Mitigating iron contamination in cyanide gold extraction: Ceramic grinding media for enhanced efficiency and reduced cyanide consumption

Mechanochemical interactions during regrinding can influence the surface properties of gold concentrates and the surrounding pulp chemistry. This study compares the effects of ceramic and chrome steel grinding media on gold cyanidation performance using chemical analysis, scanning electron microscopy with energy dispersive spectroscopy (SEM–EDS), X–ray photoelectron spectroscopy (XPS), and time–of–flight secondary ion mass spectrometry (ToF–SIMS). The results showed that ceramic grinding media generated finer particles with smoother surfaces and substantially lower iron contamination. Relative to chrome steel grinding media, ceramic grinding media increased the gold extraction from 93.3% to 95.0%, reduced sodium cyanide consumption by 10.7%, and decreased thiocyanate ion concentration by 6.5% after 24 h of leaching. Additionally, ceramic grinding media helped sustain higher dissolved oxygen levels throughout the leaching process. XPS and ToF–SIMS analyses revealed that ceramic grinding media suppressed the formation of FeOOH, FeO, and Fe–CN species on mineral surfaces, thereby improving cyanide accessibility to gold particles. These findings demonstrate that ceramic grinding media effectively regulate the interfacial chemical environment, enhancing both the efficiency and environmental sustainability of gold cyanidation.