李 光燮

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博士学位論文の要旨及び審査結果の要旨 (Summary of Thesis(DR))othe

李, 光燮

Tohoku University Repository (TOUR) / 東北大学機関リポジトリ

Purification of La by ExtractionChromatography (抽出クロマトグラフィーによるランタンの高純度化)著者 李 光燮号 53学位授与番号 4153URL http://hdl.handle.net/10097/42567リ クァン ソプ氏 名 李 光 燮授 与 学 位 博士(工学)学 位 授 与 年 月 日 平成21年3月25日学位授与の根拠法規 学位規則第4条 第1項研究科,専攻の名称 東北大学大学院工学研究科(博士課程)知能デバイス材料学専攻学 位 論 文 題 目PurificationofLabyExtractionChromatography(抽出クロマ トグラフィーによるランタンの高純度化)指 導 教 員 東北大学教授 一色 実論 文 審 査 委 員 主査 東北大学教授 一色 実 東北大学教授 佐藤 譲東北大学教授 鈴木 茂論 文 内 容 要 旨   High  purity  La203  is required for application oftarget  material The main purpose of the research isto prepare the high  puritY La203. To obtain the high purity La203, extraction chromatography using D2EHPA impregnated resin is usedas the main purification method to obtain the high purity La203. Also, a strong base  polystyrene-divinylbenzene  quaternary amine type of anion exchange r sin  (DIAION SA  10A) was applied for the  separation f the impurities which cannot be removed by extraction chromatography using D2EHPA impregnated  r sin. Experiments were carried out at room  temperature and in HC1 media Prepared La203 from purified  LaC13 solution by calcinating La oxalate precipitated is evaluated by GDMS. The contents are summarized as follows.   Chapter 1 describedneeds of high purity La203 as  high-ic dielectric material and the purification method of rare earth elements such as ion exchange, solvent extraction, and extraction chromatography. Also, a practical research objective and originality are defined from the issues pointed  out.   Chapter 2 examines the relationship between extraction chromatography  and solvent extraction via batch  experiment.  Also, performance of solvent impregnated resin using D2EHPA, PC88A, Cyanex 923 as solvents i  investigated by batch experiment as functions of ratios between resin and metal solution and  HCl concentration to find the optimum solvent impregnated r sin. As a result, Cyanex 923, PC88A impregnated r sin is not suitable for the separation f Ce, Pr, Nd, and Sm from La, because of the low adsorption ability for the tested elements. However,  D2EHPA impregnated resin has the high adsorption ability and the large separation factors of the examined lements over La. Therefore, D2EHPA impregnated r sin is  found to be the most  appropriate resin among the tested solvent impregnated r sins.— 670  —  In addition, relation between the logarithms of the  distribution coefficients of the examined elements on D2EHPA  impregnated r sin and the equilibrated pH was estimated and represented by a straight line of slope three. This indicates that the mechanisms of olvent extraction a d sorption by solvent impregnated r sin are identical.    In chapter 3, from the results of chapter 2,D2EHPA impregnated resin was used for separation f impurities from La  The batch experiments were carried out in order to obtain the distribution coefficients of La and its major impurities on  D2EHPA impregnated resin and the separation factors were also estimated from the results ofthe distribution  coefficients. A  a result, he separation  factors of the divalent or  trivalent elements were smaller or  larger than unity, respectively. In addition, adsorption  behaviors of the examined elements on D2EHPA impregnated resin were well explained by the extraction mechanism of solvent extraction using D2EHPA.    Based on the results of the distribution coefficients and the separation factors, the extraction  chromatography for La purification was  canied out using  D2EHPA impregnated r sin as stationary phase. The flow rate and the height of the resin bed were varied in this experiment. It is found that he slower flow rate and the higher bed height were desirable. The slowest flow rate and the highest bed height tested in this work were  1  ml  min  rand 180 mm, respectively, for the resin bed with  25  mm diameter, and it was confirmed that his condition was uitable for practical use in the low La  concentration.   