CN116902936A - Process for extracting impurities in wet phosphoric acid - Google Patents
Process for extracting impurities in wet phosphoric acid Download PDFInfo
- Publication number
- CN116902936A CN116902936A CN202310580118.5A CN202310580118A CN116902936A CN 116902936 A CN116902936 A CN 116902936A CN 202310580118 A CN202310580118 A CN 202310580118A CN 116902936 A CN116902936 A CN 116902936A
- Authority
- CN
- China
- Prior art keywords
- phosphoric acid
- extraction
- extractant
- solvent
- phosphate
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
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- NBIIXXVUZAFLBC-UHFFFAOYSA-N Phosphoric acid Chemical compound OP(O)(O)=O NBIIXXVUZAFLBC-UHFFFAOYSA-N 0.000 title claims abstract description 534
- 229910000147 aluminium phosphate Inorganic materials 0.000 title claims abstract description 267
- 238000000034 method Methods 0.000 title claims abstract description 124
- 239000012535 impurity Substances 0.000 title claims abstract description 40
- 238000000605 extraction Methods 0.000 claims abstract description 232
- 239000002253 acid Substances 0.000 claims abstract description 68
- 150000001768 cations Chemical class 0.000 claims abstract description 23
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims abstract description 15
- 238000006477 desulfuration reaction Methods 0.000 claims abstract description 15
- 230000023556 desulfurization Effects 0.000 claims abstract description 15
- 229910052751 metal Inorganic materials 0.000 claims abstract description 11
- 239000002184 metal Substances 0.000 claims abstract description 11
- 239000011737 fluorine Substances 0.000 claims abstract description 10
- 229910052731 fluorine Inorganic materials 0.000 claims abstract description 10
- 150000001450 anions Chemical class 0.000 claims abstract description 8
- 239000000460 chlorine Substances 0.000 claims abstract description 8
- 229910052742 iron Inorganic materials 0.000 claims abstract description 8
- 229910052782 aluminium Inorganic materials 0.000 claims abstract description 7
- 239000011777 magnesium Substances 0.000 claims abstract description 7
- 229910052749 magnesium Inorganic materials 0.000 claims abstract description 7
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 claims abstract description 6
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 claims abstract description 6
- ZAMOUSCENKQFHK-UHFFFAOYSA-N Chlorine atom Chemical compound [Cl] ZAMOUSCENKQFHK-UHFFFAOYSA-N 0.000 claims abstract description 5
- 229910052801 chlorine Inorganic materials 0.000 claims abstract description 5
- PXGOKWXKJXAPGV-UHFFFAOYSA-N Fluorine Chemical compound FF PXGOKWXKJXAPGV-UHFFFAOYSA-N 0.000 claims abstract 3
- 239000002904 solvent Substances 0.000 claims description 100
- 239000007788 liquid Substances 0.000 claims description 53
- ZWEHNKRNPOVVGH-UHFFFAOYSA-N 2-Butanone Chemical compound CCC(C)=O ZWEHNKRNPOVVGH-UHFFFAOYSA-N 0.000 claims description 48
- LRHPLDYGYMQRHN-UHFFFAOYSA-N N-Butanol Chemical compound CCCCO LRHPLDYGYMQRHN-UHFFFAOYSA-N 0.000 claims description 42
- PHTQWCKDNZKARW-UHFFFAOYSA-N isoamylol Chemical compound CC(C)CCO PHTQWCKDNZKARW-UHFFFAOYSA-N 0.000 claims description 42
- 239000003795 chemical substances by application Substances 0.000 claims description 40
- KBPLFHHGFOOTCA-UHFFFAOYSA-N 1-Octanol Chemical compound CCCCCCCCO KBPLFHHGFOOTCA-UHFFFAOYSA-N 0.000 claims description 38
- 238000006243 chemical reaction Methods 0.000 claims description 38
- ZSIAUFGUXNUGDI-UHFFFAOYSA-N hexan-1-ol Chemical compound CCCCCCO ZSIAUFGUXNUGDI-UHFFFAOYSA-N 0.000 claims description 36
- JHIVVAPYMSGYDF-UHFFFAOYSA-N cyclohexanone Chemical compound O=C1CCCCC1 JHIVVAPYMSGYDF-UHFFFAOYSA-N 0.000 claims description 34
- QQZOPKMRPOGIEB-UHFFFAOYSA-N 2-Oxohexane Chemical compound CCCCC(C)=O QQZOPKMRPOGIEB-UHFFFAOYSA-N 0.000 claims description 32
- ZXEKIIBDNHEJCQ-UHFFFAOYSA-N isobutanol Chemical compound CC(C)CO ZXEKIIBDNHEJCQ-UHFFFAOYSA-N 0.000 claims description 32
- FDPIMTJIUBPUKL-UHFFFAOYSA-N pentan-3-one Chemical compound CCC(=O)CC FDPIMTJIUBPUKL-UHFFFAOYSA-N 0.000 claims description 32
- HLZKNKRTKFSKGZ-UHFFFAOYSA-N tetradecan-1-ol Chemical compound CCCCCCCCCCCCCCO HLZKNKRTKFSKGZ-UHFFFAOYSA-N 0.000 claims description 32
- 238000002156 mixing Methods 0.000 claims description 31
- DKGAVHZHDRPRBM-UHFFFAOYSA-N Tert-Butanol Chemical compound CC(C)(C)O DKGAVHZHDRPRBM-UHFFFAOYSA-N 0.000 claims description 30
- AYJRCSIUFZENHW-UHFFFAOYSA-L barium carbonate Chemical compound [Ba+2].[O-]C([O-])=O AYJRCSIUFZENHW-UHFFFAOYSA-L 0.000 claims description 28
- 239000003337 fertilizer Substances 0.000 claims description 24
- -1 amino, carboxyl Chemical group 0.000 claims description 21
- 230000003009 desulfurizing effect Effects 0.000 claims description 19
- 239000000243 solution Substances 0.000 claims description 18
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 18
- NTIZESTWPVYFNL-UHFFFAOYSA-N Methyl isobutyl ketone Chemical compound CC(C)CC(C)=O NTIZESTWPVYFNL-UHFFFAOYSA-N 0.000 claims description 16
- UIHCLUNTQKBZGK-UHFFFAOYSA-N Methyl isobutyl ketone Natural products CCC(C)C(C)=O UIHCLUNTQKBZGK-UHFFFAOYSA-N 0.000 claims description 16
- 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
- 150000002576 ketones Chemical class 0.000 claims description 16
- 239000000203 mixture Substances 0.000 claims description 16
- 238000004458 analytical method Methods 0.000 claims description 15
- 239000003085 diluting agent Substances 0.000 claims description 14
- 238000001914 filtration Methods 0.000 claims description 14
- 239000011259 mixed solution Substances 0.000 claims description 14
- OJMIONKXNSYLSR-UHFFFAOYSA-N phosphorous acid Chemical compound OP(O)O OJMIONKXNSYLSR-UHFFFAOYSA-N 0.000 claims description 14
- CMPQUABWPXYYSH-UHFFFAOYSA-N phenyl phosphate Chemical compound OP(O)(=O)OC1=CC=CC=C1 CMPQUABWPXYYSH-UHFFFAOYSA-N 0.000 claims description 13
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 claims description 12
- 229910019142 PO4 Inorganic materials 0.000 claims description 9
- 239000000463 material Substances 0.000 claims description 8
- 239000010452 phosphate Substances 0.000 claims description 8
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 claims description 6
- 238000001704 evaporation Methods 0.000 claims description 6
- 229940035429 isobutyl alcohol Drugs 0.000 claims description 6
- 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 6
- 239000011574 phosphorus Substances 0.000 claims description 6
- 229910052698 phosphorus Inorganic materials 0.000 claims description 6
- OYPRJOBELJOOCE-UHFFFAOYSA-N Calcium Chemical compound [Ca] OYPRJOBELJOOCE-UHFFFAOYSA-N 0.000 claims description 5
- 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 5
- 239000000654 additive Substances 0.000 claims description 5
- 239000011575 calcium Substances 0.000 claims description 5
- 229910052791 calcium Inorganic materials 0.000 claims description 5
- 238000007865 diluting Methods 0.000 claims description 5
- JBTWLSYIZRCDFO-UHFFFAOYSA-N ethyl methyl carbonate Chemical compound CCOC(=O)OC JBTWLSYIZRCDFO-UHFFFAOYSA-N 0.000 claims description 5
- 230000008020 evaporation Effects 0.000 claims description 5
- NBIIXXVUZAFLBC-UHFFFAOYSA-K phosphate Chemical compound [O-]P([O-])([O-])=O NBIIXXVUZAFLBC-UHFFFAOYSA-K 0.000 claims description 5
- 238000004062 sedimentation Methods 0.000 claims description 5
- 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 5
- 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 claims description 4
- BBMCTIGTTCKYKF-UHFFFAOYSA-N 1-heptanol Chemical compound CCCCCCCO BBMCTIGTTCKYKF-UHFFFAOYSA-N 0.000 claims description 4
- VTYYLEPIZMXCLO-UHFFFAOYSA-L Calcium carbonate Chemical compound [Ca+2].[O-]C([O-])=O VTYYLEPIZMXCLO-UHFFFAOYSA-L 0.000 claims description 4
- KRKNYBCHXYNGOX-UHFFFAOYSA-K Citrate Chemical compound [O-]C(=O)CC(O)(CC([O-])=O)C([O-])=O KRKNYBCHXYNGOX-UHFFFAOYSA-K 0.000 claims description 4
- 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 4
- 229910052785 arsenic Inorganic materials 0.000 claims description 4
- 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 4
- 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 4
- CCZMQYGSXWZFKI-UHFFFAOYSA-N 1-chloro-4-dichlorophosphoryloxybenzene Chemical compound ClC1=CC=C(OP(Cl)(Cl)=O)C=C1 CCZMQYGSXWZFKI-UHFFFAOYSA-N 0.000 claims description 3
- 229910018072 Al 2 O 3 Inorganic materials 0.000 claims description 3
- 239000007983 Tris buffer Substances 0.000 claims description 3
- HPXRVTGHNJAIIH-UHFFFAOYSA-N cyclohexanol Chemical compound OC1CCCCC1 HPXRVTGHNJAIIH-UHFFFAOYSA-N 0.000 claims description 3
- 238000004519 manufacturing process Methods 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
- 238000004064 recycling Methods 0.000 claims description 3
- OPNUROKCUBTKLF-UHFFFAOYSA-N 1,2-bis(2-methylphenyl)guanidine Chemical compound CC1=CC=CC=C1N\C(N)=N\C1=CC=CC=C1C OPNUROKCUBTKLF-UHFFFAOYSA-N 0.000 claims description 2
- YZBOZNXACBQJHI-UHFFFAOYSA-N 1-dichlorophosphoryloxyethane Chemical compound CCOP(Cl)(Cl)=O YZBOZNXACBQJHI-UHFFFAOYSA-N 0.000 claims description 2
- KUQZVISZELWDNZ-UHFFFAOYSA-N 3-aminopropyl dihydrogen phosphate Chemical compound NCCCOP(O)(O)=O KUQZVISZELWDNZ-UHFFFAOYSA-N 0.000 claims description 2
- OSBJUINXNAJWND-UHFFFAOYSA-N CC1=CC=CC=C1OP(=O)(O)Cl Chemical compound CC1=CC=CC=C1OP(=O)(O)Cl OSBJUINXNAJWND-UHFFFAOYSA-N 0.000 claims description 2
