CN116621134A - Extraction crystallization process of wet phosphoric acid - Google Patents
Extraction crystallization process of wet phosphoric acid Download PDFInfo
- Publication number
- CN116621134A CN116621134A CN202310580096.2A CN202310580096A CN116621134A CN 116621134 A CN116621134 A CN 116621134A CN 202310580096 A CN202310580096 A CN 202310580096A CN 116621134 A CN116621134 A CN 116621134A
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- China
- Prior art keywords
- phosphoric acid
- extraction
- solvent
- wet
- extractant
- Prior art date
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- NBIIXXVUZAFLBC-UHFFFAOYSA-N Phosphoric acid Chemical compound OP(O)(O)=O NBIIXXVUZAFLBC-UHFFFAOYSA-N 0.000 title claims abstract description 504
- 229910000147 aluminium phosphate Inorganic materials 0.000 title claims abstract description 252
- 238000000605 extraction Methods 0.000 title claims abstract description 165
- 238000000034 method Methods 0.000 title claims abstract description 130
- 238000002425 crystallisation Methods 0.000 title claims abstract description 58
- 230000008025 crystallization Effects 0.000 title claims abstract description 58
- 238000000746 purification Methods 0.000 claims abstract description 71
- 239000000725 suspension Substances 0.000 claims abstract description 57
- 239000002253 acid Substances 0.000 claims abstract description 47
- 238000005406 washing Methods 0.000 claims abstract description 33
- 239000012452 mother liquor Substances 0.000 claims abstract description 22
- 239000012535 impurity Substances 0.000 claims abstract description 16
- 238000006477 desulfuration reaction Methods 0.000 claims abstract description 14
- 230000023556 desulfurization Effects 0.000 claims abstract description 14
- 239000000463 material Substances 0.000 claims abstract description 13
- 239000012071 phase Substances 0.000 claims description 97
- 239000002904 solvent Substances 0.000 claims description 90
- 238000001816 cooling Methods 0.000 claims description 53
- 239000013078 crystal Substances 0.000 claims description 39
- 238000006243 chemical reaction Methods 0.000 claims description 28
- 239000000203 mixture Substances 0.000 claims description 26
- 239000003795 chemical substances by application Substances 0.000 claims description 23
- 239000007788 liquid Substances 0.000 claims description 21
- CMPQUABWPXYYSH-UHFFFAOYSA-N phenyl phosphate Chemical class OP(O)(=O)OC1=CC=CC=C1 CMPQUABWPXYYSH-UHFFFAOYSA-N 0.000 claims description 21
- 150000002576 ketones Chemical class 0.000 claims description 19
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 19
- VTYYLEPIZMXCLO-UHFFFAOYSA-L Calcium carbonate Chemical compound [Ca+2].[O-]C([O-])=O VTYYLEPIZMXCLO-UHFFFAOYSA-L 0.000 claims description 18
- KRKNYBCHXYNGOX-UHFFFAOYSA-N citric acid Chemical class OC(=O)CC(O)(C(O)=O)CC(O)=O KRKNYBCHXYNGOX-UHFFFAOYSA-N 0.000 claims description 16
- 230000003009 desulfurizing effect Effects 0.000 claims description 16
- AYJRCSIUFZENHW-UHFFFAOYSA-L barium carbonate Chemical compound [Ba+2].[O-]C([O-])=O AYJRCSIUFZENHW-UHFFFAOYSA-L 0.000 claims description 14
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 claims description 13
- 238000003756 stirring Methods 0.000 claims description 13
- ZWEHNKRNPOVVGH-UHFFFAOYSA-N 2-Butanone Chemical compound CCC(C)=O ZWEHNKRNPOVVGH-UHFFFAOYSA-N 0.000 claims description 12
- 239000000047 product Substances 0.000 claims description 12
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 10
- KRKNYBCHXYNGOX-UHFFFAOYSA-K Citrate Chemical group [O-]C(=O)CC(O)(CC([O-])=O)C([O-])=O KRKNYBCHXYNGOX-UHFFFAOYSA-K 0.000 claims description 10
- 239000002002 slurry Substances 0.000 claims description 10
- 229910000019 calcium carbonate Inorganic materials 0.000 claims description 9
- LRHPLDYGYMQRHN-UHFFFAOYSA-N N-Butanol Chemical compound CCCCO LRHPLDYGYMQRHN-UHFFFAOYSA-N 0.000 claims description 8
- JHIVVAPYMSGYDF-UHFFFAOYSA-N cyclohexanone Chemical compound O=C1CCCCC1 JHIVVAPYMSGYDF-UHFFFAOYSA-N 0.000 claims description 8
- JBTWLSYIZRCDFO-UHFFFAOYSA-N ethyl methyl carbonate Chemical compound CCOC(=O)OC JBTWLSYIZRCDFO-UHFFFAOYSA-N 0.000 claims description 8
- 238000000926 separation method Methods 0.000 claims description 8
- HLZKNKRTKFSKGZ-UHFFFAOYSA-N tetradecan-1-ol Chemical compound CCCCCCCCCCCCCCO HLZKNKRTKFSKGZ-UHFFFAOYSA-N 0.000 claims description 8
- 239000000706 filtrate Substances 0.000 claims description 7
- QQZOPKMRPOGIEB-UHFFFAOYSA-N 2-Oxohexane Chemical compound CCCCC(C)=O QQZOPKMRPOGIEB-UHFFFAOYSA-N 0.000 claims description 6
- ZFOZVQLOBQUTQQ-UHFFFAOYSA-N Tributyl citrate Chemical compound CCCCOC(=O)CC(O)(C(=O)OCCCC)CC(=O)OCCCC ZFOZVQLOBQUTQQ-UHFFFAOYSA-N 0.000 claims description 6
- KBPLFHHGFOOTCA-UHFFFAOYSA-N caprylic alcohol Natural products CCCCCCCCO KBPLFHHGFOOTCA-UHFFFAOYSA-N 0.000 claims description 6
- 238000001704 evaporation Methods 0.000 claims description 6
- ZSIAUFGUXNUGDI-UHFFFAOYSA-N hexan-1-ol Chemical compound CCCCCCO ZSIAUFGUXNUGDI-UHFFFAOYSA-N 0.000 claims description 6
- PHTQWCKDNZKARW-UHFFFAOYSA-N isoamylol Chemical compound CC(C)CCO PHTQWCKDNZKARW-UHFFFAOYSA-N 0.000 claims description 6
- ZXEKIIBDNHEJCQ-UHFFFAOYSA-N isobutanol Chemical compound CC(C)CO ZXEKIIBDNHEJCQ-UHFFFAOYSA-N 0.000 claims description 6
- FDPIMTJIUBPUKL-UHFFFAOYSA-N pentan-3-one Chemical compound CCC(=O)CC FDPIMTJIUBPUKL-UHFFFAOYSA-N 0.000 claims description 6
- 230000008020 evaporation Effects 0.000 claims description 5
- 238000010438 heat treatment Methods 0.000 claims description 5
- 239000002245 particle Substances 0.000 claims description 5
- DKGAVHZHDRPRBM-UHFFFAOYSA-N Tert-Butanol Chemical compound CC(C)(C)O DKGAVHZHDRPRBM-UHFFFAOYSA-N 0.000 claims description 4
- 239000005456 alcohol based solvent Substances 0.000 claims description 4
- 238000002844 melting Methods 0.000 claims description 4
- 230000008018 melting Effects 0.000 claims description 4
- BSXJTDJJVULBTQ-UHFFFAOYSA-N 2,2,3,3,4,4,5,5,6,6,7,7,8,8,9,9,9-heptadecafluorononan-1-ol Chemical compound OCC(F)(F)C(F)(F)C(F)(F)C(F)(F)C(F)(F)C(F)(F)C(F)(F)C(F)(F)F BSXJTDJJVULBTQ-UHFFFAOYSA-N 0.000 claims description 3
- QZCLKYGREBVARF-UHFFFAOYSA-N Acetyl tributyl citrate Chemical compound CCCCOC(=O)CC(C(=O)OCCCC)(OC(C)=O)CC(=O)OCCCC QZCLKYGREBVARF-UHFFFAOYSA-N 0.000 claims description 3
- 239000004804 Butyryltrihexylcitrate Substances 0.000 claims description 3
- ZAMOUSCENKQFHK-UHFFFAOYSA-N Chlorine atom Chemical compound [Cl] ZAMOUSCENKQFHK-UHFFFAOYSA-N 0.000 claims description 3
- 239000002310 Isopropyl citrate Substances 0.000 claims description 3
- NTIZESTWPVYFNL-UHFFFAOYSA-N Methyl isobutyl ketone Chemical compound CC(C)CC(C)=O NTIZESTWPVYFNL-UHFFFAOYSA-N 0.000 claims description 3
- UIHCLUNTQKBZGK-UHFFFAOYSA-N Methyl isobutyl ketone Natural products CCC(C)C(C)=O UIHCLUNTQKBZGK-UHFFFAOYSA-N 0.000 claims description 3
- 229910019142 PO4 Inorganic materials 0.000 claims description 3
- YSMRWXYRXBRSND-UHFFFAOYSA-N TOTP Chemical compound CC1=CC=CC=C1OP(=O)(OC=1C(=CC=CC=1)C)OC1=CC=CC=C1C YSMRWXYRXBRSND-UHFFFAOYSA-N 0.000 claims description 3
- PYIXRBAUGAEEEW-UHFFFAOYSA-N [3,5-di(propan-2-yl)phenyl] diphenyl phosphate Chemical compound CC(C)C1=CC(C(C)C)=CC(OP(=O)(OC=2C=CC=CC=2)OC=2C=CC=CC=2)=C1 PYIXRBAUGAEEEW-UHFFFAOYSA-N 0.000 claims description 3
- UCVMQZHZWWEPRC-UHFFFAOYSA-L barium(2+);hydrogen carbonate Chemical compound [Ba+2].OC([O-])=O.OC([O-])=O UCVMQZHZWWEPRC-UHFFFAOYSA-L 0.000 claims description 3
- AYJRCSIUFZENHW-DEQYMQKBSA-L barium(2+);oxomethanediolate Chemical compound [Ba+2].[O-][14C]([O-])=O AYJRCSIUFZENHW-DEQYMQKBSA-L 0.000 claims description 3
- APOXBWCRUPJDAC-UHFFFAOYSA-N bis(2,6-dimethylphenyl) hydrogen phosphate Chemical compound CC1=CC=CC(C)=C1OP(O)(=O)OC1=C(C)C=CC=C1C APOXBWCRUPJDAC-UHFFFAOYSA-N 0.000 claims description 3
- NKWPZUCBCARRDP-UHFFFAOYSA-L calcium bicarbonate Chemical compound [Ca+2].OC([O-])=O.OC([O-])=O NKWPZUCBCARRDP-UHFFFAOYSA-L 0.000 claims description 3
- 229910000020 calcium bicarbonate Inorganic materials 0.000 claims description 3
- 239000000460 chlorine Substances 0.000 claims description 3
- 229910052801 chlorine Inorganic materials 0.000 claims description 3
- 150000001860 citric acid derivatives Chemical class 0.000 claims description 3
- 229910052731 fluorine Inorganic materials 0.000 claims description 3
- 239000011737 fluorine Substances 0.000 claims description 3
- SKHXHUZZFVMERR-UHFFFAOYSA-L isopropyl citrate Chemical compound CC(C)OC(=O)CC(O)(C([O-])=O)CC([O-])=O SKHXHUZZFVMERR-UHFFFAOYSA-L 0.000 claims description 3
- 235000019300 isopropyl citrate Nutrition 0.000 claims description 3
- 239000005453 ketone based solvent Substances 0.000 claims description 3
- DWKVLOMZGDTICX-UHFFFAOYSA-N nitrobenzene phosphoric acid Chemical compound OP(O)(O)=O.[O-][N+](=O)C1=CC=CC=C1.[O-][N+](=O)C1=CC=CC=C1 DWKVLOMZGDTICX-UHFFFAOYSA-N 0.000 claims description 3
