The main purpose of this study was to demonstrate a novel, sustainable flotation process for the selective extraction of chalcopyrite from sulfide ores containing pyrite as the primary gangue mineral. This process is based on the partial replacement of fossil-based potassium amyl xanthate (PAX) collectors with bio-based, biodegradable, and non-toxic organosolv lignin particles (OLP). In the rougher stages, the addition of OLP increased copper recovery by almost 20 %, while improving selectivity; concentrate grades increased from 7.1 % to 12.2–12.4 %. In the cleaner stages, copper recovery (86.2–89.0 %) was approximately twice that achieved using PAX alone (41.9 %). Consequently, the proposed process enabled a 70–80 % reduction in PAX dosage while enhancing flotation performance. Furthermore, the total elimination of lime was possible, as the OLP maintained high selectivity even at a lower pH of 8.6. The results indicate that OLP modifies the flotation response of sulfide minerals, enhancing chalcopyrite recovery while suppressing pyrite flotation, likely through selective surface interactions and changes in surface charge under mildly alkaline conditions.
Hrůzová et al. (Wed,) studied this question.