JPS62176923A - Preparation of goethite - Google Patents
Preparation of goethiteInfo
- Publication number
- JPS62176923A JPS62176923A JP61017027A JP1702786A JPS62176923A JP S62176923 A JPS62176923 A JP S62176923A JP 61017027 A JP61017027 A JP 61017027A JP 1702786 A JP1702786 A JP 1702786A JP S62176923 A JPS62176923 A JP S62176923A
- Authority
- JP
- Japan
- Prior art keywords
- oxidation
- suspension
- goethite
- ferrous
- added
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
- 229910052598 goethite Inorganic materials 0.000 title claims abstract description 44
- AEIXRCIKZIZYPM-UHFFFAOYSA-M hydroxy(oxo)iron Chemical compound [O][Fe]O AEIXRCIKZIZYPM-UHFFFAOYSA-M 0.000 title claims abstract description 44
- 238000007254 oxidation reaction Methods 0.000 claims abstract description 48
- 230000003647 oxidation Effects 0.000 claims abstract description 33
- 239000000725 suspension Substances 0.000 claims abstract description 27
- 230000002378 acidificating effect Effects 0.000 claims abstract description 21
- BAUYGSIQEAFULO-UHFFFAOYSA-L iron(2+) sulfate (anhydrous) Chemical compound [Fe+2].[O-]S([O-])(=O)=O BAUYGSIQEAFULO-UHFFFAOYSA-L 0.000 claims abstract description 20
- 229910021506 iron(II) hydroxide Inorganic materials 0.000 claims abstract description 18
- NCNCGGDMXMBVIA-UHFFFAOYSA-L iron(ii) hydroxide Chemical compound [OH-].[OH-].[Fe+2] NCNCGGDMXMBVIA-UHFFFAOYSA-L 0.000 claims abstract description 18
- 239000000126 substance Substances 0.000 claims abstract description 18
- 239000003513 alkali Substances 0.000 claims abstract description 7
- 230000001590 oxidative effect Effects 0.000 claims abstract description 4
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims description 26
- 239000007864 aqueous solution Substances 0.000 claims description 10
- 229910052742 iron Inorganic materials 0.000 claims description 6
- 238000004519 manufacturing process Methods 0.000 claims description 6
- 239000002245 particle Substances 0.000 abstract description 35
- 238000000034 method Methods 0.000 abstract description 30
- 239000006247 magnetic powder Substances 0.000 abstract description 13
- QTBSBXVTEAMEQO-UHFFFAOYSA-N Acetic acid Chemical compound CC(O)=O QTBSBXVTEAMEQO-UHFFFAOYSA-N 0.000 abstract description 12
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 abstract description 11
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 abstract description 11
- 239000002244 precipitate Substances 0.000 abstract description 9
- CWYNVVGOOAEACU-UHFFFAOYSA-N Fe2+ Chemical compound [Fe+2] CWYNVVGOOAEACU-UHFFFAOYSA-N 0.000 abstract description 6
- 238000006386 neutralization reaction Methods 0.000 abstract description 5
- 239000002253 acid Substances 0.000 abstract description 4
- 238000001556 precipitation Methods 0.000 abstract description 3
- 229910001448 ferrous ion Inorganic materials 0.000 abstract description 2
- 239000000463 material Substances 0.000 abstract 1
- 235000011149 sulphuric acid Nutrition 0.000 abstract 1
- 238000006243 chemical reaction Methods 0.000 description 21
- 239000013078 crystal Substances 0.000 description 17
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 12
- 230000000052 comparative effect Effects 0.000 description 12
- 239000000843 powder Substances 0.000 description 11
- 239000000243 solution Substances 0.000 description 11
- UQSXHKLRYXJYBZ-UHFFFAOYSA-N Iron oxide Chemical compound [Fe]=O UQSXHKLRYXJYBZ-UHFFFAOYSA-N 0.000 description 10
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 8
- 239000001301 oxygen Substances 0.000 description 8
- 229910052760 oxygen Inorganic materials 0.000 description 8
- 239000010419 fine particle Substances 0.000 description 7
- 239000007789 gas Substances 0.000 description 7
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 6
- KWYUFKZDYYNOTN-UHFFFAOYSA-M Potassium hydroxide Chemical compound [OH-].[K+] KWYUFKZDYYNOTN-UHFFFAOYSA-M 0.000 description 6
- 238000003756 stirring Methods 0.000 description 6
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 6
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 description 5
- 239000011790 ferrous sulphate Substances 0.000 description 5
- 235000003891 ferrous sulphate Nutrition 0.000 description 5
- 229910000359 iron(II) sulfate Inorganic materials 0.000 description 5
- 239000007788 liquid Substances 0.000 description 5
- 239000002994 raw material Substances 0.000 description 5
- NBIIXXVUZAFLBC-UHFFFAOYSA-N Phosphoric acid Chemical compound OP(O)(O)=O NBIIXXVUZAFLBC-UHFFFAOYSA-N 0.000 description 4
- CDBYLPFSWZWCQE-UHFFFAOYSA-L Sodium Carbonate Chemical compound [Na+].[Na+].[O-]C([O-])=O CDBYLPFSWZWCQE-UHFFFAOYSA-L 0.000 description 4
- 230000000694 effects Effects 0.000 description 4
- 239000001257 hydrogen Substances 0.000 description 4
- 229910052739 hydrogen Inorganic materials 0.000 description 4
- 239000007858 starting material Substances 0.000 description 4
- 238000004438 BET method Methods 0.000 description 3
- MUBZPKHOEPUJKR-UHFFFAOYSA-N Oxalic acid Chemical compound OC(=O)C(O)=O MUBZPKHOEPUJKR-UHFFFAOYSA-N 0.000 description 3
- KRKNYBCHXYNGOX-UHFFFAOYSA-N citric acid Chemical compound OC(=O)CC(O)(C(O)=O)CC(O)=O KRKNYBCHXYNGOX-UHFFFAOYSA-N 0.000 description 3
- 239000012530 fluid Substances 0.000 description 3
- JEIPFZHSYJVQDO-UHFFFAOYSA-N iron(III) oxide Inorganic materials O=[Fe]O[Fe]=O JEIPFZHSYJVQDO-UHFFFAOYSA-N 0.000 description 3
- 239000007800 oxidant agent Substances 0.000 description 3
- 229910000859 α-Fe Inorganic materials 0.000 description 3
- VTYYLEPIZMXCLO-UHFFFAOYSA-L Calcium carbonate Chemical compound [Ca+2].[O-]C([O-])=O VTYYLEPIZMXCLO-UHFFFAOYSA-L 0.000 description 2
- KRHYYFGTRYWZRS-UHFFFAOYSA-N Fluorane Chemical compound F KRHYYFGTRYWZRS-UHFFFAOYSA-N 0.000 description 2
- AEMRFAOFKBGASW-UHFFFAOYSA-N Glycolic acid Chemical compound OCC(O)=O AEMRFAOFKBGASW-UHFFFAOYSA-N 0.000 description 2
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 description 2
- FAPWRFPIFSIZLT-UHFFFAOYSA-M Sodium chloride Chemical compound [Na+].[Cl-] FAPWRFPIFSIZLT-UHFFFAOYSA-M 0.000 description 2
- 150000007513 acids Chemical class 0.000 description 2
- 229910021529 ammonia Inorganic materials 0.000 description 2
- 239000011248 coating agent Substances 0.000 description 2
- 238000000576 coating method Methods 0.000 description 2
- 230000007423 decrease Effects 0.000 description 2
- JVTAAEKCZFNVCJ-UHFFFAOYSA-N lactic acid Chemical compound CC(O)C(O)=O JVTAAEKCZFNVCJ-UHFFFAOYSA-N 0.000 description 2
- BDAGIHXWWSANSR-UHFFFAOYSA-N methanoic acid Natural products OC=O BDAGIHXWWSANSR-UHFFFAOYSA-N 0.000 description 2
- 150000007522 mineralic acids Chemical class 0.000 description 2
- 229910017604 nitric acid Inorganic materials 0.000 description 2
- 235000011007 phosphoric acid Nutrition 0.000 description 2
- 239000012266 salt solution Substances 0.000 description 2
- 239000002002 slurry Substances 0.000 description 2
- 229910000029 sodium carbonate Inorganic materials 0.000 description 2
- 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
