PURPOSE: To improve the collection ratio of TiO2 and the filterability of the reaction product by adding the excessive sulfuric acid to the metal forming the sulfate in the mixture of the titanium ore and the titanium slag, and heating the mixture.
CONSTITUTION: Sulfuric acid of 60-80wt.% concentration corresponding to ≥2.5 times the stoichiometric amount is added to the metal forming the sulfate in the mixture of 40-80wt.% titanium ore and 20-60wt.% titanium slag, and decomposition is achieved at 130-180°C. The seed of 0.5-5wt.% is preferably present for the amount of the metallic sulfate to be generated during the decomposition. After the decomposition is completed, the residual and excessive sulfuric acid is re-used in a cyclic manner. The use of mixture the titanium ore and the titanium slag is essential not only for the improvement of the collection ratio of titanium, but also for the improvement of the filterability of the crystal of the generated metallic sulfate, the cleaning quality, the peelability of the cake, and the separation and collection of the excessive sulfuric acid can be easily achieved thereby, enabling the re-use in a cyclic manner.
WATANABE NOBUO
ISHII JUNYA
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