- YAFOVCNAQTZDQB-UHFFFAOYSA-N octyl diphenyl phosphate Chemical compound C=1C=CC=CC=1OP(=O)(OCCCCCCCC)OC1=CC=CC=C1 YAFOVCNAQTZDQB-UHFFFAOYSA-N 0.000 claims description 3
- RMNODSGCFHVNDC-UHFFFAOYSA-N phenyl bis(2-propan-2-ylphenyl) phosphate Chemical compound CC(C)C1=CC=CC=C1OP(=O)(OC=1C(=CC=CC=1)C(C)C)OC1=CC=CC=C1 RMNODSGCFHVNDC-UHFFFAOYSA-N 0.000 claims description 3
- 239000010452 phosphate Substances 0.000 claims description 3
- NBIIXXVUZAFLBC-UHFFFAOYSA-K phosphate Chemical compound [O-]P([O-])([O-])=O NBIIXXVUZAFLBC-UHFFFAOYSA-K 0.000 claims description 3
- TUUQISRYLMFKOG-UHFFFAOYSA-N trihexyl 2-acetyloxypropane-1,2,3-tricarboxylate Chemical compound CCCCCCOC(=O)CC(C(=O)OCCCCCC)(OC(C)=O)CC(=O)OCCCCCC TUUQISRYLMFKOG-UHFFFAOYSA-N 0.000 claims description 3
- XZZNDPSIHUTMOC-UHFFFAOYSA-N triphenyl phosphate Chemical compound C=1C=CC=CC=1OP(OC=1C=CC=CC=1)(=O)OC1=CC=CC=C1 XZZNDPSIHUTMOC-UHFFFAOYSA-N 0.000 claims description 3
- 238000004042 decolorization Methods 0.000 claims description 2
- KPGXUAIFQMJJFB-UHFFFAOYSA-H tungsten hexachloride Chemical compound Cl[W](Cl)(Cl)(Cl)(Cl)Cl KPGXUAIFQMJJFB-UHFFFAOYSA-H 0.000 claims description 2
- YCKRFDGAMUMZLT-UHFFFAOYSA-N Fluorine atom Chemical compound [F] YCKRFDGAMUMZLT-UHFFFAOYSA-N 0.000 claims 1
- REVZBRXEBPWDRA-UHFFFAOYSA-N Stearyl citrate Chemical compound CCCCCCCCCCCCCCCCCCOC(=O)CC(O)(C(O)=O)CC(O)=O REVZBRXEBPWDRA-UHFFFAOYSA-N 0.000 claims 1
- 239000004138 Stearyl citrate Substances 0.000 claims 1
- TVMXDCGIABBOFY-UHFFFAOYSA-N n-Octanol Natural products CCCCCCCC TVMXDCGIABBOFY-UHFFFAOYSA-N 0.000 claims 1
- 235000021317 phosphate Nutrition 0.000 claims 1
- 239000007790 solid phase Substances 0.000 claims 1
- 235000019330 stearyl citrate Nutrition 0.000 claims 1
- 238000005292 vacuum distillation Methods 0.000 claims 1
- 238000010790 dilution Methods 0.000 abstract description 5
- 239000012895 dilution Substances 0.000 abstract description 5
- 150000001450 anions Chemical class 0.000 abstract description 3
- 150000001768 cations Chemical class 0.000 abstract description 3
- 238000005516 engineering process Methods 0.000 abstract description 2
- YWEUIGNSBFLMFL-UHFFFAOYSA-N diphosphonate Chemical compound O=P(=O)OP(=O)=O YWEUIGNSBFLMFL-UHFFFAOYSA-N 0.000 description 23
- DLYUQMMRRRQYAE-UHFFFAOYSA-N phosphorus pentoxide Inorganic materials O1P(O2)(=O)OP3(=O)OP1(=O)OP2(=O)O3 DLYUQMMRRRQYAE-UHFFFAOYSA-N 0.000 description 23
- 238000002156 mixing Methods 0.000 description 20
- 239000000243 solution Substances 0.000 description 13
- 239000006185 dispersion Substances 0.000 description 11
- 238000001914 filtration Methods 0.000 description 10
- 238000004458 analytical method Methods 0.000 description 9
- 239000003337 fertilizer Substances 0.000 description 9
- 239000002367 phosphate rock Substances 0.000 description 7
- OJMIONKXNSYLSR-UHFFFAOYSA-N phosphorous acid Chemical compound OP(O)O OJMIONKXNSYLSR-UHFFFAOYSA-N 0.000 description 7
- 238000001953 recrystallisation Methods 0.000 description 7
- 239000002699 waste material Substances 0.000 description 7
- 238000007865 diluting Methods 0.000 description 6
- -1 iron-magnesium-aluminum Chemical compound 0.000 description 6
- 229910052698 phosphorus Inorganic materials 0.000 description 6
- 238000004537 pulping Methods 0.000 description 6
- 238000009826 distribution Methods 0.000 description 5
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 description 4
- 125000004122 cyclic group Chemical group 0.000 description 4
- 239000007791 liquid phase Substances 0.000 description 4
- 239000011574 phosphorus Substances 0.000 description 4
- 238000000638 solvent extraction Methods 0.000 description 4
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 3
- 238000007599 discharging Methods 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 238000004945 emulsification Methods 0.000 description 3
- 229910021645 metal ion Inorganic materials 0.000 description 3
- 239000011859 microparticle Substances 0.000 description 3
- 238000011084 recovery Methods 0.000 description 3
- VDIFKDMFGPIVCQ-UHFFFAOYSA-N (2-tert-butylphenyl) diphenyl phosphate Chemical compound CC(C)(C)C1=CC=CC=C1OP(=O)(OC=1C=CC=CC=1)OC1=CC=CC=C1 VDIFKDMFGPIVCQ-UHFFFAOYSA-N 0.000 description 2
- PXGOKWXKJXAPGV-UHFFFAOYSA-N Fluorine Chemical compound FF PXGOKWXKJXAPGV-UHFFFAOYSA-N 0.000 description 2
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 2
- 125000000129 anionic group Chemical group 0.000 description 2
- 150000001875 compounds Chemical class 0.000 description 2
- 230000007547 defect Effects 0.000 description 2
- 238000005265 energy consumption Methods 0.000 description 2
- 150000002148 esters Chemical class 0.000 description 2
- 150000002500 ions Chemical class 0.000 description 2
- 229910052742 iron Inorganic materials 0.000 description 2
- 229940035429 isobutyl alcohol Drugs 0.000 description 2
- 239000002994 raw material Substances 0.000 description 2
- 238000010008 shearing Methods 0.000 description 2
- OYPRJOBELJOOCE-UHFFFAOYSA-N Calcium Chemical compound [Ca] OYPRJOBELJOOCE-UHFFFAOYSA-N 0.000 description 1
- DGAQECJNVWCQMB-PUAWFVPOSA-M Ilexoside XXIX Chemical compound C[C@@H]1CC[C@@]2(CC[C@@]3(C(=CC[C@H]4[C@]3(CC[C@@H]5[C@@]4(CC[C@@H](C5(C)C)OS(=O)(=O)[O-])C)C)[C@@H]2[C@]1(C)O)C)C(=O)O[C@H]6[C@@H]([C@H]([C@@H]([C@H](O6)CO)O)O)O.[Na+] DGAQECJNVWCQMB-PUAWFVPOSA-M 0.000 description 1
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 description 1
- QAOWNCQODCNURD-UHFFFAOYSA-L Sulfate Chemical compound [O-]S([O-])(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-L 0.000 description 1
- 150000005215 alkyl ethers Chemical class 0.000 description 1
- 125000005233 alkylalcohol group Chemical group 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
- 229910052785 arsenic Inorganic materials 0.000 description 1
- RQNWIZPPADIBDY-UHFFFAOYSA-N arsenic atom Chemical compound [As] RQNWIZPPADIBDY-UHFFFAOYSA-N 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 239000006227 byproduct Substances 0.000 description 1
- 239000011575 calcium Substances 0.000 description 1
- 229910052791 calcium Inorganic materials 0.000 description 1
- PASHVRUKOFIRIK-UHFFFAOYSA-L calcium sulfate dihydrate Chemical compound O.O.[Ca+2].[O-]S([O-])(=O)=O PASHVRUKOFIRIK-UHFFFAOYSA-L 0.000 description 1
- 238000009388 chemical precipitation Methods 0.000 description 1
- 238000004140 cleaning Methods 0.000 description 1
- 239000012141 concentrate Substances 0.000 description 1
- 230000001419 dependent effect Effects 0.000 description 1
- 239000000839 emulsion Substances 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 238000005342 ion exchange Methods 0.000 description 1
- 238000011031 large-scale manufacturing process Methods 0.000 description 1
- 239000011777 magnesium Substances 0.000 description 1
- 229910052749 magnesium Inorganic materials 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 239000011259 mixed solution Substances 0.000 description 1
- 150000003014 phosphoric acid esters Chemical class 0.000 description 1
- CKRORYDHXIRZCH-UHFFFAOYSA-N phosphoric acid;dihydrate Chemical compound O.O.OP(O)(O)=O CKRORYDHXIRZCH-UHFFFAOYSA-N 0.000 description 1
- 230000035484 reaction time Effects 0.000 description 1
- 239000011734 sodium Substances 0.000 description 1
- 229910052708 sodium Inorganic materials 0.000 description 1
- 229910001415 sodium ion Inorganic materials 0.000 description 1
- 229910052979 sodium sulfide Inorganic materials 0.000 description 1
- GRVFOGOEDUUMBP-UHFFFAOYSA-N sodium sulfide (anhydrous) Chemical compound [Na+].[Na+].[S-2] GRVFOGOEDUUMBP-UHFFFAOYSA-N 0.000 description 1
- 229910001220 stainless steel Inorganic materials 0.000 description 1
- 239000010935 stainless steel Substances 0.000 description 1
- 230000003068 static effect Effects 0.000 description 1
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
- C01B25/18—Phosphoric acid
- C01B25/234—Purification; Stabilisation; Concentration
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D11/00—Solvent extraction
- B01D11/04—Solvent extraction of solutions which are liquid
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D9/00—Crystallisation
- B01D9/02—Crystallisation from solutions
-
- 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
- C01B25/18—Phosphoric acid
- C01B25/234—Purification; Stabilisation; Concentration
- C01B25/237—Selective elimination of impurities
- C01B25/2372—Anionic impurities, e.g. silica or boron compounds
-
- 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
- C01B25/18—Phosphoric acid
- C01B25/234—Purification; Stabilisation; Concentration
- C01B25/237—Selective elimination of impurities
- C01B25/238—Cationic impurities, e.g. arsenic compounds
-
- 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
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P20/00—Technologies relating to chemical industry
- Y02P20/10—Process efficiency
