JP2007070213A - Magnetite powder and method for producing the same - Google Patents
Magnetite powder and method for producing the same Download PDFInfo
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- SZVJSHCCFOBDDC-UHFFFAOYSA-N iron(II,III) oxide Inorganic materials O=[Fe]O[Fe]O[Fe]=O SZVJSHCCFOBDDC-UHFFFAOYSA-N 0.000 title claims abstract description 114
- 239000000843 powder Substances 0.000 title claims abstract description 86
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 13
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims abstract description 89
- 239000002245 particle Substances 0.000 claims abstract description 51
- 229910045601 alloy Inorganic materials 0.000 claims abstract description 48
- 239000000956 alloy Substances 0.000 claims abstract description 48
- 239000002253 acid Substances 0.000 claims abstract description 29
- 239000003513 alkali Substances 0.000 claims abstract description 11
- 239000000243 solution Substances 0.000 claims description 40
- 239000007787 solid Substances 0.000 claims description 28
- 229910017086 Fe-M Inorganic materials 0.000 claims description 22
- 238000010438 heat treatment Methods 0.000 claims description 21
- 239000012670 alkaline solution Substances 0.000 claims description 15
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims description 12
- 239000007789 gas Substances 0.000 claims description 12
- 229910052760 oxygen Inorganic materials 0.000 claims description 12
- 239000001301 oxygen Substances 0.000 claims description 12
- 229910052761 rare earth metal Inorganic materials 0.000 claims description 11
- 229910052742 iron Inorganic materials 0.000 claims description 10
- 239000012298 atmosphere Substances 0.000 claims description 8
- 229910052782 aluminium Inorganic materials 0.000 claims description 6
- 229910052751 metal Inorganic materials 0.000 claims description 6
- 229910052710 silicon Inorganic materials 0.000 claims description 6
- XLYOFNOQVPJJNP-UHFFFAOYSA-M hydroxide Chemical compound [OH-] XLYOFNOQVPJJNP-UHFFFAOYSA-M 0.000 claims description 5
- 229910052748 manganese Inorganic materials 0.000 claims description 5
- 229910052759 nickel Inorganic materials 0.000 claims description 4
- 229910052719 titanium Inorganic materials 0.000 claims description 4
- 229910052727 yttrium Inorganic materials 0.000 claims description 4
- 239000011343 solid material Substances 0.000 claims description 3
- 229910052692 Dysprosium Inorganic materials 0.000 claims description 2
- 229910052779 Neodymium Inorganic materials 0.000 claims description 2
- 229910052777 Praseodymium Inorganic materials 0.000 claims description 2
- 229910052771 Terbium Inorganic materials 0.000 claims description 2
- 230000001590 oxidative effect Effects 0.000 claims description 2
- FFBHFFJDDLITSX-UHFFFAOYSA-N benzyl N-[2-hydroxy-4-(3-oxomorpholin-4-yl)phenyl]carbamate Chemical compound OC1=C(NC(=O)OCC2=CC=CC=C2)C=CC(=C1)N1CCOCC1=O FFBHFFJDDLITSX-UHFFFAOYSA-N 0.000 claims 2
- 239000002994 raw material Substances 0.000 abstract description 13
- 229910000640 Fe alloy Inorganic materials 0.000 abstract 1
- 238000006243 chemical reaction Methods 0.000 description 32
- 239000007864 aqueous solution Substances 0.000 description 29
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 27
- 239000000203 mixture Substances 0.000 description 19
- 238000000034 method Methods 0.000 description 18
- KWYUFKZDYYNOTN-UHFFFAOYSA-M Potassium hydroxide Chemical compound [OH-].[K+] KWYUFKZDYYNOTN-UHFFFAOYSA-M 0.000 description 15
- 229910052595 hematite Inorganic materials 0.000 description 15
- 239000011019 hematite Substances 0.000 description 15
- LIKBJVNGSGBSGK-UHFFFAOYSA-N iron(3+);oxygen(2-) Chemical compound [O-2].[O-2].[O-2].[Fe+3].[Fe+3] LIKBJVNGSGBSGK-UHFFFAOYSA-N 0.000 description 15
- 238000002441 X-ray diffraction Methods 0.000 description 14
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 11
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 10
- 239000002002 slurry Substances 0.000 description 10
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 description 8
- 238000004458 analytical method Methods 0.000 description 8
- 229910017604 nitric acid Inorganic materials 0.000 description 8
- 230000035484 reaction time Effects 0.000 description 7
- WMFOQBRAJBCJND-UHFFFAOYSA-M Lithium hydroxide Chemical compound [Li+].[OH-] WMFOQBRAJBCJND-UHFFFAOYSA-M 0.000 description 6
- 239000006096 absorbing agent Substances 0.000 description 6
- 229910052783 alkali metal Inorganic materials 0.000 description 6
- 229910052796 boron Inorganic materials 0.000 description 6
- 230000008018 melting Effects 0.000 description 5
- 238000002844 melting Methods 0.000 description 5
- 239000002244 precipitate Substances 0.000 description 5
- 238000001228 spectrum Methods 0.000 description 5
- ATRRKUHOCOJYRX-UHFFFAOYSA-N Ammonium bicarbonate Chemical compound [NH4+].OC([O-])=O ATRRKUHOCOJYRX-UHFFFAOYSA-N 0.000 description 4
- KRHYYFGTRYWZRS-UHFFFAOYSA-N Fluorane Chemical compound F KRHYYFGTRYWZRS-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
- UIIMBOGNXHQVGW-UHFFFAOYSA-M Sodium bicarbonate Chemical compound [Na+].OC([O-])=O UIIMBOGNXHQVGW-UHFFFAOYSA-M 0.000 description 4
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 4
- -1 alkali metal salt Chemical class 0.000 description 4
- 239000001099 ammonium carbonate Substances 0.000 description 4
- 150000003863 ammonium salts Chemical class 0.000 description 4
- 229960004887 ferric hydroxide Drugs 0.000 description 4
- 150000004679 hydroxides Chemical class 0.000 description 4
- IEECXTSVVFWGSE-UHFFFAOYSA-M iron(3+);oxygen(2-);hydroxide Chemical compound [OH-].[O-2].[Fe+3] IEECXTSVVFWGSE-UHFFFAOYSA-M 0.000 description 4
- NCNCGGDMXMBVIA-UHFFFAOYSA-L iron(ii) hydroxide Chemical compound [OH-].[OH-].[Fe+2] NCNCGGDMXMBVIA-UHFFFAOYSA-L 0.000 description 4
- 239000002184 metal Substances 0.000 description 4
- 239000002689 soil Substances 0.000 description 4
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 3
- 238000004438 BET method Methods 0.000 description 3
- 229910001122 Mischmetal Inorganic materials 0.000 description 3
- 238000010521 absorption reaction Methods 0.000 description 3
- 238000007664 blowing Methods 0.000 description 3
- 229910052598 goethite Inorganic materials 0.000 description 3
- 238000000227 grinding Methods 0.000 description 3
- AEIXRCIKZIZYPM-UHFFFAOYSA-M hydroxy(oxo)iron Chemical compound [O][Fe]O AEIXRCIKZIZYPM-UHFFFAOYSA-M 0.000 description 3
- 150000002500 ions Chemical class 0.000 description 3
- 235000014413 iron hydroxide Nutrition 0.000 description 3
- 238000007561 laser diffraction method Methods 0.000 description 3
- 239000012266 salt solution Substances 0.000 description 3
- 239000003516 soil conditioner Substances 0.000 description 3
- 229910000013 Ammonium bicarbonate Inorganic materials 0.000 description 2
- NLXLAEXVIDQMFP-UHFFFAOYSA-N Ammonium chloride Substances [NH4+].[Cl-] NLXLAEXVIDQMFP-UHFFFAOYSA-N 0.000 description 2
- VHUUQVKOLVNVRT-UHFFFAOYSA-N Ammonium hydroxide Chemical compound [NH4+].[OH-] VHUUQVKOLVNVRT-UHFFFAOYSA-N 0.000 description 2
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-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
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 description 2
- ZLMJMSJWJFRBEC-UHFFFAOYSA-N Potassium Chemical compound [K] ZLMJMSJWJFRBEC-UHFFFAOYSA-N 0.000 description 2
- 150000001340 alkali metals Chemical class 0.000 description 2
- QGZKDVFQNNGYKY-UHFFFAOYSA-N ammonia Natural products N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 description 2
- 235000012538 ammonium bicarbonate Nutrition 0.000 description 2
- 235000012501 ammonium carbonate Nutrition 0.000 description 2
- 235000011114 ammonium hydroxide Nutrition 0.000 description 2
- 150000001450 anions Chemical class 0.000 description 2
- 239000012736 aqueous medium Substances 0.000 description 2
- 239000012300 argon atmosphere Substances 0.000 description 2
- 150000004649 carbonic acid derivatives Chemical class 0.000 description 2
- 238000005266 casting Methods 0.000 description 2
- 229910052802 copper Inorganic materials 0.000 description 2
- 238000010908 decantation Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 230000036571 hydration Effects 0.000 description 2
- 238000006703 hydration reaction Methods 0.000 description 2
