JP3878007B2

JP3878007B2 - Method for quantifying elements contained in samples with active metals

Info

Publication number: JP3878007B2
Application number: JP2001372209A
Authority: JP
Inventors: 泰成柳; 雅樹立川; 純一待田
Original assignee: Santoku Corp
Current assignee: Santoku Corp
Priority date: 2001-12-06
Filing date: 2001-12-06
Publication date: 2007-02-07
Anticipated expiration: 2021-12-06
Also published as: JP2003172714A

Description

【０００１】
【発明の属する技術分野】
本発明は、希土類金属−鉄−ホウ素系の磁石用合金からなる活性金属を有する試料の含有元素を、蛍光X線法により容易に、優れた精度で分析・定量することができる活性金属を有する試料の含有元素定量方法に関する。
【０００２】
【従来の技術】
未知試料の含有元素を定量する方法としては、蛍光X線分析法が知られている。この蛍光X線分析法により定量する分析用試料の作製法としては、例えば、未知試料を酸溶解し、ろ紙等に染み込ませる点滴法；未知試料を酸溶解し、専用の液体ホルダーに溶液を封入する溶液法；未知試料を直接又は酸溶解後、酸溶解液を濾紙粉末等の吸着体に吸着させ、焼成し酸化物とするか、若しくは水酸化物等の沈殿を作製した後、酸化物とし、次いで、得られた酸化物をホウ酸アルカリの融剤に溶解させ、分析用ガラスビートを作製するガラスビート法；未知試料を直接又は酸溶解後、酸溶解液を濾紙粉末等の吸着体に吸着させ、焼成し酸化物とするか、若しくは水酸化物等の沈殿を作製した後、酸化物とし、次いで、得られた酸化物を微粉砕し、必要に応じてバインダーを加え、加圧成形し、分析用成形体試料を得る酸化物プレス成形法；未知試料が金属又は合金の場合、これを溶解し、鋳型で鋳造後、切断、研磨し分析用試料片を得る合金研磨法、未知試料を粒度5μm以下程度にまで粉砕し、必要に応じてバインダーを加え、加圧成形し、分析用成形試料を得る紛体成形法が行われている。
【０００３】
【発明が解決しようとしている課題】
上記点滴法及び溶液法は、前処理が煩雑であり、しかも蛍光X線強度が十分に得られないため、再現性に乏しいという問題がある。また、前記ガラスビート法及び酸化物プレス成形法は、同じく前処理が煩雑であり、分析に熟練を要すため、分析結果が分析担当者による個人差により大きく変化する可能性があるという問題が生じる。更に、前記合金研磨法は、鋳造時の組成の不均一性により、X線を照射する研磨面の合金組成が全体の組成と異なる場合が多く、再現性が低いという問題がある。
一方、前記紛体成形法は、前処理が非常に容易であるという利点があるが、いわゆる鉱物効果を防ぐために粒度を5μm以下程度にまで微粉砕する必要がある。
ところで、分析試料に発火性を有する活性金属が含まれている場合、上述の5μm以下程度まで微粉砕を行う粉体成形法では発火の危険性が高くなるため、発火防止に雰囲気制御を行う必要があり、多大な設備及び労力を要するという問題が生じる。そこで、特開2001-56273号公報に、活性金属を含む分析試料を、非酸化性の極低温液化ガスにより冷却した後に粉砕を行う分析試料の処理方法が提案されている。しかし、この方法においても、非酸化性の極低温液化ガスを注入する装置や特殊な粉砕装置が必要となる。
また、粉体成形法においては、上述の微粉砕が行われているため、分析試料に例えば、希土類金属等の強度の低い成分が含まれている場合、該強度の低い成分が選択的に微細化される。このため、選択的に微細化された強度の低い成分は、その回収が困難となり、分析に供する回収物の組成が分析試料と異なるものとなるケースが多い。
以上の点から、活性金属を有する未知試料の分析には、上述の前処理が容易な粉体成形法が採用されることは少なく、通常、前処理が煩雑である酸化物プレス成形法等が採用されているのが実状である。