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Inorganic Chemistry (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Crystallography & Structural Chemistry (AREA)
Abstract
The invention belongs to the technical field of wet-process phosphoric acid purification, and relates to application of double-extraction physical impurity removal and suspension crystallization process technology in the field of wet-process phosphoric acid purification. The intermediate extraction utilizes concentrated phosphoric acid to carry out extraction, fine desulfurization and back extraction by adopting a high-selectivity anion extractant to obtain back extraction acid. And (3) desolventizing, decoloring and concentrating the back extraction acid to obtain the industrial-grade acid. The industrial grade acid adopts suspension crystallization, washing and dilution to obtain the high-purity food grade phosphoric acid. And (3) the final raffinate acid obtained by desolventizing the raffinate acid extracted in the middle and the post-treatment suspension crystallization mother liquor simultaneously return to pre-extraction for cation removal again. The invention adopts a wet process phosphoric acid purifying process route of double extraction and physical suspension crystallization impurity removal. The post-purification can produce phosphoric acid with different quality according to the process requirement, meanwhile, the low-temperature crystallization process scheme can reduce the dependence on materials, and the requirements can be met by common domestic 316L or 2205.
Description
Technical Field
The invention belongs to the technical field of wet-process phosphoric acid purification by a sulfuric acid method, and relates to a purification method for obtaining high-purity food-grade wet-process phosphoric acid.
Background
At present, the basic reserve of phosphorite in China is 32.4 hundred million tons, and it has been ascertained that phosphorite resources are distributed in 27 provinces (autonomous regions), but the distribution is centralized, and the distribution is mainly in five provinces of Hubei, sichuan, guizhou, yunnan and Hunan, the total reserve of phosphorite resources in five provinces exceeds 80%, but with the consumption of phosphorite resources, most of the phosphorite resources exhibit low grade characteristics, and the utilization of low grade phosphorite resources is greatly dependent on the technical level of wet phosphoric acid. The wet phosphoric acid has the characteristics of low-grade phosphorite utilization and low process energy consumption compared with the hot phosphoric acid, but has the inherent defects of high impurity content of phosphoric acid and high purification difficulty.
With the rise of new energy, the demand for high-purity phosphoric acid is increasing, so that the purification of phosphoric acid is particularly urgent. The phosphoric acid purifying method has a plurality of chemical precipitation, solvent extraction, crystallization, ion exchange and the like, and the solvent extraction is taken as a main flow process route in China at present, wherein the extraction process taking Vat Fu as a main flow process can continuously and industrially produce food grade phosphoric acid, and the Sichuan Dai and Hua Shi solvent extraction purifying processes meet the industrial phosphoric acid requirement.
Analysis of the wet phosphoric acid produced by collophanite in the Hubei area shows that the content of the iron-magnesium-aluminum sesquioxide in the acid is high, the MER value (the ratio of the sum of the percentage contents of the sesquioxide in the phosphoric acid to the percentage content of phosphorus pentoxide) is as high as 8 percent, and when dilute phosphoric acid is concentrated, the iron-magnesium-aluminum ion influence causes high acid viscosity, high energy consumption during concentration, difficult acid concentration and larger influence on the subsequent extraction efficiency improvement.
Disclosure of Invention
In order to solve the problems, the main purpose is to provide an extraction and suspension crystallization impurity removal technical route aiming at the defects existing in the prior extraction technology. Can effectively remove impurities under the condition of high impurity content of wet-process phosphoric acid to obtain high-purity wet-process purified phosphoric acid. The whole process has high extraction rate and low yield of raffinate acid, and is suitable for the new production technology of large-scale production.
The technical scheme comprises the following two procedures in series connection, and the technical method comprises the following steps:
1. and (3) a purification procedure:
(1) Step 1, extraction: and (3) sending the crude concentrated phosphoric acid to an extraction tower to carry out countercurrent extraction reaction with an extracting agent to obtain a light phase 1 and a heavy phase 1 containing phosphorus pentoxide.
(2) And 2, fine desulfurization: and (3) carrying out reaction fine desulfurization on the light phase 1 obtained in the step 1 of the extraction procedure by using a desulfurizing agent, and washing to obtain a light phase 2 and a heavy phase 2.
(3) Step 3, back extraction: and (3) back-extracting the light phase 1 obtained in the step 2 of the intermediate purification process by using desalted water to obtain a light phase 3 and a heavy phase 3. The light phase 3 returns to the purification and extraction process for cyclic reaction, and the heavy phase 3 is the extracted acid obtained after extraction.
(4) And 4, raffinate acid analysis: and (3) the heavy phase 1 obtained in the step (1) of the intermediate purification process is subjected to solvent analysis to obtain raffinate, and the raffinate is filtered to obtain clear liquid, and the clear liquid returns to a clear liquid tank of the pre-purification process to participate in the pre-extraction reaction. And delivering the filtered phosphorus-containing waste residue to a fertilizer process to produce the fertilizer.
(5) Step 5, stripping acid analysis: and (3) carrying out solvent analysis and concentration on the strip acid obtained in the step (3) in the intermediate purification process to obtain phosphoric acid without an extractant.
(6) And step 6, decoloring: and (3) decoloring the phosphoric acid obtained in the step (5) in the intermediate purification step by using activated carbon to obtain decolored acid.
(7) And 7, concentrating: and (3) carrying out flash evaporation on the decolorized acid obtained in the step (6) in the intermediate purification process to concentrate the acid to concentrated phosphoric acid with the phosphorus pentoxide content of 61-65%.
2. Post-purification procedure:
(1) Step 1, suspension crystallization: and (3) gradually cooling and crystallizing the concentrated phosphoric acid with the phosphorus pentoxide content of 61-65% obtained in the step 7 in the intermediate purification process, wherein the crystallization level is 2-4, so as to obtain high-purity phosphoric acid crystals and mother liquor.
(2) Step 2, centrifugal filtration washing: and (3) washing the phosphoric acid crystals obtained in the step (1) in the post-purification process by adopting 10-15% of pure phosphoric acid, and obtaining the high-purity phosphoric acid crystals with the phosphorus pentoxide content of 70% through centrifugal filtration.
(3) Step 3, dilution: and (3) diluting the high-purity phosphoric acid crystal with the phosphorus pentoxide content of 70% obtained in the step (2) in the post-purification working procedure by using desalted water to obtain the phosphoric acid with the phosphorus pentoxide content of 55% and above, or diluting to obtain the phosphoric acid with the phosphorus pentoxide content of 61.5% and above.
(4) Step 4, mother liquor treatment: and (3) returning the mother liquor obtained in the step 1 of the post-purification step to the pre-extraction step.
The invention has the beneficial effects that
1. According to the process scheme, sulfate radicals are removed without adding ore pulp in pretreatment, the operation is convenient to manage on site, phosphogypsum is not generated, and the acid loss is low.
2. The process has high extraction rate and less byproduct raffinate.
3. The reaction process does not need to add sodium sulfide for dearsenification, sodium ions are not introduced, the on-site system scaling cleaning is effectively reduced, and meanwhile, the on-site safety risk is reduced.
5. The post-purification can produce phosphoric acid with different quality according to the process requirement, meanwhile, the low-temperature crystallization process scheme can reduce the dependence on materials, and the requirements can be met by common domestic 316L or 2205.
Drawings
FIG. 1 is a flow chart of a wet process phosphoric acid suspension crystallization purification process.
