질산과 옥살산 용액에서 네오디뮴옥살레이트의 용해도

정동용; 김응호; 신영준; 유재형; 김종득

HWAHAK KONGHAK, Vol.34, No.4, 451-454, August, 1996

Export Citation

질산과 옥살산 용액에서 네오디뮴옥살레이트의 용해도

Solubility of Neodymium Oxalate in Nitric Acid and Oxalic Acid Media

정동용, 김응호, 신영준, 유재형, 김종득

초록

질산과 옥살산 용액 중에서 네오디뮴옥살레이트의 용해도를 구하였다. 용해도는 질산용액 중의 네오디뮴니트레이트에 옥살산을 첨가하여 네오디뮴옥살레이트를 침전시킨 후, 여과액의 네오디뮴농도를 ICP를 이용하여 분석함으로써 구하였다. 용해도는 옥살산농도가 증가하고 질산농도가 감소함에 따라서 감소하는 경향을 나타냈다. 수용액상에서 네오디뮴이 자유 옥살레이트 이온과 Nd( C₂O₄)_n^3-2n(n=1,2,3) 형태의 착물을 형성한다고하여 이에 기초한 용해도모델을 제시하였으며, 용해도 계산을 위한 용액에서의 옥살산농도, 산농도 및 이온강도를 침전반응의 화학양론적 물질수지를 이용하여 계산하였다. 필요한 각 이온들의 활동도계수는 수정된 Debye-Huckel식을 사용하여 구하였다. 옥살레이트 이온활동도가 1 X 10⁴M보다 작은 본 연구의 실험범위에서 실험치를 가장 잘 나타내는 용해도적과 안정도상수를 구한 결과 K_sp=1.6 X 10³¹, β₁=3 X 10⁷의 값이 얻어졌다.

The solubility of neodymium oxalate in nitric acid and oxalic acid media was inve- stigated. The neodymium oxalate was precipitated by addition of oxalic acid to neodymium nitrate in nitric acid solution. The concentration of neodymium in filtrate was determined by ICP(Induced Coupled Plasma Spectroscopy). The experiment revealed that the solubility decreased as the oxalic acid concentration increased and the nitric acid concentration decreas- ed. Based on the assumption, neodymium ion can react with free oxalate ion to form Nd (C₂O₄)_n^{3 -2n}(n=1, 2, 3) complex, we have proposed a solubility model of neodymium oxalate. In order to estimate the solubility of neodymium oxalate, oxalic acid, hydrogen ion concentration and ionic strength were calculated by stoichiometric material balances of chemicals in preipi- tation reaction. Also the activity coefficients of ions were calculated by the modified Debye- Huckel equation. Within the experimental range of oxalate ion activity under 1 X 10^-4M, it was obtained K_sp=1.6 X 10^-31, β₁=3 X 10⁷ which replicates the experimental data well.

Keywords:Solubility;Neodymium Oxalate;Lanthanide;Oxalic Acid

[References]

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Yoo JH, "장수명핵종 소멸처리 기술개발: 군분리공정 기술개발," Rep. No. KAERI/RR-1322/94, 한국원자력연구소 (1993)
Yoo JH, "장수명핵종 소멸처리 기술개발: 군분리공정 기술개발," Rep. No. KAERI/RR-1467/95, 한국원자력연구소 (1994)
Crouthamel CE, Martin DS, J. Am. Chem. Soc., 72, 1382 (1950)
Crouthamel CE, Martin DS, J. Am. Chem. Soc., 73, 569 (1951)
Sarver LA, Brinton P, J. Am. Chem. Soc., 49, 943 (1927)
Schubert R, Z. Physik. Chem., 67, 183 (1909)
Chung DY, Kim EH, Shin YJ, Yoo JH, Kim JD, J. Korean Ind. Eng. Chem., 6(4), 589 (1995)
Freiser H, Fernando Q, "Ionic Equilibria in Analytical Chemistry," John Wiley & Sons, New York (1963)
Debye P, Huckel E, Physik. Z., 24, 185 (1923)
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[Referenced By]

[1] Yost DM, Russell H, Garner CS, "The Rare Earth Elements and Their Compounds," John Wiley and Sons, Inc., New York (1947)

[2] Yoo JH, "장수명핵종 소멸처리 기술개발: 군분리공정 기술개발," Rep. No. KAERI/RR-1322/94, 한국원자력연구소 (1993)

[3] Yoo JH, "장수명핵종 소멸처리 기술개발: 군분리공정 기술개발," Rep. No. KAERI/RR-1467/95, 한국원자력연구소 (1994)

[4] Crouthamel CE, Martin DS, J. Am. Chem. Soc., 72, 1382 (1950)

[5] Crouthamel CE, Martin DS, J. Am. Chem. Soc., 73, 569 (1951)

[6] Sarver LA, Brinton P, J. Am. Chem. Soc., 49, 943 (1927)

[7] Schubert R, Z. Physik. Chem., 67, 183 (1909)

[8] Chung DY, Kim EH, Shin YJ, Yoo JH, Kim JD, J. Korean Ind. Eng. Chem., 6(4), 589 (1995)

[9] Freiser H, Fernando Q, "Ionic Equilibria in Analytical Chemistry," John Wiley & Sons, New York (1963)

[10] Debye P, Huckel E, Physik. Z., 24, 185 (1923)

[11] Stanislav K, Ladislav S, "Handbook of Chemical Equilibria in Analytical Chemistry," John Wiely and Sons, Inc., New York (1985)

[12] Kielland J, J. Am. Chem. Soc., 59, 1675 (1937)

[13] Davies CW, "Ion Association," Butterworths, London (1962)

[14] Davies CW, J. Am. Chem. Soc., 58, 2093 (1938)