammonium
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- phosphate
- dihydrogen phosphate
- ammonium dihydrogen
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- LFVGISIMTYGQHF-UHFFFAOYSA-N ammonium dihydrogen phosphate Chemical compound [NH4+].OP(O)([O-])=O LFVGISIMTYGQHF-UHFFFAOYSA-N 0.000 title claims abstract description 204
- 229910000387 ammonium dihydrogen phosphate Inorganic materials 0.000 title claims abstract description 204
- 235000019837 monoammonium phosphate Nutrition 0.000 title claims abstract description 204
- 238000001914 filtration Methods 0.000 title claims abstract description 76
- 239000012535 impurity Substances 0.000 title claims abstract description 66
- MNNHAPBLZZVQHP-UHFFFAOYSA-N diammonium hydrogen phosphate Chemical compound [NH4+].[NH4+].OP([O-])([O-])=O MNNHAPBLZZVQHP-UHFFFAOYSA-N 0.000 title claims abstract description 50
- 229910000388 diammonium phosphate Inorganic materials 0.000 title claims abstract description 47
- 235000019838 diammonium phosphate Nutrition 0.000 title claims abstract description 47
- 238000000034 method Methods 0.000 title claims abstract description 39
- 239000011790 ferrous sulphate Substances 0.000 claims abstract description 66
- 235000003891 ferrous sulphate Nutrition 0.000 claims abstract description 66
- BAUYGSIQEAFULO-UHFFFAOYSA-L iron(2+) sulfate (anhydrous) Chemical compound [Fe+2].[O-]S([O-])(=O)=O BAUYGSIQEAFULO-UHFFFAOYSA-L 0.000 claims abstract description 66
- 229910000359 iron(II) sulfate Inorganic materials 0.000 claims abstract description 66
- 239000004744 fabric Substances 0.000 claims abstract description 39
- 239000002245 particle Substances 0.000 claims abstract description 25
- 238000006243 chemical reaction Methods 0.000 claims abstract description 11
- 238000003756 stirring Methods 0.000 claims description 83
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Chemical compound O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 70
- 239000008367 deionised water Substances 0.000 claims description 49
- 229910021641 deionized water Inorganic materials 0.000 claims description 49
- 238000000967 suction filtration Methods 0.000 claims description 48
- VHUUQVKOLVNVRT-UHFFFAOYSA-N Ammonium hydroxide Chemical compound [NH4+].[OH-] VHUUQVKOLVNVRT-UHFFFAOYSA-N 0.000 claims description 31
- 235000011114 ammonium hydroxide Nutrition 0.000 claims description 31
- 238000005406 washing Methods 0.000 claims description 25
- 230000035699 permeability Effects 0.000 claims description 23
- 230000007935 neutral effect Effects 0.000 claims description 20
- QGZKDVFQNNGYKY-UHFFFAOYSA-O Ammonium Chemical compound [NH4+] QGZKDVFQNNGYKY-UHFFFAOYSA-O 0.000 claims description 18
- 229940116007 ferrous phosphate Drugs 0.000 claims description 18
- 229910000155 iron(II) phosphate Inorganic materials 0.000 claims description 18
- SDEKDNPYZOERBP-UHFFFAOYSA-H iron(ii) phosphate Chemical compound [Fe+2].[Fe+2].[Fe+2].[O-]P([O-])([O-])=O.[O-]P([O-])([O-])=O SDEKDNPYZOERBP-UHFFFAOYSA-H 0.000 claims description 18
- 238000002156 mixing Methods 0.000 claims description 9
- 239000007788 liquid Substances 0.000 claims description 8
- 239000012452 mother liquor Substances 0.000 claims description 6
- 239000002904 solvent Substances 0.000 claims description 5
- ATRRKUHOCOJYRX-UHFFFAOYSA-N Ammonium bicarbonate Chemical compound [NH4+].OC([O-])=O ATRRKUHOCOJYRX-UHFFFAOYSA-N 0.000 claims description 2
- 229910000013 Ammonium bicarbonate Inorganic materials 0.000 claims description 2
- 235000012538 ammonium bicarbonate Nutrition 0.000 claims description 2
- 239000001099 ammonium carbonate Substances 0.000 claims description 2
- 239000003513 alkali Substances 0.000 claims 1
- 230000008569 process Effects 0.000 abstract description 5
- 239000011148 porous material Substances 0.000 abstract description 4
- 239000004254 Ammonium phosphate Substances 0.000 abstract description 3
- CWYNVVGOOAEACU-UHFFFAOYSA-N Fe2+ Chemical compound [Fe+2] CWYNVVGOOAEACU-UHFFFAOYSA-N 0.000 abstract description 3
- 229910000148 ammonium phosphate Inorganic materials 0.000 abstract description 3
- 235000019289 ammonium phosphates Nutrition 0.000 abstract description 3
- 238000004140 cleaning Methods 0.000 abstract description 2
- 239000000463 material Substances 0.000 abstract description 2
- 239000000243 solution Substances 0.000 description 188
- 239000006012 monoammonium phosphate Substances 0.000 description 126
- 238000005303 weighing Methods 0.000 description 52
- WBJZTOZJJYAKHQ-UHFFFAOYSA-K iron(3+) phosphate Chemical compound [Fe+3].[O-]P([O-])([O-])=O WBJZTOZJJYAKHQ-UHFFFAOYSA-K 0.000 description 31
- 239000011259 mixed solution Substances 0.000 description 25
- 229910000398 iron phosphate Inorganic materials 0.000 description 23
- 239000000706 filtrate Substances 0.000 description 20
- NBIIXXVUZAFLBC-UHFFFAOYSA-N Phosphoric acid Chemical compound OP(O)(O)=O NBIIXXVUZAFLBC-UHFFFAOYSA-N 0.000 description 14
- 230000000052 comparative effect Effects 0.000 description 12
- 238000009736 wetting Methods 0.000 description 9
- MHAJPDPJQMAIIY-UHFFFAOYSA-N Hydrogen peroxide Chemical compound OO MHAJPDPJQMAIIY-UHFFFAOYSA-N 0.000 description 8
- 239000000203 mixture Substances 0.000 description 8
- 239000005955 Ferric phosphate Substances 0.000 description 7
- 229910000147 aluminium phosphate Inorganic materials 0.000 description 7
- 229940032958 ferric phosphate Drugs 0.000 description 7
- 229910000399 iron(III) phosphate Inorganic materials 0.000 description 7
- 238000002360 preparation method Methods 0.000 description 6
- VEXZGXHMUGYJMC-UHFFFAOYSA-M Chloride anion Chemical compound [Cl-] VEXZGXHMUGYJMC-UHFFFAOYSA-M 0.000 description 5
- 229910021578 Iron(III) chloride Inorganic materials 0.000 description 5
- RBTARNINKXHZNM-UHFFFAOYSA-K iron trichloride Chemical compound Cl[Fe](Cl)Cl RBTARNINKXHZNM-UHFFFAOYSA-K 0.000 description 5
- 229920002401 polyacrylamide Polymers 0.000 description 5
- 239000000047 product Substances 0.000 description 5
- 230000000694 effects Effects 0.000 description 4
- 238000011049 filling Methods 0.000 description 4
- 238000012360 testing method Methods 0.000 description 4
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 3
- 230000032683 aging Effects 0.000 description 3
- 238000001354 calcination Methods 0.000 description 3
- 238000002474 experimental method Methods 0.000 description 3
- 239000012065 filter cake Substances 0.000 description 3
- 239000008394 flocculating agent Substances 0.000 description 3
- 238000010438 heat treatment Methods 0.000 description 3
- 230000006872 improvement Effects 0.000 description 3
- 238000004519 manufacturing process Methods 0.000 description 3
- 239000002244 precipitate Substances 0.000 description 3
- OYPRJOBELJOOCE-UHFFFAOYSA-N Calcium Chemical compound [Ca] OYPRJOBELJOOCE-UHFFFAOYSA-N 0.000 description 2
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 description 2