Detailed Description
The extraction crystallization process of the wet-process phosphoric acid comprises the following steps:
(1) In a closed environment, the crude phosphoric acid is contacted and extracted with a pre-extractant to obtain the phosphoric acid with cations removed.
(2) Further carrying out contact extraction on the phosphoric acid with cations removed and a purifying extractant in a closed environment to obtain a light phase and a heavy phase; the light phase is treated by desulfurization, desalted water back extraction, decolorization and concentration to obtain concentrated phosphoric acid.
(3) And (3) cooling and slurrying the concentrated phosphoric acid, introducing the cooled phosphoric acid slurry into a suspension crystallizer, performing suspension crystallization to obtain phosphoric acid crystals, and diluting the phosphoric acid crystals to obtain a purified phosphoric acid product.
The closed environment is used for increasing the site safety risk and the solvent consumption while minimizing the exposure of the solvent to the air.
The concentration of the crude phosphoric acid in the step (1) is 30-50%, preferably 40-50%, and preferably 46-50%, and P is the concentration of the wet phosphoric acid 2 O 5 Wherein the impurities include fluorine, chlorine, sulfate, iron, aluminum, sodium, calcium, magnesium, and arsenic, and the content of fluorine is 0.7-1.1%, chlorine is 0.2-0.4%, and SO 4 2- 3.0-6.0％。
The extractant is one or more of phenyl phosphate, citrate, ketone and alcohol solvents.
The phenyl phosphate extractant comprises any one of triphenyl phosphate, tricresyl phosphate, diphenyl monooctyl phosphate, 3, 5-bis (isopropyl) phenyl diphenyl phosphate, tert-butylphenyl diphenyl phosphate, bis (4-nitrobenzene) phosphate, bis (2, 6-dimethylphenyl) phosphate and bis (2-isopropylphenyl) phenyl phosphate.
The citrate esters comprise any one of tributyl citrate, acetyl tributyl citrate, hard acyl citrate, acetyl trihexyl citrate, isopropyl citrate or butyryl trihexyl citrate.
The ketone solvent comprises any one of methyl isobutyl ketone, cyclohexanone, methyl ethyl ketone, 3-pentanone and 2-hexanone.
The alcohol solvent comprises any one of tertiary butanol, isoamyl alcohol, isobutyl alcohol, n-butyl alcohol, n-hexyl alcohol, n-octyl alcohol and tetradecyl alcohol.
The wet-process phosphoric acid is contacted and extracted with the extractant, and the compound containing the anionic impurities in the phosphoric acid is subjected to rapid and high-selective separation under the conditions of the concentration of the phosphoric acid and the extractant, so that the compound containing the anionic impurities is removed. The high selectivity means that under the condition of the phosphoric acid concentration and the condition of the extractant, the selectivity to the extractant is 80% -90%, and further, the selectivity to the extractant is 85% -95%. The rapid selectivity means 1 to 500s, further rapid selectivity means 1 to 350s, further rapid selectivity means 1 to 100s, further rapid selectivity means 1 to 120s, further rapid selectivity means 1 to 80s, further rapid selectivity means 1 to 60s, further rapid selectivity means 1 to 30s, further rapid selectivity means 1 to 20s.
In the wet process phosphoric acid purification process, solvent extraction is still a main technical means for preparing high-quality phosphoric acid. The extractant used is largely classified into phosphate esters, alkyl ketones, alkyl ethers, alkyl alcohols. In the extraction process, the distribution coefficient of phosphoric acid caused by the extractant can change along with the increase of the concentration of phosphoric acid, so that the extraction rate of phosphoric acid can also increase along with the increase of the concentration of phosphoric acid, thereby reducing the extraction efficiency.
The extractant and the extraction process provided by the application can form concentration matching with the high-concentration phosphoric acid contact process, so that the content of phosphoric acid in a heavy phase, namely raffinate acid, in the extraction process is reduced, and the loss of phosphoric acid in a light phase in the extraction process is reduced. In the process of carrying out back extraction on the light phase, the dosage of water of the back extractant realizes the effective separation of the light phase of the heavy phase, reduces the loss of phosphoric acid in the heavy phase at the moment, and enables the solvent in the light phase to be fully reused in the extractant.
In order to solve the problem of concentration matching with the mass concentration of the high-concentration phosphoric acid in the extraction process, the application adopts a mixed extractant formed by a plurality of extractants.
The phenyl phosphate extractant comprises any one of triphenyl phosphate, tricresyl phosphate, diphenyl monooctyl phosphate, 3, 5-bis (isopropyl) phenyl diphenyl phosphate, tert-butylphenyl diphenyl phosphate, bis (4-nitrobenzene) phosphate, bis (2, 6-dimethylphenyl) phosphate and bis (2-isopropylphenyl) phenyl phosphate.
The citrate esters comprise any one of tributyl citrate, acetyl tributyl citrate, hard acyl citrate, acetyl trihexyl citrate, isopropyl citrate or butyryl trihexyl citrate.
The ketone solvent comprises any one of methyl isobutyl ketone, cyclohexanone, methyl ethyl ketone, 3-pentanone and 2-hexanone.
The alcohol solvent comprises any one of tertiary butanol, isoamyl alcohol, isobutyl alcohol, n-butyl alcohol, n-hexyl alcohol, n-octyl alcohol and tetradecyl alcohol.
The extractant is phenyl phosphate solvent and ketone solvent in the volume ratio of 1:0.1 to 50, further preferably 1:1-40, further preferably 1:1-30; in the process of the formed mixture, mixing phenyl phosphate solvents and ketone solvents, and then carrying out high-speed mixing for 1min to 180min at the rotating speed of 400 to 1000 r/min;
preferably, in the process of the formed mixture, the phenyl phosphate solvent and the ketone solvent are mixed and then are mixed at a high speed for 1-120min at a rotating speed of 500-1000 r/min;
more preferably, in the process of forming the mixture, the phenyl phosphate solvent and the ketone solvent are mixed and then mixed at a high speed for 1-60min at a rotation speed of 500r/min, 600r/min, 700r/min, 800r/min and 900 r/min.
The extractant is phenyl phosphate solvent and alcohol solvent in the volume ratio of 1:0.1 to 50, further preferably 1:1-40, further preferably 1:1-30; in the process of the formed mixture, mixing phenyl phosphate solvents and alcohol solvents, and then carrying out high-speed mixing for 1min to 180min at the rotating speed of 400 to 1000 r/min;
preferably, in the process of the formed mixture, the phenyl phosphate solvent and the alcohol solvent are mixed and then are mixed at a high speed for 1-120min at a rotating speed of 500-1000 r/min;
more preferably, in the process of forming the mixture, the phenyl phosphate solvent and the ketone solvent are mixed and then mixed at a high speed for 1-60min at a rotation speed of 500r/min, 600r/min, 700r/min, 800r/min and 900 r/min.
The extractant is citrate ester solvent and ketone solvent in the volume ratio of 1:0.1 to 50, further preferably 1:1-40, further preferably 1:1-30; in the process of the formed mixture, mixing the citrate ester solvent and the ketone solvent, and then carrying out high-speed mixing for 1min to 180min at the rotating speed of 400 to 1000 r/min;
preferably, in the process of forming the mixture, the citrate ester solvent and the ketone solvent are mixed and then are mixed at a high speed for 1-120min at a rotating speed of 500-1000 r/min;
It is further preferable that in the process of forming the mixture, the citrate-type solvent and the ketone-type solvent are mixed and then high-speed mixed for 1-60min at a rotation speed of 500r/min, 600r/min, 700r/min, 800r/min, 900 r/min.
The extractant is citric acid ester solvent and alcohol solvent in the volume ratio of 1:0.1 to 50, further preferably 1:1-40, further preferably 1:1-30; in the process of the formed mixture, mixing the citrate ester solvent and the alcohol solvent, and then carrying out high-speed mixing for 1min to 180min at the rotating speed of 400 to 1000 r/min;
preferably, in the process of forming the mixture, the citrate solvent and the alcohol solvent are mixed and then are mixed at a high speed for 1-120min at a rotating speed of 500-1000 r/min;
more preferably, in the process of forming the mixture, the citrate-type solvent and the alcohol-type solvent are mixed and then mixed at a high speed for 1-60min at a rotation speed of 500r/min, 600r/min, 700r/min, 800r/min and 900 r/min.
The adding amount of the extractant is 1-5 times of the volume of the crude phosphoric acid, the concentrated phosphoric acid and the extractant are subjected to countercurrent contact extraction from top to bottom, the extractant is a continuous phase in the contact process, the phosphoric acid is a disperse phase, and the phosphoric acid is dispersed into a micro-particle state in the contact process, so that the contact area is increased.
The technical condition of overspeed mixing is adopted in the process of mixing the combined extracting agents, which is one of key technical characteristics for realizing extraction efficiency. The inventors found that the combined extractant was in a mutually embedded mixed state after overspeed stirring during the test. The color developed is basically relatively turbid or oil emulsion under the condition of no stirring or low-speed stirring below 300r/min, and the formed mixed liquid is relatively transparent after the overspeed mixing. Therefore, the novel mixed solution formed by the application can overcome the technical problems that the content of phosphoric acid is gradually increased in the process of adding phosphoric acid, the distribution coefficient difference is increased in the process of contacting the extraction solvent with phosphoric acid under the condition of low concentration, more phosphoric acid is carried away in heavy phase raffinate acid, and the concentration of phosphoric acid in a light phase is reduced. Meanwhile, the technical effect that the extraction agent still stabilizes the extraction efficiency after the back extraction process is circulated for a plurality of times is achieved.
The concentrated phosphoric acid and the extractant are subjected to countercurrent contact extraction from top to bottom, the concentrated phosphoric acid and/or the extractant are dispersed into a micro-particle state in the contact process, the contact area is increased, and the micro-particle state adopts any one of high-speed shearing dispersion, centrifugal dispersion and the like.
