JPH0251429A - Production of spindle-shaped goethite particle powder - Google Patents
Production of spindle-shaped goethite particle powderInfo
- Publication number
- JPH0251429A JPH0251429A JP63202137A JP20213788A JPH0251429A JP H0251429 A JPH0251429 A JP H0251429A JP 63202137 A JP63202137 A JP 63202137A JP 20213788 A JP20213788 A JP 20213788A JP H0251429 A JPH0251429 A JP H0251429A
- Authority
- JP
- Japan
- Prior art keywords
- particles
- axis diameter
- spindle
- aqueous solution
- alkali
- 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
- 239000002245 particle Substances 0.000 title claims abstract description 100
- 229910052598 goethite Inorganic materials 0.000 title claims abstract description 51
- AEIXRCIKZIZYPM-UHFFFAOYSA-M hydroxy(oxo)iron Chemical compound [O][Fe]O AEIXRCIKZIZYPM-UHFFFAOYSA-M 0.000 title claims abstract description 51
- 238000004519 manufacturing process Methods 0.000 title claims description 10
- 239000000843 powder Substances 0.000 title abstract description 16
- 239000003513 alkali Substances 0.000 claims abstract description 28
- BVKZGUZCCUSVTD-UHFFFAOYSA-L Carbonate Chemical compound [O-]C([O-])=O BVKZGUZCCUSVTD-UHFFFAOYSA-L 0.000 claims abstract description 24
- 238000000034 method Methods 0.000 claims abstract description 23
- 239000007789 gas Substances 0.000 claims abstract description 17
- 230000032683 aging Effects 0.000 claims abstract description 16
- 229910001854 alkali hydroxide Inorganic materials 0.000 claims abstract description 15
- 150000008044 alkali metal hydroxides Chemical class 0.000 claims abstract description 15
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims abstract description 10
- 239000001301 oxygen Substances 0.000 claims abstract description 10
- 229910052760 oxygen Inorganic materials 0.000 claims abstract description 10
- 230000001590 oxidative effect Effects 0.000 claims abstract description 9
- 239000007864 aqueous solution Substances 0.000 claims description 31
- BAUYGSIQEAFULO-UHFFFAOYSA-L iron(2+) sulfate (anhydrous) Chemical compound [Fe+2].[O-]S([O-])(=O)=O BAUYGSIQEAFULO-UHFFFAOYSA-L 0.000 claims description 13
- 230000001747 exhibiting effect Effects 0.000 claims description 8
- 239000012266 salt solution Substances 0.000 claims description 6
- XEEYBQQBJWHFJM-UHFFFAOYSA-N iron Substances [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 abstract description 15
- CWYNVVGOOAEACU-UHFFFAOYSA-N Fe2+ Chemical compound [Fe+2] CWYNVVGOOAEACU-UHFFFAOYSA-N 0.000 abstract description 7
- 229910000015 iron(II) carbonate Inorganic materials 0.000 abstract description 4
- 238000007664 blowing Methods 0.000 abstract description 2
- 238000006243 chemical reaction Methods 0.000 description 12
- 239000006249 magnetic particle Substances 0.000 description 9
- SZVJSHCCFOBDDC-UHFFFAOYSA-N iron(II,III) oxide Inorganic materials O=[Fe]O[Fe]O[Fe]=O SZVJSHCCFOBDDC-UHFFFAOYSA-N 0.000 description 8
- 230000000052 comparative effect Effects 0.000 description 7
- 238000007254 oxidation reaction Methods 0.000 description 7
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 6
- 239000007858 starting material Substances 0.000 description 6
- 238000000635 electron micrograph Methods 0.000 description 5
- 230000003647 oxidation Effects 0.000 description 5
- 229910052742 iron Inorganic materials 0.000 description 4
- 239000000696 magnetic material Substances 0.000 description 4
- KWYUFKZDYYNOTN-UHFFFAOYSA-M Potassium hydroxide Chemical compound [OH-].[K+] KWYUFKZDYYNOTN-UHFFFAOYSA-M 0.000 description 3
- 239000011248 coating agent Substances 0.000 description 3
- 238000000576 coating method Methods 0.000 description 3
- 239000013078 crystal Substances 0.000 description 3
- 238000005516 engineering process Methods 0.000 description 3
- 239000011790 ferrous sulphate Substances 0.000 description 3
- 235000003891 ferrous sulphate Nutrition 0.000 description 3
- 229910000359 iron(II) sulfate Inorganic materials 0.000 description 3
- JEIPFZHSYJVQDO-UHFFFAOYSA-N iron(III) oxide Inorganic materials O=[Fe]O[Fe]=O JEIPFZHSYJVQDO-UHFFFAOYSA-N 0.000 description 3
- 230000005415 magnetization Effects 0.000 description 3
- 239000002244 precipitate Substances 0.000 description 3
- 230000035945 sensitivity Effects 0.000 description 3
- UQSXHKLRYXJYBZ-UHFFFAOYSA-N Iron oxide Chemical compound [Fe]=O UQSXHKLRYXJYBZ-UHFFFAOYSA-N 0.000 description 2
- CDBYLPFSWZWCQE-UHFFFAOYSA-L Sodium Carbonate Chemical compound [Na+].[Na+].[O-]C([O-])=O CDBYLPFSWZWCQE-UHFFFAOYSA-L 0.000 description 2
- 238000002441 X-ray diffraction Methods 0.000 description 2
- 238000005273 aeration Methods 0.000 description 2
- 230000007423 decrease Effects 0.000 description 2
- 230000018109 developmental process Effects 0.000 description 2
- 239000007788 liquid Substances 0.000 description 2
- 239000006247 magnetic powder Substances 0.000 description 2
- 238000002156 mixing Methods 0.000 description 2
- BWHMMNNQKKPAPP-UHFFFAOYSA-L potassium carbonate Chemical compound [K+].[K+].[O-]C([O-])=O BWHMMNNQKKPAPP-UHFFFAOYSA-L 0.000 description 2
- 239000011734 sodium Substances 0.000 description 2
- 238000003756 stirring Methods 0.000 description 2
- ATRRKUHOCOJYRX-UHFFFAOYSA-N Ammonium bicarbonate Chemical compound [NH4+].OC([O-])=O ATRRKUHOCOJYRX-UHFFFAOYSA-N 0.000 description 1