- 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 claims description 2
- AMQJEAYHLZJPGS-UHFFFAOYSA-N N-Pentanol Chemical compound CCCCCO AMQJEAYHLZJPGS-UHFFFAOYSA-N 0.000 claims description 2
- JKIJEFPNVSHHEI-UHFFFAOYSA-N Phenol, 2,4-bis(1,1-dimethylethyl)-, phosphite (3:1) Chemical compound CC(C)(C)C1=CC(C(C)(C)C)=CC=C1OP(OC=1C(=CC(=CC=1)C(C)(C)C)C(C)(C)C)OC1=CC=C(C(C)(C)C)C=C1C(C)(C)C JKIJEFPNVSHHEI-UHFFFAOYSA-N 0.000 claims description 2
- QAOWNCQODCNURD-UHFFFAOYSA-L Sulfate Chemical compound [O-]S([O-])(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-L 0.000 claims description 2
- 230000000996 additive effect Effects 0.000 claims description 2
- 239000005456 alcohol based solvent Substances 0.000 claims description 2
- RQNWIZPPADIBDY-UHFFFAOYSA-N arsenic atom Chemical compound [As] RQNWIZPPADIBDY-UHFFFAOYSA-N 0.000 claims description 2
- UCVMQZHZWWEPRC-UHFFFAOYSA-L barium(2+);hydrogen carbonate Chemical compound [Ba+2].OC([O-])=O.OC([O-])=O UCVMQZHZWWEPRC-UHFFFAOYSA-L 0.000 claims description 2
- AYJRCSIUFZENHW-DEQYMQKBSA-L barium(2+);oxomethanediolate Chemical compound [Ba+2].[O-][14C]([O-])=O AYJRCSIUFZENHW-DEQYMQKBSA-L 0.000 claims description 2
- ZAFAJHDHPYDVCN-UHFFFAOYSA-N butanoic acid;phosphoric acid Chemical compound OP(O)(O)=O.CCCC(O)=O ZAFAJHDHPYDVCN-UHFFFAOYSA-N 0.000 claims description 2
- NKWPZUCBCARRDP-UHFFFAOYSA-L calcium bicarbonate Chemical compound [Ca+2].OC([O-])=O.OC([O-])=O NKWPZUCBCARRDP-UHFFFAOYSA-L 0.000 claims description 2
- 229910000020 calcium bicarbonate Inorganic materials 0.000 claims description 2
- 229910000019 calcium carbonate Inorganic materials 0.000 claims description 2
- HSZCIIHXQDBPOI-UHFFFAOYSA-N fluorourea Chemical compound NC(=O)NF HSZCIIHXQDBPOI-UHFFFAOYSA-N 0.000 claims description 2
- 229910052736 halogen Inorganic materials 0.000 claims description 2
- 150000002367 halogens Chemical group 0.000 claims description 2
- 125000002887 hydroxy group Chemical group [H]O* 0.000 claims description 2
- 239000003350 kerosene Substances 0.000 claims description 2
- 239000005453 ketone based solvent Substances 0.000 claims description 2
- MIABSAQIFYEDJP-UHFFFAOYSA-N perfluorodecyl phosphate Chemical compound OP(O)(=O)OCCC(F)(F)C(F)(F)C(F)(F)C(F)(F)C(F)(F)C(F)(F)C(F)(F)C(F)(F)F MIABSAQIFYEDJP-UHFFFAOYSA-N 0.000 claims description 2
- 150000003013 phosphoric acid derivatives Chemical class 0.000 claims description 2
- 229910052708 sodium Inorganic materials 0.000 claims description 2
- 239000011734 sodium Substances 0.000 claims description 2
- 125000001424 substituent group Chemical group 0.000 claims description 2
- 238000006467 substitution reaction Methods 0.000 claims description 2
- 125000003698 tetramethyl group Chemical group [H]C([H])([H])* 0.000 claims description 2
- 125000003396 thiol group Chemical group [H]S* 0.000 claims description 2
- CNUJLMSKURPSHE-UHFFFAOYSA-N trioctadecyl phosphite Chemical compound CCCCCCCCCCCCCCCCCCOP(OCCCCCCCCCCCCCCCCCC)OCCCCCCCCCCCCCCCCCC CNUJLMSKURPSHE-UHFFFAOYSA-N 0.000 claims description 2
- SJHCUXCOGGKFAI-UHFFFAOYSA-N tripropan-2-yl phosphite Chemical compound CC(C)OP(OC(C)C)OC(C)C SJHCUXCOGGKFAI-UHFFFAOYSA-N 0.000 claims description 2
- WGKLOLBTFWFKOD-UHFFFAOYSA-N tris(2-nonylphenyl) phosphite Chemical compound CCCCCCCCCC1=CC=CC=C1OP(OC=1C(=CC=CC=1)CCCCCCCCC)OC1=CC=CC=C1CCCCCCCCC WGKLOLBTFWFKOD-UHFFFAOYSA-N 0.000 claims description 2
- BHYQWBKCXBXPKM-UHFFFAOYSA-N tris[3-bromo-2,2-bis(bromomethyl)propyl] phosphate Chemical compound BrCC(CBr)(CBr)COP(=O)(OCC(CBr)(CBr)CBr)OCC(CBr)(CBr)CBr BHYQWBKCXBXPKM-UHFFFAOYSA-N 0.000 claims description 2
- CGSLYBDCEGBZCG-UHFFFAOYSA-N Octicizer Chemical compound C=1C=CC=CC=1OP(=O)(OCC(CC)CCCC)OC1=CC=CC=C1 CGSLYBDCEGBZCG-UHFFFAOYSA-N 0.000 claims 1
- 230000015572 biosynthetic process Effects 0.000 claims 1
- ITVPBBDAZKBMRP-UHFFFAOYSA-N chloro-dioxido-oxo-$l^{5}-phosphane;hydron Chemical compound OP(O)(Cl)=O ITVPBBDAZKBMRP-UHFFFAOYSA-N 0.000 claims 1
- KPGXUAIFQMJJFB-UHFFFAOYSA-H tungsten hexachloride Chemical compound Cl[W](Cl)(Cl)(Cl)(Cl)Cl KPGXUAIFQMJJFB-UHFFFAOYSA-H 0.000 claims 1
- 238000000746 purification Methods 0.000 abstract description 72
- 239000000725 suspension Substances 0.000 abstract description 26
- 238000002425 crystallisation Methods 0.000 abstract description 20
- 230000008025 crystallization Effects 0.000 abstract description 20
- 239000012452 mother liquor Substances 0.000 abstract description 11
- 238000005516 engineering process Methods 0.000 abstract description 2
- DLYUQMMRRRQYAE-UHFFFAOYSA-N tetraphosphorus decaoxide Chemical compound O1P(O2)(=O)OP3(=O)OP1(=O)OP2(=O)O3 DLYUQMMRRRQYAE-UHFFFAOYSA-N 0.000 description 34
- 238000001816 cooling Methods 0.000 description 32
- MUBZPKHOEPUJKR-UHFFFAOYSA-N Oxalic acid Chemical compound OC(=O)C(O)=O MUBZPKHOEPUJKR-UHFFFAOYSA-N 0.000 description 15
- 239000013078 crystal Substances 0.000 description 15
- 238000005406 washing Methods 0.000 description 12
- TVMXDCGIABBOFY-UHFFFAOYSA-N n-Octanol Natural products CCCCCCCC TVMXDCGIABBOFY-UHFFFAOYSA-N 0.000 description 10
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 9
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 8
- YCKRFDGAMUMZLT-UHFFFAOYSA-N Fluorine atom Chemical compound [F] YCKRFDGAMUMZLT-UHFFFAOYSA-N 0.000 description 7
- 239000002367 phosphate rock Substances 0.000 description 7
- 238000000926 separation method Methods 0.000 description 7
- ZFOZVQLOBQUTQQ-UHFFFAOYSA-N Tributyl citrate Chemical compound CCCCOC(=O)CC(O)(C(=O)OCCCC)CC(=O)OCCCC ZFOZVQLOBQUTQQ-UHFFFAOYSA-N 0.000 description 6
- 230000000694 effects Effects 0.000 description 6
- 235000021317 phosphate Nutrition 0.000 description 6
- 238000003756 stirring Methods 0.000 description 6
- CPLXHLVBOLITMK-UHFFFAOYSA-N Magnesium oxide Chemical compound [Mg]=O CPLXHLVBOLITMK-UHFFFAOYSA-N 0.000 description 5
- 125000002091 cationic group Chemical group 0.000 description 5
- 235000006408 oxalic acid Nutrition 0.000 description 5
- 229920002401 polyacrylamide Polymers 0.000 description 5
- 239000000047 product Substances 0.000 description 5
- 239000002994 raw material Substances 0.000 description 5
- 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 description 4
- 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 description 4
- 239000004804 Butyryltrihexylcitrate Substances 0.000 description 4
- 150000001875 compounds Chemical class 0.000 description 4
- 125000004122 cyclic group Chemical group 0.000 description 4
- 238000010790 dilution Methods 0.000 description 4
- 239000012895 dilution Substances 0.000 description 4
- 239000002002 slurry Substances 0.000 description 4
- 239000007787 solid Substances 0.000 description 4
- 239000002699 waste material Substances 0.000 description 4
- 239000002310 Isopropyl citrate Substances 0.000 description 3
- 239000006185 dispersion Substances 0.000 description 3
- 238000009826 distribution Methods 0.000 description 3
- 239000000839 emulsion Substances 0.000 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 description 3
- 235000019300 isopropyl citrate Nutrition 0.000 description 3
- 239000000395 magnesium oxide Substances 0.000 description 3
- 238000002360 preparation method Methods 0.000 description 3
- 238000003825 pressing Methods 0.000 description 3
- 238000004537 pulping Methods 0.000 description 3
- 238000000638 solvent extraction Methods 0.000 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 description 3
- 239000004480 active ingredient Substances 0.000 description 2
- 125000000129 anionic group Chemical group 0.000 description 2
- 230000007547 defect Effects 0.000 description 2
- 230000001804 emulsifying effect 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
- 229910021645 metal ion Inorganic materials 0.000 description 2
- 239000002245 particle Substances 0.000 description 2
- 238000011084 recovery Methods 0.000 description 2
- 238000005292 vacuum distillation Methods 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 1
- JSHMCUNOMIZJDJ-UHFFFAOYSA-N butanoyl dihydrogen phosphate Chemical compound CCCC(=O)OP(O)(O)=O JSHMCUNOMIZJDJ-UHFFFAOYSA-N 0.000 description 1
- 239000006227 byproduct Substances 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
- 229910052799 carbon Inorganic materials 0.000 description 1
- 238000009388 chemical precipitation Methods 0.000 description 1
- 150000001860 citric acid derivatives Chemical class 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
- 238000001514 detection method Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000005342 ion exchange Methods 0.000 description 1
- UQSXHKLRYXJYBZ-UHFFFAOYSA-N iron oxide Inorganic materials [Fe]=O UQSXHKLRYXJYBZ-UHFFFAOYSA-N 0.000 description 1
- 238000011031 large-scale manufacturing process Methods 0.000 description 1
- AXZKOIWUVFPNLO-UHFFFAOYSA-N magnesium;oxygen(2-) Chemical compound [O-2].[Mg+2] AXZKOIWUVFPNLO-UHFFFAOYSA-N 0.000 description 1
- 230000014759 maintenance of location Effects 0.000 description 1
- 239000011859 microparticle Substances 0.000 description 1
- TWNQGVIAIRXVLR-UHFFFAOYSA-N oxo(oxoalumanyloxy)alumane Chemical compound O=[Al]O[Al]=O TWNQGVIAIRXVLR-UHFFFAOYSA-N 0.000 description 1
- NDLPOXTZKUMGOV-UHFFFAOYSA-N oxo(oxoferriooxy)iron hydrate Chemical compound O.O=[Fe]O[Fe]=O NDLPOXTZKUMGOV-UHFFFAOYSA-N 0.000 description 1
- LPLPPIFARDQDDL-UHFFFAOYSA-N phenyl (2-propan-2-ylphenyl) hydrogen phosphate Chemical group CC(C)C1=CC=CC=C1OP(O)(=O)OC1=CC=CC=C1 LPLPPIFARDQDDL-UHFFFAOYSA-N 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
