Abstract
Pacific Ocean manganese nodules were leached in dilute sulfuric acid solutions using hydrogen peroxide as a reductant. High grade manganese nodules were crushed to minus 200 mesh, and treated to extract metals under the conditions, where pulp density was 1g/l, sulfuric acid concentration ranged from 3.5×10-3 to 3.5×10-2 mol/l, hydrogen peroxide concentration ranged from 1.7×10-3 to 2.6×10-2 mol/l, and temperature from 30 to 90°C. The results obtained are summarized as follows.
Nickel, cobalt, copper and manganese can be extracted quickly from manganese nodules by leaching in dilute sulfuric acid solutions in the presence of small amount of hydrogen peroxide at a room temperature. The extraction percentages of metallic components depended on both concentrations of sulfuric acid and hydrogen peroxide, and satisfactory extraction was not attained in case of shortage of either concentration of these reagents.
Different from ordinary leaching, the extraction percentages of metallic components decreased with elevating leaching temperature in this method. Under optimum conditions, the extraction percentages of nickel, cobalt, copper, manganese and iron were 100%, 95%, 100%, 100% and 60%, respectively.