- FEWJPZIEWOKRBE-JCYAYHJZSA-N Dextrotartaric acid Chemical compound OC(=O)[C@H](O)[C@@H](O)C(O)=O FEWJPZIEWOKRBE-JCYAYHJZSA-N 0.000 description 1
- MYMOFIZGZYHOMD-UHFFFAOYSA-N Dioxygen Chemical compound O=O MYMOFIZGZYHOMD-UHFFFAOYSA-N 0.000 description 1
- CKLJMWTZIZZHCS-REOHCLBHSA-N L-aspartic acid Chemical compound OC(=O)[C@@H](N)CC(O)=O CKLJMWTZIZZHCS-REOHCLBHSA-N 0.000 description 1
- 229910002651 NO3 Inorganic materials 0.000 description 1
- NHNBFGGVMKEFGY-UHFFFAOYSA-N Nitrate Chemical compound [O-][N+]([O-])=O NHNBFGGVMKEFGY-UHFFFAOYSA-N 0.000 description 1
- 229910019142 PO4 Inorganic materials 0.000 description 1
- OFOBLEOULBTSOW-UHFFFAOYSA-N Propanedioic acid Natural products OC(=O)CC(O)=O OFOBLEOULBTSOW-UHFFFAOYSA-N 0.000 description 1
- PMZURENOXWZQFD-UHFFFAOYSA-L Sodium Sulfate Chemical compound [Na+].[Na+].[O-]S([O-])(=O)=O PMZURENOXWZQFD-UHFFFAOYSA-L 0.000 description 1
- 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 1
- 238000009825 accumulation Methods 0.000 description 1
- 235000011054 acetic acid Nutrition 0.000 description 1
- 239000000654 additive Substances 0.000 description 1
- 229910045601 alloy Inorganic materials 0.000 description 1
- 239000000956 alloy Substances 0.000 description 1
- JZQOJFLIJNRDHK-CMDGGOBGSA-N alpha-irone Chemical compound CC1CC=C(C)C(\C=C\C(C)=O)C1(C)C JZQOJFLIJNRDHK-CMDGGOBGSA-N 0.000 description 1
- AZDRQVAHHNSJOQ-UHFFFAOYSA-N alumane Chemical class [AlH3] AZDRQVAHHNSJOQ-UHFFFAOYSA-N 0.000 description 1
- 229910000147 aluminium phosphate Inorganic materials 0.000 description 1
- 235000001014 amino acid Nutrition 0.000 description 1
- 150000001413 amino acids Chemical class 0.000 description 1
- 150000001495 arsenic compounds Chemical class 0.000 description 1
- 235000003704 aspartic acid Nutrition 0.000 description 1
- OQFSQFPPLPISGP-UHFFFAOYSA-N beta-carboxyaspartic acid Natural products OC(=O)C(N)C(C(O)=O)C(O)=O OQFSQFPPLPISGP-UHFFFAOYSA-N 0.000 description 1
- 238000007664 blowing Methods 0.000 description 1
- 229910000019 calcium carbonate Inorganic materials 0.000 description 1
- BVKZGUZCCUSVTD-UHFFFAOYSA-N carbonic acid Chemical compound OC(O)=O BVKZGUZCCUSVTD-UHFFFAOYSA-N 0.000 description 1
- 150000001735 carboxylic acids Chemical class 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 235000015165 citric acid Nutrition 0.000 description 1
- 229910017052 cobalt Inorganic materials 0.000 description 1
- 239000010941 cobalt Substances 0.000 description 1
- GUTLYIVDDKVIGB-UHFFFAOYSA-N cobalt atom Chemical compound [Co] GUTLYIVDDKVIGB-UHFFFAOYSA-N 0.000 description 1
- 150000001869 cobalt compounds Chemical class 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 238000002425 crystallisation Methods 0.000 description 1
- 230000008025 crystallization Effects 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 230000018044 dehydration Effects 0.000 description 1
- 238000006297 dehydration reaction Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 235000014113 dietary fatty acids Nutrition 0.000 description 1
- 229910001882 dioxygen Inorganic materials 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- 239000000194 fatty acid Substances 0.000 description 1
- 229930195729 fatty acid Natural products 0.000 description 1
- 150000004665 fatty acids Chemical class 0.000 description 1
- 229960004887 ferric hydroxide Drugs 0.000 description 1
- 229960002089 ferrous chloride Drugs 0.000 description 1
- 238000011049 filling Methods 0.000 description 1
- 238000001914 filtration Methods 0.000 description 1
- 235000019253 formic acid Nutrition 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 229910052500 inorganic mineral Inorganic materials 0.000 description 1
- 150000002505 iron Chemical class 0.000 description 1
- NMCUIPGRVMDVDB-UHFFFAOYSA-L iron dichloride Chemical compound Cl[Fe]Cl NMCUIPGRVMDVDB-UHFFFAOYSA-L 0.000 description 1
- 239000001034 iron oxide pigment Substances 0.000 description 1
- IEECXTSVVFWGSE-UHFFFAOYSA-M iron(3+);oxygen(2-);hydroxide Chemical compound [OH-].[O-2].[Fe+3] IEECXTSVVFWGSE-UHFFFAOYSA-M 0.000 description 1
- SZVJSHCCFOBDDC-UHFFFAOYSA-N iron(II,III) oxide Inorganic materials O=[Fe]O[Fe]O[Fe]=O SZVJSHCCFOBDDC-UHFFFAOYSA-N 0.000 description 1
- 239000004310 lactic acid Substances 0.000 description 1
- 235000014655 lactic acid Nutrition 0.000 description 1
- 239000000696 magnetic material Substances 0.000 description 1
- 230000005415 magnetization Effects 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
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 235000010755 mineral Nutrition 0.000 description 1
- 239000011707 mineral Substances 0.000 description 1
- 239000012452 mother liquor Substances 0.000 description 1
- 230000003472 neutralizing effect Effects 0.000 description 1
- 150000002816 nickel compounds Chemical class 0.000 description 1
- 238000010899 nucleation Methods 0.000 description 1
- 230000006911 nucleation Effects 0.000 description 1
- 150000007524 organic acids Chemical class 0.000 description 1
- 235000005985 organic acids Nutrition 0.000 description 1
- 235000006408 oxalic acid Nutrition 0.000 description 1
- 235000021317 phosphate Nutrition 0.000 description 1
- 150000003013 phosphoric acid derivatives Chemical class 0.000 description 1
- 239000011574 phosphorus Substances 0.000 description 1
- 229910052698 phosphorus Inorganic materials 0.000 description 1
- -1 phosphorus compound Chemical class 0.000 description 1
- 239000000047 product Substances 0.000 description 1
- 230000035484 reaction time Effects 0.000 description 1
- 239000011435 rock Substances 0.000 description 1
- 150000004760 silicates Chemical class 0.000 description 1
- 150000003377 silicon compounds Chemical class 0.000 description 1
- 239000011780 sodium chloride Substances 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
- 229910052938 sodium sulfate Inorganic materials 0.000 description 1
- 235000011152 sodium sulphate Nutrition 0.000 description 1
- 235000002906 tartaric acid Nutrition 0.000 description 1
- 239000011975 tartaric acid Substances 0.000 description 1
- VZCYOOQTPOCHFL-UHFFFAOYSA-N trans-butenedioic acid Natural products OC(=O)C=CC(O)=O VZCYOOQTPOCHFL-UHFFFAOYSA-N 0.000 description 1
- RYFMWSXOAZQYPI-UHFFFAOYSA-K trisodium phosphate Chemical compound [Na+].[Na+].[Na+].[O-]P([O-])([O-])=O RYFMWSXOAZQYPI-UHFFFAOYSA-K 0.000 description 1
- 238000005406 washing Methods 0.000 description 1
- 150000003752 zinc compounds Chemical class 0.000 description 1
Landscapes
- Compounds Of Iron (AREA)
- Hard Magnetic Materials (AREA)
Abstract
Description
【発明の詳細な説明】
［産業上の利用分野］
本発明はゲーサイト（α−オキシ水酸化鉄：α−Ｆ ｅ
ＯＯＨ）針状晶結晶、さらに詳しくは主として磁気記
録媒体用の酸化鉄粉末や金属鉄粉末等の原料として好適
なゲーサイトの製造方法に関する。[Detailed Description of the Invention] [Industrial Application Field] The present invention is directed to the use of goethite (α-iron oxyhydroxide: α-Fe
The present invention relates to a method for producing goethite, which is suitable as a raw material for iron oxide powder, metallic iron powder, etc. mainly for magnetic recording media.