- 230000003321 amplification Effects 0.000 description 2
- 238000004458 analytical method Methods 0.000 description 2
- 239000003674 animal food additive Substances 0.000 description 2
- 229910052791 calcium Inorganic materials 0.000 description 2
- 239000011575 calcium Substances 0.000 description 2
- 239000010406 cathode material Substances 0.000 description 2
- 238000005202 decontamination Methods 0.000 description 2
- 238000011161 development Methods 0.000 description 2
- 230000018109 developmental process Effects 0.000 description 2
- 239000003814 drug Substances 0.000 description 2
- 239000003337 fertilizer Substances 0.000 description 2
- 239000003063 flame retardant Substances 0.000 description 2
- -1 fluoride ions Chemical class 0.000 description 2
- 238000009776 industrial production Methods 0.000 description 2
- GELKBWJHTRAYNV-UHFFFAOYSA-K lithium iron phosphate Chemical compound [Li+].[Fe+2].[O-]P([O-])([O-])=O GELKBWJHTRAYNV-UHFFFAOYSA-K 0.000 description 2
- 229910052749 magnesium Inorganic materials 0.000 description 2
- 239000011777 magnesium Substances 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000003199 nucleic acid amplification method Methods 0.000 description 2
- 238000004537 pulping Methods 0.000 description 2
- 239000002994 raw material Substances 0.000 description 2
- RNFJDJUURJAICM-UHFFFAOYSA-N 2,2,4,4,6,6-hexaphenoxy-1,3,5-triaza-2$l^{5},4$l^{5},6$l^{5}-triphosphacyclohexa-1,3,5-triene Chemical compound N=1P(OC=2C=CC=CC=2)(OC=2C=CC=CC=2)=NP(OC=2C=CC=CC=2)(OC=2C=CC=CC=2)=NP=1(OC=1C=CC=CC=1)OC1=CC=CC=C1 RNFJDJUURJAICM-UHFFFAOYSA-N 0.000 description 1
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 description 1
- BPQQTUXANYXVAA-UHFFFAOYSA-N Orthosilicate Chemical compound [O-][Si]([O-])([O-])[O-] BPQQTUXANYXVAA-UHFFFAOYSA-N 0.000 description 1
- 240000007594 Oryza sativa Species 0.000 description 1
- 235000007164 Oryza sativa Nutrition 0.000 description 1
- 229910019142 PO4 Inorganic materials 0.000 description 1
- 241000209140 Triticum Species 0.000 description 1
- 235000021307 Triticum Nutrition 0.000 description 1
- 238000002441 X-ray diffraction Methods 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- 239000010405 anode material Substances 0.000 description 1
- 238000010009 beating Methods 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 159000000007 calcium salts Chemical class 0.000 description 1
- 239000000919 ceramic Substances 0.000 description 1
- 239000013043 chemical agent Substances 0.000 description 1
- 239000013064 chemical raw material Substances 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 238000000975 co-precipitation Methods 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 230000003588 decontaminative effect Effects 0.000 description 1
- 238000000151 deposition Methods 0.000 description 1
- 238000001514 detection method Methods 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- 235000013399 edible fruits Nutrition 0.000 description 1
- 238000000921 elemental analysis Methods 0.000 description 1
- IMBKASBLAKCLEM-UHFFFAOYSA-L ferrous ammonium sulfate (anhydrous) Chemical compound [NH4+].[NH4+].[Fe+2].[O-]S([O-])(=O)=O.[O-]S([O-])(=O)=O IMBKASBLAKCLEM-UHFFFAOYSA-L 0.000 description 1
- 239000011737 fluorine Substances 0.000 description 1
- 229910052731 fluorine Inorganic materials 0.000 description 1
- 238000009616 inductively coupled plasma Methods 0.000 description 1
- 229910052744 lithium Inorganic materials 0.000 description 1
- 238000012423 maintenance Methods 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 239000010452 phosphate Substances 0.000 description 1
- NBIIXXVUZAFLBC-UHFFFAOYSA-K phosphate Chemical compound [O-]P([O-])([O-])=O NBIIXXVUZAFLBC-UHFFFAOYSA-K 0.000 description 1
- 235000021317 phosphate Nutrition 0.000 description 1
- 239000007774 positive electrode material Substances 0.000 description 1
- 238000004321 preservation Methods 0.000 description 1
- 230000002265 prevention Effects 0.000 description 1
- 230000033764 rhythmic process Effects 0.000 description 1
- 235000009566 rice Nutrition 0.000 description 1
- 238000013341 scale-up Methods 0.000 description 1
- 235000011121 sodium hydroxide Nutrition 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 230000002194 synthesizing effect Effects 0.000 description 1
- 235000013311 vegetables Nutrition 0.000 description 1
Images
Classifications
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
- C01B25/00—Phosphorus; Compounds thereof
- C01B25/16—Oxyacids of phosphorus; Salts thereof
- C01B25/26—Phosphates
- C01B25/28—Ammonium phosphates
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
- C01B25/00—Phosphorus; Compounds thereof
- C01B25/16—Oxyacids of phosphorus; Salts thereof
- C01B25/26—Phosphates
- C01B25/37—Phosphates of heavy metals
- C01B25/375—Phosphates of heavy metals of iron
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- C01P2002/00—Crystal-structural characteristics
- C01P2002/70—Crystal-structural characteristics defined by measured X-ray, neutron or electron diffraction data
- C01P2002/72—Crystal-structural characteristics defined by measured X-ray, neutron or electron diffraction data by d-values or two theta-values, e.g. as X-ray diagram
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- C01P2006/00—Physical properties of inorganic compounds
- C01P2006/80—Compositional purity
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/10—Energy storage using batteries
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- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Inorganic Chemistry (AREA)
- Removal Of Specific Substances (AREA)
Abstract
The invention discloses a filtering and impurity removing method for ammonium monohydrogen phosphate or ammonium dihydrogen phosphate, belonging to the field of battery materials. According to the method for filtering and removing impurities from the ammonium monohydrogen phosphate or the ammonium dihydrogen phosphate, the ferrous ammonium phosphate generated by the reaction of ferrous sulfate and part of the ammonium monohydrogen phosphate or the ammonium dihydrogen phosphate adsorbs and wraps insoluble impurities in the solution of the ammonium monohydrogen phosphate or the ammonium dihydrogen phosphate, so that the particle size of the impurities is increased, filter cloth pores are not easy to block during filtering, filter residues are extremely easy to remove, the cleaning frequency of the filter cloth is greatly reduced, and the problem that the ammonium monohydrogen phosphate or the ammonium dihydrogen phosphate is difficult to filter is fundamentally solved. The filtering and impurity removing method greatly improves the impurity removing efficiency and the product quality of the ammonium dihydrogen phosphate or the ammonium dihydrogen phosphate, can be used for a large-scale impurity removing process, and has wide application prospect.
