Yanling Xu

The concentration of inevitable ionic species in regenerated water significantly alters the flotation characteristics of rare earth minerals, thereby hindering the effective extraction of bastnaesite. Therefore, it is of great significance to study the influence and mechanism of inevitable ions on the flotation of bastnaesite. This paper systematically investigated the effects of Ca²⁺, Mg²⁺, and Fe³⁺ on the flotation behavior of bastnaesite using a BHA/OHA combined collector system and studied the mechanism of action using contact angle testing, Raman spectroscopy, and Visual MINTEQ solution chemistry calculations. The results showed that the BHA/OHA combined collector had good collecting performance for bastnaesite, while Ca²⁺, Mg²⁺, and Fe³⁺ all had varying degrees of inhibitory effects on its flotation, with the order of influence being Fe³⁺ > Mg²⁺ > Ca²⁺. Contact angle tests showed that the presence of inevitable ions weakened the effect of the combined collector on improving the hydrophobicity of the bastnaesite surface. Raman spectroscopy results indicated that inevitable ions interfered with the adsorption of the combined collector on the mineral surface, with Fe³⁺ having the most significant effect. Solution chemistry analysis further demonstrated that Ca²⁺ and Mg²⁺ have been the primary ions influencing flotation because of their interactions with the mineral surface and collector molecules, but not Fe³⁺, which is mainly adsorbed on the mineral surface in the form of hydrolyzed species, thereby inhibiting the reagent adsorption and enhancing the surface hydrophilicity. Based on this, this paper revealed the differentiated interference mechanisms of different inevitable ions on the flotation of bastnaesite, and applied the relevant insights to guide the recovery of rare earth resources in molybdenum tailings, providing a theoretical basis and new research ideas for the flotation control of bastnaesite and the efficient utilization of rare earth resources under complex backwater conditions.

Chalcopyrite and bornite are typical copper sulfide minerals; however, the interaction mechanisms between these minerals and conventional collectors—sodium butyl xanthate (BX) and ammonium dibutyl dithiophosphate (ADD)—when used in combination remain unclear. To address this issue, this study integrated flotation tests, FTIR spectroscopy, adsorption measurements, and AFM to investigate the effects of BX, ADD, and their mixture on the floatability of the two minerals. Flotation results showed that chalcopyrite exhibited excellent floatability in all collector systems, with above 90% recovery. Within the pH range of 3 to 11, BX outperformed ADD in enhancing bornite flotation. The BX/ADD mixture at a mass ratio of 3:1 had no significant effect on chalcopyrite recovery but significantly improved bornite recovery to 84.20% at pH 9. FTIR confirmed chemical adsorption of both collectors on the mineral surfaces. AFM further visualized stronger adsorption of BX on both chalcopyrite and bornite. Compared with single BX or ADD alone, the BX/ADD mixed collector exhibited more effective adsorption on chalcopyrite and bornite. The study provides guidance for reagent selection in the industrial flotation of chalcopyrite and bornite.