Comparative evaluation of reagent-removal pretreatments for Cu-Mo separation of a bulk Cu-Mo concentrate

Abstract

Bulk flotation followed by selective Cu-Mo separation is widely used for porphyry copper-molybdenum ores, but collectors carried over from bulk flotation can hinder the subsequent depression of copper sulfides. In this study, roasting, oxidative treatment, and mechanical agitation were compared as reagent-removal pretreatments for an industrial bulk Cu-Mo concentrate from the Jiama deposit, Tibet, using laboratory-scale and expanded batch flotation tests. All three pretreatments affected Cu-Mo separation at laboratory scale, with roasting and H 2 O 2 treatment giving the more favorable responses. After scale-up, however, only roasting retained clear separation selectivity. FT-IR comparisons with reference compounds suggested that the collector-derived hydrophobic species formed on chalcopyrite exhibited copper butyl xanthate-like characteristics and that oxidative treatment generated oxygen-containing products; these spectra were used as qualitative supporting evidence. Under the selected roasting condition of 175 °C for 10 min, followed by one roughing and one cleaning stage, a molybdenum concentrate with a yield of 9.42%, a Mo grade of 5.59%, and a Mo recovery of 61.85% was obtained, while the corresponding Cu recovery was 7.47% at a Cu grade of 22.98%. Among the pretreatments examined, roasting provided the most robust separation response for the investigated industrial concentrate.