Abstract: Marine polymetaUic nodules were mainly consisted of manganese and iron oxides. The experiments prove that it was feasible to extract manganese from nodules and enrich copper nickel cobalt oxides in the residues by the method of tri-phase oxidizing. The optimized parameters are: 240℃; 2 h; a ratio of the amount of substance of KOH/MnO₂ about 45; an air supply of 0．5m³·h^-1; a particle size of powders less than 200 mesh. The enriching ratio of Fe and Ni is nearer 100 % and those of Cu and Co are both more than 93 %. The metals which located in the matrix might accelerate the decomposing of potassium manganete; for the potassium manganete was soluble, this reaction also realized the seperation of manganese and other metals.