JP5179095B2 - Method for producing high-purity aluminum hydroxide and high-purity aluminum hydroxide obtained by the method - Google Patents
Method for producing high-purity aluminum hydroxide and high-purity aluminum hydroxide obtained by the method Download PDFInfo
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- JP5179095B2 JP5179095B2 JP2007149559A JP2007149559A JP5179095B2 JP 5179095 B2 JP5179095 B2 JP 5179095B2 JP 2007149559 A JP2007149559 A JP 2007149559A JP 2007149559 A JP2007149559 A JP 2007149559A JP 5179095 B2 JP5179095 B2 JP 5179095B2
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- aluminum hydroxide
- aqueous solution
- sodium aluminate
- purity aluminum
- purity
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- WNROFYMDJYEPJX-UHFFFAOYSA-K aluminium hydroxide Chemical compound [OH-].[OH-].[OH-].[Al+3] WNROFYMDJYEPJX-UHFFFAOYSA-K 0.000 title claims description 177
- 238000000034 method Methods 0.000 title claims description 21
- 238000004519 manufacturing process Methods 0.000 title claims description 18
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims description 73
- ANBBXQWFNXMHLD-UHFFFAOYSA-N aluminum;sodium;oxygen(2-) Chemical compound [O-2].[O-2].[Na+].[Al+3] ANBBXQWFNXMHLD-UHFFFAOYSA-N 0.000 claims description 69
- 229910001388 sodium aluminate Inorganic materials 0.000 claims description 64
- 239000007864 aqueous solution Substances 0.000 claims description 58
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 claims description 44
- 239000012535 impurity Substances 0.000 claims description 44
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 41
- 239000002245 particle Substances 0.000 claims description 36
- 239000013078 crystal Substances 0.000 claims description 33
- 239000002738 chelating agent Substances 0.000 claims description 29
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 claims description 27
- 229910052742 iron Inorganic materials 0.000 claims description 26
- 239000000243 solution Substances 0.000 claims description 26
- 239000001569 carbon dioxide Substances 0.000 claims description 22
- 229910002092 carbon dioxide Inorganic materials 0.000 claims description 22
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 17
- 229910052799 carbon Inorganic materials 0.000 claims description 15
- 239000007789 gas Substances 0.000 claims description 12
- 229910052751 metal Inorganic materials 0.000 claims description 12
- 239000007800 oxidant agent Substances 0.000 claims description 10
- 238000005406 washing Methods 0.000 claims description 10
- 239000002184 metal Substances 0.000 claims description 9
- 150000003839 salts Chemical class 0.000 claims description 9
- 239000000126 substance Substances 0.000 claims description 9
- KCXVZYZYPLLWCC-UHFFFAOYSA-N EDTA Chemical compound OC(=O)CN(CC(O)=O)CCN(CC(O)=O)CC(O)=O KCXVZYZYPLLWCC-UHFFFAOYSA-N 0.000 claims description 8
- MHAJPDPJQMAIIY-UHFFFAOYSA-N Hydrogen peroxide Chemical compound OO MHAJPDPJQMAIIY-UHFFFAOYSA-N 0.000 claims description 6
- 239000002253 acid Substances 0.000 claims description 6
- 238000007664 blowing Methods 0.000 claims description 5
- 150000001875 compounds Chemical class 0.000 claims description 5
- TWNQGVIAIRXVLR-UHFFFAOYSA-N oxo(oxoalumanyloxy)alumane Chemical compound O=[Al]O[Al]=O TWNQGVIAIRXVLR-UHFFFAOYSA-N 0.000 claims description 5
- QBWCMBCROVPCKQ-UHFFFAOYSA-N chlorous acid Chemical compound OCl=O QBWCMBCROVPCKQ-UHFFFAOYSA-N 0.000 claims description 4
- 229940077239 chlorous acid Drugs 0.000 claims description 4
- QWPPOHNGKGFGJK-UHFFFAOYSA-N hypochlorous acid Chemical compound ClO QWPPOHNGKGFGJK-UHFFFAOYSA-N 0.000 claims description 4
- 239000005416 organic matter Substances 0.000 claims description 4
- 239000012498 ultrapure water Substances 0.000 claims description 2
- 239000011734 sodium Substances 0.000 description 16
- 238000001914 filtration Methods 0.000 description 10
- 238000006243 chemical reaction Methods 0.000 description 9
- 229910018072 Al 2 O 3 Inorganic materials 0.000 description 8
- 239000012776 electronic material Substances 0.000 description 8
- 238000006386 neutralization reaction Methods 0.000 description 8
- 235000011121 sodium hydroxide Nutrition 0.000 description 8
- YDONNITUKPKTIG-UHFFFAOYSA-N [Nitrilotris(methylene)]trisphosphonic acid Chemical compound OP(O)(=O)CN(CP(O)(O)=O)CP(O)(O)=O YDONNITUKPKTIG-UHFFFAOYSA-N 0.000 description 7
- 229910052782 aluminium Inorganic materials 0.000 description 7
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 7
- 230000007062 hydrolysis Effects 0.000 description 7
- 238000006460 hydrolysis reaction Methods 0.000 description 7
- 239000011164 primary particle Substances 0.000 description 7
- 239000002994 raw material Substances 0.000 description 7
- 230000003287 optical effect Effects 0.000 description 6
- 238000001556 precipitation Methods 0.000 description 6
- 229910052708 sodium Inorganic materials 0.000 description 6
- URDCARMUOSMFFI-UHFFFAOYSA-N 2-[2-[bis(carboxymethyl)amino]ethyl-(2-hydroxyethyl)amino]acetic acid Chemical compound OCCN(CC(O)=O)CCN(CC(O)=O)CC(O)=O URDCARMUOSMFFI-UHFFFAOYSA-N 0.000 description 5
- 230000000052 comparative effect Effects 0.000 description 5
- NWUYHJFMYQTDRP-UHFFFAOYSA-N 1,2-bis(ethenyl)benzene;1-ethenyl-2-ethylbenzene;styrene Chemical compound C=CC1=CC=CC=C1.CCC1=CC=CC=C1C=C.C=CC1=CC=CC=C1C=C NWUYHJFMYQTDRP-UHFFFAOYSA-N 0.000 description 4
- QPCDCPDFJACHGM-UHFFFAOYSA-N N,N-bis{2-[bis(carboxymethyl)amino]ethyl}glycine Chemical compound OC(=O)CN(CC(O)=O)CCN(CC(=O)O)CCN(CC(O)=O)CC(O)=O QPCDCPDFJACHGM-UHFFFAOYSA-N 0.000 description 4
- 238000004458 analytical method Methods 0.000 description 4
- 238000004140 cleaning Methods 0.000 description 4
- 230000007423 decrease Effects 0.000 description 4
- 239000002305 electric material Substances 0.000 description 4
- 239000003456 ion exchange resin Substances 0.000 description 4
- 229920003303 ion-exchange polymer Polymers 0.000 description 4
- 239000012528 membrane Substances 0.000 description 4
- 239000000203 mixture Substances 0.000 description 4
- 239000000460 chlorine Substances 0.000 description 3
- 238000010438 heat treatment Methods 0.000 description 3
- 238000005259 measurement Methods 0.000 description 3
- 150000004706 metal oxides Chemical class 0.000 description 3
- 229960003330 pentetic acid Drugs 0.000 description 3
- 230000001376 precipitating effect Effects 0.000 description 3
- 238000003756 stirring Methods 0.000 description 3
- 238000000108 ultra-filtration Methods 0.000 description 3
- DMQQXDPCRUGSQB-UHFFFAOYSA-N 2-[3-[bis(carboxymethyl)amino]propyl-(carboxymethyl)amino]acetic acid Chemical compound OC(=O)CN(CC(O)=O)CCCN(CC(O)=O)CC(O)=O DMQQXDPCRUGSQB-UHFFFAOYSA-N 0.000 description 2
- DGAQECJNVWCQMB-PUAWFVPOSA-M Ilexoside XXIX Chemical compound C[C@@H]1CC[C@@]2(CC[C@@]3(C(=CC[C@H]4[C@]3(CC[C@@H]5[C@@]4(CC[C@@H](C5(C)C)OS(=O)(=O)[O-])C)C)[C@@H]2[C@]1(C)O)C)C(=O)O[C@H]6[C@@H]([C@H]([C@@H]([C@H](O6)CO)O)O)O.[Na+] DGAQECJNVWCQMB-PUAWFVPOSA-M 0.000 description 2
- JYXGIOKAKDAARW-UHFFFAOYSA-N N-(2-hydroxyethyl)iminodiacetic acid Chemical compound OCCN(CC(O)=O)CC(O)=O JYXGIOKAKDAARW-UHFFFAOYSA-N 0.000 description 2
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 description 2
- NBIIXXVUZAFLBC-UHFFFAOYSA-N Phosphoric acid Chemical compound OP(O)(O)=O NBIIXXVUZAFLBC-UHFFFAOYSA-N 0.000 description 2
- 238000010521 absorption reaction Methods 0.000 description 2
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 2
- 229910052791 calcium Inorganic materials 0.000 description 2
- 229910052801 chlorine Inorganic materials 0.000 description 2
- 238000000151 deposition Methods 0.000 description 2
- WJJMNDUMQPNECX-UHFFFAOYSA-N dipicolinic acid Chemical compound OC(=O)C1=CC=CC(C(O)=O)=N1 WJJMNDUMQPNECX-UHFFFAOYSA-N 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 150000002506 iron compounds Chemical class 0.000 description 2
- 238000002356 laser light scattering Methods 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 229910044991 metal oxide Inorganic materials 0.000 description 2
- 230000003472 neutralizing effect Effects 0.000 description 2
- 229910017604 nitric acid Inorganic materials 0.000 description 2
- 239000005304 optical glass Substances 0.000 description 2
- 230000001590 oxidative effect Effects 0.000 description 2
- 230000000704 physical effect Effects 0.000 description 2
- 239000000843 powder Substances 0.000 description 2
- 238000002360 preparation method Methods 0.000 description 2
- 238000001223 reverse osmosis Methods 0.000 description 2
- RAEOEMDZDMCHJA-UHFFFAOYSA-N 2-[2-[bis(carboxymethyl)amino]ethyl-[2-[2-[bis(carboxymethyl)amino]ethyl-(carboxymethyl)amino]ethyl]amino]acetic acid Chemical compound OC(=O)CN(CC(O)=O)CCN(CC(=O)O)CCN(CCN(CC(O)=O)CC(O)=O)CC(O)=O RAEOEMDZDMCHJA-UHFFFAOYSA-N 0.000 description 1