- 239000002244 precipitate Substances 0.000 description 1
- 239000012716 precipitator Substances 0.000 description 1
- 238000011085 pressure filtration Methods 0.000 description 1
- 230000002035 prolonged effect Effects 0.000 description 1
- 230000035484 reaction time Effects 0.000 description 1
- 230000008929 regeneration Effects 0.000 description 1
- 238000011069 regeneration method Methods 0.000 description 1
- 230000000717 retained effect Effects 0.000 description 1
- 239000011833 salt mixture Substances 0.000 description 1
- 238000007789 sealing Methods 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
- 238000003860 storage Methods 0.000 description 1
- 239000013589 supplement Substances 0.000 description 1
- 230000001360 synchronised 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
- B01D11/0488—Flow sheets
-
- 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
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D11/00—Solvent extraction
- B01D2011/002—Counter-current extraction
-
- 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
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Inorganic Chemistry (AREA)
- Chemical Kinetics & Catalysis (AREA)
Abstract
The invention provides a process for extracting impurities in wet-process phosphoric acid, which is applied to the field of wet-process phosphoric acid purification by combining a suspension crystallization process technology. The main steps are pre-extraction, namely, wet phosphoric acid is firstly subjected to removal of metal cations such as iron, magnesium, aluminum and the like by adopting a high-selectivity cation extractant. Concentrating the decationized acid. 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. 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. After a large amount of metal cations are removed in the pre-extraction process, the viscosity of the acid is reduced, the steam consumption can be saved when the concentration of phosphoric acid is improved, and the removal of anions such as fluorine, chlorine, sulfate radical and the like is facilitated by the improvement of the concentration of the acid.
Description
Technical Field
The invention belongs to the technical field of wet phosphoric acid purification by a sulfuric acid method, and relates to a method for purifying phosphoric acid by a wet method.
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 wet phosphoric acid produced by collophanite in 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%, 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. Further, the removal of anions also has a problem of difficult removal.
Disclosure of Invention
In order to solve the problems, the main purpose is to provide a double-extraction 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 of the process comprises the following three working procedures in series connection, and the process comprises the following steps:
1. pre-purification procedure:
(1) Step 1, pre-sedimentation: and (3) delivering 30% -50% of the crude phosphoric acid into a settling tank, settling by adding a settling agent (polyacrylamide) to obtain clear acid, overflowing to a clear liquid tank, performing filter pressing solid-liquid separation on the lower silt acid, delivering the solid to a fertilizer workshop to produce fertilizer, and returning clear liquid to the clear liquid tank.
(2) Step 2, pre-extraction: and (3) sending the clear liquid obtained in the step (1) and the pre-extractant into an extraction tower, and carrying out extraction reaction in a countercurrent contact mode to obtain a light phase (1) and a heavy phase (2).
(3) Step 3, desolventizing: and (3) desolventizing the light phase 1 obtained in the step (2) to obtain cationic salt, and producing fertilizer or further purifying.
(4) Step 4, desolventizing: concentrating the heavy phase obtained in the step 2 to obtain 53-55% concentrated phosphoric acid.
2. Intermediate purification process:
(1) Step 1, extraction: and (3) delivering the 53-55% concentrated phosphoric acid obtained in the step (4) of the pre-purification process to a purification tower and purifying an extracting agent for countercurrent extraction reaction to obtain a light phase 2 and a heavy phase 2 containing phosphorus pentoxide.
(2) And 2, fine desulfurization: and (3) carrying out reaction fine desulfurization on the light phase 2 obtained in the step 1 of the intermediate purification process by using a desulfurizing agent, and washing to obtain a light phase 3 and a heavy phase 3. The desulfurizing agent is dilute phosphoric acid solution with barium carbonate.
(3) Step 3, back extraction: and (3) carrying out back extraction on the light phase 2 obtained in the step 2 of the intermediate purification process by using desalted water to obtain a light phase 4 and a heavy phase 4. The light phase 4 returns to the purification and extraction process for cyclic reaction, and the heavy phase 4 is the stripping acid with the concentration of 38-42% obtained after intermediate purification.
(4) And 4, raffinate acid analysis: and (3) the heavy phase 2 obtained in the step (1) in 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 in 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 the phosphoric acid with 42-50% of concentration without solvent.
(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%.
3. 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, and adopting a multi-stage crystallization process to obtain high-purity phosphoric acid crystals and mother liquor, wherein the crystallization stage number is controlled to be 2-6, preferably 2-4.
(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.
4. The metal cations are removed in an extraction mode in the pretreatment, so that the method can be suitable for a high-impurity system of raw material acid, in particular to phosphoric acid of a high-aluminum high-magnesium system in a semi-water two-water wet phosphoric acid process.
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.
6. After a large amount of metal cations are removed in the pre-extraction process, the viscosity of the acid is reduced, the steam consumption can be saved when the concentration of phosphoric acid is improved, and meanwhile, the removal and recovery of fluorine are facilitated due to the improvement of the acid concentration.
Drawings
FIG. 1 is a process flow diagram of the present invention.
Detailed Description
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.
The wet phosphoric acid purifying process includes the following steps:
(1) In a closed environment, contacting and extracting crude phosphoric acid with a pre-extracting agent to obtain 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 desulfurized, desalted water is back extracted, decolorized and concentrated 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 crude phosphoric acid concentration in step (1) is 30-50%, preferably the wet phosphoric acid concentration is 40-50%, preferably 46-50% wet phosphoric acid, P 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％、Fe 2 O 3 0.4-0.8％、Al 2 O 3 1.5-3.5％、NaO 0.3-0.4％、CaO 0.3-0.4％、MgO 1.5-3.5％、As 10-50ppm。
The content of the metal cations which are difficult to remove in the process directly leads to the quality of the wet-process phosphoric acid to be an unqualified product in the food field and the industrial field. The content of the metal cations in the phosphoric acid which is difficult to remove causes the viscosity of the phosphoric acid to be pure within a certain range (15-35 m.pas), and the viscosity can continuously increase or have certain fluctuation with the prolonged storage time, but the viscosity cannot be reduced. What is more troublesome to those skilled in the art is that the presence of this viscosity significantly increases the steam usage of the phosphoric acid concentration process. For example, from a wet phosphoric acid concentration of 46-50% and a sesquioxide content of less than 1.0%, a steam amount of 0.40-0.50t/m is required per volume of dilute acid concentration when concentrating to 58-62% 3 (steam consumption); whereas the amount of steam required for concentration per volume of dilute acid is 0.53-0.63t/m at a sesquioxide content of more than 2.0% and less than 4.0% 3 The method comprises the steps of carrying out a first treatment on the surface of the And the steam amount required for concentration per volume of dilute acid is 0.55-0.75t/m when the sesquioxide content is more than 4.0% and less than 6.0% 3 . The sesquioxide comprises detection indexes which are the most basic of the technicians in the field, and is ferric oxide, magnesium oxide and aluminum oxide. Those skilled in the art generally take these three together as influencing factors that influence the properties of the product.
It is further unacceptable to those skilled in the art that the presence of this viscosity also results in the appearance of fluorine content during the phosphoric acid concentration process. This is because the wet-process phosphoric acid contains a certain amount of fluorine content, and fluorine-containing precipitates formed in the concentration process further affect the quality of the wet-process phosphoric acid, and reduce the fluorine recovery rate.