ところで、上述の各方法により作製された分析用試料の蛍光Ｘ線分析の結果は、通常、検量線法又はファンダメンタルパラメーター法(FP法)により含有成分の定量が行われる。前記検量線法は、分析対象の元素であって、組成が既知の標準分析用試料に基づき検量線を作成し、この検量線を利用して定量を行う方法であり、FP法は、予め算出された理論X線強度から算出する方法である。
前記検量線を用いて含有元素の定量を行う場合、従来は、分析用試料と同種の成分含有量が既知の標準分析用試料に基づいて作成した検量線が用いられる。例えば、分析用試料が、前記粉体成形法で作製した合金である場合、標準分析用試料は、同様に粉体成形法で作製した合金が用いられる。そして、得られた合金の標準分析用試料は、検量線を作成するために、酸溶解してICPにより組成が決定されるか、若しくは標準分析用試料を直接又は酸溶解後、酸溶解液を濾紙粉末等の吸着体に吸着させ、焼成し酸化物とするか、若しくは水酸化物等の沈殿を作製した後、酸化物とし、次いで、得られた酸化物を微粉砕し、必要に応じてバインダーを加え、加圧成形した後、蛍光X線分析法により組成が決定される。従って、このような標準分析用試料の作製は非常に煩雑である。
一方、分析用試料を前記酸化物プレス成形法で作製した場合、標準分析用試料は、該分析用試料に含まれる成分元素単体の酸化物をそれぞれ秤量した後、混合・成形して作製された酸化物混合物が用いられる。このため、該標準分析用試料の組成は、成分元素単体の酸化物をそれぞれ秤量した際に既に決定されており、標準分析用試料の組成決定が容易であり、且つ検量線を高精度で作成することができる。
ところで、従来、分析用試料が粉体成形法で作製された場合、検量線作成のための標準分析用試料としては、分析用試料を前記酸化物プレス成形法で作製した場合の前記標準分析用試料が使用されることはなかった。その理由は、分析用試料を前記酸化物プレス成形法で作製した場合の標準分析用試料が、合金である分析用試料と異なり酸化物単体の混合物であって、比較対象物と考えられていなかったためと推測される。
【０００４】
従って、本発明の目的は、希土類金属−鉄−ホウ素系の磁石用合金からなる活性金属を有する試料の含有元素を、容易に、且つ安全に、高精度で分析することができる定量方法を提供することにある。
【０００５】
【課題を解決するための手段】
本発明者らは、上記課題を解決するために鋭意検討した。まず、前処理が容易な従来の粉体成形法の改良を試みた。しかし、分析精度や再現性等を保つために、従来行われている試料の5μm以下への粉砕工程を行った場合には、試料に含有される活性金属の発火等の問題を解決することができなかった。そこで、安全性の確保を第1に考慮し、試料の粉砕工程において、試料を特定平均粒径範囲とすることにより発火の危険性を排除してみた。その結果、試料を粒径5μm以下に粉砕しない場合であっても、特定粒度とすることにより、意外にも従来懸念されていた分析精度や再現性の低下が生じず、発火の防止と共に分析精度や再現性の低下が十分抑制されることを見出し本発明を完成した。
すなわち本発明によれば、希土類金属−鉄−ホウ素系の磁石用合金からなる活性金属を有する試料をD50＝10〜40μmの範囲に粉砕した後、加圧成形して分析用試料を作製し、蛍光X線分析法により分析用試料を測定し、該分析用試料に含まれる元素単体の酸化物をそれぞれ秤量し、混合・成形して作製した組成既知の複数の標準分析用試料に基づいて作成した検量線を用いて定量することを特徴とする活性金属を有する試料の含有元素定量方法が提供される。
【０００６】
【発明の実施の形態】
以下、本発明につき詳細に説明する。
本発明の定量方法は、測定対象とする未知試料として、活性金属を有する試料を用いる。ここで、活性金属とは、大気中で発火性を有する金属であって、例えば、希土類金属、アルカリ金属、アルカリ土類金属や、タングステン、チタン、ジルコニウム等の遷移金属又はこれらの2種以上の混合物等が挙げられる。
このような活性金属を有する試料は、発火性が高く、かつ機械的強度が低い希土類金属を含む、希土類金属−鉄−ホウ素系の磁石用合金である。
【０００７】