- QGZKDVFQNNGYKY-UHFFFAOYSA-O Ammonium Chemical compound [NH4+] QGZKDVFQNNGYKY-UHFFFAOYSA-O 0.000 description 1
- HLTKLTFTCVCOKY-UHFFFAOYSA-N C(C)(=O)O.C(C)(=O)O.C(C)(=O)O.C(C)(=O)O.C(C)(=O)O.C(C)(=O)O.NCCNCCNCCN.[Na].[Na].[Na].[Na].[Na].[Na] Chemical compound C(C)(=O)O.C(C)(=O)O.C(C)(=O)O.C(C)(=O)O.C(C)(=O)O.C(C)(=O)O.NCCNCCNCCN.[Na].[Na].[Na].[Na].[Na].[Na] HLTKLTFTCVCOKY-UHFFFAOYSA-N 0.000 description 1
- ZAMOUSCENKQFHK-UHFFFAOYSA-N Chlorine atom Chemical compound [Cl] ZAMOUSCENKQFHK-UHFFFAOYSA-N 0.000 description 1
- QXNVGIXVLWOKEQ-UHFFFAOYSA-N Disodium Chemical class [Na][Na] QXNVGIXVLWOKEQ-UHFFFAOYSA-N 0.000 description 1
- 239000003109 Disodium ethylene diamine tetraacetate Substances 0.000 description 1
- ZGTMUACCHSMWAC-UHFFFAOYSA-L EDTA disodium salt (anhydrous) Chemical compound [Na+].[Na+].OC(=O)CN(CC([O-])=O)CCN(CC(O)=O)CC([O-])=O ZGTMUACCHSMWAC-UHFFFAOYSA-L 0.000 description 1
- QZKRHPLGUJDVAR-UHFFFAOYSA-K EDTA trisodium salt Chemical compound [Na+].[Na+].[Na+].OC(=O)CN(CC([O-])=O)CCN(CC([O-])=O)CC([O-])=O QZKRHPLGUJDVAR-UHFFFAOYSA-K 0.000 description 1
- DBVJJBKOTRCVKF-UHFFFAOYSA-N Etidronic acid Chemical compound OP(=O)(O)C(O)(C)P(O)(O)=O DBVJJBKOTRCVKF-UHFFFAOYSA-N 0.000 description 1
- 229910001111 Fine metal Inorganic materials 0.000 description 1
- 102000006835 Lamins Human genes 0.000 description 1
- 108010047294 Lamins Proteins 0.000 description 1
- OHHLQFCWNFSQEY-UHFFFAOYSA-N O.O.O.O.[Na].[Na].[Na].[Na].OC(=O)CN(CC(O)=O)CCN(CC(O)=O)CC(O)=O Chemical compound O.O.O.O.[Na].[Na].[Na].[Na].OC(=O)CN(CC(O)=O)CCN(CC(O)=O)CC(O)=O OHHLQFCWNFSQEY-UHFFFAOYSA-N 0.000 description 1
- IIFGCAJBLSOVSP-UHFFFAOYSA-N OCCN(CC(=O)O)CC(=O)O.[Na].[Na] Chemical compound OCCN(CC(=O)O)CC(=O)O.[Na].[Na] IIFGCAJBLSOVSP-UHFFFAOYSA-N 0.000 description 1
- BUGBHKTXTAQXES-UHFFFAOYSA-N Selenium Chemical compound [Se] BUGBHKTXTAQXES-UHFFFAOYSA-N 0.000 description 1
- 239000005708 Sodium hypochlorite Substances 0.000 description 1
- FWFKWYODLSFYLE-UHFFFAOYSA-J [Na+].[Na+].[Na+].[Na+].CCO.[O-]P(=O)OP([O-])=O.[O-]P(=O)OP([O-])=O Chemical compound [Na+].[Na+].[Na+].[Na+].CCO.[O-]P(=O)OP([O-])=O.[O-]P(=O)OP([O-])=O FWFKWYODLSFYLE-UHFFFAOYSA-J 0.000 description 1
- MVCMTOJZXPCZNM-UHFFFAOYSA-I [Na+].[Na+].[Na+].[Na+].[Na+].CC([O-])=O.CC([O-])=O.CC([O-])=O.CC([O-])=O.CC([O-])=O.NCCNCCN Chemical compound [Na+].[Na+].[Na+].[Na+].[Na+].CC([O-])=O.CC([O-])=O.CC([O-])=O.CC([O-])=O.CC([O-])=O.NCCNCCN MVCMTOJZXPCZNM-UHFFFAOYSA-I 0.000 description 1
- HYNVBUNEESWDMI-UHFFFAOYSA-N [Na].[Na].[Na].OC(CP(O)(=O)O)P(O)(=O)O Chemical compound [Na].[Na].[Na].OC(CP(O)(=O)O)P(O)(=O)O HYNVBUNEESWDMI-UHFFFAOYSA-N 0.000 description 1
- YXVHVBFCVDBUMB-UHFFFAOYSA-N acetic acid 2-[2-[bis(carboxymethyl)amino]ethyl-(carboxymethyl)amino]acetic acid Chemical compound CC(O)=O.CC(O)=O.CC(O)=O.OC(=O)CN(CC(O)=O)CCN(CC(O)=O)CC(O)=O YXVHVBFCVDBUMB-UHFFFAOYSA-N 0.000 description 1
- RUSUZAGBORAKPY-UHFFFAOYSA-N acetic acid;n'-[2-(2-aminoethylamino)ethyl]ethane-1,2-diamine Chemical compound CC(O)=O.CC(O)=O.CC(O)=O.CC(O)=O.CC(O)=O.CC(O)=O.NCCNCCNCCN RUSUZAGBORAKPY-UHFFFAOYSA-N 0.000 description 1
- 230000002378 acidificating effect Effects 0.000 description 1
- 239000003463 adsorbent Substances 0.000 description 1
- 230000032683 aging Effects 0.000 description 1
- 239000012670 alkaline solution Substances 0.000 description 1
- 229910000147 aluminium phosphate Inorganic materials 0.000 description 1
- 150000008064 anhydrides Chemical class 0.000 description 1
- 229910001570 bauxite Inorganic materials 0.000 description 1
- 150000001732 carboxylic acid derivatives Chemical class 0.000 description 1
- 150000004697 chelate complex Chemical class 0.000 description 1
- 239000003153 chemical reaction reagent Substances 0.000 description 1
- 238000005345 coagulation Methods 0.000 description 1
- 230000015271 coagulation Effects 0.000 description 1
- 238000011109 contamination Methods 0.000 description 1
- 150000004696 coordination complex Chemical class 0.000 description 1
- 238000000354 decomposition reaction Methods 0.000 description 1
- KYQODXQIAJFKPH-UHFFFAOYSA-N diazanium;2-[2-[bis(carboxymethyl)amino]ethyl-(carboxylatomethyl)amino]acetate Chemical compound [NH4+].[NH4+].OC(=O)CN(CC([O-])=O)CCN(CC(O)=O)CC([O-])=O KYQODXQIAJFKPH-UHFFFAOYSA-N 0.000 description 1
- QDHHNSIGXVMRCX-UHFFFAOYSA-N diazanium;2-[carboxylatomethyl(2-hydroxyethyl)amino]acetate Chemical compound [NH4+].[NH4+].OCCN(CC([O-])=O)CC([O-])=O QDHHNSIGXVMRCX-UHFFFAOYSA-N 0.000 description 1
- 235000019301 disodium ethylene diamine tetraacetate Nutrition 0.000 description 1
- 238000004090 dissolution Methods 0.000 description 1
- 229960004585 etidronic acid Drugs 0.000 description 1
- ZWAHJGIGWXGTLV-UHFFFAOYSA-N hexaazanium hexaacetate Chemical compound [NH4+].[NH4+].[NH4+].[NH4+].[NH4+].[NH4+].CC([O-])=O.CC([O-])=O.CC([O-])=O.CC([O-])=O.CC([O-])=O.CC([O-])=O ZWAHJGIGWXGTLV-UHFFFAOYSA-N 0.000 description 1
- 150000004677 hydrates Chemical class 0.000 description 1
- 230000003301 hydrolyzing effect Effects 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-M hydroxide Chemical compound [OH-] XLYOFNOQVPJJNP-UHFFFAOYSA-M 0.000 description 1
- 230000033444 hydroxylation Effects 0.000 description 1
- 238000005805 hydroxylation reaction Methods 0.000 description 1
- NBZBKCUXIYYUSX-UHFFFAOYSA-N iminodiacetic acid Chemical group OC(=O)CNCC(O)=O NBZBKCUXIYYUSX-UHFFFAOYSA-N 0.000 description 1
- 239000008235 industrial water Substances 0.000 description 1
- 238000011835 investigation Methods 0.000 description 1
- 210000005053 lamin Anatomy 0.000 description 1
- 239000003446 ligand Substances 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- MGFYIUFZLHCRTH-UHFFFAOYSA-N nitrilotriacetic acid Chemical compound OC(=O)CN(CC(O)=O)CC(O)=O MGFYIUFZLHCRTH-UHFFFAOYSA-N 0.000 description 1
- 229910052700 potassium Inorganic materials 0.000 description 1
- 239000002244 precipitate Substances 0.000 description 1
- 239000000047 product Substances 0.000 description 1
- 238000000746 purification Methods 0.000 description 1
- 229910052711 selenium Inorganic materials 0.000 description 1
- 239000011669 selenium Substances 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
- SUKJFIGYRHOWBL-UHFFFAOYSA-N sodium hypochlorite Chemical compound [Na+].Cl[O-] SUKJFIGYRHOWBL-UHFFFAOYSA-N 0.000 description 1
- KKCBUQHMOMHUOY-UHFFFAOYSA-N sodium oxide Chemical compound [O-2].[Na+].[Na+] KKCBUQHMOMHUOY-UHFFFAOYSA-N 0.000 description 1
- 229910001948 sodium oxide Inorganic materials 0.000 description 1
- 238000001179 sorption measurement Methods 0.000 description 1
- 239000007858 starting material Substances 0.000 description 1
- LESFYQKBUCDEQP-UHFFFAOYSA-N tetraazanium;2-[2-[bis(carboxylatomethyl)amino]ethyl-(carboxylatomethyl)amino]acetate Chemical compound N.N.N.N.OC(=O)CN(CC(O)=O)CCN(CC(O)=O)CC(O)=O LESFYQKBUCDEQP-UHFFFAOYSA-N 0.000 description 1
- UEUXEKPTXMALOB-UHFFFAOYSA-J tetrasodium;2-[2-[bis(carboxylatomethyl)amino]ethyl-(carboxylatomethyl)amino]acetate Chemical compound [Na+].[Na+].[Na+].[Na+].[O-]C(=O)CN(CC([O-])=O)CCN(CC([O-])=O)CC([O-])=O UEUXEKPTXMALOB-UHFFFAOYSA-J 0.000 description 1
- HRXKRNGNAMMEHJ-UHFFFAOYSA-K trisodium citrate Chemical compound [Na+].[Na+].[Na+].[O-]C(=O)CC(O)(CC([O-])=O)C([O-])=O HRXKRNGNAMMEHJ-UHFFFAOYSA-K 0.000 description 1
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- Compounds Of Alkaline-Earth Elements, Aluminum Or Rare-Earth Metals (AREA)
Description
本発明は、高性能光学レンズ等の製造原料として、あるいは、電気・電子材料として有用な高純度の水酸化アルミニウム及びその製造方法に関する。 The present invention relates to high-purity aluminum hydroxide useful as a raw material for producing high-performance optical lenses or the like, or as an electric / electronic material, and a method for producing the same.
近年、光学レンズや電気、電子材料の高機能化、高性能化に伴い、原料となる水酸化アルミニウムに対する高い品質が求められている。
水酸化アルミニウムは一般的にバイヤー法により製造されているものの、バイヤー法によって製造された水酸化アルミニウムは、多量の有機物や鉄化合物等を不純物として含んでいる。これら不純物は光学レンズや電気、電子材料の性能を低下させる原因となるため、従来から有機物や鉄化合物などの不純物除去方法が提案されている。
In recent years, high quality and high performance of aluminum hydroxide as a raw material has been demanded as optical lenses, electrical and electronic materials have higher functionality and higher performance.
Although aluminum hydroxide is generally manufactured by the Bayer method, the aluminum hydroxide manufactured by the Bayer method contains a large amount of organic substances, iron compounds, and the like as impurities. Since these impurities cause the performance of optical lenses, electrical and electronic materials to deteriorate, methods for removing impurities such as organic substances and iron compounds have been proposed.
