The flotation chemistry between pyrite and isomeric xanthates (butyl xanthate and isobutyl xanthate) was investigated by means of adsorption experiments, surface tension tests, and molecular dynamic simulations in this work. The flotation chemical results were confirmed and further interpreted by quantum chemical calculations. The experiment results demonstrated that the isobutyl xanthate exhibited superior adsorption capacity and surface activity than those of butyl xanthate in flotation chemistry. In addition, molecular dynamic simulations were simultaneously performed in constant number, constant volume and temperature (NVT), and constant number, constant volume, and pressure (NPT) ensemble, indicating that the NPT ensemble was more suitable to the flotation system and the isobutyl xanthate was easier to be adsorbed on pyrite surface compared with butyl xanthate during an appropriate range of concentrations. Furthermore, the quantum chemical calculations elucidated that the isobutyl xanthate presented higher reactivity than that of the corresponding butyl xanthate based on the frontier molecular orbital theory of chemical reactivity, which was consistent with experimental and simulation results obtained. This work can provide theoretical guidance for an in-depth study of the flotation chemistry of pyrite with isomeric xanthates.

Characterization of modified humic substances based binders for iron ore agglomeration was examined by chemical analysis, optical density, Fourier transform infrared spectrum (FTIR), and thermogravimetry and differential scanning calorimetry (TG–DSC). Chemical analysis displays the proportion of fulvic acid (FA) to humic acid (HA) in the binder is 1:10. Compared with the HA, the FA possesses more functional groups. Meantime, optical density ratio analysis shows that the molecular weight and aromatization degree of the FA are smaller than those of the HA. FTIR spectra further confirm aromatic and aliphatic fractions are associated with various types of oxygen-rich groups including carboxyl and hydroxyl groups. TG–DSC and chemical analysis indicate structural changes of the binder including thermal decomposition, dehydroxylation and/or decarboxylation are caused during heating. The structural characterization of the binder ensures its good performance in the field of iron ore agglomeration.