JP6163079B2 - Chromium (III) carbonate and method for producing the same - Google Patents
Chromium (III) carbonate and method for producing the same Download PDFInfo
- Publication number
- JP6163079B2 JP6163079B2 JP2013221602A JP2013221602A JP6163079B2 JP 6163079 B2 JP6163079 B2 JP 6163079B2 JP 2013221602 A JP2013221602 A JP 2013221602A JP 2013221602 A JP2013221602 A JP 2013221602A JP 6163079 B2 JP6163079 B2 JP 6163079B2
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- Prior art keywords
- chromium
- carbonate
- iii
- aqueous solution
- acid
- Prior art date
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- XHFVDZNDZCNTLT-UHFFFAOYSA-H chromium(3+);tricarbonate Chemical compound [Cr+3].[Cr+3].[O-]C([O-])=O.[O-]C([O-])=O.[O-]C([O-])=O XHFVDZNDZCNTLT-UHFFFAOYSA-H 0.000 title claims description 141
- 238000004519 manufacturing process Methods 0.000 title claims description 20
- 239000011651 chromium Substances 0.000 claims description 196
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 claims description 138
- 229910052804 chromium Inorganic materials 0.000 claims description 136
- 239000007864 aqueous solution Substances 0.000 claims description 131
- 239000000243 solution Substances 0.000 claims description 109
- 238000006243 chemical reaction Methods 0.000 claims description 44
- 239000002253 acid Substances 0.000 claims description 38
- BVKZGUZCCUSVTD-UHFFFAOYSA-L Carbonate Chemical compound [O-]C([O-])=O BVKZGUZCCUSVTD-UHFFFAOYSA-L 0.000 claims description 33
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 31
- 238000001035 drying Methods 0.000 claims description 29
- 150000007524 organic acids Chemical class 0.000 claims description 27
- GRWVQDDAKZFPFI-UHFFFAOYSA-H chromium(III) sulfate Chemical compound [Cr+3].[Cr+3].[O-]S([O-])(=O)=O.[O-]S([O-])(=O)=O.[O-]S([O-])(=O)=O GRWVQDDAKZFPFI-UHFFFAOYSA-H 0.000 claims description 24
- 150000007522 mineralic acids Chemical class 0.000 claims description 20
- BFGKITSFLPAWGI-UHFFFAOYSA-N chromium(3+) Chemical compound [Cr+3] BFGKITSFLPAWGI-UHFFFAOYSA-N 0.000 claims description 14
- 239000012736 aqueous medium Substances 0.000 claims description 10
- 150000007513 acids Chemical class 0.000 claims description 8
- 239000000706 filtrate Substances 0.000 claims description 8
- 238000005406 washing Methods 0.000 claims description 8
- 238000001914 filtration Methods 0.000 claims description 6
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 claims description 5
- 229910052717 sulfur Inorganic materials 0.000 claims description 5
- 239000011593 sulfur Substances 0.000 claims description 5
- 230000004580 weight loss Effects 0.000 claims 1
- 238000007747 plating Methods 0.000 description 79
- CDBYLPFSWZWCQE-UHFFFAOYSA-L Sodium Carbonate Chemical compound [Na+].[Na+].[O-]C([O-])=O CDBYLPFSWZWCQE-UHFFFAOYSA-L 0.000 description 32
- 239000002002 slurry Substances 0.000 description 20
- 239000007788 liquid Substances 0.000 description 19
- 238000000034 method Methods 0.000 description 19
- 239000000126 substance Substances 0.000 description 17
- 230000002378 acidificating effect Effects 0.000 description 16
- 229910000029 sodium carbonate Inorganic materials 0.000 description 16
- 235000017550 sodium carbonate Nutrition 0.000 description 16
- VQWFNAGFNGABOH-UHFFFAOYSA-K chromium(iii) hydroxide Chemical compound [OH-].[OH-].[OH-].[Cr+3] VQWFNAGFNGABOH-UHFFFAOYSA-K 0.000 description 13
- 239000000843 powder Substances 0.000 description 13
- KRHYYFGTRYWZRS-UHFFFAOYSA-N Fluorane Chemical compound F KRHYYFGTRYWZRS-UHFFFAOYSA-N 0.000 description 12
- 150000003839 salts Chemical class 0.000 description 12
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 10
- PHFQLYPOURZARY-UHFFFAOYSA-N chromium trinitrate Chemical compound [Cr+3].[O-][N+]([O-])=O.[O-][N+]([O-])=O.[O-][N+]([O-])=O PHFQLYPOURZARY-UHFFFAOYSA-N 0.000 description 10
- 239000000203 mixture Substances 0.000 description 10
- 229910021555 Chromium Chloride Inorganic materials 0.000 description 9
- MUBZPKHOEPUJKR-UHFFFAOYSA-N Oxalic acid Chemical compound OC(=O)C(O)=O MUBZPKHOEPUJKR-UHFFFAOYSA-N 0.000 description 9
- QSWDMMVNRMROPK-UHFFFAOYSA-K chromium(3+) trichloride Chemical compound [Cl-].[Cl-].[Cl-].[Cr+3] QSWDMMVNRMROPK-UHFFFAOYSA-K 0.000 description 9
- 229910052751 metal Inorganic materials 0.000 description 9
- 239000002184 metal Substances 0.000 description 9
- 238000002360 preparation method Methods 0.000 description 9
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 8
- 239000003513 alkali Substances 0.000 description 8
- JOPOVCBBYLSVDA-UHFFFAOYSA-N chromium(6+) Chemical compound [Cr+6] JOPOVCBBYLSVDA-UHFFFAOYSA-N 0.000 description 8
- 238000004090 dissolution Methods 0.000 description 8
- 150000002500 ions Chemical class 0.000 description 8
- 239000002245 particle Substances 0.000 description 8
- 238000003860 storage Methods 0.000 description 8
- 239000003638 chemical reducing agent Substances 0.000 description 7
- 235000005985 organic acids Nutrition 0.000 description 7
- 238000004381 surface treatment Methods 0.000 description 7
- NLXLAEXVIDQMFP-UHFFFAOYSA-N Ammonia chloride Chemical compound [NH4+].[Cl-] NLXLAEXVIDQMFP-UHFFFAOYSA-N 0.000 description 6
- NBIIXXVUZAFLBC-UHFFFAOYSA-N Phosphoric acid Chemical compound OP(O)(O)=O NBIIXXVUZAFLBC-UHFFFAOYSA-N 0.000 description 6
- KRKNYBCHXYNGOX-UHFFFAOYSA-N citric acid Chemical compound OC(=O)CC(O)(C(O)=O)CC(O)=O KRKNYBCHXYNGOX-UHFFFAOYSA-N 0.000 description 6
- -1 for example Substances 0.000 description 6
- 239000012535 impurity Substances 0.000 description 6
- 238000003756 stirring Methods 0.000 description 6
- OFOBLEOULBTSOW-UHFFFAOYSA-N Propanedioic acid Natural products OC(=O)CC(O)=O OFOBLEOULBTSOW-UHFFFAOYSA-N 0.000 description 5
- 125000001931 aliphatic group Chemical group 0.000 description 5
- 230000000052 comparative effect Effects 0.000 description 5
- 238000005259 measurement Methods 0.000 description 5
- 239000000047 product Substances 0.000 description 5
- 239000002994 raw material Substances 0.000 description 5
- BVKZGUZCCUSVTD-UHFFFAOYSA-M Bicarbonate Chemical compound OC([O-])=O BVKZGUZCCUSVTD-UHFFFAOYSA-M 0.000 description 4
- DHMQDGOQFOQNFH-UHFFFAOYSA-N Glycine Chemical compound NCC(O)=O DHMQDGOQFOQNFH-UHFFFAOYSA-N 0.000 description 4
- 150000001450 anions Chemical class 0.000 description 4
- 230000008859 change Effects 0.000 description 4
- 239000012295 chemical reaction liquid Substances 0.000 description 4
- 239000011164 primary particle Substances 0.000 description 4
- QTBSBXVTEAMEQO-UHFFFAOYSA-N Acetic acid Chemical compound CC(O)=O QTBSBXVTEAMEQO-UHFFFAOYSA-N 0.000 description 3
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 3
- VEXZGXHMUGYJMC-UHFFFAOYSA-M Chloride anion Chemical compound [Cl-] VEXZGXHMUGYJMC-UHFFFAOYSA-M 0.000 description 3
- LYCAIKOWRPUZTN-UHFFFAOYSA-N Ethylene glycol Chemical compound OCCO LYCAIKOWRPUZTN-UHFFFAOYSA-N 0.000 description 3
- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 description 3
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 description 3
- DNIAPMSPPWPWGF-UHFFFAOYSA-N Propylene glycol Chemical compound CC(O)CO DNIAPMSPPWPWGF-UHFFFAOYSA-N 0.000 description 3
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 3
- QAOWNCQODCNURD-UHFFFAOYSA-L Sulfate Chemical compound [O-]S([O-])(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-L 0.000 description 3
- 229910000147 aluminium phosphate Inorganic materials 0.000 description 3
- 235000019270 ammonium chloride Nutrition 0.000 description 3
- 230000015572 biosynthetic process Effects 0.000 description 3
- 229910052799 carbon Inorganic materials 0.000 description 3
- 150000001844 chromium Chemical class 0.000 description 3
- 150000001875 compounds Chemical class 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 125000002887 hydroxy group Chemical group [H]O* 0.000 description 3
- 230000007774 longterm Effects 0.000 description 3
- 238000002156 mixing Methods 0.000 description 3
- 230000007935 neutral effect Effects 0.000 description 3
- 229910017604 nitric acid Inorganic materials 0.000 description 3
- 125000000962 organic group Chemical group 0.000 description 3
- 235000006408 oxalic acid Nutrition 0.000 description 3
- 239000002244 precipitate Substances 0.000 description 3
- 150000003377 silicon compounds Chemical class 0.000 description 3
- 239000008399 tap water Substances 0.000 description 3
- 235000020679 tap water Nutrition 0.000 description 3
- 150000003752 zinc compounds Chemical class 0.000 description 3
- BJEPYKJPYRNKOW-REOHCLBHSA-N (S)-malic acid Chemical compound OC(=O)[C@@H](O)CC(O)=O BJEPYKJPYRNKOW-REOHCLBHSA-N 0.000 description 2
- ATRRKUHOCOJYRX-UHFFFAOYSA-N Ammonium bicarbonate Chemical compound [NH4+].OC([O-])=O ATRRKUHOCOJYRX-UHFFFAOYSA-N 0.000 description 2
- FERIUCNNQQJTOY-UHFFFAOYSA-N Butyric acid Chemical compound CCCC(O)=O FERIUCNNQQJTOY-UHFFFAOYSA-N 0.000 description 2
- RGHNJXZEOKUKBD-SQOUGZDYSA-N D-gluconic acid Chemical compound OC[C@@H](O)[C@@H](O)[C@H](O)[C@@H](O)C(O)=O RGHNJXZEOKUKBD-SQOUGZDYSA-N 0.000 description 2
- FEWJPZIEWOKRBE-JCYAYHJZSA-N Dextrotartaric acid Chemical compound OC(=O)[C@H](O)[C@@H](O)C(O)=O FEWJPZIEWOKRBE-JCYAYHJZSA-N 0.000 description 2
- VZCYOOQTPOCHFL-OWOJBTEDSA-N Fumaric acid Chemical compound OC(=O)\C=C\C(O)=O VZCYOOQTPOCHFL-OWOJBTEDSA-N 0.000 description 2
- 239000004471 Glycine Substances 0.000 description 2
- AEMRFAOFKBGASW-UHFFFAOYSA-N Glycolic acid Chemical compound OCC(O)=O AEMRFAOFKBGASW-UHFFFAOYSA-N 0.000 description 2
- OAKJQQAXSVQMHS-UHFFFAOYSA-N Hydrazine Chemical compound NN OAKJQQAXSVQMHS-UHFFFAOYSA-N 0.000 description 2
- MHAJPDPJQMAIIY-UHFFFAOYSA-N Hydrogen peroxide Chemical compound OO MHAJPDPJQMAIIY-UHFFFAOYSA-N 0.000 description 2
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 2
- UIIMBOGNXHQVGW-UHFFFAOYSA-M Sodium bicarbonate Chemical compound [Na+].OC([O-])=O UIIMBOGNXHQVGW-UHFFFAOYSA-M 0.000 description 2
- FAPWRFPIFSIZLT-UHFFFAOYSA-M Sodium chloride Chemical compound [Na+].[Cl-] FAPWRFPIFSIZLT-UHFFFAOYSA-M 0.000 description 2
- KDYFGRWQOYBRFD-UHFFFAOYSA-N Succinic acid Natural products OC(=O)CCC(O)=O KDYFGRWQOYBRFD-UHFFFAOYSA-N 0.000 description 2
- RAHZWNYVWXNFOC-UHFFFAOYSA-N Sulphur dioxide Chemical compound O=S=O RAHZWNYVWXNFOC-UHFFFAOYSA-N 0.000 description 2
- FEWJPZIEWOKRBE-UHFFFAOYSA-N Tartaric acid Natural products [H+].[H+].[O-]C(=O)C(O)C(O)C([O-])=O FEWJPZIEWOKRBE-UHFFFAOYSA-N 0.000 description 2
- XLOMVQKBTHCTTD-UHFFFAOYSA-N Zinc monoxide Chemical compound [Zn]=O XLOMVQKBTHCTTD-UHFFFAOYSA-N 0.000 description 2
- NOGBENJVEVQHKG-UHFFFAOYSA-K [Cr+3].NS([O-])(=O)=O.NS([O-])(=O)=O.NS([O-])(=O)=O Chemical compound [Cr+3].NS([O-])(=O)=O.NS([O-])(=O)=O.NS([O-])(=O)=O NOGBENJVEVQHKG-UHFFFAOYSA-K 0.000 description 2
- WNLRTRBMVRJNCN-UHFFFAOYSA-N adipic acid Chemical compound OC(=O)CCCCC(O)=O WNLRTRBMVRJNCN-UHFFFAOYSA-N 0.000 description 2
- 230000032683 aging Effects 0.000 description 2
- 150000001298 alcohols Chemical class 0.000 description 2
- BJEPYKJPYRNKOW-UHFFFAOYSA-N alpha-hydroxysuccinic acid Natural products OC(=O)C(O)CC(O)=O BJEPYKJPYRNKOW-UHFFFAOYSA-N 0.000 description 2
- 239000001099 ammonium carbonate Substances 0.000 description 2
- 150000003863 ammonium salts Chemical class 0.000 description 2
- 150000001449 anionic compounds Chemical class 0.000 description 2
- 239000002585 base Substances 0.000 description 2
- KDYFGRWQOYBRFD-NUQCWPJISA-N butanedioic acid Chemical compound O[14C](=O)CC[14C](O)=O KDYFGRWQOYBRFD-NUQCWPJISA-N 0.000 description 2
- 239000006227 byproduct Substances 0.000 description 2
- 125000004432 carbon atom Chemical group C* 0.000 description 2
- BVKZGUZCCUSVTD-UHFFFAOYSA-N carbonic acid Chemical class OC(O)=O BVKZGUZCCUSVTD-UHFFFAOYSA-N 0.000 description 2
- 125000003178 carboxy group Chemical group [H]OC(*)=O 0.000 description 2
- 229910021563 chromium fluoride Inorganic materials 0.000 description 2
- 235000015165 citric acid Nutrition 0.000 description 2
- 150000001869 cobalt compounds Chemical class 0.000 description 2
- 238000007796 conventional method Methods 0.000 description 2
- 238000001816 cooling Methods 0.000 description 2
- 230000001186 cumulative effect Effects 0.000 description 2
- SOCTUWSJJQCPFX-UHFFFAOYSA-N dichromate(2-) Chemical compound [O-][Cr](=O)(=O)O[Cr]([O-])(=O)=O SOCTUWSJJQCPFX-UHFFFAOYSA-N 0.000 description 2
- 238000009826 distribution Methods 0.000 description 2
- 239000007789 gas Substances 0.000 description 2
- 238000010438 heat treatment Methods 0.000 description 2
- 230000001771 impaired effect Effects 0.000 description 2
- 229910001412 inorganic anion Inorganic materials 0.000 description 2
- JVTAAEKCZFNVCJ-UHFFFAOYSA-N lactic acid Chemical compound CC(O)C(O)=O JVTAAEKCZFNVCJ-UHFFFAOYSA-N 0.000 description 2
- 239000001630 malic acid Substances 0.000 description 2
- 235000011090 malic acid Nutrition 0.000 description 2
- 150000002739 metals Chemical class 0.000 description 2
- BDAGIHXWWSANSR-UHFFFAOYSA-N methanoic acid Natural products OC=O BDAGIHXWWSANSR-UHFFFAOYSA-N 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000007254 oxidation reaction Methods 0.000 description 2
- BWHMMNNQKKPAPP-UHFFFAOYSA-L potassium carbonate Chemical compound [K+].[K+].[O-]C([O-])=O BWHMMNNQKKPAPP-UHFFFAOYSA-L 0.000 description 2
- 230000008569 process Effects 0.000 description 2