例えば、特許文献１には、過飽和アルミン酸ナトリウム溶液に所定の性状を有する種結晶水酸化アルミニウムを添加して少量の水酸化アルミニウムを析出させ、この水酸化アルミニウムを析出させる際に過飽和アルミン酸ナトリウム溶液中のＦｅを始めとするＣａ、Ｍｇ、Ｔｉ等の金属の酸化物、水和物、塩等の不純物を吸着せしめてこの水酸化アルミニウムと共に除去し、次いで再び所定の性状を有する種結晶水酸化アルミニウムを添加して水酸化アルミニウムを析出させることにより、高純度の水酸化アルミニウムを製造することが記載されている。しかしながら、この方法では種結晶として添加する水酸化アルミニウムとして少なくとも８ｍ2／ｇのＢＥＴ比表面積を有する粉砕状水酸化アルミニウムを用いる必要があり、得られた水酸化アルミニウム中の鉄不純物も１７５ｐｐｍ存在していることから、性能的に十分ではない。 For example, in Patent Document 1, seed crystal aluminum hydroxide having a predetermined property is added to a supersaturated sodium aluminate solution to precipitate a small amount of aluminum hydroxide, and when this aluminum hydroxide is precipitated, supersaturated sodium aluminate Impurities such as Fe, Ca, Mg, Ti and other metal oxides, hydrates, salts and other impurities are adsorbed and removed together with the aluminum hydroxide, and then seed water having a predetermined property again. It describes that high purity aluminum hydroxide is produced by adding aluminum oxide to precipitate aluminum hydroxide. However, in this method, it is necessary to use ground aluminum hydroxide having a BET specific surface area of at least 8 m 2 / g as aluminum hydroxide to be added as seed crystals, and 175 ppm of iron impurities are also present in the obtained aluminum hydroxide. Therefore, performance is not enough.
また、特許文献２には、溶解Ｎａ2Ｏ濃度１００ｇ／リットル以上及び液中Ｆｅ濃度０．４ｍｇ／リットル以下であって、溶解Ｎａ2Ｏ分と溶解Ａｌ2Ｏ3分とのモル比（Ｍ、溶解Ｎａ2Ｏ分／溶解Ａｌ2Ｏ3分）が１．６〜２．０である過飽和アルミン酸ナトリウム溶液を原料溶液として用い、平均粒子径が１５〜４０μｍであって、全Ｎａ2Ｏ分が０．１質量％以下であり、且つＦｅ分が４ｐｐｍ以下の高純度水酸化アルミニウムを得る方法が記載されている。しかしながらこの方法によって得られる平均粒子径１０μｍ以上の水酸化アルミニウム中の鉄不純物は２ｐｐｍ以上であり、高性能光学レンズ等の製造原料として、あるいは、電気・電子材料用としても好適に使用できるようにするため、さらなる高純度化が求められている。 Patent Document 2 discloses that the dissolved Na 2 O concentration is 100 g / liter or more and the Fe concentration in the solution is 0.4 mg / liter or less, and the molar ratio of dissolved Na 2 O component to dissolved Al 2 O 3 component (M A supersaturated sodium aluminate solution having a dissolved Na 2 O content / dissolved Al 2 O 3 minute) of 1.6 to 2.0 as a raw material solution, an average particle size of 15 to 40 μm, and a total Na 2 O content of A method for obtaining high-purity aluminum hydroxide having a content of 0.1% by mass or less and an Fe content of 4 ppm or less is described. However, the iron impurity in aluminum hydroxide having an average particle diameter of 10 μm or more obtained by this method is 2 ppm or more, so that it can be suitably used as a raw material for producing high-performance optical lenses or for electric / electronic materials. Therefore, further purification is required.
従って、本発明は、高性能光学レンズ又は電気・電子材料として好適な高純度水酸化アルミニウムの製造方法を提供することを目的とする。 Accordingly, an object of the present invention is to provide a method for producing high-purity aluminum hydroxide suitable as a high-performance optical lens or an electric / electronic material.
かかる実情において、本発明者らは鋭意検討を行った結果、バイヤー法等によって得られた水酸化アルミニウムから、粗製アルミン酸ナトリウム水溶液を調製したものであっても特定の工程を順次行うことにより、高性能光学レンズ又は電気・電子材料用として好適な高純度水酸化アルミニウムが製造可能であることを知見し、本発明を完成するに至った。 In such a situation, as a result of intensive investigations, the present inventors, from aluminum hydroxide obtained by the Bayer method and the like, even by preparing a crude sodium aluminate aqueous solution, by sequentially performing specific steps, The inventors have found that high-purity aluminum hydroxide suitable for high-performance optical lenses or electrical / electronic materials can be produced, and have completed the present invention.
すなわち、本発明は、粗製アルミン酸ナトリウム水溶液に酸化剤を作用させて有機物を分解する第１工程、該有機物が分解されたアルミン酸ナトリウム水溶液に種結晶水酸化アルミニウムと水とを添加し、水酸化アルミニウムを析出させ、析出した水酸化アルミニウムを該水酸化アルミニウムに付着した不純物とともに該アルミン酸ナトリウム水溶液から分離除去する第２工程、及び該不純物が除去されたアルミン酸ナトリウム水溶液にキレート剤を添加した後、炭酸ガスを吹き込み、高純度水酸化アルミニウムを析出させる第３工程をこの順に行うことを特徴とする高純度水酸化アルミニウムの製造方法である。
また、前記第３工程は、析出した高純度水酸化アルミニウムをキレート剤を含有する水溶液で洗浄する工程を更に含むことが好ましい。
また、前記第３工程は、種結晶水酸化アルミニウムの存在下に炭酸ガスを吹き込むことが好ましい。
また、前記粗製アルミン酸ナトリウム水溶液は、鉄の含有量が金属換算で１０ｐｐｍ以上で炭素分（ＴＯＣ）の含有量が２００ｐｐｍ以上である粗製水酸化アルミニウムを水酸化ナトリウム水溶液に溶解して調製されたものであることが好ましい。
前記酸化剤は、亜塩素酸、次亜塩素酸及び過酸化水素から選ばれる１以上の化合物であることが好ましい。また、前記キレート剤は、エチレンジアミン四酢酸及びその塩ならびにニトリロトリスメチレンホスホン酸及びその塩から選ばれる１以上の化合物であることも好ましい。
また、前記種結晶水酸化アルミニウムは、平均粒子径が２μｍ以下であることが好ましい。
また、本発明は、前記の方法によって得られ、鉄の含有量が金属換算で２ｐｐｍ以下で、炭素分（ＴＯＣ）の含有量が１００ｐｐｍ以下であり、且つ平均粒子径が１０〜１００μｍである高純度水酸化アルミニウムである。
That is, the present invention provides a first step of decomposing an organic substance by allowing an oxidizing agent to act on a crude sodium aluminate aqueous solution, adding seed crystal aluminum hydroxide and water to the sodium aluminate aqueous solution in which the organic substance has been decomposed, A second step of precipitating aluminum oxide, separating and removing the precipitated aluminum hydroxide together with impurities adhering to the aluminum hydroxide from the sodium aluminate aqueous solution, and adding a chelating agent to the sodium aluminate aqueous solution from which the impurities have been removed Then, the third step of blowing carbon dioxide and depositing high-purity aluminum hydroxide is performed in this order. This is a method for producing high-purity aluminum hydroxide.
The third step preferably further includes a step of washing the precipitated high-purity aluminum hydroxide with an aqueous solution containing a chelating agent.
In the third step, carbon dioxide gas is preferably blown in the presence of seed crystal aluminum hydroxide.
The crude sodium aluminate aqueous solution was prepared by dissolving crude aluminum hydroxide having an iron content of 10 ppm or more in terms of metal and a carbon content (TOC) of 200 ppm or more in an aqueous sodium hydroxide solution. It is preferable.
The oxidizing agent is preferably one or more compounds selected from chlorous acid, hypochlorous acid, and hydrogen peroxide. The chelating agent is also preferably one or more compounds selected from ethylenediaminetetraacetic acid and its salt, and nitrilotrismethylenephosphonic acid and its salt.
The seed crystal aluminum hydroxide preferably has an average particle size of 2 μm or less.
Further, the present invention is obtained by the above method, wherein the iron content is 2 ppm or less in terms of metal, the carbon content (TOC) is 100 ppm or less, and the average particle size is 10 to 100 μm. Purity aluminum hydroxide.
本発明によれば、粗製水酸化アルミニウムを出発原料として用いても、鉄の含有量が２ｐｐｍ以下で、炭素分（ＴＯＣ）の含有量が１００ｐｐｍ以下の高性能光学ガラスや電気・電子材料の製造原料としても好適な高純度水酸化アルミニウムを簡便かつ経済的に得ることができる。
更に、本発明の高純度水酸化アルミニウムの製造方法は、従来の高純度水酸化アルミニウム製造方法と比べ、広い粒子径範囲において低い有機不純物の含有量および低い鉄不純物の含有量を達成することができる。
According to the present invention, even when crude aluminum hydroxide is used as a starting material, high-performance optical glass or electrical / electronic materials having an iron content of 2 ppm or less and a carbon content (TOC) content of 100 ppm or less are produced. High purity aluminum hydroxide suitable as a raw material can be obtained simply and economically.
Furthermore, the method for producing high-purity aluminum hydroxide according to the present invention can achieve a low content of organic impurities and a low content of iron impurities in a wide particle size range as compared with the conventional high-purity aluminum hydroxide production method. it can.
本発明に係る高純度水酸化アルミニウムの製造方法は、以下の３つの工程：
第１工程；粗製アルミン酸ナトリウム水溶液に酸化剤を作用させて有機物を分解する工程、
第２工程；該有機物を分解したアルミン酸ナトリウム水溶液に種結晶水酸化アルミニウムと水を添加し、水酸化アルミニウムを析出させ、析出した水酸化アルミニウムを該水酸化アルミニウムに付着した不純物と共に分離除去する工程、及び
第３工程；該不純物を除去したアルミン酸ナトリウム溶液にキレート剤を添加した後、炭酸ガスを吹き込み、高純度水酸化アルミニウムを析出させる工程を必須の工程として含むことを特徴とする。
本発明においては、上記工程を第１工程、第２工程、第３工程の順に行うことが本発明の高純度水酸化アルミニウムを得る上で極めて重要であり、その技術的な意義について、以下に説明する。
The method for producing high-purity aluminum hydroxide according to the present invention comprises the following three steps:
1st process; The process which decomposes | disassembles organic substance by making an oxidizing agent act on crude sodium aluminate aqueous solution,
Second step: Seed aluminum hydroxide and water are added to the sodium aluminate aqueous solution in which the organic matter is decomposed to precipitate aluminum hydroxide, and the precipitated aluminum hydroxide is separated and removed together with impurities adhering to the aluminum hydroxide. Step and third step: A step of adding a chelating agent to the sodium aluminate solution from which the impurities have been removed and then blowing carbon dioxide to precipitate high-purity aluminum hydroxide is included as an essential step.
In the present invention, performing the above steps in the order of the first step, the second step, and the third step is extremely important in obtaining the high-purity aluminum hydroxide of the present invention. explain.
｛第１工程｝
第１工程は、有機不純物および鉄をはじめとする無機不純物を含有する粗製アルミン酸ナトリウム水溶液中の有機不純物を酸化剤によりＣＯ2やＨ2Ｏ等まで酸化分解する工程である。
本発明において粗製アルミン酸ナトリウム水溶液とは、アルミン酸ナトリウムをＡｌ2Ｏ3基準で少なくとも２０重量％含む水溶液であって、鉄の含有量が金属換算で４ｐｐｍ以上、炭素分（ＴＯＣ）の含有量が５０ｐｐｍ以上のアルミン酸ナトリウム水溶液を示す。
この粗製アルミン酸ナトリウム水溶液はボーキサイト等のアルミナ含有鉱石をカセイソーダ溶液中で加熱することにより、鉱石中のアルミナ分をアルミン酸ナトリウムとしてアルカリ液中に抽出して得られるものや、水酸化アルミニウムと水酸化ナトリウムを使用して得られる粗製アルミン酸ナトリウム水溶液を使用することもできる。
{First step}
The first step is a step of oxidizing and decomposing organic impurities in a crude aqueous sodium aluminate solution containing organic impurities and inorganic impurities such as iron to CO 2 , H 2 O, and the like with an oxidizing agent.
