Single-stage recovery and concentration of mineral sands using a REFLUX™ Classifier

The REFLUX™ Classifier is a gravity separation device that consists of a system of inclined channels located above a fluidized bed. Here we report for the first time the results obtained processing a minerals sands feed using narrow 6 mm channels that promote a laminar-shear separation mechanism that enhances the separation based on density. The feed had a head grade of approximately 5 wt% heavy minerals of density greater than 2800 kg/m³, with the majority in the size range from 50 to 150 µm. The overall recovery of the heavy minerals component was approximately constant at 85% for solids throughputs of 10-18.5 t/(m² h). The unrecovered heavy mineral had an average density close to that of the gangue, hence was deemed unrecoverable by gravity separation. The recovery of the denser and more liberated zirconium mineral exceeded 95%. So this work demonstrated the potential for the heavy mineral to be upgraded by a factor of 16 or more in a single stage operation.