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

This study investigates the feasibility of using a triboelectrostatic belt separator (TBS) as a dry alternative to conventional magnetic separation for concentrating apatite from a phyllosilicate-rich phosphate ore from the Unidade de Mineração de Angico, Brazil. The testing material contained 22.9% P2O5 and exhibited over 90% mineral liberation even at coarse fractions (+0.6 mm), being mainly composed of apatite and Mg/Al-bearing phyllosilicates. Pilot-scale experiments were carried out in an M6c TBS, evaluating operational parameters such as electrode polarity, belt speed, feed rate, and electrode gap. In the rougher stage, apatite’s positive charging behavior enabled separation from negatively charged gangue, with optimal conditions (run 4) producing a concentrate of 25.3% P2O5 at 85.1% recovery. Cleaner experiments further upgraded product quality, with runs 15 and 18 yielding concentrates of 29.0% and 28.9% P2O5 and overall P2O5 recoveries of 69.3% and 74.5%, respectively. Compared to high-intensity magnetic separation currently applied at the industrial plant, the TBS achieved superior mass and P2O5 recoveries and more effective MgO removal, although Fe2O3 and Al2O3 contents remained slightly above market thresholds. These results confirm the technical feasibility of triboelectrostatic separation for phosphate beneficiation, offering environmental benefits through reduced water consumption and tailings generation. Further research should focus on finer particle sizes (−0.3 mm), electrode design, and surface charge modifiers to enhance industrial performance.