In the present invention, the crude sodium aluminate aqueous solution is an aqueous solution containing at least 20% by weight of sodium aluminate based on Al 2 O 3 , and the iron content is 4 ppm or more in terms of metal and the carbon content (TOC) content. Represents 50 ppm or more of sodium aluminate aqueous solution.
This crude sodium aluminate aqueous solution is obtained by heating an alumina-containing ore such as bauxite in a caustic soda solution to extract the alumina content in the ore as sodium aluminate into an alkaline solution, or aluminum hydroxide and water. A crude sodium aluminate aqueous solution obtained using sodium oxide can also be used.
本発明において、前記粗製アルミン酸ナトリウム水溶液は、バイヤー法によって得られた水酸化アルミニウム（以下粗製水酸化アルミニウムと記す）を水酸化ナトリウム水溶液に溶解して調製されたものを使用することが、除去すべき不純物が少なく、より高純度の水酸化アルミニウムを得られるという観点から特に好ましい。この場合、使用することができる粗製水酸化アルミニウムとしては、市販の工業用グレードが使用できる。これらの粗製水酸化アルミニウム中の鉄や炭素分（ＴＯＣ）の含有量は本発明の各工程を順次行うことにより、各不純物を低減できる関係上、特に制限されるものではないが、もっとも、本実施形態の実用面を考えれば、鉄の含有量が１０ｐｐｍ以上で、炭素分（ＴＯＣ）の含有量が２００ｐｐｍ以上のものを使用することがもっとも望ましい。市販の工業用グレードの水酸化アルミニウムとしては、例えば日本軽金属株式会社製水酸化アルミニウムＢ５２、昭和電工株式会社製水酸化アルミニウムＨ−Ｗ等を使用することができる。本発明で使用する水酸化ナトリウムとしては、市販の工業用グレードが使用できる。 In the present invention, the crude sodium aluminate aqueous solution is removed by using a solution prepared by dissolving aluminum hydroxide obtained by the Bayer method (hereinafter referred to as crude aluminum hydroxide) in an aqueous sodium hydroxide solution. This is particularly preferable from the viewpoint that the amount of impurities to be reduced is less and higher-purity aluminum hydroxide can be obtained. In this case, commercially available industrial grades can be used as the crude aluminum hydroxide that can be used. The content of iron and carbon (TOC) in these crude aluminum hydroxides is not particularly limited in terms of reducing each impurity by sequentially performing each step of the present invention. Considering the practical aspect of the embodiment, it is most desirable to use a material having an iron content of 10 ppm or more and a carbon content (TOC) content of 200 ppm or more. As commercially available industrial grade aluminum hydroxide, for example, Nippon Light Metal Co., Ltd. aluminum hydroxide B52, Showa Denko Co., Ltd. aluminum hydroxide H-W, etc. can be used. A commercially available industrial grade can be used as sodium hydroxide used in the present invention.
また、水酸化ナトリウム水溶液に粗製水酸化アルミニウムを溶解してアルミン酸ナトリウム水溶液を調製する方法は、特に制限はなく、公知の加熱溶解で行うことができる。
なお、本発明の各工程で使用する水は、少なくとも逆浸透膜、限外濾過膜、イオン交換樹脂等を通過させて、Ｎａ、Ｋ、Ｃａ、Ｃｌ、ＳＯ４等のイオン性不純物を除去した純水を用いることが、溶解させる水に由来する不純物の混入を防止できる点で特に好ましい。
逆浸透膜、限外濾過膜又はイオン交換樹脂に通水される被処理水としては、例えば、工業用水、市水、河川水などの原水を凝集濾過装置及び活性炭等からなる前処理装置で処理し、原水中の懸濁物及び有機物の大半を除去したもの、あるいは、更に、イオン交換樹脂を用いる純水装置で処理されたものなどが用いられる。
Moreover, the method of preparing crude sodium aluminate aqueous solution by dissolving crude aluminum hydroxide in sodium hydroxide aqueous solution is not particularly limited, and can be performed by known heating dissolution.
The water used in each step of the present invention is passed through at least a reverse osmosis membrane, an ultrafiltration membrane, an ion exchange resin and the like to remove ionic impurities such as Na, K, Ca, Cl, and SO 4 . It is particularly preferable to use pure water because it can prevent contamination of impurities derived from water to be dissolved.
As treated water that is passed through a reverse osmosis membrane, an ultrafiltration membrane or an ion exchange resin, for example, raw water such as industrial water, city water, and river water is treated with a pretreatment device made of a coagulation filtration device and activated carbon. In addition, those obtained by removing most of the suspended matter and organic matter in the raw water, or those treated by a pure water apparatus using an ion exchange resin are used.
使用することができる酸化剤としては、例えば亜塩素酸、次亜塩素酸、過酸化水素等が挙げられ、これらの中でも、亜塩素酸、次亜塩素酸が安価かつ取り扱いが簡便である点で特に好ましく用いられる。酸化剤の添加量はＴＯＣのＣ（炭素）の当量に対して１〜３倍当量、好ましくは１．５〜２．５倍当量である。この理由は酸化剤の添加量が１倍当量未満では有機不純物の分解が不十分となる傾向があり、一方、３倍当量を超えると過剰な酸化剤による装置の腐蝕が発生する傾向があるためである。 Examples of the oxidizing agent that can be used include chlorous acid, hypochlorous acid, and hydrogen peroxide. Among these, chlorous acid and hypochlorous acid are inexpensive and easy to handle. Particularly preferably used. The addition amount of the oxidizing agent is 1 to 3 times equivalent, preferably 1.5 to 2.5 times equivalent to the equivalent of C (carbon) of TOC. The reason for this is that if the added amount of the oxidant is less than 1 equivalent, the decomposition of the organic impurities tends to be insufficient. It is.
上記粗製アルミン酸ナトリウム水溶液濃度は、溶解Ｎａ2Ｏ濃度として１．６モル／リットル以上であればよく、溶解Ｎａ2Ｏ分／溶解Ａｌ2Ｏ3分のモル比は１．６〜２．０程度であればよい。この粗製アルミン酸ナトリウム水溶液は９０℃以上の温度で作製し、純水により希釈した後に７５℃以下に冷却したときに水酸化アルミニウムを析出する濃度の過飽和アルミン酸ナトリウム水溶液となるように調製することが望ましい。 The concentration of the crude sodium aluminate aqueous solution may be 1.6 mol / liter or more as the dissolved Na 2 O concentration, and the molar ratio of dissolved Na 2 O component / dissolved Al 2 O 3 component is 1.6 to 2.0. Any degree is acceptable. This crude sodium aluminate aqueous solution is prepared at a temperature of 90 ° C. or higher, and is prepared to be a supersaturated sodium aluminate aqueous solution having a concentration that precipitates aluminum hydroxide when cooled to 75 ° C. or lower after being diluted with pure water. Is desirable.
第１工程での反応操作は、所定量の粗製アルミン酸ナトリウム水溶液に酸化剤を添加して３０〜１２０℃、好ましくは５０〜１００℃で、０．５〜５時間、好ましくは１〜３時間反応を行う。 The reaction operation in the first step is performed by adding an oxidizing agent to a predetermined amount of a crude sodium aluminate aqueous solution at 30 to 120 ° C., preferably 50 to 100 ° C., for 0.5 to 5 hours, preferably 1 to 3 hours. Perform the reaction.
｛第２工程｝
第２工程は、第１工程後に得られた有機物の分解を行ったアルミン酸ナトリウム水溶液中に種結晶水酸化アルミニウムと水を添加し、加水分解によって少量の水酸化アルミニウムを析出させ、当該水酸化アルミニウムを該水酸化アルミニウムに付着した不純物と共に濾過等により分離除去する工程である。
この第２工程において、水酸化アルミニウムと共に析出される一部のＦｅ、Ｔｉ、Ｓｉ等を含む不溶分を除去し、後述する第３工程を効果的に実施して実質的にＦｅ、更にはＣｕ、Ｍｇ、Ｎａ等も含有しない水酸化アルミニウムを得ることができる。
この工程において、析出させる水酸化アルミニウム量を増加させれば、それに伴い除去できるＦｅ等の無機不純物量も増加するが、その分高純度水酸化アルミニウムとして得られる収率が低下する。したがって、析出させる水酸化アルミニウム量は粗製アルミン酸ナトリウム中の全アルミニウム量に対して２〜１７重量％、好ましくは５〜１０重量％とすることが望ましい。
{Second step}
In the second step, seeded aluminum hydroxide and water are added to the aqueous sodium aluminate solution obtained by decomposing the organic matter obtained after the first step, and a small amount of aluminum hydroxide is precipitated by hydrolysis, and the hydroxylation is performed. This is a step of separating and removing aluminum together with impurities adhering to the aluminum hydroxide by filtration or the like.
In this second step, some insoluble components including Fe, Ti, Si and the like precipitated together with aluminum hydroxide are removed, and the third step described later is effectively carried out to substantially reduce Fe and further Cu. , Aluminum hydroxide containing no Mg, Na, etc. can be obtained.
In this step, if the amount of aluminum hydroxide to be precipitated is increased, the amount of inorganic impurities such as Fe that can be removed is increased accordingly, but the yield obtained as high-purity aluminum hydroxide is lowered accordingly. Therefore, the amount of aluminum hydroxide to be precipitated is 2 to 17% by weight, preferably 5 to 10% by weight, based on the total amount of aluminum in the crude sodium aluminate.
使用することができる種結晶水酸化アルミニウムの諸物性等は、例えば特公平３−５１６５４号公報等に記載されているＢＥＴ比表面積８ｍ2／ｇ以上等の諸物性を有するものを使用することができる。また、市販の水酸化アルミニウムを用いることもできる。この種結晶水酸化アルミニウムの添加により、アルミン酸ナトリウム水溶液から水酸化アルミニウムが効率的に析出し、その一方で、析出した水酸化アルミニウムは共に析出される微細なＦｅ等の金属酸化物や水酸化物の吸着剤として効果的に作用するため、濾過等の単純な操作によりＦｅ等の不純物を次の第３工程で完全に除去可能な濃度まで低減させることができる。
また、本発明において、平均粒子径が２μｍ以下、好ましくは０．３〜２μｍの種結晶水酸化アルミニウムを使用することで、Ｆｅ等の金属酸化物の除去効果を更に高めることができる。
Various physical properties and the like of the seed crystal aluminum hydroxide that can be used include those having various physical properties such as a BET specific surface area of 8 m 2 / g or more described in Japanese Patent Publication No. 3-51654. it can. Commercially available aluminum hydroxide can also be used. By the addition of the seed crystal aluminum hydroxide, aluminum hydroxide is efficiently precipitated from the aqueous sodium aluminate solution. On the other hand, the precipitated aluminum hydroxide is precipitated together with fine metal oxides such as Fe and hydroxide. In order to effectively act as an adsorbent for materials, impurities such as Fe can be reduced to a concentration that can be completely removed in the next third step by a simple operation such as filtration.
Moreover, in this invention, the removal effect of metal oxides, such as Fe, can further be heightened by using seed crystal aluminum hydroxide whose average particle diameter is 2 micrometers or less, Preferably 0.3-2 micrometers.
