The effect of stirring speed and reactant residence time in the bench scales CSTR on the reaction conversion of ZBS

Abstract

The bench scales continuous stirred tank reactor (CSTR) for the synthesis of zirconium basic sulfate (ZBS) is one of the prototypes of research and development for the manufacture of nuclear-grade zirconium products in Center for Accelerator Science and Technology (CAST). The use of bench scale CSTR is to reduce the impurities of U, Th, Fe, Ti from zirconium oxychloride (ZOC) at certain pH conditions through the ZBS precipitation process. The purpose of this study is to test the CSTR of bench scale for ZBS synthesis by studying the effect of stirring speed of 100, 150, 200, 250, 300 rpm and residence time of 60, 75, 90, 105, 120 min on the conversion of ZBS synthesis. The bench scales of CSTR for ZBS synthesis was carried out by reacting to a 0.2 M ZOC solution with (NH4)2SO4 0.08 M at a mole ratio of Zr/SO4- = 5/2 and the pH of ZBS formation about 1.8─2.0. The experimental results show that at a stirring speed of 250 rpm and a reactant residences time of 120 min gives a ZBS formation conversion of 0.5059. It can be concluded that the greater the stirring speed and space-time the greater the conversion of ZBS.