Analysis of Industrial Flotation Circuits Using Top-of-froth and Concentrate Mineralogy

Abstract

ABSTRACT The aim of this work was to study the true flotation process and entrainment contamination along flotation banks. For this purpose, a new approach for characterizing the recovery and grade profiles down the industrial flotation banks was developed and tested in two industrial rougher banks, of nine 130 m3 and six 250 m3 cells. The procedure consisted of feed, top-of-froth (TOF) and concentrate grades measurement together with mineralogical analysis down the bank. These data are useful for the assessment of liberation and association of floatable particles recovered into the concentrate (true flotation) and gangue entrainment. Results allowed for the quantification of the decrease of Cu grade in concentrates and TOF samples along the banks, due to the relative increase of middling minerals and gangue entrainment. The liberation coefficient of Cu sulfides significantly decreased down the banks, because of preferential flotation of middling particles after exhaustion of the free Cu sulfide minerals. The main difference between concentrate and TOF samples was the entrainment content, while the composition of floatable minerals was similar. Therefore, the TOF measurement and mineralogical analysis provides a simpler way to assess the flotation process down the industrial flotation banks. This knowledge is relevant for process diagnosis and for selecting control strategies for flotation banks operation and optimization (e.g., froth depth and gas flowrates profiles).