A brief overview on manganese nodules processing signifying the detail in the Indian context highlighting the international scenario

Manganese nodules are the potential sources of base metals like copper, nickel, cobalt and manganese. Considerable research and development effort have been made all over the world to extract the metals from the manganese nodules during the past four decades. The paper summarizes the processes developed by various research and development organizations and metallurgical consortia for the extraction of metal values from the manganese nodules. Since copper, nickel and cobalt in the manganese nodules are in oxide forms and they are present in the lattices of iron and manganese minerals, these lattices are to be broken either by hydrometallurgical reduction or by reductive pyro-treatment for extraction of these metals. Based on this criterion, processing methods have been broadly divided into two categories: (i) pyrometallurgical treatment followed by hydrometallurgical processing and (ii) hydrometallurgical processing. Processes developed under these two categories have been discussed highlighting their merits and demerits. Pilot plant studies carried out by various metallurgical consortia like Kennecott Copper Corporation, Deep Sea Ventures, Metallurgical Hoboken Overpelt, and International Nickel Company are briefly described in this paper. The R&D efforts made in India in the processing of manganese nodules during last few decades are also discussed. (C) 2015 Elsevier B.V. All rights reserved.