Applied mineralogical characterization of ilmenite from Kahnuj placer deposit, Southern Iran

摘要

Kahnuj placer deposit contains ilmenite and magnetite as the main valuable minerals. Microscopic and microprobe analyses show that ilmenite occurs in two forms as individual grains and exsolved lamellae within magnetite. Exsolved lamellae of hematite, sphene of different shape and rare rutile and zircon are found as inclusions in ilmenite. According to microprobe analysis data the TiO2 content of ilmenite (52.1 wt%) with small amounts of Mg and Mn and is very close to the theoretical one (52.6 wt%). Based on the XRF analysis, the maximum content of TiO2 in the purified ilmenite concentrate without any gangue minerals is obtained at 44 wt%. The low grade of TiO2 in the purified ilmenite is attributed to the presence of sphene and hematite inside ilmenite. The presence of sphene as a source of Ca and Si can negatively affect the quality of ilmenite concentrate and the further product titanium dioxide manufactured via chloride and sulphate routes. It is found that the magnetite from the deposit contains about 1.5 wt% of V2O3 and can be considered as important source for extraction of vanadium as a by-product.