Pyrochemical behavior of phosphates for spent electrolyte recycling

Kofuji, Hirohide  ; Sawada, Nobuyuki*; Sasaki, Kazuya*; Amamoto, Ippei; Myochin, Munetaka; Suzuki, Akihiro*; Terai, Takayuki*

Adaptation of the phosphate conversion technique has been evaluated to recycle the spent electrolyte generated from metal electrorefining process which is a kind of pyrochemical reprocessing technologies. In the process, accumulated impurities such as fission products are precipitated as phosphate by adding lithium phosphate and separated from the molten salt. The conceptual flow sheet has been discussed based on the thermodynamic property of constituent. However few thermodynamic data have been published relating to the phosphate, they were attempted to be derived from the results of calorimetry and thermal analysis. In this study the enthalpy and the heat capacity were estimated with lithium phosphate and some FP phosphate and the phosphate conversion reactions were evaluated.