In this study, a flotation collector N-(carboxymethyl)-N-tetradecylglycine (NCNT) was introduced for the purpose of energy-saving, and its adsorption ability on a fluorapatite (001) surface was investigated by density functional theory calculation. The results of frontier molecular orbital analysis of NCNT and adsorption energy between NCNT and fluorapatite (FAp) showed that NCNT possessed better activity and stronger interactions in the reagent–FAp system than oleic acid (OA). A simulation model revealed that the adsorption positions of NCNT on the fluorapatite surface are calcium atoms, at which NCNT chemisorbed on (001) fluorapatite surface via a bidentate geometry involving the formation of two Ca–O bonds. Flotation experiments verified that NCNT had a good recovery of 92.27% on FAp at pH 3.5, which was slightly lower than OA. Moreover, NCNT was used at 16 °C, which was much lower than the OA’s service condition (25 °C).

This study examined the appropriate hematite (Fe₂O₃) collector for the concentration of pyrolusite (MnO₂) in a reverse flotation. Actual ore flotation studies were performed to determine how sodium oleate, sodium dodecyl sulfonate, and oxidized paraffin soap affect hematite removal during reverse flotation of pyrolusite ore. In order to explore the flotation mechanism, simulation experiments were carried out. Firstly, the crystal models of pyrolusite and hematite were established. Then, in order to verify the reliability of the simulation results, the simulated XRD spectra of the crystal model were compared with the measured spectra. Finally, density functional theory and molecular dynamics modeling were used to study the interaction between collector molecules and mineral surfaces. The flotation test results show that oxidized paraffin soap is the best hematite collector and promotes its flotation, removing iron from pyrolusite. Molecular dynamics simulations and density functional theory show that the three collectors (oxidized paraffin soap, sodium oleate, and sodium dodecyl sulfonate) have a much stronger interaction with hematite than with pyrolusite. Therefore, it is possible to separate pyrolusite and hematite through flotation. The simulation results also show that oxidized paraffin soap has the highest adsorption strength and selectivity for hematite. This characteristic makes oxidized paraffin soap an excellent collector for effectively removing hematite from pyrolusite in the reverse flotation process.