And (3) pre-extracting clear liquid obtained after the crude phosphoric acid in the step (1) is settled by a settling agent (specifically polyacrylamide).
The pre-extractant comprises any one or more of phosphate, phosphite and substituted phosphate, and the substituent comprises any one or more of halogen substitution, amino, carboxyl, sulfhydryl and hydroxyl.
The pre-extractant is selected from any one of bis (2, 2-trifluoroethyl) phosphite, tris (2, 2-trifluoroethyl) phosphite, triisopropyl phosphite, tristearyl phosphite, trimethylolpropane phosphite, tris (nonylphenyl) phosphite and tris (2, 4-di-tert-butylphenyl) phosphite;
or any one selected from 4-chlorophenyl dichlorophosphate, phenyl tetramethylene hexafluorophosphate, mono [2- (perfluorooctyl) ethyl ] phosphate, o-tolyl chlorophosphate, tetramethyl fluorourea hexafluorophosphate, tris (tribromoneopentyl) phosphate, ethyl dichlorophosphate, 3-aminopropyl monophosphate, butyric acid phosphate and dodecyl phosphate diethanolamine phosphate.
The present application is not exhaustive and alkyl phosphates, alkyl phosphites, alkyl halogenated phosphates, which achieve the pre-extraction effect of the present application, are all within the scope of the present application.
The crude phosphoric acid is contacted and extracted with at least one pre-extractant, under the condition of the pre-extractant, the compound containing metal cation impurities in the phosphoric acid is subjected to rapid and high-selectivity separation under the condition of the concentration of the crude phosphoric acid and the condition of the pre-extractant, and then the compound containing metal cation impurities is removed. The high selectivity means that under the condition of the phosphoric acid concentration and the condition of the pre-extractant, the selectivity of the pre-extractant is 90% -100%, and further, the selectivity of the pre-extractant is 95% -100%. The rapid selectivity is 1-500s, further rapid selectivity is 1-300s, further rapid selectivity is 1-210s, further rapid selectivity is 1-120s, and further rapid selectivity is 1-60s.
The pre-extraction agent is diluted by a diluent to obtain a mixed solution with the mass concentration of 1-50wt%, or preferably diluted by the diluent to obtain a mixed solution with the mass concentration of 1-40wt%, or preferably diluted by the diluent to obtain a mixed solution with the mass concentration of 3-30wt%;
the process of diluting the pre-extracting agent by adopting the diluent is to add the pre-extracting agent into the diluent, and then carry out high-speed miscibility for 1-60min at the rotating speed of 400-1000 r/min;
the rotating speed in the mixing process is 500r/min-1000r/min, and the high-speed mixing time is 3-40min;
it is further preferable that the rotation speed during the mixing process is 500r/min, 700r/min, or 900r/min, and the high-speed mixing time is 5-30min.
The diluent is selected from any one or more of n-butanol, isoamyl alcohol, amyl alcohol, cyclohexanol, hexanol, heptanol, octanol and sulfonated kerosene;
in the extraction process in the step (1), the wet phosphoric acid and at least one pre-extractant are subjected to countercurrent contact extraction, wherein the mass ratio of the crude phosphoric acid to the at least one pre-extractant is 1:1-10; it is further preferred that the mass ratio of wet phosphoric acid to at least one pre-extractant is 1:1-6; it is further preferred that the mass ratio of wet phosphoric acid to at least one pre-extractant is 1:1-4.
The concentration of the solvent in the mixed solution relative to the diluent is that under the condition of the concentration range of the solvent (or the pre-extractant), the high-efficiency extraction can be realized, and the diluent mainly plays a role in dispersing the pre-extractant, and further realizes the dispersion of the solvent in the phosphoric acid environment, so that the high-efficiency extraction of phosphoric acid is realized.
The extraction process of the application can realize the remarkable reduction of metal ions in one extraction, and realize the reduction of workload, and the extraction of the part which is not completely extracted can be performed 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 can be amplified to 2-3 times of the phosphoric acid 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 the amount are 2-3 times, and the relative times of the flow of at least one phosphoric acid and at least one extractant in the contact extraction process are calculated.
The extraction reaction temperature of the crude phosphoric acid and at least one solvent in the extraction process is 20-60 ℃ and the pressure is 0.1-0.6MPa; it is further preferred that the extraction reaction temperature of the wet phosphoric acid and at least one solvent in the countercurrent contact extraction process is 20-50 ℃ and the pressure is 0.1-0.6MPa;
It is further preferred that the extraction reaction temperature of the wet phosphoric acid and the at least one solvent in the countercurrent contact extraction process is 30-45 ℃ and the pressure is 0.1-0.6MPa.
The extraction reaction time is the contact extraction time between at least one wet phosphoric acid and at least one solvent from the contact to the time of maintaining the emulsion. In order to increase the retention time of the emulsion for a certain time, the application realizes contact extraction under the sealing. 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, at least one wet phosphoric acid and at least one solvent are converted into flow relation continuity in a mass relation and enter an extraction environment, 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.
In the application, the heavy phase generated after extraction is concentrated to obtain the phosphoric acid with the mass fraction of 53-55% and removed cations; and adding dilute phosphoric acid and oxalic acid into the light phase obtained after extraction to remove metal ions, obtaining an empty pre-extractant, separating out a cation salt mixture, and obtaining the empty pre-extractant for recycling.
The mass concentration of the dilute phosphoric acid is 20-30%, and the mass concentration of the oxalic acid is 5-10%.
The empty solvent is recycled as the pre-extractant after being supplemented with fresh extractant, and the empty solvent accounts for 1-100% of the pre-extractant in volume fraction; in the preferred scheme, the back extraction liquid accounts for 5-95% of the volume of the pre-extractant; in the preferred scheme, the back extraction liquid accounts for 10-90% of the volume of the pre-extractant; it is further preferred that the empty solvent comprises 60-100% by volume of the pre-extractant; in the preferred scheme, the back extraction liquid accounts for 70-90% of the volume of the pre-extractant; in the preferred scheme, the back extraction liquid accounts for 80-90% of the volume of the pre-extractant;
the phosphate mixture formed in the heavy phase after back extraction is used as fertilizer additive or separated and purified to obtain metal cation salt.
The invention, the mass fraction of the phosphoric acid with the removed cations in the step (2) is 53-55%, and the phosphoric acid is countercurrent contacted and extracted with a purifying extractant;
the mass concentration of the phosphoric acid is 53-55%, and the mass concentration of the concentrated phosphoric acid is P 2 O 5 And (5) counting.
The purifying extractant is one or more of phenyl phosphate, citrate, ketone and alcohol solvents.
The phenyl phosphate solvent comprises any one of triphenyl phosphate, tricresyl phosphate, diphenyl monooctyl phosphate, tert-butylphenyl diphenyl phosphate, bis (4-nitrobenzene) phosphate, 3, 5-bis (isopropyl) phenyl diphenyl 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 purifying extractant, and under the condition of the purifying extractant, the compound containing the anionic impurities in the phosphoric acid is rapidly and highly selectively separated under the condition of the concentration of the phosphoric acid and the condition of the purifying extractant, so that the compound containing the anionic impurities is removed. The high selectivity means that under the conditions of the phosphoric acid concentration and the extractant, the selectivity to the purified extractant is 80% -95%, and further, the selectivity to the purified extractant is 85% -95%. The rapid selectivity means 1-500s, further rapid selectivity means 1-350s, further rapid selectivity means 1-100s, further rapid selectivity means 1-120s. 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 addition, the purifying extractant and the extracting 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 extracting process is reduced, and the loss of phosphoric acid in a light phase in the extracting 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.
The extractant of the application does not affect the physicochemical properties of phosphoric acid and does not cause pollution to phosphoric acid environment, and in the extractant environment with excessive mass relative to phosphoric acid, most anions in phosphoric acid are retained in the phosphoric acid environment, and phosphoric acid molecules are rapidly and highly selectively dissolved in the solvent of the application.
The purifying extractant is phenyl phosphate solvent and ketone solvent in the volume ratio of 1:0.1-50, further in a volume ratio of 1:1-40, further in a volume ratio of 1: 1-30;
the extractant is phenyl phosphate solvent and alcohol solvent in the volume ratio of 1:0.1-50, further in a volume ratio of 1:1-40, further in a volume ratio of 1: 1-30;
The extractant is citrate ester solvent and ketone solvent in the volume ratio of 1:0.1-50, further in a volume ratio of 1:1-40, further in a volume ratio of 1: 1-30;
the extractant is citric acid ester solvent and alcohol solvent in the volume ratio of 1:0.1-50, further in a volume ratio of 1:1-40, further in a volume ratio of 1: 1-30.
The volume ratio of the phenyl phosphate solvent to the ketone solvent or the alcohol solvent in the extracting agent in the mixture means that the high-efficiency extraction can be realized under the condition that the concentration range of the phenyl phosphate extracting agent relative to the ketone extracting agent or the alcohol solvent is wide. The ketone extractant or the alcohol solvent is used as the solvent and the active ingredient of the extractant, and mainly plays a role in dispersing the extractant, and further realizes the dispersion of the solvent in the phosphoric acid environment, thereby realizing the efficient extraction of phosphoric acid.
The volume ratio of the citric acid ester solvent to the ketone solvent or the alcohol solvent is that the high-efficiency extraction can be realized under the condition that the concentration range of the phenyl phosphate extractant relative to the ketone extractant or the alcohol solvent is equal. The ketone extractant or the alcohol solvent is used as the solvent and the active ingredient of the extractant, and mainly plays a role in dispersing the extractant, and further realizes the dispersion of the solvent in the phosphoric acid environment, thereby realizing the efficient extraction of phosphoric acid.
In the process of forming the mixture, mixing the mixture at a rotating speed of 400-1000r/min for 1-180 min;
further preferably, mixing is carried out for 1-120min at a rotation speed of 500-1000r/min after mixing;
it is further preferable that the mixing is carried out at a rotational speed of 500r/min, 600r/min, 700r/min, 900r/min for 1 to 60min after the mixing.
The extractant is any one of bis (2-isopropylphenyl) phenyl phosphate, methyl isobutyl ketone, cyclohexanone, methyl ethyl ketone, 3-pentanone and 2-hexanone, and is mixed at high speed for 1-60min at the rotating speed of 500r/min, 600r/min, 700r/min and 900r/min, preferably 1min, 3min, 5min, 10min, 20min, 30min, 40min, 50min or 60min.
