Uranium cation exchange resins

In third separation, thorium is retained on a cation-exchange resin while uranium is eluted from the resin column. Thorium is then eluted as an oxalate complex and evaporated on a planchet for counting. The planchet is flamed to volatilize the oxalic acid and then counted. 

The activity was transported to ARCA II with a He(KCl) gas-jet within about 3 s. After deposition on a titanium slider it was dissolved and washed through the 1.6x8 mm column (filled with the cation-exchange resin Aminex A6, 17.5 2 pm) a flow rate of 1 mL/min with 0.1 M HNOj/5-10 4 M HF. 85% of the W elute within 10 s. Neither divalent or trivalent metal ions nor group-4 ions are eluted within the first 15 s. Also the pseudo-homologue uranium, in the form of U022+, is completely retained on the column. 

Natural waters Sample concentration by cation-exchange resin, separation by ion-exchange resin and complexation with Arsenazo III Spectrophotometry (total uranium) 0.1 fjg/L 80% Paunescu 1986... 

A study of the kinetics of the separation of the uranium isotopes and by uranium(iv)-uranium(vi) chemical exchange on cationic exchange resins in sulphuric acid has demonstrated that large-scale uranium enrichment by this method would be uneconomical. The sorption of uranium from highly concentrated nitric acid solutions on AMP resins has been shown to be variable and dependent on concentration. 

There exist large amounts of published experimental works dealing with enrichment of the metal isotopes (from lithium to uranium) by chromatography on cation-exchange resins. Here, we will present some optimistic and interesting examples. 

Solid 002(0211302)2 (natural uranium) was Irradiated with thermal neutrons for 10 min (flux not given) and the target was dissolved In concentrated hydrochloric acid. The solution was boiled for several minutes and was then made. 2-3 molar In the acid. A copper foil was introduced Into the solution and the fission product tellurium plated out on the foil. The coated foil was dissolved In 1 M nitric acid and passed through a cation exchange resin column (resin not designated) to remove the copper. The eluate was made basic with ammonia water. Iodide carrier added, and permitted to grow In for 70 m1n. The Iodide was oxidized to the free element and a number of I2 - I redox cycles were carried out. The Iodine was finally precipitated as the silver salt. 

The elution peak positions of a number of Ions including uranium (IV) and (Vl) are given In figure 75 for various hydrochloric add concentrations. The conditions under which the peodc positions were determined are described in the figure caption. lonescu, et al. have studied the effect of acetone on the distribution of several elements between cation exchange resins, KU-2 and H-21, and dilute hydrochloric acid solutions. 

The adsorption of uranium and other actinide elements by cation exchange resins from nitric and hydrochloric acid solutions. 

Figure 76. The adsorption of uranium hy Dowex-50 cation exchange resin from solutions of sodium sulfate, sodium acetate, and oxalic acid-. After T. Ishlmorl and H. Okuno, reference 568,... 

PEI derivatives have proven to be effective carriers of cations in Hquid membrane systems (404). This technology led to the development of ion-exchange resins (405), which are also suitable for extracting uranium from seawater (406). 

Phosphate. Because of interference by uranium in the usual magnesium ammonium orthophosphate procedure,5 uranium is first removed by a cation-exchange procedure. A column (2.5 by 36 cm.) of 50 to 75 cc. of Dowex-50 resin is washed with 200 ml. of Z N hydrochloric acid and then 200 ml. of water at flow rates of 2 to 3 ml./min. An acidic solution of the product, containing 100 to 150 mg. of orthophosphate, is passed through the column at a rate of 1 ml./min. The column is washed with water until the washings are neutral to litmus, and phosphate is determined in the combined eluate and washings by the usual gravimetric procedure.6 Uranium can be eluted from the... 

---