Before countercurrent contact is carried out for extraction, namely, concentrated phosphoric acid and an extracting agent respectively adopt any one form of high-speed shearing dispersion, centrifugal dispersion and the like to realize particle dispersion, and the granularity of the particle dispersion is respectively 10-500 microns, or 50-350 microns, or 100-200 microns. The degree of dispersion of the concentrated phosphoric acid and the extractant may be the same or different. The adoption of the micronization scheme and different dispersion degrees can indeed increase the specific surface area in the contact process and increase the mass transfer efficiency.
The addition amount of the extractant is 1-10 times of the volume of the concentrated phosphoric acid. More preferably, the extractant in the countercurrent contact extraction process is added in an amount of 1-6 times the volume of concentrated phosphoric acid. It is further preferred that the extractant according to the application is added in an amount of 1 to 4 times the volume of concentrated phosphoric acid in the countercurrent contact extraction process.
The extraction process of the application can realize the remarkable reduction of anions by carrying out one-time extraction, thereby realizing the reduction of workload, and the extraction of the part which is not completely extracted can be carried out again in the actual operation process. Meanwhile, the minimum amount of the extractant can realize the extraction with the wet phosphoric acid in the same mass ratio, and the extractant amount can be amplified to 1-2 times of the phosphoric acid amount for more sufficient extraction, but the actual effect is basically equivalent to the effect of the same mass. In the extraction process, the equivalent amount and 1-2 times of the dosage are calculated as the relative times of the flow of at least one phosphoric acid and at least one extractant in the contact extraction process.
The extraction reaction temperature is 35-60 ℃, more preferably 40-55 ℃, still more preferably 40-50 ℃ before or during the contact extraction of concentrated phosphoric acid and the extractant. The concentrated phosphoric acid and the extractant are preheated to the corresponding temperatures before contact extraction. The concentrated phosphoric acid and the extractant are subjected to contact extraction at the preset extraction environment temperature of 35-60 ℃, more preferably 40-55 ℃, still more preferably 40-50 ℃.
In the countercurrent contact extraction process, the extraction reaction temperature of the crude phosphoric acid and the extractant is 40-60 ℃, the pressure is 0.01-0.6 MPa, and the extraction time is 2-30min; preferably, the countercurrent contact is carried out, the extraction reaction temperature of the concentrated phosphoric acid and/or the purified extractant in the extraction process is 40-55 ℃, the pressure is 0.01-0.5MPa, and the extraction time is 2-20min;
it is further preferable that the extraction reaction temperature of the concentrated phosphoric acid and/or the purified extractant in the countercurrent contact extraction process is 40-50 ℃, the pressure is 0.01-0.3MPa, and the extraction time is 2-15min.
The extraction reaction time is the contact extraction time from the start of contact of concentrated phosphoric acid to the time of maintaining the suspension state of the extractant. In order to increase the suspension holding time for a certain time, the application realizes the contact extraction under micro negative pressure. After the contact extraction reaction, the effective separation of the light phase and the heavy phase can be realized.
The contact extraction reaction process is continuous, namely, concentrated phosphoric acid and an extracting agent are converted into flow relation continuously to enter an extraction environment in terms of mass relation, the phenomenon of light phase-heavy phase (oil phase-water phase) is realized after the contact extraction reaction is carried out in the environment, the extraction process is further completed, and the next process of realizing products and post-treatment is carried out.
Obtaining a light phase and a heavy phase after the extraction is completed;
the desulfurizing agent used in the desulfurizing process comprises any one of a dilute phosphoric acid solution of barium carbonate, a dilute phosphoric acid solution of calcium carbonate, a dilute phosphoric acid solution of barium bicarbonate and a dilute phosphoric acid solution of calcium bicarbonate; the mass concentration of the dilute phosphoric acid is 25-35%, and the mass fraction of the barium carbonate in the dilute phosphoric acid solution of the barium carbonate is 30-40%;
the barium carbonate, the calcium carbonate, the barium bicarbonate and the calcium bicarbonate are materials with the purity of more than 99.99 percent and are in micron order.
The volume ratio of the light phase to the desulfurizing agent is 8-10:1, a step of;
and the light phase 1 is desulfurized to obtain a light phase 2 and a heavy phase 2. And (3) resolving the heavy phase 1 and the heavy phase 2 to obtain raffinate, and filtering the raffinate to obtain a phosphoric acid and phosphate mixture with the mass concentration of 5-10%. The phosphate mixture is used for preparing fertilizer and realizing circulation.
And adding water into the light phase 2 for back extraction after desulfurization is completed, so as to obtain a heavy phase 3 (back extraction acid) and a light phase 3 (no-load solvent). The heavy phase 3 (back extraction acid) is purified phosphoric acid with anions removed, the mass concentration is 38-42%, and P is used 2 O 5 And (5) counting. The obtained light phase 3 (no-load solvent) is reused as a new extractant after being supplemented with a fresh extractant; the volume fraction of the light phase no-load solvent purifying extractant is 60-100%, preferably the volume fraction of no-load solvent in the purifying extractant is 70-95%, and more preferably the volume fraction of no-load solvent in the purifying extractant is 80-90%.
The empty solvent recovered by the method can be completely or partially used as an extracting agent to directly carry out countercurrent contact extraction with phosphoric acid. The micronization process and the extraction reaction conditions are still carried out in the countercurrent contact extraction process.
After the extraction of the effective part in the phosphoric acid is realized in the extraction process, the light phase after the desulfurization and back extraction can realize at least 95% of the original extractant by mass fraction, more preferably at least 98% of the original extractant by mass fraction, the distribution coefficient between the extractant and the gradually added concentrated phosphoric acid is not increased, and further the material after the back extraction can be stably extracted smoothly for the next link.
In order to save the enterprise cost, the light-phase no-load solvent realizes continuous operation, and the unavoidable no-load solvent can cause the problems of damage, impurity pollution and the like in the operation process. In order to realize the stability and the circulating effectiveness of the phosphoric acid index obtained by extraction, part of fresh extractant is supplemented in the circulating process of the no-load solvent, the formula proportion of the fresh extractant and the extractant in the raw materials is supplemented within 1-40% (volume fraction), and 3% of solvent is synchronously regenerated to remove impurities in each hour. Such as SO in the phosphoric acid index obtained by extraction 4 2- When the ion content exceeds 50ppm, SO is more preferable 4 2- When the ion content exceeds 35ppm, fresh extractant is added during the circulation of the empty solvent.
The heavy phase 3 (no-load solvent) is subjected to vacuum rectification, desolventizing and decoloring treatment, and desolventizing is carried out at the absolute pressure of 10-30KPaA and the temperature of 85-100 ℃.
Vacuum flash evaporating and concentrating the decolorized material and the desolventized material at 90-120 ℃ and absolute pressure of 10-25KPaA to obtain a mass concentration of 61-63%, and using P 2 O 5 Phosphoric acid in the meter.
The temperature of the cooling and slurrying in the step (1) in the step (2) is 35-50 ℃, and the stirring is carried out at 50-200r/min in the slurrying process, so that the phosphoric acid is formed into a uniformly mixed state under the stirring.
Furthermore, the temperature rise and slurrying are carried out at a temperature lower than 50 ℃ in the domestic 316L or 2205 material setting, so that metal ions in the stainless steel material can be effectively shielded, such as components of Fe, cr, ni and the like, are prevented from immersing into phosphoric acid again, and the temperature rise condition is an essential means of the application.
And (2) pulping and then introducing the slurry into a suspension crystallizer, wherein the suspension crystallization process adopts gradient cooling to 5-20 ℃, the stirring speed in the suspension crystallization process is 10-100r/min, preferably 10-50r/min, the gradient cooling stage number is 2-4, and the gradient cooling is equal gradient and/or non-equal gradient cooling.
The gradient cooling stage number is 2, the temperature of the pulpified phosphoric acid is reduced to 25 ℃ and then reduced to (10-15) +/-0.5 ℃ at 0.1-2.0 ℃/min, and the temperature is kept for 1-20min;
then cooling to (1-5) +/-0.5 ℃ at 0.1-2.0 ℃/min, and preserving heat for 1-10min.
The gradient cooling stage number is 3, the temperature of the pulpified phosphoric acid is reduced to 25 ℃ and then reduced to (15-20) +/-0.5 ℃ at 0.1-2.0 ℃/min, and the temperature is kept for 1-20min;
then cooling to (10-15) +/-0.5 ℃ at 0.1-2.0 ℃/min, and preserving heat for 1-20min;
then cooling to (1-5) +/-0.5 ℃ at 0.1-1.0 ℃/min, and preserving heat for 1-10min.
The gradient cooling stage number is 4, the temperature of the pulpified phosphoric acid is reduced to 25 ℃ and then reduced to (15-20) +/-0.5 ℃ at 0.1-2.0 ℃/min, and the temperature is kept for 1-20min;
then cooling to (10-15) +/-0.5 ℃ at 0.1-2.0 ℃/min, and preserving heat for 1-20min;
then cooling to (5-10) +/-0.5 ℃ at 0.1-1.0 ℃/min, and preserving heat for 1-20min;
then cooling to (1-5) +/-0.5 ℃ at 0.1-1.0 ℃/min, and preserving heat for 1-10min.
In the invention, after the pulping process, the obtained high-purity phosphoric acid is subjected to gradient or non-gradient cooling in a suspension crystallizer under the stirring condition, phosphoric acid crystal particles are suspended in the mother liquor and slowly grow in the mother liquor, and lamellar and blocky phosphoric acid crystal blocks are not formed under the stirring condition as in a static crystallization mode, but a large amount of fine crystal slurry is formed in the suspension mother liquor. During the gradual decrease in temperature, the crystals in the suspension slowly stabilize and form dense crystalline particles, removing impurity components.
The suspension crystallization equipment comprises a stirring and solid-liquid separation device, and the product from the suspension crystallization equipment is directly subjected to solid-liquid separation to separate the obtained fine crystal product from mother liquor.
The gradient cooling stage number of the invention is 2-4, which can be carried out in one suspension crystallization device or in a plurality of suspension crystallization devices.
