| abstract |
Purification techniques have been developed for ceramic powder precursors, e.g., barium nitrate. These techniques can be performed using one or more of the following operations: ( 1 ) removal of impurities by precipitation or coprecipitation and separation using a nonmetallic-ion-containing strong base, e.g., tetraalkylammonium hydroxides; ( 2 ) reduction of higher oxidation-state-number oxymetal ions and subsequent precipitation as hydroxides that are separated from the solution; and ( 3 ) use of liquid-liquid exchange extraction procedures to separate certain impurities. |