Separation and preparation of level I standard lead concentrate from lead ore via S-HGMS technology: description of separation mechanism

ABSTRACT To eliminate the adverse effects of traditional lead ore flotation methods, such as high reagent cost, complex operation process, and a large amount of wastewater, a superconducting high gradient magnetic separation (S-HGMS) technology was proposed to prepare level I standard lead concentrate (IGC) from lead ore. Under optimal conditions including a magnetic flow ratio of 0.076 T·s/m, a pulp concentration of 1.5%, a slurry flow velocity of 500 mL/min, and a 90% mass fraction of minus 45 μm, the Pb grade of the IGC product increased from 45.36% to 68.79% with 55.43% of Pb recovery, while all Cu, Zn, As, Fe, MgO, and Al2O3 concentrations of IGC decreased. The obtained IGC product meets the standard of level I in YS/T319–2013. The characterization results showed that lead ore comprised galena, sphalerite, and chalcopyrite. After S-HGMS, galena was effectively concentrated in the IGC product, while sphalerite and chalcopyrite were separated into the tailings. The magnetic field intensity and mineral magnetization characteristics were vital factors affecting the Pb grade and recovery of the IGC product. The S-HGMS technology efficiently achieved the preparation of the IGC product from lead ore, without using flotation agents and generating wastewater, and provides a valuable guideline for separating Cu – Pb, Zn – Pb, and Cu – Zn – Pb minerals.