ABSTRACT
The Qara-aghaj hard rock titanium deposit has been located in the 36 Km at the North-West of
Euromieh, Iran. Mineralogical studies performed by XRD, XRF, Optical microscopy and SEM
studies indicated that ilmenite, magnetite and apatite are main valuable minerals. The gangue
minerals consist of the silicate minerals such as pyroxene, olivine, plagioclase and some
secondary minerals. Ilmenite in Qara-aghaj ore occurs in three forms: ilmenite grains, exsolved
ilmenite lamellae in magnetite and ilmenite particles disseminated in silicate minerals. The grain
forms liberated in 150μm are only recoverable by physical methods. The maximum content of
TiO2 in ilmenite lattice is determined 48% by EDX. Although the ore has 8.8% average grade of TiO2, the recoverable TiO2 is only about 6.72% the studied sample contained 18.3% ilmenite and the amount of recoverable ilmenite is only about 14% (6.72% TiO2). This is due to the ilmenite exsolutions and inclusions in the magnetite and silicate minerals, and the TiO2 in solid solution in the lattices of these minerals. In fact, about 77% of whole ilmenite content of the ore will be recoverable. EDX analysis showed that Fe is substituted partially in ilmenite by Mn and Mg. Some narrow lamellae of hematite are formed inside ilmenite. By analyzing of magnetite, it was found that the V2O5 content is up to 1%. V3+ is found in magnetite lattices by replacing Fe3+.
Analyzing of clinopyroxenes indicated that augite, containing Ti, is the main form of this group.
Ilmenite, apatite and magnetite are valuable minerals for production of TiO2, P2O5 and Fe, respectively and the V2O5 can be extracted from magnetite as a by-product.