IMPACT OF STEEL GRINDING MEDIA–INDUCED IRON CONTAMINATION ON FLOTATION PERFORMANCE OF VARIOUS ORES

Abstract: The influence of steel grinding media on flotation performance is strongly governed by iron contamination generated during wet milling. This study synthesizes experimental findings from six peer-reviewed investigations to evaluate how abrasion-, corrosion-, and precipitation-derived iron species alter pulp chemistry, mineral surface properties, and flotation responses across multiple ore types, including sulphide ores, scheelite, and PGM-bearing ores. Results demonstrate that steel grinding media significantly reduce pulp potentials (Eh) and dissolved oxygen (DO), promoting the formation of Fe²⁺/Fe³⁺ species and iron hydroxide coatings on mineral surfaces. SEM–EDS and XPS analyses consistently reveal extensive FeOOH and Fe(OH)₃ deposition, particularly on fine particle fractions, resulting in suppressed collector adsorption and decreased hydrophobicity. Comparative flotation data show that mild steel produces the lowest recoveries for chalcopyrite, scheelite, and PGM minerals, while ceramic and chromium-rich media substantially improve selectivity and overall recovery. Integrating these outcomes confirms that iron contamination is the dominant chemical mechanism reducing flotation efficiency in steel grinding environments, highlighting the need for optimized media selection to enhance metallurgical performance.