| 摘要 |
A process for producing titanium dioxide which discharges no waste is disclosed. In a first step, a sulfuric acid solution containing titanium ion with one or more kinds of metal ions is contacted with a first organic solvent to extract the titanium ion as a sulfuric acid complex. The organic solvent containing the extracted titanium as a sulfuric acid complex (titanyl sulfate) is contacted with an aqueous liquid to strip the titanium into the aqueous liquid and regenerate the first organic solvent. In a second step, the aqueous liquid containing the titanium is subjected to hydrolysis to form insoluble titanium hydroxide, and the titanium hydroxide is washed with dilute sulfuric acid and/or clear water. In a third step, the raffinate of extraction in the first step is contacted with a second organic solvent to extract the titanium ion and the organic solvent containing extracted titanium is contacted with water, dilute sulfuric acid solution or a dilute titanyl sulfate solution to strip the titanium, and regenerate the organic solvent.
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