Description
Technical Field
The invention relates to the field of battery materials, in particular to a filtering and impurity removing method for ammonium dihydrogen phosphate or ammonium dihydrogen phosphate.
Background
Ammonium monohydrogen phosphate is widely used for printing plate making, medicine, fire prevention, electronic tubes and the like, is a high-efficiency fertilizer widely applied to vegetables, fruits, rice and wheat, and is also industrially used as a feed additive, a flame retardant, a fire extinguishing agent and the like. Ammonium dihydrogen phosphate is an important chemical raw material, also known as monoammonium phosphate (MAP), and is commonly used as a fertilizer, a fire retardant, and also used in pharmaceuticals, feed additives, and the like.
In recent years, with the development of new energy industry, ammonium monohydrogen phosphate or ammonium dihydrogen phosphate is used as one of the main raw materials of the positive electrode material iron phosphate of the battery, and the demand of the ammonium monohydrogen phosphate or the ammonium dihydrogen phosphate is increasing year by year. However, a large amount of impurities are introduced in the preparation process of the iron phosphate and the iron phosphate, so that the quality of the iron phosphate is influenced.
In order to improve the quality of iron phosphate, impurities in the raw material ammonium monohydrogen phosphate or ammonium dihydrogen phosphate must be removed. The ammonium monohydrogen phosphate or ammonium dihydrogen phosphate solution is usually filtered and decontaminated by using a plate-and-frame filter press, but the ammonium monohydrogen phosphate or ammonium dihydrogen phosphate dissolved in the method has a slow filtering speed, and insoluble impurity particles in the solution easily block the filter cloth until the filter cloth can not be filtered, so the production cost is greatly increased. Elemental analysis of insoluble impurities revealed that the main components of the insoluble impurities were phosphate, silicate, calcium salt, and the like. In order to improve the impurity removal efficiency, the CN104548754B and the CN114712941A both adopt a mode of configuring a chemical agent to clean filter cloth to solve the problem that the filter cloth is blocked by ammonium dihydrogen phosphate solution filtration and impurity removal, and although the filtration efficiency is rapidly improved in a short period, the problem that the ammonium dihydrogen phosphate is difficult to filter is not fundamentally solved. Therefore, a simple and efficient filtering and impurity removing method for ammonium monohydrogen phosphate or ammonium dihydrogen phosphate is researched and developed, and the improvement of the quality of the battery cathode material iron phosphate is very important.
Disclosure of Invention
In view of the above, the technical problem to be solved by the present invention is to provide a method for filtering and removing impurities from ammonium monohydrogen phosphate or ammonium dihydrogen phosphate. The filtering and impurity removing method greatly shortens the filtering time and improves the impurity removing efficiency and quality of ammonium monohydrogen phosphate or ammonium dihydrogen phosphate.
In order to achieve the above purpose, the technical scheme adopted by the invention is as follows:
the invention provides a filtering and impurity removing method of ammonium monohydrogen phosphate or ammonium dihydrogen phosphate, which comprises the following steps:
1) Adjusting the pH value of the ammonium dihydrogen phosphate solution or the ammonium dihydrogen phosphate solution to be neutral;
2) Mixing a ferrous sulfate solution with the neutral ammonium monohydrogen phosphate solution or the neutral ammonium dihydrogen phosphate solution, reacting ferrous sulfate with part of the ammonium monohydrogen phosphate or the ammonium dihydrogen phosphate to obtain ammonium ferrous phosphate flocs, and adsorbing insoluble particles in the ammonium monohydrogen phosphate solution or the ammonium dihydrogen phosphate solution by the ammonium ferrous phosphate flocs to obtain a system S1;
3) And (3) carrying out suction filtration on the system S1 to obtain the ammonium monohydrogen phosphate or ammonium dihydrogen phosphate solution after impurity removal.
Preferably, the solvents of the ammonium monohydrogen phosphate or ammonium dihydrogen phosphate solution and the ferrous sulfate solution are respectively selected from one or more of deionized water, steam condensate water and washing mother liquor.
In the preparation of ammonium monohydrogen phosphate or ammonium dihydrogen phosphate solution and ferrous sulfate solution in the specific embodiment of the invention, deionized water is selected as the solvent in order to introduce as little or no impurities as possible.
Preferably, in the step 1), one or more of ammonia water, caustic soda liquid and ammonium bicarbonate solution is used for adjusting the pH value of the solution.
According to the invention, ferrous sulfate is added into the ammonium dihydrogen phosphate or ammonium dihydrogen phosphate solution to react with part of the ammonium dihydrogen phosphate or ammonium dihydrogen phosphate to generate the ammonium ferrous phosphate, the ammonium ferrous phosphate can well adsorb and wrap insoluble particles in the ammonium dihydrogen phosphate or ammonium dihydrogen phosphate solution, so that the particle size of impurity particles in the solution is increased, the filter cloth pores are not easily blocked during filtering, the filtering time is shortened, and the impurity removal efficiency is improved.
Preferably, the mass concentration of the ferrous sulfate solution in the step 2) is 10-20%; more preferably 20%.
Preferably, the mass of the ferrous sulfate in the step 2) is 3.5-7 per mill of ammonium dihydrogen phosphate or ammonium dihydrogen phosphate; more preferably 3.5% o.
Preferably, the temperature of the reaction in the step 2) is 30-45 ℃; more preferably 40 to 45 ℃; further preferably 45 ℃.
Preferably, the stirring speed of the reaction in the step 2) is 50-250 r/min; more preferably 50 to 100r/min; more preferably 100r/min. The generated ferrous ammonium phosphate floc is smashed at an excessively high stirring speed, so that insoluble particles in a system cannot be effectively wrapped, and the filtration efficiency of ammonium monohydrogen phosphate or ammonium dihydrogen phosphate is reduced.
Preferably, the stirring time of the reaction in the step 2) is 20-50 min; more preferably 40 to 50min; more preferably 40min. When the stirring time exceeds 40min, the filtration and impurity removal efficiency of ammonium monohydrogen phosphate or ammonium dihydrogen phosphate is not obviously improved along with the extension of the stirring time, and the optimal stirring time is selected to be 40min in consideration of industrial production cost.
Preferably, the step 3) further comprises washing after the suction filtration.
Preferably, the washing liquid is selected from one or more of deionized water, steam condensate water and washing mother liquor.
Preferably, the washed washing mother liquor is recycled as a solvent of ammonium monohydrogen phosphate solution or ammonium dihydrogen phosphate solution or ferrous sulfate solution.
The filtering and impurity removing method provided by the invention has good applicability to filter cloth, and is applicable to filter cloth of different types and different air permeabilities.
