Upgrading of low-grade titanium ores by high-intensity magnetic separation: A case study from Eskişehir, Türkiye
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Istanbul Technical University
Publication date: 2026-09-01
Physicochem. Probl. Miner. Process. 2026;62(20th Balkan Mineral Processing Congress 5):235920
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Titanium is a strategic critical raw material whose supply is dominated by ilmenite and rutile-rich heavy mineral sands and leaving fine-grained, hard rock occurrences largely unexploited. This study presents the first systematic physical beneficiation investigation of a representative primary titanium ore from the Eskişehir region (northwestern Türkiye), in which titanium is hosted predominantly by non-magnetic titanite (sphene) and rutile intimately intergrown with an iron rich silicate–oxide gangue. The run-of-mine ore, grading 4.07% TiO₂ in a matrix dominated by SiO₂ (36.09%) and Fe₂O₃ (24.11%), was characterized by XRF, polarized light microscopy, and XRD, and upgraded through a reverse magnetic separation approach in which the iron-bearing gangue is rejected into the magnetic fraction. Magnetic separation tests across a range of particle sizes revealed a strongly liberation-controlled response, with effective separation achieved only below 0.106 mm. Under optimum conditions—ore ground to 100% passing 0.106 mm and processed in a two-stage Carpco wet high-intensity magnetic separator (WHIMS) at 7,000 and 11,000 Gauss—a non-magnetic concentrate grading 12.78% TiO₂ was obtained at a recovery of 53.7%, representing an approximately threefold upgrade while rejecting 95.4% of the total iron into the tailings. Semi-quantitative XRD confirmed titanite (23.9 wt%) as the dominant titanium-bearing phase, with ilmenite limited to only 3.1%, demonstrating the high selectivity of the reverse separation strategy. The results establish an effective, reagent-free pre-concentration route for Eskişehir primary titanium ores and provide a mineralogically grounded basis for the further metallurgical development of Türkiye's domestic hard-rock titanium resources.