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 1
- 239000012670 alkaline solution Substances 0.000 description 1
- 239000001099 ammonium carbonate Substances 0.000 description 1
- 235000012501 ammonium carbonate Nutrition 0.000 description 1
- BVKZGUZCCUSVTD-UHFFFAOYSA-N carbonic acid Chemical compound OC(O)=O BVKZGUZCCUSVTD-UHFFFAOYSA-N 0.000 description 1
- 229910052804 chromium Inorganic materials 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 229960002089 ferrous chloride Drugs 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 239000001257 hydrogen Substances 0.000 description 1
- 229910052739 hydrogen Inorganic materials 0.000 description 1
- 239000011261 inert gas Substances 0.000 description 1
- 230000003993 interaction Effects 0.000 description 1
- NMCUIPGRVMDVDB-UHFFFAOYSA-L iron dichloride Chemical compound Cl[Fe]Cl NMCUIPGRVMDVDB-UHFFFAOYSA-L 0.000 description 1
- 229910021506 iron(II) hydroxide Inorganic materials 0.000 description 1
- NCNCGGDMXMBVIA-UHFFFAOYSA-L iron(ii) hydroxide Chemical compound [OH-].[OH-].[Fe+2] NCNCGGDMXMBVIA-UHFFFAOYSA-L 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
- 229910052759 nickel Inorganic materials 0.000 description 1
- 229910000027 potassium carbonate Inorganic materials 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 230000005070 ripening Effects 0.000 description 1
- 229910000029 sodium carbonate Inorganic materials 0.000 description 1
- 239000000243 solution Substances 0.000 description 1
- 239000000725 suspension Substances 0.000 description 1
- 238000009423 ventilation Methods 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
- 229910052725 zinc Inorganic materials 0.000 description 1
Landscapes
- Hard Magnetic Materials (AREA)
- Compounds Of Iron (AREA)
- Magnetic Record Carriers (AREA)
Abstract
Description
【発明の詳細な説明】
〔産業上の利用分野〕
本発明は、磁気記録用磁性材料粒子粉末を製造する際の
出発原料として使用される紡錘形を呈したゲータイト粒
子粉末の製造法に関するものであり、詳しくは、高濃度
の反応が可能で、且つ、紡錘形を呈したゲータイト粒子
の生成にあたって使用する原料のうち最も高価なアルカ
リ性水溶液の鉄に対する使用割合を少なくすることが可
能であり、しかも、熟成工程におけるエネルギー量（時
間と温度との関係で示される。）の節減が可能であるこ
とに起因して生産性を高めることができる省資源、省エ
ネルギーの反応によって、軸比（長軸径／短軸径）が大
きい紡錘形を呈したゲータイト粒子を工業的、経済的に
有利に提供することを目的とする。[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for producing spindle-shaped goethite particles used as a starting material in producing magnetic material particles for magnetic recording. Specifically, it is possible to perform a reaction at a high concentration, and it is possible to reduce the ratio of iron to the alkaline aqueous solution, which is the most expensive raw material used in the production of spindle-shaped goethite particles. The axial ratio (major axis diameter/short axis diameter) increases through resource-saving and energy-saving reactions that can increase productivity by reducing the amount of energy (expressed in the relationship between time and temperature) in the process. The purpose of the present invention is to provide goethite particles exhibiting a spindle shape with a large axis diameter, which is industrially and economically advantageous.
近年、磁気記録再生用機器の小型軽量化が進むにつれて
、磁気テープ、磁気ディスク等の記録媒体に対する高性
能化の必要性が益々生じてきている。In recent years, as magnetic recording and reproducing equipment has become smaller and lighter, there has been an increasing need for higher performance recording media such as magnetic tapes and magnetic disks.
即ち、高記録密度、高感度特性及び高出力特性等が要求
される。That is, high recording density, high sensitivity characteristics, high output characteristics, etc. are required.
磁気記録媒体に対する上記のような要求を満足させる為
に要求される磁性材料粒子粉末の特性は、高い保磁力と
優れた分散性を有することである。In order to satisfy the above-mentioned requirements for magnetic recording media, the characteristics required for magnetic material particles are high coercive force and excellent dispersibility.
即ち、磁気記録媒体の高感度化及び高出力化の為には、
磁性粒子粉末が出来るだけ高い保磁力を有することが必
要であり、この事実は、例えば、株式会社総合技術セン
ター発行「磁性材料の開発と磁粉の高分散化技術Ｊ
（１９８２年）の第３１０頁の「磁気テープ性能の向上
上向は、高感度化と高出力化・・・・にあったから、針
状γ−Ｆｅｚ０３粒子粉末の高保磁力化・・・・を重点
とするものであった。」なる記載から明らかである。In other words, in order to increase the sensitivity and output of magnetic recording media,
It is necessary for the magnetic particles to have as high a coercive force as possible, and this fact can be seen, for example, in "Development of Magnetic Materials and Highly Dispersed Magnetic Powder Technology J.
(1982), p. 310, ``The improvement in magnetic tape performance has been due to higher sensitivity and higher output... so we have developed acicular γ-Fez03 particles with higher coercive force... This is clear from the statement, ``This was a priority.''
また、磁気記録媒体の高記録密度の為には、前出「磁性
材料の開発と磁粉の高分散化技術」第３１２頁の「塗布
型テープにおける高密度記録のための条件は、短波長信
号に対して、低ノイズで高出力特性を保持できることで
あるが、その為には保磁力Ｈｅと残留磁化Ｂｒが共に大
きいことと塗布膜の厚みがより薄いことが必要である。In addition, in order to achieve high recording density in magnetic recording media, the conditions for high-density recording in coated tapes, as described in the aforementioned "Development of Magnetic Materials and Highly Dispersed Magnetic Powder Technology" on page 312, are as follows: On the other hand, it is possible to maintain high output characteristics with low noise, but for this purpose, it is necessary that both the coercive force He and the residual magnetization Br be large, and that the thickness of the coating film be thinner.
