Abstract:Physical and chemical properties of ocean polymetallic nodules from contract area were analyzed to understand its basic features. The results indicate that ocean polymetallic nodules have various external structures with particle size of between 1-100 mm, 90% of which are smaller than 50mm, and most of them are concentrated between 10-50 mm. Content of Mn, Fe, Ni, Co and Cu is 23.84%, 5.80%, 1.04%, 0.17% and 0.87% respectively. Content of silicon and aluminum is relatively high, and moisture content is as high as 22%. Average bulk specific gravity is 1.04 g/cm3 and average true specific gravity is 3.25 g/cm3. Crystallization degree is relatively good. Most manganese occurrence is in form of 10? aqueous manganese ore, and a small amount of lithic minerals are quartz and feldspar. Addition of CaF2 has obvious effects on reducing melting point temperature of sample, making phase transition move towards low temperature direction. Selective reduction separation and enrichment of nickel, cobalt, copper, iron and manganese are well realized by reduction roasting-wet magnetic separation process.