Continuous anion exchange chromatography for the separation of zirconium isotopes

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 aqueous solution of zirconium oxychloride by hydrolyzing zirconium tetrachloride with a natural isotope distribution in water to a solution strength of at least about one molar,
• 2) raising the acidity of the solution to a value sufficient to assure that the zirconium atoms present become part of oxychloride anions,
• 3) subjecting this solution to continuous steady state chromatography in a continuous annular chromatograph wherein
• a) the eluant is a hydrochloric acid,
• b) the stationary phase comprises an anion exchange resin which has
• i) amino nitrogen derived active groups,
• ii) a capacity of at least about 0.05 milliequivalents per milliliter measured at a 500 micron particle size,
• iii) a monodisperse particle distribution of approximately spherical beads with an average particle size of about twenty-five microns or less, and
• iv) a separation factor, .alpha., for zirconium 90 for a 25 cm theoretical stage of at least about 1.05 under the elution conditions, and
• 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
• 4) collecting the two product fractions comprising mainly zirconium 90 and zirconium 94, respectively.