Ｊなる記載の通り、磁気記録媒体が高い保磁力と大きな
残留磁化Ｂｒを有することが必要であり、その為には磁
性粒子粉末が高い保磁力を有し、ビークル中での分散性
、塗膜中での配向性及び充填性が優れていることが要求
される。As stated in J, it is necessary for the magnetic recording medium to have a high coercive force and a large residual magnetization Br, and for this purpose, the magnetic particle powder must have a high coercive force, and the dispersibility in the vehicle and the coating film are Excellent orientation and filling properties are required.
磁気記録媒体の残留磁化Ｂｒは、磁性粒子粉末のビーク
ル中での分散性、塗膜中での配向性及び充填性に依存し
ており、これら特性の向上の為には、ビークル中に分散
させる磁性粒子粉末ができるだけ大きな軸比（長軸径／
短軸径）を有し、しかも粒度が均斉であって、樹枝状粒
子が混在していないことが要求される。The residual magnetization Br of a magnetic recording medium depends on the dispersibility of the magnetic particles in the vehicle, the orientation and filling properties in the coating film, and in order to improve these properties, it is necessary to disperse them in the vehicle. Magnetic particle powder has as large an axial ratio as possible (major axis diameter/
It is required that the particle size is uniform, and that dendritic particles are not mixed therein.
また周知のごとく、磁性粒子粉末の保磁力の大きさは、
形状異方性、結晶異方性、全異方性及び交換異方性のい
ずれか、若しくはそれらの相互作用に依存している。Also, as is well known, the magnitude of the coercive force of magnetic particles is
It depends on shape anisotropy, crystal anisotropy, total anisotropy, exchange anisotropy, or their interaction.
現在、磁気記録用磁性粒子粉末として使用されている針
状晶マグネタイト粒子粉末、又は、針状晶マグヘマイト
粒子粉末は、その形状に由来する異方性を利用すること
、即ち、軸比（長軸径／短軸径）を大きくすることによ
って比較的高い保磁力を得ている。Currently, acicular magnetite particles or acicular maghemite particles, which are currently used as magnetic particles for magnetic recording, utilize the anisotropy derived from their shape, that is, the axial ratio (long axis A relatively high coercive force is obtained by increasing the diameter (diameter/short axis diameter).
これら既知の針状晶マグネタイト粒子粉末、又は、針状
晶マグヘマイト粒子粉末は、出発原料であるゲータイト
粒子を、水素等還元性ガス中３００〜４００℃で還元し
てマグネタイト粒子とし、または次いでこれを、空気中
２００〜３００℃で酸化してマグヘマイト粒子とするこ
とにより得られている。These known acicular crystal magnetite particles or acicular crystal maghemite particles are obtained by reducing goethite particles as a starting material at 300 to 400°C in a reducing gas such as hydrogen to obtain magnetite particles, or by reducing the starting material to magnetite particles. It is obtained by oxidizing it in air at 200 to 300°C to form maghemite particles.
上述した通り、粒度が均斉であって、樹枝状粒子が混在
しておらず、しかも軸比Ｃ長軸径／短軸径）が大きい磁
性粒子粉末は、現在、最も要求されているところであり
、このような特性を備えた磁性粒子粉末を得るためには
、出発原料であるゲータイト粒子粉末の粒度が均斉であ
って、樹枝状粒子が混在しておらず、しかも、軸比（長
軸径／短軸径）が大きいことが必要である。As mentioned above, magnetic particle powders with uniform particle size, no dendritic particles mixed in, and a large axial ratio (major axis diameter/minor axis diameter) are currently in greatest demand. In order to obtain magnetic particles with such characteristics, the particle size of the starting material, goethite particles, must be uniform, dendritic particles are not mixed, and the axial ratio (major axis diameter / It is necessary that the short axis diameter) be large.
一方、近年、省責源、省エネルギー化の要請が益々強ま
っており、ゲータイト粒子粉末の生成にあたっても同様
であり、工業的、経済的に有利にゲータイト粒子を得る
ことが強く要望されている。On the other hand, in recent years, there has been an increasing demand for resource saving and energy saving, and the same applies to the production of goethite particles, and there is a strong demand for obtaining goethite particles that are industrially and economically advantageous.
従来、出発原料であるゲータイト粒子粉末を製造する方
法としては、第一鉄塩溶液に当量以上のアルカリ性溶液
を加えて得られる水酸化第一鉄粒子を含む溶液をｐＨ１
１以上にて８０℃以下の温度で酸素含有ガスを通気して
酸化反応を行うことにより針状ゲータイト粒子を生成さ
せる方法、及び、第一鉄塩水溶液と炭酸アルカリとを反
応させて得られたＦｅＣＯ３を含む水溶液に酸素含有ガ
スを通気して酸化反応を行うことにより紡錘状を呈した
ゲータイト粒子を生成させる方法等が知られている。Conventionally, as a method for producing goethite particle powder, which is a starting material, a solution containing ferrous hydroxide particles obtained by adding an equivalent or more alkaline solution to a ferrous salt solution is adjusted to pH 1.
A method of producing acicular goethite particles by performing an oxidation reaction by passing an oxygen-containing gas at a temperature of 1 or more and 80°C or less, and a method of producing acicular goethite particles by reacting an aqueous ferrous salt solution with an alkali carbonate. A method is known in which spindle-shaped goethite particles are produced by passing an oxygen-containing gas through an aqueous solution containing FeCO3 to perform an oxidation reaction.
粒度が均斉であって、樹枝状粒子が混在しておらず、し
かも軸比（長軸径／短軸径）の大きい磁性粒子粉末を工
業的、経済的に有利に得ることは、現在、最も要求され
ているところであるが、出発原料であるゲータイト粒子
粉末を製造する前述公知方法のうち前者の方法による場
合には、軸比（長軸径／短軸径）の大きな殊に、１０以
上の針状晶ゲータイト粒子が生成するが、樹枝状粒子が
混在しており、また、粒度から言えば、均斉な粒度を有
した粒子とは言い難い。Currently, it is the most desirable industrially and economically advantageous method to obtain magnetic particles with uniform particle size, no dendritic particles mixed therein, and a large axial ratio (major axis diameter/minor axis diameter). Although it is required, in the case of the former method among the above-mentioned known methods for producing goethite particles as a starting material, the axial ratio (major axis diameter/minor axis diameter) is large, especially 10 or more. Although acicular goethite particles are produced, dendritic particles are mixed therein, and in terms of particle size, it is difficult to say that the particles have a uniform particle size.