Gradually cooling down in a suspension crystallizer. The process of crystallization in a plurality of suspension crystallization devices means that the crystallization is carried out by cooling at a certain temperature in one device, then the crystallization is carried out by transferring the crystallization into another device and cooling the crystallization relative to the previous device, and the like.
In the experiments carried out, it was found that the finer grains formed were larger after the multistage crystallization process. If the gradient cooling stage number is 4, the granularity is 800-1250 μm; when the gradient cooling stage number is 3, the granularity is 500-850 μm; when the gradient cooling stage number is 2, the granularity is 350-550 μm. The larger the granularity is, the easier the solid-liquid separation is performed in the washing process, and the crystallization product is reduced to enter the phosphoric acid mother liquor.
And (3) carrying out suspension crystallization in the step (2), and then carrying out solid-liquid separation to obtain phosphoric acid crystals and phosphoric acid mother liquor, wherein the phosphoric acid mother liquor returns to crude phosphoric acid, and an extraction process is carried out.
The phosphoric acid crystal is washed by adopting low-temperature desalted water as a washing liquid, and the temperature of the low-temperature desalted water is controlled to be 2-10 ℃; returning filtrate from the washing process to the suspension crystallizer in the step (2); the washed phosphoric acid product is heated to 30-35 ℃ and then prepared into phosphoric acid with different concentrations.
In some embodiments, the low temperature desalted water is at a temperature of 5 to 10 ℃, and the temperature difference between the low temperature desalted water and the obtained crystal is small, so that the problem of recrystallization is further reduced. The obtained washing filtrate is directly added into the suspension crystallizer at low temperature, which is helpful for reducing the temperature of phosphoric acid after pulping and reducing the heat loss.
The recovered low-temperature filtrate is supplemented to the step (1) for heating and slurrying, and supersaturated solution of liquid phase is formed in the solution in the step (1), so that crystallization is realized in the suspension crystallizer after slurrying.
In the present invention, fe, mg, al, as, ca, na is exemplified, and the metal ion concentration in the phosphoric acid obtained is less than 10ppm. The total metal ion content is less than 50ppm, preferably less than 40ppm.
For a better understanding of the present invention, the following examples are further illustrated by the following description of the present invention, using wet process phosphoric acid dihydrate crude phosphoric acid as raw material phosphoric acid, the crude phosphoric acid index is shown in table 1, but the present invention is not limited to the following examples.
TABLE 1 phosphoric acid parameter index
Example 1
The wet process phosphoric acid purification process is carried out by adopting the process and the crude phosphoric acid with the number of 5, and the specific steps are as follows:
Configuration of the extractant: the volume ratio of the citric acid hard ester to the tetradecanol is 1:28, and mixing at 600r/min for 10min to form transparent suspension.
Desulfurizing agent: the mass concentration of the dilute phosphoric acid solution of the barium carbonate is 40%, and the mass fraction of the barium carbonate in the dilute phosphoric acid solution of the barium carbonate is 30%.
1. Extraction and purification process:
(1) Step 1, extraction: the temperature in the purifying extraction tower is 45+/-5 ℃, the pressure in the extraction tower is 0.01-0.05MPa, crude phosphoric acid and an extracting agent are respectively preheated to 45+/-5 ℃, wet phosphoric acid and an extracting solvent are respectively fed into the extraction tower from the upper part and the lower part of the extraction tower together according to the volume ratio of 1:2 for contact extraction, a turntable tower is adopted for emulsification and dispersion in the extraction process, and after 5min of contact reaction, the light phase 1 and the heavy phase 1 containing phosphorus pentoxide are collected.
(2) And 2, fine desulfurization: and (3) carrying out reaction fine desulfurization on the light phase 1 obtained in the step 1 of the extraction and purification process by using a desulfurizing agent, wherein the volume ratio of the light phase 1 to the desulfurizing agent is 12:1, washing to obtain a light phase 2 and a heavy phase 2.
(3) Step 3, back extraction: and (3) back-extracting the light phase 2 obtained in the step 2 of the extraction and purification process by using desalted water to obtain a light phase 3 and a heavy phase 3. The light phase 3 is supplemented with 12 percent of extractant with volume fraction, and the extractant returns to the purification and extraction process for cyclic reaction, and the heavy phase 3 is stripping acid with mass concentration of 40-42 percent obtained after intermediate purification.
(4) And 4, raffinate acid analysis: mixing the heavy phase 1 obtained in the step 1 of the extraction and purification process with the heavy phase 2 obtained in the step 2, then resolving and removing the solvent to obtain raffinate acid, and carrying out extraction reaction on the liquid phase obtained by filtering the raffinate acid. And delivering the filtered phosphorus-containing waste residue to a fertilizer process to produce the fertilizer.
(5) Step 5, stripping acid analysis: and (3) carrying out vacuum rectification and desolventizing on the stripping acid with the mass concentration of 40-42% obtained in the extraction and purification step 3 at the temperature of 10-30KPaA and the temperature of 85-100 ℃ to obtain the phosphoric acid with the concentration of 42-50% without solvent.
(6) And step 6, decoloring: and (3) decoloring the phosphoric acid obtained in the step (5) in the extraction and purification process by using activated carbon to obtain decolored acid.
(7) And 7, concentrating: and (3) carrying out vacuum flash evaporation and concentration on the decolorized acid obtained in the step 6 in the extraction and purification process at 90-120 ℃ under the absolute pressure of 10-25KPaA to obtain concentrated phosphoric acid with the phosphorus pentoxide content of 61-65%.
2. And (3) a recrystallization purification step:
(1) Step 1, suspension crystallization: cooling the concentrated phosphoric acid with 61-65% phosphorus pentoxide content obtained in the step 7 of the extraction and purification process to 30-35 ℃, and pulping and mixing uniformly under 150 r/min; cooling the pulpified phosphoric acid to 25-30 ℃, introducing the cooled phosphoric acid into a suspension crystallizer, and performing suspension crystallization at the stirring speed of 30r/min to obtain slurry, wherein the built-in material of the suspension crystallizer equipment is domestic 316L.
The gradient cooling stage number is 4, the temperature of the pulpified phosphoric acid is reduced to 25 ℃ and then reduced to 22+/-0.5 ℃ at 1.0 ℃/min, and the temperature is kept for 5min;
then cooling to 18+/-0.5 ℃ at 0.8 ℃/min, and preserving heat for 5min;
then cooling to 14+/-0.5 ℃ at 0.4 ℃/min, and preserving heat for 5min;
then cooling to 5+/-0.5 ℃ at 0.2 ℃/min, and preserving heat for 5min.
(2) Step 2, centrifugal filtration washing: and (2) washing the phosphoric acid crystals and the phosphoric acid mother liquor obtained in the step (1) of the recrystallization purification process by adopting 12% of high-purity phosphoric acid, wherein the high-purity phosphoric acid is phosphoric acid with impurities less than 50ppb, and obtaining the high-purity phosphoric acid crystals with phosphorus pentoxide content of 61.5-70% through centrifugal filtration. Sending the separated phosphoric acid mother liquor into a cyclone for fine crystal recovery, sending the recovered fine crystal into crude phosphoric acid for extraction, and discharging the fine crystal mother liquor as waste liquid;
(3) Step 3, dilution: and (3) purifying the phosphoric acid crystal with 61.5-70% of phosphorus pentoxide content obtained in the step 2. Washing the crystals by using desalted water at a low temperature of 5-10 ℃ as a washing liquid, and returning filtrate in the washing process to the suspension crystallizer in the step (2); washing with washing liquid, heating to 30-35 deg.c in a melting tank, and diluting to obtain phosphoric acid product.
Example 2
The wet process phosphoric acid purification process is carried out by adopting the process and the crude phosphoric acid with the number of 5, and the specific steps are as follows:
configuration of the extractant: t-butylphenyl diphenyl phosphate and methyl ethyl ketone in a volume ratio of 1:25, and mixing at 600r/min for 10min to form transparent suspension.
Desulfurizing agent: the mass concentration of the dilute phosphoric acid solution of the calcium carbonate is 30%, and the mass fraction of the calcium carbonate in the dilute phosphoric acid solution of the calcium carbonate is 35%.
1. Extraction and purification process:
(1) Step 1, extraction: the temperature in the purifying extraction tower is 45+/-5 ℃, the pressure in the extraction tower is 0.01-0.05MPa, crude phosphoric acid and an extracting agent are respectively preheated to 45+/-5 ℃, wet phosphoric acid and an extracting solvent are respectively fed into the extraction tower from the upper part and the lower part of the extraction tower together according to the volume ratio of 1:2 for contact extraction, a turntable tower is adopted for emulsification and dispersion in the extraction process, and after the contact reaction is carried out for 11min, the light phase 1 and the heavy phase 1 containing phosphorus pentoxide are collected.
(2) And 2, fine desulfurization: and (3) carrying out reaction fine desulfurization on the light phase 1 obtained in the step 1 of the extraction and purification process by using a desulfurizing agent, wherein the volume ratio of the light phase 1 to the desulfurizing agent is 10:1, washing to obtain a light phase 2 and a heavy phase 2.
(3) Step 3, back extraction: and (3) back-extracting the light phase 2 obtained in the step 2 of the extraction and purification process by using desalted water at the temperature of 5 ℃ to obtain a light phase 3 and a heavy phase 3. The light phase 3 is supplemented with 40 percent of extractant by volume fraction, and the extractant returns to the purification and extraction process for cyclic reaction, and the heavy phase 3 is stripping acid with the mass concentration of 40-42 percent obtained after intermediate purification.
(4) And 4, raffinate acid analysis: mixing the heavy phase 1 obtained in the step 1 of the extraction and purification process with the heavy phase 2 obtained in the step 2, then resolving and removing the solvent to obtain raffinate acid, and carrying out extraction reaction on the liquid phase obtained by filtering the raffinate acid. And delivering the filtered phosphorus-containing waste residue to a fertilizer process to produce the fertilizer.
And (3) carrying out vacuum rectification and desolventizing on the stripping acid with the mass concentration of 40-42% obtained in the extraction and purification step 3 at the temperature of 10-30KPaA and the temperature of 85-100 ℃ to obtain the phosphoric acid with the concentration of 42-50% without solvent.