The extractant is any one of tert-butylphenyl diphenyl phosphate, methyl isobutyl ketone, cyclohexanone, methyl ethyl ketone, 3-pentanone and 2-hexanone, and is mixed at high speed for 1-60min at the rotating speed of 500r/min, 600r/min, 700r/min and 900r/min, and the preferable scheme is 1min, 3min, 5min, 10min, 20min, 30min, 40min, 50min or 60min.
The extractant is diphenyl monooctyl phosphate and any one of methyl isobutyl ketone, cyclohexanone, methyl ethyl ketone, 3-pentanone and 2-hexanone, and is mixed at high speed for 1-60min at the rotating speed of 500r/min, 600r/min, 700r/min and 900r/min, and the preferable scheme is 1min, 3min, 5min, 10min, 20min, 30min, 40min, 50min or 60min.
The extractant is selected from tricresyl phosphate, methyl isobutyl ketone, cyclohexanone, methyl ethyl ketone, 3-pentanone and 2-hexanone, and is mixed at high speed for 1-60min at rotation speed of 500r/min, 600r/min, 700r/min and 900r/min, preferably 1min, 3min, 5min, 10min, 20min, 30min, 40min, 50min or 60min.
The extractant is any one of triphenyl phosphate, methyl isobutyl ketone, cyclohexanone, methyl ethyl ketone, 3-pentanone and 2-hexanone, and is mixed at high speed for 1-60min at the rotating speed of 500r/min, 600r/min, 700r/min and 900r/min, and the preferable scheme is 1min, 3min, 5min, 10min, 20min, 30min, 40min, 50min or 60min.
The extractant is any one of bis (2, 6-dimethylphenyl) phosphate, methyl isobutyl ketone, cyclohexanone, methyl ethyl ketone, 3-pentanone and 2-hexanone and is mixed at high speed for 1-60min at the rotating speed of 500r/min, 600r/min, 700r/min and 900r/min, and the preferable scheme is 1min, 3min, 5min, 10min, 20min, 30min, 40min, 50min or 60min.
The extractant is any one of bis (4-nitrobenzene) phosphate, methyl isobutyl ketone, cyclohexanone, methyl ethyl ketone, 3-pentanone and 2-hexanone, and is mixed at high speed for 1-60min at the rotating speed of 500r/min, 600r/min, 700r/min and 900r/min, preferably 1min, 3min, 5min, 10min, 20min, 30min, 40min, 50min or 60min.
The extractant is 3, 5-bis (isopropyl) phenyl diphenyl phosphate and any one of methyl isobutyl ketone, cyclohexanone, methyl ethyl ketone, 3-pentanone and 2-hexanone, and the extractant is mixed at high speed for 1-60min at the rotating speed of 500r/min, 600r/min, 700r/min and 900r/min, and the preferential scheme is 1min, 3min, 5min, 10min, 20min, 30min, 40min, 50min or 60min.
The extractant is (2-isopropylphenyl) phenyl phosphate and any one of tert-butanol, isoamyl alcohol, isobutanol, n-butanol, n-hexanol, n-octanol and tetradecanol, and the high-speed mixing is carried out for 1-60min at the rotating speed of 500r/min, 600r/min, 700r/min and 900r/min, preferably 1min, 3min, 5min, 10min, 20min, 30min, 40min, 50min or 60min.
The extractant is tert-butyl phenyl diphenyl phosphate and any one of tert-butanol, isoamyl alcohol, isobutanol, n-butanol, n-hexanol, n-octanol and tetradecanol, and is mixed at high speed for 1-60min at the rotation speed of 500r/min, 600r/min, 700r/min and 900r/min, preferably 1min, 3min, 5min, 10min, 20min, 30min, 40min, 50min or 60min.
The extractant is diphenyl monooctyl phosphate and any one of tert-butanol, isoamyl alcohol, isobutanol, n-butanol, n-hexanol, n-octanol and tetradecanol, and is mixed at high speed for 1-60min at the rotating speed of 500r/min, 600r/min, 700r/min and 900r/min, preferably 1min, 3min, 5min, 10min, 20min, 30min, 40min, 50min or 60min.
The extractant is tricresyl phosphate and any one of tert-butanol, isoamyl alcohol, isobutanol, n-butanol, n-hexanol, n-octanol and tetradecanol, and is mixed at high speed for 1-60min at the rotation speed of 500r/min, 600r/min, 700r/min and 900r/min, preferably 1min, 3min, 5min, 10min, 20min, 30min, 40min, 50min or 60min.
The extractant is triphenyl phosphate and any one of tertiary butanol, isoamyl alcohol, isobutyl alcohol, n-butyl alcohol, n-hexyl alcohol, n-octyl alcohol and tetradecyl alcohol, and is mixed at high speed for 1-60min at the rotating speed of 500r/min, 600r/min, 700r/min and 900r/min, preferably 1min, 3min, 5min, 10min, 20min, 30min, 40min, 50min or 60min.
The extractant is any one of di (4-nitrobenzene) phosphate and tert-butanol, isoamyl alcohol, isobutanol, n-butanol, n-hexanol, n-octanol and tetradecanol, and is mixed at high speed for 1-60min at the rotation speed of 500r/min, 600r/min, 700r/min and 900r/min, preferably 1min, 3min, 5min, 10min, 20min, 30min, 40min, 50min or 60min.
The extractant is 3, 5-bis (isopropyl) phenyl diphenyl phosphate and any one of tertiary butanol, isoamyl alcohol, isobutyl alcohol, n-butyl alcohol, n-hexyl alcohol, n-octyl alcohol and tetradecyl alcohol, and the high-speed mixing is carried out for 1-60min at the rotating speed of 500r/min, 600r/min, 700r/min and 900r/min, and the preferable scheme is 1min, 3min, 5min, 10min, 20min, 30min, 40min, 50min or 60min.
The extractant is prepared by mixing bis (2, 6-dimethylphenyl) phosphate with any one of tert-butanol, isoamyl alcohol, isobutanol, n-butanol, n-hexanol, n-octanol and tetradecanol at high speed for 1-60min at a rotation speed of 500r/min, 600r/min, 700r/min and 900r/min, preferably 1min, 3min, 5min, 10min, 20min, 30min, 40min, 50min or 60min.
The extractant is any one of tri-n-butyl citrate, methyl isobutyl ketone, cyclohexanone, methyl ethyl ketone, 3-pentanone and 2-hexanone, and is mixed at high speed for 1-60min at the rotating speed of 500r/min, 600r/min, 700r/min and 900r/min, preferably 1min, 3min, 5min, 10min, 20min, 30min, 40min, 50min or 60min.
The extractant is any one of acetyl tributyl citrate, methyl isobutyl ketone, cyclohexanone, methyl ethyl ketone, 3-pentanone and 2-hexanone, and is mixed at high speed for 1-60min at the rotating speed of 500r/min, 600r/min, 700r/min and 900r/min, preferably 1min, 3min, 5min, 10min, 20min, 30min, 40min, 50min or 60min.
The extractant is any one of citric acid hard ester, methyl isobutyl ketone, cyclohexanone, methyl ethyl ketone, 3-pentanone and 2-hexanone, and is mixed at high speed for 1-60min at a rotation speed of 500r/min, 600r/min, 700r/min and 900r/min, preferably 1min, 3min, 5min, 10min, 20min, 30min, 40min, 50min or 60min.
The extractant is acetyl tri-hexyl citrate and any one of methyl isobutyl ketone, cyclohexanone, methyl ethyl ketone, 3-pentanone and 2-hexanone, and is mixed at high speed for 1-60min at the rotating speed of 500r/min, 600r/min, 700r/min and 900r/min, preferably 1min, 3min, 5min, 10min, 20min, 30min, 40min, 50min or 60min.
The extractant is isopropyl citrate and methyl isobutyl ketone, cyclohexanone, methyl ethyl ketone, 3-pentanone and 2-hexanone, and is mixed at high speed for 1-60min at rotation speed of 500r/min, 600r/min, 700r/min and 900r/min, preferably 1min, 3min, 5min, 10min, 20min, 30min, 40min, 50min or 60min.
The extractant is any one of butyryl-trihexyl citrate, methyl isobutyl ketone, cyclohexanone, methyl ethyl ketone, 3-pentanone and 2-hexanone, and is mixed at high speed for 1-60min at a rotation speed of 500r/min, 600r/min, 700r/min and 900r/min, preferably 1min, 3min, 5min, 10min, 20min, 30min, 40min, 50min or 60min.
The extractant is tributyl citrate and any one of tert-butyl alcohol, isoamyl alcohol, isobutyl alcohol, n-butyl alcohol, n-hexyl alcohol, n-octyl alcohol and tetradecyl alcohol, and is mixed at high speed for 1-60min at the rotating speed of 500r/min, 600r/min, 700r/min and 900r/min, preferably 1min, 3min, 5min, 10min, 20min, 30min, 40min, 50min or 60min.
The extractant is acetyl tributyl citrate and any one of tert-butyl alcohol, isoamyl alcohol, isobutyl alcohol, n-butyl alcohol, n-hexyl alcohol, n-octyl alcohol and tetradecyl alcohol, and the extractant is mixed at high speed for 1-60min at the rotating speed of 500r/min, 600r/min, 700r/min and 900r/min, and the preferable scheme is 1min, 3min, 5min, 10min, 20min, 30min, 40min, 50min or 60min.
The extractant is any one of citric acid hard ester, tert-butanol, isoamyl alcohol, isobutanol, n-butanol, n-hexanol, n-octanol and tetradecanol, and is mixed at high speed for 1-60min at a rotation speed of 500r/min, 600r/min, 700r/min and 900r/min, preferably 1min, 3min, 5min, 10min, 20min, 30min, 40min, 50min or 60min.
The extractant is acetyl tri-hexyl citrate and any one of tert-butanol, isoamyl alcohol, isobutanol, n-butanol, n-hexanol, n-octanol and tetradecanol, and is mixed at high speed for 1-60min at the rotation speed of 500r/min, 600r/min, 700r/min and 900r/min, preferably 1min, 3min, 5min, 10min, 20min, 30min, 40min, 50min or 60min.