［発明の技術的背景］
γ−Ｆｅ２０ｎ、Ｆ ｅ、０．、ベルトライド化合物な
どの酸化鉄粉末またはそれらにコバルト化合物を変成処
理したコバルト含有酸化鉄粉末や金属鉄またはその合金
の粉末などの磁性粉末は、オーディオ用、ビデオ用、コ
ンピューター用等の磁気テープ、磁気ディスク、磁気カ
ード等記録媒体用磁性材料として広く利用されてきてい
るが、近年磁気記録媒体の高記録密度化、高Ｓ／Ｎ比化
の要請が一段と強まってきている。この指向とあいまっ
て磁気記録媒体用磁性粉末は、より小さな粒子（微粒子
化）でより形状の整った（軸比）、枝分れがなくかつ粒
度分布の小さいものが強く求められている。しかして針
状晶ゲーサイトより製造された酸化鉄粉末や金属鉄粉末
等の磁性粉末の粒子構造は、出発物質である針状晶ゲー
サイトの性状に大きく依存するため、使用するゲーサイ
トの粒径、粒子形状、粒度分布等のコントロールがきわ
めて重要とされている。[Technical background of the invention] γ-Fe20n, Fe, 0. Magnetic powders such as iron oxide powders such as bertolide compounds, cobalt-containing iron oxide powders obtained by modifying them with cobalt compounds, and powders of metallic iron or its alloys are used for magnetic tapes for audio, video, computers, etc. Although it has been widely used as a magnetic material for recording media such as magnetic disks and magnetic cards, in recent years there has been a growing demand for higher recording densities and higher S/N ratios in magnetic recording media. Coupled with this trend, there is a strong demand for magnetic powders for magnetic recording media that have smaller particles (micronization), a more regular shape (axial ratio), no branching, and a narrow particle size distribution. However, the particle structure of magnetic powders such as iron oxide powder and metallic iron powder produced from acicular goethite largely depends on the properties of the acicular goethite that is the starting material. Control of diameter, particle shape, particle size distribution, etc. is extremely important.
ところで、ゲーサイトの製法は、大別して酸性側で反応
をおこなう方法（酸性法）とアルカリ性側でおこなう方
法（アルカリ法）とがあるが、前記酸性法は、通常第一
鉄塩水溶液に第一鉄塩に対して当量以下のアルカリを加
えることにより鉄分の一部を水酸化第一鉄の沈殿となし
、次いでこの懸濁液に空気等の酸素含有ガスを導入して
水酸化第一鉄のほぼ実質的全部を酸化してゲーサイト化
し、さらに必要に応じ、残存している第一鉄イオンをア
ルカリを加えて引続き酸化してゲーサイトに転じて所望
の粒子ｒ＆長をはかる方法である。よく知られているよ
うに前記ゲーサイト化反応においては、一般に前記の水
酸化第一鉄沈殿を含んだ懸濁液は、酸化が進むにつれて
青白色の水酸化第一鉄の沈殿がグリーンラスト（一般に
Ｆｅ０−ｎＦｅ２Ｏ，・ｌｌｌＨ２Ｏとして示される）
を経由して濃青色を呈し、酸化率がほぼ２０〜６５％に
なると水酸化第一鉄の沈殿がほぼ消失するとともにグリ
ーンラストの生成、蓄積が増大し膣液のｐ）ｌは６．５
〜８．５から５〜６にまで急速に低下する。（第一＊ｐ
１１屈曲点）次いで引続き酸化を継続すると膣液は緑色
に変化するとともに核晶の生成、成長が進み針状晶のゲ
ーサイト（黄色）へ転化して酸化をほぼ終了するが、こ
れにともなって膣液のｐｉは３〜４にまで比較的急速に
低下する。（第２次ｐＨ屈曲点）しかして前記酸性法に
よるゲーサイトの製法は、アルカリ法の場合に比して樹
枝状に分枝したいわゆる枝分れ結晶が発生し易かったり
、また成長反応途中で核発生が起り易かったりして、粒
度分布巾の狭い均一形状のものを得るのが容易でない反
面、生産コストが比較的安く工業的に有利であるところ
から磁気記録媒体用磁性粉の多くは酸性法で製造した針
状晶ゲーサイトを出発原料として製造されている。By the way, there are two main methods for producing goethite: a method in which the reaction is carried out on the acidic side (acidic method) and a method in which the reaction is carried out on the alkaline side (alkaline method). A portion of the iron content is precipitated into ferrous hydroxide by adding an alkali in an amount equal to or less than the amount of iron salt, and then an oxygen-containing gas such as air is introduced into this suspension to precipitate ferrous hydroxide. This is a method in which substantially all of the iron is oxidized to form goethite, and if necessary, remaining ferrous ions are further oxidized by adding alkali to convert them into goethite to obtain the desired particle r&length. As is well known, in the goethitization reaction, the suspension containing the ferrous hydroxide precipitate is generally transformed into a green rust (green rust) as the oxidation progresses. (commonly denoted as Fe0-nFe2O, .llllH2O)
When the oxidation rate reaches approximately 20 to 65%, the precipitation of ferrous hydroxide almost disappears, and the production and accumulation of green rust increases, and the p)l of vaginal fluid is 6.5.
It drops rapidly from ~8.5 to 5-6. (first*p
11 Inflection Point) Then, as oxidation continues, the vaginal fluid turns green, and the generation and growth of nucleus crystals progresses, converting into needle-shaped goethite (yellow), and the oxidation almost ends. The pi of vaginal fluid drops relatively quickly to 3-4. (Second pH inflection point) However, when producing goethite using the acidic method, so-called branched crystals that are branched in a dendritic manner are more likely to occur than in the case of the alkaline method, and also during the growth reaction. On the one hand, it is not easy to obtain particles with a uniform shape and a narrow particle size distribution because nucleation occurs easily, but on the other hand, most of the magnetic powders for magnetic recording media are acidic because the production cost is relatively low and it is industrially advantageous. It is manufactured using acicular goethite produced by a method as a starting material.
