A Novel Process for Separation of Magnetite and Phosphorous Phases from a CaO–SiO₂–FeO–P₂O₅ Slag

Abstract

Iron and phosphorus were successfully separated from CaO–SiO₂–FeO–P₂O₅ slag through atmospheric control, B₂O₃ addition and a combination of magnetic separation and flotation. For the slag with basicity (CaO/SiO₂) of 2.5 and B₂O₃ addition of 6% (weight percentage), iron and phosphorus in the slag were enriched in the form of magnetite (Fe₃O₄) and calcium phosphate (Ca₁₀P₆O₂₅) phases respectively under Ar atmosphere. Using a combination of magnetic separation and flotation, the concentrates were obtained with Fe₃O₄ and P₂O₅ content of 92.84% and 37.66% respectively, corresponding to the recovery ratios of 85.8% for iron and 91.3% for phosphorus.