Method of purifying barium nitrate aqueous solution
First Claim
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1. A method of purifying a barium nitrate aqueous solution, the method comprising:
- providing the barium nitrate aqueous solution;
combining the barium nitrate aqueous solution with a precipitant solution to cause precipitation of first impurities, the first impurities comprising at least one of magnesium hydroxide, aluminum hydroxide, or iron hydroxide, the precipitant solution comprising tetraalkylammonium hydroxide;
separating the first impurities from the barium nitrate aqueous solution; and
following separating the first impurities, combining the barium nitrate aqueous solution with a separation solution using a liquid-liquid extraction column to remove second impurities from the barium nitrate aqueous solution, the second impurities comprising strontium ions.
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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.
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23 Claims
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1. A method of purifying a barium nitrate aqueous solution, the method comprising:
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providing the barium nitrate aqueous solution; combining the barium nitrate aqueous solution with a precipitant solution to cause precipitation of first impurities, the first impurities comprising at least one of magnesium hydroxide, aluminum hydroxide, or iron hydroxide, the precipitant solution comprising tetraalkylammonium hydroxide; separating the first impurities from the barium nitrate aqueous solution; and following separating the first impurities, combining the barium nitrate aqueous solution with a separation solution using a liquid-liquid extraction column to remove second impurities from the barium nitrate aqueous solution, the second impurities comprising strontium ions. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19)
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20. A method of purifying a barium nitrate aqueous solution, the method comprising:
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providing the barium nitrate aqueous solution; combining the barium nitrate aqueous solution with a precipitant solution to precipitate first impurities, the first impurities comprising at least one of magnesium hydroxide, aluminum hydroxide, or iron hydroxide, the precipitant solution comprising tetraalkylammonium hydroxide and having a pH in the range of 7.5 to 8.5; separating the first impurities from the barium nitrate aqueous solution; following separating the first impurities, increasing the pH of the barium nitrate aqueous solution after separating the first impurities; reducing the oxymetal ions in the barium nitrate aqueous solution to precipitate second impurities, the second impurities including ions that have an oxidation-state-number of 6 or 7 prior to reducing; separating the second impurities from the barium nitrate aqueous solution; and following separating the second impurities, combining the barium nitrate aqueous solution with a separation solution using a liquid-liquid extraction column to remove third impurities from the barium nitrate aqueous solution, the third impurities comprising strontium ions. - View Dependent Claims (21, 22)
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23. A method of purifying a barium nitrate aqueous solution, the method comprising:
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providing the barium nitrate aqueous solution; combining the barium nitrate aqueous solution with a precipitant solution to precipitate first impurities, the first impurities comprising at least one of magnesium hyroxide, aluminum hydroxide, or iron hydroxide, the precipitant solution comprising tetraalkylammonium hydroxide and having a pH in the range of 7.5 to 8.5, strontium ions substantially remaining in solution; separating the first impurities from the barium nitrate aqueous solution; increasing the pH of the barium nitrate aqueous solution to approximately 10 using tetraalkylammonium hydroxide after separating the first impurities; reducing the oxymetal ions in the barium nitrate aqueous solution to precipitate second impurities, the second impurities including ions that have an oxidation-state-number of 6 or 7 prior to reducing; separating the second impurities from the barium nitrate aqueous solution; and following separating the second impurities, combining the barium nitrate aqueous solution with a separation solution using a liquid-liquid extraction column to remove third impurities from the barium nitrate aqueous solution, the third impurities comprising strontium ions, the separation solution including decanoic acid.
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Specification