Optimization of Process Variables for the Catalytic Reduction of U(VI) over Pt/SiO2 using Hydrazine as Reducing Agent - Design of Experiments Approach

In PUREX process, uranous nitrate has been employed for the reduction of Pu(IV)to Pu(III).Fast generation of U(IV) with high yield is very much crucial for reprocessing of plutonium-rich fuels.In the present work, a catalytic method for the preparation of U(IV) from U(VI) using hydrazine as a reducing agent over Pt/SiO2 catalyst surface was studied.The effect of various process variables on the efficiency of catalysis was studied and the process variables were optimized by design of experiments approach. Initial screening was carried out by Definitive Screening Design (DSD) to identify the variables that influence the reaction significantly, and later, these significant variables were optimized by Central Composite Design (CCD). A second-order mathematical model was derived from response surface methodology (RSM) that relates the response (% reduction of U(VI)) as a function of significant variables. The model was validated experimentally to achieve 95 % U(IV) yield within 60 minutes.