ところでＯｊｊ記酸性法におけるゲーサイト針状晶粒子
の製造において、前記粒径、粒子形状、粒度分布等の改
良を図るべく添加剤や酸化反応条件あるいは中和反応条
件等の検討については、すでに数多くの提案がなされて
いる。例えば、水溶性リン酸塩や水溶性ケイ酸塩などの
存在下で水酸化第一鉄の沈殿析出と酸化をおこなったり
、あるいは亜鉛化合物やニッケル化合物などの存在下に
酸化をおこなったり、さらには低温度で系外で酸化反応
させて微細な種晶を作りこれを系内に加えて引続き反応
させてゲーサイトを結晶成長させたりする方法が知られ
ている。しかしながら、これらの方法によって得られる
ゲーサイトは、微細結晶粒子を得るには十分でなかった
り、また必ずしも粒度分布巾が狭く形状性の良好なもの
が得られなかったりし、これを原料として製造される磁
性粉末及びそれを使用した磁気記録媒体は、未だ高記録
密度化及び高Ｓ／Ｎ比化に十分満足すべきものでない。By the way, in the production of goethite acicular crystal particles using the Ojj acid method, many studies have already been made regarding additives, oxidation reaction conditions, neutralization reaction conditions, etc. in order to improve the particle size, particle shape, particle size distribution, etc. proposals have been made. For example, precipitation and oxidation of ferrous hydroxide may be carried out in the presence of water-soluble phosphates or water-soluble silicates, or oxidation may be carried out in the presence of zinc compounds, nickel compounds, etc. A known method is to perform an oxidation reaction outside the system at a low temperature to produce fine seed crystals, add these to the system, and continue the reaction to grow crystals of goethite. However, the goethite obtained by these methods is not sufficient to obtain fine crystal grains, and it is not always possible to obtain products with a narrow particle size distribution and good shape. The magnetic powder and the magnetic recording medium using the same are not yet fully satisfactory in achieving high recording density and high S/N ratio.
なお、ゲーサイトの微細結晶化を図るには、例えば、反
応液の強力な攪拌下に水酸化第一鉄の細かい粒子を均一
に分散させるとともに、酸素含有ガスの導入速度を大巾
に増大させてやることも有効であるが、エネルギーコス
トが大と（なったり、また反応系を大型化する場合のス
ケールアップが容易でなかったりする。また、反応を比
較的低温下でおこなうことも有効であるが、反応時間が
大巾ｌこ長くなるとともに粒度分布が不揃し・になり易
かったりするなどの問題がさけられない。In addition, in order to achieve fine crystallization of goethite, for example, fine particles of ferrous hydroxide are uniformly dispersed under strong stirring of the reaction solution, and the introduction rate of oxygen-containing gas is greatly increased. It is also effective to carry out the reaction at a relatively low temperature, but this results in high energy costs and difficulty in scaling up the reaction system. However, there are unavoidable problems such as the reaction time becoming considerably longer and the particle size distribution becoming more likely to become uneven.
本発明者等は、かねてより前記ゲーサイト化反応におけ
る粒度コントロールの安定した操作条件を確立すべく種
々検討を進めた結果、意外にも当該酸化反応が特定の酸
化率範囲にまで進んだ段階の反応系に特定の処理剤を系
外から加えることによって、核晶の生成、成長を効果的
に誘起し、きわめて効率よく微細で形状性の良好な均一
粒度のゲーサイト針状晶を容易に得られることの知見を
得、本発明を完成したものである。The present inventors have carried out various studies for some time in order to establish stable operating conditions for particle size control in the goethitization reaction, and as a result, they unexpectedly found that when the oxidation reaction has progressed to a specific oxidation rate range, By adding a specific treatment agent to the reaction system from outside the system, it is possible to effectively induce the generation and growth of nucleus crystals, and easily obtain fine goethite needle crystals with uniform particle size and good shape in an extremely efficient manner. The present invention was completed based on this knowledge.
［発明の目的１
本発明は、主として磁気記録媒体として高記録密度化、
高Ｓ／Ｎ比化を満足し得るような磁性粉を製造する出発
原料として好適なゲーサイト針状晶粒子を工業的実施容
易な方法で効率よく製造する方法を提供することにある
。[Objective of the Invention 1] The present invention mainly aims at increasing recording density as a magnetic recording medium.
It is an object of the present invention to provide a method for efficiently producing goethite acicular crystal particles, which are suitable as a starting material for producing magnetic powder that can satisfy a high S/N ratio, by a method that is easy to implement industrially.
［発明の溝成１
本発明によるゲーサイトの製造方法は、第一鉄水溶液に
第一鉄塩に対して当量以下のアルカリを作用させて鉄分
の一部を水酸化第一鉄として沈殿させた懸濁液を得、次
いで該懸濁液を酸化してゲーサイトを製造するに当り、
該懸濁液に酸化開始後酸化率が２０〜６５％に達した段
階で酸性物質を添加することを特徴とする。[Measures of the Invention 1] The method for producing goethite according to the present invention includes treating a ferrous aqueous solution with an alkali in an amount equal to or less than the ferrous salt to precipitate part of the iron content as ferrous hydroxide. In obtaining a suspension and then oxidizing the suspension to produce goethite,
The method is characterized in that an acidic substance is added to the suspension at a stage when the oxidation rate reaches 20 to 65% after the start of oxidation.
本発明方法において、使用する第一鉄塩水溶液としては
、硫酸第一鉄、塩化第一鉄、硝酸第一鉄などの種々の鉱
酸の第一鉄塩溶液を使用し得るが、工業的には硫酸第一
鉄水溶液が好ましい。また、使用するアルカリとしては
、水酸化ナトリウム、水酸化カリウム、酸化ナトリウム
、炭酸ナトリウム、炭酸カルシウム、アンモニアなどが
挙げられるが、工業的には水酸化ナトリウム、炭酸ナト
リウム、水酸化カリウム、アンモニアなどの水溶液やア
ンモニアガスが好ましい。アルカリの添加量は、第一鉄
塩に対して当量以下好ましくは、０．０５〜０．８当量
であり、この部分中和は、Ｆｅ濃度が通常３０〜１００
ｇ／１２である原料の第一鉄塩水溶液を１０〜８０°Ｃ
好ましくは３０〜６０℃に加熱した後攪拌下添加するこ
とによって水酸化第一鉄を沈殿させ、ｐｔｌはぼ６〜８
でＦｅとして５〜５５ｇ／ρ水酸化第一鉄の懸濁液を得
る。次いで前記部分中和によって生成した水酸化第一鉄
を酸化するには、前記懸濁液に攪拌上酸化剤例えば、酸
素ガス、空気などの酸素含有ガスを導入することによっ
ておこなうことができる。酸素含有ガスの導入は通常懸
濁液ＩＱ当り０．１〜１０Ｑ／分が適当である。また、
酸化反応温度は１０〜８０°Ｃ１好ましくは３０〜６０
°Ｃであって、８０℃を越えるとマグネタイト結晶が生
成し易くなり、また前記範囲より低きにすぎると反応に
長時間を要するとともに粒度分布中が広くなり易く望し
くない。In the method of the present invention, ferrous salt solutions of various mineral acids such as ferrous sulfate, ferrous chloride, and ferrous nitrate can be used as the ferrous salt aqueous solution. is preferably an aqueous ferrous sulfate solution. In addition, the alkalis used include sodium hydroxide, potassium hydroxide, sodium oxide, sodium carbonate, calcium carbonate, ammonia, etc., but industrially, sodium hydroxide, sodium carbonate, potassium hydroxide, ammonia, etc. Aqueous solutions and ammonia gas are preferred. The amount of alkali added is preferably 0.05 to 0.8 equivalent to the ferrous salt, and this partial neutralization is carried out when the Fe concentration is usually 30 to 100.
