| 摘要 |
PURPOSE:To obtain the titled high-purity compound useful in producing optical fiber glass etc. from which impurities such as Fe, etc., are removed, by adding NH3 to an inorganic acid aqueous solution of aluminum to form colloid of Al(OH)3 and purifying the colloid by a given treatment. CONSTITUTION:NH4OH is added to an aqueous solution of aluminum in an inorganic acid such as HNO3 etc to form colloid of Al(OH)3 and impurities (e.g. Fe and Cr) are adsorbed and precipitated on the surface of the colloid. Then the precipitate is removed to leave a supernatant liquid, which is mixed with ammonium pyrrolidinedithiocarbamate as a chelating agent, extracted with a solvent such as methyl isobutyl ketone etc., and Fe etc. are removed to give Al(NO3)2, etc. Then Al(NO3)3 etc. purified under reduced pressure by distillation method or sublimation purification method and the impurities such as Fe, Cr, etc., are reduced to a ppb level to give a high-purity aluminum compound.
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