本発明の定量方法においては、まず、上記活性金属を有する試料を、D50(平均粒径)＝10〜40μm、好ましくはD50＝10〜25μmの範囲に粉砕する。D50が10μm未満の場合、含有される活性金属が発火する可能性が高くなり、また微細化された活性金属が粉砕機から回収できず、定量精度が低下する恐れがある。一方、D50が40μmを超えると、後工程における成形性が悪くなり、成形後の成形体試料表面の平坦性が低下し、蛍光X線の乱反射が多くなって分析精度及び再現性が低くなる。
また、粉砕された試料の粒径は、発火等を有効に防止するために、D10が5μm以上が好ましい。一方、後工程における成形性に悪影響を与えないように、D90が140μm以下、特に110μm以下が好ましい。
上記各粒径は、市販の粒度測定器により測定できる。
【０００８】
前記試料の粉砕は、例えば、水素化粉砕や、ボールミル粉砕、ディスクミル粉砕、ジェットミル粉砕等の機械的粉砕等で行われる。ここで、水素化粉砕とは、金属に水素を吸収させて脆化させた後、乳鉢、スタンプミル等の手段で粉砕して金属粉を作製する粉砕方法であり、機械的粉砕では困難である試料の粉砕に特に有用である。
前記試料の粉砕において、試料を上述の特定の平均粒径範囲に好適に制御するには、粉砕に時間を要し、粉砕物回収が煩雑であって非効率的なボールミル粉砕や、粉砕能力が高すぎて粒径の制御が難かしいジェットミル粉砕の採用よりも、水素化粉砕及び／又はディスクミル粉砕の採用が好ましい。粉砕においては、前記水素化粉砕と機械的粉砕とを組合わせて行うこともできる。
前記機械的粉砕は、非酸化性の雰囲気で行うのが好ましいが、実際には上述の平均粒径範囲における発火の危険性が低いので、従来、粉体成形法に使用されているような大掛かりな設備による粉砕雰囲気の厳密な制御は必要としない。
また、実際の粉砕工程において試料を上記特定の平均粒径範囲とするには、分析すべき試料の種類や粉砕法の種類に応じて、予備試験等を行って、粉砕時間等の条件を決定しておくことが好ましい。
【０００９】
本発明の定量方法では、次に、前記特定平均粒径の粉砕試料を、加圧成形して分析用試料を作製する。
前記加圧成形は、例えば、所望形状の金型等に粉砕試料を均一に充填して加圧成形する。この際、必要に応じて粉砕試料を、ステアリン酸、スチレン−マレイン酸共重合物等のバインダーと混練してから金型等に均一に充填して加圧成形しても良い。バインダーを用いる際の粉砕試料とバインダーとの配合割合は、後述の蛍光X線分析法に供することができる分析用試料が作製できれば特に限定されないが、通常、容積比で、粉砕試料：バインダーが1:0.01〜1であることが好ましい。
前記加圧は、通常、１軸プレスにより行うことができる。加圧成形する際の形状及び大きさは、後述の蛍光X線分析法に供することができる形状及び大きさであれば特に限定されず、適宜選択することができる。
【００１０】
本発明の定量方法では、次に、加圧成形して得た分析用試料を蛍光X線分析法により分析し、定量することにより行うことができる。蛍光X線分析は、通常の蛍光X線分析装置を用いて条件を適宜選択して行うことができる。分析すべき元素の定量は、検量線法を用いる。
検量線を用いて含有元素の定量を行うには、公知の分析用試料と同じ試料の元素含有量が既知の標準分析用試料に基づいて作成した検量線を用いて行う。分析用試料に含まれる元素単体の酸化物をそれぞれ秤量し、混合・成形して作製した組成既知の複数の標準分析用試料に基づいて作成した検量線を用いて行う。このような方法は、標準分析用試料の作製が従来の粉体成形法によって作製した分析用試料の標準分析用試料の作製より極めて容易であり、しかも、元素単体の酸化物をそれぞれ秤量した際に既に組成が決定されるので、高精度な定量を可能にする検量線を作成することができる。尚、このような標準分析用試料は、合金である分析用試料と異なり酸化物混合物であるため、定量にあたっては、該相違を考慮して検量線から求めた値に補正を行い分析値とする必要がある。
【００１１】
【発明の効果】
本発明の定量方法では、希土類金属−鉄−ホウ素系の磁石用合金からなる活性金属を有する試料を、特定の平均粒径範囲に粉砕する工程を採用するので、また、蛍光 X 線分析法により分析用試料を測定した後の定量を、該分析用試料に含まれる元素単体の酸化物をそれぞれ秤量し、混合・成形して作製した組成既知の複数の標準分析用試料に基づいて作成した検量線を用いて行うので、その含有成分を、容易に、且つ安全に、高精度で分析できる。特に、従来の酸化物プレス成形法で作製した分析試料を用いた場合と同様若しくはそれ以上の高精度で、再現性良く、しかも該方法よりも簡便に定量することができる。また本発明においては、粉砕工程にディスクミル粉砕及び／又は水素化粉砕を採用することにより更に短時間で分析を行うことができる。