第２工程での反応操作は、前記第１工程終了後の処理液に種結晶水酸化アルミニウムと水とを加え加水分解を行い少量の水酸化アルミニウムを析出させる。
水の添加量は溶解しているアルミニウム（Ａｌ2Ｏ3）濃度が１割から２割低下する量にしてＮａ2Ｏ−Ａｌ2Ｏ3−Ｈ2Ｏ系の加水分解域組成にすることが望ましい。この理由は水の添加量が１割未満では析出する水酸化アルミニウム量が不十分になる傾向があり、一方、２割を超えると析出量が多すぎて第３工程で高純度水酸化アルミニウムとして得られる収率が低下する傾向があるためである。
一方、種結晶水酸化アルミニウムの添加量は粗製アルミン酸ナトリウム中のＡｌ（ＯＨ）3に対して１〜１０重量％、好ましくは３〜７重量％である。この理由は種結晶水酸化アルミニウムの添加量が１重量％未満では種結晶水酸化アルミニウム表面積が小さくなり、無機不純物の除去量が小さくなる傾向があり、一方、１０重量％を超えると不純物を含有し、廃棄される水酸化アルミニウム量が増大するので経済的に不利になるためである。
加水分解温度は８５℃以下、好ましくは６０〜８０℃である。この理由は加水分解温度が８５℃を超えると加水分解が起こらなくなる傾向があるからである。また、加水分解を行う時間は、１〜４時間、好ましくは２〜３時間である。
反応終了後、濾過等の常法の分離手段で析出した水酸化アルミニウムを該水酸化アルミニウムに付着した不純物と共にアルミン酸ナトリウム水溶液から除去する。
In the reaction operation in the second step, seed crystal aluminum hydroxide and water are added to the treatment liquid after the completion of the first step for hydrolysis to precipitate a small amount of aluminum hydroxide.
The amount of water added should be such that the concentration of dissolved aluminum (Al 2 O 3 ) is reduced by 10 to 20% to obtain a Na 2 O—Al 2 O 3 —H 2 O hydrolytic zone composition. desirable. The reason for this is that when the amount of water added is less than 10%, the amount of precipitated aluminum hydroxide tends to be insufficient. On the other hand, when the amount exceeds 20%, the amount of precipitated aluminum is too high, so that high purity aluminum hydroxide is obtained in the third step. This is because the yield obtained tends to decrease.
On the other hand, the addition amount of the seed crystal aluminum hydroxide is 1 to 10% by weight, preferably 3 to 7% by weight, based on Al (OH) 3 in the crude sodium aluminate. The reason for this is that if the amount of seed crystal aluminum hydroxide added is less than 1% by weight, the surface area of the seed crystal aluminum hydroxide tends to be small, and the amount of inorganic impurities removed tends to be small. This is because the amount of discarded aluminum hydroxide increases, which is economically disadvantageous.
The hydrolysis temperature is 85 ° C. or lower, preferably 60 to 80 ° C. This is because when the hydrolysis temperature exceeds 85 ° C., hydrolysis tends not to occur. Moreover, the time which performs a hydrolysis is 1-4 hours, Preferably it is 2-3 hours.
After completion of the reaction, aluminum hydroxide precipitated by a conventional separation means such as filtration is removed from the sodium aluminate aqueous solution together with impurities adhering to the aluminum hydroxide.
｛第３工程｝
第３工程は、第２工程後に得られた不純物の除去を行ったアルミン酸ナトリウム溶液にキレート剤を添加して均一に混合した後、炭酸ガスを吹き込んで高純度水酸化アルミニウムを析出させる工程である。第３工程では、第２工程により完全に分離除去できなかった主としてＦｅ等の金属不純物について、キレート剤の添加によりキレート錯体を形成させる一方で水酸化アルミニウムを高純度品として析出させる。
{Third step}
The third step is a step of adding a chelating agent to the sodium aluminate solution from which impurities obtained after the second step have been removed and mixing them uniformly, and then blowing carbon dioxide to precipitate high-purity aluminum hydroxide. is there. In the third step, a metal complex such as Fe, which could not be completely separated and removed in the second step, is formed by adding a chelating agent to form a chelate complex while precipitating aluminum hydroxide as a high purity product.
第３工程で使用するキレート剤としては、鉄と結合して水溶性の錯体を形成するキレート剤であれば使用できる。キレート剤としては、本発明の効果を損なわない限り、任意のものを用いることができ、カルボン酸のようなものも使用できるが、窒素原子又は燐原子を有するキレート剤であって、金属の多座配位子として金属と結合し、錯体を形成するものが好ましい。より好ましくは、キレート剤としては、分子中にイミノ二酢酸骨格を構造の一部に有する化合物又は水溶性の有機リン酸が好ましい。 As the chelating agent used in the third step, any chelating agent that binds to iron to form a water-soluble complex can be used. Any chelating agent can be used as long as it does not impair the effects of the present invention, and a carboxylic acid or the like can also be used. What bind | bond | couples with a metal as a bidentate ligand and forms a complex is preferable. More preferably, the chelating agent is preferably a compound having an iminodiacetic acid skeleton in the molecule or a water-soluble organic phosphoric acid.
具体的には、例えば、（１）エチレンジアミン四酢酸（ＥＤＴＡ）、（２）ヒドロキシエチルエチレンジアミン三酢酸（ＨＥＤＴＡ）、（３）ジヒドロキシエチルエチレンジアミン二酢酸（ＤＨＥＤＤＡ）、（４）ジエチレントリアミン五酢酸（ＤＴＰＡ）、（５）トリエチレンテトラミン六酢酸（ＴＴＨＡ）、（６）ヒドロキシエチルイミノ二酢酸（ＨＩＭＤＡ）、（７）１，３−プロパンジアミン四酢酸（１，３−ＰＤＴＡ）、（８）ニトリロ三酢酸（ＮＴＡ）、（９）ジピコリン酸、（１０）ニトリロトリメチレンホスホン酸（ＮＴＰ）若しくは（１１）ヒドロキシエタンジホスホン酸、又はこれらの誘導体若しくはこれらの塩が挙げられる。（１）〜（１１）の塩としては、具体的には、例えば、（１ａ）エチレンジアミン四酢酸二ナトリウム、エチレンジアミン四酢酸三ナトリウム、エチレンジアミン四酢酸四ナトリウム、エチレンジアミン四酢酸二アンモニウム、エチレンジアミン四酢酸三アンモニウム、エチレンジアミン四酢酸四アンモニウム、（２ａ）ヒドロキシエチルエチレンジアミン三酢酸三ナトリウム、ヒドロキシエチルエチレンジアミン三酢酸三アンモニウム、（３ａ）ジヒドロキシエチルエチレンジアミン二酢酸二ナトリウム、ジヒドロキシエチルエチレンジアミン二酢酸二アンモニウム、（４ａ）ジエチレントリアミン五酢酸五ナトリウム、ジエチレントリアミン五酢酸五アンモニウム、（５ａ）トリエチレンテトラミン六酢酸六ナトリウム、トリエチレンテトラミン六酢酸六アンモニウム、（６ａ）ヒドロキシエチルイミノ二酢酸二ナトリウム、ヒドロキシエチルイミノ二酢酸二アンモニウム、（１０ａ）ニトリロトリメチレンホスホン酸四ナトリウム、ニトリロトリメチレンホスホン酸五ナトリウム、（１１ａ）ヒドロキシエタンジホスホン酸三ナトリウム、ヒドロキシエタンジホスホン酸四ナトリウム等が挙げられる。また、キレート剤は、結晶水を含むものであっても、無水物であってもよい。また、キレート剤は、１種単独又は２種類以上の併用であってもよく、併用する場合、任意の割合で用いることができる。
本発明で使用されるキレート剤の量は、原料の水酸化アルミニウムやアルミン酸ナトリウム水溶液に含まれる鉄や二価金属のような金属性不純物の量をもとにして決定できるが、使用する水酸化アルミニウムやアルミン酸ナトリウムの種類やロットによるバラツキが大きく、使用量の範囲は特に限定することができない。ただし目安としては金属性不純物の１０〜１００倍当量が適切である。主とするキレート剤の添加は炭酸ガス中和の前に行われるが、中和によって得られた水酸化アルミニウムの濾過・洗浄時の洗浄水にも更に補助的にキレート剤を添加することもできる。このときの使用量はより少量で目安としては金属性不純物の１〜１０倍当量が適切である。
Specifically, for example, (1) ethylenediaminetetraacetic acid (EDTA), (2) hydroxyethylethylenediaminetriacetic acid (HEDTA), (3) dihydroxyethylethylenediaminediacetic acid (DHEDDA), (4) diethylenetriaminepentaacetic acid (DTPA) (5) Triethylenetetramine hexaacetic acid (TTHA), (6) Hydroxyethyliminodiacetic acid (HIMDA), (7) 1,3-propanediaminetetraacetic acid (1,3-PDTA), (8) Nitrilotriacetic acid (NTA), (9) dipicolinic acid, (10) nitrilotrimethylene phosphonic acid (NTP) or (11) hydroxyethane diphosphonic acid, or derivatives or salts thereof. Specific examples of the salts (1) to (11) include (1a) disodium ethylenediaminetetraacetate, trisodium ethylenediaminetetraacetate, tetrasodium ethylenediaminetetraacetate, diammonium ethylenediaminetetraacetate, and ethylenediaminetetraacetic acid triacetate. Ammonium, ethylenediaminetetraacetic acid tetraammonium, (2a) hydroxyethylethylenediaminetriacetic acid trisodium salt, hydroxyethylethylenediaminetriacetic acid triammonium salt, (3a) dihydroxyethylethylenediaminediacetic acid disodium salt, dihydroxyethylethylenediaminediacetic acid diammonium salt, (4a) diethylenetriamine Pentasodium pentaacetate, diethylenetriaminepentaacetic acid pentaammonium, (5a) triethylenetetramine hexaacetic acid hexasodium, triethylenethene Lamin hexaacetate hexaammonium, (6a) hydroxyethyliminodiacetic acid disodium, hydroxyethyliminodiacetic acid diammonium, (10a) nitrilotrimethylenephosphonic acid tetrasodium, nitrilotrimethylenephosphonic acid pentasodium, (11a) hydroxyethanediphosphonic acid Trisodium, tetrasodium hydroxyethane diphosphonate and the like can be mentioned. The chelating agent may contain crystal water or may be an anhydride. In addition, the chelating agent may be used alone or in combination of two or more, and when used in combination, it can be used in any ratio.
The amount of the chelating agent used in the present invention can be determined based on the amount of metallic impurities such as iron and divalent metal contained in the raw material aluminum hydroxide or sodium aluminate aqueous solution. There are large variations depending on the types and lots of aluminum oxide and sodium aluminate, and the range of the amount used cannot be particularly limited. However, as a guide, 10 to 100 times equivalent of metallic impurities is appropriate. The main chelating agent is added before neutralization of carbon dioxide gas, but a chelating agent can also be added to the washing water at the time of filtration and washing of the aluminum hydroxide obtained by neutralization. . The amount used at this time is smaller, and as a guide, 1 to 10 times the equivalent of metallic impurities is appropriate.
