Flotation separation of chalcopyrite from pyrite using baicalin as an organic depressant

During the separation process of pyrite and chalcopyrite, baicalin has an inhibitory effect on pyrite. • The adsorption amount of baicalin on pyrite is greater than that on chalcopyrite. • It elucidates the adsorption mechanism of baicalin on the surface of pyrite. • Baicalin adsorbed on pyrite and blocked subsequent collector adsorption on the mineral surface. In this study, baicalin (BA), a flavonoid compound, was used as a depressant for the selective separation of chalcopyrite and pyrite. The performance and mechanism of the depressant were comprehensively investigated. BA exhibited selective inhibition of pyrite during flotation separation. Under conditions of pH = 6, a BA dosage of 20 mg/L, a potassium butyl xanthate (KBX) dosage of 15 mg/L, and a MIBC dosage of 20 mg/L, the copper recovery rate in the concentrate reached 74.51%, with a grade of 33.707%. Contact angle and ToF-SIMS measurements showed that BA exhibited selective adsorption on the pyrite surface, thereby enhancing surface hydrophilicity. In contrast, the adsorption of BA on the chalcopyrite surface was found to be negligible. XPS and FTIR analyses further confirmed that the carboxyl or hydroxyl groups in baicalin exhibit strong adsorption at Fe sites on the surface of pyrite, whereas adsorption on the surface of chalcopyrite is weaker. Therefore, BA has the potential to serve as a depressant for the selective separation of chalcopyrite and pyrite. As a flavonoid, BA contains carboxyl (–COO) and hydroxyl (–OH) groups, which readily interact with active metal sites on the mineral surface. XPS results further confirm that the carboxyl (–COO) or hydroxyl (–OH) groups of BA interact with Fe ion sites on the surface of pyrite, while FTIR results further confirm that BA exhibits strong adsorption through the interaction of its hydroxyl (–OH) groups with Fe ion sites on the surface of pyrite. BA adsorbed on the pyrite surface occupies space and exerts electrostatic repulsion, thereby hindering the adsorption of KBX on the pyrite surface, thus achieving the selective flotation separation of pyrite and chalcopyrite. Based on the experimental results and mechanistic analysis, the adsorption of BA and KBX on pyrite and chalcopyrite was qualitatively simulated; Fig. 16 shows a schematic diagram of the qualitative adsorption of BA and KBX on pyrite and chalcopyrite. Download: Download high-res image (206KB) Download: Download full-size image