前述公知方法のうち後者の方法による場合には、粒度が
均斉であり、また、樹枝状粒子が混在していない紡錘形
を呈した粒子が生成するが、一方、軸比（長軸径／短軸
径）は高々７程度であり、軸比（長軸径／短軸径）の大
きな粒子が生成し難いという欠点があり、殊に、この現
象は生成粒子の長軸径が小さ（なる程顕著になるという
傾向にある。In the case of the latter method among the above-mentioned known methods, spindle-shaped particles with uniform particle size and no dendritic particles are produced; diameter) is about 7 at most, and there is a drawback that it is difficult to produce particles with a large axial ratio (major axis diameter / minor axis diameter).This phenomenon is especially noticeable when the major axis diameter of the produced particles is small There is a tendency to become
従来、紡錘形を呈したゲータイト粒子の軸比（長軸径／
短軸径）を大きくする方法は種々試みられており、例え
ば特開昭５９−２３２９２２号公報に開示されている第
一鉄塩水溶液と炭酸アルカリとを反応させて得られたＦ
ｅＣＯ３を含む水溶液に酸素含有ガスを通気するにあた
り、酸素含有ガスの通気速度を０．１〜２．０ｃｍ／ｓ
ｅｅ程度に遅くするという方法がある。この方法による
ときには、０．５μ園程度の場合における軸比（長軸径
／短軸径）はｌＯ程度、長軸径０．３μｍ程度の場合に
おける軸比（長軸径／短軸径）は８程度であり、更に長
軸径が小さくなって０．０５μ端程度になると軸比（長
軸径／短軸径）は５程度と小さくなってしまい、未だ軸
比（長軸径／短軸径）が十分大きなものとは言い難い。Conventionally, the axial ratio (major axis diameter/
Various methods have been tried to increase the short axis diameter (short axis diameter).For example, F
When aerating an oxygen-containing gas into an aqueous solution containing eCO3, the aeration rate of the oxygen-containing gas is set at 0.1 to 2.0 cm/s.
There is a method of slowing down to about ee. When using this method, the axial ratio (major axis diameter/minor axis diameter) when the diameter is about 0.5 μm is about 1O, and the axial ratio (major axis diameter / short axis diameter) when the long axis diameter is about 0.3 μm. 8, and when the major axis diameter becomes smaller and reaches the 0.05μ end, the axial ratio (major axis diameter/minor axis diameter) decreases to approximately 5, and the axial ratio (major axis diameter/minor axis diameter) still decreases to about 5. It is difficult to say that the diameter) is sufficiently large.
また、特開昭６２−１５８８０１号公報の実施例におい
て、軸比（長軸径／短軸径〕が１０の紡錘形を呈したゲ
ータイト粒子が得られているが、これは、鉄濃度を０．
２ ｍｏｌ＃！程度と薄くすることにより得られたもの
であり、工業的、経済的とは言えず、また、未だ軸比（
長軸径／短軸径）が十分大きなものとは言い難い。Further, in the example of JP-A No. 62-158801, spindle-shaped goethite particles with an axial ratio (major axis diameter/minor axis diameter) of 10 are obtained, but these particles have an iron concentration of 0.
2 mol#! However, it is not industrially or economically viable, and the axial ratio (
It is difficult to say that the long axis diameter/short axis diameter) is sufficiently large.
本発明者は、粒度が均斉であって、樹枝状粒子が混在し
ておらず、しかも、軸比（長軸径／短軸径）が大きい紡
錘形を呈したゲータイト粒子粉末を得るべく種々検討を
重ね、炭酸アルカリと第一鉄塩水溶液とを反応させて得
られたＦｅＣＯ５を含む水溶液を非酸化性雰囲気下にお
いて熟成した後、該ＰｅＣ０、を含む水溶液中に酸素含
有ガスを通気して酸化することにより紡錘形を呈したゲ
ータイト粒子粉末を生成させる方法において、前記炭酸
アルカリの量を前記第一鉄塩水溶液中のＦｅに対し１゜
５〜３．５倍当量とするとともに、前記熟成における熟
成温度を４０〜６０℃且つ熟成時間を５０〜１００分間
とした場合には、長軸径が０．０５〜０．８ μ−であ
って、軸比（長軸径／短軸径）が１１以上である紡錘形
を呈したゲータイト粒子からなるゲータイト粒子粉末を
得ることができるという知見を既に得ている（特願昭６
２−２７２５２２号）、。The present inventor conducted various studies in order to obtain goethite particle powder that has a uniform particle size, does not contain dendritic particles, and has a spindle shape with a large axial ratio (major axis diameter/minor axis diameter). After aging an aqueous solution containing FeCO obtained by reacting an alkali carbonate and an aqueous ferrous salt solution in a non-oxidizing atmosphere, oxygen-containing gas is passed through the aqueous solution containing PeCO to oxidize it. In the method of producing spindle-shaped goethite particles, the amount of the alkali carbonate is 1.5 to 3.5 times the equivalent of Fe in the ferrous salt aqueous solution, and the aging temperature in the aging is When the temperature is 40 to 60°C and the aging time is 50 to 100 minutes, the long axis diameter is 0.05 to 0.8 μ-, and the axial ratio (major axis diameter / short axis diameter) is 11 or more. We have already obtained the knowledge that it is possible to obtain goethite particle powder consisting of goethite particles exhibiting a spindle shape (patent application published in 1983).
2-272522).
しかし、この方法による場合には、反応濃度が高々０．
４５ｍｏｌ／ １程度であり、また、アルカリの使用量
並びにエネルギー量等の生産性の面で未だ十分であると
は言い難いものであった。However, in this method, the reaction concentration is at most 0.
The amount was about 45 mol/1, and it was still far from being sufficient in terms of productivity such as the amount of alkali used and the amount of energy.
