In-Plant Testing of the Hydrofloat Separator for Coarse Phosphate Recovery
The HydroFloat technology was specifically developed to upgrade phosphate sands that are too coarse to be efficiently recovered by conventional flotation methods. In this novel process, classified feed is suspended in a fluidized-bed and then aerated. The reagentized phosphate particles become buoyant and report to the product launder after encountering and attaching to the rising air bubbles. Simultaneously, the hydrophilic particles are rejected as a high solids content (65-70%) underflow. The fluidized bed acts as a “resistant” layer through which no bubble/particle aggregates can penetrate. The HydroFloat can treat much coarser particles as compared to traditional flotation processes since it is actually a density separator. In addition, the high solids content of the teeter bed promotes bubble-particle attachment and reduces the cell volume required to achieve a given capacity. To verify the advantages of the HydroFloat technology, a 5-tph circuit was installed and evaluated at PCS Phosphate’s Swift Creek beneficiation plant. Feed to the test circuit was continuously classified, conditioned, and upgraded in the HydroFloat separator. The test results indicate that the HydroFloat can produce a high-grade phosphate product in a single stage of separation. Product quality ranged between 70-72% BPL and 5-10% insols. BPL recoveries exceeded 98% at feed rates greater than 2.0 tph per ft2 of separator cross-sectional area.