| 摘要 |
The invention relates to a method for purifying impure aluminium oxide. In accordance with the invention, impure aluminium oxide is finely ground, dissolved in a concentrated acid at a raised temperature, diluted with water, and an organic solvent is added to extract organic impurities. The phases are separated, the aqueous phase containing aluminium salts settled on the bottom is filtered or centrifugated to remove undissolved components, and is used as such or further purified. Part of the organic phase is taken to combustion and part is recycled for use as a solvent in the extraction step. Aluminium salts purified with the method of the invention are suitable to be used as water purifying and retention agents.
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