Phosphates behaviours in conversion of FP chlorides

Amamoto, Ippei; Kofuji, Hirohide  ; Myochin, Munetaka; Takasaki, Yasushi*; Terai, Takayuki*

The spent electrolyte of the pyroprocessing by metal electrorefining method should be considered for recycling after removal of FP, such as AL (alkali metals), ALE (alkaline earth metals), and/or REE (rare-earth elements), to reduce the volume of HLW. Authors have been carrying out theoretical analysis and experiment showing the behaviours of phosphate precipitates so as to estimate the feasibility of the phosphate conversion method. From hitherto results, it was found that AL except Li, and ALE are unlikely formed phosphate precipitates. However, their conversion behaviours including REE were compatible with former presented theoretical analysis; in the case of lanthanum precipitate as one of REE, submicron-size particles could be observed while that of LiPO was larger; under different conversion temperatures, the precipitates were apt to grow larger at higher temperature; etc..