Preferably, the air permeability of the filter cloth subjected to suction filtration in the step 3) is 0-10L/M 2 (ii) S; more preferably 0 to 5L/M 2 and/S. The air permeability is higher (6-10L/M) 2 S) filter cloth, although the filtration rate is faster, the clarity and quality of the filtrate are poor after filtration, and therefore the air permeability is preferably 0 to 5L/M 2 And filtering the filter cloth of/S.
Compared with the prior art, the method for filtering and removing the impurities from the ammonium monohydrogen phosphate or the ammonium dihydrogen phosphate provided by the invention has the advantages that the ferrous ammonium phosphate generated by the reaction of ferrous sulfate and part of the ammonium monohydrogen phosphate or the ammonium dihydrogen phosphate adsorbs and wraps insoluble impurities in the ammonium monohydrogen phosphate or the ammonium dihydrogen phosphate solution, so that the particle size of the impurities is increased, the filter cloth pores are not easily blocked during filtering, and filter residues are easily removed, so that the cleaning frequency of the filter cloth is greatly reduced, and the problem that the ammonium monohydrogen phosphate or the ammonium dihydrogen phosphate is difficult to filter is fundamentally solved. The filtering and impurity removing method greatly improves the impurity removing efficiency and the product quality of the ammonium dihydrogen phosphate or the ammonium dihydrogen phosphate, can be used for a large-scale impurity removing process, and has wide application prospect.
Drawings
Fig. 1 is XRD patterns of iron phosphates synthesized in application example 2, application example 3, and comparative application example 1;
FIG. 2 is a flow chart of an embodiment of the present invention.
Detailed Description
In order to further illustrate the present invention, the method for filtering and removing impurities from ammonium monohydrogen phosphate or ammonium dihydrogen phosphate provided by the present invention is described in detail with reference to the following examples.
Ammonium dihydrogen phosphate (monoammonium phosphate), ammonia water, ferrous sulfate, polyaluminum chloride, polyacrylamide, and polyaluminum ferric chloride, which are described below, are commercially available.
The following examples are directed to the filtration and decontamination of monoammonium phosphate, and the filtration and decontamination method of the present invention is also applicable to monoammonium phosphate.
Example 1
Weighing 700g of monoammonium phosphate, adding 1000g of deionized water, stirring and dissolving to obtain a turbid monoammonium phosphate solution; weighing a certain amount of ammonia water, slowly adding the ammonia water into the dissolved monoammonium phosphate solution, and adjusting the pH value of the solution to be neutral; weighing 5g of ferrous sulfate, adding deionized water to prepare a 10wt% ferrous sulfate solution, and filtering for later use.
Controlling the temperature of the monoammonium phosphate solution to be about 45 ℃ and the stirring speed to be 100r/min; weighing about 24.5g of the prepared 10wt% ferrous sulfate solution, slowly adding the weighed 10wt% ferrous sulfate solution into the monoammonium phosphate solution in three batches, stirring while adding, and controlling the completion of the addition within about 5 min. And after the ferrous sulfate solution is added, stirring at the same speed for 40min to generate light green flocculent ammonium ferrous phosphate, and continuously stirring to continuously adsorb insoluble particles in the monoammonium phosphate solution to obtain a relatively clear mixed solution.
Filter cloth I (air permeability is 0-5L/M) 2 S) filling the mixture in a Buchner funnel to replace filter paper, adding water for wetting, and performing suction filtration for a period of time to enable the mixture to be tightly attached; and (3) slowly transferring the mixed solution into a Buchner funnel for suction filtration, repeatedly washing the filter residue with deionized water, and after 15min, completing suction filtration to obtain the impurity-removed monoammonium phosphate filtrate.
Example 2
Weighing 700g of monoammonium phosphate, adding 1000g of deionized water, stirring and dissolving to obtain a turbid monoammonium phosphate solution; weighing a certain amount of ammonia water, slowly adding the ammonia water into the dissolved monoammonium phosphate solution, and adjusting the pH value of the solution to be neutral; weighing 5g of ferrous sulfate, adding deionized water to prepare a 20wt% ferrous sulfate solution, and filtering for later use.
Controlling the temperature of the monoammonium phosphate solution to be about 45 ℃ and the stirring speed to be 100r/min; weighing about 12.3g of prepared 20wt% ferrous sulfate solution, slowly adding into the monoammonium phosphate solution in three batches while stirring, and controlling the completion of the addition within about 5 min; and after the ferrous sulfate solution is added, stirring at the same speed for 40min to generate light green flocculent ammonium ferrous phosphate, and continuously stirring to continuously adsorb insoluble particles in the monoammonium phosphate solution to obtain a relatively clear mixed solution.
Filtering cloth I (air permeability is 0-5L/M) 2 and/S) is filled in a Buchner funnel to replace filter paper, and is filtered and tightly attached after being wetted by water. And slowly transferring the mixed solution into a Buchner funnel for suction filtration, repeatedly washing the filter residue with deionized water, and performing suction filtration after 12min to obtain the impurity-removed monoammonium phosphate filtrate.
Example 3
Weighing 700g of monoammonium phosphate, adding 1000g of deionized water, stirring and dissolving to obtain a turbid monoammonium phosphate solution; weighing a certain amount of ammonia water, slowly adding the ammonia water into the dissolved monoammonium phosphate solution, and adjusting the pH value of the solution to be neutral; weighing 5g of ferrous sulfate, adding deionized water to prepare a 20wt% ferrous sulfate solution, and filtering for later use.
Controlling the temperature of the monoammonium phosphate solution to be about 30 ℃, and stirring at 100r/min; weighing about 12.3g of prepared 20wt% ferrous sulfate solution, slowly adding into the monoammonium phosphate solution in three batches while stirring, and controlling the completion of the addition within about 5 min; and after the ferrous sulfate solution is added, stirring at the same speed for 40min to generate light green flocculent ammonium ferrous phosphate, and continuously stirring to continuously adsorb insoluble particles in the monoammonium phosphate solution to obtain a relatively clear mixed solution.
Filter cloth I (air permeability is 0-5L/M) 2 and/S) is filled in a Buchner funnel to replace filter paper, and is filtered and tightly attached after being wetted by water. And (3) slowly transferring the mixed solution to a Buchner funnel for suction filtration, repeatedly washing the filter residue with deionized water, and after 19min, completing suction filtration to obtain the impurity-removed monoammonium phosphate filtrate.
Example 4
Weighing 700g of monoammonium phosphate, adding 1000g of deionized water, stirring and dissolving to obtain a turbid monoammonium phosphate solution; weighing a certain amount of ammonia water, slowly adding the ammonia water into the dissolved monoammonium phosphate solution, and adjusting the pH value of the solution to be neutral; weighing 5g of ferrous sulfate, adding deionized water to prepare a 20wt% ferrous sulfate solution, and filtering for later use.
Controlling the temperature of the monoammonium phosphate solution to be about 45 ℃ and the stirring speed to be 50r/min; weighing about 12.3g of prepared 20wt% ferrous sulfate solution, slowly adding into the monoammonium phosphate solution in three batches while stirring, and controlling the completion of the addition within about 5 min; and after the ferrous sulfate solution is added, stirring at the same speed for 40min to generate light green flocculent ammonium ferrous phosphate, and continuously stirring to continuously adsorb insoluble particles in the monoammonium phosphate solution to obtain a relatively clear mixed solution.
