Yoshizo Miyake

EMISSION-SPECTROMETRIC DETERMINATION OF TRACE RARE-EARTH ELEMENTS IN YTTRIUM OXIDE USING CsCl-GRAPHITE BUFFER.

ZusammenfassungDurch den Zusatz des CsCl-Graphitpuffers werden Verdampfungsgeschwindigkeit und Emissionsintensität erhöht, die Temperatur im Bogenplasma herabgesetzt und eine gleichmäßige Verteilung der Atome und Ionen längs der Entladungsstrecke bewirkt. Empfindlichkeit und Genauigkeit der Bestimmung sind besser als bei Verwendung anderer Puffer. 10 Verunreinigungselemente können mit Nachweisgrenzen von 1–20 ppm in hochreinem Yttriumoxid bestimmt werden. Die Variationskoeffizienten liegen unter 20%.SummaryAn emission-spectrometric method was applied in the presence of CsCl-graphite buffer for the quantitative determination of traces of rare earth elements in yttrium oxide. The buffer causes an increase of the evaporation rate of the sample and of the emission intensity. The temperature in the arc plasma is decreased, and the atoms and ions of rare earths distribute uniformly along the axis of the discharge gap. The CsCl-graphite buffer enhances the sensitivity and the precision of the analytical elements to a larger extent than other buffers and permits the determination of microquantities of 10 impurity elements within limits of detection from 1 to 20 ppm in high-purity yttrium oxide. The coefficients of variation are less than 20%.

Emission-spectrometric determination of trace non-rare earth elements in yttrium oxide using AgF-Ga2O3 mixed carrier

ZusammenfassungDas Trägergemisch bewirkt eine Erhöhung der Verdampfungsgeschwindigkeit der zu bestimmenden Elemente und der Anzahl der Atome im Bogenplasma. Es verbessert mehr als andere Träger die Empfindlichkeit und ermöglicht die Bestimmung von Mikromengen der Elemente (Mg, Ca, Mn, Co, Fe, Pb, Cu, Cd, Al, B, Sn, As, Bi) in hochreinem Yttriumoxid mit Nachweisgrenzen von 0,1–13 ppm. Die Variationskoeffizienten liegen unter 20%.SummaryAn emission-spectrometric method is described for the quantitative determination of traces of non-rare earth elements in yttrium oxide, employing addition of AgF-Ga2O3 mixed carrier. This addition effects an increase of the rate of evaporation of the analytical elements and of the number of atoms in the arc plasma. It enhances the sensitivity of the analytical elements to a larger extent than other carriers and permits the determination of microquantities of the elements (Mg, Ca, Mn, Co, Fe, Pb, Cu, Cd, Al, B, Sn, As, Bi) within limits of detection from 0.1 to 13 ppm in high-purity yttrium oxide. The coefficients of variation are less than 20%.

Effect of CsCl-graphite buffer on the properties of a d.c. arc in the emission-spectrometric analysis of neodymium oxide

ZusammenfassungDie Wirkung des Puffers wurde durch Messung der Linienintensität, der Bogentemperatur, der Elektronendichte, der Atomkonzentration und der Verweilzeit der Teilchen im Bogenplasma untersucht. Durch den Puffer wird eine konstante Verdampfungsgeschwindigkeit der Seltenen Erden, eine größere Flüchtigkeit der Probe, eine Erhöhung der Anzahl der Atome im Bogenplasma und eine gleichmäßige Verteilung der Atome und Ionen der Seltenen Erden längs der Bogenachse erzielt. Diese Wirkungen werden durch die Abnahme des Ionisierungsgrades der Seltenen Erden mit steigender Elektronendichte und der Zunahme der Verweilzeit der Atome und Ionen im Bogenplasma erklärt. Der Puffer verbessert die Empfindlichkeit und Reproduzierbarkeit und gestattet die Bestimmung von Mikromengen Seltener Erden in Neodymoxid mit Nachweisgrenzen von 2–9 ppm. Die Variationskoeffizienten liegen unter 14%.SummaryThe effects of CsCl-graphite buffer on the properties of a d.c. arc in the emission-spectrometric determination of traces of rare earth elements in neodymium oxide were investigated by measuring the line intensity, arc temperature, electron density, atomic concentration and residence time of rare earth particles in the arc plasma. The buffer gives a constant rate of evaporation of rare earth elements, as well as greater volatility of the sample and causes the increase of the number of atoms in the arc plasma. The atoms and ions of rare earths distribute uniformly along the axis of the discharge gap. This enhancing effects are interpreted by the decrease of the ionization degree of rare earths with increasing electron density, and by the increase of the residence time of the atoms and ions of rare earths in the arc plasma. The buffer enhances the sensitivity and reproducibility and permits the determination of microquantities of rare earth elements with limits of detection from 2 to 9 ppm in neodymium oxide. The coefficients of variation are less than 14%.

