New insights into the effect of differences in copper sites on the selective separation of CuFeS2 and MoS2 in Cu2+-containing systems

Copper site differences determine CuFeS 2 –MoS 2 flotation selectivity in Cu 2+ -containing systems. • ADT forms chelate coordination with surface Cu sites but not lattice Cu sites. • Monodentate ligands provide better CuFeS 2 –MoS 2 separation than bidentate ligands in Cu 2+ -containing systems. Interfaces involving Cu 2+ solutions play a critical role in CuFeS 2 -MoS 2 separation, and the differences among copper sites at the atomic scale are essential for understanding and controlling their separation in Cu 2+ -containing systems. Herein, sodium thioglycolate (STC) and amidinothiourea (ADT) were selected to systematically investigate the effects of copper site differences and inhibitor coordination modes on the selective separation of CuFeS 2 and MoS 2 in Cu 2+ -containing systems. The results suggest that the copper sites within the crystal lattice may be unable to form chelate rings with ADT, possibly due to geometric constraints imposed by the lattice coordination environment. In contrast, coordinated copper sites on the surface of CuFeS 2 may form chelate rings with ADT, thereby enhancing the inhibitory effect. The coordinated copper sites on the surface of MoS 2 may also exhibit a strong affinity for ADT, which hinders the selective separation of CuFeS 2 and MoS 2 . In comparison, STC exhibited a relatively weaker inhibitory effect on MoS 2 . Therefore, selecting reagents with appropriate structures may mitigate the adverse effects of Cu 2+ to some extent. These results suggest that monodentate ligand-based inhibitors containing multiple polar functional groups could be promising candidates for CuFeS 2 -MoS 2 separation in Cu 2+ systems. In addition, since Cu 2+ adsorbs more strongly to the surface of CuFeS 2 than to MoS 2 , and in combination with the control of Cu 2+ concentration, it is expected that the interference from Cu 2+ can be further reduced. This study provides new insights into the selection and design of MoS 2 -CuFeS 2 separation inhibitors in Cu 2+ -containing systems. Download: Download high-res image (300KB) Download: Download full-size image