| 摘要 |
PURPOSE:To efficiently and easily regenerate a sulfuric acid high in concn., and low in impurities by subjecting the waste sulfuric acid containing metal sulfate to a solvent extraction treatment and subjecting the treated liq. by extraction from which titanium is extracted and removed, to a diffuse dialysis treatment. CONSTITUTION:The waste sulfuric acid containing the metal sulfate discharged from the production stage of titanium oxide is cooled and filtered preferably, and after removing a separated ferric sulfate, the waste sulfuric acid is adjusted to 15-35wt.% of free sulfuric acid. This waste sulfuric acid is subjected to the solvent extraction treatment using acidic phosphate diester, etc., to extract titanium in the waste sulfuric acid. Then, the treated liq. by extraction to the order of less than 0.5g/l titanium is subjected to the diffuse dialysis treatment using an ion exchange membrane. In this way, the impurities such as iron and chromium inclusive of the titanium in the waste sulfuric acid are removed, and the sulfuric acid less in impurities is obtained efficiently. The other hand, the org. solvent containing the titanium obtained by the solvent extraction treatment is inversely extracted with an alkali soln., then brought into contact with the dialysis remaining liq. generated by the diffuse dialysis treatment, and an alkali ion is inversely extracted to a water phase and can be regenerated.
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