Exploration of pullulan as a new environmentally friendly selective depressant of calcite in fluorite flotation separation

This study introduces a novel, environmentally friendly selective depressant for calcite, characterized by good solubility at low temperatures and low solution viscosity. Flotation experiments evaluated its depressant performance, revealing that pullulan selectively depresses calcite without compromising fluorite recovery.

The mechanism underlying this selective depression was investigated using contact angle measurements, adsorption capacity determination, zeta potential analysis, Fourier-transform infrared spectroscopy (FTIR), and density functional theory (DFT) calculations. The results demonstrate that pullulan selectively adsorbs onto the calcite surface, rendering it hydrophilic, while not interfering with the hydrophobic modification of fluorite by sodium oleate (NaOl).