Recovery of gadolinium and gallium oxides

A method for recovering gadolinium and gallium oxides from by-product material which contains these oxides and various impurities comprising the steps of:

• (a) dissolving the gadolinium and gallium oxide in an acid medium,
• (b) isolating the filtrate,
• (c) precipitating gadolinium values from said filtrate by forming gadolinium oxalate,
• (d) separating, washing and drying the precipitated gadolinium oxalate,
• (e) converting the gadolinium oxalate salt from step (d) to gadolinium oxide by pyrolyzing at a temperature in excess of 800.degree. C.,
• (f) basifying the filtrate from step (b) to a pH in excess of about pH 9,
• (g) adding sulfide ion to the filtrate of step (f) and precipitating the transition metal sulfides from the aqueous solution and filtering the solids,
• (h) acidifying the filtrate from step (g) and removing remaining traces of sulfide ion from said filtrate by oxidizing same through the addition of hydrogen peroxide and thereafter adjusting the pH to about 8.5 to precipitate gallium hydroxide, and
• (i) isolating, drying and calcining the gallium hydroxide from step (h).

The method for recovering gadolinium and gallium oxides from by-product material which contains these oxides, transition metals and various other impurities comprising the steps of:

• (a) dissolving the by-product material which contains the gadolinium and gallium oxide in an acid medium,
• (b) isolating the filtrate,
• (c) precipitating gadolinium values from said filtrate by forming gadolinium oxalate,
• (d) separating, washing and drying the precipitated gadolinium oxalate,
• (e) converting the gadolinium oxalate salt from step (d) to gadolinium oxide by pyrolysis,
• (f) basifying the filtrate of step (b),
• (g) adding sulfide ion to the filtrate of step (f) to precipitate therefrom the transition metal sulfides from the aqueous solution and filtering the solids,
• (h) adding ammonium oxalate to the filtrate of step (g) to yield ammonium gallium oxalate as a precipitate, and
• (i) isolating, drying and calcining the ammonium gallium oxalate from step (h) to yield gallium oxide.