Filter cloth I (air permeability is 0-5L/M) 2 and/S) is filled in a Buchner funnel to replace filter paper, and is filtered and tightly attached after being wetted by water. And slowly transferring the mixed solution into a Buchner funnel for suction filtration, repeatedly washing the filter residue with deionized water, and performing suction filtration after 25min to obtain impurity-removed monoammonium phosphate filtrate.
Example 5
Weighing 700g of monoammonium phosphate, adding 1000g of deionized water, stirring and dissolving to obtain a turbid monoammonium phosphate solution; weighing a certain amount of ammonia water, slowly adding the ammonia water into the dissolved monoammonium phosphate solution, and adjusting the pH value of the solution to be neutral; weighing 5g of ferrous sulfate, adding deionized water to prepare a 20wt% ferrous sulfate solution, and filtering for later use.
Controlling the temperature of the monoammonium phosphate solution to be about 45 ℃, and stirring at the speed of 250r/min; weighing about 12.3g of prepared 20wt% ferrous sulfate solution, slowly adding into the monoammonium phosphate solution in three batches, stirring while adding, and controlling the completion of the addition within about 5 min; and after the ferrous sulfate solution is added, stirring at the same speed for 40min to generate light green flocculent ammonium ferrous phosphate, and continuously stirring to continuously adsorb insoluble particles in the monoammonium phosphate solution to obtain a relatively clear mixed solution.
Filter cloth I (air permeability is 0-5L/M) 2 and/S) placing the filter paper in a Buchner funnel instead of filter paper, adding water for wetting, and performing suction filtration for a period of time to make the filter paper close. And (3) slowly transferring the mixed solution into a Buchner funnel for suction filtration, repeatedly washing the filter residue with deionized water, and after 35min, completing suction filtration to obtain the impurity-removed monoammonium phosphate filtrate.
Example 6
Weighing 700g of monoammonium phosphate, adding 1000g of deionized water, stirring and dissolving to obtain a turbid monoammonium phosphate solution; weighing a certain amount of ammonia water, slowly adding the ammonia water into the dissolved monoammonium phosphate solution, and adjusting the pH value of the solution to be neutral; weighing 5g of ferrous sulfate, adding deionized water to prepare a 20wt% ferrous sulfate solution, and filtering for later use.
Controlling the temperature of the monoammonium phosphate solution to be about 45 ℃, and stirring at 100r/min; weighing about 12.3g of prepared 20wt% ferrous sulfate solution, slowly adding into the monoammonium phosphate solution in three batches, stirring while adding, and controlling the completion of the addition within about 5 min; and after the ferrous sulfate solution is added, stirring at the same speed for 20min to generate light green flocculent ammonium ferrous phosphate, and continuously stirring to continuously adsorb insoluble particles in the monoammonium phosphate solution to obtain a relatively clear mixed solution.
Filter cloth I (air permeability is 0-5L/M) 2 and/S) is filled in a Buchner funnel to replace filter paper, and is filtered and tightly attached after being wetted by water. Mixing the above materialsAnd slowly transferring the solution into a Buchner funnel for suction filtration, repeatedly washing the filter residue with deionized water, and performing suction filtration after 28min to obtain the impurity-removed monoammonium phosphate filtrate.
Example 7
Weighing 700g of monoammonium phosphate, adding 1000g of deionized water, stirring and dissolving to obtain a turbid monoammonium phosphate solution; weighing a certain amount of ammonia water, slowly adding the ammonia water into the dissolved monoammonium phosphate solution, and adjusting the pH value of the solution to be neutral; weighing 5g of ferrous sulfate, adding deionized water to prepare a 20wt% ferrous sulfate solution, and filtering for later use.
Controlling the temperature of the monoammonium phosphate solution to be about 45 ℃ and the stirring speed to be 100r/min; weighing about 12.3g of prepared 20wt% ferrous sulfate solution, slowly adding into the monoammonium phosphate solution in three batches, stirring while adding, and controlling the completion of the addition within about 5 min; and after the ferrous sulfate solution is added, stirring at the same speed for 50min to generate light green flocculent ammonium ferrous phosphate, and continuously stirring to continuously adsorb insoluble particles in the monoammonium phosphate solution to obtain a relatively clear mixed solution.
Filter cloth I (air permeability is 0-5L/M) 2 and/S) is filled in a Buchner funnel to replace filter paper, and is filtered and tightly attached after being wetted by water. And (3) slowly transferring the mixed solution into a Buchner funnel for suction filtration, repeatedly washing the filter residue with deionized water, and after 12min, completing suction filtration to obtain the impurity-removed monoammonium phosphate filtrate.
Example 8
Weighing 700g of monoammonium phosphate, adding 1000g of deionized water, stirring and dissolving to obtain a turbid monoammonium phosphate solution; weighing a certain amount of ammonia water, slowly adding the ammonia water into the dissolved monoammonium phosphate solution, and adjusting the pH value of the solution to be neutral; weighing 5g of ferrous sulfate, adding deionized water to prepare a 20wt% ferrous sulfate solution, and filtering for later use.
Controlling the temperature of the monoammonium phosphate solution to be about 45 ℃ and the stirring speed to be 100r/min; weighing about 24.5g of prepared 20wt% ferrous sulfate solution, slowly adding into the monoammonium phosphate solution in three batches while stirring, and controlling the completion of the addition within about 5 min; and after the ferrous sulfate solution is added, stirring at the same speed for 40min to generate light green flocculent ammonium ferrous phosphate, and continuously stirring to continuously adsorb insoluble particles in the monoammonium phosphate solution to obtain a relatively clear mixed solution.
Filter cloth I (air permeability is 0-5L/M) 2 and/S) placing the filter paper in a Buchner funnel instead of filter paper, adding water for wetting, and performing suction filtration for a period of time to make the filter paper close. And slowly transferring the mixed solution into a Buchner funnel for suction filtration, repeatedly washing the filter residue with deionized water, and performing suction filtration after 13min to obtain impurity-removed monoammonium phosphate filtrate.
Example 9
Weighing 700g of monoammonium phosphate, adding 1000g of deionized water, stirring and dissolving to obtain a turbid monoammonium phosphate solution; weighing a certain amount of ammonia water, slowly adding the ammonia water into the dissolved monoammonium phosphate solution, and adjusting the pH value of the solution to be neutral; weighing 5g of ferrous sulfate, adding deionized water to prepare a 20wt% ferrous sulfate solution, and filtering for later use.
Controlling the temperature of the monoammonium phosphate solution to be about 45 ℃ and the stirring speed to be 100r/min; weighing about 12.3g of prepared 20wt% ferrous sulfate solution, slowly adding into the monoammonium phosphate solution in three batches while stirring, and controlling the completion of the addition within about 5 min; and after the ferrous sulfate solution is added, stirring at the same speed for 40min to generate light green flocculent ammonium ferrous phosphate, and continuously stirring to continuously adsorb insoluble particles in the monoammonium phosphate solution to obtain a relatively clear mixed solution.
Filter cloth II (air permeability is 6-10L/M) 2 and/S) placing the filter paper in a Buchner funnel instead of filter paper, adding water for wetting, and performing suction filtration for a period of time to make the filter paper close. And slowly transferring the mixed solution into a Buchner funnel for suction filtration, repeatedly washing the filter residue with deionized water, and performing suction filtration after 8min to obtain impurity-removed monoammonium phosphate filtrate.