【００１２】
【実施例】
以下、本発明を実施例及び比較例により更に詳細に説明するが、本発明はこれらに限定されない。
実施例１
窒素ガスをパージしたディスクミルの粉砕室に、希土類金属−鉄−ホウ素系の磁石用合金である試料(A)を50g投入し、90秒間粉砕後に試料を回収した。回収した粉砕試料のD50(μm)を粒度測定器(日機装社製、マイクロトラックII SRA)により測定した。結果を表１に示す。
次いで、粉砕試料20gを直径32mmのペレット成形用の金型内に均一に充填し、60kNの圧力で1軸プレスし、分析用試料を作製した。得られた分析用試料を蛍光X線分析装置(理学電機社製、SMX-10)により測定し、結果より検量線法を用い、ネオジム、プラセオジムの含有率(質量％)を求めた。結果を表1に示す。
検量線としては、該分析用試料に含まれる元素単体の酸化物をそれぞれ秤量し、混合・成形して作製した組成既知の40個の標準分析用試料に基づいて作成した検量線を用いた。基準値としての酸化物プレス法により作製した分析用試料のネオジム、プラセオジム含有率、該基準値と測定結果との誤差を併せて表1に示す。
【００１３】
実施例２
希土類金属−鉄−ホウ素系の磁石用合金である試料(B)を、雰囲気制御が可能な容器内に配置し、容器内を水素ガス雰囲気とし、試料(B)を脆化させた後、容器内を大気圧にして試料(B)を回収し、乳鉢で粉砕した。得られた粉砕試料を用いて実施例1と同様に分析用試料を作製し、蛍光X線分析を行ってネオジム、プラセオジムの含有率を測定した。また、実施例1と同様に検量線を作成し各測定を行った。結果を表1に示す。
【００１４】
実施例３〜９、参考例１、２
試料として、希土類金属−鉄−ホウ素系の磁石用合金である試料(C)、(E)〜(H)、(J)、(K)、希土類金属−ニッケル系の2次電池用合金である試料(D)、(I)を用い、粉砕時間を、表1に示す時間に変更した以外は実施例1と同様に分析試料を作製し、蛍光X線分析を行って希土類金属−鉄−ホウ素系の磁石用合金についてはネオジム、プラセオジムの含有率を、希土類金属−ニッケル系の2次電池用合金についてはランタン、セリウム、コバルトの含有率を測定した。結果を表１に示す。
【００１５】
比較例１〜７、参考比較例１、２
試料として、実施例1〜7 及び参考例 1 〜 2と同じ試料(A)〜(I)を用い、粉砕時間を、表2に示す時間に変更した以外は、実施例1と同様に分析試料を作製し、蛍光X線分析を行って希土類金属−鉄−ホウ素系の磁石用合金についてはネオジム、プラセオジムの含有率を、希土類金属−ニッケル系の2次電池用合金についてはランタン、セリウム、コバルトの含有率を測定した。結果を表2に示す。
尚、比較例1では粉砕後の試料を回収する際発火した。また比較例2では粉砕後の試料をプレス成形できなかった。
【００１６】
また、実施例1〜9 及び参考例 1 〜 2における各測定結果と基準値との誤差の最大値、最小値、平均値、誤差範囲及び標準偏差、並びに比較例3〜7 及び参考比較例 1 、 2における各測定結果と基準値との誤差の最大値、最小値、平均値、誤差範囲及び標準偏差を表3に示す。
【００１７】
【表１】

【００１８】
【表２】

【００１９】
【表３】

[0001]
BACKGROUND OF THE INVENTION
The present invention has an active metal capable of easily analyzing and quantifying an element contained in a sample having an active metal made of a rare earth metal-iron-boron magnet alloy by a fluorescent X-ray method with excellent accuracy. The present invention relates to a method for quantifying elements contained in a sample.