- 239000001257 hydrogen Substances 0.000 description 2
- 229910052739 hydrogen Inorganic materials 0.000 description 2
- BAUYGSIQEAFULO-UHFFFAOYSA-L iron(2+) sulfate (anhydrous) Chemical compound [Fe+2].[O-]S([O-])(=O)=O BAUYGSIQEAFULO-UHFFFAOYSA-L 0.000 description 2
- 229910052744 lithium Inorganic materials 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 229910052757 nitrogen Inorganic materials 0.000 description 2
- 150000002896 organic halogen compounds Chemical class 0.000 description 2
- 230000035699 permeability Effects 0.000 description 2
- 229910052698 phosphorus Inorganic materials 0.000 description 2
- 229910052700 potassium Inorganic materials 0.000 description 2
- 239000011591 potassium Substances 0.000 description 2
- 238000012545 processing Methods 0.000 description 2
- 238000010298 pulverizing process Methods 0.000 description 2
- 150000003839 salts Chemical class 0.000 description 2
- 229910052708 sodium Inorganic materials 0.000 description 2
- 239000011734 sodium Substances 0.000 description 2
- 229910000030 sodium bicarbonate Inorganic materials 0.000 description 2
- 235000017557 sodium bicarbonate Nutrition 0.000 description 2
- 229910000029 sodium carbonate Inorganic materials 0.000 description 2
- 235000017550 sodium carbonate Nutrition 0.000 description 2
- 238000003756 stirring Methods 0.000 description 2
- 229910052717 sulfur Inorganic materials 0.000 description 2
- 239000002344 surface layer Substances 0.000 description 2
- 239000000725 suspension Substances 0.000 description 2
- BVKZGUZCCUSVTD-UHFFFAOYSA-L Carbonate Chemical compound [O-]C([O-])=O BVKZGUZCCUSVTD-UHFFFAOYSA-L 0.000 description 1
- VGGSQFUCUMXWEO-UHFFFAOYSA-N Ethene Chemical compound C=C VGGSQFUCUMXWEO-UHFFFAOYSA-N 0.000 description 1
- 239000005977 Ethylene Substances 0.000 description 1
- CYTYCFOTNPOANT-UHFFFAOYSA-N Perchloroethylene Chemical group ClC(Cl)=C(Cl)Cl CYTYCFOTNPOANT-UHFFFAOYSA-N 0.000 description 1
- 239000000654 additive Substances 0.000 description 1
- 230000000996 additive effect Effects 0.000 description 1
- 229910052784 alkaline earth metal Inorganic materials 0.000 description 1
- 150000001342 alkaline earth metals Chemical class 0.000 description 1
- 229910052791 calcium Inorganic materials 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 229910052804 chromium Inorganic materials 0.000 description 1
- 230000000052 comparative effect Effects 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 229910001873 dinitrogen Inorganic materials 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- 238000010828 elution Methods 0.000 description 1
- 238000011049 filling Methods 0.000 description 1
- 238000005194 fractionation Methods 0.000 description 1
- 229910052733 gallium Inorganic materials 0.000 description 1
- 229910052736 halogen Inorganic materials 0.000 description 1
- 150000002367 halogens Chemical class 0.000 description 1
- 238000007654 immersion Methods 0.000 description 1
- 230000001771 impaired effect Effects 0.000 description 1
- 239000011261 inert gas Substances 0.000 description 1
- 238000011835 investigation Methods 0.000 description 1
- 229910021506 iron(II) hydroxide Inorganic materials 0.000 description 1
- 239000010410 layer Substances 0.000 description 1
- 229910052749 magnesium Inorganic materials 0.000 description 1
- 239000000696 magnetic material Substances 0.000 description 1
- 229910052750 molybdenum Inorganic materials 0.000 description 1
- 238000000465 moulding Methods 0.000 description 1
- 229910052758 niobium Inorganic materials 0.000 description 1
- 239000007800 oxidant agent Substances 0.000 description 1
- 238000005498 polishing Methods 0.000 description 1
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- 229950011008 tetrachloroethylene Drugs 0.000 description 1
- 239000010409 thin film Substances 0.000 description 1
- 229910052720 vanadium Inorganic materials 0.000 description 1
- 239000002351 wastewater Substances 0.000 description 1
- 229910052726 zirconium Inorganic materials 0.000 description 1
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- Compounds Of Iron (AREA)
- Hard Magnetic Materials (AREA)
- Soft Magnetic Materials (AREA)
Abstract
Description
本発明は電波吸収体や土壌改良剤用多孔質鉄粉の原料となるマグネタイト粉末及びその製造方法に関するものである。 The present invention relates to a magnetite powder that is a raw material for a radio wave absorber and a porous iron powder for a soil conditioner, and a method for producing the same.
近年、鉄粉が土壌改良剤や電波吸収体に広く使用されるようになり、多孔質鉄粉開発の要望が増えてきている。 In recent years, iron powder has been widely used in soil conditioners and radio wave absorbers, and the demand for porous iron powder development has increased.
土壌改良剤として鉄粉が用いられるのは次の理由による。鉄粉を湿潤状態の土壌中におくと、Ｆｅイオンが溶け出し、このＦｅイオンが、土壌中のテトラクロロエチレンなどの有機ハロゲン化合物と反応して、エチレンなどの有機物とハロゲンに分解し、無害化する。 The reason why iron powder is used as a soil conditioner is as follows. When iron powder is placed in wet soil, Fe ions are dissolved, and this Fe ions react with organic halogen compounds such as tetrachloroethylene in the soil and decompose into organic substances such as ethylene and halogens to make them harmless. .
特許文献１にはＰ、Ｓ、Ｂの１種以上を含有し、比表面積が０．０１〜１．０ｍ２／ｇ、粒子径が１〜１０００μｍの鉄粉が開示されている。
また、鉄粉の表面積を増やすことによりＦｅイオンの溶出の増大を図る試みがなされているが、表面積の増大とともに発火しやすくなるという問題が生じている。Patent Document 1 discloses iron powder containing one or more of P, S, and B, having a specific surface area of 0.01 to 1.0 m 2 / g and a particle diameter of 1 to 1000 μm.
In addition, attempts have been made to increase the elution of Fe ions by increasing the surface area of the iron powder. However, there is a problem that ignition tends to occur as the surface area increases.
電波吸収体としての鉄粉は、現在、数１０ＭＨｚ〜１ＧＨｚ帯域の電波吸収に有用であることが知られている。鉄粉をより高い周波数の領域の電波を吸収するように、アスペクト比の工夫、特殊元素の添加など様々な試みがなされている。 It is known that iron powder as a radio wave absorber is currently useful for radio wave absorption in the tens of MHz to 1 GHz band. Various attempts have been made to devise aspect ratios and addition of special elements so that iron powder absorbs radio waves in a higher frequency range.
このような土壌改良剤や電波吸収体には主としてアトマイズ鉄粉がそのままあるいは還元処理されて用いられている。アトマイズ鉄粉を用いる限り、比表面積の大きい多孔質鉄粉を得ることは難しい。そこで、多孔質鉄粉を得るための方法を種々検討した結果、マグネタイト粉末から製造する方法を見出した。 Atomized iron powder is mainly used as such or after being subjected to a reduction treatment in such a soil conditioner and a radio wave absorber. As long as atomized iron powder is used, it is difficult to obtain porous iron powder having a large specific surface area. Therefore, as a result of various investigations on methods for obtaining porous iron powder, a method for producing from magnetite powder was found.
従来のマグネタイト粉末の製造方法として、例えば、水酸化第二鉄又はゲータイトを含むアルカリ性懸濁液をオートクレープを用いて水熱処理することにより水溶液からヘマタイト粒子を生成させ、このヘマタイト粒子を還元性ガス中で加熱還元する方法及び水酸化第一鉄を含むアルカリ性懸濁液を強酸化剤で急激に酸化することにより、又は特定の添加剤の存在下で第二鉄塩とアルカリとを水性媒体中で反応させて水酸化第二鉄を生成させ、該水酸化第二鉄を水熱処理することにより水溶液中からゲータイト粒子を生成させ、該ゲータイト粒子を加熱脱水後、還元性ガス中で加熱還元する方法が知られている。この方法は水溶液から生成した粒子を還元性ガス中で加熱還元することが必要であり、生成した粒子は平均粒径が１μｍ以下になる。 As a conventional method for producing magnetite powder, for example, an alkaline suspension containing ferric hydroxide or goethite is hydrothermally treated using an autoclave to generate hematite particles from an aqueous solution, and the hematite particles are reduced to a reducing gas. In an aqueous medium by fermenting a ferric salt and an alkali in an aqueous medium by rapidly oxidizing an alkaline suspension containing ferrous hydroxide with a strong oxidizing agent or in the presence of a specific additive To produce ferric hydroxide, hydrothermally treating the ferric hydroxide to produce goethite particles from an aqueous solution, heating and dehydrating the goethite particles, and reducing the heat in a reducing gas The method is known. In this method, it is necessary to thermally reduce particles generated from an aqueous solution in a reducing gas, and the generated particles have an average particle size of 1 μm or less.
特開昭６３−２０１０１９号公報には第一鉄塩溶液と炭酸アルカリ溶液を反応させて得られたＦｅＣＯ３を含む水溶液に酸素含有ガスを通気して平均粒径０．０３〜０．５μｍ、比表面積が７〜３０ｍ２／ｇのマグネタイト粉末の製造方法が開示されている。Japanese Patent Laid-Open No. 63-201019 discloses that an average particle size of 0.03 to 0.5 μm is obtained by passing an oxygen-containing gas through an aqueous solution containing FeCO 3 obtained by reacting a ferrous salt solution and an alkali carbonate solution. A method for producing a magnetite powder having a specific surface area of 7 to 30 m 2 / g is disclosed.
