Fine and ultrafine flotation with the Concorde CellTM – A journey

Abstract

The Concorde Cell is a high-intensity pneumatic flotation cell dedicated to fines and ultrafines. Its development by Professor Graeme Jameson and later on by Metso was driven by two considerations: a reduction in bubble size and an increase in the shear rate and energy dissipation rate increases the particle–bubble collision and attachment efficiencies of fine particles. The Concorde Cell is a technology which produces fine air bubbles with high carrying capacity, thereby allowing increased capacity per unit; smaller footprint and a greater recovery of valuable fine particles which can be lost in other flotation cells. In addition, with a smaller number of flotation stages or less recycle required to achieve the desired recoveries, operational expenditures like power, water and reagents can be reduced.In this article, the potential of the Concorde Cell is explored through six cases, from base metals to metallurgical coal. Its main operating parameters, Air-to-Pulp Ratio, froth washing, froth depth and tailings recycle ratio, are investigated and show that the metallurgical performance of the Concorde Cell follows expectations based on the literature. Amongst others, higher APR leads to higher mass pulls and higher recoveries but lower grades, deeper froth depth increases selectivity… But the data also demonstrate the typical complexity of flotation, whereby the negative impact of increased APR can be compensated with froth washing to maintain high grades at high recoveries for example.About ten industrial scale flotation projects worldwide are deploying the Concorde CellTM. The examples of a metallurgical coal washing plant in Australia and of a copper plant in Zambia prove the capacity of the Concorde Cell to better recover the fines and ultrafines while providing high selectivity. In the two case studies, the Concorde Cell outperformed the previous technology specifically on the finest fractions of the processed streams.