Americium nitrate extraction, recovery

Molten salt extraction residues are processed to recover plutonium by an aqueous precipitation process. The residues are dissolved in dilute HC1, the actinides are precipitated with potassium carbonate, and the precipitate redissolved in nitric acid (7M) to convert from a chloride to a nitrate system. The plutonium is then recovered from the 7M HNO3 by anion exchange and the effluent sent to waste or americium recovery. We are studying actinide (III) carbonate chemistry and looking at new... 

An initial experiment involving the treatment of small irradiated Pu/Al targets for the production of americium 243 and curium 244 was carried out in France in 1968 (2). The chemical process was based essentially on the use of a system comparable to the Talspeak system. After plutonium extraction by a 0.08 M trilaurylammonium nitrate solution in dodecane containing 3 vol % 2-octanol, the actinides (americium, curium) were coextracted with a fraction of the lanthanides by a 0.25 M HDEHP -dodecane solvent from an aqueous solution previously neutralized by A1(N0 ) x(0H)x and adjusted to 0.04 M DTPA. The actinides were selectively stripped by placing the organic phase in contact with an aqueous solution of the composition 3 M LiN0 -0.05 M DTPA. While this experiment achieved the recovery of 150 mg of americium 243 and 15 mg of curium 244 with good yields, the process presented a drawback due to the slow extraction of Al(III) which saturates the HDEHP. This process was therefore abandoned. 

A process for the recovery of Am (and Pu) from these concentrates, based on solvent extraction with tricapryl methyl ammonium nitrate, TCMAN (Aliquat-336, nitrate form), was developed (30), and was operated for some time in a small-scale facility equipped with pulsed glass columns at the Alkem company to produce multi-gram amounts of americium dioxide. In its final version (3JU the process worked as follows The concentrated effluents were made up to 6 to 7 moles/1 nitric acid, and the U and Pu were extracted in the first column by 0,5 moles/1 TCMAN dissolved in Solves-so-100, a high-boiling aromatic diluent. U and Pu... 

---