EMISSION-SPECTROMETRIC DETERMINATION OF TRACE RARE EARTH ELEMENTS IN EUROPIUM OXIDE.

ZusammenfassungDie Anregung erfolgt im Gleichstrombogen in kontrollierter AtmosphÄre (Argon/Sauerstoff, 4∶1) in Gegenwart eines CsCl-Graphit (1∶9)-Puffers. Durch die Verwendung von Argon/Sauerstoff konnte die IntensitÄt des Untergrundes und der Cyanbanden erheblich reduziert und eine grö\ere Empfindlichkeit erreicht werden als bei der Anregung in Luft. Durch den Puffer wird die Verdampfungsgeschwindigkeit erhöht, die Anzahl der Atome im Bogenplasma vergrö\ert und eine gleichmÄ\ige Verteilung der Atome und Ionen lÄngs der Bogenachse erzielt. Empfindlichkeit und Reproduzierbarkeit werden verbessert. Spurenverunreinigungen von 10 Elementen können in hochreinem Europiumoxid bestimmt werden. Die Nachweisgrenzen liegen zwischen 3 und 11 ppm; der Variationskoeffizient ist < 13%.SummaryA dc arc excitation method in a controlled atmosphere was applied in the presence of CsCl-graphite (1∶9) buffer for the quantitative determination of traces of rare earth elements in europium oxide. The intensities of the cyanogen band spectra and the background could be reduced by the use of argon-oxygen (4∶1) mixed gas atmosphere and it was possible to obtain higher sensitivity than in the excitation in air. Addition of CsCl-graphite buffer causes an increase of the evaporation rate of the sample and of the number of atoms in the arc plasma, and the atoms and ions of rare earths distribute uniformly along the axis of the discharge gap. The buffer enhances the sensitivity and reproducibility and permits the determination of microquantities of 10 impurity elements within limits of detection from 3 to 11 ppm in high-purity europium oxide. The coefficients of variation are less than 13%.

Effect of alkali elements on the axial distribution of line intensity in plasma of high voltage spark

ZusammenfassungEine Zugabe von Caesium beeinflußte die axiale Verteilung der Intensitäten der Atom- und Zonenlinien in der Entladungszone und bewirkte eine Intensitätszunahme im Zentrum. Diese Erscheinungen werden mit dem Pinck-Effekt und einer Veränderung des Ionisierungsgrades erklärt. Die Nachweisgrenzen für Seltene Erden und andere Elemente in Oxiden der Seltenen Erden werden durch Caesiumzusatz verbessert. 1–25 ppm dieser Elemente konnten in Neodym- und Europiumoxid bestimmt werden. Die Variationskoeffizienten liegen unter 13%.SummaryThe effects of alkali elements on the axial distribution of the line intensity in plasma of high voltage spark were investigated, and the role of caesium to achieve optimum sensitivity and good precision in the spark excitation-spectrometric analysis-of rare earth oxides incorporating a rotating electrode was explained. Addition of caesium to the discharge column affected the axial distribution of the intensity of the atomic and ionic lines in the discharge gap and caused an increase of the line intensity in the central region of the discharge gap. These phenomena are interpreted by the ionization pinch effect and variation in the ionization degree. The limits of detection for rare earths and diverse other elements in rare earth oxides were improved by the addition of caesium into the sample solution. Thus, microquantities of the elements within limits of detection from 1 to 25 ppm in neodymium oxide and europium oxide can be determined. The coefficients of variation are less than 13%.

Observations on the effect of organic solvents in the direct-reading emission-spectrometric determination of trace elements in rare-earth compounds by rotating electrode

ZusammenfassungDurch Zusatz von Alkoholen mit niedrigeren Siedepunkten als Wasser wird die Verdampfungsgeschwindigkeit der Lösung erhöht und die Linienintensität gesteigert. Methanol zeigt diese Wirkung in größerem Maße als andere Alkohole und ermöglicht die Bestimmung von Spuren Seltener Erden und anderer Elemente in Selten-Erd-Verbindungen hoher Reinheit mit Nachweisgrenzen von 1–37 ppm. Bei Gegenwart von mehr als 60% Methanol wird das Intensitätsverhältnis der Ionen- zur Atomlinie vergrößert, was auf eine Erhöhung der Plasmatemperatur zurückgeführt wird.SummaryA direct-reading emission-spectrometric method was applied in the presence of methanol for the quantitative determination of traces of rare earths and diverse other elements in rare-earth compounds by the rotating electrode. Addition of alcohols with lower boiling points than water causes an increase of the rate of vaporization of the sample solution and of the emission intensity. Methanol enhances the emission intensity to a larger extent than other alcohols and permits the determination of microquantities of the elements within limits of detection from 1 to 37 ppm in high-purity rare-earth compounds. The intensity ratio of the ionic line to the atomic line increases in the presence of more than 60% methanol, indicating the elevation of plasma temperature.