[0002]
[Prior art]
X-ray fluorescence analysis is known as a method for quantifying the elements contained in an unknown sample. Examples of methods for preparing analytical samples to be quantified by this X-ray fluorescence analysis include, for example, the drip method in which an unknown sample is acid-dissolved and soaked in filter paper; the unknown sample is acid-dissolved and the solution is sealed in a dedicated liquid holder solution method is; directly or after acid dissolution unknown sample, acid solution was adsorbed onto the adsorbent filter paper powder and the like, or a calcined oxide, or after work made the precipitation of hydroxides, oxides Then, the obtained oxide is dissolved in an alkali borate flux to produce a glass beet for analysis; an unknown sample is directly or after acid dissolution, and then the acid solution is adsorbent such as filter paper powder. adsorbed to, or a calcined oxide, or after work made precipitation such as a hydroxide, an oxide, and then the oxide obtained milled, a binder is added if necessary, pressurized Oxide press to obtain a molded sample for analysis by pressure molding Molding method: If the unknown sample is a metal or alloy, melt it, cast it with a mold, cut and polish it to obtain a sample piece for analysis, grinding the unknown sample to a particle size of about 5μm or less Accordingly, a powder molding method is performed in which a binder is added and pressure-molded to obtain a molded sample for analysis.
[0003]
[Problems to be solved by the invention]
The drip method and the solution method have a problem that the pretreatment is complicated and the fluorescent X-ray intensity cannot be sufficiently obtained, so that the reproducibility is poor. In addition, the glass beet method and the oxide press molding method are similarly complicated in pre-processing and require skill in analysis, so that there is a problem that the analysis result may vary greatly depending on individual differences by the person in charge of analysis. Arise. Furthermore, the alloy polishing method has a problem that due to non-uniformity of the composition at the time of casting, the alloy composition of the polished surface irradiated with X-rays is often different from the entire composition, and the reproducibility is low.
On the other hand, the powder forming method has an advantage that the pretreatment is very easy, but it is necessary to finely pulverize the particle size to about 5 μm or less in order to prevent the so-called mineral effect.
By the way, if the analysis sample contains an ignitable active metal, the above-mentioned powder forming method that pulverizes to about 5 μm or less increases the risk of ignition, so it is necessary to control the atmosphere to prevent ignition. There is a problem that a great amount of equipment and labor are required. Japanese Patent Laid-Open No. 2001-56273 proposes a method for processing an analytical sample in which an analytical sample containing an active metal is cooled after being cooled with a non-oxidizing cryogenic liquefied gas. However, this method also requires a device for injecting a non-oxidizing cryogenic liquefied gas and a special grinding device.
In the powder molding method, since the above-described fine pulverization is performed, for example, when the analysis sample contains a low-strength component such as a rare earth metal, the low-strength component is selectively finely divided. It becomes. For this reason, the selectively refined component with low strength is difficult to recover, and the composition of the recovered material used for analysis is often different from the analysis sample.
In view of the above, the analysis of unknown samples having active metals is rarely performed by the above-described powder forming method that allows easy pretreatment, and usually includes oxide press forming methods that require complicated pretreatment. The actual situation is adopted.
By the way, as for the result of the fluorescent X-ray analysis of the analytical sample produced by each of the above-described methods, the contained components are usually quantified by the calibration curve method or the fundamental parameter method (FP method). The calibration curve method is a method of preparing a calibration curve based on a standard analysis sample having an element to be analyzed and having a known composition, and performing quantification using this calibration curve. The FP method is calculated in advance. It is a method of calculating from the calculated theoretical X-ray intensity.
