THERMODYNAMIC ANALYSIS AND EXPERIMENTAL-STUDY ON THE CHLORINATION OF URANIUM OXIDE BY GAS-SOLID REACTION

In order to determine the operating condition of an uranium chlorinati on process with U3O8-C-Cl-2 system, the experimental conditions have b een evaluated preliminarily by the thermochemical analysis and experim entally confirmed in this study. The dry-type chlorination of U3O8 occ urs as irreversible and exothermic reaction and produces many kinds of chloride compounds such as UCl3, UCl4, UCl5, and UCl6 in the air and humidity controlled argon environment. Taking account of Gibbs free en ergy and vapor pressure for various chloride compounds, the proper tem perature range of chlorination appears to be 863 to 953 K in aspects o f increasing reaction rate and the yield of nonvolatile product. In th e course of the experimental confirmation the powder of U3O8 is perfec tly converted into uranium chlorides within 4 hours above 863 K, and t hen the maximum fraction of uranium chloride remaining in the reactor is about 30% of total conversion mass.