- BDERNNFJNOPAEC-UHFFFAOYSA-N propan-1-ol Chemical compound CCCO BDERNNFJNOPAEC-UHFFFAOYSA-N 0.000 description 2
- 238000010405 reoxidation reaction Methods 0.000 description 2
- 238000000790 scattering method Methods 0.000 description 2
- 239000007787 solid Substances 0.000 description 2
- 238000000967 suction filtration Methods 0.000 description 2
- 239000011975 tartaric acid Substances 0.000 description 2
- 235000002906 tartaric acid Nutrition 0.000 description 2
- VZCYOOQTPOCHFL-UHFFFAOYSA-N trans-butenedioic acid Natural products OC(=O)C=CC(O)=O VZCYOOQTPOCHFL-UHFFFAOYSA-N 0.000 description 2
- FTBATIJJKIIOTP-UHFFFAOYSA-K trifluorochromium Chemical compound F[Cr](F)F FTBATIJJKIIOTP-UHFFFAOYSA-K 0.000 description 2
- 239000002699 waste material Substances 0.000 description 2
- JIAARYAFYJHUJI-UHFFFAOYSA-L zinc dichloride Chemical compound [Cl-].[Cl-].[Zn+2] JIAARYAFYJHUJI-UHFFFAOYSA-L 0.000 description 2
- ONDPHDOFVYQSGI-UHFFFAOYSA-N zinc nitrate Chemical compound [Zn+2].[O-][N+]([O-])=O.[O-][N+]([O-])=O ONDPHDOFVYQSGI-UHFFFAOYSA-N 0.000 description 2
- OWEGMIWEEQEYGQ-UHFFFAOYSA-N 100676-05-9 Natural products OC1C(O)C(O)C(CO)OC1OCC1C(O)C(O)C(O)C(OC2C(OC(O)C(O)C2O)CO)O1 OWEGMIWEEQEYGQ-UHFFFAOYSA-N 0.000 description 1
- OSWFIVFLDKOXQC-UHFFFAOYSA-N 4-(3-methoxyphenyl)aniline Chemical compound COC1=CC=CC(C=2C=CC(N)=CC=2)=C1 OSWFIVFLDKOXQC-UHFFFAOYSA-N 0.000 description 1
- QGZKDVFQNNGYKY-UHFFFAOYSA-O Ammonium Chemical compound [NH4+] QGZKDVFQNNGYKY-UHFFFAOYSA-O 0.000 description 1
- 229910000013 Ammonium bicarbonate Inorganic materials 0.000 description 1
- RGHNJXZEOKUKBD-UHFFFAOYSA-N D-gluconic acid Natural products OCC(O)C(O)C(O)C(O)C(O)=O RGHNJXZEOKUKBD-UHFFFAOYSA-N 0.000 description 1
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 1
- WQZGKKKJIJFFOK-GASJEMHNSA-N Glucose Natural products OC[C@H]1OC(O)[C@H](O)[C@@H](O)[C@@H]1O WQZGKKKJIJFFOK-GASJEMHNSA-N 0.000 description 1
- 229910001209 Low-carbon steel Inorganic materials 0.000 description 1
- GUBGYTABKSRVRQ-PICCSMPSSA-N Maltose Natural products O[C@@H]1[C@@H](O)[C@H](O)[C@@H](CO)O[C@@H]1O[C@@H]1[C@@H](CO)OC(O)[C@H](O)[C@H]1O GUBGYTABKSRVRQ-PICCSMPSSA-N 0.000 description 1
- 229910002651 NO3 Inorganic materials 0.000 description 1
- 239000004111 Potassium silicate Substances 0.000 description 1
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 1
- 239000004115 Sodium Silicate Substances 0.000 description 1
- 229920002472 Starch Polymers 0.000 description 1
- ATJFFYVFTNAWJD-UHFFFAOYSA-N Tin Chemical compound [Sn] ATJFFYVFTNAWJD-UHFFFAOYSA-N 0.000 description 1
- FMRLDPWIRHBCCC-UHFFFAOYSA-L Zinc carbonate Chemical compound [Zn+2].[O-]C([O-])=O FMRLDPWIRHBCCC-UHFFFAOYSA-L 0.000 description 1
- 238000009825 accumulation Methods 0.000 description 1
- ZOIORXHNWRGPMV-UHFFFAOYSA-N acetic acid;zinc Chemical compound [Zn].CC(O)=O.CC(O)=O ZOIORXHNWRGPMV-UHFFFAOYSA-N 0.000 description 1
- 230000009471 action Effects 0.000 description 1
- 239000001361 adipic acid Substances 0.000 description 1
- 235000011037 adipic acid Nutrition 0.000 description 1
- RSYUFYQTACJFML-DZGCQCFKSA-N afzelechin Chemical compound C1([C@H]2OC3=CC(O)=CC(O)=C3C[C@@H]2O)=CC=C(O)C=C1 RSYUFYQTACJFML-DZGCQCFKSA-N 0.000 description 1
- 229910052783 alkali metal Inorganic materials 0.000 description 1
- 229910000288 alkali metal carbonate Inorganic materials 0.000 description 1
- 150000008041 alkali metal carbonates Chemical class 0.000 description 1
- 150000001447 alkali salts Chemical class 0.000 description 1
- JGDITNMASUZKPW-UHFFFAOYSA-K aluminium trichloride hexahydrate Chemical compound O.O.O.O.O.O.Cl[Al](Cl)Cl JGDITNMASUZKPW-UHFFFAOYSA-K 0.000 description 1
- 229940009861 aluminum chloride hexahydrate Drugs 0.000 description 1
- 235000012538 ammonium bicarbonate Nutrition 0.000 description 1
- 235000012501 ammonium carbonate Nutrition 0.000 description 1
- 239000011260 aqueous acid Substances 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical group [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- RAGLTCMTCZHYEJ-UHFFFAOYSA-K azanium;chromium(3+);disulfate Chemical compound [NH4+].[Cr+3].[O-]S([O-])(=O)=O.[O-]S([O-])(=O)=O RAGLTCMTCZHYEJ-UHFFFAOYSA-K 0.000 description 1
- 230000008901 benefit Effects 0.000 description 1
- WQZGKKKJIJFFOK-VFUOTHLCSA-N beta-D-glucose Chemical compound OC[C@H]1O[C@@H](O)[C@H](O)[C@@H](O)[C@@H]1O WQZGKKKJIJFFOK-VFUOTHLCSA-N 0.000 description 1
- GUBGYTABKSRVRQ-QUYVBRFLSA-N beta-maltose Chemical compound OC[C@H]1O[C@H](O[C@H]2[C@H](O)[C@@H](O)[C@H](O)O[C@@H]2CO)[C@H](O)[C@@H](O)[C@@H]1O GUBGYTABKSRVRQ-QUYVBRFLSA-N 0.000 description 1
- KGBXLFKZBHKPEV-UHFFFAOYSA-N boric acid Chemical compound OB(O)O KGBXLFKZBHKPEV-UHFFFAOYSA-N 0.000 description 1
- 239000004327 boric acid Substances 0.000 description 1
- 125000005587 carbonate group Chemical group 0.000 description 1
- 150000004649 carbonic acid derivatives Chemical class 0.000 description 1
- 239000013522 chelant Substances 0.000 description 1
- 239000013626 chemical specie Substances 0.000 description 1
- 238000005660 chlorination reaction Methods 0.000 description 1
- 229910052801 chlorine Inorganic materials 0.000 description 1
- 150000001845 chromium compounds Chemical class 0.000 description 1
- 229910001430 chromium ion Inorganic materials 0.000 description 1
- LJAOOBNHPFKCDR-UHFFFAOYSA-K chromium(3+) trichloride hexahydrate Chemical compound O.O.O.O.O.O.[Cl-].[Cl-].[Cl-].[Cr+3] LJAOOBNHPFKCDR-UHFFFAOYSA-K 0.000 description 1
- WYYQVWLEPYFFLP-UHFFFAOYSA-K chromium(3+);triacetate Chemical compound [Cr+3].CC([O-])=O.CC([O-])=O.CC([O-])=O WYYQVWLEPYFFLP-UHFFFAOYSA-K 0.000 description 1
- QOWZHEWZFLTYQP-UHFFFAOYSA-K chromium(3+);triformate Chemical compound [Cr+3].[O-]C=O.[O-]C=O.[O-]C=O QOWZHEWZFLTYQP-UHFFFAOYSA-K 0.000 description 1
- ZKJMJQVGBCLHFL-UHFFFAOYSA-K chromium(3+);triperchlorate Chemical compound [Cr+3].[O-]Cl(=O)(=O)=O.[O-]Cl(=O)(=O)=O.[O-]Cl(=O)(=O)=O ZKJMJQVGBCLHFL-UHFFFAOYSA-K 0.000 description 1
- 229910000151 chromium(III) phosphate Inorganic materials 0.000 description 1
- IKZBVTPSNGOVRJ-UHFFFAOYSA-K chromium(iii) phosphate Chemical compound [Cr+3].[O-]P([O-])([O-])=O IKZBVTPSNGOVRJ-UHFFFAOYSA-K 0.000 description 1
- YECBRSTWAYLPIM-UHFFFAOYSA-N chromium;hydrochloride Chemical compound Cl.[Cr] YECBRSTWAYLPIM-UHFFFAOYSA-N 0.000 description 1
- 229940011182 cobalt acetate Drugs 0.000 description 1
- GVPFVAHMJGGAJG-UHFFFAOYSA-L cobalt dichloride Chemical compound [Cl-].[Cl-].[Co+2] GVPFVAHMJGGAJG-UHFFFAOYSA-L 0.000 description 1
- UFMZWBIQTDUYBN-UHFFFAOYSA-N cobalt dinitrate Chemical compound [Co+2].[O-][N+]([O-])=O.[O-][N+]([O-])=O UFMZWBIQTDUYBN-UHFFFAOYSA-N 0.000 description 1
- 229910001981 cobalt nitrate Inorganic materials 0.000 description 1
- 229910000152 cobalt phosphate Inorganic materials 0.000 description 1
- 229910000361 cobalt sulfate Inorganic materials 0.000 description 1
- 229940044175 cobalt sulfate Drugs 0.000 description 1
- KTVIXTQDYHMGHF-UHFFFAOYSA-L cobalt(2+) sulfate Chemical compound [Co+2].[O-]S([O-])(=O)=O KTVIXTQDYHMGHF-UHFFFAOYSA-L 0.000 description 1
- ZBDSFTZNNQNSQM-UHFFFAOYSA-H cobalt(2+);diphosphate Chemical compound [Co+2].[Co+2].[Co+2].[O-]P([O-])([O-])=O.[O-]P([O-])([O-])=O ZBDSFTZNNQNSQM-UHFFFAOYSA-H 0.000 description 1
- QAHREYKOYSIQPH-UHFFFAOYSA-L cobalt(II) acetate Chemical compound [Co+2].CC([O-])=O.CC([O-])=O QAHREYKOYSIQPH-UHFFFAOYSA-L 0.000 description 1
- 239000008119 colloidal silica Substances 0.000 description 1
- 239000002131 composite material Substances 0.000 description 1
- 238000011109 contamination Methods 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- QDOXWKRWXJOMAK-UHFFFAOYSA-N dichromium trioxide Chemical compound O=[Cr]O[Cr]=O QDOXWKRWXJOMAK-UHFFFAOYSA-N 0.000 description 1
- 150000002016 disaccharides Chemical class 0.000 description 1
- 238000007922 dissolution test Methods 0.000 description 1
- 239000010419 fine particle Substances 0.000 description 1
- 235000019253 formic acid Nutrition 0.000 description 1
- 239000001530 fumaric acid Substances 0.000 description 1
- 235000011087 fumaric acid Nutrition 0.000 description 1
- 125000000524 functional group Chemical group 0.000 description 1
- 239000000174 gluconic acid Substances 0.000 description 1
- 235000012208 gluconic acid Nutrition 0.000 description 1
- 239000008103 glucose Substances 0.000 description 1
- 150000004676 glycans Chemical class 0.000 description 1
- 239000000017 hydrogel Substances 0.000 description 1
- 125000004435 hydrogen atom Chemical group [H]* 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-M hydroxide Chemical compound [OH-] XLYOFNOQVPJJNP-UHFFFAOYSA-M 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 239000008235 industrial water Substances 0.000 description 1
- 239000004615 ingredient Substances 0.000 description 1
- 238000005342 ion exchange Methods 0.000 description 1
- 239000004310 lactic acid Substances 0.000 description 1
- 235000014655 lactic acid Nutrition 0.000 description 1
- PAZHGORSDKKUPI-UHFFFAOYSA-N lithium metasilicate Chemical compound [Li+].[Li+].[O-][Si]([O-])=O PAZHGORSDKKUPI-UHFFFAOYSA-N 0.000 description 1
- 229910052912 lithium silicate Inorganic materials 0.000 description 1
- 239000002932 luster Substances 0.000 description 1
- VZCYOOQTPOCHFL-UPHRSURJSA-N maleic acid Chemical compound OC(=O)\C=C/C(O)=O VZCYOOQTPOCHFL-UPHRSURJSA-N 0.000 description 1
- 239000011976 maleic acid Substances 0.000 description 1
- 150000002772 monosaccharides Chemical class 0.000 description 1
- 238000006386 neutralization reaction Methods 0.000 description 1
- 229910052759 nickel Inorganic materials 0.000 description 1
- 239000005416 organic matter Substances 0.000 description 1
- 239000003960 organic solvent Substances 0.000 description 1
- 230000001590 oxidative effect Effects 0.000 description 1
- 230000036961 partial effect Effects 0.000 description 1
- 229920001282 polysaccharide Polymers 0.000 description 1
- 239000005017 polysaccharide Substances 0.000 description 1
- 229910052700 potassium Inorganic materials 0.000 description 1
- 239000011736 potassium bicarbonate Substances 0.000 description 1
- 235000015497 potassium bicarbonate Nutrition 0.000 description 1
- 229910000028 potassium bicarbonate Inorganic materials 0.000 description 1
- 229910000027 potassium carbonate Inorganic materials 0.000 description 1
- 235000011181 potassium carbonates Nutrition 0.000 description 1
- TYJJADVDDVDEDZ-UHFFFAOYSA-M potassium hydrogencarbonate Chemical compound [K+].OC([O-])=O TYJJADVDDVDEDZ-UHFFFAOYSA-M 0.000 description 1
- 229940086066 potassium hydrogencarbonate Drugs 0.000 description 1
- NNHHDJVEYQHLHG-UHFFFAOYSA-N potassium silicate Chemical compound [K+].[K+].[O-][Si]([O-])=O NNHHDJVEYQHLHG-UHFFFAOYSA-N 0.000 description 1
- 229910052913 potassium silicate Inorganic materials 0.000 description 1
- 235000019353 potassium silicate Nutrition 0.000 description 1
- 229910052708 sodium Inorganic materials 0.000 description 1
- 239000011734 sodium Substances 0.000 description 1
- 229910000030 sodium bicarbonate Inorganic materials 0.000 description 1
- 235000017557 sodium bicarbonate Nutrition 0.000 description 1
- 239000011780 sodium chloride Substances 0.000 description 1
- NTHWMYGWWRZVTN-UHFFFAOYSA-N sodium silicate Chemical compound [Na+].[Na+].[O-][Si]([O-])=O NTHWMYGWWRZVTN-UHFFFAOYSA-N 0.000 description 1
- 229910052911 sodium silicate Inorganic materials 0.000 description 1
- AKHNMLFCWUSKQB-UHFFFAOYSA-L sodium thiosulfate Chemical compound [Na+].[Na+].[O-]S([O-])(=O)=S AKHNMLFCWUSKQB-UHFFFAOYSA-L 0.000 description 1
- 235000019345 sodium thiosulphate Nutrition 0.000 description 1
- 238000010183 spectrum analysis Methods 0.000 description 1
- 239000008107 starch Substances 0.000 description 1
- 235000019698 starch Nutrition 0.000 description 1
- 230000036962 time dependent Effects 0.000 description 1
- 230000007704 transition Effects 0.000 description 1
- 239000004246 zinc acetate Substances 0.000 description 1
- 239000011667 zinc carbonate Substances 0.000 description 1
- 235000004416 zinc carbonate Nutrition 0.000 description 1
- 229910000010 zinc carbonate Inorganic materials 0.000 description 1
- 239000011592 zinc chloride Substances 0.000 description 1
- 235000005074 zinc chloride Nutrition 0.000 description 1
- 239000011787 zinc oxide Substances 0.000 description 1
- LRXTYHSAJDENHV-UHFFFAOYSA-H zinc phosphate Chemical compound [Zn+2].[Zn+2].[Zn+2].[O-]P([O-])([O-])=O.[O-]P([O-])([O-])=O LRXTYHSAJDENHV-UHFFFAOYSA-H 0.000 description 1
- 229910000165 zinc phosphate Inorganic materials 0.000 description 1
- NWONKYPBYAMBJT-UHFFFAOYSA-L zinc sulfate Chemical compound [Zn+2].[O-]S([O-])(=O)=O NWONKYPBYAMBJT-UHFFFAOYSA-L 0.000 description 1
- 229910000368 zinc sulfate Inorganic materials 0.000 description 1
- 229960001763 zinc sulfate Drugs 0.000 description 1
Landscapes
- Inorganic Compounds Of Heavy Metals (AREA)
- Chemical Treatment Of Metals (AREA)
Description
本発明は、炭酸クロム(III)及びその製造方法に関する。本発明の方法に従い製造された炭酸クロム(III)は、例えばクロムめっきや三価クロム化成処理などの金属の表面処理に有用である。 The present invention relates to chromium (III) carbonate and a method for producing the same. Chromium (III) carbonate produced according to the method of the present invention is useful for surface treatment of metals such as chromium plating and trivalent chromium chemical conversion treatment.