When quantifying the contained elements using the calibration curve, conventionally, a calibration curve created based on a standard analysis sample whose component content is the same as that of the analysis sample is used. For example, when the analytical sample is an alloy produced by the powder molding method, an alloy produced by the powder molding method is used as the standard analytical sample. In order to prepare a calibration curve, the standard analysis sample of the obtained alloy is acid-dissolved and the composition is determined by ICP, or the standard analysis sample is directly or after acid dissolution, adsorbed on the adsorbent filter paper powder and the like, or a calcined oxide, or after work made precipitation such as a hydroxide, an oxide, then finely pulverized oxide obtained, optionally After adding a binder and press-molding, the composition is determined by X-ray fluorescence analysis. Therefore, preparation of such a sample for standard analysis is very complicated.
On the other hand, when the analytical sample was prepared by the oxide press molding method, the standard analytical sample was prepared by weighing each component element oxide contained in the analytical sample, followed by mixing and molding. An oxide mixture is used. Therefore, the composition of the standard analysis sample is already determined when each component element oxide is weighed, the composition of the standard analysis sample is easy to determine, and a calibration curve is created with high accuracy. can do.
By the way, conventionally, when an analytical sample is produced by a powder molding method, the standard analytical sample for preparing a calibration curve is the standard analytical sample when the analytical sample is produced by the oxide press molding method. Samples were never used. The reason for this is that the standard analytical sample when the analytical sample is produced by the oxide press molding method is a mixture of simple oxides unlike the analytical sample that is an alloy, and is not considered a comparison object. It is estimated that
[0004]
Accordingly, an object of the present invention is to provide a quantitative method capable of easily, safely and accurately analyzing elements contained in a sample having an active metal made of a rare earth metal-iron-boron magnet alloy. There is to do.
[0005]
[Means for Solving the Problems]
The present inventors diligently studied to solve the above problems. First, an attempt was made to improve the conventional powder molding method that facilitates pretreatment. However, in order to maintain analysis accuracy, reproducibility, etc., when the conventional pulverization process to 5 μm or less of the sample is performed, problems such as ignition of active metal contained in the sample may be solved. could not. Therefore, considering safety first, we tried to eliminate the risk of ignition by setting the sample to a specific average particle size range in the sample crushing process. As a result, even if the sample is not pulverized to a particle size of 5 μm or less, the analysis accuracy and reproducibility, which had been a concern in the past, are not reduced by using a specific particle size. And the present invention has been completed.
That is, according to the present invention, a sample having an active metal composed of a rare earth metal-iron-boron magnet alloy is pulverized into a range of D50 = 10-40 μm, and then pressure-molded to prepare an analytical sample. Prepared based on multiple standard analytical samples with known compositions prepared by measuring an analytical sample by fluorescent X-ray analysis, weighing each elemental oxide contained in the analytical sample, mixing and molding There is provided a method for quantifying contained elements in a sample having an active metal, characterized in that quantification is performed using a calibration curve .
[0006]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail.
In the quantification method of the present invention, a sample having an active metal is used as an unknown sample to be measured. Here, the active metal is a metal having an ignitability in the atmosphere, for example, a rare earth metal, an alkali metal, an alkaline earth metal, a transition metal such as tungsten, titanium, zirconium, or two or more of these metals A mixture etc. are mentioned.
Samples having such active metal, high catch fire resistance, and mechanical strength is low rare earth metals including rare earth metals - iron - is alloy for boron magnet.
[0007]
In the quantification method of the present invention, first, the sample having the active metal is pulverized in a range of D50 (average particle diameter) = 10 to 40 μm, preferably D50 = 10 to 25 μm. When D50 is less than 10 μm, there is a high possibility that the contained active metal is ignited, and the refined active metal cannot be recovered from the pulverizer, and the quantitative accuracy may be lowered. On the other hand, if D50 exceeds 40 μm, the moldability in the subsequent process is deteriorated, the flatness of the surface of the molded article sample after molding is lowered, the diffuse reflection of fluorescent X-rays is increased, and the analysis accuracy and reproducibility are lowered.
Further, the particle size of the crushed sample is preferably D10 of 5 μm or more in order to effectively prevent ignition and the like. On the other hand, D90 is preferably 140 μm or less, particularly preferably 110 μm or less so as not to adversely affect the formability in the subsequent process.