Comparative example 1
Weighing 700g of monoammonium phosphate, adding 1000g of deionized water, stirring and dissolving to obtain a turbid monoammonium phosphate solution; and weighing a certain amount of ammonia water, slowly adding the ammonia water into the dissolved monoammonium phosphate solution, and adjusting the pH value of the solution to be neutral.
Controlling the temperature of the monoammonium phosphate solution to be about 45 ℃, stirring at the speed of 100r/min, and stirring for 40min;
filter cloth (air permeability 0-5L/M) 2 S) filling the mixture in a Buchner funnel to replace filter paper, adding water for wetting, and performing suction filtration for a period of time to enable the mixture to be tightly attached; the neutralized monoammonium phosphate solution was slowly transferred to a buchner funnel and filtered with suction. Repeatedly washing the filter residue with deionized water, and suction-filtering for about 35min, and gradually filtering the solution until no liquid drops, to obtain part of impurity-removed monoammonium phosphate filtrate.
Comparative example 2
Weighing 700g of monoammonium phosphate, adding 1000g of deionized water, stirring and dissolving to obtain a turbid monoammonium phosphate solution; weighing a certain amount of ammonia water, slowly adding the ammonia water into the dissolved monoammonium phosphate solution, and adjusting the pH value of the solution to be neutral; then 5g of polyaluminum chloride (PAC) is weighed, deionized water is added to prepare a 15wt% polyaluminum chloride (PAC) solution, and the solution is filtered for standby.
Controlling the temperature of the solution to be about 45 ℃ and the stirring speed to be 100r/min; weighing about 16.3g of prepared 15wt% polyaluminium chloride (PAC) solution, slowly adding into the monoammonium phosphate solution in three batches, stirring while adding, and controlling the completion of the addition within about 5 min. After the polyaluminum chloride (PAC) solution is added, stirring at the same speed for 40min to obtain a turbid solution, wherein only a small amount of floccule precipitates at the bottom, and continuously stirring to adsorb insoluble particles in the monoammonium phosphate solution to obtain a clear mixed solution.
Filter cloth (air permeability 0-5L/M) 2 S) placing the filter paper in a Buchner funnel instead of filter paper, adding water for wetting, and performing suction filtration for a period of time to enable the filter paper to be attached tightly; and (3) slowly transferring the mixed solution into a Buchner funnel for suction filtration, repeatedly washing filter residues with deionized water, and after 33min of suction filtration, gradually filtering the solution until no liquid drops drop completely due to filter cloth blockage, so that only a part of impurity-removed monoammonium phosphate filtrate is obtained.
Comparative example 3
Weighing 700g of monoammonium phosphate, adding 1000g of deionized water, stirring and dissolving to obtain a turbid monoammonium phosphate solution; weighing a certain amount of ammonia water, slowly adding the ammonia water into the dissolved monoammonium phosphate solution, and adjusting the pH value of the solution to be neutral; then 5g of polyacrylamide is weighed and added into deionized water to prepare 15wt% of polyacrylamide solution, and the solution is filtered for standby.
Controlling the temperature of the monoammonium phosphate solution to be about 45 ℃ and the stirring speed to be 100r/min; weighing about 16.3g of the prepared 15wt% polyacrylamide solution, slowly adding the solution into the monoammonium phosphate solution in three batches while stirring, and controlling the completion of the addition within about 5 min. After the polyacrylamide solution is added, stirring at the same speed for 40min to obtain a turbid solution, wherein only a small amount of floccule precipitates at the bottom, and continuously stirring to adsorb insoluble particles in the monoammonium phosphate solution to obtain a clear mixed solution.
Filter cloth I (air permeability is 0-5L/M) 2 S) filling the mixture in a Buchner funnel to replace filter paper, adding water for wetting, and performing suction filtration for a period of time to enable the mixture to be tightly attached; and slowly transferring the mixed solution into a Buchner funnel for suction filtration, repeatedly washing filter residues with deionized water, and after 38min of suction filtration, gradually filtering the solution slowly until no liquid drops drop completely due to filter cloth blockage, so that only part of impurity-removed monoammonium phosphate filtrate is obtained.
Comparative example 4
Weighing 700g of monoammonium phosphate, adding 1000g of deionized water, stirring and dissolving to obtain a turbid monoammonium phosphate solution; weighing a certain amount of ammonia water, slowly adding the ammonia water into the dissolved monoammonium phosphate solution, and adjusting the pH value of the solution to be neutral; then 5g of polyaluminum ferric chloride is weighed, deionized water is added to prepare a 15wt% polyaluminum ferric chloride solution, and the solution is filtered for later use.
Controlling the temperature of the monoammonium phosphate solution to be about 45 ℃, and stirring at 100r/min; weighing about 16.3g of the prepared 15wt% polyaluminum ferric chloride solution, slowly adding the solution into the monoammonium phosphate solution in three batches while stirring, and controlling the completion of the addition within about 5 min. After the polymeric aluminum ferric chloride solution is added, stirring at the same speed for 40min to obtain a turbid solution, only a small amount of floccule precipitates at the bottom, and continuously stirring to adsorb insoluble particles in the monoammonium phosphate solution to obtain a clear mixed solution.
Filter cloth I (air permeability 0 ℃)5L/M 2 S) filling the mixture in a Buchner funnel to replace filter paper, adding water for wetting, and performing suction filtration for a period of time to enable the mixture to be tightly attached; and slowly transferring the mixed solution into a Buchner funnel for suction filtration, repeatedly washing filter residues with deionized water, and after 28min of suction filtration, gradually filtering the solution slowly until no liquid drops drop completely due to filter cloth blockage, so that only part of impurity-removed monoammonium phosphate filtrate is obtained.
Application example 1
Amplification experiment for filtering and impurity removal of monoammonium phosphate solution
Weighing 70kg of monoammonium phosphate, adding 100kg of deionized water, stirring and dissolving to obtain a turbid monoammonium phosphate solution; weighing a certain amount of ammonia water, slowly adding the ammonia water into the dissolved monoammonium phosphate solution, and adjusting the pH value of the solution to be neutral; weighing 500g of ferrous sulfate, adding deionized water to prepare a 20wt% ferrous sulfate solution, and filtering for later use.
Controlling the temperature of the monoammonium phosphate solution to be about 45 ℃, and stirring at 100r/min; weighing about 1.23kg of the prepared 20wt% ferrous sulfate solution, slowly adding into the monoammonium phosphate solution in three batches, stirring while adding, and controlling the completion of the addition within about 10 min; and after the ferrous sulfate solution is added, stirring at the same speed for 40min to generate light green flocculent ammonium ferrous phosphate, and continuously stirring to continuously adsorb insoluble particles in the monoammonium phosphate solution to obtain a relatively clear mixed solution.