以上のような第一鉄塩水溶液あるいは第二鉄塩水溶液とアルカリ水溶液との反応に酸素含有ガスを通気することによりマグネタイトを製造する方法は、平均粒子径が１μｍ以下のマグネタイトを製造するには好適な方法であるが、平均粒子径が２μｍ以上のマグネタイトを製造するには適していない。 The method for producing magnetite by aerating an oxygen-containing gas to the reaction between the ferrous salt aqueous solution or ferric salt aqueous solution and the alkaline aqueous solution as described above is for producing magnetite having an average particle diameter of 1 μm or less. Although it is a suitable method, it is not suitable for producing magnetite having an average particle diameter of 2 μm or more.
平均粒子径が１μｍ以下のマグネタイトを還元した鉄粉は、活性度が高すぎて発火してしまうという問題があった。 The iron powder obtained by reducing magnetite having an average particle size of 1 μm or less has a problem that the activity is so high that it ignites.
本発明では多孔質鉄粉を得るために、還元処理前のマグネタイト粉末の表面積が大きいことが有効であり、また、還元処理後の発火防止には特殊元素の含有が有効であることを新たに見出した。 In the present invention, in order to obtain porous iron powder, it is effective that the surface area of the magnetite powder before the reduction treatment is large, and that the inclusion of a special element is effective for preventing ignition after the reduction treatment. I found it.
本発明のマグネタイト粉末は比表面積が４ｍ２／ｇ以上であって、平均粒子径が２〜９０μｍであるという特徴をもつ。比表面積が４ｍ２／ｇより小さいと、マグネタイト粉末を還元処理した鉄粉は、電波吸収体として使用した場合、渦電流が大きくなるため好ましくない。比表面積は６ｍ２／ｇ以上が好ましく、より好ましくは８ｍ２／ｇ以上である。本発明において、比表面積は窒素ガスを用いたＢＥＴ法で測定した値を用い、平均粒子径はレーザー回折法で測定したＤ５０の値を用いた。マグネタイト粉末の平均粒子径が２μｍより小さいとマグネタイト粉末を還元処理した鉄粉は発火しやすくなる。一方、マグネタイト粉末の平均粒子径が９０μｍより大きいとマグネタイト粉末を還元処理した鉄粉は樹脂と混練して電波吸収体にした場合、鉄粉の充填率が低下し、電波吸収性能が低下する。好ましくは平均粒子径は５〜１５μｍである。The magnetite powder of the present invention is characterized by a specific surface area of 4 m 2 / g or more and an average particle size of 2 to 90 μm. When the specific surface area is less than 4 m 2 / g, iron powder obtained by reducing magnetite powder is not preferable because eddy current increases when used as a radio wave absorber. The specific surface area is preferably 6 m 2 / g or more, more preferably 8 m 2 / g or more. In the present invention, the specific surface area is a value measured by a BET method using nitrogen gas, and the average particle diameter is a value of D50 measured by a laser diffraction method. When the average particle diameter of the magnetite powder is smaller than 2 μm, the iron powder obtained by reducing the magnetite powder is likely to ignite. On the other hand, when the average particle diameter of the magnetite powder is larger than 90 μm, when the iron powder obtained by reducing the magnetite powder is kneaded with a resin to form a radio wave absorber, the filling rate of the iron powder is lowered and the radio wave absorption performance is lowered. Preferably the average particle size is 5-15 μm.
上述の通り本発明のマグネタイト粉末の特徴は、比表面積、平均粒子径に代表される形状の特異性である。よって、マグネタイト粉末の各々の用途における種々の特性を向上する目的でＦｅ以外の成分を含有することができる。また、マグネタイト粉末の各々の用途における使用を妨げない範囲で鉄以外の成分を含有することができる。例えば原料として後述する希土類−鉄−ホウ素系、希土類−鉄−窒素系の永久磁石用合を原料として用いた場合、原料に由来するＦｅ以外の成分（例えばＹを含む希土類元素、Ｂ、Ｃ、Ｃｏ、Ａｌ、Ｃｕ、Ｇａ、Ｔｉ、Ｚｒ、Ｎｂ、Ｖ、Ｃｒ、Ｍｏ、Ｍｎ、Ｎｉ、Ｓｉ、Ｍｇ、Ｃａ等）を含有することができる。鉄以外の成分の含有量は１５原子％以下が好ましい。 As described above, the feature of the magnetite powder of the present invention is the specificity of the shape represented by the specific surface area and the average particle diameter. Therefore, components other than Fe can be contained for the purpose of improving various properties in each application of the magnetite powder. Moreover, components other than iron can be contained in the range which does not prevent the use in each use of magnetite powder. For example, when a rare earth-iron-boron based or rare earth-iron-nitrogen based permanent magnet combination described later is used as a raw material, components other than Fe derived from the raw material (for example, rare earth elements including Y, B, C, (Co, Al, Cu, Ga, Ti, Zr, Nb, V, Cr, Mo, Mn, Ni, Si, Mg, Ca, etc.). The content of components other than iron is preferably 15 atomic% or less.
本発明のマグネタイト粉末は酸素を除く金属元素の合計を１００原子％とした場合、Ｙを含む希土類元素、Ａｌ、Ｔｉ、Ｓｉ、Ｍｎ、Ｃｏ、Ｎｉの中から選ばれた１種以上の元素を０．０１〜１５原子％含有することが好ましい。Ｙを含む希土類元素、Ａｌ、Ｔｉ、Ｓｉ、Ｍｎの酸素との親和力はＦｅよりも大きく、鉄粒子の表面に酸化物層を形成しやすい。このような元素を含むマグネタイト粉末を還元処理した鉄粉は表面層に酸化物が存在することにより発火を回避でき、その上、鉄粉の粒子同士の接触による導通に起因する渦電流発生を防止できる。特に希土類元素を１〜５原子％含有することが好ましい。希土類元素としては、Ｎｄ、Ｐｒ、Ｔｂ、Ｄｙを含有することが好ましい。純鉄は透磁率が大きく、電波吸収用磁性体として優れているが、Ｃｏ、Ａｌ、Ｓｉ、Ｎｉなどの元素を含有すると透磁率をさらに大きくすることが可能な点で好ましい。これらの元素の添加量は、０．０１原子％以下では効果が十分でなく、１５原子％より多いとマグネタイト粉末を還元処理した鉄粉は電波吸収特性が低下し、また、これら元素はマグネタイトの主成分であるＦｅに比べて高価であるため、経済性を損なう。 The magnetite powder of the present invention contains at least one element selected from rare earth elements including Y, Al, Ti, Si, Mn, Co, and Ni when the total amount of metal elements excluding oxygen is 100 atomic%. It is preferable to contain 0.01-15 atomic%. The affinity of rare earth elements including Y, Al, Ti, Si, and Mn with oxygen is larger than that of Fe, and an oxide layer is easily formed on the surface of iron particles. Iron powder obtained by reducing magnetite powder containing such elements can avoid ignition due to the presence of oxide in the surface layer, and also prevents eddy currents from being generated due to contact between the iron powder particles. it can. In particular, it is preferable to contain 1 to 5 atomic% of rare earth elements. As the rare earth element, it is preferable to contain Nd, Pr, Tb, and Dy. Pure iron has a high magnetic permeability and is excellent as a radio wave absorbing magnetic material. However, it is preferable to contain elements such as Co, Al, Si, and Ni because the magnetic permeability can be further increased. When the addition amount of these elements is 0.01 atomic% or less, the effect is not sufficient. When the addition amount exceeds 15 atomic%, the iron powder obtained by reducing the magnetite powder has reduced radio wave absorption characteristics, and these elements are not magnetite. Since it is more expensive than Fe, which is the main component, the economy is impaired.
本発明のマグネタイト粉末は比表面積が大きいため、これを還元処理した鉄粉は比表面積が大きく、湿潤状態において有機ハロゲン化合物を分解する性能が優れ、汚染土壌、排水の浄化剤として好適なものとなる。 Since the magnetite powder of the present invention has a large specific surface area, the iron powder obtained by reducing this has a large specific surface area and has an excellent performance of decomposing organic halogen compounds in a wet state, and is suitable as a purification agent for contaminated soil and waste water. Become.
上述したマグネタイト粉末は、金属、原料合金を原料として本発明の方法より製造できる。本発明のマグネタイト粉末の製造方法は、下記の工程１、工程２Ａ、工程３Ａを含むか、あるいは工程１、工程２Ｂ、工程３Ｂを含む。
（工程１）Ｍ元素を含有する鉄を主成分とする合金（Ｆｅ−Ｍ合金）を準備する工程
（工程２Ａ）該Ｆｅ−Ｍ合金を酸溶液に浸漬し、Ｍ元素を溶出させ、鉄の水酸化物を主成分とする固形物（Ｆｅ固形物）を得る工程
（工程３Ａ）該Ｆｅ固形物をアルカリ溶液に浸漬し、マグネタイト粉末を得る工程
あるいは、
（工程１）Ｍ元素を含有する鉄を主成分とする合金（Ｆｅ−Ｍ合金）を準備する工程
（工程２Ｂ）該Ｆｅ−Ｍ合金をアルカリ溶液に浸漬し、マグネタイトを主成分とする固形物（中間マグネタイト固形物）を得る工程
（工程３Ｂ）該中間マグネタイト固形物を酸溶液に浸漬し、Ｍ元素を溶出させ、マグネタイト粉末を得る工程The magnetite powder described above can be produced by the method of the present invention using a metal or a raw material alloy as a raw material. The method for producing a magnetite powder of the present invention includes the following step 1, step 2A, and step 3A, or includes step 1, step 2B, and step 3B.
