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Minerals of base metals
Published in Francis P. Gudyanga, Minerals in Africa, 2020
Ilmenite is the most important commercial source of titanium [685]. It is a titanium-iron oxide mineral which is a weakly magnetic black or steel-grey solid with the idealised formula FeTiO3. It contains appreciable quantities of magnesium and manganese with the full chemical formula as (Fe,Mg,Mn,Ti)O3 and forms a solid solution with geikielite (MgTiO3) and pyrophanite (MnTiO3) which are the respective magnesian and manganiferrous end-members of the solid solution series. Leucoxene, an important source of titanium in heavy minerals sands ore deposits, is an altered form of ilmenite. It is a typical component of altered gabbro and diorite that is generally indicative of ilmenite in the unaltered rock.
Manganese ores in black shales sequences in the Western Carpathians, Slovakia
Published in Adam Piestrzyński, Mineral Deposits at the Beginning of the 21st Century, 2001
I. Rojkovič, D. Ozdin, L. Puškelová, A. Svitáčová
The Early Palaeozoic carbonates of manganese underwent the Hercynian metamorphism together with silicate minerals and manganese silicates were formed. Sedimentary rocks contained Mn-carbonate, clay minerals and quartz before metamorphism. Recent dominantly silicate character of manganese ore was formed due to metamorphism of silicates and carbonates of manganese. Metamorphosed manganese carbonate-silicate rocks „queltzites“ are characterised by presence of Mn-carbonate, tephroite and absence of low Mn-oxides especially bixbyite. Association of rhodonite, rhodochrosite, spessartite, pyrophanite, pyroxmangite and tephroite suggests epidote-amphibolite zone of Hercynian metamorphism. Rhodonite-pyroxmangite geothermometer gives 375 °C (Faryad 1991) and 390 °C (Rojkovič 1999) from Čučma deposit.
Mineralogy of beach sand in Jumundo, Korea and recovery of heavy minerals using Humphreys spiral concentrator and shaking table followed by magnetic separation process
Published in Geosystem Engineering, 2022
Hee-Young Shin, Soo-Chun Chae, Kyoungkeun Yoo
The ilmenite in the concentrate OG-5 obtained from the cross belt-type magnetic separator at 4375 G was subjected to electron probe microscope analysis (Table 5). A considerable substitution of either Mg or Mn for Fe2+ can take place leading to the end-members, namely MgTiO3 (geikielite) or MnTiO3 (pyrophanite). These minerals are rare, however, and it is more usual to find only small amounts of Mg or Mn occurring in ilmenite (Deer et al., 1965). In the Onguji area, ilmenite exists as a solid solution of (Fe, Mg, Mn)TiO3. However, it was confirmed that the contents of substitution were very small in the amount of 1.42–2.65% MnO and 0.03–0.15% MgO. The atomic ratio of the sum of Fe, Mg, and Mn ranges from 1.02 to 1.13 and that of Ti, V, and Cr from 0.94 to 0.99 based on the calculation of chemical composition of the ilmenite and oxygen number being 3.