| 摘要 |
<p>INVENTOR: JOSEF MAUER INVENTION: METHOD FOR PRODUCING TITANIUM DIOXIDE Titanium slag and ilmenite are subjected to a combined but separate treatment with sulphuric acid obtained by mixing different proportions of sulphuric acid having concentrations of about 98.5% by weight and about 85% by weight, respectively. The reaction mixtures have a temperature slightly below a predetermined starting temperature and the reactions are started by adding small quantities of superheated steam having a temperature above the predetermined starting temperature. The thus obtained solutions are separated from the respective treatment residues and combined. The combined solutions are further processed for obtaining titanium dioxide. The mother liquor constitutes sulphuric acid of a concentration in the range of about 23% by weight and containing metal sulphates. This mother liquor is concentrated to a sulphuric acid concentration of approximately 85% by weight and recycled. The obtained metal sulphates are roasted and the roast gases further processed to obtain highly concentrated sulphuric acid which is recycled to the titanium slag treatment whereas the excess recycled about 85% sulphuric acid constitutes the main component used for the ilmenite treatment. The weak acid obtained from the mother liquor thus is almost entirely re-used in an economical manner.</p> |
