The depression mechanism of tara gum on the flotation separation of apatite from calcite: Experiments and molecular dynamics simulation

To address the challenges in selectively differentiating apatite from calcite via flotation, Tara gum (TG) functioned in the role of a calcite-selective inhibitor during this research. The micro-flotation tests indicated that apatite and calcite displayed comparable buoyancy characteristics when sodium oleate (NaOL) was utilized as the collector. Merely relying on NaOL alone made it extremely arduous to effectuate an efficient segregation of these two minerals. The addition of TG manifested potent and selective inhibitory effect on calcite floatability, while exerted no substantial influence on the flotation of apatite. The findings from the artificial mixed ore tests signified that employing TG in a suppressing role not only enhanced the P₂O₅ grade within apatite but also had a relatively minor effect on the recovery rate. Surface wettability tests demonstrated that under the combined influence of TG and NaOL, the disparity in hydrophobicity between apatite and calcite was further augmented. Zeta potential measurements intimated TG being present in the system did not impinge on the adsorption of NaOL on the surface of apatite but severely impeded its adsorption on the surface of calcite. Experimental findings from adsorption capacity tests revealed the adsorption quantity of TG on the surface of calcite exhibited a significantly elevated magnitude compared to that on the surface of apatite. X-ray photoelectron spectroscopy (XPS) measurements analysis corroborated that TG was adsorbed on the surface of apatite via weak interactions, while atop the calcite surface, it underwent robust chemisorption with Ca through hydroxyl groups. The outcomes of simulation calculations further substantiated that TG had a greater propensity to attach across the surface of calcite relative to apatite. Based on these experimental revelations, TG held the promise of serving functioning as a discriminatory suppressing agent for the flotation separation of apatite from calcite.