Abstract
The recovery of ultrafine sulfide minerals from flotation tailings remains a major challenge in mineral processing. Hydrophobic flocculation is an effective approach for improving the beneficiation of finely disseminated ores and technogenic tailings, with its efficiency strongly influenced by the reagent's hydrophilic-lipophilic balance (HLB). This study investigates a polyethyleneimine-sodium butyl xanthate (PEI-SBX) polycomplex as a hydrophobic flocculant-collector for the aggregation and flotation of ultrafine sulfide minerals. The HLB was calculated using the Griffin method, the structure was confirmed by FTIR spectroscopy, and performance was evaluated through sedimentation and flotation tests. Increasing the PEI ratio from 1:0.5 to 1:5 increased the HLB from 8.22 to 10.06, providing an optimal balance between reagent solubility and hydrophobic interaction with sulfide surfaces. At pH 8.5, sedimentation tests showed rapid aggregation of ultrafine chalcopyrite, galena, pyrite and sphalerite, with complete settling within 350–400 s. Microflotation of reground copper-lead-zinc tailings demonstrated increased metal recovery into the bulk concentrate by 6.88% for Cu, 4.05% for Pb and 4.73% for Zn. These findings demonstrate that HLB-controlled PEI-SBX polycomplexes promote hydrophobic floc formation and enhance the recovery of ultrafine sulfide minerals from technogenic tailings.