次にキレート剤を加えたアルミン酸ナトリウム水溶液に炭酸ガスを吹き込み中和反応を行って高純度水酸化アルミニウムを析出させる。
炭酸ガスはアルミン酸ナトリウム水溶液の液底部に吹き込んで中和を行うことが好ましい。アルミン酸ナトリウム水溶液は強く攪拌していることが好ましく、炭酸ガスはできるだけ細いノズル（噴出口）から吹き込むようにすると炭酸ガスの吸収効率を向上させることができるため好ましい。
炭酸ガスの使用量は、中和の度合いで決められる。すなわち、アルミン酸ナトリウム水溶液のｐＨが７．５〜１１の範囲になるようにすればよい。好ましくはｐＨは８．５〜１１である。この理由はｐＨが７．５より低くなると炭酸ガスの吸収率が低下するため不経済であり、ｐＨが１１より高いと水酸化アルミニウムの析出率が低下して収率が下がるため好ましくない。更に好ましくは、ｐＨは１０．０〜１１である。ｐＨが１０．０より低くなるとＮａ含有量が多くなる傾向がある。
Next, carbon dioxide gas is blown into a sodium aluminate aqueous solution to which a chelating agent is added to carry out a neutralization reaction to precipitate high-purity aluminum hydroxide.
Carbon dioxide gas is preferably neutralized by blowing into the bottom of the aqueous sodium aluminate solution. It is preferable that the sodium aluminate aqueous solution is vigorously stirred. Carbon dioxide gas is preferably blown from a nozzle (jet outlet) that is as thin as possible because the carbon dioxide absorption efficiency can be improved.
The amount of carbon dioxide used is determined by the degree of neutralization. That is, the pH of the sodium aluminate aqueous solution may be in the range of 7.5 to 11. Preferably the pH is 8.5-11. The reason for this is that if the pH is lower than 7.5, the carbon dioxide absorption rate decreases, which is uneconomical. If the pH is higher than 11, the precipitation rate of aluminum hydroxide decreases and the yield decreases, which is not preferable. More preferably, the pH is 10.0-11. When the pH is lower than 10.0, the Na content tends to increase.
炭酸ガスによる中和に先立って、種結晶水酸化アルミニウムの添加を行うこともできる。この場合、種結晶水酸化アルミニウムを加えないで反応を行った場合に比べ、微細な結晶の発生を防止することができるという利点を有する。この際添加する種結晶水酸化アルミニウムとして本発明で得られた高純度水酸化アルミニウムを用いると、種結晶水酸化アルミニウム由来の不純物が低減でき、更に不純物含有量の小さい高純度水酸化アルミニウムが製造できるため好ましい。また、種結晶水酸化アルミニウムの添加量はアルミン酸ナトリウム中のＡｌ（ＯＨ）3に対して１〜１０重量％、好ましくは３〜７重量％とすることが好ましい。
炭酸ガスによる中和を行う際のアルミン酸ナトリウム水溶液の温度は、多くの場合は０〜１００℃であり、かかる温度範囲で温度が低くなるほど析出する水酸化アルミニウムの平均粒子径が小さくなる一方で、Ｆｅの含有量が低い高純度水酸化アルミニウムが得られる傾向がある。本発明において得られる水酸化アルミニウムの平均粒子径が１０μｍより小さくなると水酸化アルミニウム結晶の表面積が増大して、不純物の結晶表面への吸着が優勢となるのに加え、続く洗浄工程において晶析母液の主成分であるＮａを除去するのに多量の洗浄水を使用しなければならなくなるため好ましくない。従って平均粒子径が１０〜１００μｍ、好ましくは２０〜８０μｍの高純度水酸化アルミニウムが得られるように、炭酸ガスによる中和を行う際のアルミン酸ナトリウム水溶液の温度は、３０〜９０℃、好ましくは４５〜８０℃とすることが特に好ましい。上記温度範囲で中和を行うことにより、鉄含有量を更に低減できる。
Prior to neutralization with carbon dioxide, seed crystal aluminum hydroxide can be added. In this case, there is an advantage that generation of fine crystals can be prevented as compared with the case where the reaction is performed without adding seed crystal aluminum hydroxide. When the high-purity aluminum hydroxide obtained in the present invention is used as the seed crystal aluminum hydroxide to be added at this time, impurities derived from the seed crystal aluminum hydroxide can be reduced and a high-purity aluminum hydroxide with a small impurity content can be produced. This is preferable because it is possible. The amount of seed crystal aluminum hydroxide added is 1 to 10% by weight, preferably 3 to 7% by weight, based on Al (OH) 3 in sodium aluminate.
The temperature of the sodium aluminate aqueous solution at the time of neutralization with carbon dioxide gas is 0 to 100 ° C. in many cases, while the average particle diameter of the precipitated aluminum hydroxide becomes smaller as the temperature becomes lower in this temperature range. , High-purity aluminum hydroxide with a low Fe content tends to be obtained. When the average particle diameter of the aluminum hydroxide obtained in the present invention is smaller than 10 μm, the surface area of the aluminum hydroxide crystal is increased and the adsorption of impurities onto the crystal surface becomes dominant. This is not preferable because a large amount of washing water must be used to remove Na, which is the main component of selenium. Therefore, the temperature of the sodium aluminate aqueous solution when neutralizing with carbon dioxide gas is 30 to 90 ° C., preferably so that high-purity aluminum hydroxide having an average particle diameter of 10 to 100 μm, preferably 20 to 80 μm is obtained. It is especially preferable to set it as 45-80 degreeC. By performing neutralization within the above temperature range, the iron content can be further reduced.
炭酸ガスによる中和を行った後、炭酸ガスの供給を停止し、反応温度はそのままに反応溶液の攪拌を継続することで、高純度水酸化アルミニウムの熟成を行うことができる。上記した反応条件以外に当該熟成工程によっても、高純度水酸化アルミニウムの平均粒子径を制御することが可能である。 After neutralization with carbon dioxide gas, the supply of carbon dioxide gas is stopped, and the reaction solution is kept stirring without changing the reaction temperature, whereby high-purity aluminum hydroxide can be aged. In addition to the reaction conditions described above, the average particle size of the high-purity aluminum hydroxide can be controlled also by the aging step.
得られた高純度水酸化アルミニウムに、必要に応じて濾過、洗浄および乾燥を更に行う。濾過には公知の方法を用いることができ、例えばフィルタープレスにより行うと、濾過が迅速に行え、かつ、反応溶液を大量に処理できることから好ましい。
また、洗浄は純水を用いて行うが、この際キレート剤を添加した純水を用いて洗浄を行うと、高純度水酸化アルミニウム表面に残存する不純物をキレート化して除去することができるため好ましい。キレート剤の添加量は洗浄液量や洗浄回数等により適宜変更することが望ましいが、高純度水酸化アルミニウムに残存する不純物はアルミン酸ナトリウム水溶液中の不純物量よりも低減されていることから、前述したような添加量の範囲で通常は高純度水酸化アルミニウム析出時の使用量よりも少量でよい。
なお、キレート剤が高純度水酸化アルミニウムに残存することで有機不純物となることを防ぐため、最後は純水による洗浄を行うことが好ましい。
本発明の製造方法で得られる高純度水酸化アルミニウムは、鉄の含有量が金属換算で２ｐｐｍ以下、好ましくは１．５ｐｐｍ以下、特に好ましくは１ｐｐｍ以下で、炭素分（ＴＯＣ）の含有量が１００ｐｐｍ以下、好ましくは５０ｐｐｍ以下、特に好ましくは３０ｐｐｍ以下であって、レーザー光散乱法により求められる平均粒子径が１０〜１００μｍ、好ましくは２０〜８０μｍの高純度水酸化アルミニウムであり、本発明の高純度水酸化アルミニウムは特に高性能光学ガラスや電気・電子材料用の製造原料として好適に使用することができる。
The obtained high-purity aluminum hydroxide is further filtered, washed and dried as necessary. A known method can be used for the filtration. For example, it is preferable to use a filter press because filtration can be performed quickly and a large amount of the reaction solution can be processed.
In addition, cleaning is performed using pure water. At this time, cleaning using pure water to which a chelating agent is added is preferable because impurities remaining on the surface of high-purity aluminum hydroxide can be chelated and removed. . It is desirable to change the amount of the chelating agent appropriately depending on the amount of washing solution, the number of washings, etc., but the impurities remaining in the high-purity aluminum hydroxide are reduced as compared with the amount of impurities in the sodium aluminate aqueous solution. In such a range of addition amount, it may be usually smaller than the amount used when depositing high-purity aluminum hydroxide.
In order to prevent the chelating agent from remaining in the high-purity aluminum hydroxide and becoming an organic impurity, it is preferable to finally perform cleaning with pure water.
The high-purity aluminum hydroxide obtained by the production method of the present invention has an iron content of 2 ppm or less, preferably 1.5 ppm or less, particularly preferably 1 ppm or less, and a carbon content (TOC) content of 100 ppm in terms of metal. In the following, it is preferably 50 ppm or less, particularly preferably 30 ppm or less, and high-purity aluminum hydroxide having an average particle diameter determined by a laser light scattering method of 10 to 100 μm, preferably 20 to 80 μm. Aluminum hydroxide can be suitably used particularly as a production raw material for high-performance optical glass and electric / electronic materials.
以下、実施例及び比較例に基づいて、本発明の好適な実施の形態を説明する。
なお、各実施例及び比較例で使用した水はイオン交換樹脂を供えた純水製造装置で処理した水を限外濾過モジュール（旭化学工業社製、分画分子量６０００）で処理したものである。また、不純物量測定、平均粒子径測定及び粒子形状観察は下記の方法で行った。
Hereinafter, preferred embodiments of the present invention will be described based on examples and comparative examples.
In addition, the water used by each Example and the comparative example processed the water processed with the pure water manufacturing apparatus which provided the ion exchange resin with the ultrafiltration module (Asahi Chemical Industry Co., Ltd. make, molecular weight cut off 6000). . The impurity amount measurement, average particle diameter measurement, and particle shape observation were performed by the following methods.
｛不純物分析方法｝
（アルミン酸ナトリウム水溶液中のアルミニウム（Ａｌ）、ナトリウム（Ｎａ）、鉄（Ｆｅ）の分析方法）
アルミン酸ナトリウム水溶液１ｇに硝酸１ｍｌを加えて強酸性にして純水を加えて全量を２０ｇとし、均一溶液を調製した。当該水溶液をＩＣＰ（Ｖａｒｉａｎ社製、ＬＩＢＥＲＴＹ II型）によってアルミニウム、鉄、ナトリウムを定量した。
{Impurity analysis method}
(Analytical method of aluminum (Al), sodium (Na), iron (Fe) in sodium aluminate aqueous solution)
1 g of nitric acid aqueous solution was added to 1 g of sodium aluminate aqueous solution to make it strongly acidic, and pure water was added to make the total amount 20 g to prepare a uniform solution. The aqueous solution was quantified for aluminum, iron and sodium by ICP (manufactured by Varian, LIBERTY type II).
（水酸化アルミニウム中の鉄（Ｆｅ）の分析方法）
水酸化アルミニウム２ｇを純水１０ｍｌに分散させ硝酸４０ｍｌを加えて加熱溶解し、ＩＣＰ（Ｖａｒｉａｎ製ＬＩＢＥＲＴＹ II型）によって定量した。
(Analysis method of iron (Fe) in aluminum hydroxide)
2 g of aluminum hydroxide was dispersed in 10 ml of pure water, 40 ml of nitric acid was added and dissolved by heating, and quantified by ICP (Varian LIBERTY type II).
（試料中の有機物由来炭素量の分析方法）
全有機炭素計（島津製作所製、ＴＯＣ−５０００Ａ）により炭素量を測定した。以下、ＴＯＣ（Ｔｏｔａｌ Ｏｒｇａｎｉｃ Ｃａｒｂｏｎ）量と記載する。
(Analytical method for the amount of organic carbon in the sample)
The amount of carbon was measured using a total organic carbon meter (manufactured by Shimadzu Corporation, TOC-5000A). Hereinafter, it is described as a TOC (Total Organic Carbon) amount.