A ferrous salt aqueous solution of the raw material with a concentration of g/12 is heated at 10 to 80°C.
Preferably, ferrous hydroxide is precipitated by heating to 30-60°C and adding under stirring, with a PTL of about 6-8.
A suspension of 5 to 55 g/ρ of ferrous hydroxide as Fe is obtained. Next, the ferrous hydroxide produced by the partial neutralization can be oxidized by stirring the suspension and introducing an oxidizing agent such as an oxygen-containing gas such as oxygen gas or air into the suspension. The oxygen-containing gas is normally introduced at a rate of 0.1 to 10 Q/min per IQ of suspension. Also,
The oxidation reaction temperature is 10 to 80°C, preferably 30 to 60°C.
If the temperature exceeds 80°C, magnetite crystals tend to form, and if the temperature is too low than the above range, the reaction takes a long time and the particle size distribution tends to become broad, which is undesirable.
本発明方法において、使用する酸性物質としては、種々
の無機酸または有機酸を使用し得るが、例えば塩酸、硫
酸、硝酸、弗酸、炭酸、リン酸等の無機酸、蟻酸、酢酸
、蓚酸、マレイン酸、７タル酸等のカルボン酸、クエン
酸、酒石酸、乳酸、グリコール酸等のオキシカルボン酸
、アスパラギン酸、アミノ酸などを挙げることができ、
工業的には塩酸、硫酸、酢酸を使用するのが有利である
。これらは単独で使用してもあるいは混用してもよく、
通常水溶液として添加する。In the method of the present invention, various inorganic or organic acids can be used as the acidic substance, such as inorganic acids such as hydrochloric acid, sulfuric acid, nitric acid, hydrofluoric acid, carbonic acid, phosphoric acid, formic acid, acetic acid, oxalic acid, Examples include carboxylic acids such as maleic acid and heptalacid, oxycarboxylic acids such as citric acid, tartaric acid, lactic acid, and glycolic acid, aspartic acid, and amino acids.
Industrially it is advantageous to use hydrochloric acid, sulfuric acid and acetic acid. These may be used alone or in combination,
Usually added as an aqueous solution.
前記酸性物質の添加量は、部分中和された第一鉄量基準
で０．１〜１０モル％、好ましくは０．５〜５モル％で
ある。The amount of the acidic substance added is 0.1 to 10 mol%, preferably 0.5 to 5 mol%, based on the amount of partially neutralized ferrous iron.
添加量が前記範囲より少なきにすぎると本発明の所望の
効果がもたらされず、また、添加量を前記範囲より多く
しても経済的に有利でない。If the amount added is too small than the above range, the desired effect of the present invention will not be achieved, and if the amount added is too much above the range, it will not be economically advantageous.
前記酸性物質の添加時期は、該懸濁液中の水酸化第一鉄
沈殿の酸化率が２０〜６５％、好ましくは３０〜５５％
の範囲に至る段階でおこなうのが好適である。すなわち
第一鉄塩水溶液を部分中和して得られた水酸化第一鉄沈
殿を含有する懸濁液に、酸素含有ガス等の酸化剤を導入
して酸化開始後酸化時間の経過につれて懸濁液は、青白
色から濃青色へと変化するとともにこの間該液のｐｌ＋
は６．５〜８．５ぐらいから徐々に低下し酸化率がほぼ
２０〜６５％の範囲において６．５〜８．５ぐらいから
ほぼ５〜６にまで急速に低下する領域（第一次ｐＨ屈曲
点域）であり、とりわけ当該酸性物質の添加時期が前記
ｐＨ屈曲点に極く近傍の領域に対応せる酸化率にある場
合には本発明の効果をより一層高めることができる。本
発明において酸性物質の添加時期は、反応系の酸化率が
前記範囲に到らない段階であっても、また前記範囲を過
ぎなる段階であっても本発明の所望の効果をもたらすこ
とができない。前記酸性物質を添加後反応系は、引続き
酸素含有ガス等の酸化剤を導入しつつ反応を継続して曲
記水酸化第−鉄沈殿の実質的全部をゲーサイトに転換す
る、それにともなって反応系の液ｐＨはほぼ３〜４にま
で低下し、長軸長がほぼ０．２５μ以下、軸比はぼ１５
〜２０、比表面積（ＢＥＴ法）はぼ８０−１５０ｍ２／
ｇを有する微細で形状の整った針状晶ゲーサイトが得ら
れる。The acidic substance is added at a time when the oxidation rate of the ferrous hydroxide precipitate in the suspension is 20 to 65%, preferably 30 to 55%.
It is preferable to carry out this process at the stage when the range reaches . That is, an oxidizing agent such as an oxygen-containing gas is introduced into a suspension containing a ferrous hydroxide precipitate obtained by partially neutralizing an aqueous ferrous salt solution, and after the oxidation starts, the suspension becomes suspended as the oxidation time elapses. The liquid changes from blue-white to dark blue, and during this time the liquid's pl+
The pH gradually decreases from about 6.5 to 8.5, and rapidly decreases from about 6.5 to 8.5 to about 5 to 6 when the oxidation rate is approximately 20 to 65% (primary pH In particular, when the acidic substance is added at an oxidation rate corresponding to a region very close to the pH inflection point, the effects of the present invention can be further enhanced. In the present invention, the desired effect of the present invention cannot be achieved even when the acidic substance is added at a stage where the oxidation rate of the reaction system does not reach the above range, or even at a stage where the oxidation rate exceeds the above range. . After adding the acidic substance, the reaction system continues the reaction while continuously introducing an oxidizing agent such as an oxygen-containing gas to convert substantially all of the ferric hydroxide precipitate into goethite. The pH of the liquid in the system decreased to approximately 3 to 4, the major axis length was approximately 0.25μ or less, and the axial ratio was approximately 15.
~20, specific surface area (BET method) is approximately 80-150m2/
Fine and well-shaped acicular goethite having a fine and uniform shape is obtained.
前記のようにして得られた針状晶ゲーサイトを懸濁し、
かつ第一鉄塩を含有した反応処理液を通常の濾過、水洗
、乾燥を経てゲーサイト粉末として回収するか、あるい
は必要に応じ前記反応処理液へさらにアルカリを添加し
ながら酸化して前記針状晶ゲーサイト粒子を核晶として
所望の粒径まで成長させてから濾過、水洗、乾燥を径で
ゲーサイト粉末として回収することもできる。Suspending the acicular goethite obtained as described above,
The reaction solution containing the ferrous salt can be recovered as a goethite powder through conventional filtration, water washing, and drying, or it can be oxidized while adding an alkali to the reaction solution to form the acicular shape. It is also possible to grow crystalline goethite particles as nucleus crystals to a desired particle size, then filter, wash with water, and dry to recover the size as goethite powder.
