Enhanced process route to produce magnetite pellet feed from copper tailing

Abstract

The majority of copper mines generate a large quantity of tailings after their concentration processing. The flotation tailings are, in general, either piled up or stored in dams, although most copper tailings have a huge potential for by-products production leading to improve sustainability and profitability of operations. This paper describes a study aiming at producing a by-product magnetite pellet feed from IOCG (Iron oxide copper–gold) industrial copper processing tailings, located in northern Brazil. The mineralogy of copper tailings indicates around 14% of magnetite in its head composition, making its concentration of economic interest also allowing a considerable reduction in the amount of tailing disposal. The proposed route of this study is composed of hydrocyclones, low and high fields magnetic separation followed by silicates reverse cationic flotation. The complex mineralogy of IOCG deposits leads to the need for regrinding the rougher magnetite pellet feed to a P80 of 20 µm to achieve the desirable magnetite liberation. A saleable magnetite pellet feed within a high chemical quality (Fe > 64.1 wt%, SiO2 < 2.5 wt%, and Al2O3 < 2.0 wt%) and specific surface area of 2600 cm2/g was obtained. The results have shown a total mass recovery of 9.5% and 63% of magnetite recovery. Moreover, it was generated a non-magnetic rougher tailing with low magnetite and high quartz contents that might be used as a by-product as aggregated material in the construction industry and as soil remineralizer. An investigative flotation optimization is being undertaken and will be further published as a continuation of the present work.