(6) And step 6, decoloring: and (3) decoloring the phosphoric acid obtained in the step (5) in the extraction and purification process by using activated carbon to obtain decolored acid.
(7) And 7, concentrating: and (3) carrying out vacuum flash evaporation and concentration on the decolorized acid obtained in the step 6 in the extraction and purification process at 90-120 ℃ under the absolute pressure of 10-25KPaA to obtain concentrated phosphoric acid with the phosphorus pentoxide content of 61-65%.
2. And (3) a recrystallization purification step:
(1) Step 1, suspension crystallization: cooling the concentrated phosphoric acid with 61-65% phosphorus pentoxide content obtained in the step 7 of the extraction and purification process to 30-35 ℃, and pulping and mixing uniformly under 150 r/min; cooling the pulpified phosphoric acid to 25-30 ℃, introducing the cooled phosphoric acid into a suspension crystallizer, and performing suspension crystallization at the stirring speed of 30r/min to obtain slurry, wherein the built-in material of the suspension crystallizer equipment is domestic 316L.
The gradient cooling stage number is 3, the temperature of the pulpified phosphoric acid is reduced to 25 ℃, then the temperature is reduced to 20+/-0.5 ℃ at 0.8 ℃/min, and the temperature is kept for 15min;
then cooling to 12+/-0.5 ℃ at 0.8 ℃/min, and preserving heat for 10min;
then cooling to 2+/-0.5 ℃ at 0.8 ℃/min, and preserving heat for 5min.
And (2) washing the phosphoric acid crystals and the phosphoric acid mother liquor obtained in the step (1) of the recrystallization purification process by adopting 12% of high-purity phosphoric acid, wherein the high-purity phosphoric acid is phosphoric acid with impurities less than 50ppb, and obtaining the high-purity phosphoric acid crystals with phosphorus pentoxide content of 61.5-70% through centrifugal filtration. Sending the separated phosphoric acid mother liquor into a cyclone for fine crystal recovery, sending the recovered fine crystal into crude phosphoric acid for extraction, and discharging the fine crystal mother liquor as waste liquid;
(3) Step 3, dilution: and (3) purifying the phosphoric acid crystal with 61.5-70% of phosphorus pentoxide content obtained in the step 2. Washing the crystals by using desalted water at a low temperature of 5-10 ℃ as a washing liquid, and returning filtrate in the washing process to the suspension crystallizer in the step (2); washing with washing liquid, heating to 30-35 deg.c in a melting tank, and diluting to obtain phosphoric acid product.
Example 3
The wet process phosphoric acid purification process is carried out by adopting the process and the crude phosphoric acid with the number of 5, and the specific steps are as follows:
configuration of the extractant: the volume ratio of the citric acid hard ester to the cyclohexanone is 1:18, and mixing at 600r/min for 10min to form transparent suspension.
Desulfurizing agent: the mass concentration of the dilute phosphoric acid solution of the calcium carbonate is 30%, and the mass fraction of the calcium carbonate in the dilute phosphoric acid solution of the calcium carbonate is 35%.
1. Extraction and purification process:
(1) The temperature in the extraction purification extraction tower is 45+/-5 ℃, the pressure in the extraction tower is 0.01-0.05MPa, crude phosphoric acid and an extractant are respectively preheated to 45+/-5 ℃, wet phosphoric acid and an extraction solvent are respectively fed into the extraction tower from the upper part and the lower part of the extraction tower together according to the volume ratio of 1:2 for contact extraction, a turntable tower is adopted for emulsification and dispersion in the extraction process, and the light phase 1 and the heavy phase 1 containing phosphorus pentoxide are collected after the contact reaction is carried out for 7 min.
(2) And 2, fine desulfurization: and (3) carrying out reaction fine desulfurization on the light phase 1 obtained in the step 1 of the extraction and purification process by using a desulfurizing agent, wherein the volume ratio of the light phase 1 to the desulfurizing agent is 10:1, washing to obtain a light phase 2 and a heavy phase 2.
(3) Step 3, back extraction: and (3) back-extracting the light phase 2 obtained in the step 2 of the extraction and purification process by using desalted water at the temperature of 5 ℃ to obtain a light phase 3 and a heavy phase 3. The light phase 3 is supplemented with 40 percent of extractant by volume fraction, and the extractant returns to the purification and extraction process for cyclic reaction, and the heavy phase 3 is stripping acid with the mass concentration of 40-42 percent obtained after intermediate purification.
(4) And 4, raffinate acid analysis: mixing the heavy phase 1 obtained in the step 1 of the extraction and purification process with the heavy phase 2 obtained in the step 2, then resolving and removing the solvent to obtain raffinate acid, and carrying out extraction reaction on the liquid phase obtained by filtering the raffinate acid. And delivering the filtered phosphorus-containing waste residue to a fertilizer process to produce the fertilizer.
And (3) carrying out vacuum rectification and desolventizing on the stripping acid with the mass concentration of 40-42% obtained in the extraction and purification step 3 at the temperature of 10-30KPaA and the temperature of 85-100 ℃ to obtain the phosphoric acid with the concentration of 42-50% without solvent.
(6) And step 6, decoloring: and (3) decoloring the phosphoric acid obtained in the step (5) in the extraction and purification process by using activated carbon to obtain decolored acid.
(7) And 7, concentrating: and (3) carrying out vacuum flash evaporation and concentration on the decolorized acid obtained in the step 6 in the extraction and purification process at 90-120 ℃ under the absolute pressure of 10-25KPaA to obtain concentrated phosphoric acid with the phosphorus pentoxide content of 61-65%.
2. And (3) a recrystallization purification step:
(1) Step 1, suspension crystallization: cooling the concentrated phosphoric acid with 61-65% phosphorus pentoxide content obtained in the step 7 of the extraction and purification process to 30-35 ℃, and pulping and mixing uniformly under 150 r/min; cooling the pulpified phosphoric acid to 25-30 ℃, introducing the cooled phosphoric acid into a suspension crystallizer, and performing suspension crystallization at the stirring speed of 30r/min to obtain slurry, wherein the built-in material of the suspension crystallizer equipment is domestic 316L.
The gradient cooling stage number is 3, the temperature of the pulpified phosphoric acid is reduced to 25 ℃, then the temperature is reduced to 20+/-0.5 ℃ at 0.5 ℃ per minute, and the temperature is kept for 15 minutes;
then cooling to 10+/-0.5 ℃ at 0.5 ℃/min, and preserving heat for 10min;
then cooling to 2+/-0.5 ℃ at 0.5 ℃/min, and preserving heat for 5min.
And (2) washing the phosphoric acid crystals and the phosphoric acid mother liquor obtained in the step (1) of the recrystallization purification process by adopting 12% of high-purity phosphoric acid, wherein the high-purity phosphoric acid is phosphoric acid with impurities less than 50ppb, and obtaining the high-purity phosphoric acid crystals with phosphorus pentoxide content of 61.5-70% through centrifugal filtration. Sending the separated phosphoric acid mother liquor into a cyclone for fine crystal recovery, sending the recovered fine crystal into crude phosphoric acid for extraction, and discharging the fine crystal mother liquor as waste liquid;
(3) Step 3, dilution: and (3) purifying the phosphoric acid crystal with 61.5-70% of phosphorus pentoxide content obtained in the step 2. Washing the crystals by using desalted water at a low temperature of 5-10 ℃ as a washing liquid, and returning filtrate in the washing process to the suspension crystallizer in the step (2); washing with washing liquid, heating to 30-35 deg.c in a melting tank, and diluting to obtain phosphoric acid product.
Note that the yield of the present invention refers to the product acid/feed phosphoric acid and is characterized by the efficiency of phosphoric acid purification.
Claims (22)
1. The extraction crystallization process of the wet phosphoric acid is characterized by comprising the following steps of:
(1) Countercurrent contact extraction is carried out on the crude phosphoric acid and an extracting agent in a closed environment, so as to obtain extracted phosphoric acid;
(2) And (3) heating and slurrying the phosphoric acid extracted in the step (1), introducing the phosphoric acid into a suspension crystallizer, performing suspension crystallization to obtain phosphoric acid crystals, and washing and melting the phosphoric acid crystals to obtain a phosphoric acid product.
2. The process according to claim 1, wherein the crude phosphoric acid in step (1) has a concentration of 30-50%, preferably 40-50%, preferably 46-50%, by P 2 O 5 Wherein the impurities include fluorine 0.7-1.1%, chlorine 0.2-0.4%, SO 4 2- 3.0-6.0%。
3. The process for the extractive crystallization of wet-process phosphoric acid according to claim 1, wherein the extractant is one or more of phenyl phosphates, citric acid esters, ketones, and alcohol solvents.
4. The process for the extractive crystallization of wet-process phosphoric acid according to claim 3, wherein the phenyl phosphate extractant comprises any one of triphenyl phosphate, tricresyl phosphate, diphenyl monooctyl phosphate, 3, 5-bis (isopropyl) phenyl diphenyl phosphate, t-butylphenyl diphenyl phosphate, bis (4-nitrobenzene) phosphate, bis (2, 6-dimethylphenyl) phosphate, and bis (2-isopropylphenyl) phenyl phosphate.
5. The process for the extractive crystallization of wet-process phosphoric acid according to claim 3, wherein the citrate esters comprise any one of tri-n-butyl citrate, acetyl tributyl citrate, stearyl citrate, acetyl tri-hexyl citrate, isopropyl citrate, and butyryl tri-hexyl citrate.
6. The process for the extractive crystallization of wet-process phosphoric acid according to claim 3, wherein the ketone solvent comprises any one of methyl isobutyl ketone, cyclohexanone, methyl ethyl ketone, 3-pentanone and 2-hexanone.
7. The process for extractive crystallization of wet-process phosphoric acid according to claim 3, wherein the alcohol solvent comprises any one of t-butanol, isoamyl alcohol, isobutanol, n-butanol, n-hexanol, n-octanol, and tetradecyl alcohol.
