PARTICLE SIZE REDUCTION DURING ULTRASONIC PRECIPITATION OF THORIUM OXALATE

摘要

Slurries of thorium oxide used in the Homogeneous Reactor (HR) require that the particles be of uniform micron size (a size of about 2 microns is preferred), since the size of the thorium oxide particles is dependent on the size of oxalate from which it was prepared. An experimental investigation of applied ultrasonic vibration during thorium oxalate precipitation was conducted to determine the possibility of achieving smaller size, narrow size range, and freedom from exacting precipitation conditions.nSeveral precipitation vessels were examined with various means of coupling the ultrasonic energy mechanism to the chemical reaction system. It was found that the converging coupler design was the most effective. Both batch methods and continuous-flow Jet precipitation were investigated. Among the variables studied were frequency, power, temperature, concentration of chemical components, and time of ultrasonic application, processing flow rates, and mode of addition of the reagents. Evaluation was carried out by microscopic examination, gravity sedimentation, and Whitby centrifuge analysis.