Extraction of Pd by liquid tin from molten borosilicate glass containing simulated radwaste

A method of removing Pd from borosilicate glass-melt containing simulated radwaste (Pd, Mo,Cs, Sr, Zr, Nd, Ni, Fe) using Sn as the solvent metal is attempted. Varying concentration of Sn and process temperatures were investigated. The process temperature is observed to have profound influence on the extraction fraction of Pd from the glass melt to the metallic tin phase. The % extraction is found to decrease for the melts processed at and below 900 deg C. The decrease is due to the entrainment of Pd in the glass phase at low temperatures leading to the formation of Pd-rose like structures in the glass phase. Similarly, Mo, Fe and Na also form separate phases inside glass in the vitreous melt processed below 900 deg C. Samples heat-treated at 1150 deg C show a recovery of 85 % for Pd. Extraction behavior of Pd from borosilicate glass melt was also studied by using Pd(NO3)2 as precursor material instead of Pd metal powder. (author)