Recovery of uranium values from waste

Claim 1

A PROCESS FOR THE RECOVERY OF URANIUM VALUES FROM WASTE MATERIALS CONTAINING SILICA AND METAL VALUES, INCLUDING URANIUM AND CHROMIUM, WHICH COMPRISES HYDROFLUORINATING THE WASTE MATERIAL AT A TEMPERATURE WITHIN THE APPROXIMATE RANGE OF 500* TO 600* C. WITH HYDROGEN FLUORIDE VAPOR WHEREUPON VOLATILE SILICON TETRAFLUORIDE IS FORMED AND METAL VALUES, INCLUDING URANIUM, ARE CONVERTED TO NON-VOLATILE FLUORIDES, REMOVING THE RESULTINGLY EVOLVED SILICON-TETRAFLUORIDE-CONTAINING VAPORS, THEN FLUORINATING THE HYDROFLUORINATED RESIDUE WITHIN THE TEMPERATURE RANGE OF ABOUT 400* TO 500* C. WITH FLUORINE GAS WHEREUPON VOLATILE FLUORIDES OF URANIUM, CHROMIUM AND SILICON ARE FORMED AND EVOLVED, RECOVERING THE FLUORINATION-EVOLVED VAPORS BY CONDENSATION, DISSOLVING THE FORMED CONDENSATE TO FORM AN AQUEOUS SOLUTION THEREOF, TREATING THE FORMED SOLUTION SO AS TO ELIMINATE FLUORIDE IONS, OXIDIZING THE CHROMIUM IONS PRESENT IN THE SOLUTION TO THE CHROMATE STATE, ADDING AMMONIUM HYDROXIDE TO THE OXIDIZED SOLUTION TO FORM A PRECIPITATE COMPRISING AMMONIUM DIURANATE WHILE CHROMIUM REMAINS BEHIND IN SOLUTION, SEPARATING THE FORMED PRECIPITATE AND DISSOLVING IT IN AQUEOUS HYDROCHLORIC ACID, INCOMPLETELY EVAPORATING THE FORMED AQUEOUS HYDROCHLORIC ACID SOLUTION TO SEPARATE FROM THE DISSOLVED URANIUM VALUES, BY PRECIPITATION AS SILICA, DISSOLVED SILICON WHICH MAY HAVE ACCOMPANIED THE URANIUM TO THIS POINT IN THE PROCESS, AND SEPARATING AND RECOVERING THE SUPERNATANT, URANIUM-CONTAINING SOLUTION.