クロムめっきは、装飾用及び工業用として多くの産業分野で用いられている。クロムめっきは大気中で腐食せず光沢を失わないので、装飾めっきとして広く用いられている。また高い硬度と低い摩擦係数を有するので、耐摩耗性を要する機械部品等に広く用いられている。このめっきに用いられるめっき液には多量の六価のクロムが用いられている。六価のクロムは人体への影響が懸念されるので、めっき廃液の処理の際に環境中に放出されないよう非常に厳重な条件下で三価のクロムに還元しなければならない。したがって六価のクロムに代えて、三価のクロムを用いためっき液の開発が望まれている。 Chrome plating is used in many industrial fields for decorative and industrial purposes. Chrome plating is widely used as decorative plating because it does not corrode in the atmosphere and does not lose its luster. In addition, since it has a high hardness and a low coefficient of friction, it is widely used for machine parts that require wear resistance. A large amount of hexavalent chromium is used in the plating solution used for this plating. Since hexavalent chromium is concerned about the influence on the human body, it must be reduced to trivalent chromium under very severe conditions so that it is not released into the environment during the treatment of plating waste liquid. Therefore, it is desired to develop a plating solution using trivalent chromium instead of hexavalent chromium.
三価のクロムを用いためっき液として、例えば特許文献１には、装飾用めっきのめっき液として塩化クロム、硫酸クロム、スルファミン酸クロムなどの三価のクロム化合物を用いたクロムめっき液が記載されている。しかし塩化クロムや硫酸クロム等の無機塩の三価クロムをクロム源として用いた場合、クロムはめっきで消費されるのに対し、クロム塩の対アニオンである塩化物イオンや硫酸イオンはめっき液中に残存する。そして、めっき液はその液組成を一定に保つ必要性から、消費されるクロムに相当する量のクロム源を適宜追加して使用されるため、塩化物イオンや硫酸イオンがめっき液中に蓄積されていくことになる。したがって最終的には液組成を一定に保つことができなくなって全量を新規めっき液と交換し、使用済みめっき液は廃液として処理されることになる。 As a plating solution using trivalent chromium, for example, Patent Document 1 describes a chromium plating solution using a trivalent chromium compound such as chromium chloride, chromium sulfate, chromium sulfamate as a plating solution for decorative plating. ing. However, when trivalent chromium of inorganic salts such as chromium chloride and chromium sulfate is used as the chromium source, chromium is consumed by plating, whereas chloride ions and sulfate ions, which are counter-anions of chromium salts, are contained in the plating solution. Remain. Since the plating solution needs to keep the solution composition constant, an amount of chromium source corresponding to the consumed chromium is appropriately added, so that chloride ions and sulfate ions are accumulated in the plating solution. It will follow. Therefore, eventually, the liquid composition cannot be kept constant, and the entire amount is replaced with a new plating solution, and the used plating solution is treated as a waste solution.
この問題を解決する方法として、特許文献２では、塩化クロム及び塩化アンモニウムを含むめっき液を用いて三価クロムめっきを行うに際し、めっき液の一部を冷却装置に循環させ、この冷却装置で塩化アンモニウムの一部を晶析させて取り除くことにより、めっき液中の塩化アンモニウム濃度を制御しながらめっきする三価クロムめっき方法が提案されている。 As a method for solving this problem, in Patent Document 2, when performing trivalent chromium plating using a plating solution containing chromium chloride and ammonium chloride, a part of the plating solution is circulated in a cooling device, and the cooling device is used for chlorination. There has been proposed a trivalent chromium plating method in which a part of ammonium is crystallized and removed to control the concentration of ammonium chloride in the plating solution.
また三価クロム源として、対アニオンが蓄積しない化合物である水酸化クロムをその含水ゲルの状態で用いてこの問題を解決することも提案されている（特許文献３参照）。しかし水酸化クロムは一般的に水への溶解性が低く、通常のめっき液として用いられる酸性水溶液に対しても溶解性が低い。このため、めっき液の調製に、加温下で長時間の攪拌を要する。また消費されたクロムを補充する際にも、補充した水酸化クロムを溶解するのに長時間を要する。これらの理由により、その間めっき作業が中断され、めっき液の調製及びめっき作業において問題が生じていた。 In addition, it has also been proposed to solve this problem by using chromium hydroxide, which is a compound in which the counter anion does not accumulate, in the state of its hydrogel as a trivalent chromium source (see Patent Document 3). However, chromium hydroxide generally has low solubility in water, and low solubility in an acidic aqueous solution used as a normal plating solution. For this reason, preparation of a plating solution requires long-time stirring under heating. Also, when replenishing the consumed chromium, it takes a long time to dissolve the replenished chromium hydroxide. For these reasons, the plating operation was interrupted during that time, and problems occurred in the preparation of the plating solution and the plating operation.
従来の水酸化クロムの製造方法としては、例えば特許文献４ないし６に記載の方法が知られている。しかしこれらの文献には、水酸化クロムに代えて、炭酸クロム(III)を三価クロム源として用いることについて何ら言及されていない。 As a conventional method for producing chromium hydroxide, for example, methods described in Patent Documents 4 to 6 are known. However, these documents do not mention any use of chromium (III) carbonate as a trivalent chromium source in place of chromium hydroxide.
また、下記の非特許文献１には、クロム(III)塩水溶液に炭酸アルカリ又は炭酸水素アルカリ溶液を加えて炭酸クロム(III)が得られることが記載されている。同文献には、この炭酸クロム(III)は淡緑色であると記載されている。このようにして得られる炭酸クロム(III)は、同文献に記載されているとおり沈殿となってしまうので、三価クロム源として用いることはできない。 Non-Patent Document 1 below describes that chromium carbonate (III) can be obtained by adding an alkali carbonate or hydrogencarbonate alkali solution to a chromium (III) salt aqueous solution. This document describes that this chromium (III) carbonate is light green. Since the chromium (III) carbonate obtained in this manner is precipitated as described in the document, it cannot be used as a trivalent chromium source.
このような実情に鑑み、下記特許文献７では、酸性水溶液に対する溶解性が高い炭酸クロム(III)について記載されている。この文献によれば、温度２５℃でｐＨが０．２の塩酸水溶液１リットルに、Ｃｒとして１ｇ含有に相当する量を加えたときに、３０分以内に完全溶解する炭酸クロム(III)が開示されており、実施例においても塩酸の他、硫酸や硝酸といった酸を混合して使用した酸性水溶液における溶解試験を行っており、良好な結果が得られている。 In view of such a situation, Patent Document 7 below describes chromium (III) carbonate having high solubility in an acidic aqueous solution. According to this document, chromium (III) carbonate that completely dissolves within 30 minutes when an amount corresponding to 1 g of Cr is added to 1 liter of a hydrochloric acid aqueous solution having a pH of 0.2 at a temperature of 25 ° C. is disclosed. Also in the examples, dissolution tests were carried out in an acidic aqueous solution in which acids such as sulfuric acid and nitric acid were used in addition to hydrochloric acid, and good results were obtained.
しかしながら、炭酸クロム(III)の酸性水溶液に対する溶解性は、更なる改善の余地がある。
したがって本発明の目的は、従来以上に酸性水溶液に対する溶解性に優れ、三価のクロム源として有用な炭酸クロム(III)を提供することにある。
However, there is room for further improvement in the solubility of chromium (III) carbonate in an acidic aqueous solution.
Accordingly, an object of the present invention is to provide chromium (III) carbonate which is more excellent in solubility in acidic aqueous solution than ever and is useful as a trivalent chromium source.
本発明は、ＣＯ２とＣｒとのモル比（ＣＯ２／Ｃｒ）が０．６５未満であり、１１０℃で２時間乾燥したときの乾燥減量が２０質量％以上であることを特徴とする炭酸クロム(III)を提供するものである。 The present invention is characterized in that the molar ratio of CO 2 to Cr (CO 2 / Cr) is less than 0.65, and the loss on drying when dried at 110 ° C. for 2 hours is 20% by mass or more. It provides chromium (III).
また本発明は、三価のクロムを含む水溶液中のＣｒに対する炭酸塩水溶液中のＣＯ３のモル比（ＣＯ３／Ｃｒ）が０．５〜２．０であり、反応液のｐＨが６以下であり、反応液温が０℃以上５０℃未満の条件下で、炭酸塩水溶液と三価のクロムを含む水溶液とを、水性媒体へ同時に添加して炭酸クロム(III)を生成させる第一工程、
第一工程で得られた炭酸クロム(III)を濾過後、濾液の導電率が５ｍＳ／ｃｍ以下となるまで水洗してケーキを得る第二工程、及び
第二工程で得られたケーキを、１１０℃で２時間乾燥したときの乾燥減量が２０質量％以上となるように乾燥して炭酸クロム(III)を得る第三工程、
を有することを特徴とする炭酸クロム(III)の製造方法を提供するものである。
In the present invention, the molar ratio (CO 3 / Cr) of CO 3 in the carbonate aqueous solution to Cr in the aqueous solution containing trivalent chromium is 0.5 to 2.0, and the pH of the reaction solution is 6 or less. A first step of producing chromium (III) carbonate by simultaneously adding an aqueous carbonate solution and an aqueous solution containing trivalent chromium under a reaction solution temperature of 0 ° C. or higher and lower than 50 ° C. ,
After filtering the chromium (III) carbonate obtained in the first step, the second step to obtain a cake by washing with water until the conductivity of the filtrate is 5 mS / cm or less, and the cake obtained in the second step are 110 A third step of obtaining chromium carbonate (III) by drying such that the loss on drying when dried at 2 ° C. for 2 hours is 20% by mass or more;
The present invention provides a method for producing chromium (III) carbonate, characterized by comprising:
本発明によれば、酸性水溶液に対する溶解性が高く、かつ固体状態で長期間保存した後の溶解性にも優れた炭酸クロム(III)が提供される。三価のクロム源として本発明の炭酸クロム(III)を用いることで、三価クロムめっき液の調製時間を短縮することができる。また、三価のクロム源として水酸化クロムを用いた場合に生じ易い不都合である、未溶解の水酸化クロムに起因するめっき皮膜への悪影響を防ぐことができる。また、本発明の炭酸クロム(III)を用いた三価クロム含有液を、クロムめっきや三価クロム化成処理などの金属の表面処理に用いると、三価クロム源の対アニオンがめっき液等中に蓄積しないことからめっき液等の組成を一定に保つことが容易となる。まためっき液等の調製時間が大幅に短縮されるので、関連産業に及ぼす効果は大きいものである。 According to the present invention, chromium (III) carbonate having high solubility in an acidic aqueous solution and excellent in solubility after long-term storage in a solid state is provided. By using the chromium (III) carbonate of the present invention as the trivalent chromium source, the preparation time of the trivalent chromium plating solution can be shortened. Moreover, the bad influence on the plating film resulting from the undissolved chromium hydroxide, which is a disadvantage that is likely to occur when chromium hydroxide is used as the trivalent chromium source, can be prevented. Further, when the trivalent chromium-containing liquid using chromium (III) carbonate of the present invention is used for metal surface treatment such as chromium plating or trivalent chromium chemical conversion treatment, the counter anion of the trivalent chromium source is in the plating liquid or the like. Therefore, it is easy to keep the composition of the plating solution or the like constant. In addition, since the preparation time of the plating solution and the like is greatly shortened, the effect on related industries is great.
以下、本発明をその好ましい実施形態に基づき説明する。なお以下の説明では、特に断らない限りクロムというときには、三価のクロムを意味する。本発明の炭酸クロム(III)は、一般式：Ｃｒ２Ｏ３・ｍＣＯ２・ｎＨ２Ｏで表されるものである。式中、ｍは０．２５〜２の数を表す。ｎは１．５〜８の数を表す。本式は、三酸化二クロムに炭酸根及び水が付加した表現になっているが、これは便宜的なものであり、本発明の炭酸クロム(III)は、水酸化クロムの一部の水酸基が炭酸根で置換された状態になっていると、本発明者らは推測している。 Hereinafter, the present invention will be described based on preferred embodiments thereof. In the following description, unless otherwise specified, chromium refers to trivalent chromium. The chromium (III) carbonate of the present invention is represented by the general formula: Cr 2 O 3 .mCO 2 .nH 2 O. In formula, m represents the number of 0.25-2. n represents a number from 1.5 to 8. This formula is an expression in which carbonate root and water are added to dichromium trioxide, but this is for convenience, and chromium (III) carbonate of the present invention is a partial hydroxyl group of chromium hydroxide. The present inventors presume that is in a state of being substituted with carbonate radicals.