Each said particle size can be measured with a commercially available particle size measuring device.
[0008]
The sample is pulverized by, for example, hydrogen pulverization, mechanical pulverization such as ball mill pulverization, disk mill pulverization, jet mill pulverization, or the like. Here, the hydrogenation crushing, after embrittlement by hydrogen absorption in metal, mortar, a pulverization method was triturated with means such as a stamp mill to steel work metal powder, difficult with mechanical pulverization It is particularly useful for grinding certain samples.
In the pulverization of the sample, in order to suitably control the sample to the above-mentioned specific average particle size range, it takes time for the pulverization, the pulverized material recovery is complicated, and inefficient ball mill pulverization and pulverization ability are required. Adopting hydrogenation and / or disk milling is preferable to adopting jet milling which is too high to control the particle size. In the pulverization, the hydrogenation pulverization and the mechanical pulverization may be performed in combination.
The mechanical pulverization is preferably performed in a non-oxidizing atmosphere, but in practice, since there is a low risk of ignition in the above average particle size range, it is a large-scale one that is conventionally used in powder molding methods. Strict control of the pulverizing atmosphere with a simple facility is not required.
In addition, in order to bring the sample into the specific average particle size range in the actual pulverization process, a preliminary test is conducted according to the type of sample to be analyzed and the type of pulverization method, and conditions such as pulverization time are determined. It is preferable to keep it.
[0009]
In the quantification method of the present invention, the pulverized sample having the specific average particle diameter is then pressure-molded to prepare an analytical sample.
The pressure molding is performed by, for example, uniformly filling a pulverized sample in a mold having a desired shape and the like. At this time, if necessary, the pulverized sample may be kneaded with a binder such as stearic acid or a styrene-maleic acid copolymer, and then uniformly filled into a mold or the like, followed by pressure molding. The blending ratio of the pulverized sample and the binder when using the binder is not particularly limited as long as an analytical sample that can be used in the fluorescent X-ray analysis method described below can be prepared. Usually, the pulverized sample: binder is 1 in volume ratio. : It is preferable that it is 0.01-1.
The pressurization can usually be performed by a uniaxial press. The shape and size at the time of pressure molding are not particularly limited as long as the shape and size can be used for the fluorescent X-ray analysis described later, and can be appropriately selected.
[0010]
In the quantification method of the present invention, the analysis sample obtained by pressure molding can then be analyzed by fluorescent X-ray analysis and quantified. The fluorescent X-ray analysis can be performed by appropriately selecting conditions using a normal fluorescent X-ray analyzer. The calibration curve method is used for quantification of the element to be analyzed .
Quantitative rows urchin elements contained by using a calibration curve is carried out using a calibration curve prepared on the basis of element content of the same sample with a known sample for analysis in the known standard analytical sample. Each of the elemental oxides contained in the analysis sample is weighed, mixed, and molded, and the measurement is performed using a calibration curve prepared based on a plurality of standard analysis samples with known compositions . In such a method, the preparation of the standard analysis sample is much easier than the preparation of the standard analysis sample of the analysis sample prepared by the conventional powder molding method, and furthermore, when each elemental oxide is weighed. Since the composition has already been determined, a calibration curve that enables highly accurate quantification can be created. In addition, since such a standard analysis sample is an oxide mixture unlike an analysis sample that is an alloy, in quantification, the value obtained from the calibration curve is corrected to the analysis value in consideration of the difference. There is a need.
[0011]
【The invention's effect】
The quantification method of the present invention, a rare earth metal - iron - a sample having a boron-based active metal made of an alloy for a magnet, since adopting a step of milling the specific average particle size range, and by X-ray fluorescence analysis Calibration after measurement of the analytical sample was prepared based on a plurality of standard analytical samples with known compositions prepared by weighing each elemental oxide contained in the analytical sample, mixing and molding Since the process is performed using a line, the contained components can be analyzed easily and safely with high accuracy. In particular, it is possible to perform quantitative determination more easily than the method with high reproducibility with high accuracy similar to or higher than that in the case of using an analytical sample prepared by a conventional oxide press molding method. In the present invention, analysis can be performed in a shorter time by employing disk milling and / or hydrogenation grinding in the grinding step .