Filter cloth I (air permeability is 0-5L/M) 2 and/S) placing the filter paper in a Buchner funnel instead of filter paper, adding water for wetting, and performing suction filtration for a period of time to make the filter paper close. And slowly transferring the mixed solution into a Buchner funnel for suction filtration, repeatedly washing the filter residue with deionized water, and carrying out suction filtration for 25min to obtain the impurity-removed monoammonium phosphate filtrate. The above examples 1 to 9 and comparative examples 1 to 4 were compared, and the scale-up experiment was performed by applying example 1 to the filtration and impurity removal of example 2, and the experimental results are shown in table 1.
TABLE 1 comparison of the filtration results of the examples
Note: -means no charge.
Through comparison of the experimental results of examples 1 to 9 and comparative examples 1 to 4 in table 1, it is found that different kinds of flocculants have different effects on the filtration of the monoammonium phosphate solution, wherein the addition of the ferrous sulfate solution can significantly improve the filtration efficiency of the monoammonium phosphate solution and shorten the filtration time. In addition, the filtration efficiency of the monoammonium phosphate solution is affected by changes of the concentration and the addition amount of the flocculating agent ferrous sulfate, the reaction temperature, the stirring speed and the stirring time, the air permeability of the filter cloth and the like. The stirring speed, the stirring time and the reaction temperature are key factors influencing the filtration efficiency of the monoammonium phosphate, and the rotating speed is found to be too fast in the test process, so that generated ammonium ferrous phosphate flocs can be smashed, and impurities in the monoammonium phosphate solution can not be effectively wrapped. In addition, the short stirring time or the low reaction temperature can influence the impurities wrapped by the flocs and reduce the filtering efficiency. When the temperature is as low as 30 ℃, the growth rate of flocs is obviously slowed down, so that the impurity removal efficiency is reduced, and through continuous tests, after the pH value of the monoammonium phosphate solution is adjusted, the filtration effect of the monoammonium phosphate solution is better when the solution temperature is controlled to be about 45 ℃, so that the 45 ℃ is a better stirring temperature; when the stirring time exceeds 40min, the filtration efficiency is not greatly improved, and the optimal stirring time is set to be 40min in consideration of the rhythm and cost of industrial production. The results of kilogram-level pilot test (application example 1) show that the filtration and impurity removal method for monoammonium phosphate can be used for amplification experiments, and has stable impurity removal effect and good application prospect.
The results shown in table 2 were obtained by analyzing the impurity elements of the monoammonium phosphate filtrate obtained in the above examples, and table 2 shows the results of analyzing the impurity elements of the monoammonium phosphate filtrate obtained in examples 1 to 9, comparative examples 1 to 4, and the solid residue obtained in application example 1.
TABLE 2 analysis results of impurity elements of monoammonium phosphate filtrate
As can be seen from the data in table 2: the ferrous sulfate is added into the embodiments 1 to 9 to serve as the flocculating agent, so that the purity of the monoammonium phosphate solution is obviously improved compared with the comparative examples 1 to 4, wherein the elements such as calcium, magnesium and the like are obviously reduced, and most of fluoride ions are reduced to be below 100ppm, so that the corrosion of the monoammonium phosphate solution to metal, ceramic and other equipment can be relieved, and the maintenance cost of the equipment in the iron phosphate production process is reduced. In addition, element analysis is carried out on the filter residue obtained after the suction filtration in the example 1, and the result shows that the contents of calcium and magnesium in the filter residue are extremely high, and the content of fluorine ions exceeds 10000ppm, so that the wrapping and depositing effects of the ferrous ammonium sulfate floc on impurity elements are further verified. Furthermore, by comparing the filtration rates of different types of filter cloth (example 2 and example 9) it can be found that: higher air permeability (6-10L/M) 2 S) filter cloth has higher filtering speed, but the clarity and quality of the filtrate are lower than the air permeability (0-5L/M) 2 The filtrate filtered through the filter cloth of/S), therefore, the air permeability is preferably 0 to 5L/M 2 The filter cloth of the/S is the better filter cloth for filtering monoammonium phosphate.
Application example 2
Preparation of iron phosphate
Taking 500g of the monoammonium phosphate solution obtained in the embodiment 2, adding a phosphoric acid solution to adjust the pH value to 2-3, mixing the monoammonium phosphate solution with 720g of 25wt% ferrous sulfate solution and 85g of hydrogen peroxide (the concentration is 28 wt%), controlling the temperature to be 40-60 ℃ to react to synthesize ferric phosphate, performing suction filtration, mixing the obtained filter cake with 500g of water, adding 8.2g of phosphoric acid, heating to 95 ℃, performing pulping and aging, performing suction filtration after keeping the temperature for 30min, rinsing with deionized water until the conductivity is less than 500us/cm, and drying to obtain ferric phosphate dihydrate. 174g of anhydrous iron phosphate is obtained after calcination, the yield is 97%, and the XRD miscellaneous peak is 2.13% (compared with standard card PDF #77-0094, the main peak characteristic diffraction peaks are kept consistent, the main peak intensity is high, only a trace weak miscellaneous peak exists between the two main peaks, and the XRD miscellaneous peak percentage represents the ratio of the miscellaneous peak intensity to the strongest main peak intensity).
Application example 3
Preparation of iron phosphate
Weighing 500g of the monoammonium phosphate obtained in the example 9, adding a phosphoric acid solution to adjust the pH value to 2-3, mixing the monoammonium phosphate with 720g of 25wt% ferrous sulfate solution and 85g of hydrogen peroxide (the concentration is 28 wt%), reacting to synthesize the ferric phosphate, performing suction filtration, mixing the obtained filter cake with 500g of water, controlling the temperature to be 40-60 ℃, adding 16.2g of phosphoric acid, heating to 95 ℃, performing pulping and aging, preserving the temperature for 30min, performing suction filtration, and washing with deionized water to obtain the ferric phosphate dihydrate. 170g of anhydrous iron phosphate is obtained after calcination, the yield is 95%, and the XRD miscellaneous peak is 8.25% (compared with standard card PDF #77-0094, the main peak characteristic diffraction peaks are all kept consistent, the main peak intensity is high, only a weak miscellaneous peak exists between the two main peaks, and the XRD miscellaneous peak percentage represents the ratio of the miscellaneous peak intensity to the strongest main peak intensity).
Comparative application example 1
Preparation of iron phosphate
Adding 500g of unfiltered monoammonium phosphate solution into phosphoric acid solution to adjust the pH value to 2-3, mixing the phosphoric acid solution with 720g of 25wt% ferrous sulfate solution and 85g of hydrogen peroxide (the concentration is 28 wt%), controlling the temperature to be 40-60 ℃ to react to synthesize ferric phosphate, performing suction filtration, mixing the obtained filter cake with 500g of water, adding 8.2g of phosphoric acid, heating to 95 ℃, performing beating aging, performing suction filtration after heat preservation for 30min, and washing with deionized water to obtain ferric phosphate dihydrate. The anhydrous iron phosphate 168g is obtained after calcination, the yield is 94%, and the XRD miscellaneous peak is 15.28% (compared with the standard card PDF #77-0094, the main peak characteristic diffraction peaks are kept consistent, a relatively obvious weak miscellaneous peak is arranged between the two main peaks, and the XRD miscellaneous peak percentage represents the ratio of the miscellaneous peak intensity to the strongest main peak intensity). In summary, the ferric phosphate is synthesized by reacting monoammonium phosphate with ferrous sulfate solution, hydrogen peroxide and the like by an oxidation homogeneous coprecipitation method. By comparing application examples 2 and 3 with application example 1, the monoammonium phosphate obtained by filtering and removing impurities by the method is found to be shorter in washing procedure and less in water consumption in the process of synthesizing the iron phosphate, so that the production cost of the battery anode material iron phosphate is indirectly reduced. The comparison results are shown in tables 3 and 4, where table 3 is the experimental comparison of application examples 2 and 3 and comparative application example 1, and table 4 is the comparison of the detection results of the corresponding product iron phosphate.