本発明の炭酸クロム(III)は、ＣＯ２とＣｒとのモル比（ＣＯ２／Ｃｒ）が０．６５未満である点に特徴の一つを有する。本発明の炭酸クロム(III)は、前記したように便宜的に一般式：Ｃｒ２Ｏ３・ｍＣＯ２・ｎＨ２Ｏで表されるものであるが、ＣＯ２とＣｒとのモル比（ＣＯ２／Ｃｒ）が０．６５未満、好ましくは０．６以下であると、酸に対する溶解性が高いことが本発明者の検討の結果判明した。これは、炭酸クロム(III)の原料由来の炭酸イオンや重炭酸イオンが、炭酸クロム(III)に過剰に配位すると、炭酸クロム(III)中の水酸基と入れ替わることに起因して、酸に対して難溶又は不溶となるからではないかと本発明者らは推測している。ＣＯ２とＣｒとのモル比（ＣＯ２／Ｃｒ）の下限値は０．１０、特に０．１５であることが好ましい。 Carbonate chromium (III) of the present invention has one feature in that the molar ratio between CO 2 and Cr (CO 2 / Cr) is less than 0.65. As described above, the chromium (III) carbonate of the present invention is represented by the general formula: Cr 2 O 3 · mCO 2 · nH 2 O for convenience, but the molar ratio of CO 2 and Cr (CO 2 / Cr) is less than 0.65, preferably not more than 0.6, the inventors have found that the acid solubility is high. This is due to the fact that when carbonate ions or bicarbonate ions derived from the raw material of chromium carbonate (III) are excessively coordinated with chromium (III) carbonate, they are replaced with hydroxyl groups in chromium (III) carbonate. The present inventors speculate that it may be hardly soluble or insoluble. The lower limit of the molar ratio of CO 2 to Cr (CO 2 / Cr) is preferably 0.10, and particularly preferably 0.15.
ＣＯ２とＣｒとのモル比（ＣＯ２／Ｃｒ）は、Ｃｒ２Ｏ３量とＣＯ２量の測定結果からＣＯ２／Ｃｒモル比として算出する。前記Ｃｒ２Ｏ３量は、試料を酸に溶解した溶液をＩＰＣ発光分光分析装置（（株）島津製作所製、ＩＣＰＳ−８１００ＣＬ）によってＣｒを測定し、得られた値をＣｒ２Ｏ３として換算する。前記ＣＯ２量は、全有機炭素（ＴＯＣ）分析装置（（株）島津製作所製、ＳＳＭ−５０００Ａ）を用い、試料を９５０℃に加熱することで、生成・遊離したＣＯ２を赤外線ガス検出装置（（株）島津製作所製、ＴＯＣ−Ｖ ＣＰＨ）にて測定することにより求められる。 The molar ratio of CO 2 to Cr (CO 2 / Cr) is calculated as the CO 2 / Cr molar ratio from the measurement results of the Cr 2 O 3 amount and the CO 2 amount. The amount of Cr 2 O 3 is obtained by measuring Cr with an IPC emission spectroscopic analyzer (ICPS-8100CL, manufactured by Shimadzu Corporation) obtained by dissolving a sample in an acid, and converting the obtained value as Cr 2 O 3 To do. The CO 2 amount is measured by using an all-organic carbon (TOC) analyzer (manufactured by Shimadzu Corporation, SSM-5000A), and heating the sample to 950 ° C. to generate CO 2 produced and liberated by an infrared gas detector. It is calculated | required by measuring with (Shimadzu Corp. make, TOC-V CPH).
本発明の炭酸クロム(III)は、ＣＯ２とＣｒとのモル比（ＣＯ２／Ｃｒ）が０．６５未満、好ましくは０．６以下であることに加え、１１０℃で２時間乾燥したときの乾燥減量が２０質量％以上であることも特徴の一つである。炭酸クロム(III)の乾燥減量が２０質量％以上であると、酸に対する炭酸クロム(III)の溶解性が向上する。その一方で、乾燥減量が２０質量％未満であると分子間に酸素基が架橋する、所謂オクソ化が進むことに起因して、炭酸クロム(III)の溶解性が悪化するものと推測される。乾燥減量の値は高ければ高いほど好ましいが、例えば５５質量％程度、特に３５質量％程度に乾燥減量の値が高ければ、満足すべき溶解性が得られる。この観点から、乾燥減量は、好ましくは２５質量％以上５５質量％以下、更に好ましくは２５質量％以上３５質量％以下である。乾燥減量は、試料を乾燥機中で１１０℃で２時間乾燥した後質量を測定し、乾燥前の質量から乾燥後の質量を差し引くことで求める。 Carbonate chromium (III) of the present invention, the molar ratio between CO 2 and Cr (CO 2 / Cr) is less than 0.65, preferably in addition to being 0.6 or less, when dried for 2 hours at 110 ° C. It is also one of the characteristics that the loss on drying is 20% by mass or more. When the loss on drying of chromium (III) carbonate is 20% by mass or more, the solubility of chromium (III) carbonate in an acid is improved. On the other hand, if the loss on drying is less than 20% by mass, it is presumed that the solubility of chromium (III) carbonate deteriorates due to the progress of so-called oxidization in which oxygen groups crosslink between molecules. . The higher the value of loss on drying, the better. However, if the value of loss on drying is, for example, about 55% by mass, especially about 35% by mass, satisfactory solubility can be obtained. In this respect, the loss on drying is preferably 25% by mass or more and 55% by mass or less, more preferably 25% by mass or more and 35% by mass or less. The loss on drying is determined by measuring the mass after drying the sample at 110 ° C. for 2 hours in a dryer and subtracting the mass after drying from the mass before drying.
本発明の炭酸クロム(III)は、純水に対しては不溶性又は難溶性であるが、酸性水溶液（例えばｐＨ２以下の酸性水溶液）に対しては溶解性が高いことも特徴である。しかも長期保存した後であっても、特に乾燥した粉末状態で保存した後であっても、その溶解性が維持される。特筆すべきは、乾燥した粉末状態で保存した後であっても、粉末状態での溶解性が高いことである。この理由は、その構造中に炭酸根を有しているからではないかと、本発明者らは推測している。これに対して従来得られていた水酸化クロムは、長期保存中に経時変化を起こし、酸又はアルカリの水溶液に対して難溶性の水酸化物に移行し易い。この原因ははっきりとはわからないが、クロムのオール化やオクソ化によって、難溶性の形態に移行するためと考えられる。このため、クロムめっき液を調製するときには、水酸化クロムが完全に溶解するまで長時間攪拌を行わなければならなかった。 The chromium (III) carbonate of the present invention is insoluble or hardly soluble in pure water, but is also characterized by high solubility in acidic aqueous solutions (for example, acidic aqueous solutions having a pH of 2 or less). Moreover, the solubility is maintained even after long-term storage, especially after storage in a dry powder state. It should be noted that the solubility in the powder state is high even after storage in the dry powder state. The present inventors speculate that this is because the structure has a carbonate group. On the other hand, conventionally obtained chromium hydroxide is subject to change over time during long-term storage, and is liable to shift to an insoluble hydroxide in an acid or alkali aqueous solution. The cause of this is not clearly understood, but is thought to be due to the transition to a sparingly soluble form due to the chromization or oxidization of chromium. For this reason, when preparing the chromium plating solution, it was necessary to stir for a long time until the chromium hydroxide was completely dissolved.
本発明の炭酸クロム(III)と、従来の製法で得られる炭酸クロム(III)とは、上述のとおり、ＣＯ２とＣｒとのモル比（ＣＯ２／Ｃｒ）や乾燥減量が相違することで区別され、それに起因して溶解特性が異なることでも区別される。すなわち、従来の炭酸クロム(III)は、温度２５℃で１．６５ｇ／Ｌのフッ化水素酸に対し、等モル（Ｆ／Ｃｒ＝３．０）となるように炭酸クロム(III)を加えても、全く溶解しないかあるいは３時間以上かけないと完全溶解しないのに対して、本発明の炭酸クロム(III)は１８０分以内に完全溶解する。したがって本発明の炭酸クロム(III)は、従来の炭酸クロム(III)と異なり、クロムめっきや三価クロム化成処理等の金属の表面処理に用いられる三価のクロム源あるいは補充液として利用できるものである。本明細書において「三価クロム化成処理」とは、三価クロム塩を主成分とする水溶液と被処理物とを接触させ、該被処理物に、化学的に三価のクロムを含む皮膜を生成させる処理を言う。 As described above, the chromium (III) carbonate of the present invention and the chromium (III) carbonate obtained by the conventional production method are different in the molar ratio (CO 2 / Cr) and loss on drying of CO 2 and Cr. They are also distinguished by their different dissolution characteristics. That is, the conventional chromium (III) carbonate was added with chromium (III) carbonate so as to be equimolar (F / Cr = 3.0) with respect to 1.65 g / L hydrofluoric acid at a temperature of 25 ° C. However, it does not dissolve at all or does not completely dissolve unless it takes 3 hours or more, whereas the chromium (III) carbonate of the present invention completely dissolves within 180 minutes. Therefore, unlike the conventional chromium (III) carbonate, the chromium (III) carbonate of the present invention can be used as a trivalent chromium source or replenisher used for metal surface treatment such as chromium plating and trivalent chromium chemical conversion treatment. It is. In this specification, “trivalent chromium chemical conversion treatment” means that an aqueous solution containing a trivalent chromium salt as a main component and an object to be treated are brought into contact with each other, and a film containing trivalent chromium is chemically formed on the object to be treated. This is the process to be generated.
本発明の炭酸クロム(III)は、前記した特徴に加えて、該炭酸クロム（III）中の硫黄（Ｓ）の含有量が好ましくは０．１質量％以上、更に好ましくは０．１質量％以上５．０質量％以下、特に好ましくは０．２質量％以上４．８質量％以下であるという特徴も有している。理由は定かでないが、硫黄の含有量がこの範囲にあることでフッ化水素酸に対する溶解特性が向上することが本発明者らの検討により明らかとなった。炭酸クロム(III)中に硫黄を含有させるためには、例えば後述する本発明の炭酸クロム(III)の製造方法において、原料となる三価のクロムを含む水溶液に、硫酸クロムを使用すればよい。炭酸クロム（III）中の硫黄の含有量は、後述する実施例に記載の方法で測定される。 In addition to the above-described characteristics, the chromium (III) carbonate of the present invention preferably has a sulfur (S) content in the chromium (III) carbonate of 0.1% by mass or more, more preferably 0.1% by mass. It is also characterized by being 5.0 mass% or less, particularly preferably 0.2 mass% or more and 4.8 mass% or less. Although the reason is not clear, it has been clarified by the present inventors that the solubility in hydrofluoric acid is improved when the sulfur content is in this range. In order to contain sulfur in chromium (III) carbonate, for example, in the method for producing chromium (III) carbonate of the present invention described later, chromium sulfate may be used in an aqueous solution containing trivalent chromium as a raw material. . The sulfur content in the chromium (III) carbonate is measured by the method described in the examples described later.
本発明の炭酸クロム(III)は、炭酸塩水溶液と三価のクロムを含む水溶液とをｐＨが好ましくは６以下、更に好ましくは４〜６、一層好ましくは５以上６未満で、０℃以上５０℃未満の温度で接触させて得られたものである。本発明の炭酸クロム(III)は、一次粒子の平均粒径Ｄが好ましくは１０００ｎｍ以下、更に好ましくは５０〜５００ｎｍという微粒のものである。また、本発明の炭酸クロム(III)は、前記一次粒子が集合した凝集体であってもよい。凝集体の場合は、粒度分布測定装置により測定された体積平均粒子径ＭＶが１００μｍ以下、特に３〜５０μｍであると、該炭酸クロム(III)を長期間保存したときの経時変化（溶解性の低下）が少なくなり、一層良好な溶解性が保てることから好ましい。炭酸クロム(III)の一次粒子径は、走査型電子顕微鏡（ＳＥＭ）像で炭酸クロム(III)の一次粒子２００個の粒子径を測定し、その平均値として表す。ＭＶは、炭酸クロム(III)を家庭用ミキサー等で水中に十分分散した後、レーザー回折散乱法式の粒度分布測定装置で測定した累積体積５０容量％における体積累積粒径のことである。 The chromium (III) carbonate of the present invention has a pH of an aqueous carbonate solution and an aqueous solution containing trivalent chromium of preferably 6 or less, more preferably 4 to 6, more preferably 5 or more and less than 6, and 0 ° C. or more and 50 It was obtained by contacting at a temperature of less than ° C. The chromium (III) carbonate of the present invention is a fine particle having an average primary particle diameter D of preferably 1000 nm or less, more preferably 50 to 500 nm. The chromium (III) carbonate of the present invention may be an aggregate in which the primary particles are aggregated. In the case of an aggregate, when the volume average particle diameter MV measured by a particle size distribution measuring device is 100 μm or less, particularly 3 to 50 μm, the time-dependent change (solubility of (Decrease) is reduced, and better solubility can be maintained. The primary particle diameter of chromium (III) carbonate is expressed as an average value obtained by measuring the particle diameters of 200 primary particles of chromium (III) carbonate with a scanning electron microscope (SEM) image. MV is a volume cumulative particle size at a cumulative volume of 50% by volume measured by a particle size distribution measuring apparatus of a laser diffraction scattering method after sufficiently dispersing chromium (III) carbonate in water using a household mixer or the like.
本発明の炭酸クロム(III)の粒子形状に特に制限はない。一般には球状であるが、その他に塊状などの形状でもあり得る。 There is no particular limitation on the particle shape of the chromium (III) carbonate of the present invention. In general, it is spherical, but may also be in the form of a lump.
本発明の炭酸クロム(III)は、一般に乾燥した粉末状態であるか、又は水に懸濁したスラリーの状態になっている。酸性水溶液に対する溶解性を高める観点からは、炭酸クロム(III)の調製直後から引き続いてスラリーの状態としておくことが好ましい。尤も、本発明の炭酸クロム(III)は、乾燥した粉末状態で長期間保存しても、溶解性の低下が少ないという点において、取り扱い性等の観点から極めて有利である。 The chromium (III) carbonate of the present invention is generally in a dry powder state or a slurry suspended in water. From the viewpoint of increasing the solubility in an acidic aqueous solution, it is preferable to keep the slurry in a slurry state immediately after the preparation of chromium (III) carbonate. However, the chromium (III) carbonate of the present invention is extremely advantageous from the viewpoint of handleability and the like in that the decrease in solubility is small even when stored for a long time in a dry powder state.
炭酸クロム(III)をスラリーの状態で保存しておく場合、スラリー中には炭酸クロム以外の成分が含まれていてもよく、あるいは含まれていなくてもよい。スラリー中に炭酸クロム(III)以外の成分が含まれている場合、該成分としてはＮａ、Ｋ、Ｃｌ、ＳＯ４、ＮＨ４等が挙げられる。該スラリーを、クロムめっきや三価クロム化成処理等の金属の表面処理に用いられる液の補充液として用いる場合には、該スラリーは不純物イオンを実質的に含まないことが好ましい。この理由は、補充に起因する不要なイオンの蓄積を防止するためである。本明細書に言う「不純物イオン」とは、Ｈ＋及びＯＨ−イオン以外のイオンを意味する。「実質的に含まない」とは、炭酸クロム(III)の調製及びそれを用いたスラリーの調製の間に、意図的に不純物イオンを添加しないことを意味し、不可避的に混入する微量の不純物イオンは許容する趣旨である。したがって、炭酸クロム(III)の調製及びそれを用いたスラリーの調製に使用する水としては、純水、イオン交換水の他、不純物イオンを実質的に含まない水道水、工業用水等を用いても差し支えない。 When chromium (III) carbonate is stored in a slurry state, components other than chromium carbonate may or may not be contained in the slurry. When a component other than chromium (III) carbonate is contained in the slurry, examples of the component include Na, K, Cl, SO 4 , and NH 4 . When the slurry is used as a replenisher for a solution used for metal surface treatment such as chromium plating or trivalent chromium conversion treatment, the slurry preferably contains substantially no impurity ions. The reason for this is to prevent unnecessary ion accumulation due to replenishment. The “impurity ion” referred to in this specification means ions other than H + and OH − ions. “Substantially free” means that impurity ions are intentionally not added during the preparation of chromium (III) carbonate and the slurry using the same, and trace amounts of impurities inevitably mixed in. Ion is tolerated. Therefore, as water used for preparation of chromium (III) carbonate and slurry using the same, pure water, ion exchange water, tap water substantially free of impurity ions, industrial water, etc. are used. There is no problem.
