Interaction behavior between coarse-particle pyrite and fine-particle pyrite in flotation

Abstract

Abstract Pyrite is commonly associated with gold deposits and serves as a gold-bearing mineral. The flotation recovery of gold-bearing pyrite generally determines the overall gold recovery. In this study, pyrite from a gold ore in southwestern Guizhou Province was selected to investigate the interaction behavior between coarse-particle pyrite (CPy) and fine-particle pyrite (FPy) during flotation. Flotation tests were conducted in combination with laser particle size analysis, optical microscopy, scanning electron microscopy (SEM), energy-dispersive spectrometry (EDS), and a self-assembled “Particle Attachment Dynamic Observation System.” The results showed that the recovery of FPy (P80 = 26.75 µm) was lower than that of CPy (P80 = 147.89 µm) under the same collector concentration (butyl xanthate). However, the flotation recovery of the CPy-FPy mixture was consistently higher than that of either CPy or FPy alone, particularly at low collector concentrations. Further investigation confirmed that CPy acted as a carrier for FPy, enhancing its recovery into the froth during mixed flotation. Calculations based on the extended Derjaguin–Landau–Verwey–Overbeek (EDLVO) model demonstrated that butyl xanthate increases hydrophobic forces between pyrite particles, promoting agglomeration. This finding explains why the flotation recovery of the CPy-FPy mixture in a butyl xanthate suspension exceeds that of CPy or FPy alone.