Purification process

Abstract

A process for purifying Mo-99 from an acidic solution obtained by dissolving an irradiated solid target comprising uranium in an acidic medium, or from an acidic solution comprising uranium and which has previously been irradiated in a nuclear reactor, or from an acidic solution comprising uranium and which has been used as reactor fuel in a homogeneous reactor, the process comprising contacting the acidic solution with an adsorbent comprising a zirconium oxide, zirconium hydroxide, zirconium alkoxide, zirconium halide and/or zirconium oxide halide, and eluting the Mo-99 from the adsorbent using a solution of a strong base, the eluate then being subjected to a subsequent purification process involving an alkaline-based Mo-99 chromatographic recovery step on an anion exchange material. Also provided is apparatus for carrying out the process.

Claims

1. An apparatus for carrying out a process for purifying Mo-99, the apparatus comprising: a column or vessel containing an adsorbent comprising a zirconium oxide, zirconium hydroxide, zirconium alkoxide, zirconium halide and/or zirconium oxide halide; a source of a solution of a strong base, the source of strong base solution being arranged in fluid communication at an inlet of the column or vessel containing the adsorbent; a column or vessel containing an anion exchange material on which Mo-99 can be quantitatively adsorbed and arranged in downstream fluid communication with the column or vessel containing the adsorbent; a source of a solution of an acid, the source of acid solution being arranged in fluid communication at an inlet of the column or vessel containing the anion exchange material; and a column or vessel containing MnO.sub.2 material and arranged in downstream fluid communication with the column or vessel containing the anion exchange material; a source of a solution of sulfuric acid containing thiocyanide ions and a reducing agent, the source of sulfuric acid solution containing thiocyanide ions and a reducing agent being arranged in fluid communication at an inlet of the column or vessel containing the MnO.sub.2 material; and a column or vessel containing an ion exchange material comprising iminodiacetate groups and arranged in downstream fluid communication with the column or vessel containing the MnO.sub.2 material.

2. An apparatus of claim 1, wherein the adsorbent further comprises a titanium oxide and/or silicon oxide.

3. An apparatus of claim 1, wherein the zirconium compound is present at a concentration of from 5 to 70 mol % of the adsorbent.

4. An apparatus of claim 1, wherein the adsorbent is in the form of pellets.

Description

EXAMPLE 1

U (Low Enriched Uranium)-Foil Process

(1) A quantity of U-metal foil is dissolved in an appropriate solution of nitric acid, as described in chemical equation (1), in order to produce a final uranium concentration of 150 g/L and a final pH of the solution equal to 1.
U.sub.metal+4HNO.sub.3.fwdarw.UO.sub.2(NO.sub.3).sub.2+2H.sub.2O+2NO.sub.(g)[1]

(2) The final solution, which contains Mo-99 among other isotopes, is conducted through a column containing one of the Zr-containing sorbents, for instance Termoxid T52 (see FIG. 1Mo-99 extraction). With an appropriate flow the loading of this column may take around 30 to 60 minutes. After the loading procedure, Mo-99 is retained in the column together with traces of U and other fission products. The column is then washed with a solution of 0.1M HNO.sub.3 with a volume corresponding to eight column bed volumes. This washes out almost all U retained in the column. The Mo-99 elution can be done using a solution of NaOH (1M), preferably using a maximum of three column bed volumes. This solution is then further purified using the AG 1.times.8 sorbent, as described by Sameh and Ache.

EXAMPLE 2

Homogeneous Reactor

(3) Following the teachings of U.S. Pat. No. 5,596,611, a uranyl nitrate (UO.sub.2(NO.sub.3).sub.2) solution follows the same procedure as described in Example 1. Since the homogeneous reactor solution is typically much larger than the one obtained by dissolving U-metal foil targets, the solution flow speed should be adjusted to maintain the total loading time. Both rising and elution steps are equivalent for both methods.

(4) All documents cited above are hereby incorporated herein by reference in their entirety.