Dryway process

The static bed dryway process for the production of uranium tetra-fluoride involves less advanced chemical engineering techniques than, for example, fluidization. With careful design and correctly optimized operating conditions, it has been difficult to supplant, however, on purely economic grounds. Many thousands of tons of uranium tetrafluoride have been produced by this method since the Second World War in the United Kingdom and the United States alone. 

Hawthorn, E., Shortis, L. P. and Lloyd, J. E. The fluidized solids dryway process for the production of uranium tetrafluoride at Springhelds. Trans. Inst. Chem. Engineers 38, No. 4, 197 (1960). 

If the electrolytic route were used on a large scale today, it might be more convenient to manufacture uranium tetrafluoride by a dryway process from uranium dioxide, and add this to the melt, together with anhydrous potassium fluoride, i.e. 

Figure 9.2 presents a number of less commonly used stages, but all of them have commercial application in special cases. Pressure carbonate leaching of ores, which contain limestone can be cheaper than acid leaching and ion-exchange. This is followed by TBP extraction of the concentrate for final purification since any alternative would normally be based upon the same general chemical engineering principles and would only involve a different solvent. The older type of dryway process is then shown, with ammonia precipitation as the first step, since this still has applications for the production of special types of uranium dioxide. The final calcium reduction of oxide finds application on a relatively small scale, where the uranium metal product is required in powder form. 

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