Metallurgical performance of a next generation coarse particle flotation cell in sulfide ore processing

This study evaluates the performance of a novel coarse particle flotation (CPF) cell that operates using a froth-feeding mechanism, designed to simplify operation relative to fluidized-bed systems and to enhance coarse mineral recovery without requiring feed pre-classification or fluidization. Laboratory tests were conducted on copper – gold ore using two feed size distributions: a non-classified feed (D80 = 437 µm) and a classified feed (D80 = 481 µm). Across all conditions, the froth-feeding CPF cell developed by Metso achieved high Cu and Au recoveries while rejecting a substantial proportion of gangue at particle sizes more than twice those processed in the site’s conventional flotation circuit. Feed classification had limited effect on mass pull and Au recovery, while Cu recovery showed only modest sensitivity to D80, with slightly higher recoveries obtained in the non-classified feed circuit. To investigate recovery mechanisms, High Resolution X-Ray micro computed tomography (XCT) was applied to quantify mineral surface exposure in the concentrate. Most recovered particles exhibited exposed mineral surfaces between 1% and 30%, and fewer than 10% showed no measurable exposure, indicating that entrainment contributed minimally to overall recovery. The ability of the Metso CPF cell to recover particles with as little as ~ 1% exposed mineral surface area demonstrates effective flotation of partially liberated coarse composites. Overall, the Metso froth-feeding CPF cell shows potential as a lower-complexity alternative to fluidized-bed flotation for coarse particle recovery. Its implementation may support coarser tailings production, increased plant throughput, and more efficient use of energy and water in mineral processing circuits.