Moreover, based on the optimum condition i the low La condition, the separation f impurities from La is  carried out by extraction  chromatography using the D2EHPA impregnated resin and anion exchange by  DIAION  SA-10 in the high La concentration and  HCl media Although there is a problem of decreasing equilibrated  pH,height of bed resin and volume of loading solution is controlled tosolve the problem. Also, column experiment is carried out by changing ofLa concentration t  find a best condition for separation f impurities from La The optimum condition of  360  mm height of resin bed and high La concentration is obtained. Furthermore, the column experiment of semi-pilot column with diameter  50  mm and 720 mm height of resin bed is  carried out in La 15  •m-3. However, there is a problem of the Bi removal from La, because Bi has the same elution  curve with La   Anion exchange r sin of  SA-10 is used for removal of Bi. The condition of Bi removal is 1  mol•drri3  HCl La chloride  solution,  1  ml  min  rflow rate in the small column. Consequently, it was  confirmed that the separation ofLa and other  impurities was possible by a method of extraction chromatography using D2EHPA impregnated resin and anion exchange  using  SA-10.   Chapter 4 describes the  preparation f high purity La203 from purified  LaC13 solution prepared in chapter 3 by oxalate Precipitation method. Also, purity of the specimens and the overall process efficiencies are compared and interpreted.  Firthennore, purity of prepared La203 is evaluated by glow discharge mass  pectrometry (GDMS). According to the oxalate Precipitation method, the optimum condition of La203 preparation is obtained as 50 ml of oxalate solution (0.65 mol), and heating at1083 K for 2 h under 02 atmosphere. Metallic impurities from prepared La203 were evaluated by GDMS. Table I—  671  --displays the impurity concentration detected by GDMS. The first (A) sample shows the data of La203 obtained  itectly by oxalate precipitation f the starting material  (LaC13 solution without treatment of  D2EHPA impregnated resin and anion exchange separation). The second (B) sample shows the data of the La203 obtained by oxalate precipitation from  Laci3 solution purified only by the  D2EHPA impregnated resin. The third (C) sample shows the data of the La203 obtained by oxalate precipitation from  LaC13 solution purified by anion exchange and then D2EHPA impregnated resin. The froth  (3) sample gives the data of commercial 5N  La203.               Table  1The GDMSanalysis of La203.Elements (A) (B) (C)  (D)Rare earth elements / mass nnmSc  Y Ce Pr Nd Sm Eu Gd  Dy Yb 0.012 0.640 8.40 3.70 3.70 5.70 3.20 3.10 0.022 0.850<0.01 <0.01 0.370  1.56 0.085 0.120 0.440 0.087 0.018 0.016 <0.01 <0.01 0.490 0.340 0.096 <0.01 0.039 <0.01 <0.01 <0.01 <0.01 0.110 0.100 4.17  1.52 0.370  1.42 0.400 0.850 0.270 La203/IREO  (%) 99.9953 99.9996 99.9998 99.9989 Non-rare earth elements  / mass  ranMg Al  K Ca Cr  Mn Fe Cu Zn Ga Se Sn Hf Ta Pt Bi1.53 10.26 6.23 9.52 3.18 2.56 3.11 0.450  0.510  1.13 0.790 4.03 0.020 9.51 0.010 0.450 0.4001.89 7.27 4.55 2.23 2.86 2.06 2.74 3.43 0.580 0.200 2.11 0.290 0.390  1.76 0.360 0.350 0.340 1.43 2.61 4.40  1.77 0.400 0.049 3.42 0.220 0.110 0.063 0.160  0.510 0.010 0.900 <0.01 <0.01 <0.01 1.69 4.68 6.21  5.73  1.04  1.31 4.65 2.88 2.76 0.054 4.26 3.31 <0.01 10.61 0.026 0.440 <0.01 Purity (%) 99.967 99.994 99.996 99.992      A: La203 prepared by raw material  LaC13.7H20  (99.1%), B: La203 prepared by treatment extraction chromatography      C: La203  prepared by treatment of anion exchange and extraction chromatography, D: