Processing of Titanomagnetite Concentrate to Produce Slags Suitable for Further Recovery of Titanium and Vanadium

The results of studying the processing of the titanomagnetite concentrate from the Gremyakha-Vyrmes deposit intended to produce granulated iron and a titanium–vanadium slag are presented. The most suitable method for processing this concentrate is direct iron reduction in a rotary hearth furnace, a key feature of which is the concentration of vanadium along with titanium in a slag suitable for subsequent hydrometallurgical processing to recover vanadium and titanium. To perform the process in a rotary hearth furnace, a protective carbon bed should be used to prevent contact between the molten slag and the refractory lining. The influence of the reducing agent content in a charge and the reduction temperature on the composition of the resulting titanium–vanadium slag is studied under reduction roasting conditions on a protective bed. Reduction with the addition of 16% coke at 1550°C leads to the formation of a slag with the following composition (wt %): 6.2 FeO, 43.9 TiO2, 20.6 Al2O3, 2.3 V2O5, 13.2 SiO2, 7.5 MgO, 4.3 CaO, 0.6 MnO, 0.4 Cr2O3, and 0.9 (K,Na)2O. The high content of titanium in the slag and its presence in the form of anosovite n[Al2O3⋅TiO2]⋅m[(Mg,Fe)O⋅2TiO2], which is easily decomposed in sulfuric acid, allows for further processing to recover vanadium and titanium. For vanadium recovery, the slag is proposed to be processed using the well-known lime–sulfuric acid method, which involves oxidizing roasting followed by sulfuric acid leaching of calcium vanadates. For titanium recovery, hydrometallurgical methods are suggested to synthesize products suitable for producing both metallic titanium and pigment-grade TiO2.