US 5,023,061 A · Chromatographic separation of zirconium isotopes with anhydrous readily recyclable eluents

Abstract

The isotopes of zirconium can be partially or completely separated by loading an essentially anhydrous alcoholic solution of an ionic compound of zirconium onto a cationic exchange resin with pentavalent phosphorus derived active groups which serves as the stationary phase of a chromatograph, eluting the compound with an essentially anhydrous alcoholic solution of hydrogen chloride and collecting distinct elution volumes representative of each isotope. In a preferred embodiment, the active groups of the cation exchange resin are derived from di-2-ethylhexyl phosphoric acid, tri-n-octyl phosphine oxide or tributyl phosphate and the chromatograph is of a type, such as a continuous annular chromatograph that it can be operated in a continuous steady state manner.

Claims22

Dependent claims

A process for reducing the thermal neutron cross-section of zirconium by increasing the concentration of the low cross-section isotopes and decreasing the concentration of the high cross-section isotopes which comprises subjecting an essentially anhydrous alcoholic solution of an ionic zirconium compound with a higher than desired distribution of high cross-section isotopes to continuous steady state chromatography utilizing a cation exchange resin with pentavalent phosphorus derived active groups as the stationary phase, collecting at least two product fractions, one enriched in zirconium 90 and the other enriched in zirconium 94, and combining them to yield a zirconium with a lower cross-section than the starting zirconium.

A commercial process for obtaining zirconium with a reduced thermal neutron cross-section by increasing the concentration of the low cross-section isotopes and decreasing the concentration of the high cross-section isotopes which comprises

1) preparing an essentially anhydrous alcoholic solution of zirconium tetrachloride with a natural isotope distribution to a solution strength of at least about one molar,
2) subjecting this solution to continuous steady state chromatography in a continuous annular chromatograph wherein
a) the eluent is a between about 1 and 4 molar essentially anhydrous alcoholic solution of hydrogen chloride,
b) the stationary phase comprises a cation exchange resin which has
i) pentavalent phosphorus derived active groups,
ii) a capacity for complexing with the zirconium compounds present of between about 0.01 and 0.5 milliequivalents per milliliter under the elution conditions,
iii) a monodisperse particle distribution of approximately spherical beads with an average particle size of about 25 microns or less, and
iv) a separation factor, for zirconium 90 for a 25 cm theoretical stage of at least about 1.05, under the elution conditions,
c) the effective height of the stationary phase is sufficient to yield a zirconium 90 product fraction which comprises 98 mol percent of zirconium 90, and
3) collecting the two product fractions comprising mainly zirconium 90 and zirconium 94, respectively.

7 more elements

Dependencies are inferred from the claim text.

Chromatographic separation of zirconium isotopes with anhydrous readily recyclable eluents

Life of this patent

Chromatographic separation of zirconium isotopes with anhydrous readily recyclable eluents

Life of this patent

Abstract

Claims22