(Step 1) Step of preparing an iron-based alloy containing M element (Fe-M alloy) (Step 2A) The Fe-M alloy is immersed in an acid solution to elute M element, Step of obtaining a solid (Fe solid) containing hydroxide as a main component (Step 3A) Step of immersing the Fe solid in an alkali solution to obtain a magnetite powder, or
(Step 1) Step of preparing an iron-based alloy containing Fe element (Fe-M alloy) (Step 2B) A solid material containing magnetite as a main component by immersing the Fe-M alloy in an alkaline solution Step of obtaining (intermediate magnetite solid) (step 3B) Step of immersing the intermediate magnetite solid in an acid solution to elute M element to obtain magnetite powder
工程１において、Ｍ元素を含有する鉄を主成分とする合金（Ｆｅ−Ｍ合金）を準備する。Ｍ元素としては、Ｙを含む希土類元素、アルカリ土類金属、Ｐ、Ｃ、Ｓ、Ａｌ、Ｔｉ、Ｓｉ、Ｍｎ、Ｃｏ、Ｂ、Ｃｕ、Ｇａ等を用いることができる。Ｍ元素は工程２Ａ、工程３Ｂにおいて酸溶液に溶出されるが、工程２Ａ、工程３Ｂにおける種々の条件により、溶出したり、溶出しなかったりするため、上述の元素が常にＭ元素であるというわけではない。 In step 1, an alloy containing iron containing M element as a main component (Fe-M alloy) is prepared. As the M element, rare earth elements including Y, alkaline earth metals, P, C, S, Al, Ti, Si, Mn, Co, B, Cu, Ga, and the like can be used. The element M is eluted in the acid solution in the steps 2A and 3B, but may or may not be eluted depending on various conditions in the steps 2A and 3B. Therefore, the above element is always the M element. is not.
マグネタイト粉末を還元処理した鉄粉の種々の特性を向上させる目的、または特性を阻害しない範囲で、Ｍ元素及びＦｅ以外の元素を含有させてもよい。所定の組成となるように原料として準備したＭ元素、Ｆｅ、その他の元素の単金属、原料合金を溶解した後、凝固させることによりＭ元素を含有する鉄を主成分とする合金（Ｆｅ−Ｍ合金）を得ることができる。 You may contain elements other than M element and Fe in the objective which improves the various characteristics of the iron powder which reduced-processed the magnetite powder, or the range which does not inhibit a characteristic. An alloy (Fe-M) containing iron containing M element as a main component by melting M element, Fe, single metal of other elements and raw material alloy prepared as raw materials so as to have a predetermined composition and then solidifying Alloy) can be obtained.
原料の単金属、原料合金は高周波溶解法、アーク溶解法などいずれの方法で溶解してもよく、凝固方法はモールド法、アトマイズ法、ストリップキャスト法いずれの方法を採用してもよい。また、次工程以降で行うアルカリ溶液及び酸溶液への浸漬処理の作業効率を上げること、およびマグネタイト粉末の粒子径を調整することを目的に、あらかじめ、数ｍｍ以下に粉砕しておくことが有効である。工程２Ａ、工程３Ａ、工程２Ｂ及び工程３Ｂの反応を促進するためには粉砕粉の大きさは小さいほうがよい。好ましくは０．１ｍｍ以下がよい。 The raw material single metal and the raw material alloy may be melted by any method such as a high frequency melting method or an arc melting method, and the solidification method may be any of a molding method, an atomizing method, and a strip casting method. It is also effective to pulverize to a few millimeters or less in advance for the purpose of increasing the working efficiency of the immersion treatment in the alkaline solution and acid solution performed in the subsequent steps and adjusting the particle size of the magnetite powder. It is. In order to promote the reaction of Step 2A, Step 3A, Step 2B and Step 3B, the size of the pulverized powder is preferably small. Preferably it is 0.1 mm or less.
また、粉砕工程の前に、マグネタイト及びマグネタイトから製造する鉄粉の特性を考慮して熱処理工程を入れてもよい。好ましい熱処理条件は加熱温度５００℃〜１２００℃、加熱時間１分〜２４時間であるが、必要に応じてこの範囲以外の熱処理を行うことができる。 Moreover, you may put the heat processing process in consideration of the characteristic of the iron powder manufactured from a magnetite and magnetite before a grinding | pulverization process. Preferable heat treatment conditions are a heating temperature of 500 ° C. to 1200 ° C. and a heating time of 1 minute to 24 hours, but heat treatment outside this range can be performed as necessary.
Ｆｅ−Ｍ合金としては、工業的に広く用いられている希土類−鉄−ホウ素系、希土類−鉄−窒素系の永久磁石用合金、希土類−鉄−ケイ素系の磁気冷凍材料用合金等を用いることができる。これらを使用した場合、主に希土類元素がＭ元素に相当する。これらは本発明のマグネタイト粉末用に製造されたものに限らず、磁石、磁気冷凍材料に加工する際、不要部の切除、研削、研磨で発生した合金屑等を用いることができる。 As an Fe-M alloy, a rare earth-iron-boron-based alloy, a rare-earth-iron-nitrogen-based alloy for permanent magnets, a rare-earth-iron-silicon-based alloy for magnetic refrigerating materials, or the like is used. Can do. When these are used, the rare earth element mainly corresponds to the M element. These are not limited to those produced for the magnetite powder of the present invention, and can be used for scraps of metal, alloy scraps, etc. generated by excision, grinding and polishing of unnecessary parts when processing into magnets and magnetic refrigeration materials.
工程２Ａにおいて、工程１で製造したＦｅ−Ｍ合金を酸溶液に浸漬し、固形物中のＭ元素を選択的に溶出し、鉄の水酸化物を主成分とする固形物（Ｆｅ固形物）にする。鉄の水酸化物を主成分とするとは、Ｘ線回折スペクトルを測定した際、鉄の水酸化物に由来する回折ピークが主要なピークとして観察されることを意味する。Ｆｅ固形物を得るための条件は、Ｆｅ−Ｍ合金の組成、Ｆｅ−Ｍ合金の形状等により異なるが、適宜、使用する酸溶液の種類、酸の濃度、酸溶液の使用量、反応温度、反応時間等を制御して容易に行うことができる。経済性を損なわない条件で行うことが好ましい。使用する酸溶液としては、塩酸、硝酸、硫酸、フッ酸あるいはそれらの混酸を用いることができる。使用する酸溶液の濃度は、例えば０．１〜１０ｍｏｌ／ｌ、好ましくは１〜５ｍｏｌ／ｌである。使用する酸溶液の使用量は、例えばＦｅ−Ｍ合金中のＭ元素のモル数の０．１〜１０倍量である。反応温度は、例えば３０℃以上、好ましくは４０℃以上、より好ましくは６０℃以上である。反応時間は１〜１００時間、好ましくは１０〜２４時間である。酸素を含有するガスを酸溶液中に吹き込むと効果的に反応が促進される。Ｍ元素を選択的に溶出することにより、比表面積の大きいＦｅ固形物を得ることができる。Ｍ元素の１部は残存させてもよい。また、Ｆｅ元素の１部を溶出させてもよく、ｐＨを調整し、溶出したＦｅ元素を水酸化物として析出させてもよい。反応終了後、Ｆｅ固形物は反応溶液から濾別され、必要に応じて洗浄を行うことができる。 In Step 2A, the Fe-M alloy produced in Step 1 is immersed in an acid solution to selectively elute M element in the solid, and a solid containing iron hydroxide as the main component (Fe solid). To. Having iron hydroxide as the main component means that a diffraction peak derived from iron hydroxide is observed as a main peak when an X-ray diffraction spectrum is measured. The conditions for obtaining the Fe solid matter vary depending on the composition of the Fe-M alloy, the shape of the Fe-M alloy, etc., but the type of acid solution used, the concentration of the acid, the amount of acid solution used, the reaction temperature, It can be carried out easily by controlling the reaction time and the like. It is preferable to carry out it on the conditions which do not impair economical efficiency. As the acid solution to be used, hydrochloric acid, nitric acid, sulfuric acid, hydrofluoric acid or a mixed acid thereof can be used. The concentration of the acid solution used is, for example, 0.1 to 10 mol / l, preferably 1 to 5 mol / l. The amount of the acid solution used is, for example, 0.1 to 10 times the number of moles of the M element in the Fe-M alloy. The reaction temperature is, for example, 30 ° C. or higher, preferably 40 ° C. or higher, more preferably 60 ° C. or higher. The reaction time is 1 to 100 hours, preferably 10 to 24 hours. When a gas containing oxygen is blown into the acid solution, the reaction is effectively promoted. By selectively eluting the element M, an Fe solid having a large specific surface area can be obtained. One part of the M element may remain. Moreover, 1 part of Fe element may be eluted, pH may be adjusted, and the eluted Fe element may be precipitated as a hydroxide. After completion of the reaction, the Fe solid matter is filtered off from the reaction solution and can be washed as necessary.
