Pyrometallurgical Treatment of High Manganese Containing Deep Sea Nodules

The steadily growing demand for critical metals and their price increase on the world market makes the mining of marine mineral resources in the not too distant future probable. Therefore, a focus lays on the development of a sustainable, zero-waste process route to extract valuable metals from marine mineral resources such as manganese nodules. These nodules contain industrially important metals like nickel, copper and cobalt in substantial amounts. However, the development of a general metallurgical process route is challenging due to varying nodule compositions. Especially challenging is a high Mn content, since the liquidus temperature of a smelted slag phase directly correlates with Mn content. This paper presents thermodynamic models created in FactSage™ 6.4, which support direct reduction smelting of manganese nodules in an electric arc furnace. Thermodynamic modeling has never been applied to the metallurgical treatment of manganese nodules, and therefore, represents a significant advantage over previous studies. Furthermore, these calculations were verified in lab scale experiments. The nodules were supplied by BGR, German Federal Institute for Geosciences and Natural Resources, and have origin in the German licensed territory of the Clarion Clipperton Zone in the Pacific Ocean.