Commercial5N  La203   The purity of produced La203 increased from 99.967% (A) to 99.994% (B) according tothe  D2EHPA impregnated r sin separation. Also, it is  confirmed that he purity of  La203/TREO  (Total Rare  Earth Oxide) remarkably increased from 99.9953 (A) to 99.9996 (B) as the D2EHPA impregnated  r sin separation is  adopted. All rare earth elements could be reduced to less than 1 mass ppm except Pr  (1.56 mass ppm), so that he  D2EHPA impregnated r sin separation is  very  effective for elimination -  672  - of rare  arth elements from  La. In case  of  the (C) sample,  purity of La203 is99.996% and  La203/TREO becomes 99.9998% by both the anion exchange and D2EHPA impregnated r sin separation. It isconfirmed that all rare  arth elements could be  reduced to less than 1 mass ppm. The  impurities of ome transition elements such as Al, Cr, Mn, and Cu also reducedin this process. In addition, the total purity including rare arth elements and non-rare earth elements is better than that of commercial  5/s1 La203. Itcan be concluded that  D2EHPA impregnated resin is effective for the separation of rare arth elements  from La and anion exchange resin is useful for the separation f some transition metals. Flow sheet of  "Preparation process ofhigh  purity  La203"  issummarized  in  Fig.  1.  Finally it can be concluded that extraction chromatography using D2EHPA impregnated r sin is excellent method toseparate  rare arth elements from La and anion exchange resin is useful for the separation of some transition metals. Also, this method is a very simple process compared to the other purification methods. Accordingly, it is  confirmed that the purification process developed in this research is suitable for preparation of high  purity La203.                     Raw  Material  99.1%  Lad  HCl                     Anion Exchange Removal of Bi and some  Separation  (IM HCI)  transition  imptuiti  es  4,  NH3               • IpH 3-LaC13 and  impurities  solution Extraction  Chromatography  using  D2EHRA  Impregnated  Resin   (Semi-pilot scale,  La  15g/L)Removal of rare earth elements and some  transition  imptuitiesHigh purity  LaC13 Solution-  0.15M  HClOxalate  precipitation 5Chn1(0.65mol xalate acid)  810°C, 2  hour, 02High purity La203Figure 1 Preparation process of high purity La203.— 673 —論文審査結果の要旨希土類金属は、そ の特性の多様性か らさまざまな分野への応用がな されている。特に、La203は次世代ULSIのゲー ト絶縁膜材料 として期待 されてい る。ULSIに代表 され る電子デバイスに使用 され る材料は高純度である事が要求 され るが、希土類金属元素は化学的に活性で、相互分離が困難であるために高純度化が遅れている。 さらに、希土類金属の特性解明および新たな応用範囲の開拓のためにも高純度希土類金属の作製が不可欠である。本研究は、有機抽出剤含浸樹脂 を固定相に用いた抽 出クロマ トグラフィーによる高純度La203の作製プ ロセスを開発 したもので、全5章 より成 る。第1章 は緒論 であ り、本研究の背景 と目的 について述べている。第2章 では、有機抽出剤含浸樹脂を作製 し、塩酸酸性水溶液中におけるLa、Ce、Pr、NdおよびSmの分配係数 を評価 し、希土類金属元素の相互分離の可能性を調べている。抽出挙動の異なる3種 類の有機抽出剤、Cyanex923、D2EHPAおよびPC88Aに注 目し、これらを市販のポー ラス樹脂 中に含浸 させ、固定相 と水溶液相の体積比およびpHを変化 させて分配係数の評価を行った。その結果、D2EHPA含浸樹脂がLaからの希土類金属不純物の分離に適 していることを明らかに している。第3章 では、D2EHPA含浸樹脂 を用い、希土類金属に多く含まれ る非希土類金属不純物の分配係数および分離定数を評価 し、抽出挙動の考察と、カラム法による分離条件 を明らかに している。抽出挙動は溶媒抽出の場合 と同等であること、カラム法に よる分離が可能であることを明らかにした。特に、カラム法による分離では、実操業 を目的 とした、Laの高濃度水溶液を用いた場合に生 じるpH変化の問題を解決 してい る。第4章 では、カラムのスケールアップを行い、高純度La203を作製 し、その純度 を評価 している。スケールアップ時に生 じる問題を克服すると共に、抽出クロマ トグラフィーでは除去が困難なBi分 離に対 して陰イオン交換法を適用 し、分離プロセスを構築 した。 さらに、高純度化 されたLa塩 化物水溶液か らシュウ酸沈殿法によ り得 られたシュウ酸塩 を蝦焼することで高純度La203を作製 した。その結果、得 られた高純度La203の純度は99.996%であ り、希土類金属のみを考慮 した場合の純度 として、これまでの値 を上回る99.9998%を達成 している。第5章 は結論で、本研究で得 られた成果 を総括 している。以上要す るに、本研究は、抽出クロマ トグラフィーにより、これまで困難であった希土類金属の相互分離 を目的 とした基礎実験 を行い、高純度La203を作製できるプ ロセスを開発 した もので、材料工学の発展に寄与するところが少なくない。よって,本 論文は博士(工学)の学位論文 として合格 と認める。674

Purification of La by Extraction Chromatography (抽出クロマトグラフィーによるランタンの高純度化)

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Purification of La by Extraction Chromatography (抽出クロマトグラフィーによるランタンの高純度化)

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