The comprehensive and harmless utilization of copper slag flotation tailing (CSFT) is the key to a wastefreeand sustainable copper industry. Here, the mineralogy and molybdenum micro-dissemination inCSFT were quantified and characterized, and the feasibility of the comprehensive recovery of Mo, Cuand Fe resources from CSFT and hazardous elements fractionation behavior by magnetic separationwas discussed. To investigate the occurrence and abundance of Mo in each phase, CSFT was classified intofour types of phases, including magnetite/hematite (27.26%), silicate associations (43.37%), and metallicsulphides and oxides. Molybdenum distribution is closely related to magnetite/hematite-Fe and S. Themagnetic separation results indicated that Mo and Cu were enhanced in magnetic products by 34–41and 15–21%, respectively. Cleaner non-magnetic residues were found to decrease significantly by 37–44, 58–60, and 11–19% for Cu, As, and Cr, respectively. Mineral fractionation was observed instead ofchemical changes during magnetic separation. Despite a weak separation effect on magnetic and nonmagneticphases due to their close bonds and fine-disseminated minerals, the Fe-silicate associationswithout magnetic phases were well separated into non-magnetic residues. The enrichment of Ca, Mgand separation of an iron-silicate component in non-magnetic residues enhanced the cementitious propertyand allowed the development of more pathways of reutilization.