Abstract: Zirconium tetrachloride containing hafnium tetrachloride is selectively reduced with liquid metallic tin to produce zirconium trichloride. The hafnium tetrachloride is then separated as a vapor from a slurry of zirconium trichloride and other solids, including stannous dichloride, in liquid metallic tin.

Abstract: Hafnium dioxide contaminated with 0.1 to 1 weight percent uranium dioxide is contacted with an aqueous acid such as nitric acid, hydrochloric acid, sulfuric acid and mixtures thereof to leach the uranium dioxide from the hafnium dioxide, thereby producing a slurry of a uranium-containing leachate containing hafnium dioxide solids. The slurry is filtered to separate the uranium-containing leachate from the hafnium dioxide solids, which are then dried to produce hafnium dioxide containing less than about 0.005 wt % uranium dioxide. The hafnium dioxide may then be released for uncontrolled commercial uses.The separated uranium-containing leachate is neutralized to precipitate uranyl hydroxide, which is then separated from the leachate. The uranyl hydroxide may be processed to produce uranium-containing products or may be disposed of as radioactive wastes having a fraction of the total volume of radioactive wastes which would need to be buried if the hafnium dioxide could not be recovered for commercial uses.

Abstract: Spent HF-HNO.sub.3 pickle acid containing (ZrF.sub.6).sup.-2 is regenerated by the addition of NaNO.sub.3 to precipitate Na.sub.2 ZrF.sub.6. The Zr.sup.+2 concentration of the pickle acid may be reduced from about 25 gram/liter to about 1 gram/liter with an increase in Na.sub.+ concentration of less than about 200 ppm. The relatively pure pickle acid containing zirconium and sodium may be recycled to pickle zirconium based articles or may be fed to a zirconium recovery process.

Abstract: A spent pickling solution containing a relatively small percentage of hydrofluoric acid and used for pickling zirconium or hafnium so as to be saturated with zirconium or hafnium fluoride, is treated by the addition thereto of sodium sulfate, Na.sub.2 SO.sub.4, to precipitate sodium zirconium or hafnium fluoride. The remaining solution is recycled for further pickling use, and may have fluoride concentration increased by the addition of calcium fluoride thereto resulting in the precipitation of calcium sulfate.