Surface Chemistry and Activation of Pyrite in Flotation: Enhancing Critical Minerals Recovery

Pyrite (FeS₂), traditionally regarded as a gangue mineral, has emerged as a potential host for critical and precious elements such as tellurium (Te) and gold (Au), particularly within porphyry copper systems. This review critically evaluates the surface chemistry and activation mechanisms of pyrite in froth flotation, with the aim of improving its recovery from both primary ores and sulfide-rich tailings. Emphasis is placed on the electrochemical and structural factors governing pyrite floatability, including the influence of redox potential, pH, and the detrimental effects of surface oxidation and common depressants such as lime and cyanide. The roles of various chemical activators – copper sulfate, lead nitrate, sodium sulfide, and carbon dioxide – are examined in restoring pyrite surface reactivity and enhancing collector adsorption. By integrating surface activation strategies with selective reagent schemes, this study outlines promising approaches for the valorization of pyrite as a carrier of critical and precious metals, contributing to both enhanced metal recovery and sustainable tailings management.