｛水酸化アルミニウムの平均粒子径の測定｝
マイクロトラック（日機装製 ＨＲＡ型）を用いて、レーザー光散乱法による平均粒子径（Ｄ50）の測定をした。
{Measurement of average particle size of aluminum hydroxide}
The average particle diameter (D 50 ) was measured by a laser light scattering method using a microtrack (Nikkiso HRA type).
｛粒子の形状の観察｝
得られた高純度水酸化アルミニウムをＳＥＭ（日立製作所製Ｓ−４５００型）により観察した。
{Observation of particle shape}
The obtained high-purity aluminum hydroxide was observed by SEM (S-4500, manufactured by Hitachi, Ltd.).
各実施例及び比較例で使用した種結晶水酸化アルミニウム及び粗製アルミン酸ナトリウム水溶液は、下記の方法に従って調製した。 The seed crystal aluminum hydroxide and the crude sodium aluminate aqueous solution used in each example and comparative example were prepared according to the following method.
｛種結晶水酸化アルミニウムの調製｝
市販のアルミン酸ナトリウム水溶液(Ａｌ2Ｏ3=２０ｗｔ％、Ｎａ2Ｏ=１９ｗｔ％、昭和電工株式会社製ＳＡ２０１９)２２５．０ｋｇを７５℃に加熱して、市販の２５ｗｔ％水酸化ナトリウム水溶液１１．１ｋｇおよび純水７１．９ｋｇを混合して、Ａｌ2Ｏ3=１４．６ｗｔ％、Ｎａ2Ｏ=１４．６ｗｔ％のアルミン酸ナトリウム水溶液３０８ｇを作製し、７５℃に保って２時間熟成した。このアルミン酸ナトリウム水溶液に９３ｋｇの純水を加えて、再び７５℃とし、種結晶として市販の水酸化アルミニウム（日本軽金属株式会社製Ｂ５２、水分９ｗｔ％の湿粉）０．４５ｋｇを添加して７５℃を保って２時間熟成した。この過飽和のアルミン酸ナトリウム水溶液を２４時間かけて４５℃まで徐々に冷却し、少量の水酸化アルミニウムを析出させた。析出した水酸化アルミニウムをろ過して、透明度の高いアルミン酸ナトリウム水溶液を得た。このアルミン酸ナトリウム水溶液中の鉄含有量は６．２ｐｐｍであった。また、分離した水酸化アルミニウムは不純物付着で褐色を帯びており、乾燥重量は１１ｋｇであった。次いで、アルミン酸ナトリウム水溶液に炭酸ガスを吹き込んでｐＨ９．５に中和して、水酸化アルミニウムを析出させ、ろ過水洗し、１１０℃で乾燥して、５２ｋｇの水酸化アルミニウムを得た。この水酸化アルミニウムを分析したところ、鉄(Ｆｅ)含有量は４．７ｐｐｍ、ＴＯＣ量は２５０ｐｐｍ、平均粒子径は３μｍであった。
{Preparation of seed crystal aluminum hydroxide}
10. Heat 225.0 kg of a commercially available sodium aluminate aqueous solution (Al 2 O 3 = 20 wt%, Na 2 O = 19 wt%, Showa Denko KK SA2019) to 75 ° C. to obtain a commercially available 25 wt% sodium hydroxide aqueous solution; 1 kg and 71.9 kg of pure water were mixed to prepare 308 g of an aqueous sodium aluminate solution of Al 2 O 3 = 14.6 wt% and Na 2 O = 14.6 wt%, and aged for 2 hours while maintaining at 75 ° C. 93 kg of pure water is added to this aqueous solution of sodium aluminate to 75 ° C., and 0.45 kg of commercially available aluminum hydroxide (B52 manufactured by Nippon Light Metal Co., Ltd., 9 wt% moisture powder) is added as a seed crystal. The mixture was aged for 2 hours while maintaining the temperature. This supersaturated sodium aluminate aqueous solution was gradually cooled to 45 ° C. over 24 hours to precipitate a small amount of aluminum hydroxide. The precipitated aluminum hydroxide was filtered to obtain a sodium aluminate aqueous solution with high transparency. The iron content in this sodium aluminate aqueous solution was 6.2 ppm. Further, the separated aluminum hydroxide was brown with impurities attached, and the dry weight was 11 kg. Next, carbon dioxide was blown into the sodium aluminate aqueous solution to neutralize to pH 9.5, aluminum hydroxide was precipitated, washed with filtered water, and dried at 110 ° C. to obtain 52 kg of aluminum hydroxide. When this aluminum hydroxide was analyzed, the iron (Fe) content was 4.7 ppm, the TOC content was 250 ppm, and the average particle size was 3 μm.
｛粗製アルミン酸ナトリウム水溶液の調製｝
市販の２５ｗｔ％水酸化ナトリウム水溶液８８．８ｋｇに市販の９９ｗｔ％フレーク水酸化ナトリウム２４．０ｋｇを攪拌下に加えて溶解し、次いで市販の水酸化アルミニウム（日本軽金属株式会社製Ｂ５２、水分９ｗｔ％の湿粉、Ｆｅ含有量１５ｐｐｍ、ＴＯＣ量３００ｐｐｍ）６０．０ｋｇを加えて、１０５℃で２時間加熱して水酸化アルミニウムを溶解し、粗製アルミン酸ナトリウム水溶液（Ｆｅ含有量５．２ｐｐｍ、ＴＯＣ量１０４ｐｐｍ）を調製した。
{Preparation of crude sodium aluminate aqueous solution}
In 88.8 kg of a commercially available 25 wt% sodium hydroxide aqueous solution, 24.0 kg of a commercially available 99 wt% flake sodium hydroxide is added and dissolved under stirring, and then commercially available aluminum hydroxide (B52 manufactured by Nippon Light Metal Co., Ltd. Add 60.0 kg of moist powder, Fe content 15 ppm, TOC amount 300 ppm), and heat at 105 ° C. for 2 hours to dissolve aluminum hydroxide. Crude sodium aluminate aqueous solution (Fe content 5.2 ppm, TOC amount 104 ppm) ) Was prepared.
〔実施例１〕
第１工程：先に調製した粗製アルミン酸ナトリウム水溶液を９０℃に保持した後、次亜塩素酸ナトリウム溶液（純正化学株式会社製、試薬、有効塩素（Ｃｌ）濃度８ｗｔ％）１．２ｋｇを純水２０ｋｇで希釈して加えて３時間攪拌を続けて有機物を分解除去した。処理後のＦｅ含有量は４．７ｐｐｍ、ＴＯＣ量は７．７ｐｐｍであった。第２工程：次いで、純水４５．６ｋｇを加え、７５℃まで冷却し、種結晶水酸化アルミニウム４．４ｋｇを加えて２時間加水分解を行って水酸化アルミニウムを析出させた。析出した水酸化アルミニウムをろ過により分離除去し、透明度が高く無色のアルミン酸ナトリウム水溶液を得た。このアルミン酸ナトリウム水溶液中の鉄含有量は４．４ｐｐｍ、ＴＯＣ量は６．２ｐｐｍであった。また、ろ過により分離された水酸化アルミニウムは８．５６ｋｇであったことから、粗製アルミン酸ナトリウム水溶液中から析出した水酸化アルミニウム（種結晶として加えた水酸化アルミニウムを除く）は４．１５ｋｇであった。したがって、この工程における粗製アルミン酸ナトリウム水溶液中からの水酸化アルミニウム析出量は、粗製アルミン酸ナトリウム水溶液中の全アルミニウム量に対して７．７重量％であった。第３工程：このアルミン酸ナトリウム溶液に、純水７５．５ｋｇに０．４５ｋｇのエチレンジアミン四酢酸四ナトリウム四水和物（ＥＤＴＡ）（純正化学株式会社製、試薬）を溶解して調製したＥＤＴＡ水溶液と種結晶水酸化アルミニウム１．４９ｋｇを加えて攪拌分散し、再び９０℃まで加熱した。９０℃を保ったままアルミン酸ナトリウム水溶液に炭酸ガスを吹き込んでｐＨ１０．０まで中和して、水酸化アルミニウムを析出させた。水酸化アルミニウムはろ過した後、０．０５ｋｇのＥＤＴＡを溶解した純水４００リットルにリパルプし、更にろ過・純水（ＥＤＴＡを含まない）リパルプを２回繰り返すことで洗浄を行った。その後、１１０℃で乾燥し、４４．７ｋｇの高純度水酸化アルミニウムを得た。得られた高純度水酸化アルミニウムの鉄（Ｆｅ）含有量、ＴＯＣ量、平均粒子径（Ｄ50）を表１に示す。また、ＳＥＭ観察では粒子は５〜９μｍの一次粒子の凝集体であることが判った。
[Example 1]
First step: After maintaining the previously prepared crude sodium aluminate aqueous solution at 90 ° C., 1.2 kg of sodium hypochlorite solution (manufactured by Junsei Chemical Co., Ltd., reagent, effective chlorine (Cl) concentration 8 wt%) is purified. The mixture was diluted with 20 kg of water and stirred for 3 hours to decompose and remove organic substances. The Fe content after the treatment was 4.7 ppm, and the TOC amount was 7.7 ppm. Second step: Next, 45.6 kg of pure water was added, the mixture was cooled to 75 ° C., 4.4 kg of seed crystal aluminum hydroxide was added, and hydrolysis was performed for 2 hours to precipitate aluminum hydroxide. The precipitated aluminum hydroxide was separated and removed by filtration to obtain a colorless sodium aluminate aqueous solution with high transparency. The iron content in this aqueous sodium aluminate solution was 4.4 ppm, and the TOC content was 6.2 ppm. Since aluminum hydroxide separated by filtration was 8.56 kg, aluminum hydroxide precipitated from the crude sodium aluminate aqueous solution (excluding aluminum hydroxide added as a seed crystal) was 4.15 kg. It was. Therefore, the amount of aluminum hydroxide precipitated from the crude sodium aluminate aqueous solution in this step was 7.7% by weight based on the total amount of aluminum in the crude sodium aluminate aqueous solution. Third step: An aqueous EDTA solution prepared by dissolving 0.45 kg of ethylenediaminetetraacetic acid tetrasodium tetrahydrate (EDTA) (produced by Junsei Chemical Co., Ltd.) in 75.5 kg of pure water in this sodium aluminate solution. And 1.49 kg of seed crystal aluminum hydroxide were added, dispersed with stirring, and heated again to 90 ° C. While maintaining 90 ° C., carbon dioxide was blown into the sodium aluminate aqueous solution to neutralize to pH 10.0 to precipitate aluminum hydroxide. The aluminum hydroxide was filtered, repulped into 400 liters of pure water in which 0.05 kg of EDTA was dissolved, and further washed by repeating filtration and pure water (without EDTA) repulp twice. Then, it dried at 110 degreeC and obtained 44.7 kg of high purity aluminum hydroxide. Table 1 shows the iron (Fe) content, the TOC amount, and the average particle diameter (D 50 ) of the obtained high-purity aluminum hydroxide. In addition, SEM observation revealed that the particles were aggregates of primary particles of 5 to 9 μm.
