A hybrid flotation-gravity circuit for improved metal recovery

Abstract

The performance of a novel hybrid flotation-gravity concentration circuit was evaluated in which a Knelson Continuous Variable Discharge (CVD) separator was used as a scavenger for flotation tailings. Flotation tailings from the Eskay Creek Gold Mine were used for the study. Batch and pilot scale laboratory tests and plant trials were performed. Results of the batch and pilot tests showed that a product with a small yield (<5%), a high upgrade ratio and significant Au (sulphide mineral) recovery could be achieved. Plant trials confirmed the laboratory test results and hybrid flotation-gravity circuit in which CVD scavenging was followed by a regrinding-flotation process, could increase overall plant gold recoveries. In view of the results, there is also potential for improvements in metal recoveries for other sulphide mineral flotation systems. The paper describes how the results influence the selection of the target grind size and thereby impact grinding energy requirements, plant processing rate and could lead to further improvements in metal recovery by reducing flotation losses at the ultrafine particle size range. (C) 2010 Elsevier B.V. All rights reserved.