The extractant is isopropyl citrate and any one of tert-butanol, isoamyl alcohol, isobutanol, n-butanol, n-hexanol, n-octanol and tetradecanol, and is mixed at high speed for 1-60min at a rotation speed of 500r/min, 600r/min, 700r/min and 900r/min, preferably 1min, 3min, 5min, 10min, 20min, 30min, 40min, 50min or 60min.
The extractant is butyryl-trihexyl citrate, tert-butanol, isoamyl alcohol, isobutanol, n-butanol, n-hexanol, n-octanol and tetradecanol, and is mixed at high speed for 1-60min at a rotation speed of 500r/min, 600r/min, 700r/min and 900r/min, preferably 1min, 3min, 5min, 10min, 20min, 30min, 40min, 50min or 60min.
The extraction reaction temperature of the concentrated phosphoric acid and/or the purified extractant in the countercurrent contact extraction process is 20-60 ℃, the pressure is 0.01-0.6 MPa, and the extraction time is 1-30min;
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 30-55 ℃, the pressure is 0.01-0.5MPa, and the extraction time is 1-25min;
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 1-20min.
The technical condition of mixed extraction is adopted in the process of mixing the combined extracting agents, which is one of key technical characteristics for realizing extraction efficiency. The inventor finds that the mixed liquid formed by the combined extractant after the mixed extractant is stirred in the process of testing is in a mutually embedded mixed state. The color of the mixture is basically turbid or oil emulsion under the condition of stirring at a low speed of 400r/min or below, and the formed mixture is relatively dispersed more uniformly after the mixture is mixed at 500r/min or above. 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 addition amount of the extractant is 1-5 times of the volume of the concentrated phosphoric acid. More preferably, the extractant of the present application is added in an amount of 1 to 3 times the volume of the concentrated phosphoric acid in the countercurrent contact extraction process. It is further preferred that the extractant according to the application is added in an amount of 1-2 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 concentrated phosphoric acid and the extractant are subjected to countercurrent contact extraction from top to bottom and from bottom to top, 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 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.
Desulfurizing the light phase obtained after the extraction is completed, and back-extracting the light phase after the desulfurization is completed; mixing the heavy phase obtained after extraction and the heavy phase obtained after desulfurization, resolving to obtain raffinate acid, mixing and filtering the raffinate acid and the settled silt acid to obtain filtered clear liquid, and pre-extracting the filtered clear liquid to obtain phosphorus-containing filter residues which are used as fertilizer production;
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 20-35%, 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.
adding water into the light phase after desulfurization is completed to carry out back extraction to obtain heavy phase back extraction acid and a 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 no-load solvent purifying extractant is 1-100%, preferably the volume fraction of the no-load solvent in the purifying extractant is 5-95%, and more preferably the volume fraction of the back-extraction liquid in the purifying extractant is 10-90%. In some cases, to achieve efficient use of the solvent, the volume fraction of the light phase empty solvent clean extractant is 80-99%, preferably the empty solvent is 80-90%, and more preferably the empty solvent is 70-90%.
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, the application supplements part of fresh extractant in the circulating process of the no-load solvent, wherein the formula ratio of the fresh extractant to the extractant in the raw materials is as follows1-30% (volume fraction), and preferably 10-30% volume fraction of solvent is simultaneously used for synchronous regeneration to remove impurities. Such as SO in the phosphoric acid index obtained by extraction 4 2- When the ion content exceeds 10ppm, SO is more preferable 4 2- When the ion content exceeds 5ppm, fresh extractant is added during the circulation of the empty solvent.
The heavy phase extraction acid is treated by vacuum distillation to remove solvent and then is decolorized by active carbon, wherein the vacuum distillation condition is that the solvent is removed under 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 (3) is 30-35 ℃, and the cooling and slurrying process is carried out under the condition of stirring at 10-50 r/min.
In the step (3), the pulpified phosphoric acid is cooled to 25-30 ℃ and then is introduced into a suspension crystallizer, the suspension crystallization process adopts gradient cooling to 10-20 ℃, the stirring speed in the suspension crystallization process is 10-50r/min, the gradient cooling stages are multiple stages, such as 2-6 stages, and in some embodiments, a gradient cooling mode of 2-4 stages is adopted to realize suspension crystallization, and the suspension crystallization 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.
And (3) recycling the mother liquor obtained after filtering in the step (3) into clear liquor for pre-extraction.
The invention also provides a phosphoric acid, which is obtained by adopting the purification process, wherein the cationic Fe 2 O 3 、MgO、Al 2 O 3 The content is less than 3ppm, more preferably less than 2ppm, more preferably less than 1ppm, more preferably less than 0.5ppm, more preferably less than 0.1ppm;
said phosphate anion content anions SO 4 2- ＜5ppm、F - ＜5ppm、Cl - Less than 5ppm; further preferably SO 4 2- ＜3ppm、F - ＜3ppm、Cl - Less than 3ppm; further preferably SO 4 2- ＜1ppm、F - ＜1ppm、Cl - ＜1ppm；
The mass concentration is 85% or more, P is 2 O 5 And (5) counting.
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 1, and the specific steps are as follows:
preparation of the pre-extractant: adding 4-chlorophenyl dichlorophosphate into isoamyl alcohol to prepare a mixed solution with the mass concentration of 8.5wt%, and carrying out mixed extraction on the mixed solution for 3min at the rotating speed of 500r/min to obtain an extraction solvent.
Configuration of purifying extractant: diphenyl monooctyl phosphate and isoamyl alcohol in a volume ratio of 1:25, and mixing at 600r/min for 3min.
Desulfurizing agent: the mass concentration of the dilute phosphoric acid solution of the barium carbonate is 35%, and the mass fraction of the barium carbonate in the dilute phosphoric acid solution of the barium carbonate is 30%.
1. Pre-purification procedure:
(1) Step 1, pre-sedimentation: and (3) conveying the crude phosphoric acid with the number of 1 into a settling tank, settling for 1h by adding a settling agent (polyacrylamide) to obtain clear acid, overflowing the clear acid into a clear liquid tank, performing filter pressing solid-liquid separation on the lower silt acid, conveying the solid to a fertilizer workshop to produce fertilizer, and returning clear liquid to the clear liquid tank.
(2) Step 2, pre-extraction: the temperature in the extraction tower is 45+/-5 ℃, the pressure in the extraction tower is 0.5-0.6MPa, the clear liquid obtained in the step 1 and the pre-extractant are respectively preheated to 45+/-5 ℃, then respectively enter the extraction tower from the upper part and the lower part of the extraction tower together for countercurrent contact extraction, wet phosphoric acid and the extraction solvent are respectively emulsified and dispersed into 200 mu m granularity by a turntable tower in the contact extraction process, the volume ratio of the wet phosphoric acid to the extraction solvent is 1:3.0, the contact extraction time is 5min, and the light phase 1 and the heavy phase 1 are collected after the extraction reaction is completed.
(3) Step 3, desolventizing: and (3) adding water into the light phase 1 obtained in the step (2) to carry out back extraction to obtain a phosphate mixture and a back extraction liquid. Adding 30% of dilute sulfuric acid into the back extraction liquid to remove cations such as calcium, magnesium and aluminum, adding 10% of oxalic acid to remove impurity cationic iron to obtain an empty pre-extraction agent, and adding 10% of fresh pre-extraction agent into the obtained pre-extraction agent to be used for continuous pre-extraction; the separated cation salt is used for producing fertilizer additives.
(4) Step 4, desolventizing: concentrating the heavy phase 1 obtained in the step 2 to obtain 52-55% concentrated phosphoric acid.
2. Intermediate purification process:
(1) Step 1, extraction: the temperature in the purifying extraction tower is 45+/-5 ℃, the pressure in the purifying extraction tower is 0.01-0.05MPa, and the 52-55% concentrated phosphoric acid and the purifying extractant obtained in the step 4 of the pre-purifying procedure are respectively preheated to 45+/-5 ℃, and the volume ratio of the 52-55% concentrated phosphoric acid to the purifying extractant is 1:3.5 respectively feeding the phosphoric acid and the extraction solvent into the extraction tower from the upper part and the lower part of the extraction tower together for contact extraction, respectively emulsifying and dispersing the phosphoric acid and the extraction solvent into 200 mu m granularity by a turntable tower in the contact extraction process, and collecting the light phase 2 and the heavy phase 2 containing phosphorus pentoxide after carrying out contact reaction for 5 min.
(2) And 2, fine desulfurization: and (3) carrying out reaction fine desulfurization on the light phase 2 obtained in the step 1 of the intermediate purification process by using a desulfurizing agent, wherein the volume ratio of the light phase 2 to the desulfurizing agent is 10:1, washing to obtain a light phase 3 and a heavy phase 3.
(3) Step 3, back extraction: and (3) carrying out back extraction on the light phase 3 obtained in the step (2) of the intermediate purification process by using desalted water to obtain a light phase 4 and a heavy phase 4. The light phase 4 is supplemented with 5 percent of purifying extractant with volume fraction, the purified extractant returns to the purifying extraction procedure for cyclic reaction, and the heavy phase 4 is stripping acid with mass concentration of 40-42 percent obtained after intermediate purification.
(4) And 4, raffinate acid analysis: and (3) mixing the heavy phase 2 obtained in the step (1) of the intermediate purification process with the heavy phase 3 obtained in the step (2), removing the solvent contained in the mixture by analysis to obtain raffinate, filtering the raffinate to obtain clear liquid, and returning the clear liquid 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 vacuum rectification and desolventizing on the stripping acid with the mass concentration of 40-42% obtained in the step (3) in the intermediate purification process at the absolute pressure 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 intermediate purification step 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 intermediate 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%.
3. Post-purification procedure:
(1) Step 1, suspension crystallization: cooling the concentrated phosphoric acid with 61-65% phosphorus pentoxide content obtained in the step 7 of the intermediate 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 1.0 ℃/min, and the temperature is kept for 10min; then cooling to 10+/-0.5 ℃ at 1.0 ℃/min, and preserving heat for 10min; then cooling to 3+/-0.5 ℃ at 0.5 ℃/min, and preserving heat for 10min.
(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 phosphoric acid with the mass fraction of 10-15%, and obtaining the high-purity phosphoric acid crystals with the content of 98-99% through centrifugal filtration.
(3) Step 3, dilution: the high purity phosphoric acid crystals with 98-99% content obtained in the post-purification step 2 were diluted with desalted water to obtain phosphoric acid with about 85%, and the phosphoric acid yield and properties are shown in table 1.