次に、本発明の炭酸クロム(III)の好適な製造方法について説明する。本発明の製造方法は、炭酸塩水溶液と三価のクロムを含む水溶液との同時添加に特徴の一つを有する。これらの水溶液を、水性媒体へ同時添加しつつ、炭酸塩水溶液と三価のクロムを含む水溶液との接触をｐＨ６以下に保つことにより、酸性水溶液に対する溶解性の高い炭酸クロム(III)を得ることができることを本発明者らは知見した。これに対して、従来の水酸化クロムや炭酸クロムの製造方法、例えば特許文献４及び６並びに非特許文献１に記載の製造方法では同時添加は採用しておらず、その代わりに、三価のクロムを含む水溶液に、水酸化ナトリウムや炭酸アルカリ等のアルカリを添加して水酸化クロムや炭酸クロムを生成させている。この方法で得られる水酸化クロムや炭酸クロムは、酸性水溶液に対する溶解性に劣るものである。 Next, the suitable manufacturing method of chromium carbonate (III) of this invention is demonstrated. The production method of the present invention is characterized by simultaneous addition of an aqueous carbonate solution and an aqueous solution containing trivalent chromium. By simultaneously adding these aqueous solutions to an aqueous medium and maintaining the contact between the aqueous carbonate solution and the aqueous solution containing trivalent chromium at pH 6 or less, chromium (III) carbonate having high solubility in an acidic aqueous solution is obtained. The present inventors have found that this is possible. On the other hand, the conventional methods for producing chromium hydroxide and chromium carbonate, for example, the production methods described in Patent Documents 4 and 6 and Non-Patent Document 1, do not employ simultaneous addition. An alkali such as sodium hydroxide or alkali carbonate is added to an aqueous solution containing chromium to produce chromium hydroxide or chromium carbonate. Chromium hydroxide and chromium carbonate obtained by this method have poor solubility in acidic aqueous solutions.
炭酸塩水溶液及び三価のクロムを含む水溶液は、これらを実質的に連続的に水性媒体へ添加する。実質的に連続的にとは、製造上の条件の変動等に起因して、添加が不可避的に一時的に不連続になる場合を許容する趣旨である。例えば、１０秒以下の時間で添加が一時的に行われない状態が生じることは「実質的に連続的に」に該当する。 An aqueous carbonate solution and an aqueous solution containing trivalent chromium are added to the aqueous medium substantially continuously. The term “substantially continuous” means that the case where the addition is inevitably temporarily discontinuous due to a change in manufacturing conditions or the like is allowed. For example, occurrence of a state in which addition is not temporarily performed in a time of 10 seconds or less corresponds to “substantially continuously”.
炭酸塩水溶液及び三価のクロムを含む水溶液の同時添加においては、操作開始時に、両水溶液を実質的に同時に添加する。尤も、本発明の効果を損なわない限度において、炭酸塩水溶液の添加の方が、三価のクロムを含む水溶液の添加に先んじてもよく、あるいはその反対に、三価のクロムを含む水溶液の添加の方が、炭酸塩水溶液の添加に先んじてもよい。操作終了時においても同様であり、両水溶液の添加は実質的に同時に終了させるが、本発明の効果を損なわない限度において、炭酸塩水溶液の添加終了の方が、三価のクロムを含む水溶液の添加終了に先んじてもよく、あるいはその反対に、三価のクロムを含む水溶液の添加終了の方が、炭酸塩水溶液の添加終了に先んじてもよい。 In the simultaneous addition of the aqueous carbonate solution and the aqueous solution containing trivalent chromium, both aqueous solutions are added substantially simultaneously at the start of the operation. However, as long as the effect of the present invention is not impaired, the addition of the aqueous carbonate solution may precede the addition of the aqueous solution containing trivalent chromium, or vice versa. This may precede the addition of the aqueous carbonate solution. The same is true at the end of the operation, and the addition of both aqueous solutions is terminated substantially simultaneously. To the extent that the effects of the present invention are not impaired, the addition of the aqueous carbonate solution is more complete for the aqueous solution containing trivalent chromium. The end of the addition may be preceded, or conversely, the end of the addition of the aqueous solution containing trivalent chromium may precede the end of the addition of the carbonate aqueous solution.
炭酸塩水溶液及び三価のクロムを含む水溶液は、水性媒体へ同時添加される。本発明において用いられる水性媒体は、好ましくはｐＨが中性域（ｐＨが７前後）のものである。このような水性媒体としては、例えば水（純水（ｐＨが約７）、水道水（ｐＨが７弱）等）や中性塩の水溶液を用いることができる。中性塩としては、例えば塩化ナトリウム等を用いることができる。また該水性媒体は、必要に応じ、低級アルコール等の水溶性有機溶剤を含有することもできる。これらの水性媒体のうち、クロムめっき液等の調製において不要な化学種の混入を防止し得る点から、水（純水、イオン交換水、水道水等）を用いることが好ましい。 The aqueous carbonate solution and the aqueous solution containing trivalent chromium are added simultaneously to the aqueous medium. The aqueous medium used in the present invention preferably has a neutral pH range (pH around 7). As such an aqueous medium, for example, water (pure water (pH is about 7), tap water (pH is less than 7), etc.) or an aqueous solution of a neutral salt can be used. As a neutral salt, sodium chloride etc. can be used, for example. The aqueous medium can also contain a water-soluble organic solvent such as a lower alcohol, if necessary. Of these aqueous media, it is preferable to use water (pure water, ion-exchanged water, tap water, etc.) from the viewpoint that contamination of unnecessary chemical species in preparation of a chromium plating solution or the like can be prevented.
生成する炭酸クロム(III)の溶解性は、炭酸塩水溶液及び三価のクロムを含む水溶液を同時添加することに加えて、反応液の温度にも影響される。ここで言う反応液とは、炭酸塩水溶液及び三価のクロムを含む水溶液が、水性媒体に添加されてなる液のことである。反応液の温度が５０℃よりも高いと、生成する炭酸クロム(III)が凝集体又は塊状になり易いことから、溶解性の高い炭酸クロムが得られない。反応液の温度が０℃未満であると、三価クロム塩及び／又は炭酸塩の析出のおそれがある。反応液の温度が１０〜５０℃、特に１０〜４０℃であると、溶解性の高い炭酸クロム(III)が一層容易に得られるので好ましい。 The solubility of the produced chromium (III) carbonate is influenced by the temperature of the reaction solution in addition to the simultaneous addition of the aqueous carbonate solution and the aqueous solution containing trivalent chromium. The reaction liquid here is a liquid obtained by adding an aqueous carbonate solution and an aqueous solution containing trivalent chromium to an aqueous medium. If the temperature of the reaction solution is higher than 50 ° C., the produced chromium carbonate (III) tends to be aggregates or lumps, so that highly soluble chromium carbonate cannot be obtained. If the temperature of the reaction solution is less than 0 ° C., trivalent chromium salt and / or carbonate may be precipitated. It is preferable that the temperature of the reaction solution is 10 to 50 ° C., particularly 10 to 40 ° C., because highly soluble chromium (III) carbonate can be obtained more easily.
炭酸塩水溶液と三価のクロムを含む水溶液との反応は中和反応であるので、両水溶液を水性媒体中で混合することで、所望の特性を有する炭酸クロム(III)が得られる。同時添加による反応中は、反応液を攪拌して反応を均一に行わせかつ反応を促進させることが好ましい。攪拌が不十分な場合には、反応液において局所的にアルカリの量に対して三価のクロムの量が過剰な状態になることがある。このような状態下に生成する炭酸クロム(III)は、酸性水溶液に対する溶解性に劣るものである。したがって、三価のクロムを含む水溶液の添加を、アルカリの量に対して三価のクロムの量が局所的に過剰にならないように行うことが重要である。この観点から、攪拌条件を、局所的な停滞部分の発生を避け、均一混合ができるように調整することが好ましい。アルカリの量に対して三価のクロムの量が局所的に過剰になる状態とは、例えば、特許文献４及び６並びに非特許文献１に記載されているように、三価のクロムを含む水溶液に無機アルカリ水溶液を添加した状態を言う。 Since the reaction between the carbonate aqueous solution and the aqueous solution containing trivalent chromium is a neutralization reaction, chromium (III) carbonate having desired characteristics can be obtained by mixing both aqueous solutions in an aqueous medium. During the reaction by simultaneous addition, it is preferable to stir the reaction solution to perform the reaction uniformly and to accelerate the reaction. If the stirring is insufficient, the amount of trivalent chromium may be excessive in the reaction solution with respect to the amount of alkali locally. Chromium (III) carbonate produced under such conditions is poor in solubility in acidic aqueous solutions. Therefore, it is important to add the aqueous solution containing trivalent chromium so that the amount of trivalent chromium is not locally excessive with respect to the amount of alkali. From this point of view, it is preferable to adjust the stirring conditions so as to avoid the occurrence of local stagnation and allow uniform mixing. The state in which the amount of trivalent chromium is locally excessive with respect to the amount of alkali is, for example, an aqueous solution containing trivalent chromium as described in Patent Documents 4 and 6 and Non-Patent Document 1. The state which added the inorganic alkaline aqueous solution to is said.
炭酸塩水溶液及び三価のクロムを含む水溶液の濃度及び添加比率は、炭酸塩水溶液と三価のクロムを含む水溶液との接触をｐＨ６以下に調整するために以下の範囲とすることが好ましい。濃度は、炭酸塩水溶液における炭酸イオンの濃度が０．０５〜５ｍｏｌ／ｌ、特に０．１〜３ｍｏｌ／ｌであることが好ましく、三価のクロムを含む水溶液における三価のクロムの濃度が０．０５〜５ｍｏｌ／ｌ、特に０．１〜３ｍｏｌ／ｌであることが好ましい。添加比率が、三価のクロムを含む水溶液中のＣｒに対する炭酸塩水溶液中のＣＯ３のモル比（ＣＯ３／Ｃｒ）が０．５〜２．０、更に１．０〜１．８、特に１．２〜１．７となる条件で添加を行うと、満足すべき結果が得られるので好ましい。 The concentration and the addition ratio of the aqueous carbonate solution and the aqueous solution containing trivalent chromium are preferably set to the following ranges in order to adjust the contact between the aqueous carbonate solution and the aqueous solution containing trivalent chromium to 6 or less. The concentration of carbonate ion in the carbonate aqueous solution is preferably 0.05 to 5 mol / l, particularly preferably 0.1 to 3 mol / l, and the concentration of trivalent chromium in the aqueous solution containing trivalent chromium is 0. 0.05 to 5 mol / l, particularly 0.1 to 3 mol / l is preferable. The molar ratio of CO 3 in the carbonate aqueous solution to the Cr in the aqueous solution containing trivalent chromium (CO 3 / Cr) is 0.5 to 2.0, more preferably 1.0 to 1.8. It is preferable to perform the addition under the conditions of 1.2 to 1.7 because satisfactory results can be obtained.
炭酸塩水溶液及び三価のクロムを含む水溶液の添加速度は、これらの水溶液を添加している間の反応液のｐＨが６以下、特に４〜６、とりわけ５以上６未満に維持されるように調整することが好ましい。反応中のｐＨをこの範囲内に維持することで、目的とする溶解性を有する炭酸クロム(III)を首尾よく製造することができる。 The addition rate of the aqueous carbonate solution and the aqueous solution containing trivalent chromium is such that the pH of the reaction solution is maintained at 6 or less, particularly 4 to 6, particularly 5 or more and less than 6 while these aqueous solutions are added. It is preferable to adjust. By maintaining the pH during the reaction within this range, chromium (III) carbonate having the desired solubility can be successfully produced.
三価のクロムを含む水溶液におけるクロム源としては、三価のクロムの水溶性塩を特に制限なく用いることができる。そのような塩としては、例えば塩化クロム、硫酸クロム、硫酸クロムアンモニウム、硫酸クロムカリウム、ギ酸クロム、フッ化クロム、過塩素酸クロム、スルファミン酸クロム、硝酸クロム、酢酸クロムなどが挙げられる。これらの塩は一種又は二種以上を組み合わせて用いることができる。これらの塩は、水溶液の状態で用いてもよく、あるいは粉末の状態で用いてもよい。例えば日本化学工業社製「３５％液体塩化クロム」、「４０％液体硫酸クロム」（製品名）や市販の硫酸クロム（結晶品）を用いることができる。これらの塩のうち、硫酸クロムを用いることが、目的とする溶解性を有する炭酸クロム(III)を容易に得られる点、有機物が残存しない点及び経済性の点から好ましい。 As a chromium source in an aqueous solution containing trivalent chromium, a water-soluble salt of trivalent chromium can be used without particular limitation. Examples of such salts include chromium chloride, chromium sulfate, chromium ammonium sulfate, chromium potassium sulfate, chromium formate, chromium fluoride, chromium perchlorate, chromium sulfamate, chromium nitrate, and chromium acetate. These salts can be used alone or in combination of two or more. These salts may be used in the form of an aqueous solution or in the form of a powder. For example, “35% liquid chromium chloride”, “40% liquid chromium sulfate” (product name) manufactured by Nippon Chemical Industry Co., Ltd., or commercially available chromium sulfate (crystal product) can be used. Of these salts, it is preferable to use chromium sulfate from the viewpoint of easily obtaining chromium (III) carbonate having the intended solubility, the point that no organic matter remains, and the economical point.
三価のクロムを含む水溶液としては、六価のクロムを含む水溶液における六価のクロムを三価に還元したものを用いることもできる。例えば重クロム酸塩の水溶液に亜硫酸ガスを通して六価のクロムを三価のクロムに還元した水溶液を用いることができる。あるいは、重クロム酸塩の水溶液に硫酸を加え、有機物で六価のクロムを三価のクロムに還元した水溶液を用いることもできる。 As the aqueous solution containing trivalent chromium, a solution obtained by reducing hexavalent chromium in an aqueous solution containing hexavalent chromium to trivalent can also be used. For example, an aqueous solution in which hexavalent chromium is reduced to trivalent chromium by passing sulfur dioxide into an aqueous solution of dichromate can be used. Alternatively, an aqueous solution in which sulfuric acid is added to an aqueous solution of dichromate and hexavalent chromium is reduced to trivalent chromium with an organic substance can be used.
三価のクロムを含む水溶液と同時に添加される炭酸塩水溶液に用いられる炭酸塩とは、狭義の炭酸塩及び炭酸水素塩を包含する広義の意味で用いられる。炭酸塩としては、炭酸のアルカリ金属塩やアンモニウム塩、重炭酸のアルカリ金属塩やアンモニウム塩等が挙げられる。具体的には、炭酸ナトリウム、炭酸カリウム、炭酸アンモニウム、炭酸水素ナトリウム、炭酸水素カリウム、炭酸水素アンモニウム等が挙げられる。 The carbonate used in the carbonate aqueous solution added simultaneously with the aqueous solution containing trivalent chromium is used in a broad sense including carbonate and hydrogen carbonate in a narrow sense. Examples of carbonates include alkali metal carbonates and ammonium salts of carbonic acid, and alkali metal salts and ammonium salts of bicarbonate. Specific examples include sodium carbonate, potassium carbonate, ammonium carbonate, sodium hydrogen carbonate, potassium hydrogen carbonate, ammonium hydrogen carbonate, and the like.
三価のクロムを含む水溶液と炭酸塩水溶液とを同時添加して炭酸クロム(III)が生成したら、スラリーを濾過して固形物としての炭酸クロム(III)を分離し、これを洗浄する。炭酸クロム(III)の生成からスラリーを濾過するまでは、極力短くすることが好ましい。換言すれば、生成した炭酸クロム(III)の熟成を極力行わないことが好ましい。本発明においては、三価のクロムを含む水溶液と炭酸塩水溶液とを同時添加したときは、ｐＨが６以下に保持されている。しかし、生成物を熟成させることにより原料由来の炭酸成分が炭酸クロム(III)に配位していく過程で、水酸化物イオンを放出するためｐＨが上昇してしまい、目的とする溶解性を有する炭酸クロム(III)を製造しにくくなるので、熟成を極力行わず、速やかに生成物を濾過することが好ましい。 When an aqueous solution containing trivalent chromium and an aqueous carbonate solution are added at the same time to produce chromium (III) carbonate, the slurry is filtered to separate chromium (III) carbonate as a solid and washed. From the production of chromium (III) carbonate to the filtration of the slurry, it is preferable to make it as short as possible. In other words, it is preferable not to age the produced chromium carbonate (III) as much as possible. In the present invention, when an aqueous solution containing trivalent chromium and an aqueous carbonate solution are added simultaneously, the pH is maintained at 6 or less. However, in the process where the carbonic acid component derived from the raw material is coordinated to chromium (III) by aging the product, the pH rises due to the release of hydroxide ions, and the desired solubility is achieved. It is difficult to produce chromium (III) carbonate, and therefore it is preferable to filter the product promptly without aging as much as possible.