[0012]
【Example】
Hereinafter, although an example and a comparative example explain the present invention still in detail, the present invention is not limited to these.
Example 1
50 g of the sample (A), which is a rare earth metal-iron-boron magnet alloy, was charged into the pulverization chamber of the disk mill purged with nitrogen gas, and the sample was recovered after pulverization for 90 seconds. D50 (μm) of the collected pulverized sample was measured with a particle size measuring device (manufactured by Nikkiso Co., Ltd., Microtrac II SRA). The results are shown in Table 1.
Next, 20 g of the pulverized sample was uniformly filled into a mold for forming a pellet having a diameter of 32 mm, and uniaxially pressed at a pressure of 60 kN to prepare a sample for analysis. The obtained sample for analysis was measured with a fluorescent X-ray analyzer (manufactured by Rigaku Corporation, SMX-10), and the content rate (mass%) of neodymium and praseodymium was determined from the results using a calibration curve method. The results are shown in Table 1.
The calibration curve, use a calibration curve prepared on the basis of oxides of elemental alone that are included in the sample for the analysis were weighed, of known composition prepared mixed and molded to the 40 standard analytical sample It was. Table 1 shows the neodymium and praseodymium content of the sample prepared by the oxide press method as the reference value, and the error between the reference value and the measurement result.
[0013]
Example 2
The sample (B), which is a rare earth metal-iron-boron magnet alloy, is placed in a container capable of controlling the atmosphere, the inside of the container is made a hydrogen gas atmosphere, and the sample (B) is embrittled. The inside (atmospheric pressure) was collected and the sample (B) was collected and ground in a mortar. Using the obtained ground sample, an analytical sample was prepared in the same manner as in Example 1, and the content of neodymium and praseodymium was measured by fluorescent X-ray analysis. In addition, a calibration curve was prepared in the same manner as in Example 1, and each measurement was performed. The results are shown in Table 1.
[0014]
Examples 3 to 9, Reference Examples 1 and 2
Samples (C), (E) to (H), (J), (K), which are rare earth metal-iron-boron magnet alloys, are rare earth metal-nickel secondary battery alloys. Samples (D) and (I) were used, and an analysis sample was prepared in the same manner as in Example 1 except that the pulverization time was changed to the time shown in Table 1, and X-ray fluorescence analysis was performed to obtain a rare earth metal-iron-boron. The content ratios of neodymium and praseodymium were measured for the alloys for magnets, and the content ratios of lanthanum, cerium, and cobalt were measured for the rare earth metal-nickel secondary battery alloys. The results are shown in Table 1.
[0015]
Comparative Examples 1-7, Reference Comparative Examples 1, 2
As samples, the same samples (A) to (I) as in Examples 1 to 7 and Reference Examples 1 to 2 were used, and the pulverization time was changed to the time shown in Table 2, and the analysis sample was the same as in Example 1. The rare earth metal-iron-boron magnet alloy is neodymium and praseodymium content, and the rare earth metal-nickel secondary battery alloy is lanthanum, cerium, cobalt. The content of was measured. The results are shown in Table 2.
In Comparative Example 1, ignition occurred when collecting the crushed sample. In Comparative Example 2, the pulverized sample could not be press molded.
[0016]
Further, the maximum value, minimum value, average value, error range and standard deviation of the error between each measurement result and the reference value in Examples 1 to 9 and Reference Examples 1 to 2 , and Comparative Examples 3 to 7 and Reference Comparative Example 1 indicates the maximum value of the error between the measurement result and the reference value at 2, minimum, average, the error range and standard deviation Table 3.
[0017]
[Table 1]

[0018]
[Table 2]

[0019]
[Table 3]

Claims

After pulverizing a sample with an active metal composed of a rare earth metal-iron-boron magnet alloy to the range of D50 = 10-40μm, press-molding to prepare a sample for analysis, and analyzing by X-ray fluorescence analysis Measure using a calibration curve created based on multiple standard analytical samples of known composition prepared by measuring each sample element, weighing each elemental oxide contained in the analytical sample, mixing and molding A method for quantifying an element contained in a sample having an active metal.

The grinding of samples having an active metal, quantitative method of claim 1, wherein the performing by disc milling and / or hydrogenated grinding.