Investigation on the segregation roasting condition of manganese nodule

In order to find an economical system for recovering Cu, Ni, and Co from manganese nodules segregation, several conditions in calcination and segregation roasting were examined. Calcination is found necessary before segregation roasting because high water content of the nodule may cause the evolution of excess hydrogen which reduces metal oxides without passing through a series of segregation reactions. The best calcination temperature and time are 950°C and 30 min, respectively. Many factors affect the segregation results. Considering the reducibility and recovery of Ni, Cu, and Co, the following conditions would be suitable form of chloride: CaCl₂·2H₂O, CaCl₂·2H₂O addition: 26%, segregation roasting temperature: 900°C, segregation roasting time: 2 hr, coke addition: 14%, nodule size: 53-75μm, and coke size: 300-425μm. Under these conditions, 88%, 70%, and 56% recoveries of Cu, Ni, and Co were obtained.