METHOD OF PURIFYING ZIRCONIUM FROM HAFNIUM Russian patent published in 2012 - IPC C22B34/14 C01G25/04 B01D7/00 

FIELD: chemistry.

SUBSTANCE: method of separating zirconium and hafnium involves sublimation by heating the starting zirconium tetrafluoride containing hafnium tetrafluoride and desublimation of the formed vapour. Before sublimation, fluoride vapour is passed over or through a layer of zirconium dioxide containing not more than 0.03 wt % hafnium. The height of the layer when passing zirconium dioxide through the layer is equal to 140-150 mm and 1950-2100 mm when passing zirconium dioxide over the layer.

EFFECT: separation of zirconium and hafnium in a single step in a single apparatus; the process itself is wasteless since the hafnium dioxide formed during the reaction is an intermediate product for producing hafnium metal.

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