The Separation of Rare Earths by Ion Exchange. V. Investigations with One-tenth Per Cent. Citric Acid-Ammonium Citrate Solutions<sup>1</sup>

Spedding, F. H.; Fulmer, Ellis I.; Powell, J.E.; Butler, T.A.

doi:10.1021/ja01162a004

Cited by 48 publications

(10 citation statements)

References 2 publications

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“…The limitations on (1 + e) then introduce Assumptions 3 and 4. It follows that Vr+T = (V^+ ) * ^ 1 + ) (31) and also Vt7 = Vs (yjf + l) * VT(l + I) (32) This leads to VTT7 -vr^v.…”

Section: Shapes Of Trace and Nontrace Elution Curvesmentioning

confidence: 99%

Ion-Exchange Chromatography of Trace Components

Vermeulen¹,

Hiester²

1952

Ind. Eng. Chem.

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I carry out separations of rare earths, amino acids, and other inorganic and organic materials that are not isolated easily by the older chemical procedures. The present paper will outline a quantitative calculation method for interpreting and predicting the performance of fixed-bed separation columns under the limiting condition of low relative concentration-i.e., under "trace" conditions. The proposed method is based upon a kinetic or diffusional approach and reduces under specified restrictions to a result given also by the equilibrium plate theory of Mayer and Tompkins (86).The relation of an ion exchange separation to a bulk saturation of ion exchange resin will be of interest to the general reader. As shown in the upper diagram of Figure 1, an ordinary bulk saturation operation as performed on a process liquor involves a large extent of displacement of an innocuous ion from the resin by an undesirable ion (adsorbate ion) from the feed liquor. When the column is saturated t o the extent that breakthrough of the undesirable ion occurs, the flow is interrupted and the column is then eluted or regenerated by passing through it an excess of solution of the innocuous ion. Saturation operations will be considered here only to the extent needed for deriving the theory of trace separations.The lower diagram of Figure 1 depicts an elution separation of the chromatogaphie type. In this operation only a small amount of solution containing the components to be separated is admitted to the column. These components are then washed through (eluted) by an electrolyte solution (the elutant) that initially is free of them. The components travel through the column as bands or zones a t slightly different velocities. If the column is of sufficient length the zones will draw apart completely from one another and may be recovered in the effluent as separate solutions of each individual component in carrier electrolyte. Movement of a zone through the resin occurs by the following mechanism: Liquid on the upstream (trailing) side of a zone is 1 Present address, Stanford Research Institute, Stanford, Calif. undersaturated with respect to the adsorbed component and continually takes it into solution. Passing beyond the peak of the zone to the downstream (leading) side, the same liquid is supersaturated relative to coexisting resin and hence gradually redeposits the solute component. OPERATING VARIABLESThe elution separation just described is a function of a large number of chemical and physical factors, which will be shown in this paper to be amenable to mathematical interpretations. DISTRIBUTION RATIO. This is the dimensionless ratio. DA q;Pb/CAfE which is given in Equation 4, of solute concentrations in the solid and liquid phases. The distribution ratio affects directly the rate of linear advance ( U A ) of a zone; the ratio ( R~) A of zone movement to fluid movement (I;) is given h5-In order to carry out a separation, it iF; obviously necerisary for the values DA, DB, etc., of the components undergoing elution to differ substanti...

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“…The limitations on (1 + e) then introduce Assumptions 3 and 4. It follows that Vr+T = (V^+ ) * ^ 1 + ) (31) and also Vt7 = Vs (yjf + l) * VT(l + I) (32) This leads to VTT7 -vr^v.…”

Section: Shapes Of Trace and Nontrace Elution Curvesmentioning

confidence: 99%

Ion-Exchange Chromatography of Trace Components

Vermeulen¹,

Hiester²

1952

Ind. Eng. Chem.

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“…Products and Instability Constants of Cerium, Neodymium and Ytterbium Oxalates librium constants Ce Nd Yb Aapo 0.0 X [10][11][12][13] 4.0 X 10~13 1.9 X 10-10 ASP1 5.9 X IQ-30 7.7 X 10"32 1.24 X [10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29] Ki 0.15 >90 >90 K…”

Section: Solubilitymentioning

confidence: 99%

Solubility of the Rare Earth Oxalates and Complex Ion Formation in Oxalate Solution. II. Neodymium and Cerium(III)¹

Crouthamel¹,

Martin²

1951

J. Am. Chem. Soc.

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“…Praseodymiiim, samarium and gadolinium oxides were produced in this laboratory (8,9) in which j| is the molecular weif^t of the gas* combining equations (2), (5) and (6), we obtain for the equilibrium pressure of the gas in the effusion vessel…”

Section: Hlstorloalmentioning

confidence: 99%

The vapor pressures of lanthanum and praseodymium

Daane

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The Separation of Rare Earths by Ion Exchange. V. Investigations with One-tenth Per Cent. Citric Acid-Ammonium Citrate Solutions¹

Cited by 48 publications

References 2 publications

Ion-Exchange Chromatography of Trace Components

Ion-Exchange Chromatography of Trace Components

Solubility of the Rare Earth Oxalates and Complex Ion Formation in Oxalate Solution. II. Neodymium and Cerium(III)¹

The vapor pressures of lanthanum and praseodymium

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The Separation of Rare Earths by Ion Exchange. V. Investigations with One-tenth Per Cent. Citric Acid-Ammonium Citrate Solutions1

Cited by 48 publications

References 2 publications

Ion-Exchange Chromatography of Trace Components

Ion-Exchange Chromatography of Trace Components

Solubility of the Rare Earth Oxalates and Complex Ion Formation in Oxalate Solution. II. Neodymium and Cerium(III)1

The vapor pressures of lanthanum and praseodymium

Contact Info

Product

Resources

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The Separation of Rare Earths by Ion Exchange. V. Investigations with One-tenth Per Cent. Citric Acid-Ammonium Citrate Solutions¹

Solubility of the Rare Earth Oxalates and Complex Ion Formation in Oxalate Solution. II. Neodymium and Cerium(III)¹