An Innovative Sensor-Based Approach for Evaluating Performance of Flotation Circuit at the Expansion of Toromocho Copper Mine

Abstract

Chinalco’s Toromocho mine, located in the Morococha district of Peru, treated 117,200 mtpd ores during last 10 years. It is currently undergoing expansion, treating approximately 52,740 mtpd of chalcopyrite ore since 2021. As with the commissioning of most large plants, the metallurgical performance levels produced after stability was achieved were below the design criteria; more specifically, the Cu overall recoveries were 80–82% compared with the design value of 85%, and the final concentrate Cu grades were 20–23% compared with the design value of 24% over the past 2 years. It is clear that the copper losses in the fine size fraction (<10 µm) were due to unoptimized hydrodynamics. To overcome this obstacle and improve overall performance, an innovative approach for flotation circuit evaluation was designed and set up, to improve understanding of the nature of the mineral losses, benchmark the cell hydrodynamics as a platform to improve flotation cell operation, and link the circuit setup and operation to gas dispersion characteristics. These needs were fulfilled by the developments in gas dispersion sensor technology and process measurement methodology of CRIST. Effectively utilizing the sensor technology, it was observed that the deficient recovery of the Toromocho expansion plant was due to poor recovery of <10 μm Cu, as a result of a lack of small bubbles (<1 mm) compared to the pilot circuit. The resulting data highlight the potential for recovery improvement (increased kinetics) via bubble size reduction and increased air rate.