前記のようにして得られた本発明方法に係わるゲーサイ
ト粉末は、常法により、例えば、３００〜７００ ”Ｃ
で加熱脱水してα−Ｆｅ２０つとし、次いで水素または
水蒸気を含む水素ガス中で３００〜５００℃で還元して
Ｆ ｅ ｉ Ｏ４とし、さらに酸素または酸素含有ガス
中で２００〜４００ ”Ｃで酸化することによってγ−
Ｆｅ２ｏ、系の磁性酸化鉄粉としたり、あるいは水素ま
たは水蒸気を含む水素ガス中で３５０〜４５０℃で還元
したり、もしくは脂肪酸等の有機物存在下で３００〜５
００°Ｃで還元したりして磁性粉末を製造することがで
きる。かくして得られた磁性粉末は、ゲーサイト針状晶
形状を保持した粒度分布のシャープな微細粒子であって
磁気記録媒体における分散性、磁場配向性、充填性に優
れており、高記録密度化、高Ｓ／Ｎ比高出力化を達成す
る上できわめて好ましいものである。なお、本発方法に
よれば微小粒子径のゲーサイトが容易に得られるため前
記磁性粉末製造用の原料のほか、例えば透明性酸化鉄顔
料製造用の原料としても好適なものである。The goethite powder according to the method of the present invention obtained as described above can be heated to a temperature of, for example, 300 to 700"
It is heated and dehydrated to obtain 20 α-Fe, then reduced in hydrogen or hydrogen gas containing water vapor at 300 to 500°C to obtain Fe i O4, and further oxidized in oxygen or oxygen-containing gas at 200 to 400”C. By doing γ−
Fe2O, as a magnetic iron oxide powder, or reduced at 350 to 450°C in hydrogen or hydrogen gas containing water vapor, or in the presence of organic substances such as fatty acids to 300 to 5
Magnetic powder can be produced by reduction at 00°C. The magnetic powder thus obtained is fine particles with a sharp particle size distribution that maintains the shape of goethite needle crystals, and has excellent dispersibility, magnetic field orientation, and filling properties in magnetic recording media, and is useful for high recording density, This is extremely preferable in achieving a high S/N ratio and high output. Furthermore, according to the method of the present invention, goethite with a fine particle size can be easily obtained, so that it is suitable not only as a raw material for producing the magnetic powder but also, for example, as a raw material for producing transparent iron oxide pigments.
［発明の効果］
本発明によれば、主として磁気記録用磁性粉末製造の出
発原料として好適な粒度分布のシャープで枝分れが少な
く、かつ良好な軸比を有する微細な粒径のゲーサイト針
状晶粒子を工業的実施が容易な手段できわめて効率よく
得ることができるものであり、また、本発明による場合
は前記の如く、ゲーサイトの微細粒子を容易に得られる
ところから、これを核晶として高成長倍率で所望粒子径
に成長させることができ、第一鉄塩水溶液の装着容量当
りのゲーサイト製造量を大きくすることができるなど、
その工業的意義は極めて大きい。[Effects of the Invention] According to the present invention, goethite needles with a fine particle size having a sharp particle size distribution, less branching, and a good axial ratio, which are suitable as a starting material for producing magnetic powder for magnetic recording, are produced. In the case of the present invention, as described above, fine particles of goethite can be easily obtained, so that they can be obtained by nucleating them. As a crystal, it can be grown to a desired particle size at a high growth rate, and the amount of goethite produced per capacity of ferrous salt aqueous solution can be increased.
Its industrial significance is extremely large.
以下に実施例及び比較例を挙げて本発明をさらに説明す
る。The present invention will be further explained by giving examples and comparative examples below.
実施例１
硫酸第一鉄水品を水に溶解したＦｅ濃度”ａｏｇ／（ｌ
の硫酸第一鉄水；容ｉ２５θを空気１次込み管と攪拌磯
を備えた反応器に入れ、５０ ”Ｃに昇温し、ここへ攪
拌下水酸化ナトリウム水溶液（濃度４００ｇ／θ）、１
．６０（第一鉄塩に対して０．２２５当量）を徐々に加
えて部分中和し水酸化第一鉄沈殿（Ｆｅとして１８ｇ／
ρ）を含む懸濁液（ｐＨ６，６）を得た。次いで該懸濁
液へ、攪拌下１０ρ／分の速度で空気吹込みをおこなっ
て酸化反応を進め、該懸濁液中の水酸化第一鉄沈殿の酸
化率が４２％になった段階で（酸化反応開始後２１分、
液ｐＨ５で、液の色は）農青色、第１図のｐＨ曲線にお
けるＡ点）、酸性物質として塩酸（濃度２０重量％）を
１３．２ｍρ（１モル％）加えた。しかる後引続き酸化
反応を４０分間おこなってゲーサイト針状結晶を生成さ
せた。なお、前記酸化反応終了時の液ｐｌ＋はほぼ３、
Ｆｅ２＋濃度は５８ｇ／ｆｆであり、また沈殿の酸化率
はほぼ１００％であった。Example 1 Fe concentration "aog/(l) of ferrous sulfate solution dissolved in water"
Aqueous ferrous sulfate with a volume of i25θ was placed in a reactor equipped with a primary air inlet and a stirring rock, heated to 50"C, and aqueous sodium hydroxide solution (concentration 400g/θ), 1
．． 60 (0.225 equivalents relative to ferrous salt) was gradually added to partially neutralize and precipitate ferrous hydroxide (18 g/Fe as Fe).
A suspension (pH 6.6) containing ρ) was obtained. Next, air was blown into the suspension at a rate of 10 ρ/min while stirring to advance the oxidation reaction, and when the oxidation rate of the ferrous hydroxide precipitate in the suspension reached 42% ( 21 minutes after the start of the oxidation reaction,
The pH of the solution was 5, the color of the solution was agricultural blue (point A on the pH curve in FIG. 1), and 13.2 mρ (1 mol %) of hydrochloric acid (concentration 20% by weight) was added as an acidic substance. Thereafter, an oxidation reaction was continued for 40 minutes to produce goethite needle crystals. In addition, the liquid pl+ at the end of the oxidation reaction is approximately 3,
The Fe2+ concentration was 58 g/ff, and the oxidation rate of the precipitate was approximately 100%.
上記反応により得られたゲーサイト針状結晶スラリーは
、濾過、水洗、乾燥をおこなって試料Ａとした。このも
のについて常法により平均長軸長しくμ）、軸比（Ｌ／
Ｗ＞、ＢＥＴ法により比表面積（Ｓｇ）、さらに下記の
方法により粒度分布（σＬ／Ｌ）について測定した。The goethite needle crystal slurry obtained by the above reaction was filtered, washed with water, and dried to obtain Sample A. For this item, the average major axis length (μ) and axial ratio (L/
W>, the specific surface area (Sg) was measured by the BET method, and the particle size distribution (σL/L) was measured by the method described below.
粒度分布（σＬ／Ｌ）の測定方法
よく分散させたゲーサイトを試料とし、電子顕微鏡によ
り１０００個の粒子の長袖粒子径を読みとり、その算術
平均軸長しくμ）と標準偏差σＬ（μ）を決め、次式に
したがって粒度分布を求める。Method for measuring particle size distribution (σL/L) Using well-dispersed goethite as a sample, read the long-sleeved particle diameter of 1000 particles using an electron microscope, and calculate the arithmetic mean axis length (μ) and standard deviation σL (μ). and determine the particle size distribution according to the following formula.
粒度分布 ＝ σＬ／Ｌ
なお、本明細書において酸化率とは、反応系における水
酸化第一鉄沈殿の酸化率ｍ（％）を意味し、次式によっ
て表わされるものである。Particle size distribution = σL/L In this specification, the oxidation rate means the oxidation rate m (%) of the ferrous hydroxide precipitate in the reaction system, and is expressed by the following formula.