そこで、省資源、省エネルギーの反応によって軸比（長
軸径／短軸径）の大きな紡錘形を呈したゲータイト粒子
を工業的、経済的に有利に得る為の技術手段の確立が強
く要求されている。Therefore, there is a strong need to establish technical means to industrially and economically advantageously obtain spindle-shaped goethite particles with a large axial ratio (major axis diameter/minor axis diameter) through resource-saving and energy-saving reactions. .
本発明者は、省資源、省エネルギーの反応によって軸比
（長軸径／短軸径）の大きな紡錘形を呈したゲータイト
粒子粉末を工業的、経済的にを利に得るべく種々検討を
重ねた結果、本発明に到達してのである。The inventor of the present invention has conducted various studies in order to industrially and economically obtain a spindle-shaped goethite particle powder with a large axial ratio (major axis diameter/minor axis diameter) due to resource-saving and energy-saving reactions. , we have arrived at the present invention.
即ち、本発明は、炭酸アルカリと第一鉄塩水溶液とを反
応させて得られたＰｅＣＯ５を含む水溶液を非酸化性雰
囲気下において熟成した後、該ＦｅＣ０゜を含む水溶液
中に酸素含有ガスを通気して酸化することにより紡錘形
を呈したゲータイト粒子粉末を生成させる方法において
、前記炭酸アルカリ、前記ＦｅＣ０ｚを含む水溶液及び
熟成を行わせている前記ＦｅＣ０，を含む水溶液のいず
れかの液中に前記炭酸アルカリに対し１〜５０％の水酸
化アルカリを添加することにより、炭酸アルカリ及び水
酸化アルカリの総和量が前記第一鉄塩水溶液中のＦｅ２
＋に対し１．１〜２．５倍当量とするとともに、前記熟
成における熟成温度を３０〜６０℃且つ熟成時間を１０
〜ｌＯＯ分間とすることからなる紡錘形を呈したゲータ
イト粒子粉末の製造法である。That is, in the present invention, an aqueous solution containing PeCO5 obtained by reacting an alkali carbonate with an aqueous ferrous salt solution is aged in a non-oxidizing atmosphere, and then an oxygen-containing gas is bubbled into the aqueous solution containing FeCO. In the method of producing spindle-shaped goethite particles by oxidation, the carbonic acid is added to any one of the alkali carbonate, the aqueous solution containing the FeC0z, and the aqueous solution containing the FeC0 that is being aged. By adding 1 to 50% alkali hydroxide to the alkali, the total amount of alkali carbonate and alkali hydroxide can be reduced to Fe2 in the ferrous salt aqueous solution.
1.1 to 2.5 times equivalent to
This is a method for producing goethite particles exhibiting a spindle shape, which comprises making the powder for ~100 minutes.
先ず、本発明において最も重要な点は、炭酸アルカリと
第一鉄塩水溶液とを反応させて得られたＦｅＣＯ５を含
む水溶液を非酸化性雰囲気下において熟成した後、該Ｆ
ｅＣＯ３を含む水溶液中に酸素含有ガスを通気して酸化
することにより紡錘形を呈したゲータイト粒子粉末を生
成させる方法において、前記炭酸アルカリと共に水酸化
アルカリを併用した場合には、高濃度の反応が可能で、
且つ、高価なアルカリ性水溶液の鉄に対する使用割合を
少なくすることが可能であり、しかも、熟成工程におけ
るエネルギー量の節減が可能となるという事実である。First, the most important point in the present invention is that an aqueous solution containing FeCO5 obtained by reacting an alkali carbonate with an aqueous ferrous salt solution is aged in a non-oxidizing atmosphere, and then the F
In the method of producing spindle-shaped goethite particle powder by passing an oxygen-containing gas into an aqueous solution containing eCO3 for oxidation, a high concentration reaction is possible when an alkali hydroxide is used in combination with the alkali carbonate. in,
In addition, it is possible to reduce the ratio of expensive alkaline aqueous solution to iron, and it is also possible to save the amount of energy in the aging process.
本発明における水酸化アルカリの使用割合は、炭酸アル
カリに対し規定換算で１〜５０％である。The ratio of alkali hydroxide used in the present invention is 1 to 50% based on the standard value of alkali carbonate.
本発明においては、反応濃度が１．０ｓｏｌ／ Ｉｌ程
度まで可能である。In the present invention, the reaction concentration can be up to about 1.0 sol/Il.
本発明においては、炭酸アルカリと水酸化アルカリの総
和量がＦｅ２＋に対し１．１〜２．５倍当量で軸比（長
軸径／短軸径）が大きい紡錘形を呈したゲータイト粒子
を得ることができる。In the present invention, it is possible to obtain spindle-shaped goethite particles in which the total amount of alkali carbonate and alkali hydroxide is 1.1 to 2.5 times equivalent to Fe2+, and the axial ratio (major axis diameter/minor axis diameter) is large. Can be done.
本発明においては、炭酸アルカリを単独で使用する場合
に比べ、熟成温度を１０℃程度下げた場合にも、また、
熟成時間を４０分間程度短縮した場合にも、本発明の目
的とする軸比（長軸径／短軸径）が大きい紡錘形を呈し
たゲータイト粒子を得ることができる。In the present invention, even when the aging temperature is lowered by about 10°C compared to when alkali carbonate is used alone,
Even when the aging time is shortened by about 40 minutes, goethite particles exhibiting a spindle shape with a large axial ratio (major axis diameter/minor axis diameter), which is the objective of the present invention, can be obtained.
尚、ＦｅＣ０，を含む水溶液を非酸化性雰囲気下で熟成
するものとして、例えば、特公昭５９−４８７６８号公
報に開示されている方法があるが、この方法は、炭酸ア
ルカリの量をＰａに対し１．０６倍量として生成したＦ
ｅＣＯ２を含む水溶液を非酸化性雰囲気下、室温におい
て１２０〜２４０分間処理することにより粒度の均斉な
紡錘状を呈したゲータイト粒子粉末を得るものであり、
軸比（長軸径／短軸径）の大きい紡錘形を呈したゲータ
イト粒子粉末を得るものではない。For example, there is a method disclosed in Japanese Patent Publication No. 59-48768, in which an aqueous solution containing FeC0 is aged in a non-oxidizing atmosphere. F produced as 1.06 times the amount
By treating an aqueous solution containing eCO2 in a non-oxidizing atmosphere at room temperature for 120 to 240 minutes, goethite particle powder having a spindle shape with uniform particle size is obtained,
It is not possible to obtain goethite particles having a spindle shape with a large axis ratio (major axis diameter/minor axis diameter).
