Reverse flotation of iron ore by a new ternary collector-frother reagent: Applications through flotation experiments

Abstract

The reverse flotation of iron ore with etheramine collectors and starch as depressant is widely implemented industrially but has severe shortcomings in dealing with complex lithologies and reclamation of slimes and tailings. Previously, we explored the adsorption of a new ternary collector reagent based on a mixture of etheramine, amidoamine and a frother. FTIR band intensities point to favorable adsorption of reagent on quartz and kaolinite, lower on hematite and virtually null adsorption on goethite. Molecular dynamics simulation was also employed to reveal adsorption configurations and molecular orientations and density profiles. This paper aims to investigate the same ternary collector formulation for goethitic iron ore reverse flotation in absence of a depressant agent. Single minerals including quartz, kaolinite, hematite and goethite, and synthetic mixtures bench flotation kinetic experiments were performed, and kinetic flotation models were fitted to help rationalizing the results. The results indicate the new formulation as a more effective collector than the corresponding etheramine and amidoamine components under the studied conditions. The ternary collector allowed reaching high purity concentrates in hematite and goethite mixtures with quartz. A synthetic quaternary mixture also reproduced the performance of a real slimes sample, with even less iron loss to tailing due to particle size differences, which is a critical parameter for real slimes. Additionally, it is also suggested that goethite loss is driven by entrainment rather than true flotation, while hematite seems to be floated by both mechanisms. Quartz is well separated but kaolinite’s presence stems as the main shortcoming in these systems, since it is not well floated and also hinders the flotation of quartz. In cases of low content of kaolinite high purity concentrates were obtained, pointing the feasibility of a goethite desilication process without depressant.