20 сентября, 2015 
Pokraskin The solutions from slag digestion contain 5-6 wt.% FeSO4, and those from ilmenite digestion 16-20 wt.% FeSO4 after reduction of the Fe3+. The ilmenite solution is cooled under vacuum to crystallize and separate FeSO4 • 7 H2O (j) and reduce the quantity of FeSO4 discharged with the waste acid. The concentration of the TiO2 in the solution is thereby increased by ca. 25%. The copper salt is separated by filtration or centrifugation (k).
The iron sulfate is used in water purification, and as a raw material for the production of iron oxide pigments. Alternatively, it can be dehydrated and thermally decomposed to give iron(III) oxide and sulfur dioxide.
Due to the recent legislation in the European Union [2.32], from 2005 there will be a huge demand (ca. 1 million tons per year) for FeSO4 as chromate reducing agent for cement. This will have an enormous impact for the titanium dioxide industry,
as FeSO4, that formerly has been a waste material, will then become a commercial product.
Опубликовано в рубрике 