Abstract:
The separation of zirconium and hafnium, which is essential in the
nuclear industry, is difficult due to the great similarities in their chemical
and physical properties. In contrast to the traditional aqueous chloride
separation systems, the current process focuses on dry fluoride-based
technologies, which produce much lower volumes of chemical waste. In
the present work, separation is achieved in both a sublimation and a
desublimation step, where the Zr/Hf mole ratio varies between 160 and
245 across the length of desublimer and 86 to 40 within the sublimer.
Model predictions for the sublimation/desublimation rates fit the
experimental results well, with deviations becoming more apparent as
sublimation proceeds. This may be attributed to crust formation
preventing the system from reaching thermodynamic equilibrium. The
model adequately predicts time- and temperature-dependent mole ratios of
both the sublimer residue and of the desublimed mass.
Description:
This paper
was first presented at the AMI Precious Metals
2017 Conference ‘The Precious Metals
Development Network’ 17–20 October 2017,
Protea Hotel Ranch Resort, Polokwane, South
Africa.
