Production of uranium hexafluoride by the catalysed fluorox process: pilot plant and supporting bench-scale studies

The feasibility of producing UF6 by the catalysed reaction of UF4 with oxygen (the Fluorox process) was investigated in a 150 mm diameter fluidised bed reactor and in supporting bench-scale experiments. The rate of the Fluorox reaction in batch experiments was increased by an order of magnitude with 1 to 5 per cent catalyst (containing 3 to 4 per cent platinum on alumina). The maximum UF6 production rate at 650 deg. C was 0.9 kg h-1. However, the platinum catalyst was completely poisoned after production of only 1 and 20 kg UF6 per kg of catalyst when using respectively French and British UF4. Regeneration of the catalyst was demonstrated to be technically feasible by washing with water or ammonium oxalate solution or treating with hydrogen and hydrogen fluoride at 350-650 deg. C. However, since the very fast rate of poisoning would necessitate higher catalyst concentrations and/or frequent regeneration, the catalysed Fluorox process in unlikely to be economically competitive with the direct fluorination of UF4