(4) Step 4, mother liquor treatment: and (3) returning the mother liquor obtained in the step (1) of the post-purification step to a pre-extraction clear liquid tank for a pre-extraction step.
Example 2
The wet phosphoric acid purification process is carried out by adopting the process and the crude phosphoric acid with the number of 2, and the specific steps are as follows:
preparation of the pre-extractant: tris (2, 2-trifluoroethyl) phosphite was added to cyclohexanol to prepare a mixed solution having a mass concentration of 16wt%, and the mixed solution was mixed at a rotation speed of 600r/min for 5 minutes to obtain an extraction solvent.
Configuration of purifying extractant: acetyl tributyl citrate and cyclohexanone in a volume ratio of 1:30, and mixing at 600r/min for 10min to form a transparent suspension.
Desulfurizing agent: the mass concentration of the dilute phosphoric acid solution of the barium carbonate is 35%, and the mass fraction of the barium carbonate in the dilute phosphoric acid solution of the barium carbonate is 30%.
1. Pre-purification procedure:
(1) Step 1, pre-sedimentation: and the number 2 is that the crude phosphoric acid is sent to a settling tank, the clear acid is obtained by adding a precipitator polyacrylamide for settling for 2 hours, the clear acid overflows to a clear liquid tank, the lower part of the clear acid is subjected to filter pressing and solid-liquid separation, the solid is sent to a fertilizer workshop for producing fertilizer, and the clear liquid is returned to the clear liquid tank.
(2) Step 2, pre-extraction: the temperature in the extraction tower is 45+/-2 ℃, the pressure in the extraction tower is 0.5-0.6MPa, the clear liquid obtained in the step 1 and the pre-extractant are respectively preheated to 45+/-2 ℃, then respectively enter the extraction tower from the upper part and the lower part of the extraction tower together for countercurrent contact extraction, wet phosphoric acid and the extraction solvent are respectively emulsified and dispersed into 300 mu m granularity by a turntable tower in the contact extraction process, the mass ratio of the wet phosphoric acid to the extraction solvent is 1:1.2, the contact extraction time is 3min, and the light phase 1 and the heavy phase 1 are collected after the extraction reaction is completed.
(3) Step 3, desolventizing: adding 30% of dilute sulfuric acid with the mass fraction of 30% into the light phase 1 obtained in the step 2 to remove cations such as calcium, magnesium and aluminum, adding 10% of oxalic acid to remove impurity cationic iron to obtain an empty pre-extractant, and adding 10% of fresh pre-extractant into the obtained pre-extractant for continuous pre-extraction; the separated cation salt is used for producing fertilizer additives.
(4) Step 4, desolventizing: concentrating the heavy phase 1 obtained in the step 2 to obtain 52-55% concentrated phosphoric acid.
2. Intermediate purification process:
(1) Step 1, extraction: the temperature in the purifying extraction tower is 45+/-5 ℃, the pressure in the purifying extraction tower is 0.01-0.05MPa, and the 52-55% concentrated phosphoric acid and the purifying extractant obtained in the step 4 of the pre-purifying procedure are respectively preheated to 45+/-5 ℃, and the volume ratio of the 52-55% concentrated phosphoric acid to the purifying extractant is 1:2.8 respectively feeding the phosphoric acid and the extraction solvent into the extraction tower from the upper part and the lower part of the extraction tower together for contact extraction, respectively emulsifying and dispersing the phosphoric acid and the extraction solvent into 300 mu m granularity by a turntable tower in the contact extraction process, and collecting the light phase 2 and the heavy phase 2 containing phosphorus pentoxide after carrying out contact reaction for 8 min.
(2) And 2, fine desulfurization: and (3) carrying out reaction fine desulfurization on the light phase 2 obtained in the step 1 of the intermediate purification process by using a desulfurizing agent, wherein the volume ratio of the light phase 2 to the desulfurizing agent is 10:1, washing to obtain a light phase 3 and a heavy phase 3.
(3) Step 3, back extraction: and (3) carrying out back extraction on the light phase 3 obtained in the step (2) of the intermediate purification process by using desalted water to obtain a light phase 4 and a heavy phase 4. The light phase 4 is supplemented with 5 percent of purifying extractant with volume fraction, the purified extractant returns to the purifying extraction procedure for cyclic reaction, and the heavy phase 4 is stripping acid with mass concentration of 40-42 percent obtained after intermediate purification.
(4) And 4, raffinate acid analysis: and (3) mixing the heavy phase 2 obtained in the step (1) of the intermediate purification process with the heavy phase 3 obtained in the step (2), removing the solvent contained in the mixture by analysis to obtain raffinate, filtering the raffinate to obtain clear liquid, and returning the clear liquid 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 vacuum rectification and desolventizing on the stripping acid with the mass concentration of 40-42% obtained in the step (3) in the intermediate purification process at the absolute pressure 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 intermediate purification step 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 intermediate 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%.
3. Post-purification procedure:
(1) Step 1, suspension crystallization: cooling the concentrated phosphoric acid with 61-65% phosphorus pentoxide content obtained in the step 7 of the intermediate 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 1.8 ℃/min, and the temperature is kept for 10min; then cooling to 10+/-0.5 ℃ at 1.2 ℃/min, and preserving heat for 10min; then cooling to 1+/-0.5 ℃ at 0.6 ℃/min, and preserving heat for 10min.
(2) Step 2, centrifugal filtration washing: washing the phosphoric acid crystals obtained in the step 1 of the post-purification process by adopting food-grade phosphoric acid with the mass fraction of 10-15%, and obtaining the high-purity phosphoric acid crystals with the content of 98-99% through centrifugal filtration.
(3) Step 3, dilution: the high purity phosphoric acid crystals with 98-99% content obtained in the post-purification step 2 were diluted with desalted water to obtain phosphoric acid with about 85%, and the phosphoric acid yield and properties are shown in table 1.
(4) Step 4, mother liquor treatment: and (3) returning the mother liquor obtained in the step (1) of the post-purification step to a pre-extraction clear liquid tank for a pre-extraction step.
Example 3
The wet phosphoric acid purification process is carried out by adopting the process and the crude phosphoric acid with the number of 2, and the specific steps are as follows:
preparation of the pre-extractant: and adding the phosphoric acid butyrate into octanol to prepare a mixed solution with the mass concentration of 25wt%, and performing overspeed mixing on the mixed solution at the rotating speed of 600r/min for 10min to obtain the extraction solvent.
Configuration of purifying extractant: butyryl-trihexyl citrate and isoamyl alcohol in a volume ratio of 1:22, and mixing at an overspeed of 800r/min for 20min to form a transparent suspension.
Desulfurizing agent: the mass concentration of the dilute phosphoric acid solution of the barium carbonate is 35%, and the mass fraction of the barium carbonate in the dilute phosphoric acid solution of the barium carbonate is 30%.
1. Pre-purification procedure:
(1) Step 1, pre-sedimentation: and (3) conveying the crude phosphoric acid with the number of 1 into a settling tank, settling for 1h by adding a settling agent (polyacrylamide) to obtain clear acid, overflowing the clear acid into a clear liquid tank, performing pressure filtration solid-liquid separation on the lower silt acid, conveying the solid to a fertilizer workshop to produce fertilizer, and returning clear liquid to the clear liquid tank.
(2) Step 2, pre-extraction: the temperature in the extraction tower is 45+/-5 ℃, the pressure in the extraction tower is 0.5-0.6MPa, the clear liquid obtained in the step 1 and the pre-extractant are respectively preheated to 45+/-5 ℃, then respectively enter the extraction tower from the upper part and the lower part of the extraction tower together for countercurrent contact extraction, wet phosphoric acid and the extraction solvent are respectively emulsified and dispersed into particles with the granularity of 350 mu m through a turntable tower in the contact extraction process, the volume ratio of the wet phosphoric acid to the extraction solvent is 1:4, the contact extraction time is 5min, and the light phase 1 and the heavy phase 1 are collected after the extraction reaction is completed.
(3) Step 3, desolventizing: adding 30% of dilute sulfuric acid with the mass fraction of 30% into the light phase 1 obtained in the step 2 to remove cations such as calcium, magnesium and aluminum, adding 10% of oxalic acid to remove impurity cationic iron to obtain an empty pre-extractant, and adding 10% of fresh pre-extractant into the obtained pre-extractant for continuous pre-extraction; the separated cation salt is used for producing fertilizer additives.
(4) Step 4, desolventizing: concentrating the heavy phase 1 obtained in the step 2 to obtain 52-55% concentrated phosphoric acid.
2. Intermediate purification process:
(1) Step 1, extraction: the temperature in the purifying extraction tower is 45+/-5 ℃, the pressure in the purifying extraction tower is 0.01-0.05MPa, and the 52-55% concentrated phosphoric acid and the purifying extractant obtained in the step 4 of the pre-purifying procedure are respectively preheated to 45+/-5 ℃, and the volume ratio of the 52-55% concentrated phosphoric acid to the purifying extractant is 1:1.4 respectively enter the extraction tower from the upper part and the lower part of the extraction tower together for contact extraction, phosphoric acid and an extraction solvent are respectively emulsified and dispersed into particles with the granularity of 350 mu m by a turntable tower in the contact extraction process, and the light phase 2 and the heavy phase 2 containing phosphorus pentoxide are collected after 8min of contact reaction.
(2) And 2, fine desulfurization: and (3) carrying out reaction fine desulfurization on the light phase 2 obtained in the step 1 of the intermediate purification process by using a desulfurizing agent, wherein the volume ratio of the light phase 2 to the desulfurizing agent is 10:1, washing to obtain a light phase 3 and a heavy phase 3.
(3) Step 3, back extraction: and (3) carrying out back extraction on the light phase 3 obtained in the step (2) of the intermediate purification process by using desalted water to obtain a light phase 4 and a heavy phase 4. The light phase 4 is supplemented with 22 percent of purifying extractant with volume fraction, the purified extractant returns to the purifying extraction procedure for cyclic reaction, and the heavy phase 4 is stripping acid with mass concentration of 40-42 percent obtained after intermediate purification.