Table 3 experimental comparison for the preparation of iron phosphate
TABLE 4 comparison of the test results for iron phosphate
The data in table 4 show that the iron phosphate obtained in application example 2 and application example 3 has smaller impurity peak, smaller granularity (D50), larger specific surface area, lower content of impurity elements and higher quality of iron phosphate in XRD compared with the iron phosphate finished product obtained in comparative application example 1. Inductively coupled plasma spectrometer
Compared with the iron phosphate finished product synthesized by unfiltered monoammonium phosphate, the monoammonium phosphate obtained by filtering and removing impurities by the method has better quality. The quality of the iron phosphate directly determines the quality of the lithium iron phosphate battery, so the method for filtering and removing impurities from the monoammonium phosphate is greatly beneficial to the development of the lithium iron phosphate cathode material and even the lithium battery industry.
In summary, the filtering and impurity removing method provided by the invention has the advantages that ferrous sulfate is added into the ammonium monohydrogen phosphate or ammonium dihydrogen phosphate solution to react with part of the ammonium monohydrogen phosphate or ammonium dihydrogen phosphate to generate ammonium ferrous phosphate, the ammonium ferrous phosphate can well adsorb and wrap insoluble particles in the ammonium monohydrogen phosphate solution or ammonium dihydrogen phosphate solution, so that the particle size of impurity particles in the solution is increased, filter cloth pores are not easily blocked during filtering, the filtering time is shortened, the impurity removing efficiency is improved, the problem that the ammonium monohydrogen phosphate or ammonium dihydrogen phosphate solution is difficult to filter is fundamentally solved, the impurity removing efficiency and the product quality are greatly improved, the method can be used for a large-scale impurity removing process, and the application prospect is very wide.
The above description of the embodiments is only intended to facilitate the understanding of the method of the invention and its core idea. It should be noted that, for those skilled in the art, without departing from the principle of the present invention, it is possible to make various improvements and modifications to the present invention, and those improvements and modifications also fall within the scope of the claims of the present invention.
Claims (10)
1. A filtering and impurity removing method of ammonium dihydrogen phosphate or ammonium dihydrogen phosphate is characterized by comprising the following steps:
1) Adjusting the pH value of the ammonium dihydrogen phosphate solution or the ammonium dihydrogen phosphate solution to be neutral;
2) Mixing a ferrous sulfate solution with the neutral ammonium dihydrogen phosphate solution or the neutral ammonium dihydrogen phosphate solution, reacting ferrous sulfate with part of the ammonium dihydrogen phosphate or the ammonium dihydrogen phosphate to obtain ammonium ferrous phosphate flocs, and adsorbing insoluble particles in the ammonium dihydrogen phosphate solution or the ammonium dihydrogen phosphate solution to obtain a system S1;
3) And (3) carrying out suction filtration on the system S1 to obtain the ammonium dihydrogen phosphate or ammonium dihydrogen phosphate solution after impurity removal.
2. The method for filtering and impurity removing ammonium monohydrogen phosphate or ammonium dihydrogen phosphate according to claim 1, wherein the solvents of the solution of ammonium monohydrogen phosphate or ammonium dihydrogen phosphate and the solution of ferrous sulfate are respectively selected from one or more of deionized water, steam condensate water and recovered mother liquor.
3. The method for filtering and removing impurities from ammonium monohydrogen phosphate or ammonium dihydrogen phosphate according to claim 1, wherein in the step 1), one or more of ammonia water, liquid alkali and ammonium bicarbonate solution is used for adjusting the pH value of the solution.
4. The method for filtering and purifying ammonium monohydrogen phosphate or ammonium dihydrogen phosphate according to claim 1, wherein the ferrous sulfate solution in the step 2) has a mass concentration of 10-20%.
5. The method for filtering and removing impurities from ammonium monohydrogen phosphate or ammonium dihydrogen phosphate according to claim 1, wherein the mass of the ferrous sulfate in the step 2) is 3.5-7% of that of the ammonium monohydrogen phosphate or the ammonium dihydrogen phosphate.
6. The method for filtering and impurity removing ammonium monohydrogen phosphate or ammonium dihydrogen phosphate according to claim 1, wherein the reaction temperature in the step 2) is 30-45 ℃.
7. The method for filtering and impurity removing ammonium monohydrogen phosphate or ammonium dihydrogen phosphate according to claim 1, wherein the stirring rate of the reaction in the step 2) is 50-250 r/min.
8. The method for filtering and removing impurities from ammonium monohydrogen phosphate or ammonium dihydrogen phosphate according to claim 1, wherein the reaction in the step 2) is stirred for 20-50 min.
9. The method for filtering and removing impurities from ammonium monohydrogen phosphate or ammonium dihydrogen phosphate according to claim 1, wherein the step 3) further comprises washing after suction filtration;
the washing liquid is selected from one or more of deionized water, steam condensate and recovered mother liquor;
and the washed washing mother liquor is recycled as a solvent of ammonium monohydrogen phosphate solution or ammonium dihydrogen phosphate solution or ferrous sulfate solution.
10. The method for filtering and impurity removing of ammonium monohydrogen phosphate or ammonium dihydrogen phosphate according to claim 1, wherein the air permeability of the filter cloth for suction filtration in the step 3) is 0-10L/M 2 /S。
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| CN103086341A (en) * | 2013-02-04 | 2013-05-08 | 瓮福（集团）有限责任公司 | Method for preparing battery-grade iron phosphate by using ferrophosphorus |
| CN103350991A (en) * | 2013-05-08 | 2013-10-16 | 湖北富邦科技股份有限公司 | Ferrous ammonium phosphate sustained-release fertilizer synthesis method |
| CN113307243A (en) * | 2021-07-08 | 2021-08-27 | 河南佰利新能源材料有限公司 | Method for preparing iron phosphate by recycling mother liquor |
| CN115124013A (en) * | 2022-08-05 | 2022-09-30 | 衢州华友钴新材料有限公司 | Preparation method of battery-grade ferric orthophosphate |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103086341A (en) * | 2013-02-04 | 2013-05-08 | 瓮福（集团）有限责任公司 | Method for preparing battery-grade iron phosphate by using ferrophosphorus |
| CN103350991A (en) * | 2013-05-08 | 2013-10-16 | 湖北富邦科技股份有限公司 | Ferrous ammonium phosphate sustained-release fertilizer synthesis method |
| CN113307243A (en) * | 2021-07-08 | 2021-08-27 | 河南佰利新能源材料有限公司 | Method for preparing iron phosphate by recycling mother liquor |
| CN115124013A (en) * | 2022-08-05 | 2022-09-30 | 衢州华友钴新材料有限公司 | Preparation method of battery-grade ferric orthophosphate |
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