The Demonstration of the Cuprion Process for Recovery of Nickel, Cobalt, Copper, and Manganese from Seabed Nodules

Abstract.

Dreisinger Consulting Inc. (DCI) has evaluated the application of the Cuprion process for processing of seabed nodules from the Clarion Clipperton Zone in the Pacific Ocean. A program of bench and pilot plant testing was conducted to demonstrate the reductive leaching of ground nodules in a seawater-based ammonia–ammonium carbonate leach solution. The batch leach testing confirmed that extraction of copper, nickel, and cobalt exceeded 90%, leaving a manganese carbonate residue for manganese recovery. The Cuprion leach process was piloted over a 5-day period in a series of continuous overflow reactors with closed loop solution recycle. Pilot metal extractions confirmed or exceeded the lab leach testwork results and led to increased understanding of the Cuprion process. The pilot plant solutions containing extracted metals were treated by oxidation and solvent extraction to demonstrate co-extraction of nickel and copper. The pilot plant residue contained manganese carbonate formed by the reductive leaching chemistry. This residue may be treated to extract and recovery manganese as EMM along with residual amounts of copper, nickel, and cobalt. The results of the batch and pilot testing are presented.