因に、特公昭５９−４８７６８号公報に記載の方法によ
って得られる紡錘形を呈したゲータイト粒子粉末の軸比
（長軸径／短軸径）は、「実施例１」及び「実施例２」
の各実施例において、４程度である。Incidentally, the axis ratio (major axis diameter/minor axis diameter) of the spindle-shaped goethite particles obtained by the method described in Japanese Patent Publication No. 59-48768 is that of "Example 1" and "Example 2".
In each example, it is about 4.
次に、本発明方法実施にあたっての諸条件について述べ
る。Next, various conditions for implementing the method of the present invention will be described.
本発明において使用される第一鉄塩水溶液としては、硫
酸第一鉄水溶液、塩化第−鉄水溶液等がある。Examples of the ferrous salt aqueous solution used in the present invention include a ferrous sulfate aqueous solution and a ferrous chloride aqueous solution.
本発明において使用される炭酸アルカリとしては、炭酸
ナトリウム、炭酸カリウム、炭酸アンモニウム等を使用
することができる。As the alkali carbonate used in the present invention, sodium carbonate, potassium carbonate, ammonium carbonate, etc. can be used.
本発明において使用される水酸化アルカリとしては、水
酸化ナトリウム、水酸化カリウム等を使用することがで
きる。As the alkali hydroxide used in the present invention, sodium hydroxide, potassium hydroxide, etc. can be used.
水酸化アルカリの添加時期は、炭酸アルカリ、ＦｅＣＯ
５を含む水溶液及び熟成を行わせているＰｅＣＯ５を含
む水溶液のいずれの液中に添加してもよく、いずれの場
合でも、本発明の目的を達成することができる。When adding alkali hydroxide, alkali carbonate, FeCO
It may be added to either an aqueous solution containing PeCO5 or an aqueous solution containing aged PeCO5, and in either case, the object of the present invention can be achieved.
水酸化アルカリの添加量は、炭酸アルカリに対し規定換
算で１〜５０％である。The amount of alkali hydroxide added is 1 to 50% based on the standard value of alkali carbonate.
１％以下の場合には、本発明の目的を達成することが困
難である。５０％以上である場合には、紡錘形を呈した
ゲータイト粒子中に粒状を呈したマグネタイト粒子が混
在してくる。If it is less than 1%, it is difficult to achieve the object of the present invention. When it is 50% or more, granular magnetite particles are mixed in spindle-shaped goethite particles.
本発明において使用する炭酸アルカリ及び水酸化アルカ
リの総和量は、第一鉄塩水溶液中のＦｅに対し１．１〜
２．５倍当量である。１．１倍当量以下の場合には、紡
錘形を呈したゲータイト粒子中に粒状を呈したマグネタ
イト粒子が混在してくる。２゜５倍当量以上の場合には
、高価なアルカリの使用量が多くなり、経済的ではない
。The total amount of alkali carbonate and alkali hydroxide used in the present invention is 1.1 to
It is 2.5 times equivalent. When the amount is 1.1 times or less, granular magnetite particles are mixed in spindle-shaped goethite particles. When the amount is 2.5 times or more, the amount of expensive alkali used increases, which is not economical.
本発明における熟成は、Ｎ２ガス等の不活性ガスを液中
に通気することにより不活性雰囲気下において行い、ま
た、当該通気ガスや機械的操作等により撹拌しながら行
う。Aging in the present invention is carried out in an inert atmosphere by passing an inert gas such as N2 gas into the liquid, and is carried out while stirring using the aeration gas or mechanical operation.
本発明における熟成温度は３０〜６０℃である。３０℃
以下の場合には、軸比（長軸径／短軸径）が小さくなり
、軸比（長軸径／短軸径）の大きい紡錘形を呈したゲー
タイト粒子粉末が得られない。６０゛Ｃ以上の場合でも
、軸比（長軸径／短軸径）の大きい紡錘形を呈したゲー
タイト粒子粉末を得ることができるが、必要以上に熟成
温度を上げる意味がない。The aging temperature in the present invention is 30 to 60°C. 30℃
In the following cases, the axial ratio (major axis diameter/minor axis diameter) becomes small, and goethite particle powder exhibiting a spindle shape with a large axial ratio (major axis diameter/minor axis diameter) cannot be obtained. Although it is possible to obtain spindle-shaped goethite particles with a large axial ratio (major axis diameter/minor axis diameter) even when the temperature is 60°C or higher, there is no point in raising the ripening temperature more than necessary.
本発明における熟成時間は、１０〜１００分間である。The aging time in the present invention is 10 to 100 minutes.
１０分以下の場合には、軸比（長軸径／短軸径）の大き
い紡錘形を呈したゲータイト粒子粉末を得ることができ
ない。１００分以上の場合にも軸比（長軸径／短軸径）
の大きい紡錘形を呈したゲータイト粒子粉末を得ること
ができるが必要以上に長時間とする意味がない。If the heating time is 10 minutes or less, goethite particles having a spindle shape with a large axis ratio (major axis diameter/minor axis diameter) cannot be obtained. Axial ratio (major axis diameter/minor axis diameter) even for 100 minutes or more
Although it is possible to obtain goethite particles exhibiting a large spindle shape, there is no point in using a longer time than necessary.
本発明の酸化時における反応温度は、３０〜７０℃であ
る。３０℃以下である場合には、軸比（長軸径／短軸径
）の大きい紡錘形を呈したゲータイト粒子粉末を得るこ
とができない。７０℃以上である場合には、紡錘形を呈
したゲータイト粒子中に粒状へマグイト粒子粉末が混在
してくる。The reaction temperature during oxidation of the present invention is 30 to 70°C. If the temperature is 30° C. or lower, goethite particles having a spindle shape with a large axis ratio (major axis diameter/minor axis diameter) cannot be obtained. When the temperature is 70° C. or higher, granular hemagite particles are mixed in the spindle-shaped goethite particles.