実施例２
実施例１において、酸性物質として硫酸（濃度２４．９
重量％）を１２．９ｍｆｆ （０，５モル％）加えたこ
と以外は同例の場合と同様に処理した。（試料Ｂ）
実施例３
実施例１において、酸性物質として硝酸（濃度３１．６
重量％）を１３．４ｎ＋ｆｆ（１モル％）加えたこと以
外は同例の場合と同様に処理した。（試料Ｃ）
実施例４
実施例１において、酸性物質としてオルトリン酸（濃度
１７．８重量％）を１３．４ｍ１２ （０，３３モル％
）加えたこと以外は、同例の場合と同様に処理した。（
試料Ｄ）実施例５
実施例１において、酸性物質として酢酸（濃度３４．５
重量％）を１３．４ｍρ（１モル％）加えたこと以外は
同例の場合と同様に処理した。（試料Ｅ）
実施例６
実施例１において、反応母液の硫酸第一鉄水溶液にオル
トリン酸ナトリウム（濃度１７．８重量％）を１３．４
ｍρ（０，３３モル％）加え、次いで同例の場合と同様
にして中和、酸化をおこなった。（試料Ｆ）
実施例７
実施例１において、酸性物質として塩酸（濃度２０．０
重量％）を３９．６ｍＱ（３モル％）加えたことのほか
は同例の場合と同様に処理した。（試料Ｇ）
実施例８
実施例２において、硫酸の添加を酸化率が３０％となっ
た段階（酸化反応開始後１５分、懸濁液のｐＨ６，３，
１５１図のｐＨ曲線におけるＢ点）でおこなうほかは同
例の場合と同様に処理した。（試料Ｈ）
実施例９
実施例２において、硫酸の添加を酸化率が５１％となっ
た段階（酸化反応開始後３０分、懸濁液のｐＨ５，２、
第１図のｐ１１曲線における０点）でおこなうほかは同
例の場合と同様に処理した。（試料Ｉ）
実施例１０
実施例７で得られたゲーサイト針状結晶スラリー（Ｆｅ
”濃度５８ ｇ／（１）を６０°Ｃまで昇温し、攪拌下
２ρ／分の速度で空気を吹込みながら水酸化ナトリウム
水溶液（濃度４００ｇ／Ｑ）１．６ｇを徐々に加えて１
）１１を４．３に維持し、５時間反応させて前記ゲーサ
イト針状晶をほぼ２倍（重量基準）に成長させた。（試
料Ｇ）
比較例１
実施例１において、酸性物質の添加をおこなわないこと
のほかは同例の場合と同様に処理した。（試料Ｊ）比較
例２
実施例１において、酸性物質の添加を酸化率が１５％に
なった段階（酸化反応開始後８分、懸濁液のｐＨ６，４
で液の色は濃青色、第１図のｐＨ曲線におけるＤ点）で
おこなうことのほかは同例の場合と同様に処理した。（
試料Ｋ）比較例３
実施例１において、酸性物質の添加を酸化率が６８％に
なった段階（酸化反応開始後３８分、懸濁液のｐＨ５，
１で液の色は緑色、第１図のｐＨ曲線におけるＥ点）で
おこなうことのほかは同例の場合と同様に処理した。（
試料Ｌ）比較例４
実施例１において、塩酸に代えて塩化ナトリウム水溶液
（濃度３５．１ｇ／Ｑ）１３．４ｎ＋Ｉ２ （１モル％
）を、添加することのほかは、同例の場合と同様に処理
した。（試料Ｍ）比較例５
実施例２において、硫酸に代えて硫酸ナトリウム水溶液
（濃度４２．７ｇ／ＲＨ３，４ｍａ （０，５モル％）
を、添加することのほかは、同例の場合と同様に処理し
た。（試料Ｎ）比較例６
実施例６において、酸化反応時に塩酸の添加をおこなわ
ないことのほかは、同例の場合と同様に処理した。（試
料Ｐ）なお、前記の実施例及び比較例において酸性物質
の添加モル％は、原料として使用する第一鉄塩量基準に
対する値である。Example 2 In Example 1, sulfuric acid (concentration 24.9
The process was carried out in the same manner as in the same example except that 12.9 mff (0.5 mol %) of 12.9 mff (% by weight) was added. (Sample B) Example 3 In Example 1, nitric acid (concentration 31.6
The process was carried out in the same manner as in the same example except that 13.4n+ff (1 mol%) of 13.4n+ff (1% by weight) was added. (Sample C) Example 4 In Example 1, 13.4 m12 (0.33 mol%) of orthophosphoric acid (concentration 17.8% by weight) was used as the acidic substance.
) was processed in the same manner as in the same example. (
Sample D) Example 5 In Example 1, acetic acid (concentration 34.5
The process was carried out in the same manner as in the same example except that 13.4 mρ (1 mol %) of 13.4 mρ (1 mol %) was added. (Sample E) Example 6 In Example 1, 13.4% of sodium orthophosphate (concentration 17.8% by weight) was added to the ferrous sulfate aqueous solution as the reaction mother liquor.
mρ (0.33 mol %) was added, and then neutralization and oxidation were performed in the same manner as in the same example. (Sample F) Example 7 In Example 1, hydrochloric acid (concentration 20.0
The process was carried out in the same manner as in the same example, except that 39.6 mQ (3 mol %) of 39.6 mQ (3 mol %) was added. (Sample G) Example 8 In Example 2, sulfuric acid was added at a stage when the oxidation rate reached 30% (15 minutes after the start of the oxidation reaction, the pH of the suspension was 6.3,
The treatment was carried out in the same manner as in the same example except that it was carried out at point B in the pH curve in Figure 151. (Sample H) Example 9 In Example 2, sulfuric acid was added at the stage when the oxidation rate reached 51% (30 minutes after the start of the oxidation reaction, the pH of the suspension was 5.2,
The processing was carried out in the same manner as in the case of the same example except that the processing was carried out at point 0 on the p11 curve in FIG. (Sample I) Example 10 Goethite needle crystal slurry (Fe
"Concentration 58 g/(1) was heated to 60°C, and 1.6 g of sodium hydroxide aqueous solution (concentration 400 g/Q) was gradually added while stirring and blowing air at a rate of 2 ρ/min.
) 11 was maintained at 4.3, the reaction was carried out for 5 hours, and the goethite needle crystals were grown approximately twice as much (on a weight basis). (Sample G) Comparative Example 1 A sample was treated in the same manner as in Example 1 except that no acidic substance was added. (Sample J) Comparative Example 2 In Example 1, the acidic substance was added at a stage when the oxidation rate reached 15% (8 minutes after the start of the oxidation reaction, the pH of the suspension was 6.4
The solution was treated in the same manner as in the same example except that the color of the solution was dark blue and the treatment was carried out at point D on the pH curve in Figure 1). (
Sample K) Comparative Example 3 In Example 1, the acidic substance was added at a stage when the oxidation rate reached 68% (38 minutes after the start of the oxidation reaction, the pH of the suspension was 5,
1, the color of the liquid was green, and the treatment was carried out in the same manner as in the case of the same example, except that it was carried out at point E on the pH curve in Fig. 1). (
Sample L) Comparative Example 4 In Example 1, aqueous sodium chloride solution (concentration 35.1 g/Q) 13.4n+I2 (1 mol%
) was treated in the same manner as in the same example except that . (Sample M) Comparative Example 5 In Example 2, sodium sulfate aqueous solution (concentration 42.7 g/RH3.4 ma (0.5 mol%)
The treatment was carried out in the same manner as in the same example except that . (Sample N) Comparative Example 6 The same treatment as in Example 6 was carried out except that hydrochloric acid was not added during the oxidation reaction. (Sample P) In the above Examples and Comparative Examples, the molar percentage of the acidic substance added is a value based on the amount of ferrous salt used as a raw material.
前記の実施例及び比較例で得られた各試料粉末について
の特性を表１に示す。Table 1 shows the characteristics of each sample powder obtained in the above Examples and Comparative Examples.