(4) And 4, raffinate acid analysis: and (3) mixing the heavy phase 2 obtained in the step (1) of the intermediate purification process with the heavy phase 3 obtained in the step (2), removing the solvent contained in the mixture by analysis to obtain raffinate, filtering the raffinate to obtain clear liquid, and returning the clear liquid 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 vacuum rectification and desolventizing on the stripping acid with the mass concentration of 40-42% obtained in the step (3) in the intermediate purification process at the absolute pressure 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 intermediate purification step 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 intermediate 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%.
3. Post-purification procedure:
(1) Step 1, suspension crystallization: cooling the concentrated phosphoric acid with 61-65% phosphorus pentoxide content obtained in the step 7 of the intermediate 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 1.0 ℃/min, and the temperature is kept for 10min; then cooling to 8+/-0.5 ℃ at 0.5 ℃/min, and preserving heat for 10min; then cooling to 2+/-0.5 ℃ at 0.1 ℃/min, and preserving heat for 10min.
(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 phosphoric acid with the mass fraction of 10-15%, and obtaining the high-purity phosphoric acid crystals with the content of 98-99% through centrifugal filtration.
(3) Step 3, dilution: the high purity phosphoric acid crystals with 98-99% content obtained in the post-purification step 2 were diluted with desalted water to obtain 85% phosphoric acid, and the phosphoric acid yield and properties are shown in table 1.
(4) Step 4, mother liquor treatment: and (3) returning the mother liquor obtained in the step (1) of the post-purification step to a pre-extraction clear liquid tank for a pre-extraction step.
Table 1 shows the yield of phosphoric acid and the relative changes in the content of cations and anions
Note that, in the present invention, the yield of phosphoric acid obtained after extraction is calculated as (raw material acid-raffinate acid)/raw material acid, and the extraction efficiency is represented.
Claims (19)
1. The process for extracting impurities in wet phosphoric acid is characterized in that the impurities in phosphoric acid are removed by adopting pre-extraction and intermediate extraction processes, and the process is as follows:
(1) In a closed environment, contacting and extracting crude phosphoric acid with a pre-extracting agent to obtain phosphoric acid with cations removed;
(2) Further carrying out contact extraction on the phosphoric acid with the cations removed and the purifying extractant in a closed environment to obtain the phosphoric acid with anions removed.
2. The process for extracting impurities from wet process phosphoric acid 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, 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%、Fe 2 O 3 0.4-0.8%、Al 2 O 3 1.5-3.5%、NaO 0.3-0.4%、CaO 0.3-0.4%、MgO 1.5-3.5%、As 10-50ppm。
3. The process for extracting impurities in wet phosphoric acid according to claim 2, wherein the clear solution obtained by settling the crude phosphoric acid in the step (1) is pre-extracted; the pre-extracting agent in the pre-extracting process comprises any one or more of phosphate, phosphite and substituted phosphate, and the substituent comprises any one of halogen substitution, amino, carboxyl, sulfhydryl and hydroxyl.
4. A process for extracting impurities from wet-process phosphoric acid according to claim 3, wherein said pre-extractant is selected from any one of the group consisting of bis (2, 2-trifluoroethyl) phosphite, tris (2, 2-trifluoroethyl) phosphite, triisopropylphosphite, tristearylphosphite, trimethylolpropane phosphite, tris (nonylphenyl) phosphite, tris (2, 4-di-t-butylphenyl) phosphite;
or any one selected from 4-chlorophenyl dichlorophosphate, phenyl tetramethylene hexafluorophosphate, mono [2- (perfluorooctyl) ethyl ] phosphate, O-tolyl chlorophosphate, dehydrated- (O-carboxyphenyl) chlorophosphate, tetramethyl fluorourea hexafluorophosphate, tris (tribromoneopentyl) phosphate, ethyl dichlorophosphate, 3-aminopropyl monophosphate, butyrate phosphate and dodecyl phosphate diethanolamine phosphate.
5. The process for extracting impurities from wet-process phosphoric acid according to claim 3, wherein the diluent is selected from any one or more of n-butanol, isoamyl alcohol, amyl alcohol, cyclohexanol, hexanol, heptanol, octanol, and sulfonated kerosene.
6. The process for extracting impurities in wet phosphoric acid according to claim 5, wherein the pre-extractant is diluted with a diluent to obtain a mixed solution with a mass concentration of 0.1-50wt%, or preferably diluted with a diluent to obtain a mixed solution with a mass concentration of 1-40wt%, or preferably diluted with a diluent to obtain a mixed solution with a mass concentration of 3-30 wt%.
7. The process for extracting impurities in wet-process phosphoric acid according to claim 6, wherein,
the process of diluting the solvent by adopting the diluent is to add the solvent into the diluent, and then carry out miscibility for 1-60min at the rotating speed of 400-1000 r/min; it is further preferable that the rotation speed in the process of mixing is 500r/min-1000r/min, and the mixing time is 3-40min; it is further preferable that the rotation speed in the mixing process is 500r/min, 600r/min, 700r/min, 800r/min, 900r/min or 1000r/min, and the high-speed mixing time is 5-30min.
8. The process for extracting impurities from wet-process phosphoric acid according to claim 7, wherein the crude phosphoric acid is subjected to countercurrent contact extraction with at least one pre-extractant in the extraction process in step (1), wherein the mass ratio of the crude phosphoric acid to the at least one pre-extractant is 1:1-10; it is further preferred that the mass ratio of crude phosphoric acid to at least one pre-extractant is 1:1-6; it is further preferred that the mass ratio of crude phosphoric acid to at least one pre-extractant is 1:1-4.
9. The process for extracting impurities in wet-process phosphoric acid according to claim 8, wherein the extraction reaction temperature of the crude phosphoric acid and at least one solvent in the extraction process is 20-60 ℃ and the pressure is 0.1-0.6MPa;
It is further preferred that the countercurrent contact is carried out at a temperature of 20-50deg.C and a pressure of 0.1-0.6MPa for the extraction reaction of the crude phosphoric acid with at least one solvent;
it is further preferred that the countercurrent contact is carried out at a temperature of 30 to 45℃and a pressure of 0.1 to 0.6MPa for the extraction reaction of the crude phosphoric acid with at least one solvent.
10. The process for extracting impurities in wet-process phosphoric acid according to claim 9, wherein the heavy phase decationized phosphoric acid produced after the extraction is concentrated to obtain decationized phosphoric acid with a mass fraction of 53-55%; and adding a stripping agent into the light phase to separate out metal cations, and obtaining an empty pre-extraction agent for recycling.
11. The process for extracting impurities in wet-process phosphoric acid according to claim 10, wherein the back extraction liquid is recycled as a pre-extraction agent after being supplemented with a fresh extraction agent, and the back extraction liquid accounts for 1-100% of the volume fraction of the pre-extraction agent; in the preferred scheme, the back extraction liquid accounts for 5-95% of the volume of the pre-extractant; in the preferred scheme, the back extraction liquid accounts for 10-90% of the volume of the pre-extractant;
the phosphate mixture formed in the heavy phase after back extraction is used as fertilizer additive or separated and purified to obtain metal cation salt.
12. The process for extracting impurities in wet phosphoric acid according to claim 1, wherein the phosphoric acid with cations removed in the step (2) is subjected to countercurrent contact extraction with a purifying extractant;
the purifying extractant is one or more of phenyl phosphate, citrate, ketone and alcohol solvents.
13. The process for extracting impurities from wet-process phosphoric acid according to claim 11, wherein the phenyl phosphate solvent comprises any one of triphenyl phosphate, tricresyl phosphate, diphenyl monooctyl phosphate, t-butylphenyl diphenyl phosphate, or 2-ethylhexyl diphenyl phosphate;
the citric acid esters comprise 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 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.
14. The process for extracting impurities in wet-process phosphoric acid according to claim 13, wherein the purifying extractant is phenyl phosphate solvent and ketone solvent in a volume ratio of 1:0.1-50, further in a volume ratio of 1:1-40, further in a volume ratio of 1: 1-30;
the extractant is phenyl phosphate solvent and alcohol solvent in the volume ratio of 1:0.1-50, further in a volume ratio of 1:1-40, further in a volume ratio of 1: 1-30;
the extractant is citrate ester solvent and ketone solvent in the volume ratio of 1:0.1-50, further in a volume ratio of 1:1-40, further in a volume ratio of 1: 1-30;
the extractant is citric acid ester solvent and alcohol solvent in the volume ratio of 1:0.1-50, further in a volume ratio of 1:1-40, further in a volume ratio of 1: 1-30.
15. The process for extracting impurities in wet process phosphoric acid according to claim 14, wherein the mixture is mixed at a high speed for 1 to 180 minutes at a rotation speed of 400 to 1000r/min during the formation of the mixture;
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 high-speed mixed for 1-60min at the rotating speeds of 500r/min, 700r/min and 900 r/min.
16. The process for extracting impurities in wet-process phosphoric acid according to claim 15, wherein,
in the countercurrent contact extraction process, the extraction reaction temperature of the concentrated phosphoric acid and/or the purified extractant is 20-60 ℃, the pressure is 0.01-0.6 MPa, and the extraction time is 1-30min;
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 30-55 ℃, the pressure is 0.01-0.5MPa, and the extraction time is 1-25min;
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 2-20min.
17. The process for extracting impurities in wet-process phosphoric acid according to claim 16, wherein,
the light phase and the heavy phase are obtained after extraction by the purifying extractant in the step (2); the light phase is desulfurized, desalted water is back extracted, decolorized and concentrated to obtain anion-removed phosphoric acid;
Desulfurizing the light phase, and back-extracting the light phase after desulfurization; mixing the heavy phase obtained after extraction and the heavy phase obtained after desulfurization, removing the solvent by analysis to obtain raffinate acid, mixing the raffinate acid with silt acid formed after sedimentation, filtering to obtain filtered clear liquid, and returning the filtered clear liquid to a pre-extraction procedure for pre-extraction, wherein the obtained phosphorus-containing filter residue is used as fertilizer production.
18. The process for extracting impurities in wet-process phosphoric acid according to claim 17, wherein,
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.
19. the process for extracting impurities in wet-process phosphoric acid according to claim 18, wherein the light phase is back extracted by adding desalted water after desulfurization is completed to obtain heavy phase back extraction 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 no-load solvent purifying extractant is 1-100%, preferably the no-load solvent accounts for 5-95% of the volume fraction of the purifying extractant, and further preferably the back extraction liquid accounts for 10-90% of the volume fraction of the purifying extractant;
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%.
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