本発明におけるｐｏは７〜１１である。７以下、又は１
１以上である場合には、紡錘形を呈したゲータイト粒子
を得ることができない。po in the present invention is 7-11. 7 or less, or 1
If the number is 1 or more, spindle-shaped goethite particles cannot be obtained.
本発明における酸化手段は、酸素含有ガス（例えば空気
）を液中に通気することにより行い、また、当該通気ガ
スや機械的操作等により撹拌しながら行う。The oxidation means in the present invention is carried out by aerating an oxygen-containing gas (for example, air) into the liquid, and is carried out while stirring with the aerated gas or mechanical operation.
本発明においては、従来から磁性酸化鉄粒子粉末の各種
特性の向上の為に、出発原料ゲータイト粒子の生成に際
し、通常添加されるＣｏ、 Ｎｉ、 Ｃｒ、Ｚｎ、＾ｌ
ＳＭｎ等のＦｅ以外の異種金属を添加することができ、
この場合にも、本発明の目的を十分達成することができ
る。In the present invention, in order to improve various properties of magnetic iron oxide particles, Co, Ni, Cr, Zn, and
Different metals other than Fe such as SMn can be added,
In this case as well, the object of the present invention can be fully achieved.
次に、実施例並びに比較例により、本発明を説明する。 Next, the present invention will be explained with reference to Examples and Comparative Examples.
尚、以下の実施例並びに比較例における粒子の長軸径、
軸比（長軸径／短軸径）は、いずれも電子顕微鏡写真か
ら測定した数値の平均値で示した。In addition, the major axis diameter of the particles in the following examples and comparative examples,
The axial ratio (major axis diameter/minor axis diameter) was expressed as an average value of values measured from electron micrographs.
実施例１
毎秒３，４ｃ■の割合でＮ２ガスを流すことによって非
酸化性雰囲気に保持された反応容器中に、１．３２ｍｏ
１／ｊ！のＮａ、ＣＯ１水溶液５８ＯＮ及び１３．５ｍ
ｏｌ／ １２のＮａ、ＯＨ水溶液２０．Ｏｊ！ （Ｎａ
ｘＣＯｓに対し１７．６％に該当する。Example 1 A 1.32 mo.
1/j! Na, CO1 aqueous solution 58ON and 13.5m
ol/12 Na,OH aqueous solution 20. Oj! (Na
This corresponds to 17.6% of xCOs.
）を添加（ＮａＩＣＯｆｆ及びＮａＯＨの総和量は、Ｆ
ｅに対し１．５倍当量に該当する。）シた後、Ｆｅ”・
１．５ｓｏｌ／！を含む硫酸第一鉄水溶液４００１を添
加、混合（Ｆｅ”＋濃度は０．６ｍｏｌ／ ｌ該当する
。）シ、温度４５℃において第一鉄を含む沈澱物を生成
した。) (the total amount of NaICOff and NaOH is F
This corresponds to 1.5 times equivalent to e. ) After that, Fe”・
1.5sol/! A ferrous sulfate aqueous solution 4001 containing ferrous sulfate was added and mixed (Fe"+ concentration corresponds to 0.6 mol/l) to form a precipitate containing ferrous at a temperature of 45°C.
上記第一鉄を含む沈澱物からなる懸濁液中に、引き続き
Ｎ！ガスを毎秒３．４ｃｍの割合で吹き込みながら、温
度４５℃で５０分間保持した後、当該第一鉄を含む沈澱
物からなる懸濁液中に、温度４７゛ｃにおいて毎秒４．
５ＣＪ／秒の空気を５．５時間通気して黄褐色沈澱粒子
を生成させた。尚、空気通気中におけるｐＨは８．５〜
１０．０であった。In the suspension consisting of the ferrous iron-containing precipitate, N! After maintaining the temperature at 45° C. for 50 minutes while blowing gas at a rate of 3.4 cm/sec, 4.0 cm/sec at a temperature of 47° C.
Air was bubbled through at 5 CJ/sec for 5.5 hours to form yellow-brown precipitated particles. In addition, the pH during air ventilation is 8.5 ~
It was 10.0.
黄褐色沈澱粒子は、常法により、ｐ別、水洗、乾燥、粉
砕した。The yellow-brown precipitated particles were separated by p, washed with water, dried, and pulverized by a conventional method.
得られた黄褐色粒子粉末は、Ｘ線回折の結果、ゲータイ
トであり、図１に示す電子顕微鏡写真（ｘ ３００００
）から明らかな通り、平均値で長軸径０゜２９μｍ、軸
比（長軸径／短軸径） １２．０の紡錘形を呈した粒子
からなり、粒度が均斉で樹枝状粒子が混在しないもので
あった。As a result of X-ray diffraction, the obtained yellow-brown particles were found to be goethite, and the electron micrograph shown in Figure 1 (x 30,000
), it consists of spindle-shaped particles with an average major axis diameter of 0°29 μm and an axial ratio (major axis diameter/minor axis diameter) of 12.0, and the particle size is uniform and dendritic particles are not mixed. Met.
実施例２〜５、比較例１〜２
第一鉄を含む沈澱物の生成反応におけるＮ、ガス流量、
炭酸アルカリの種類、濃度及び使用量、水酸化アルカリ
の種類、濃度、使用量、混合割合及び添加時期、アルカ
リ総和量、Ｆｅ”″水溶液の種類、濃度及び使用量、反
応（Ｆｅ”）濃度、混合時温度、熟成工程におけるＮ、
ガス流量、温度及び時間並びに酸化工程における温度及
び空気流量を種々変化させた以外は、実施例１と同様に
して黄褐色粒子粉末を得た。Examples 2 to 5, Comparative Examples 1 to 2 N, gas flow rate in the reaction for producing a precipitate containing ferrous iron,
Type, concentration and usage amount of alkali carbonate, type, concentration, usage amount, mixing ratio and addition time of alkali hydroxide, total amount of alkali, type, concentration and usage amount of Fe"" aqueous solution, reaction (Fe") concentration, Temperature during mixing, N during aging process,
Yellow-brown particles were obtained in the same manner as in Example 1, except that the gas flow rate, temperature and time, and the temperature and air flow rate in the oxidation step were varied.
この時の主要製造条件及び緒特性を表１及び表２に示す
。The main manufacturing conditions and characteristics at this time are shown in Tables 1 and 2.
