| abstract |
Disclosed are: a process for producing sodium tungstate, which comprises supplying an oxidizing agent (4) comprising sodium nitrate or sodium nitrite and bringing a tungsten-containing material (3) into contact with the oxidizing agent (4) in an oxygen-containing atmosphere, thereby producing a reaction product (9) continuously; a method for collecting tungsten by employing the process; an apparatus for producing sodium tungstate; a process for producing an aqueous sodium tungstate solution, which comprises introducing a reducing agent into a melt (9) containing the reaction product and dissolving the melt (9) into which the reducing agent has been introduced in water; and a method for collecting tungsten by employing the process. |