濾過には通常の方法を用いることができる。例えばブフナー漏斗を用いた吸引濾過を行うことができる。濾過後の洗浄は水を用いて行う。例えばブフナー漏斗上のケーキに水を加えてリパルプし、更に吸引濾過を行う等して洗浄を行うことができる。 A usual method can be used for filtration. For example, suction filtration using a Buchner funnel can be performed. Washing after filtration is performed using water. For example, washing can be performed by adding water to the cake on the Buchner funnel for repulping and further performing suction filtration.
洗浄は、濾液の導電率が例えば５ｍＳ／ｃｍ以下となるまで行うことが好ましい。濾液の導電率が高いことは、洗浄後の炭酸クロム(III)に原料に由来する副生塩が多く残存していることを意味する。かかる副生塩は、炭酸クロム(III)を三価クロムめっき液のクロム源として用いた場合に、めっき液中に蓄積されてしまうので極力除去されるべきものである。したがって濾液の導電率が前記の値以下となるまで洗浄を行うことが好ましい。 The washing is preferably performed until the conductivity of the filtrate is, for example, 5 mS / cm or less. A high conductivity of the filtrate means that a large amount of by-product salt derived from the raw material remains in the washed chromium (III) carbonate. Such a by-product salt should be removed as much as possible because it accumulates in the plating solution when chromium (III) carbonate is used as the chromium source of the trivalent chromium plating solution. Therefore, it is preferable to perform washing until the filtrate has a conductivity of not more than the above value.
また、濾過及び洗浄は、好ましくは０〜５０℃、更に好ましくは２０〜４０℃の低温で行うことが好ましい。クロムのオール化やオクソ化及びそれに起因する難溶性物の生成を防止することができるからである。 Moreover, it is preferable to perform filtration and washing at a low temperature of preferably 0 to 50 ° C, more preferably 20 to 40 ° C. This is because it is possible to prevent the formation or formation of chromium and the formation of poorly soluble substances resulting therefrom.
洗浄後、炭酸クロム(III)を乾燥させる。この乾燥は、酸に対する溶解性を高くする観点から、炭酸クロム(III)を１１０℃で２時間乾燥したときの乾燥減量が２０質量％以上となるようにする。乾燥減量の値は高ければ高いほど好ましいが、例えば５５質量％程度、特に３５質量％程度に乾燥減量の値が高ければ、酸に対する満足すべき溶解性が得られる。この観点から、乾燥減量は、好ましくは２５質量％以上５５質量％以下、更に好ましくは２５質量％以上３５質量％以下となるようにする。 After washing, the chromium (III) carbonate is dried. This drying is performed so that the loss on drying when chromium (III) carbonate is dried at 110 ° C. for 2 hours is 20% by mass or more from the viewpoint of increasing the acid solubility. The higher the value of loss on drying, the better. However, if the value of loss on drying is, for example, about 55% by mass, especially about 35% by mass, satisfactory solubility in acid can be obtained. From this viewpoint, the loss on drying is preferably 25% by mass to 55% by mass, and more preferably 25% by mass to 35% by mass.
本発明の炭酸クロム(III)は、これを乾燥した粉末状態で、大気下で保存しても、そのままの粉末状態で酸に対する溶解性が高いという利点を有している。粉末状態で保存できることは、スラリーの状態で保存するよりも、取り扱い性や搬送性に優れる点で有利である。 The chromium (III) carbonate of the present invention has an advantage that it is highly soluble in an acid in the powder state as it is even when stored in the air in a dry powder state. The fact that it can be stored in a powdered state is advantageous in that it is excellent in handleability and transportability as compared with storing in a slurry state.
前記の反応中に、又は反応終了後に、還元剤を添加することが好ましい。これによって反応中に、又は保存中に（スラリー状態での保存中に）、酸化雰囲気下に置かれた場合でも、再酸化を防止できることから、六価のクロムが生成することを防止できる。特に、反応終了後に還元剤を添加することが、再酸化を確実に防止できる観点から好ましい。還元剤としては、当該技術分野において従来用いられている有機系又は無機系の還元剤を特に制限なく用いることができる。有機系の還元剤としては、例えばメチルアルコール、プロピルアルコール等の一価アルコール、エチレングリコール、プロピレングリコール等の二価アルコールが好適に使用される。他の有機系の還元剤としては、グルコースなどの単糖類、マルトースなどの二糖類、でんぷんなどの多糖類等が挙げられる。無機系の還元剤としては、例えばチオ硫酸ナトリウム、ヒドラジン、過酸化水素等が挙げられる。 It is preferable to add a reducing agent during or after the reaction. Accordingly, even when placed in an oxidizing atmosphere during the reaction or during storage (during storage in a slurry state), reoxidation can be prevented, so that hexavalent chromium can be prevented from being generated. In particular, it is preferable to add a reducing agent after completion of the reaction from the viewpoint of reliably preventing reoxidation. As the reducing agent, an organic or inorganic reducing agent conventionally used in the technical field can be used without particular limitation. As the organic reducing agent, for example, monohydric alcohols such as methyl alcohol and propyl alcohol, and dihydric alcohols such as ethylene glycol and propylene glycol are preferably used. Other organic reducing agents include monosaccharides such as glucose, disaccharides such as maltose, polysaccharides such as starch, and the like. Examples of the inorganic reducing agent include sodium thiosulfate, hydrazine, hydrogen peroxide, and the like.
このようにして得られた炭酸クロム(III)は、酸性水溶液に溶解性が高いので、粉末状態のまま、又は水を加えてスラリーの状態として、酸性水溶液に添加して溶解させることができ、それによって対応する酸の塩（無機酸クロム(III)又は有機酸クロム(III)）の水溶液を容易に得ることができる。酸水溶液の濃度等は使用する酸の種類及び用途に応じて、適宜決定することができる。 The chromium (III) carbonate thus obtained is highly soluble in an acidic aqueous solution, so that it can be dissolved in an acidic aqueous solution in a powder state or as a slurry state by adding water, Thereby, an aqueous solution of a corresponding acid salt (inorganic acid chromium (III) or organic acid chromium (III)) can be easily obtained. The concentration of the acid aqueous solution and the like can be appropriately determined according to the type and use of the acid used.
前記の酸性水溶液としては、無機酸又は有機酸の水溶液が用いられる。無機酸水溶液としては、例えば硝酸、リン酸、塩酸、硫酸、フッ化水素酸等の無機酸の水溶液が挙げられる。有機酸水溶液としては、ギ酸、酢酸、グリコール酸、乳酸、グルコン酸、シュウ酸、マレイン酸、マロン酸、リンゴ酸、酒石酸、コハク酸、クエン酸、フマル酸、酪酸等の有機酸の水溶液が挙げられる。 As the acidic aqueous solution, an aqueous solution of an inorganic acid or an organic acid is used. Examples of the inorganic acid aqueous solution include aqueous solutions of inorganic acids such as nitric acid, phosphoric acid, hydrochloric acid, sulfuric acid, and hydrofluoric acid. Examples of the organic acid aqueous solution include aqueous solutions of organic acids such as formic acid, acetic acid, glycolic acid, lactic acid, gluconic acid, oxalic acid, maleic acid, malonic acid, malic acid, tartaric acid, succinic acid, citric acid, fumaric acid, and butyric acid. It is done.
炭酸クロム(III)を容易にかつ確実に溶解する観点からは、無機酸水溶液又は有機酸水溶液はｐＨが低いことが好ましい。具体的には好ましくはｐＨ２以下、更に好ましくはｐＨ１以下である。無機酸水溶液又は有機酸水溶液における無機酸又は有機酸の濃度は、１〜５０質量％、特に５〜５０質量％の範囲であることが好ましい。また、容易にかつ確実に溶解させる観点からは、無機酸水溶液又は有機酸水溶液１リットルに対し、Ｃｒとして１ｇ以下に相当する炭酸クロム(III)を使用することが好ましい。 From the viewpoint of easily and reliably dissolving chromium (III) carbonate, the aqueous inorganic acid solution or aqueous organic acid solution preferably has a low pH. Specifically, the pH is preferably 2 or less, more preferably pH 1 or less. The concentration of the inorganic acid or organic acid in the inorganic acid aqueous solution or organic acid aqueous solution is preferably in the range of 1 to 50% by mass, particularly 5 to 50% by mass. Further, from the viewpoint of easily and reliably dissolving, it is preferable to use chromium (III) carbonate corresponding to 1 g or less as Cr with respect to 1 liter of the inorganic acid aqueous solution or the organic acid aqueous solution.
無機酸水溶液又は有機酸水溶液への炭酸クロム(III)の溶解は、２５〜９０℃で行うことが好ましい。 The dissolution of chromium (III) carbonate in the aqueous inorganic acid solution or the aqueous organic acid solution is preferably performed at 25 to 90 ° C.
このようにして得られた無機酸クロムとしては、塩酸クロム、硝酸クロム、リン酸クロム、硫酸クロム、フッ化クロム等が挙げられる。これらの無機酸クロムは、塩基性塩であってもよい。例えば硝酸クロムは、組成式Ｃｒ（ＯＨ）ｘ（ＮＯ３）ｙ（式中、０≦ｘ≦２、１≦ｙ≦３、ｘ＋ｙ＝３）で表される化合物であり、該化合物には、Ｃｒ（ＮＯ３）３で表される正塩である硝酸クロムの他に、Ｃｒ（ＯＨ）０．５（ＮＯ３）２．５、Ｃｒ（ＯＨ）（ＮＯ３）２、Ｃｒ（ＯＨ）２（ＮＯ３）等の塩基性硝酸クロムも含まれる。 Examples of the inorganic acid chromium thus obtained include chromium hydrochloride, chromium nitrate, chromium phosphate, chromium sulfate, and chromium fluoride. These inorganic acid chromium may be a basic salt. For example, chromium nitrate is a compound represented by the composition formula Cr (OH) x (NO 3 ) y (where 0 ≦ x ≦ 2, 1 ≦ y ≦ 3, x + y = 3). In addition to chromium nitrate, which is a normal salt represented by Cr (NO 3 ) 3 , Cr (OH) 0.5 (NO 3 ) 2.5 , Cr (OH) (NO 3 ) 2 , Cr (OH) 2 Basic chromium nitrate such as (NO 3 ) is also included.
また有機酸クロムは、一般式Ｃｒｍ（Ａｘ）ｎで表される化合物である。前記の一般式中、Ａは有機酸からプロトンを除いた残基を示す。Ａは負の電荷を有している。ｘはＡの電荷（負電荷）を表す。ｍ及びｎは３ｍ＋ｘｎ＝０を満たす整数をそれぞれ表す。 The organic acid chromium salt is a compound represented by the general formula Cr m (A x) n. In said general formula, A shows the residue remove | excluding the proton from the organic acid. A has a negative charge. x represents the charge of A (negative charge). m and n each represent an integer satisfying 3m + xn = 0.
有機酸クロムにおける有機酸は、Ｒ（ＣＯＯＨ）ｙで表される。式中、Ｒは有機基、水素原子又は単結合若しくは二重結合を表す。ｙは有機酸におけるカルボキシル基の数を表し、１以上の整数であるが、好ましくは１ないし３である。前記の一般式におけるＡはＲ（ＣＯＯ−）ｙで表される。Ｒが有機基である場合、該有機基としては炭素数１〜１０、特に１〜５の脂肪族基が好ましい。この脂肪族基は、他の官能基、例えば水酸基で置換されていてもよい。脂肪族基としては、飽和脂肪族基及び不飽和脂肪族基のいずれも用いることができる。 The organic acid in the organic acid chromium is represented by R (COOH) y . In the formula, R represents an organic group, a hydrogen atom, a single bond or a double bond. y represents the number of carboxyl groups in the organic acid and is an integer of 1 or more, preferably 1 to 3. A in the above general formula is represented by R (COO − ) y . When R is an organic group, the organic group is preferably an aliphatic group having 1 to 10 carbon atoms, particularly 1 to 5 carbon atoms. This aliphatic group may be substituted with another functional group such as a hydroxyl group. As the aliphatic group, any of a saturated aliphatic group and an unsaturated aliphatic group can be used.
また、本発明の方法に従い製造された炭酸クロム(III)は、粉末状態のまま、又は水を加えてスラリーの状態として、２種以上の酸を含む水溶液に添加して溶解し、クロム(III)源を含む水溶液とすることもできる。炭酸クロム(III)及び酸水溶液の濃度及び使用量、使用する酸の組み合わせ、各酸の配合割合は、目的とするクロム(III)源の種類及び用途に応じて、適宜決定することができる。 Further, the chromium (III) carbonate produced according to the method of the present invention is dissolved in an aqueous solution containing two or more acids in a powder state or in a slurry state by adding water to a chromium (III) It can also be an aqueous solution containing a source. The concentration and amount of the chromium (III) carbonate and the acid aqueous solution, the combination of the acids to be used, and the mixing ratio of each acid can be appropriately determined according to the type and application of the target chromium (III) source.
炭酸クロム(III)を溶解する酸水溶液の種類は、有機酸どうしの組み合わせ、無機酸どうしの組み合わせ、あるいは有機酸と無機酸の両方を含む水溶液であってもよい。使用できる有機酸及び無機酸としては、先に述べたものと同様のものが挙げられる。 The type of the acid aqueous solution that dissolves chromium (III) carbonate may be a combination of organic acids, a combination of inorganic acids, or an aqueous solution containing both organic and inorganic acids. Examples of the organic acid and inorganic acid that can be used include those described above.
本発明のクロム(III)源を含む２種以上の酸水溶液の製造方法は、上述した無機酸クロム又は有機酸クロム水溶液の製造方法に従えばよいので、ここではその詳細な説明を省略する。概略を観点に説明すると、炭酸クロム(III)の酸水溶液への溶解には、例えば次の１）〜３）の方法を用いることができる。しかし、これらの方法に制限されるものではない。
１）所望の２種以上の酸を予め溶解した酸水溶液を調製し、これに炭酸クロム(III)を添加して炭酸クロム(III)を酸溶液に溶解処理する方法。
２）所望の酸のうちの１成分の酸を予め適宜選択し、次にこの選択した酸を水に溶解し酸水溶液を調製する。次に得られた酸水溶液に炭酸クロム(III)を添加し１次溶解処理をする。これに残りの成分の酸を添加して第２次溶解処理をする方法。
３）あるいは所望の２種以上の酸の必要量の一部を予め水に溶解した酸水溶液を調製する。次に得られた酸水溶液に炭酸クロム(III)を添加し１次溶解処理をする。これに残量の酸を添加して２次溶解処理し炭酸クロム(III)を溶解する方法。
Since the method for producing two or more acid aqueous solutions containing a chromium (III) source of the present invention may be in accordance with the method for producing an inorganic acid chromium or organic acid chromium aqueous solution described above, detailed description thereof is omitted here. To explain the outline, the following methods 1) to 3) can be used for dissolving chromium (III) carbonate in an acid aqueous solution. However, it is not limited to these methods.
1) A method in which an acid aqueous solution in which two or more kinds of desired acids are dissolved in advance is prepared, and chromium (III) carbonate is added thereto, and chromium (III) carbonate is dissolved in the acid solution.
2) One component acid of the desired acids is appropriately selected in advance, and then the selected acid is dissolved in water to prepare an aqueous acid solution. Next, chromium (III) carbonate is added to the resulting acid aqueous solution to perform a primary dissolution treatment. A method of performing a secondary dissolution treatment by adding the remaining acid component.
