The selective flotation separation of rhodochrosite against quartz and calcite with dicarboxylic amino acid-based surfactants as a novel collector

• DPA is a promising selective flotation collector for rhodochrosite . • DPA can separate rhodochrosite from quartz and calcite without depressant. • DPA owns high selectivity because it has multiple active sites on mineral surfaces. • DPA can chemically adsorb on rhodochrosite surface. • DPA molecules formed two distinct adsorption geometries on rhodochrosite surfaces. Rhodochrosite is often associated with calcium- and silicon-bearing minerals, resulting in a low grade, and it is difficult to achieve efficient flotation separation with conventional collectors. A novel collector, 2-decanoylamino-pentanedioic acid (DPA), was synthesized by constructing an amide group and double-branched carboxylic acid molecular structure to selectively separate rhodochrosite against quartz and calcite. The flotation results demonstrated that, compared with sodium oleate, DPA exhibited superior collecting performance and enabled the separation of rhodochrosite from quartz and calcite under neutral pH, with no addition of a foaming agent or activator; thus, DPA is regarded as an appropriate flotation collector for rhodochrosite. Analysis of the contact angles, Fourier transform infrared spectroscopy (FTIR), zeta potential and X-ray photoelectron spectroscopy (XPS) results showed that DPA chemically adsorbed on the surface of rhodochrosite, forming 8-membered ring or two 4-membered ring structures. However, no significant interaction was detected on the surface of quartz and calcite, providing evidence for the flotation separation of rhodochrosite from calcite and quartz. This research provides a potential collector for efficient utilization of rhodochrosite.