工程３Ａにおいて、工程２Ａで製造したＦｅ固形物をアルカリ溶液に浸漬し、Ｆｅを主成分とするマグネタイト粉末にする。マグネタイト粉末を得るための条件は、Ｆｅ固形物の組成、Ｆｅ固形物の形状等により異なるが、適宜、使用するアルカリ溶液の種類、アルカリ溶液の濃度、アルカリ溶液の使用量、反応温度、反応時間等を制御して容易に行うことができる。経済性を損なわない条件で行うことが好ましい。使用するアルカリ溶液としては、例えばアルカリ金属塩の水溶液、アンモニア水溶液またはアンモニウム塩水溶液等が挙げられる。前記アルカリ金属塩としては、例えばナトリウム、カリウム、リチウム等のアルカリ金属の水酸化物、炭酸塩等が挙げられ、特に反応性の点から水酸化リチウム、水酸化カリウム、水酸化ナトリウム等の水酸化物が望ましい。前記アンモニウム塩としては、例えば炭酸アンモニウム、炭酸ナトリウム、炭酸水素ナトリウム等が挙げられる。使用するアルカリ溶液の濃度は、例えば０．１〜１０ｍｏｌ／ｌ、好ましくは１〜５ｍｏｌ／ｌである。使用するアルカリ溶液の使用量は、例えばＦｅ−Ｍ合金におけるＦｅ元素のモル数の０．１〜１０倍量である。反応温度は、例えば３０℃以上、好ましくは４０℃以上、より好ましくは６０℃以上である。反応時間は１〜１００時間、好ましくは１０〜２４時間である。大気圧以上に加圧できる反応容器を用いることで効果的に反応が促進される。また、酸素を含有するガスをアルカリ溶液中に吹き込むと効果的に反応が促進される。反応終了後、マグネタイト粉末は反応溶液から濾別され、必要に応じて洗浄を行うことができる。マグネタイト粉末は主にＦｅ酸化物、及び１部残存したＭ元素やその他の元素の酸化物、水酸化物、及び１部残存したＭ元素やその他の元素と用いた酸の陰イオンとの化合物、並びに水和水、付着水等の水分を含有する。 In Step 3A, the Fe solid material produced in Step 2A is immersed in an alkaline solution to obtain a magnetite powder containing Fe as a main component. The conditions for obtaining the magnetite powder vary depending on the composition of the Fe solid, the shape of the Fe solid, etc., but the type of the alkali solution used, the concentration of the alkali solution, the amount of the alkali solution used, the reaction temperature, the reaction time, as appropriate. Etc. can be easily performed by controlling the above. It is preferable to carry out it on the conditions which do not impair economical efficiency. Examples of the alkaline solution to be used include an aqueous solution of an alkali metal salt, an aqueous ammonia solution or an aqueous ammonium salt solution. Examples of the alkali metal salt include hydroxides and carbonates of alkali metals such as sodium, potassium and lithium, and hydroxides such as lithium hydroxide, potassium hydroxide and sodium hydroxide are particularly reactive. Things are desirable. As said ammonium salt, ammonium carbonate, sodium carbonate, sodium hydrogencarbonate etc. are mentioned, for example. The concentration of the alkaline solution to be used is, for example, 0.1 to 10 mol / l, preferably 1 to 5 mol / l. The amount of the alkaline solution used is, for example, 0.1 to 10 times the number of moles of Fe element in the Fe-M alloy. The reaction temperature is, for example, 30 ° C. or higher, preferably 40 ° C. or higher, more preferably 60 ° C. or higher. The reaction time is 1 to 100 hours, preferably 10 to 24 hours. The reaction is effectively promoted by using a reaction vessel that can be pressurized to atmospheric pressure or higher. Further, when a gas containing oxygen is blown into the alkaline solution, the reaction is effectively promoted. After completion of the reaction, the magnetite powder is filtered off from the reaction solution and can be washed if necessary. Magnetite powder is mainly composed of Fe oxide, 1 part remaining M element and other element oxide, hydroxide, 1 part remaining M element and other element and anion of acid used, In addition, it contains water such as hydration water and adhering water.
工程２Ｂにおいて、工程１で製造したＦｅ−Ｍ合金をアルカリ溶液に浸漬し、マグネタイトを主成分とする固形物（中間マグネタイト固形物）にする。マグネタイトを主成分とするとは、Ｘ線回折スペクトルを測定した際、マグネタイトに由来する回折ピークが主要なピークとして観察されることを意味する。中間マグネタイト固形物を得るための条件は、Ｆｅ−Ｍ合金の組成、Ｆｅ−Ｍ合金の形状等により異なるが、適宜、使用するアルカリ溶液の種類、アルカリ溶液の濃度、アルカリ溶液の使用量、反応温度、反応時間等を制御して容易に行うことができる。経済性を損なわない条件で行うことが好ましい。使用するアルカリ溶液としては、例えばアルカリ金属塩の水溶液、アンモニア水溶液またはアンモニウム塩水溶液等が挙げられる。前記アルカリ金属塩としては、例えばナトリウム、カリウム、リチウム等のアルカリ金属の水酸化物、炭酸塩等が挙げられ、特に反応性の点から水酸化リチウム、水酸化カリウム、水酸化ナトリウム等の水酸化物が望ましい。前記アンモニウム塩としては、例えば炭酸アンモニウム、炭酸ナトリウム、炭酸水素ナトリウム等が挙げられる。使用するアルカリ溶液の濃度は、例えば０．１〜１０ｍｏｌ／ｌ、好ましくは１〜５ｍｏｌ／ｌである。使用するアルカリ溶液の使用量は、例えばＦｅ−Ｍ合金中のＦｅ元素のモル数の０．１〜１０倍量である。反応温度は、例えば３０℃以上、好ましくは４０℃以上、より好ましくは６０℃以上である。反応時間は１〜１００時間、好ましくは１０〜２４時間である。大気圧以上に加圧できる反応容器を用いることで効果的に反応が促進される。また、酸素を含有するガスをアルカリ溶液中に吹き込むと効果的に反応が促進される。反応終了後、中間マグネタイト固形物は反応溶液から濾別され、必要に応じて洗浄を行うことができる。工程２Ｂの条件によりＭ元素の１部およびＦｅ以外の含有元素が溶出する場合がある。 In step 2B, the Fe-M alloy produced in step 1 is immersed in an alkaline solution to form a solid (intermediate magnetite solid) containing magnetite as a main component. “Magnetite as a main component” means that a diffraction peak derived from magnetite is observed as a main peak when an X-ray diffraction spectrum is measured. The conditions for obtaining the intermediate magnetite solid vary depending on the composition of the Fe-M alloy, the shape of the Fe-M alloy, etc., but the type of the alkali solution used, the concentration of the alkali solution, the amount of the alkali solution used, the reaction It can be carried out easily by controlling the temperature, reaction time and the like. It is preferable to carry out it on the conditions which do not impair economical efficiency. Examples of the alkaline solution to be used include an aqueous solution of an alkali metal salt, an aqueous ammonia solution or an aqueous ammonium salt solution. Examples of the alkali metal salt include hydroxides and carbonates of alkali metals such as sodium, potassium and lithium, and hydroxides such as lithium hydroxide, potassium hydroxide and sodium hydroxide are particularly reactive. Things are desirable. As said ammonium salt, ammonium carbonate, sodium carbonate, sodium hydrogencarbonate etc. are mentioned, for example. The concentration of the alkaline solution to be used is, for example, 0.1 to 10 mol / l, preferably 1 to 5 mol / l. The amount of the alkaline solution used is, for example, 0.1 to 10 times the number of moles of Fe element in the Fe-M alloy. The reaction temperature is, for example, 30 ° C. or higher, preferably 40 ° C. or higher, more preferably 60 ° C. or higher. The reaction time is 1 to 100 hours, preferably 10 to 24 hours. The reaction is effectively promoted by using a reaction vessel that can be pressurized to atmospheric pressure or higher. Further, when a gas containing oxygen is blown into the alkaline solution, the reaction is effectively promoted. After completion of the reaction, the intermediate magnetite solid is filtered off from the reaction solution and can be washed if necessary. Depending on the conditions of step 2B, 1 part of the M element and contained elements other than Fe may be eluted.