3) Alternatively, an acid aqueous solution in which a part of a necessary amount of two or more desired acids is dissolved in water in advance is prepared. Next, chromium (III) carbonate is added to the resulting acid aqueous solution to perform a primary dissolution treatment. A method of dissolving the chromium (III) carbonate by adding a remaining amount of acid to this and performing a secondary dissolution treatment.
かくして得られる本発明のクロム(III)源は、以下の式で表される、クロムと結合する酸根が２種以上の複合クロム(III)塩である。なお、クロムと結合する酸の種類は、有機酸どうしの組み合わせ、無機酸どうしの組み合わせ、あるいは有機酸と無機酸の両方から選ばれるものであってもよい。 The chromium (III) source of the present invention thus obtained is a composite chromium (III) salt having two or more acid radicals bonded to chromium represented by the following formula. In addition, the kind of acid couple | bonded with chromium may be chosen from the combination of organic acids, the combination of inorganic acids, or both organic acids and inorganic acids.
前記の式において、酸としてリン酸を用いた場合の前記Ｈ２ＰＯ４ −とＨＰＯ４ ２−の存在割合は、反応条件や原料系等で任意に変化する。 In the above formula, when phosphoric acid is used as the acid, the abundance ratio of H 2 PO 4 — and HPO 4 2− varies arbitrarily depending on reaction conditions, raw material systems, and the like.
本発明の炭酸クロム(III)は、上述のとおり酸性水溶液に溶解性が高いので、以下に述べるように、例えば三価のクロムを用いたクロムめっき液や三価クロム化成処理液などの金属の表面処理液における三価クロム源として有用である。本発明の炭酸クロム(III)を三価クロム源として用いることで、めっき液や処理液の調製時間を短縮化することが可能となる。また、めっき液や処理液中に未溶解の炭酸クロム(III)が存在しないので、良質なめっき皮膜や三価クロム皮膜を形成することができる。 Since the chromium (III) carbonate of the present invention is highly soluble in an acidic aqueous solution as described above, as described below, for example, a chromium plating solution using trivalent chromium or a trivalent chromium chemical conversion treatment solution such as a trivalent chromium chemical conversion treatment solution. It is useful as a trivalent chromium source in the surface treatment solution. By using the chromium (III) carbonate of the present invention as a trivalent chromium source, it is possible to shorten the preparation time of the plating solution and the treatment solution. In addition, since there is no undissolved chromium (III) carbonate in the plating solution or the treatment solution, a high-quality plating film or trivalent chromium film can be formed.
本発明によれば、上述した溶解性の高い炭酸クロム(III)をクロム源として用いた三価クロム含有液も提供される。本発明の炭酸クロム(III)含有液は、装飾用の最終仕上げ及び工業用の三価クロムめっきに用いられる。また、基体となる金属の表面や、基体となるプラスチックに形成されたニッケルめっきの表面などを始めとする金属の表面に施されるめっき等の各種金属の表面処理に用いられる。更に亜鉛めっきやすずめっき等のめっきの表面を対象とした三価クロム化成処理に用いられる。すなわち、本発明の三価クロム含有液は、三価クロムめっき液や三価クロムの化成処理液であり得る。以下の説明では、特に断らない限り、これらの液を総称して「めっき液等」と言う。 According to the present invention, a trivalent chromium-containing liquid using the above-described highly soluble chromium (III) carbonate as a chromium source is also provided. The chromium (III) carbonate-containing liquid of the present invention is used for decorative final finishing and industrial trivalent chromium plating. Further, it is used for surface treatment of various metals such as plating applied to the surface of a metal such as a surface of a metal serving as a base and a surface of nickel plating formed on a plastic serving as a base. Furthermore, it is used for trivalent chromium chemical conversion treatment for the surface of plating such as galvanization and tin plating. That is, the trivalent chromium-containing liquid of the present invention can be a trivalent chromium plating solution or a trivalent chromium chemical conversion treatment solution. In the following description, these solutions are collectively referred to as “plating solutions and the like” unless otherwise specified.
本発明の三価クロム含有液を三価クロムめっき液として用いる場合、該三価クロムめっき液は、上述の炭酸クロム(III)に由来する三価のクロム及び有機酸等を始めとする他の成分を含むものである。また本発明の三価クロム含有液を三価クロム化成処理用の処理液として用いる場合には、該処理液は、クロム源として上述の炭酸クロム(III)を用い、更にコバルト化合物、珪素化合物、亜鉛化合物、種々の有機酸等を含むことができる。 When the trivalent chromium-containing solution of the present invention is used as a trivalent chromium plating solution, the trivalent chromium plating solution is a trivalent chromium derived from the above-mentioned chromium (III) carbonate and other organic acids such as organic acids. Contains ingredients. When the trivalent chromium-containing liquid of the present invention is used as a treatment liquid for trivalent chromium chemical conversion treatment, the treatment liquid uses the above-mentioned chromium (III) carbonate as a chromium source, and further a cobalt compound, a silicon compound, Zinc compounds, various organic acids and the like can be included.
前記の三価クロム化成処理液に用いられるコバルト化合物としては、塩化コバルト、硝酸コバルト、硫酸コバルト、リン酸コバルト、酢酸コバルト等が挙げられる。これらは１種又は２種以上を混合して用いることもできる。珪素化合物としては、コロイダルシリカ、珪酸ソーダ、珪酸カリ、珪酸リチウムが挙げられる。これらの珪素化合物は１種又は２種以上を混合して用いることもできる。亜鉛化合物としては、塩化亜鉛、硫酸亜鉛、硝酸亜鉛、酸化亜鉛、炭酸亜鉛、リン酸亜鉛、酢酸亜鉛等が挙げられる。これらの亜鉛化合物は１種又は２種以上を混合して用いることもできる。有機酸としては、シュウ酸、マロン酸、コハク酸、クエン酸、アジピン酸、酒石酸、リンゴ酸、グリシン等が挙げられる。これらはキレート作用を示すことから、めっき液中で三価のクロムを安定な形に保持することができると考えられる。 Examples of the cobalt compound used in the trivalent chromium chemical conversion treatment liquid include cobalt chloride, cobalt nitrate, cobalt sulfate, cobalt phosphate, and cobalt acetate. These can also be used 1 type or in mixture of 2 or more types. Examples of the silicon compound include colloidal silica, sodium silicate, potassium silicate, and lithium silicate. These silicon compounds can be used alone or in combination of two or more. Examples of the zinc compound include zinc chloride, zinc sulfate, zinc nitrate, zinc oxide, zinc carbonate, zinc phosphate, and zinc acetate. These zinc compounds can be used alone or in combination. Examples of the organic acid include oxalic acid, malonic acid, succinic acid, citric acid, adipic acid, tartaric acid, malic acid, glycine and the like. Since these show chelate action, it is considered that trivalent chromium can be held in a stable form in the plating solution.
前記の三価クロム化成処理液は、クロムを例えば０．００５〜１．０モル／リットル含むことが好ましい。クロムと有機酸のモル比は、クロム１モルに対して１〜５モルであることが好ましい。 The trivalent chromium chemical conversion treatment liquid preferably contains chromium, for example, 0.005 to 1.0 mol / liter. The molar ratio of chromium to organic acid is preferably 1 to 5 mol with respect to 1 mol of chromium.
本発明によれば、上述のめっき液等に加えて、クロムめっきや三価クロム化成処理などの金属の表面処理に用いられるめっき液等の補充液も提供される。この補充液は、上述の炭酸クロム(III)を含むスラリーからなる。このスラリーには、上述のとおり不純物イオンが含まれていないことが好ましい。クロムめっきや三価クロム化成処理等においては、無機アニオン、例えば硫酸イオン、硝酸イオン、塩化物イオンなどは、皮膜中に取り込まれず液中に残存したままになる。したがって、めっき液等にクロム源を注ぎ足すと、そのクロム源の対アニオンである無機アニオンがめっき液等中に次第に蓄積していき、めっき液等の組成が変化してしまう。これに対して、上述の炭酸クロム(III)を含むスラリーからなる補充液は、これらのアニオンを含まないので、該補充液をクロム供給源としてめっき液等に注ぎ足しても、めっき液等の組成の変化が少ない。その結果、めっき液等を頻繁に更新することなく、長期にわたりめっき液等を用いることができる。 According to the present invention, in addition to the above-described plating solution and the like, a replenishing solution such as a plating solution used for metal surface treatment such as chromium plating and trivalent chromium chemical conversion treatment is also provided. This replenisher consists of a slurry containing chromium (III) carbonate. As described above, this slurry preferably does not contain impurity ions. In chromium plating, trivalent chromium conversion treatment, and the like, inorganic anions such as sulfate ions, nitrate ions, and chloride ions are not taken into the film and remain in the liquid. Therefore, when a chromium source is added to a plating solution or the like, an inorganic anion that is a counter anion of the chromium source gradually accumulates in the plating solution or the like, and the composition of the plating solution or the like changes. On the other hand, since the replenisher composed of the above-mentioned slurry containing chromium (III) carbonate does not contain these anions, even if the replenisher is added to the plating solution as a chromium supply source, Little change in composition. As a result, the plating solution or the like can be used over a long period of time without frequently updating the plating solution or the like.
前記の補充液によってクロム源が補充されるめっき液等の種類に特に制限はなく、従来用いられてきた三価のクロムを含有するめっき液等を用いることができる。 There are no particular restrictions on the type of plating solution that is replenished with the chromium source by the replenishing solution, and a plating solution containing trivalent chromium that has been conventionally used can be used.
本発明の補充液は、クロムめっきや三価クロム化成処理を行っている間、めっき液等中のクロムイオンの消耗の程度に応じて該めっき液等中に適量添加される。添加は連続的でもよく、あるいは断続的でもよい。 An appropriate amount of the replenisher of the present invention is added to the plating solution or the like according to the degree of consumption of chromium ions in the plating solution or the like during the chromium plating or trivalent chromium conversion treatment. The addition may be continuous or intermittent.
以上、本発明をその好ましい実施形態に基づき説明したが、本発明は前記実施形態に制限されず、当該技術分野に属する通常の知識を有する者の常識の範囲内において種々の改変を行うことは何ら妨げられない。またそのような改変は本発明の範囲内のものである。 The present invention has been described above based on the preferred embodiments. However, the present invention is not limited to the above-described embodiments, and various modifications may be made within the common sense of persons having ordinary knowledge in the technical field. I can't prevent anything. Such modifications are also within the scope of the present invention.
以下に実施例を挙げて本発明を具体的に説明する。特に断らない限り「％」は「質量％」を意味する。また、例中の測定は以下の方法で行った。
＜体積平均粒子径（ＭＶ）及び平均粒子径（Ｄ）＞
炭酸クロム(III)を家庭用ミキサーで水中に十分分散した後、レーザー回折散乱法により測定した。
＜Ｃｒ２Ｏ３量＞
試料を酸に溶解した溶液を、ＩＣＰ発光分光分析装置（（株）島津製作所製、ＩＣＰＳ‐８１００ＣＬ）によってＣｒを測定し、得られた値をＣｒ２Ｏ３として換算した。
＜ＣＯ２量＞
全有機炭素（ＴＯＣ）分析装置（（株）島津製作所製、ＳＳＭ−５０００Ａ）を用い、試料を９５０℃に加熱することで、生成・遊離したＣＯ２を赤外線ガス検出装置（（株）島津製作所製、ＴＯＣ−Ｖ ＣＰＨ）にて測定した。
＜ＯＨ量＞
試料の乾燥減量（％）を測定し、１００−Ｃｒ２Ｏ３（％）−ＣＯ２（％）−Ｓ（％）−乾燥減量（％）から算出した。
＜Ｓ量＞
試料を酸に溶解した溶液を、ＩＣＰ発光分光分析装置（（株）島津製作所製、ＩＣＰＳ−８１００ＣＬ）によってＳを定量した。
＜乾燥減量＞
試料を乾燥機中で１１０℃で２時間乾燥する前後の重量を測定しておき、乾燥前の重量から乾燥後の重量を差し引いた値を、乾燥前の重量で除して百分率に換算することで求めた。
＜ＣＯ２／Ｃｒモル比＞
前記Ｃｒ２Ｏ３量と前記ＣＯ２量の測定結果からＣＯ２／Ｃｒモル比として算出した。
The present invention will be specifically described below with reference to examples. Unless otherwise specified, “%” means “mass%”. Moreover, the measurement in an example was performed with the following method.
<Volume average particle diameter (MV) and average particle diameter (D)>
Chromium (III) carbonate was sufficiently dispersed in water with a home mixer, and then measured by a laser diffraction scattering method.
<Cr 2 O 3 amount>
A solution prepared by dissolving a sample in acid, ICP emission spectrophotometer (manufactured by Shimadzu Corporation, ICPS-8100CL) was measured Cr by the obtained value was calculated as Cr 2 O 3.
<CO 2 amount>
Using a total organic carbon (TOC) analyzer (SSM-5000A, manufactured by Shimadzu Corporation), the sample was heated to 950 ° C., and the generated and liberated CO 2 was detected by an infrared gas detector (Shimadzu Corporation). Manufactured by TOC-V CPH).
<OH amount>
The loss on drying (%) of the sample was measured and calculated from 100-Cr 2 O 3 (%)-CO 2 (%)-S (%)-loss on drying (%).
<S amount>
S was quantified for the solution which melt | dissolved the sample in the acid by the ICP emission-spectral-analysis apparatus (Corporation | KK Shimadzu Corp. make, ICPS-8100CL).
<Loss on drying>
Measure the weight before and after drying the sample at 110 ° C. for 2 hours in a dryer, and convert the value obtained by subtracting the weight after drying from the weight before drying to the percentage before drying. I asked for it.
<CO 2 / Cr molar ratio>
The CO 2 / Cr molar ratio was calculated from the measurement results of the Cr 2 O 3 amount and the CO 2 amount.
［実施例１］
１０％炭酸ナトリウム水溶液５００ｇと、４０％硫酸クロム水溶液（日本化学工業株式会社製）１４７．３ｇをそれぞれ容器に入れ準備した。次に１０％炭酸ナトリウム水溶液を２０℃に調整し、また４０％硫酸クロム水溶液を純水で希釈して２５％硫酸クロム水溶液とし、これを２０℃に調整した。２０℃に調整した純水中に、炭酸ナトリウム水溶液と硫酸クロム水溶液を同時添加した。添加速度は、炭酸ナトリウム水溶液が８．３ｇ／分、硫酸クロム水溶液が３．９ｇ／分であった。このときのＣｒに対するＣＯ３の仕込モル比（ＣＯ３／Ｃｒ）は１．５６であった。添加は連続的に６０分間行った。添加の間、反応液のｐＨは約５．９に維持されていた。また、添加の間、反応液の温度は２０〜３０℃の間に維持されていた。また、添加の間、反応液を攪拌（３５０ｒｐｍ）して、炭酸ナトリウムの量に対して硫酸クロムの量が局所的に過剰にならないようにした。反応によって生成した沈殿を、濾液の導電率が１ｍＳ／ｃｍになるまで３０℃で濾過水洗し、炭酸クロム(III)ケーキを得た。この炭酸クロム(III)ケーキを、７０℃で１２時間にわたり真空乾燥させた。得られた炭酸クロム(III)の測定結果は表１に示すとおりであった。また、温度２５℃でｐＨが３．０のフッ酸水溶液１リットルに、Ｃｒとして１ｇ含有に相当する炭酸クロム(III)を加えたときの溶解性（炭酸クロム(III)の生成直後及び９０日保存した後、マグネチックスターラの回転数：２００ｒｐｍ）は表１に示すとおりであった。
[Example 1]
A 10% aqueous sodium carbonate solution (500 g) and a 40% chromium sulfate aqueous solution (manufactured by Nippon Chemical Industry Co., Ltd.) (147.3 g) were prepared in respective containers. Next, a 10% sodium carbonate aqueous solution was adjusted to 20 ° C., and a 40% chromium sulfate aqueous solution was diluted with pure water to obtain a 25% chromium sulfate aqueous solution, which was adjusted to 20 ° C. A sodium carbonate aqueous solution and a chromium sulfate aqueous solution were simultaneously added to pure water adjusted to 20 ° C. The addition rate was 8.3 g / min for an aqueous sodium carbonate solution and 3.9 g / min for an aqueous chromium sulfate solution. Molar ratio of CO 3 for Cr at this time (CO 3 / Cr) was 1.56. The addition was continuously performed for 60 minutes. During the addition, the pH of the reaction solution was maintained at about 5.9. Moreover, the temperature of the reaction liquid was maintained between 20-30 degreeC during addition. During the addition, the reaction solution was stirred (350 rpm) so that the amount of chromium sulfate was not locally excessive with respect to the amount of sodium carbonate. The precipitate formed by the reaction was washed with filtered water at 30 ° C. until the filtrate had a conductivity of 1 mS / cm to obtain a chromium (III) carbonate cake. The chromium (III) carbonate cake was vacuum dried at 70 ° C. for 12 hours. The measurement results of the obtained chromium (III) carbonate were as shown in Table 1. Further, solubility when chromium (III) equivalent to 1 g of Cr is added to 1 liter of hydrofluoric acid aqueous solution having a pH of 3.0 at a temperature of 25 ° C. After storage, the rotational speed of the magnetic stirrer: 200 rpm was as shown in Table 1.
