A Comparative Experimental Analysis of the Effect of Spiral Geometry on the Separation of Fine Chromite Particles. Part 1: Potential Downstream Impacts

This study focuses on examining the separation performance of spirals employed in a classified fine-sized (− 200 + 2 5 µm) chromite ore. Dwindling global reserves of high-grade chromium ores and dispersing minerals in the form of fine particles make it attractive to find alternative and efficient methods for enriching these minerals in an economically as well as environmentally sustainable manner. Experimental tests were conducted on three spiral concentrators with distinct geometries. The effects of pulp density, flowrate, and splitter blade positions on the separation efficiency and enrichment ratios were thoroughly examined. The separation variables were comparatively assessed, and response surface method (RSM) was employed for optimization. The results indicated that optimal separation performance was achieved using a small diameter spiral (Ø: 60 cm), whereas the least effective separation occurred in a large diameter spiral (Ø: 100 cm) with a lower pitch angle. The findings revealed that high flowrates and pulp densities adversely affected the separation efficiencies, and the positions of the splitters significantly impacted the quality of the obtained products.