工程３Ｂにおいて、工程２Ｂで製造した中間マグネタイト固形物を酸溶液に浸漬し、該固形物中のＭ元素を選択的に溶出し、Ｆｅを主成分とするマグネタイト粉末にする。マグネタイト粉末を得るための条件は、中間マグネタイト固形物の組成、中間マグネタイト固形物の形状等により異なるが、適宜、使用する酸溶液の種類、酸の濃度、酸溶液の使用量、反応温度、反応時間等を制御して容易に行うことができる。経済性を損なわない条件で行うことが好ましい。使用する酸溶液としては、塩酸、硝酸、硫酸、フッ酸あるいはそれらの混酸を用いることができる。使用する酸溶液の濃度は、例えば０．１〜１０ｍｏｌ／ｌ、好ましくは１〜５ｍｏｌ／ｌである。使用する酸溶液の使用量は、例えばＦｅ−Ｍ合金におけるＭ元素のモル数の０．１〜１０倍量である。反応温度は、例えば３０℃以上、好ましくは４０℃以上、より好ましくは６０℃以上である。反応時間は１〜１００時間、好ましくは１０〜２４時間である。酸素を含有するガスを酸溶液中に吹き込むと効果的に反応が促進される。Ｍ元素を選択的に溶出するには、Ｍ元素たけが溶出するｐＨ域に制御して行うことができる。Ｍ元素を選択的に溶出することにより、比表面積の大きいＦｅを主成分とするマグネタイト粉末を得ることができる。適宜、条件を制御することにより、Ｍ元素の１部を残存させ、あるいは、Ｆｅ元素の１部を溶出させてもよい。反応終了後、マグネタイト粉末は反応溶液から濾別され、必要に応じて洗浄を行うことができる。マグネタイト粉末は主にＦｅ酸化物、及び１部残存したＭ元素やその他の元素の酸化物、水酸化物、及び１部残存したＭ元素やその他の元素と用いた酸の陰イオンとの化合物、並びに水和水、付着水等の水分を含有する。 In step 3B, the intermediate magnetite solid produced in step 2B is immersed in an acid solution, and element M in the solid is selectively eluted to form a magnetite powder containing Fe as a main component. The conditions for obtaining magnetite powder vary depending on the composition of the intermediate magnetite solid, the shape of the intermediate magnetite solid, etc., but the type of acid solution used, the concentration of acid, the amount of acid solution used, the reaction temperature, the reaction It can be easily performed by controlling time and the like. It is preferable to carry out it on the conditions which do not impair economical efficiency. As the acid solution to be used, hydrochloric acid, nitric acid, sulfuric acid, hydrofluoric acid or a mixed acid thereof can be used. The concentration of the acid solution used is, for example, 0.1 to 10 mol / l, preferably 1 to 5 mol / l. The amount of the acid solution used is, for example, 0.1 to 10 times the number of moles of M element in the Fe-M alloy. The reaction temperature is, for example, 30 ° C. or higher, preferably 40 ° C. or higher, more preferably 60 ° C. or higher. The reaction time is 1 to 100 hours, preferably 10 to 24 hours. When a gas containing oxygen is blown into the acid solution, the reaction is effectively promoted. In order to selectively elute the M element, the pH can be controlled within the pH range where only the M element is eluted. By selectively eluting the element M, a magnetite powder mainly composed of Fe having a large specific surface area can be obtained. By appropriately controlling the conditions, 1 part of the M element may remain or 1 part of the Fe element may be eluted. After completion of the reaction, the magnetite powder is filtered off from the reaction solution and can be washed if necessary. Magnetite powder is mainly composed of Fe oxide, 1 part remaining M element and other element oxide, hydroxide, 1 part remaining M element and other element and anion of acid used, In addition, it contains water such as hydration water and adhering water.
例えばＦｅ−Ｍ合金として希土類−鉄−ホウ素系の永久磁石用合金を用いた場合、最終的に得られるマグネタイト粉末に希土類元素を含有させることができる。このようなマグネタイト粉末を原料として製造した鉄粉は表層部に希土類元素の酸化物が存在するため、空気に触れても発火しにくいという特性を付与することができる。 For example, when a rare earth-iron-boron permanent magnet alloy is used as the Fe-M alloy, the finally obtained magnetite powder can contain a rare earth element. The iron powder produced using such a magnetite powder as a raw material has a rare earth element oxide in the surface layer portion, so that it can be imparted with a characteristic that it does not easily ignite even when exposed to air.
上述の工程１、工程２Ａ、工程３Ａ、あるいは工程１、工程２Ｂ、工程３Ｂを行って得られたマグネタイト粉末は、必要に応じて、工程４を行うことができる。工程４では、マグネタイト粉末を４００℃以下の温度に加熱する。加熱雰囲気は酸素を含む雰囲気でも不活性ガス雰囲気でもよい。乾燥温度が４００℃を越えるとマグネタイトの一部がヘマタイトになる。ヘマタイトを含有してもよいがヘマタイトは鉄粉を得るために還元雰囲気で処理したときに水蒸気が多く発生し、その処理に余計なコストがかかる。そのため、ヘマタイトは少ない方がよい。したがって、加熱温度は４００℃未満がよい。このマグネタイト粉末を水素を含有するガスを用いて還元することにより多孔質鉄粉を得ることができる。 The magnetite powder obtained by performing the above-mentioned step 1, step 2A, step 3A, or step 1, step 2B, step 3B can perform step 4 as necessary. In step 4, the magnetite powder is heated to a temperature of 400 ° C. or lower. The heating atmosphere may be an atmosphere containing oxygen or an inert gas atmosphere. When the drying temperature exceeds 400 ° C., part of the magnetite becomes hematite. Although hematite may be contained, hematite generates a lot of water vapor when treated in a reducing atmosphere in order to obtain iron powder, and the treatment requires extra cost. Therefore, less hematite is better. Therefore, the heating temperature is preferably less than 400 ° C. Porous iron powder can be obtained by reducing the magnetite powder using a gas containing hydrogen.
工程２Ａ及び工程３Ｂで溶出させたＭ元素を公知の沈澱分別法や溶媒抽出法等で回収・再利用することにより、資源の有効利用が可能である。 By recovering and reusing the element M eluted in step 2A and step 3B by a known precipitation fractionation method or solvent extraction method, resources can be effectively used.
本発明の平均粒径が２〜９０μｍ、比表面積が４ｍ２／ｇ以上のマグネタイト粉末はＭ元素を含有するため、還元処理されても、発火性の低い多孔質鉄粉にすることができる。Since the magnetite powder of the present invention having an average particle size of 2 to 90 μm and a specific surface area of 4 m 2 / g or more contains M element, it can be made into a porous iron powder having low ignitability even if it is reduced.
次に実施例により本発明を詳述する。Next, the present invention will be described in detail by way of examples.
（実施例１）
組成が１２．９Ｎｄ−０．５Ｃｏ−６．０Ｂ−８０．６Ｆｅとなるように配合した原料をアルゴン雰囲気中で、高周波溶解炉で溶解し、ストリップキャスティング法により厚さ約０．６ｍｍの合金薄帯を得た。この合金薄帯を粉砕して平均粒子径が約１５μｍの合金粉末を得た。この粉末５００ｇを１０００ｍｌの純水に混ぜ合金スラリーとした。このスラリーを攪拌し、毎分３００ｍｌの空気を吹き込みながら５ｍｏｌ／ｌの硝酸水溶液を添加し、空気の吹き込み量と硝酸水溶液の投入速度を制御して６０℃を超えないように反応させ、ｐＨ５．５となった時点で硝酸水溶液の投入を終了し、以後２時間空気を吹き込みながら攪拌を行った。硝酸水溶液の総投入量は１６００ｍｌであった。得られた溶液をヌッチェ式濾過機で濾過して、沈殿物と溶液を分離した。沈殿物のＸ線回折スペクトルを測定した結果、水酸化第二鉄を主とするものであった。次に、この沈殿物を１０００ｍｌの純水に混ぜスラリー状にした。反応容器としてオートクレーブを用い、攪拌しながら５ｍｏｌ／ｌの水酸化ナトリウム水溶液１６００ｍｌを添加し、１５０℃で１０時間攪拌反応させた。スラリー中に残存する固形物をヌッチェ式ろ過機でろ過し、マグネタイト粉末を得た。得られたマグネタイト粉末をデカンテーション法により洗浄した。このマグネタイト粉末をＩＣＰ分析したところ、その組成は１．６２Ｎｄ−０．７０Ｃｏ−０．８４Ｂ−９６．８４Ｆｅであった。このマグネタイトを３００℃で大気中５時間加熱した。加熱後のマグネタイト粉末についてＢＥＴ法により比表面積、レーザー回折法により平均粒子径（Ｄ５０）を測定した。その結果、ＢＥＴ値は２０．５ｍ２／ｇ、平均粒子径は１７．５μｍであった。Example 1
The raw material blended so that the composition becomes 12.9Nd-0.5Co-6.0B-80.6Fe was melted in a high-frequency melting furnace in an argon atmosphere, and an alloy thin film having a thickness of about 0.6 mm was formed by strip casting. I got a belt. The alloy ribbon was pulverized to obtain an alloy powder having an average particle size of about 15 μm. 500 g of this powder was mixed with 1000 ml of pure water to obtain an alloy slurry. The slurry is stirred, 5 mol / l nitric acid aqueous solution is added while blowing 300 ml of air per minute, and the reaction is performed so as not to exceed 60 ° C. by controlling the amount of air blown and the nitric acid aqueous solution feeding speed. When 5 was reached, the addition of the nitric acid aqueous solution was terminated, and then stirring was performed while blowing air for 2 hours. The total amount of nitric acid aqueous solution was 1600 ml. The resulting solution was filtered with a Nutsche filter to separate the precipitate from the solution. As a result of measuring the X-ray diffraction spectrum of the precipitate, it was mainly composed of ferric hydroxide. Next, this precipitate was mixed with 1000 ml of pure water to form a slurry. Using an autoclave as a reaction vessel, 1600 ml of a 5 mol / l sodium hydroxide aqueous solution was added with stirring, and the reaction was stirred at 150 ° C. for 10 hours. The solid matter remaining in the slurry was filtered with a Nutsche filter to obtain a magnetite powder. The obtained magnetite powder was washed by a decantation method. When this magnetite powder was analyzed by ICP, the composition was 1.62Nd-0.70Co-0.84B-96.84Fe. The magnetite was heated at 300 ° C. in the atmosphere for 5 hours. The magnetite powder after heating was measured for specific surface area by BET method and average particle diameter (D50) by laser diffraction method. As a result, the BET value was 20.5 m 2 / g, and the average particle size was 17.5 μm.