［実施例２］
４０％硫酸クロム水溶液の添加量を２４１．３ｇとし，また添加速度を硫酸クロム水溶液が６．５ｇ／分とし、ｐＨを約５に維持した以外は実施例１と同じ方法で行った。このときのＣｒに対するＣＯ３の仕込モル比（ＣＯ３／Ｃｒ）は０．９４であった。得られた炭酸クロム(III)について、実施例１と同様の測定を行った。その結果を表１に示す。
[Example 2]
The same procedure as in Example 1 was performed except that the addition amount of the 40% chromium sulfate aqueous solution was 241.3 g, the addition rate was 6.5 g / min for the chromium sulfate aqueous solution, and the pH was maintained at about 5. Molar ratio of CO 3 for Cr at this time (CO 3 / Cr) was 0.94. The obtained chromium (III) carbonate was measured in the same manner as in Example 1. The results are shown in Table 1.
［実施例３］
炭酸クロム（III）ケーキを、７０℃で１５時間にわたり真空乾燥させたこと以外は実施例１と同じ方法で行った。このときのＣｒに対するＣＯ３の仕込モル比（ＣＯ３／Ｃｒ）は１．５６であった。得られた炭酸クロム(III)について、実施例１と同様の測定を行った。その結果を表１に示す。
[Example 3]
The same procedure as in Example 1 was followed, except that the chromium (III) carbonate cake was vacuum dried at 70 ° C. for 15 hours. Molar ratio of CO 3 for Cr at this time (CO 3 / Cr) was 1.56. The obtained chromium (III) carbonate was measured in the same manner as in Example 1. The results are shown in Table 1.
［比較例１］
１０％炭酸ナトリウム水溶液５００ｇと、４０％硫酸クロム水溶液（日本化学工業株式会社製）１０８．７ｇをそれぞれ容器に入れ準備した。次に１０％炭酸ナトリウム水溶液を２０℃に調整し、また４０％硫酸クロム水溶液を純水で希釈して２５％硫酸クロム水溶液とし、これを２０℃に調整した。２０℃に調整した純水中に、炭酸ナトリウム水溶液と硫酸クロム水溶液を同時添加した。添加速度は、炭酸ナトリウム水溶液が８．３ｇ／分、硫酸クロム水溶液が２．９ｇ／分であった。このときのＣｒに対するＣＯ３の仕込モル比（ＣＯ３／Ｃｒ）は２．０８であった。添加は連続的に６０分間行った。添加の間、反応液のｐＨは約７に維持されていた。また、添加の間、反応液の温度は２０〜３０℃の間に維持されていた。また、添加の間、反応液を撹拌（３５０ｒｐｍ）して、炭酸ナトリウムの量に対して硫酸クロムの量が局所的に過剰にならないようにした。反応によって生成した沈殿を、濾液の導電率が１ｍＳ／ｃｍになるまで３０℃で濾過水洗し、炭酸クロム（III）ケーキを得た。この炭酸クロム（III）ケーキを、７０℃で１２時間にわたり真空乾燥させた。得られた炭酸クロム(III)について、実施例と同様の測定を行った。その結果を表２に示す。
[Comparative Example 1]
A 10% aqueous sodium carbonate solution (500 g) and a 40% chromium sulfate aqueous solution (manufactured by Nippon Kagaku Kogyo Co., Ltd.) (108.7 g) were prepared in respective containers. Next, a 10% sodium carbonate aqueous solution was adjusted to 20 ° C., and a 40% chromium sulfate aqueous solution was diluted with pure water to obtain a 25% chromium sulfate aqueous solution, which was adjusted to 20 ° C. A sodium carbonate aqueous solution and a chromium sulfate aqueous solution were simultaneously added to pure water adjusted to 20 ° C. The addition rate was 8.3 g / min for the sodium carbonate aqueous solution and 2.9 g / min for the chromium sulfate aqueous solution. Molar ratio of CO 3 for Cr at this time (CO 3 / Cr) was 2.08. The addition was continuously performed for 60 minutes. During the addition, the pH of the reaction solution was maintained at about 7. Moreover, the temperature of the reaction liquid was maintained between 20-30 degreeC during addition. During the addition, the reaction solution was stirred (350 rpm) so that the amount of chromium sulfate was not locally excessive with respect to the amount of sodium carbonate. The precipitate formed by the reaction was washed with filtered water at 30 ° C. until the filtrate had a conductivity of 1 mS / cm to obtain a chromium (III) carbonate cake. The chromium (III) carbonate cake was vacuum dried at 70 ° C. for 12 hours. The obtained chromium (III) carbonate was measured in the same manner as in the examples. The results are shown in Table 2.
［比較例２］
１０％炭酸ナトリウム水溶液５００ｇと、３５％塩化クロム水溶液（日本化学工業株式会社製）８３．９ｇをそれぞれ容器に入れ準備した。次に１０％炭酸ナトリウム水溶液を２０℃に調整し、また３５％塩化クロム水溶液を純水で希釈して２５％塩化クロム水溶液とし、これを２０℃に調整した。２０℃に調整した純水中に、炭酸ナトリウム水溶液と塩化クロム水溶液を同時添加した。添加速度は、炭酸ナトリウム水溶液が８．３ｇ／分、硫酸クロム水溶液が２．０ｇ／分であった。このときのＣｒに対するＣＯ３の仕込モル比（ＣＯ３／Ｃｒ）は２．５であった。添加は連続的に６０分間行った。添加の間、反応液のｐＨは約７に維持されていた。また、添加の間、反応液の温度は２０〜３０℃の間に維持されていた。また、添加の間、反応液を攪拌（３５０ｒｐｍ）して、炭酸ナトリウムの量に対して三価のクロムの量が局所的に過剰にならないようにした。反応によって生成した沈殿を、濾液の導電率が１ｍＳ／ｃｍになるまで３０℃で濾過水洗し、炭酸クロム(III)ケーキを得た。この炭酸クロム(III)ケーキを、７０℃で１２時間にわたり真空乾燥させた。得られた炭酸クロム(III)について実施例と同様の測定を行った。その結果を表２に示す。
[Comparative Example 2]
A 10% sodium carbonate aqueous solution (500 g) and a 35% chromium chloride aqueous solution (manufactured by Nippon Chemical Industry Co., Ltd.) (83.9 g) were prepared in respective containers. Next, a 10% sodium carbonate aqueous solution was adjusted to 20 ° C, and a 35% chromium chloride aqueous solution was diluted with pure water to obtain a 25% chromium chloride aqueous solution, which was adjusted to 20 ° C. A sodium carbonate aqueous solution and a chromium chloride aqueous solution were simultaneously added to pure water adjusted to 20 ° C. The addition rate was 8.3 g / min for an aqueous sodium carbonate solution and 2.0 g / min for an aqueous chromium sulfate solution. Molar ratio of CO 3 for Cr at this time (CO 3 / Cr) was 2.5. The addition was continuously performed for 60 minutes. During the addition, the pH of the reaction solution was maintained at about 7. Moreover, the temperature of the reaction liquid was maintained between 20-30 degreeC during addition. During the addition, the reaction solution was stirred (350 rpm) so that the amount of trivalent chromium was not locally excessive with respect to the amount of sodium carbonate. The precipitate formed by the reaction was washed with filtered water at 30 ° C. until the filtrate had a conductivity of 1 mS / cm to obtain a chromium (III) carbonate cake. The chromium (III) carbonate cake was vacuum dried at 70 ° C. for 12 hours. The obtained chromium (III) carbonate was measured in the same manner as in the example. The results are shown in Table 2.
［比較例３］
炭酸クロム（III）ケーキを、７０℃で１８時間にわたり真空乾燥させたこと以外は、実施例１と同じ方法で行った。このときのＣｒに対するＣＯ３の仕込モル比（ＣＯ３／Ｃｒ）は１．５６であった。得られた炭酸クロム(III)について、実施例１と同様の測定を行った。その結果を表２に示す。
[Comparative Example 3]
The same procedure as in Example 1 was followed, except that the chromium (III) carbonate cake was vacuum dried at 70 ° C. for 18 hours. Molar ratio of CO 3 for Cr at this time (CO 3 / Cr) was 1.56. The obtained chromium (III) carbonate was measured in the same manner as in Example 1. The results are shown in Table 2.
以上の実施例及び比較例の結果から、実施例の炭酸クロム(III)（本発明品）は、フッ酸に対する溶解性が高いことが判る。これに対して、本発明の諸条件を満たさない比較例の炭酸クロム(III)は、フッ酸に対して完全に溶解しないことが判る。 From the results of the above examples and comparative examples, it can be seen that the chromium (III) carbonate of the example (product of the present invention) has high solubility in hydrofluoric acid. On the other hand, it can be seen that the chromium (III) carbonate of the comparative example that does not satisfy the various conditions of the present invention does not completely dissolve in hydrofluoric acid.
［実施例４］
実施例１と同様にして炭酸クロム(III)粉末を得た。次いで、得られた炭酸クロム(III)粉末を、温度２５℃で各種の無機酸水溶液１リットルに、又は温度５０℃で有機酸水溶液１リットルに、Ｃｒとして１ｇ含有に相当する量添加し溶解させて、無機酸クロム水溶液又は有機酸クロム水溶液をそれぞれ得た。溶解に要した時間（単位：分）を以下の表３に示す。
[Example 4]
In the same manner as in Example 1, chromium (III) carbonate powder was obtained. Next, the obtained chromium (III) carbonate powder is added to 1 liter of various inorganic acid aqueous solutions at a temperature of 25 ° C. or dissolved in 1 liter of an organic acid aqueous solution at a temperature of 50 ° C. in an amount corresponding to 1 g as Cr. Thus, an inorganic acid chromium aqueous solution or an organic acid chromium aqueous solution was obtained. The time (unit: minutes) required for dissolution is shown in Table 3 below.
［実施例５〜７］
実施例１と同様にして炭酸クロム(III)粉末を得た。次いで、温度２５℃で２種の酸を含む水溶液１リットルに、Ｃｒとして１ｇ含有に相当する量添加し溶解させて、クロム(III)源を含む水溶液をそれぞれ得た。溶解に要した時間（単位：分）を以下の表４に示す。
なお、各実施例で使用した酸水溶液の組成は以下のとおりである。
Ａ液（ｐＨ０．２）；塩酸２．６重量％、硝酸５．２重量％
Ｂ液（ｐＨ０．４）；硫酸２．５重量％、リン酸３．３重量％
Ｃ液（ｐＨ０．３）；塩酸２．６重量％、シュウ酸２．２重量％
[Examples 5 to 7]
In the same manner as in Example 1, chromium (III) carbonate powder was obtained. Next, an amount corresponding to 1 g of Cr was added to 1 liter of an aqueous solution containing two acids at a temperature of 25 ° C. and dissolved to obtain aqueous solutions containing a chromium (III) source. The time (unit: minute) required for dissolution is shown in Table 4 below.
In addition, the composition of the acid aqueous solution used in each Example is as follows.
Liquid A (pH 0.2): 2.6% by weight of hydrochloric acid, 5.2% by weight of nitric acid
Liquid B (pH 0.4); sulfuric acid 2.5% by weight, phosphoric acid 3.3% by weight
Liquid C (pH 0.3); hydrochloric acid 2.6% by weight, oxalic acid 2.2% by weight
［使用例１］
内容積８リットルの角型めっき槽に、以下の組成を有する三価クロムめっき用めっき液を調製した。被めっき物として軟鋼丸棒を用い、また陽極として炭素板を用い、浴温５０℃、電流密度４０Ａ／ｄｍ2の条件でクロムめっきを行った。丸棒のめっき前後の質量測定から消費クロム量及び浴のクロム濃度を算出し、めっき液中のクロム濃度が１〜２ｇ／リットル低下したら、実施例１で得られた炭酸クロム(III)のスラリーを、電析した金属クロムに相当する分だけめっき液に添加し、充分に攪拌しながらクロムめっきを継続して行った。その結果、良好なクロムめっきが得られた。
[Usage example 1]
A plating solution for trivalent chromium plating having the following composition was prepared in a square plating tank having an internal volume of 8 liters. A mild steel round bar was used as an object to be plated, a carbon plate was used as an anode, and chromium plating was performed under conditions of a bath temperature of 50 ° C. and a current density of 40 A / dm 2 . Chromium (III) carbonate slurry obtained in Example 1 when the amount of chromium consumed and the chromium concentration in the bath were calculated from the mass measurement before and after plating the round bar, and the chromium concentration in the plating solution decreased by 1 to 2 g / liter. Was added to the plating solution in an amount corresponding to the electrodeposited metal chromium, and chromium plating was continued with sufficient stirring. As a result, good chromium plating was obtained.
（めっき液の組成）
塩化クロム６水和物 ３００ｇ／Ｌ
ホウ酸 ３０ｇ／Ｌ
グリシン ５０ｇ／Ｌ
塩化アンモニウム １３０ｇ／Ｌ
塩化アルミニウム６水和物 ５０ｇ／Ｌ
(Composition of plating solution)
Chromium chloride hexahydrate 300g / L
Boric acid 30g / L
Glycine 50g / L
Ammonium chloride 130g / L
Aluminum chloride hexahydrate 50g / L
Claims (7)
三価のクロムを含む水溶液中のＣｒに対する炭酸塩水溶液中のＣＯ３のモル比（ＣＯ３／Ｃｒ）が０．５〜２．０であり、反応液のｐＨが６以下であり、反応液温が０℃以上５０℃未満の条件下で、炭酸塩水溶液と三価のクロムを含む水溶液とを、水性媒体へ同時に添加して炭酸クロム(III)を生成させる第一工程、
第一工程で得られた炭酸クロム(III)を濾過後、濾液の導電率が５ｍＳ／ｃｍ以下となるまで水洗してケーキを得る第二工程、及び
第二工程で得られたケーキを、１１０℃で２時間乾燥したときの乾燥減量が２０質量％以上となるように乾燥して炭酸クロム(III)を得る第三工程、を有することを特徴とする炭酸クロム(III)の製造方法。 A method for producing chromium (III) carbonate according to claim 1,
The molar ratio of CO 3 in the carbonate aqueous solution (CO 3 / Cr) to Cr in the aqueous solution containing trivalent chromium is 0.5 to 2.0, the pH of the reaction solution is 6 or less, and the reaction solution A first step in which an aqueous carbonate solution and an aqueous solution containing trivalent chromium are simultaneously added to an aqueous medium under the conditions of a temperature of 0 ° C. or higher and lower than 50 ° C. to produce chromium (III) carbonate;
After filtering the chromium (III) carbonate obtained in the first step, the second step to obtain a cake by washing with water until the conductivity of the filtrate is 5 mS / cm or less, and the cake obtained in the second step are 110 A method for producing chromium (III) carbonate, comprising a third step of obtaining chromium carbonate (III) by drying such that the weight loss after drying for 2 hours at 20 ° C. is 20% by mass or more.
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