Plutonium processing liquid, oxidizers

The principle of the electrorefining process is basically simple plutonium is oxidized at a liquid metal anode containing impure metal feed and the resulting Pu+3 ions are transported through molten salt to a cathode where pure metal is produced. 

Americium is separated from plutonium by a liquid-liquid extraction process involving immiscible molten salt and molten plutonium metal phases. The molten salt extraction process is based upon equilibrium partitioning (by oxidation-reduction reactions) of americium and plutonium between the molten chloride salt and molten plutonium metal phases. 

The principle of the electrorefining process is basically simple plutonium is oxidized at a liquid metal anode containing impure metal feed and the resulting Pu ions are transported through molten salt to a cathode where pure metal is produced. The transport salt is usually eutectic NaCl-KCl but NaCl-CaCl2 can also be used. As liquid plutonium metal builds up on the cathode it drips off into an annular channel surrounding the anode cup where it coalesces into a pool of metal and is recovered after the cell is cooled. The entire chemical process is performed in a molten salt bath. 

Salt Transport Processing (8, 9, 10, 11) The selective transfer of spent fuel constitutents between liquid metals and/or molten salts is being studied for both thorium-uranium and uranium-plutonium oxide and metal fuels. The chemical basis for the separation is the selective partitioning of actinide and fission-product elements between molten salt and liquid alloy phases as determined by the values of the standard free energy of formation of the chlorides of actinide elements and the fission products. Elements to be partitioned are dissolved in one alloy (the donor... 

Preliminary studies have shown that ionic liquids have potential as solvents and electrolytes for metal recovery, and the feasibility of these solvents has been demonstrated for the extraction of gold and silver from a mineral matrix [7], the recovery of uranium and plutonium from spent nuclear fuel [8], and the electrodeposition and electrowinning of metals (especially, for active metals such as Li, Na, Al, Mg, and Ti) from ionic liquids [9-11], Ionic liquids as green solvents and electrolytes have shown important and potential application in extraction and separation of metals. In this chapter, the new applications and the important fundamental and appUed studies on the extraction and separation of metal in ionic liquids including metal oxides and minerals or ores processing, electrodeposition of metals (mainly for active metals), and extraction and separation of metal ions are described. 

PuOj from direct calcination of Pu(N03 )4. The precipitation steps of the above processes can be avoided by the direct calcination of the plutonium nitrate solution to PuOa. Calcination has been carried out at 350 C in a liquid-phase screw calciner. Half a mole of ammonium sulfate per mole of plutonium is added to the feed solution to increase the production of reactive PuOi. The calcination time and temperature must be low enough to minimize sintering, which would otherwise reduce the chemical reactivity of the oxide particles for subsequent conversion to a halide. 

---