PHYSICOCHEMICAL PROBLEMS OF MINERAL PROCESSING, vol.55, no.4, pp.865-878, 2019 (SCI-Expanded)
In this study, an optimum beneficiation route was developed for an existing concentrator that processes low-grade chromite deposits. This objective is challenging as the grade of the ore under consideration is approximately 5%, which is the lowest grade processed in Turkey. Detailed characterization, process mineralogy and liberation studies were performed. The optimum fineness of grind was found to be 100% finer than 0.4 mm after the initial beneficiation tests. Laboratory test work was performed using a combination of a teetered bed separator (TBS), spiral concentrator and shaking table. Two different circuit alternatives including a TBS followed by only shaking tables and a combination of a spiral concentrator, TBS, and shaking tables were compared. It was found that an alternative comprising a spiral concentrator, TBS, and shaking table provided better results, required less equipment, etc. Considering these results, a provisional flowsheet was developed, and a total final concentrate of 6.8% by weight with 49.5% Cr2O3 grade and 71.51% Cr2O3 recovery could be obtained. The detailed laboratory test work was followed by plant-scale trials for the verification of the experimental findings with different circuit configurations. From roughing and scavenging spiral groups, similar to 85% of chromite could be obtained prior to the shaking table concentration, and this led to a minimum increase of 20% in the total recovery with less footprint of the plant, reduced water usage, and lower operating costs.