Abstract:Characteristics of magnetite reduction in copper smelting slag by biodiesel from waste cooking oil and petroleum diesel were studied. Distribution of high-temperature pyrolysis product from biodiesel and diesel was investigated to elaborate process of magnetite reduction in copper smelting slag by diesel and biodiesel. The results indicate that magnetite content drops while fayalite content rises after reduction. In process of copper smelting slag reduction, liquid reduction agents first crack into coke, H2, CO and CH4, et al, and fayalite phase is formed by combining SiO2 in copper molten slag and FeO reducted from magnetite by pyrolysis products. Reduction effect of magnetite with biodiesel is better than that of diesel due to production of more reducing gases through pyrolysis. It is feasible to substitute biodiesel to diesel as reductant in process of copper smelting slag reduction in electric furnace.