8. The process for the extractive crystallization of wet-process phosphoric acid according to any one of claims 3 to 7, wherein the extractant is phenyl phosphate solvent and ketone solvent in a volume ratio of 1:0.1-50, wherein in the process of the formed mixture, phenyl phosphate solvents and ketone solvents are mixed and then are mixed at a high speed for 1-180 min at a rotating speed of 400-1000 r/min;
Preferably, in the process of the formed mixture, the phenyl phosphate solvent and the ketone solvent are mixed and then are mixed at a high speed for 1-120min at a rotating speed of 500-1000 r/min;
more preferably, in the process of forming the mixture, the phenyl phosphate solvent and the ketone solvent are mixed and then mixed at a high speed for 1-60min at a rotation speed of 500r/min, 600r/min, 700r/min, 800r/min and 900 r/min.
9. The process for the extractive crystallization of wet-process phosphoric acid according to any one of claims 3 to 7, wherein the extractant is phenyl phosphate solvent and alcohol solvent in a volume ratio of 1:0.1-50, wherein in the process of the formed mixture, phenyl phosphate solvents and alcohol solvents are mixed and then are mixed at a high speed for 1-180 min at a rotating speed of 400-1000 r/min;
preferably, in the process of the formed mixture, the phenyl phosphate solvent and the alcohol solvent are mixed and then are mixed at a high speed for 1-120min at a rotating speed of 500-1000 r/min;
more preferably, in the process of forming the mixture, the phenyl phosphate solvent and the ketone solvent are mixed and then mixed at a high speed for 1-60min at a rotation speed of 500r/min, 600r/min, 700r/min, 800r/min and 900 r/min.
10. The process for the extractive crystallization of wet-process phosphoric acid according to any one of claims 3 to 7, wherein the extractant is a citrate solvent and a ketone solvent in a volume ratio of 1:0.1-50, wherein in the process of the formed mixture, the citric acid ester solvent and the ketone solvent are mixed and then are mixed at a high speed for 1-180 min at a rotating speed of 400-1000 r/min;
preferably, in the process of forming the mixture, the citrate ester solvent and the ketone solvent are mixed and then are mixed at a high speed for 1-120min at a rotating speed of 500-1000 r/min;
it is further preferable that in the process of forming the mixture, the citrate-type solvent and the ketone-type solvent are mixed and then high-speed mixed for 1-60min at a rotation speed of 500r/min, 600r/min, 700r/min, 800r/min, 900 r/min.
11. The process for the extractive crystallization of wet-process phosphoric acid according to any one of claims 3 to 7, wherein the extractant is a citrate solvent and an alcohol solvent in a volume ratio of 1:0.1-50, wherein in the process of the formed mixture, the citric acid ester solvent and the alcohol solvent are mixed and then are mixed at a high speed for 1-180 min at a rotating speed of 400-1000 r/min;
Preferably, in the process of forming the mixture, the citrate solvent and the alcohol solvent are mixed and then are mixed at a high speed for 1-120min at a rotating speed of 500-1000 r/min;
more preferably, in the process of forming the mixture, the citrate-type solvent and the alcohol-type solvent are mixed and then mixed at a high speed for 1-60min at a rotation speed of 500r/min, 600r/min, 700r/min, 800r/min and 900 r/min.
12. The process for extracting and crystallizing wet phosphoric acid as claimed in claim 1, wherein the addition amount of the extractant is 1-5 times of the volume of the crude phosphoric acid, the concentrated phosphoric acid is countercurrent contact-extracted with the extractant from top to bottom, and the crude phosphoric acid and the extractant are fully contacted and reacted for dispersing particles in the contact process.
13. The process for extracting and crystallizing wet phosphoric acid according to claim 1, wherein the extraction reaction temperature of the crude phosphoric acid and the extractant in the countercurrent contact extraction process is 40-60 ℃, the pressure is 0.01-0.6 mpa, and the extraction time is 2-30min; preferably, the countercurrent contact is carried out, the extraction reaction temperature of the concentrated phosphoric acid and/or the purified extractant in the extraction process is 40-55 ℃, the pressure is 0.01-0.5MPa, and the extraction time is 2-20min;
It is further preferable that the extraction reaction temperature of the concentrated phosphoric acid and/or the purified extractant in the countercurrent contact extraction process is 45-50 ℃, the pressure is 0.01-0.3MPa, and the extraction time is 2-15min.
14. The process for the extraction and crystallization of wet-process phosphoric acid according to claim 1, wherein a light phase and a heavy phase are obtained after the extraction is completed;
the desulfurizing agent used in the desulfurizing process comprises any one of a dilute phosphoric acid solution of barium carbonate, a dilute phosphoric acid solution of calcium carbonate, a dilute phosphoric acid solution of barium bicarbonate and a dilute phosphoric acid solution of calcium bicarbonate; the mass concentration of the dilute phosphoric acid is 25-35%, and the mass fraction of the barium carbonate in the dilute phosphoric acid solution of the barium carbonate is 30-40%;
the volume ratio of the light phase to the desulfurizing agent is 8-10:1, a step of;
the heavy phase obtained after extraction and the heavy phase obtained after desulfurization are resolved by raffinate, after the resolution is finished, the solution phase part returns to the crude phosphoric acid to participate in extraction, and the solid phase part is used as phosphate to be produced.
15. The process according to claim 14, wherein the light phase is stripped by adding desalted water after desulfurization to obtain heavy phase stripping acid and light phase no-load solvent;
the light-phase no-load solvent is reused as a purifying extractant after being supplemented with a fresh extractant; the volume fraction of the light phase empty solvent purifying extractant is 60-100%, preferably the empty solvent accounts for 60-90% of the volume fraction of the purifying extractant, and more preferably the back extraction liquid accounts for 80-90% of the volume fraction of the purifying extractant.
16. The process for extracting and crystallizing wet-process phosphoric acid as claimed in claim 15, wherein the heavy phase extraction acid is desolventized by vacuum distillation under the condition of desolventizing at an absolute pressure of 10-30KPaA and a temperature of 85-100 ℃ after the activated carbon decolorization treatment;
and carrying out vacuum flash evaporation on the decolorized material and the material obtained after solvent removal at the temperature of 90-120 ℃ and the absolute pressure of 10-25KPaA to obtain the phosphoric acid with the concentration of 61-65%.
17. The wet process phosphoric acid purification process according to claim 1, wherein the slurry temperature in the step (2) is 30-35 ℃, and the slurry is stirred at 10-50r/min during the cooling slurry process. The wet process phosphoric acid purification process according to claim 17, wherein in the step (2), slurry is introduced into a suspension crystallizer, the suspension crystallization process is cooled to 5-20 ℃ by gradient, the stirring speed in the suspension crystallization process is 10-50r/min, the gradient cooling stage number is 2-4, and the gradient cooling stage number is equal gradient and/or non-equal gradient cooling.
18. The wet process phosphoric acid suspension crystallization purification process according to claim 18, wherein the gradient cooling stage number is 2, the slurried phosphoric acid is cooled to 25 ℃ and then cooled to (10-15) ± 0.5 ℃ at 0.1-2.0 ℃/min, and the temperature is kept for 1-20min;
Then cooling to (1-5) +/-0.5 ℃ at 0.1-2.0 ℃/min, and preserving heat for 1-10min.
19. The wet process phosphoric acid suspension crystallization purification process according to claim 18, wherein the gradient cooling stage number is 3, the slurried phosphoric acid is cooled to 25 ℃ and then cooled to (15-20) ± 0.5 ℃ at 0.1-2.0 ℃/min, and the temperature is kept for 1-20min;
then cooling to (10-15) +/-0.5 ℃ at 0.1-2.0 ℃/min, and preserving heat for 1-20min;
then cooling to (1-5) +/-0.5 ℃ at 0.1-1.0 ℃/min, and preserving heat for 1-10min.
20. The wet process phosphoric acid suspension crystallization purification process according to claim 18, wherein the gradient cooling stage number is 4, the slurried phosphoric acid is cooled to 25 ℃ and then cooled to (15-20) ± 0.5 ℃ at 0.1-2.0 ℃/min, and the temperature is kept for 1-20min;
then cooling to (10-15) +/-0.5 ℃ at 0.1-2.0 ℃/min, and preserving heat for 1-20min;
then cooling to (5-10) +/-0.5 ℃ at 0.1-1.0 ℃/min, and preserving heat for 1-20min;
then cooling to (1-5) +/-0.5 ℃ at 0.1-1.0 ℃/min, and preserving heat for 1-10min.
21. The wet process phosphoric acid suspension crystallization purification process according to claim 18, wherein in the step (2), after suspension crystallization, phosphoric acid crystals and phosphoric acid mother liquor are obtained through solid-liquid separation, and the phosphoric acid mother liquor is returned to crude phosphoric acid for extraction process.
22. The wet process phosphoric acid suspension crystallization purification process according to claim 18, wherein phosphoric acid crystals are washed by using low temperature desalted water as a washing liquid, and the temperature of the low temperature desalted water is controlled to be 2-10 ℃; returning filtrate from the washing process to the suspension crystallizer in the step (2); the washed phosphoric acid product is heated to 30-35 ℃ and then prepared into phosphoric acid with different concentrations.
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| CN117049501A (en) * | 2023-09-12 | 2023-11-14 | 厦门大学 | Method for preparing electronic grade phosphoric acid by ultrasonic-assisted melt crystallization |
| CN117720079A (en) * | 2023-12-11 | 2024-03-19 | 安徽金轩科技有限公司 | High-efficiency impurity removal method and system for phosphoric acid |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN117049501A (en) * | 2023-09-12 | 2023-11-14 | 厦门大学 | Method for preparing electronic grade phosphoric acid by ultrasonic-assisted melt crystallization |
| CN117720079A (en) * | 2023-12-11 | 2024-03-19 | 安徽金轩科技有限公司 | High-efficiency impurity removal method and system for phosphoric acid |
| CN117720079B (en) * | 2023-12-11 | 2024-05-17 | 安徽金轩科技有限公司 | High-efficiency impurity removal method and system for phosphoric acid |
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