（実施例２）
組成が１０．９Ｎｄ−３．１０Ｄｙ−０．５０Ｃｏ−６．１０Ｂ−７９．４Ｆｅとなるように配合した原料をアルゴン雰囲気中で、高周波溶解炉で溶解し、ストリップキャスティング法により厚さ約０．４ｍｍの合金薄帯を得た。この合金薄帯を粉砕して平均粒子径が約１０μｍの合金粉末を得た。この粉末５００ｇを１０００ｍｌの純水に混ぜ合金スラリーとした。このスラリーを攪拌し、毎分３００ｍｌの空気を吹き込みながら２ｍｏｌ／ｌの水酸化ナトリウム水溶液２５００ｍｌを添加し、６０℃に昇温したのち、２４時間攪拌反応させた。得られた溶液をヌッチェ式濾過機で濾過して、沈殿物と溶液を分離した。次に、この沈殿物を１０００ｍｌの純水に混ぜスラリー状にした。このスラリーに５ｍｏｌ／ｌの塩酸水溶液１５００ｍｌを添加した。スラリーの温度は６０℃を保った。十分に反応を進行させた後、スラリー中に残存する固形物をヌッチェ式ろ過機でろ過し、マグネタイト粉末を得た。得られたマグネタイト粉末をデカンテーション法により洗浄した。このマグネタイト粉末をＩＣＰ分析したところ、その組成は１．４１Ｎｄ−０．４５Ｄｙ−０．７２Ｃｏ−０．７０Ｂ−９６．７Ｆｅであった。次いで、このマグネタイト粉末を７等分し、それぞれ１００、２００、３００、４００、５００、６００、７００℃で大気中５時間加熱した。加熱後のマグネタイト粉末についてＢＥＴ法により比表面積、レーザー回折法により平均粒子径（Ｄ５０）を測定した。また図１、図２にそれぞれ３００℃、４００℃で加熱して得られたマグネタイト粉末のＸ線回折スペクトルを示す。４００℃未満の加熱では酸化物はマグネタイトのみであるが、４００℃以上の加熱ではヘマタイトが析出している。また、図３に示す比表面積と加熱温度の関係から、３００℃以上の加熱で比表面積が著しく小さくなり、６００℃では４ｍ２／ｇ以下となる。したがって、比表面積が４ｍ２／ｇ以上の値を得るには６００℃以下の加熱が必要であることがわかる。図３に示す平均粒子径と加熱温度の関係から、平均粒子径は加熱温度が上がるにつれ若干小さくなる傾向がある。(Example 2)
The raw materials blended so as to have a composition of 10.9Nd-3.10Dy-0.50Co-6.10B-79.4Fe were melted in a high-frequency melting furnace in an argon atmosphere, and a thickness of about 0. A 4 mm alloy ribbon was obtained. The alloy ribbon was pulverized to obtain an alloy powder having an average particle size of about 10 μm. 500 g of this powder was mixed with 1000 ml of pure water to obtain an alloy slurry. The slurry was stirred, 2500 ml of a 2 mol / l aqueous sodium hydroxide solution was added while blowing 300 ml of air per minute, the temperature was raised to 60 ° C., and the reaction was stirred for 24 hours. The resulting solution was filtered with a Nutsche filter to separate the precipitate from the solution. Next, this precipitate was mixed with 1000 ml of pure water to form a slurry. To this slurry, 1500 ml of 5 mol / l hydrochloric acid aqueous solution was added. The temperature of the slurry was kept at 60 ° C. After allowing the reaction to proceed sufficiently, the solid matter remaining in the slurry was filtered with a Nutsche filter to obtain a magnetite powder. The obtained magnetite powder was washed by a decantation method. When this magnetite powder was analyzed by ICP, the composition was 1.41Nd-0.45Dy-0.72Co-0.70B-96.7Fe. Next, this magnetite powder was divided into seven equal parts and heated in air at 100, 200, 300, 400, 500, 600, and 700 ° C. for 5 hours, respectively. The magnetite powder after heating was measured for specific surface area by BET method and average particle diameter (D50) by laser diffraction method. 1 and 2 show X-ray diffraction spectra of magnetite powders obtained by heating at 300 ° C. and 400 ° C., respectively. When heated below 400 ° C., the oxide is only magnetite, but when heated above 400 ° C., hematite is precipitated. Further, from the relationship of the heating temperature and the specific surface area shown in FIG. 3, the specific surface area becomes considerably smaller in heating above 300 ° C., the at 600 ℃ 4m 2 / g or less. Therefore, it can be seen that heating at 600 ° C. or lower is necessary to obtain a specific surface area of 4 m 2 / g or higher. From the relationship between the average particle diameter and the heating temperature shown in FIG. 3, the average particle diameter tends to be slightly smaller as the heating temperature is increased.
（実施例３）
合金組成をミッシュメタル１０．８原子％、残部Ｆｅ、粉砕後の粒径を２４．２μｍとした以外は実施例１と同様にしてマグネタイトを製造した。ＩＣＰにより分析した結果、得られたマグネタイト粉末の組成はミッシュメタルの総量が１．３原子％、残部はＦｅであった。実施例１と同様に比表面積、平均粒子径（Ｄ５０）を測定したところ、比表面積は２５．５ｍ２／ｇ、平均粒子径１５．８μｍであった。またＸ線回折によりヘマタイトのピークは確認できなかった。(Example 3)
Magnetite was produced in the same manner as in Example 1 except that the alloy composition was 10.8 atomic% Misch metal, the remaining Fe, and the particle size after grinding was 24.2 μm. As a result of analysis by ICP, the composition of the obtained magnetite powder had a total amount of misch metal of 1.3 atomic%, and the balance was Fe. When the specific surface area and the average particle diameter (D50) were measured in the same manner as in Example 1, the specific surface area was 25.5 m 2 / g and the average particle diameter was 15.8 μm. Also, no hematite peak could be confirmed by X-ray diffraction.
（実施例４）
合金組成をミッシュメタル８．５原子％、残部Ｆｅ、粉砕後の粒径を２３．８μｍとした以外は実施例３と同様にしてマグネタイトを製造した。ＩＣＰにより分析した結果、得られたマグネタイト粉末の組成はミッシュメタルの総量が１．１原子％、残部はＦｅであった。実施例１と同様に比表面積、平均粒子径（Ｄ５０）を測定したところ、比表面積は２４．５ｍ２／ｇ、平均粒子径１６．８μｍであった。またＸ線回折によりヘマタイトのピークは確認できなかった。Example 4
Magnetite was produced in the same manner as in Example 3 except that the alloy composition was 8.5 atomic%, the balance was Fe, and the particle size after pulverization was 23.8 μm. As a result of analysis by ICP, the composition of the obtained magnetite powder was 1.1 atomic% in the total amount of misch metal, and the balance was Fe. When the specific surface area and the average particle diameter (D50) were measured in the same manner as in Example 1, the specific surface area was 24.5 m 2 / g and the average particle diameter was 16.8 μm. Also, no hematite peak could be confirmed by X-ray diffraction.
（実施例５）
５ｍｏｌ／ｌの水酸化ナトリウム水溶液１６００ｍｌを３ｍｏｌ／ｌの炭酸水素アンモニウム水溶液４０００ｍｌに変えた以外は実施例１と同様にしてマグネタイトを製造した。ＩＣＰにより分析した結果、得られたマグネタイト粉末の組成は１．５４Ｎｄ−０．６５Ｃｏ−１．４５Ｂ−９６．３６Ｆｅであった。実施例１と同様に比表面積、平均粒子径（Ｄ５０）を測定したところ、比表面積は１９．３ｍ２／ｇ、平均粒子径１８．３μｍであった。またＸ線回折によりヘマタイトのピークは確認できなかった。(Example 5)
Magnetite was produced in the same manner as in Example 1 except that 1600 ml of 5 mol / l sodium hydroxide aqueous solution was changed to 4000 ml of 3 mol / l ammonium hydrogen carbonate aqueous solution. As a result of analysis by ICP, the composition of the obtained magnetite powder was 1.54Nd-0.65Co-1.45B-96.36Fe. When the specific surface area and average particle size (D50) were measured in the same manner as in Example 1, the specific surface area was 19.3 m 2 / g and the average particle size was 18.3 μm. Also, no hematite peak could be confirmed by X-ray diffraction.
（実施例６）
５ｍｏｌ／ｌの水酸化ナトリウム水溶液１６００ｍｌを３ｍｏｌ／ｌの水酸化カリウム水溶液４０００ｍｌに変えた以外は実施例１と同様にしてマグネタイトを製造した。ＩＣＰにより分析した結果、得られたマグネタイト粉末の組成は１．３８Ｎｄ−０．７０Ｃｏ−０．４３Ｂ−９７．４９Ｆｅであった。実施例１と同様に比表面積、平均粒子径（Ｄ５０）を測定したところ、比表面積は１５．３ｍ２／ｇ、平均粒子径１４．１μｍであった。またＸ線回折によりヘマタイトのピークは確認できなかった。(Example 6)
Magnetite was produced in the same manner as in Example 1 except that 1600 ml of 5 mol / l sodium hydroxide aqueous solution was changed to 4000 ml of 3 mol / l potassium hydroxide aqueous solution. As a result of analysis by ICP, the composition of the obtained magnetite powder was 1.38Nd-0.70Co-0.43B-97.49Fe. When the specific surface area and average particle diameter (D50) were measured in the same manner as in Example 1, the specific surface area was 15.3 m 2 / g and the average particle diameter was 14.1 μm. Also, no hematite peak could be confirmed by X-ray diffraction.
