A method of reducing trivalent iron during the production of titanium dioxide by a sulfate process

摘要

The present invention relates to a process step for reducing trivalent iron in the production of titanium dioxide by a sulfate process. According to the present invention, after separation of the poorly soluble decomposition residue, the ternary iron is reduced completely using metal iron in such a way that it is completely reduced to bivalent iron and the tetravalent titanium is selectively and partially reduced to trivalent titanium. Preferably, a Ti (III) content of 1 wt% to 5 wt%, based on total titanium, is required. The process step according to the invention is preferably carried out in a continuous reduction operation at a temperature of 50 DEG C to 85 DEG C in a reduction reactor, wherein the progress of the reduction is carried out in the presence of a redox potential or iron (III) ) Or titanium (III) content. The process according to the invention is characterized by the following advantages: the process can be existently automated, the reduction reaction proceeds constantly, different scrap qualities can be used, and improved TiO ₂ product quality is achieved.