Extraction of metal values from manganese nodules in the ocean environmentusing zinc matte as a reductant

The leaching process of manganese nodules in the marine environment is sign ificant in the recovery of several metal values. In this experiment, reduct ion leaching of manganese nodules was carried out using zinc matte as a red uctant in dilute HCl solution. The leaching characteristics of Mn, Co, Ni, and Cu from manganese nodules depended on the leaching temperature and init ial HCl concentration. A temperature of approximately 70 degreesC was suita ble for the present reduction leaching, and the extraction rate increased w ith increase in the initial HCl concentration. More than 97%, of Mn, 92% of Co, and 88% of Ni were easily extracted. The dissolution of Mn, Co, Ni, an d Cu depended upon the amount of zinc matte added. The ratio of liquid and solid was also an important factor in the extraction of manganese nodules. As the liquid/solid (L/S, lixiviant/manganese nodule) ratio was increased, the extraction rate increased. The extraction rate was independent of stirr ing speed.