（実施例７）
２ｍｏｌ／ｌの水酸化ナトリウム水溶液２５００ｍｌを３ｍｏｌ／ｌの炭酸水素アンモニウム水溶液４０００ｍｌに変えた以外は実施例２と同様にしてマグネタイトを製造した。得られたマグネタイト粉末を３００℃で５時間加熱した。ＩＣＰにより分析した結果、得られたマグネタイト粉末の組成は１．２２Ｎｄ−０．３１Ｄｙ−０．９９Ｃｏ−２．８Ｂ−９４．６８Ｆｅであった。実施例１と同様に比表面積、平均粒子径（Ｄ５０）を測定したところ、比表面積は１８．３ｍ２／ｇ、平均粒子径２０．１μｍであった。またＸ線回折によりヘマタイトのピークは確認できなかった。(Example 7)
Magnetite was produced in the same manner as in Example 2 except that 2500 ml of 2 mol / l sodium hydroxide aqueous solution was changed to 4000 ml of 3 mol / l ammonium hydrogen carbonate aqueous solution. The obtained magnetite powder was heated at 300 ° C. for 5 hours. As a result of analysis by ICP, the composition of the obtained magnetite powder was 1.22Nd-0.31Dy-0.99Co-2.8B-94.68Fe. When the specific surface area and average particle diameter (D50) were measured in the same manner as in Example 1, the specific surface area was 18.3 m 2 / g and the average particle diameter was 20.1 μm. Also, no hematite peak could be confirmed by X-ray diffraction.
（実施例８）
２ｍｏｌ／ｌの水酸化ナトリウム水溶液２５００ｍｌを３ｍｏｌ／ｌの水酸化カリウム水溶液４０００ｍｌに変えた以外は実施例２と同様にしてマグネタイトを製造した。得られたマグネタイト粉末を３００℃で５時間加熱した。ＩＣＰにより分析した結果、得られたマグネタイト粉末の組成は１．３３Ｎｄ−０．５０Ｄｙ−０．６７Ｃｏ−０．５０Ｂ−９７．００Ｆｅであった。実施例１と同様に比表面積、平均粒子径（Ｄ５０）を測定したところ、比表面積は２４．６ｍ２／ｇ、平均粒子径１６．５μｍであった。またＸ線回折によりヘマタイトのピークは確認できなかった。(Example 8)
Magnetite was produced in the same manner as in Example 2 except that 2500 ml of 2 mol / l sodium hydroxide aqueous solution was changed to 4000 ml of 3 mol / l potassium hydroxide aqueous solution. The obtained magnetite powder was heated at 300 ° C. for 5 hours. As a result of analysis by ICP, the composition of the obtained magnetite powder was 1.33Nd-0.50Dy-0.67Co-0.50B-97.00Fe. When the specific surface area and the average particle diameter (D50) were measured in the same manner as in Example 1, the specific surface area was 24.6 m 2 / g and the average particle diameter was 16.5 μm. Also, no hematite peak could be confirmed by X-ray diffraction.
（実施例９）
５ｍｏｌ／ｌの塩酸水溶液１５００ｍｌを２ｍｏｌ／ｌの硝酸水溶液３０００ｍｌに変えた以外は実施例２と同様にしてマグネタイトを製造した。得られたマグネタイト粉末を３００℃で５時間加熱した。ＩＣＰにより分析した結果、得られたマグネタイト粉末の組成は１．５３Ｎｄ−０．５０Ｄｙ−０．８８Ｃｏ−０．７０Ｂ−９６．６Ｆｅであった。実施例１と同様に比表面積、平均粒子径（Ｄ５０）を測定したところ、比表面積は２２．６ｍ２／ｇ、平均粒子径１７．２μｍであった。またＸ線回折によりヘマタイトのピークは確認できなかった。Example 9
Magnetite was produced in the same manner as in Example 2 except that 1500 ml of 5 mol / l hydrochloric acid aqueous solution was changed to 3000 ml of 2 mol / l nitric acid aqueous solution. The obtained magnetite powder was heated at 300 ° C. for 5 hours. As a result of analysis by ICP, the composition of the obtained magnetite powder was 1.53Nd-0.50Dy-0.88Co-0.70B-96.6Fe. When the specific surface area and the average particle diameter (D50) were measured in the same manner as in Example 1, the specific surface area was 22.6 m 2 / g and the average particle diameter was 17.2 μm. Also, no hematite peak could be confirmed by X-ray diffraction.
（実施例１０）
２ｍｏｌ／ｌの水酸化ナトリウム水溶液２５００ｍｌを３ｍｏｌ／ｌの水酸化カリウム水溶液４０００ｍｌ、５ｍｏｌ／ｌの塩酸水溶液１５００ｍｌを１ｍｏｌ／ｌの硝酸水溶液２０００ｍｌに変えた以外は実施例２と同様にしてマグネタイトを製造した。得られたマグネタイト粉末を３００℃で５時間加熱した。ＩＣＰにより分析した結果、得られたマグネタイト粉末の組成は１．５６Ｎｄ−０．５３Ｄｙ−０．６９Ｃｏ−０．４７Ｂ−９６．７５Ｆｅであった。実施例１と同様に比表面積、平均粒子径（Ｄ５０）を測定したところ、比表面積は２４．６ｍ２／ｇ、平均粒子径１５．４μｍであった。またＸ線回折によりヘマタイトのピークは確認できなかった。(Example 10)
Magnetite is produced in the same manner as in Example 2 except that 2500 ml of 2 mol / l sodium hydroxide aqueous solution is changed to 4000 ml of 3 mol / l potassium hydroxide aqueous solution and 1500 ml of 5 mol / l hydrochloric acid aqueous solution is changed to 2000 ml of 1 mol / l nitric acid aqueous solution. did. The obtained magnetite powder was heated at 300 ° C. for 5 hours. As a result of analysis by ICP, the composition of the obtained magnetite powder was 1.56Nd-0.53Dy-0.69Co-0.47B-96.75Fe. When the specific surface area and average particle diameter (D50) were measured in the same manner as in Example 1, the specific surface area was 24.6 m 2 / g and the average particle diameter was 15.4 μm. Also, no hematite peak could be confirmed by X-ray diffraction.
（比較例１）
平均粒子径０．３０μｍ、比表面積８．５ｍ２／ｇの市販のトナー用マグネタイト粉末を水素１００％の雰囲気中、６００℃の温度で４時間加熱した。還元処理した鉄粉を大気中に取り出すと発火した。(Comparative Example 1)
A commercially available magnetite powder for toner having an average particle size of 0.30 μm and a specific surface area of 8.5 m 2 / g was heated in a 100% hydrogen atmosphere at a temperature of 600 ° C. for 4 hours. When reduced iron powder was taken out into the atmosphere, it ignited.
Claims (9)
（工程１）Ｍ元素を含有する鉄を主成分とする合金（Ｆｅ−Ｍ合金）を準備する工程
（工程２Ａ）該Ｆｅ−Ｍ合金を酸溶液に浸漬し、Ｍ元素を溶出させ、鉄の水酸化物を主成分とする固形物（Ｆｅ固形物）を得る工程
（工程３Ａ）該Ｆｅ固形物をアルカリ溶液に浸漬し、マグネタイト粉末を得る工程The manufacturing method of the magnetite powder characterized by including the following process 1, 2A, 3A.
(Step 1) Step of preparing an iron-based alloy containing M element (Fe-M alloy) (Step 2A) The Fe-M alloy is immersed in an acid solution to elute M element, Step of obtaining a solid (Fe solid) containing hydroxide as a main component (Step 3A) Step of immersing the Fe solid in an alkaline solution to obtain a magnetite powder
（工程１）Ｍ元素を含有する鉄を主成分とする合金（Ｆｅ−Ｍ合金）を準備する工程
（工程２Ｂ）該Ｆｅ−Ｍ合金をアルカリ溶液に浸漬し、マグネタイトを主成分とする固形物（中間マグネタイト固形物）を得る工程
（工程３Ｂ）該中間マグネタイト固形物を酸溶液に浸漬し、Ｍ元素を溶出させ、マグネタイト粉末を得る工程The manufacturing method of the magnetite powder characterized by including the following process 1, 2B, 3B.
(Step 1) Step of preparing an iron-based alloy containing Fe element (Fe-M alloy) (Step 2B) A solid material containing magnetite as a main component by immersing the Fe-M alloy in an alkaline solution Step of obtaining (intermediate magnetite solid) (step 3B) Step of immersing the intermediate magnetite solid in an acid solution to elute M element to obtain magnetite powder
（工程４）該マグネタイト粉末を加熱する工程8. The method for producing a magnetite powder according to claim 4, wherein the following step 4 is performed after the step 3A or the step 3B.
(Step 4) Step of heating the magnetite powder
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| CN106920621A (en) * | 2017-04-16 | 2017-07-04 | 广州蓝磁新材料科技有限公司 | It is a kind of can self-passivation insulation iron-silicon-aluminum soft magnet alloy powder preparation method |
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