Dry Concentration of Phosphate Ore by Using a Triboelectrostatic Belt Separator in Pilot Scale

This study investigates the application of triboelectrostatic belt separator (TBS) as an alternative to conventional magnetic methods for concentrating apatite from a complex phosphate ore rich in phyllosilicates. The testing material, containing 22.9% P₂O₅ and exhibiting over 90% mineral liberation even in coarser fractions (+0.6mm), was mainly composed of apatite and Mg/Al-bearing phyllosilicates, with minor quantities of car-bonates, amphibole, and feldspar. Pilot-scale experiments using an M6c TBS model were conducted in rougher and cleaner stages. Apatite’s strong tendency to acquire a positive charge enabled selective separation from the negatively charged gangue. Under optimal rougher conditions (run#4), the process yielded a concentrate with 25.3% P₂O₅ and 85.1% recovery. Subsequent cleaner tests improved product quality, with two configurations (run#15 and run#18) producing final concentrates assaying 29.0% and 28.9% P₂O₅ and overall P₂O₅ recoveries of 69.3% and 74.5%, respectively. Compared to high-intensity magnetic separation conducted at Unidade de Mineração de Angico, TBS demonstrated superior mass and P₂O₅ recoveries and improved MgO removal, although R₂O₃ levels remained slightly above commercial limits. These findings point out TBS as a viable, efficient, and selective technique for apatite concentration. Future research should focus on finer particles (-0.3 mm), electrode configurations, and charge-modifying agents to further enhance performance and industrial applicability.