Advancing coarse particles recovery: Pilot trial of a novel flotation cell

• A novel coarse particle flotation (CPF) technology was evaluated at laboratory and pilot scale. • The system operates on the froth feeding principle, introducing feed directly into or onto the froth phase. • Tests used Aitik copper ore in a scavenger flotation configuration. • Two flowsheets were assessed: with and without feed classification of scavenger tailings. • Copper grade in +125 µm fraction was reduced from 0.052 % to 0.031 %; overall tailings from 0.017 % to 0.010 %. Coarse particle flotation (CPF) has been studied as a potential technology for improving mineral resource efficiency and supporting decarbonization. However, existing CPF systems are often complex, capital-intensive, and require substantial auxiliary infrastructure. This study presents the development and pilot-scale evaluation of a novel flotation cell based on the froth feeding principle, which represents an alternative approach for coarse particle recovery. In this configuration, feed is introduced directly into the froth phase, bypassing the slurry–froth interface and reducing drop-back losses. The technology operates using standard flotation parameters and does not require feed classification for effective performance. Continuous pilot testing was conducted at the largest copper concentrator in Europe, using scavenger tailings as feed. Two flowsheets were assessed: unclassified and classified tailings (cut at 125 µm). Application of the froth-fed CPF cell reduced the Cu grade in the +125 µm tailings to 0.031 % (vs. 0.052 % without the cell) and indicated potential for further reductions in overall plant tailings grade. Laboratory reference experiments were consistent with the pilot-scale findings. Classification improved froth stability and reduced mass yield, thereby doubling the coarse concentrate grade. These results indicate that froth-fed flotation is a technically and operationally feasible approach for enhancing coarse particle recovery, with the potential to provide a more compact, energy- and water-efficient solution for both scavenging and pre-concentration applications in base metal concentrators.