Synthesis and magnetic properties of manganese ferrite from low grade manganese ore

Manganese ferrite MnFe2O4 powders have been produced from low grade manganese ore after leaching of the ore in sulfuric acid and hydrogen peroxide. The produced solution was precipitated by using 5 M sodium hydroxide until pH 9-12 after correction Fe:Mn mole ratio to 2:1 using waste ferrous sulfate from iron and steelmaking. The produced precursors were thermally treated at temperature from 600 to 1200 degrees C. Effects of calcination temperature, calcination time and pH on the manganese ferrite phase formation and magnetic properties were studied. The results showed that a well-defined manganese ferrite crystal phase was formed when the calcination temperature increased to 1000-1200 degrees C. The maximum saturation magnetization (27.24 emu/g) was achieved at calcination temperature 1000 degrees C. calcination time 120 min and pH 10. (c) 2005 Elsevier B.V. All rights reserved.