〔実施例２〕
実施例１の第３工程において、使用したキレート剤をニトリロトリスメチレンホスホン酸（以下、ＮＴＰと記載）に代えた以外は実施例１と同じ方法で高純度水酸化アルミニウムを作製した。ＮＴＰは日本化学工業株式会社より販売されている５０ｗｔ％ＮＴＰ水溶液（商品名「デフロックＮＨ０５」）を使用した。使用量は、アルミン酸ナトリウムへの添加を０．２６ｋｇ、洗浄時の添加を０．１３ｋｇとした。得られた高純度水酸化アルミニウムの鉄（Ｆｅ）含有量、ＴＯＣ量、平均粒子径（Ｄ50）を表１に示す。また、ＳＥＭ観察では粒子は５〜９μｍの一次粒子の凝集体であることが判った。
[Example 2]
In the third step of Example 1, high-purity aluminum hydroxide was prepared in the same manner as in Example 1 except that the chelating agent used was replaced with nitrilotrismethylenephosphonic acid (hereinafter referred to as NTP). As the NTP, a 50 wt% NTP aqueous solution (trade name “Deflock NH05”) sold by Nippon Chemical Industry Co., Ltd. was used. The amount used was 0.26 kg for sodium aluminate and 0.13 kg for washing. Table 1 shows the iron (Fe) content, the TOC amount, and the average particle diameter (D 50 ) of the obtained high-purity aluminum hydroxide. In addition, SEM observation revealed that the particles were aggregates of primary particles of 5 to 9 μm.
〔実施例３〕
実施例１の第３工程において、水酸化アルミニウムの洗浄時にキレート剤を使用せず、純水のみで洗浄を行った以外は実施例１と同じ方法で高純度水酸化アルミニウムを作製した。得られた高純度水酸化アルミニウムの鉄（Ｆｅ）含有量、ＴＯＣ量、平均粒子径（Ｄ50）を表１に示す。また、ＳＥＭ観察では粒子は５〜９μｍの一次粒子の凝集体であることが判った。
Example 3
In the third step of Example 1, a high-purity aluminum hydroxide was produced in the same manner as in Example 1 except that the chelating agent was not used at the time of washing aluminum hydroxide and washing was performed only with pure water. Table 1 shows the iron (Fe) content, the TOC amount, and the average particle diameter (D 50 ) of the obtained high-purity aluminum hydroxide. In addition, SEM observation revealed that the particles were aggregates of primary particles of 5 to 9 μm.
〔実施例４〕
実施例１の第２工程において、高純度水酸化アルミニウム析出用種結晶として用いた水酸化アルミニウムの代わりに実施例１で得られた高純度水酸化アルミニウムを用いた以外は実施例１と同じ方法で高純度水酸化アルミニウムを作製した。得られた高純度水酸化アルミニウムの鉄（Ｆｅ）含有量、ＴＯＣ量、平均粒子径（Ｄ50）を表１に示す。また、ＳＥＭ観察では粒子は５〜９μｍの一次粒子の凝集体であることが判った。
Example 4
In the second step of Example 1, the same method as in Example 1 except that the high purity aluminum hydroxide obtained in Example 1 was used instead of the aluminum hydroxide used as the seed crystal for high purity aluminum hydroxide precipitation. A high purity aluminum hydroxide was prepared. Table 1 shows the iron (Fe) content, the TOC amount, and the average particle diameter (D 50 ) of the obtained high-purity aluminum hydroxide. In addition, SEM observation revealed that the particles were aggregates of primary particles of 5 to 9 μm.
〔実施例５〕
実施例１の第２工程において、高純度水酸化アルミニウム析出用種結晶として市販の平均粒子径１．３μｍの水酸化アルミニウム（日軽金属社製、商品名ＢＦ０１３；鉄（Ｆｅ）含有量２８ｐｐｍ、ＴＯＣ量７０ｐｐｍ）を用い、第３工程において、６０℃を保ったままアルミン酸ナトリウム水溶液に炭酸ガスを吹き込んでｐＨ１０．６まで中和して、水酸化アルミニウムを析出させた以外は実施例１と同じ方法で高純度水酸化アルミニウムを作製した。得られた高純度水酸化アルミニウムの鉄（Ｆｅ）含有量、ＴＯＣ量、平均粒子径（Ｄ50）を表１に示す。また、ＳＥＭ観察では粒子は４〜７μｍの一次粒子の凝集体であることが判った。
Example 5
In the second step of Example 1, a commercially available aluminum hydroxide having an average particle size of 1.3 μm as a seed crystal for precipitation of high-purity aluminum hydroxide (manufactured by Nikkei Metals, trade name BF013; iron (Fe) content 28 ppm, TOC The amount was 70 ppm), and in the third step, carbon dioxide gas was blown into the aqueous sodium aluminate solution while maintaining 60 ° C. to neutralize to pH 10.6, thereby precipitating aluminum hydroxide. High-purity aluminum hydroxide was produced by this method. Table 1 shows the iron (Fe) content, the TOC amount, and the average particle diameter (D 50 ) of the obtained high-purity aluminum hydroxide. In addition, SEM observation revealed that the particles were aggregates of primary particles of 4 to 7 μm.
〔比較例１〕
実施例１の第３工程の水酸化アルミニウム析出工程でキレート剤を使用せず、また、純水のみで水酸化アルミニウムの洗浄を行った以外は実施例１と同じ方法で高純度水酸化アルミニウムを作製した。得られた水酸化アルミニウムの鉄（Ｆｅ）含有量、ＴＯＣ量、平均粒子径（Ｄ50）を表１に示す。また、ＳＥＭ観察では粒子は５〜９μｍの一次粒子の凝集体であることが判った。
[Comparative Example 1]
The high-purity aluminum hydroxide was obtained in the same manner as in Example 1 except that the chelating agent was not used in the aluminum hydroxide precipitation step of Example 3 and that the aluminum hydroxide was washed only with pure water. Produced. Table 1 shows the iron (Fe) content, the TOC amount, and the average particle diameter (D 50 ) of the obtained aluminum hydroxide. In addition, SEM observation revealed that the particles were aggregates of primary particles of 5 to 9 μm.
〔比較例２〕
実施例１の第３工程の水酸化アルミニウム析出工程でキレート剤を使用せず、キレート剤を添加した水で水酸化アルミニウムの洗浄を行った以外は実施例１と同じ方法で水酸化アルミニウムを作製した。得られた水酸化アルミニウムの鉄（Ｆｅ）含有量、ＴＯＣ量、平均粒子径（Ｄ50）を表１に示す。また、ＳＥＭ観察では粒子は５〜９μｍの一次粒子の凝集体であることが判った。
[Comparative Example 2]
Aluminum hydroxide was produced in the same manner as in Example 1 except that the chelating agent was not used in the aluminum hydroxide precipitation step of Example 3 and that the aluminum hydroxide was washed with water to which the chelating agent was added. did. Table 1 shows the iron (Fe) content, the TOC amount, and the average particle diameter (D 50 ) of the obtained aluminum hydroxide. In addition, SEM observation revealed that the particles were aggregates of primary particles of 5 to 9 μm.
表１より、アルミン酸ナトリウム水溶液にキレート剤を添加することで、鉄含有量が低減できることがわかる。
また、実施例１と実施例４の比較から、高純度水酸化アルミニウム析出用の種結晶として本発明により得られた高純度水酸化アルミニウムを用いることで、鉄不純物を更に低減させた高純度水酸化アルミニウムを製造することが可能であることがわかる。
更に、実施例１と実施例３の比較から、高純度水酸化アルミニウム洗浄時にキレート剤を用いることで、鉄含有量を更に低減できることがわかる。
また、実施例１と実施例５の比較から、種結晶として平均粒子径が２μｍ以下の水酸化アルミニウムを用い、炭酸ガスによる中和を６０℃で行うことで、鉄含有量を更に低減できることがわかる。
本発明に係る高純度水酸化アルミニウムの製造方法によれば、水酸化アルミニウム中の鉄不純物含有量が２ｐｐｍ以下であり、かつ、炭素分（ＴＯＣ）の含有量が１００ｐｐｍ以下である、平均粒子径が１０〜１００μｍの高純度水酸化アルミニウムを簡便な一連の工程により製造することができることがわかる。
Table 1 shows that iron content can be reduced by adding a chelating agent to sodium aluminate aqueous solution.
Further, from the comparison between Example 1 and Example 4, by using the high-purity aluminum hydroxide obtained by the present invention as a seed crystal for high-purity aluminum hydroxide precipitation, high-purity water in which iron impurities are further reduced It can be seen that aluminum oxide can be produced.
Furthermore, the comparison between Example 1 and Example 3 shows that the iron content can be further reduced by using a chelating agent during high-purity aluminum hydroxide cleaning.
Further, from the comparison between Example 1 and Example 5, the iron content can be further reduced by using aluminum hydroxide having an average particle diameter of 2 μm or less as a seed crystal and neutralizing with carbon dioxide gas at 60 ° C. Recognize.
According to the method for producing high-purity aluminum hydroxide according to the present invention, the average particle diameter is such that the content of iron impurities in aluminum hydroxide is 2 ppm or less and the content of carbon (TOC) is 100 ppm or less. It can be seen that high-purity aluminum hydroxide having a thickness of 10 to 100 μm can be produced by a series of simple steps.
Claims (8)
該有機物が分解されたアルミン酸ナトリウム水溶液に種結晶水酸化アルミニウムと水とを添加し、水酸化アルミニウムを析出させ、析出した水酸化アルミニウムを該水酸化アルミニウムに付着した不純物とともに該アルミン酸ナトリウム水溶液から分離除去する第２工程、及び
該不純物が除去されたアルミン酸ナトリウム水溶液にキレート剤を添加した後、炭酸ガスを吹き込み、高純度水酸化アルミニウムを析出させる第３工程
をこの順に行うことを特徴とする高純度水酸化アルミニウムの製造方法。 A first step of decomposing an organic substance by causing an oxidizing agent to act on a crude sodium aluminate aqueous solution;
Seed aluminum hydroxide and water are added to the sodium aluminate aqueous solution in which the organic matter is decomposed to precipitate aluminum hydroxide, and the precipitated aluminum hydroxide together with impurities adhering to the aluminum hydroxide is added to the sodium aluminate aqueous solution. A second step of separating and removing from the aqueous solution, and a third step of adding a chelating agent to the aqueous sodium aluminate solution from which the impurities have been removed, and then blowing carbon dioxide to precipitate high-purity aluminum hydroxide in this order. A method for producing high-purity aluminum hydroxide.
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| EP2319803B1 (en) | 2008-08-19 | 2013-10-09 | Kyowa Chemical Industry Co., Ltd. | Aluminum hydroxide gel particles and process for production of same |
| KR100996472B1 (en) * | 2010-04-16 | 2010-11-25 | 주식회사 해마루에너지 | Method for manufacturing high purity aluminium trihydroxide |
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| JPS48101400A (en) * | 1972-04-04 | 1973-12-20 | ||
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| FR2591581B1 (en) * | 1985-12-17 | 1990-05-25 | Pechiney Aluminium | PROCESS FOR OBTAINING HIGH PRODUCTIVITY OF ALUMINUM TRIHYDROXIDE, HIGH PURITY AND MEDIAN DIAMETER LESS THAN 4 MICROMETERS, ADJUSTED ON REQUEST. |
| JP2579773B2 (en) * | 1987-07-20 | 1997-02-12 | 住友化学工業株式会社 | Purification method of alkaline solution |
| JP3382648B2 (en) * | 1992-12-02 | 2003-03-04 | 住友化学工業株式会社 | Method for producing white aluminum hydroxide |
| JP3555206B2 (en) * | 1994-12-27 | 2004-08-18 | 住友化学工業株式会社 | Method for producing sodium aluminate solution |
| JPH08325011A (en) * | 1995-05-26 | 1996-12-10 | Showa Denko Kk | Aluminum hydroxide and its production |
| JP3651245B2 (en) * | 1998-03-27 | 2005-05-25 | 日本軽金属株式会社 | Method for producing high purity aluminum hydroxide |
| JP4217065B2 (en) * | 2002-12-25 | 2009-01-28 | 昭和電工株式会社 | Method for purifying sodium aluminate solution and method for producing aluminum hydroxide |
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