Study on the surface modification and activation mechanism of lime-depressed pyrite by Cu(II) species

Abstract

Pyrite is frequently encountered in conjunction with other sulfide minerals and is commonly subjected to depression by lime during mineral processing, which aim to isolate and concentrate precious minerals. In light of the continuous exhaustion of Earth’s mineral wealth, the retrieval of pyrite that has been hindered by lime deposits has emerged as a pressing concern and a top priority. This study explored the use of Cu(II) to activate lime-depressed pyrite. Scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDS), time-of-flight secondary ion mass spectrometry (ToF-SIMS), X-ray photoelectron spectroscopy (XPS), ultraviolet–visible (UV–vis) spectrophotometers, and contact angle tests were utilized to reveal the activation mechanism of Cu(II) on lime-depressed pyrite. These techniques were employed to analyze surface morphology and characteristics, spectral characteristics, adsorption capacity for collectors, and surface hydrophobicity. The surface morphology and spectral characteristics analyze indicated that the addition of Cu(II) led to the dissolution of hydroxyl and sulfate species on lime-depressed surfaces, and results in the formation of new copper sulfide and Fe-O-Cu species. These newly generated copper species enhanced the adsorption capacity of collectors on the pyrite surfaces, thus improving the hydrophobicity of pyrite. After Cu(II) treatment, the lime-depressed pyrite exhibited improved recoverability through flotation, ultimately achieving a peak recovery of 81.50%.