Influences of electronic spin structures on the magnetic properties of Fe, Co and Ni ions and the adsorption of collectors

The electronic spin properties of Fe, Co and Ni metal ions in the octahedral field formed by S and O ligands were studied by density functional theory (DFT). It is found that in M-O octahedral field, the metal exhibits a high spin nature, whereas in M-S octahedral field, the metal exhibits a low spin nature. This suggests that O atom is a weak-field ligand and S atom is a strong-field ligand. It is found that M-O atoms are mainly ionicly bonded, whereas M-S atoms are mainly covalently bonded. This result is consistent with the M-O and M-S bonds in the real metal oxide and sulfide minerals. Hence, M-O and M-S coordination compound models can be used to simulate the crystals of the real oxide and sulfide minerals. Then the adsorption of O- and S-containing flotation collectors on these two mineral models was studied. It is indicated that S-containing collectors could not effectively collect oxide minerals, but O-containing collectors have strong collecting ability to oxide minerals. In addition, the collecting ability of S- and O-containing collectors to sulfide minerals is nearly the same. These are consistent with the flotation practice that O-containing collectors have no selective collecting capacity on oxide and sulfide minerals but S-containing collectors have strongly selectively collecting capacity to sulfide minerals.