Reduction leaching of manganese nodules by nickel matte in hydrochloric acid solution

Abstract

A process for the reduction leaching of nodules from the Pacific Ocean using nickel matte in dilute hydrochloric acid solution was investigated. It has been proven that the nickel matte is an effective reductant for the leaching of manganese nodules; nearly 100% of the Mn can be easily leached in a 1.5–2.0 M hydrochloric acid solution at 95°C for 80 min. The concurrent extractions of Ni and Cu are more than 90%, and Co about 80%. The sulfur contained in the raw materials will mostly remain in the elemental state in the leaching residue.