Method of recovering tantalum from silicon-containing tantalum scrap
AssigneeTokyo Shibaura Denki Kabushiki Kaisha
InventorsHiroshi Endo, Naoyuki Hirate, Masao Tezuka
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Abstract
Disclosed is method of recovering tantalum from silicon-containing tantalum scrap, which comprises dissolving said scrap in an inorganic acid, bringing the resulting solution into contact with an anionic exchange resin, followed by washing said anionic exchange resin with (a) a solution of 3 to 10 mol/l. of hydrofluoric acid or (b) a solution of strongly acidic medium containing 0.01 to 0.5 mol/l. of hydrofluoric acid and 1 to 6 mol/l. of a strong acid, and then washing the same with an aqueous solution of a mixture composed of hydrofluoric acid, aqueous ammonia and an ammonium salt.
Claims14
A method of recovering tantalum from tantalum-containing scrap containing at least silicon and niobium as impurities to produce a recovered tantalum product containing less than about 200 ppm of silicon, consisting essentially of the steps of:
- dissolving in an inorganic acid a tantalum scrap containing at least silicon and niobium to form a solution;
- contacting said solution with an anionic exchange resin;
- first washing said contacted exchange resin with (a) a solution of about 3 to 10 mol/l of hydrofluoric acid or (b) a solution of a strongly acidic medium comprising from about 0.01 to 0.5 mol/l of hydrofluoric acid and from about 1 to 6 mol/l of a strong acid to remove the impurities;
- further washing said exchange resin with an aqueous solution of a mixture comprising hydrofluoric acid, aqueous ammonia and an ammonium salt to produce a tantalum eluate;
- and
- recovering tantalum from the tantalum eluate.
Dependencies are inferred from the claim text.