Abstract: Manganese-leaching from a low-grade pyrolusite was investigated using cassava lees as reducing agent in sulfuric acid medium.Orthogonal and single-factor experiments were employed to examine the influences of concentrations of sulfuric acid,leaching temperature,reaction time,and amount of cassava lees on Mn leaching rates.Results showed that influencing order of the main factors on Mn leaching rate followed by sulfuric acid concentration,reaction temperature,leaching time,and amount of cassava lees.Suitable leaching conditions were obtained as 3.13 mol/L H₂SO₄ and 0.3 mass ratio of cassava lees to pyrolusite for 3 h at 90 ℃.Mn leaching rate under above conditions reached 94.8%.

Key words: pyrolusite, cassava lees, reductive leaching