The use of a reflux classifier for chromite ores: assessment of different circuit alternatives at pilot scale

A set of experiments was performed using single replication and a statistical design by using a pilot scale REFLUXTM Classifier (RC300) on three different streams of an operating plant. In the present work, fluidization water rate and pressure set point were considered. Other factors, including feed rate and feed solid content, were maintained constant and were not examined. Based on the mass balanced sampling and pilot scale test results RC can give a similar performance in rejecting gangue from chromite ore compared to the existing spiral circuit. In addition to this, different concentrates can be obtained with a wide recovery/grade range by adjusting the main operational parameters. RC can produce a pre concentrate which is a grade of 18.35 Cr<sub>2</sub>O<sub>3</sub> with a 43.40% mass recovery and 87.50% chromite recovery which is very close to the performance of existing circuit. The chromite grades of sample C clearly show that the final concentrate can be upgraded by using a finishing RC. The chromite recovery comparison between the fine table and RC 300 (high grade) clearly shows that the separation mechanism and the existence of parallel inclined plates positively affect the fine particle recovery. According to the results, a new flowsheet can be designed by using the spirals and the RC. This would eliminate the need for both shaking tables and dragon tables and the required footprint. The test results revealed that RC could be suitable device as a pre-concentration and final concentration operations in chromite beneficiation plants.