実施例２〜５で得られた紡錘形を呈したゲータイト粒子
粉末は、いずれも粒度が均斉で樹枝状粒子が混在しない
ものであった０図２は、実施例４で得られた紡錘形を呈
したゲータイト粒子粉末の電子顕微鏡写真（ｘ ３００
００）である。The spindle-shaped goethite particles obtained in Examples 2 to 5 all had uniform particle sizes and did not contain dendritic particles. Figure 2 shows the spindle-shaped goethite particles obtained in Example 4. Electron micrograph of goethite particle powder (x 300
00).
また、比較例１及び比較例２で得られた粒子粉末はそれ
ぞれ図３及び図４に示す電子顕微鏡写真（Ｘ ３０００
０）及びＸ線回折の結果、いずれも紡錘形を呈したゲー
タイト粒子中に粒状を呈したマグネタイト粒子が混在し
ていた。In addition, the particles obtained in Comparative Example 1 and Comparative Example 2 are shown in electron micrographs (X 3000
0) and X-ray diffraction results showed that granular magnetite particles were mixed in spindle-shaped goethite particles.
本発明に係る紡錘形を呈したゲータイト粒子粉末の製造
法によれば、前出実施例に示した通り、高濃度の反応が
可能で、且つ、アルカリ性水溶液の鉄に対する使用割合
を少なくすることが可能であり、しかも塾成工程におけ
るエネルギー量の節減が可能であることに起因して生産
性を高めることができる省資源、省エネルギーの反応に
よって軸比（長軸径／短軸径）が大きな紡錘形を呈した
ゲータイト粒子を工業的、経済的に有利に得ることがで
きる。According to the method for producing goethite particles exhibiting a spindle shape according to the present invention, as shown in the above-mentioned example, it is possible to perform a reaction at a high concentration, and it is also possible to reduce the ratio of the alkaline aqueous solution to iron. Moreover, it is possible to reduce the amount of energy in the cramming process, which increases productivity.It is possible to create a spindle shape with a large axial ratio (major axis diameter / short axis diameter) due to resource and energy saving reactions that can increase productivity. The resulting goethite particles can be obtained industrially and economically advantageously.
図１乃至図４は、いずれも電子顕微鏡写真（×３０００
０ ）である。
図１及び図２は、それぞれ、実施例１及び実施例４で得
られた紡錘形を呈したゲータイト粒子粉末である。
図３及び図４は、それぞれ比較例１及び比較例２で得ら
れた紡錘形を呈したゲータイト粒子粉末と粒状を呈した
マグネタイト粒子粉末との混合粒子粉末である。Figures 1 to 4 are all electron micrographs (×3000
0). 1 and 2 show spindle-shaped goethite particles obtained in Example 1 and Example 4, respectively. 3 and 4 show mixed particle powders of spindle-shaped goethite particles and granular magnetite particles obtained in Comparative Example 1 and Comparative Example 2, respectively.
Claims (1)
られたＦｅＣＯ＿３を含む水溶液を非酸化性雰囲気下に
おいて熟成した後、該ＦｅＣＯ＿３を含む水溶液中に酸
素含有ガスを通気して酸化することにより紡錘形を呈し
たゲータイト粒子粉末を生成させる方法において、前記
炭酸アルカリ、前記ＦｅＣＯ＿３を含む水溶液及び熟成
を行わせている前記ＦｅＣＯ＿３を含む水溶液のいずれ
かの液中に前記炭酸アルカリに対し１〜５０％の水酸化
アルカリを添加することにより、炭酸アルカリ及び水酸
化アルカリの総和量が前記第一鉄塩水溶液中のＦｅ＾２
＾＋に対し１．１〜２．５倍当量とするとともに、前記
熟成における熟成温度を３０〜６０℃且つ熟成時間を１
０〜１００分間とすることを特徴とする紡錘形を呈した
ゲータイト粒子粉末の製造法。(1) After aging an aqueous solution containing FeCO_3 obtained by reacting an alkali carbonate and an aqueous ferrous salt solution in a non-oxidizing atmosphere, oxygen-containing gas is passed through the aqueous solution containing FeCO_3 to oxidize it. In the method of producing spindle-shaped goethite particles, the alkali carbonate, the FeCO_3-containing aqueous solution, and the FeCO_3-containing aqueous solution undergoing aging contain 1 to 1% of the alkali carbonate. By adding 50% alkali hydroxide, the total amount of alkali carbonate and alkali hydroxide is reduced to Fe^2 in the ferrous salt aqueous solution.
The amount is 1.1 to 2.5 times equivalent to
A method for producing goethite particles exhibiting a spindle shape, characterized in that the process is carried out for 0 to 100 minutes.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP63202137A JP2704525B2 (en) | 1988-08-12 | 1988-08-12 | Method for producing spindle-shaped goethite particles |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP63202137A JP2704525B2 (en) | 1988-08-12 | 1988-08-12 | Method for producing spindle-shaped goethite particles |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0251429A true JPH0251429A (en) | 1990-02-21 |
| JP2704525B2 JP2704525B2 (en) | 1998-01-26 |
Family
ID=16452574
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP63202137A Expired - Fee Related JP2704525B2 (en) | 1988-08-12 | 1988-08-12 | Method for producing spindle-shaped goethite particles |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2704525B2 (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5599378A (en) * | 1988-12-22 | 1997-02-04 | Toda Kogyo Corp. | Spindle-shaped magnetic iron based alloy particles and process for producing the same |
| US5650131A (en) * | 1993-11-01 | 1997-07-22 | Minnesota Mining And Manufacturing Company | Process for making goethite |
-
1988
- 1988-08-12 JP JP63202137A patent/JP2704525B2/en not_active Expired - Fee Related
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5599378A (en) * | 1988-12-22 | 1997-02-04 | Toda Kogyo Corp. | Spindle-shaped magnetic iron based alloy particles and process for producing the same |
| US5650131A (en) * | 1993-11-01 | 1997-07-22 | Minnesota Mining And Manufacturing Company | Process for making goethite |
Also Published As
| Publication number | Publication date |
|---|---|
| JP2704525B2 (en) | 1998-01-26 |
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