表１の結果からみられるように、本発明方法に従って得
られるゲーサイト粒子は、微細で軸比の優れたかつ粒度
分布のシャープな針状性の良好なものであり、またこの
優れた粒子形状性及び粒度分布特性を損なうことなくさ
らに所望の粒子径に容易に成長し得るものである。一方
、比較例の場合は、いづれも本発明のものに及ばないこ
とがわかる。As can be seen from the results in Table 1, the goethite particles obtained according to the method of the present invention are fine, have an excellent axial ratio, have a sharp particle size distribution, and have good acicularity. Furthermore, the particles can be easily grown to a desired particle size without impairing the particle size distribution characteristics. On the other hand, it can be seen that all of the comparative examples are inferior to those of the present invention.
前記実施例にて得られた試料Ａ、Ｊ及び比較例の試料Ｋ
、Ｌ、Ｐ、Ｑの各ゲーサイトに対して、リン化合物（Ｐ
２Ｏ３として０．６９重量％）及びケイ素化合物（Ｓｉ
Ｏ２として０．２１重量％）を被覆処理した後大気中で
６００°Ｃにて脱水し、次いで水素気流中３７０℃で還
元してＦｅ＋０４とし、しかる後大気中２００’Ｃで再
酸化してγ−Ｆｅ、０３粉末を得た。得られた各７−Ｆ
ｅ２Ｏ３粉末についてＢＥＴ法比面積Ｓ ｇ（ｍ２／ｇ
）、振動試料型磁力計にて保磁カニＨｃ（Ｏｅ）、飽和
磁化：σｓ（ｅｍｕ／ｇ）、角型比：Ｒ５を測定した。Samples A and J obtained in the above examples and sample K of the comparative example
, L, P, and Q goethite, a phosphorus compound (P
0.69% by weight as 2O3) and silicon compounds (Si
After coating with 0.21% by weight as O2), it was dehydrated at 600°C in the air, then reduced at 370°C in a hydrogen stream to give Fe+04, and then reoxidized at 200°C in the air to give γ -Fe,03 powder was obtained. Each 7-F obtained
BET method specific area S g (m2/g
), coercion crab Hc (Oe), saturation magnetization: σs (emu/g), and squareness ratio: R5 were measured using a vibrating sample magnetometer.
それらの結果を表２に示す。The results are shown in Table 2.
表２
発 Ａ ５２ ３４１ ７１
０．４４明 Ｊ ５４ ３３８
７０ ０，４２Ｋ ４１ ３１０ ７１
０．４４比 Ｌ ３７ ３２０ ７
２ ０，４３較 Ｐ ３８ ３０８
７０ ０．４２Ｑ ４０ ３０５ ７０
０．４３表２の結果から明らかなように、本発明の方
法によって得られるゲーサイトより導かれるγ−Ｆｅ２
０．磁性粉末は、微細粒子径のものであってかっこのも
のの保磁力は優れており高い形状異方性のものであるこ
とがわかる。Table 2 From A 52 341 71
0.44 light J 54 338
70 0,42K 41 310 71
0.44 ratio L 37 320 7
2 0,43 comparison P 38 308
70 0.42Q 40 305 70
0.43 As is clear from the results in Table 2, γ-Fe2 derived from goethite obtained by the method of the present invention
0. It can be seen that the magnetic powder has a fine particle size, and the one in parentheses has an excellent coercive force and a high shape anisotropy.
また前記実施例にて得られた試料Ａ、Ｊ及び比較例の試
料に、Ｌ、Ｐの各ゲーサイトに対して、アルミ化合物（
Ａｆｆ２０． として０．７重量％）及ヒケイ素化合物
（Ｓｉｎ２として０．４重量％）を被覆処理した後大気
中で７００℃にて脱水し、次いで水素気流中４２０°Ｃ
で還元して金属鉄粉末を得た。得られた金属鉄粉末につ
いて前記γ−Ｆｅ２０゜の場合と同様の方法で特性を測
定した。それらの結果を表３に示す。In addition, aluminum compounds (
Aff20. After coating with 0.7% by weight as Sin2) and an arsenic compound (0.4% by weight as Sin2), dehydration was performed at 700°C in the air, and then at 420°C in a hydrogen stream.
was reduced to obtain metallic iron powder. The properties of the obtained metallic iron powder were measured in the same manner as in the case of γ-Fe20°. The results are shown in Table 3.
表３
発 Ａ ４５ １４５０ １４１
０．５１明 Ｊ ４６ １４２０
１４３ ０．５０比 Ｋ ３８ １
２７０ １４０ ０，４６Ｌ ３４１３００１３
９０．４４
較 Ｐ ３２ １１００ １３７ ０
．４２表３の結果から明らかなように、本発明の方法に
よって得られるゲーサイトより導かれる金属鉄磁性粉末
は、微細粒子径のものであってかつその磁気特性が優れ
たものであることがわかる。Table 3 Departure A 45 1450 141
0.51 light J 46 1420
143 0.50 ratio K 38 1
270 140 0,46L 34130013
90.44 Comparison P 32 1100 137 0
．． 42 As is clear from the results in Table 3, the metal iron magnetic powder derived from goethite obtained by the method of the present invention has a fine particle size and has excellent magnetic properties. .
第１図は、本発明の実施例、ならびに比較例における酸
化反応時の反応系のｌ）Ｈ変化の様子を例示した線図で
ある。
特許出願人 石原産業株式会社
第１図
酸化時間（分）FIG. 1 is a diagram illustrating the change in l)H in the reaction system during the oxidation reaction in Examples of the present invention and Comparative Examples. Patent applicant: Ishihara Sangyo Co., Ltd. Figure 1 Oxidation time (minutes)
Claims (1)
リを作用させて鉄分の一部を水酸化第一鉄として沈殿さ
せた懸濁液を得、次いで該懸濁液を酸化してゲーサイト
を製造するに当り、該懸濁液に酸化開始後酸化率が２０
〜６５％に達した段階で酸性物質を添加し、しかる後引
続き酸化反応をおこなうことを特徴とするゲーサイトの
製造方法。A suspension in which a portion of the iron is precipitated as ferrous hydroxide is obtained by reacting an aqueous solution of ferrous salt with an alkali in an amount equal to or less than the ferrous salt, and then oxidizing the suspension. In producing goethite, the suspension has an oxidation rate of 20 after the start of oxidation.
A method for producing goethite, characterized in that an acidic substance is added when the concentration reaches ~65%, and then an oxidation reaction is performed.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP61017027A JPH0611653B2 (en) | 1986-01-29 | 1986-01-29 | Method for manufacturing needle-shaped goethite for magnetic recording material |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP61017027A JPH0611653B2 (en) | 1986-01-29 | 1986-01-29 | Method for manufacturing needle-shaped goethite for magnetic recording material |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS62176923A true JPS62176923A (en) | 1987-08-03 |
| JPH0611653B2 JPH0611653B2 (en) | 1994-02-16 |
Family
ID=11932511
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP61017027A Expired - Lifetime JPH0611653B2 (en) | 1986-01-29 | 1986-01-29 | Method for manufacturing needle-shaped goethite for magnetic recording material |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0611653B2 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105819516A (en) * | 2016-05-17 | 2016-08-03 | 李可斌 | Preparation method of stable ferrous hydroxide |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS4942599A (en) * | 1972-08-30 | 1974-04-22 |
-
1986
- 1986-01-29 JP JP61017027A patent/JPH0611653B2/en not_active Expired - Lifetime
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS4942599A (en) * | 1972-08-30 | 1974-04-22 |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105819516A (en) * | 2016-05-17 | 2016-08-03 | 李可斌 | Preparation method of stable ferrous hydroxide |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0611653B2 (en) | 1994-02-16 |
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