The Reaction of Europium Oxide with Carbon Disulfide and Thermal Decomposition Processes of the Products

The synthesis of europium sulfide by the reaction of europium oxide with carbon disulfide was investigated, and oR these products the decomposition processeses on heating under some atmesphere were studied.The oxygen content was determined by fast neutron activation method, and the valence stqte of europium ion was estimated by the measurement of paramagnetic susceptibility at room temperature.By heating europium oxide in carbon disulfide vapor, Eu3S4 containing small excess sulfur was formed at 500. v600 C and EuS was formed at 900NIOOOeC. But, the contamination of small amount of carbon was observed in this case. The oxygen contepts in these Eu3S4 and EuS were O.9Nl.1 and O.2. vO.3, respectively.Europium monosulfide was also obtained by thermal decomposition or reduction of Eu3S4 in the stream of nitrogen or hydrogen. The oxygen content in the resultant europium monosulfide was also O.2, wO.3.Europium sulfide was very sensitive to oxidation. Therefore, under the atmosphere of oxygen europium monosulfide was oxidized to Eu202S and Eu, S4 at temperature above 200UC. By further oxidation, small amount of sulfur was removed at 650, v670 C, and the mixture of Eu202SO4and Eu2(SOs)s was formed at 750N8000C.

Removal of Trace Amounts of Arsenic in Sulfur with Adsorbents

For the preduction of extremely pure sulfur by means of distillation, volatile impurities such as arsenic should previously be removed.Several adsorption methods have been tested for the removal of trace amounts of arsenic in sulfur.Carbon, alumina, clay, a11 activated, molecular sieve and silica gel were used as adsorbent in the following methods; 1) treatment of sulfur dissolved in carbon disulfide with various adsorbents, 2) treatment of molten sulfur with various adsorbents, 3) distillation bf sulfur after treatment with various adsorbents, and 4) passing sulfur vapor through heated bed filled with various adsorbents.Excellent results for the removal of arsenic were always obtained in these methods. The third method was the most effective, because arsenic can mostly and easily be removed.The precedure of this treatment was as follows: the sulfur centaining 43 ppm of arsenic was taken into a distilling flask with 10 wt% of activated carbon or activated alumina. The flask was heated at 300, -v5000C and then sulfur was distilled in an inert gas under reduced or ordinary pressure.The content of arsenic decreased te 1-, v2 ppm, which corresponded to 95, -v98600 removal.Next, as a tracer 7aAs was added to sulfur containing l ppm of arsenic previously. The sulfur was distilled according to the above method and the amount of As in distilled sulfur was measured. The content of arsenic was reduced to O. OO1 ppm.

Purification Methods for Phosphorus

電子工業用材料としての要求に応じ得る高純度リンを製造する目的で,微量不純物の除去について検討を行なってきたが,本報ではさらに鉄・鉛・銅・マグネシウム・カルシウム・アルミニウム・カドミウム・ホウ素・ビスマス・スズなど10元素の除去を,酸アルカリ処理・吸着剤処理・合金減圧蒸留・水蒸気蒸留などの方法について検討を行なった。その結果鉄・鉛・カドミウムの除去に対しては硝酸処理または水蒸気蒸留が,ホウ素に対しては硝酸で処理する方法がもっとも効果的であることを認めた。また銅・マグネシウム・カルシウム・アルミニウム・ビスマス・スズに対してはアルカリ処理以外のすべての方法に除去効果のあることが認められた。ここに得られた結果と前報までに得られた結果をもとにして各種精製方法の精製効果を比較検討し,これら精製法を適当に組合わせることにより高純度リンを製造するための一貫した精製法を確立した。

Spectrochemical determination of trace amounts of rare earth elements by vacuum cup electrode

バキュームカップ電極による溶液試料中の微量希土類元素を同時定量する諸条件について検討した.本法による検出限界は交流アーク(ACA)放電では3～17ppm,高圧スパーク(HVS)放電では3～35ppmであり,変動係数は5～17%である.アルゴン中のACA放電では検出感度は著しく向上するが,空気中放電より再現性がわるくなる.HVS放電の場合,他元素の添加によって回転電極にみられるようなスペクトル線強度を高める効果は少ない.ランタンおよびプラセオジムが共存した場合,スペクトル線強度は強められるので濃度を正しく規制しなければならない.精度を必要とする分析にはHVS放電が,感度を必要とする分析にはACA放電がよい.