Manganese Nodules in Chile, an Alternative for the Production of Co and Mn in the Future—A Review

Abstract

Given the active growth of emerging technology industries, it has become essential to have large quantities of critical metals to meet the current demand. In the Chilean mining industry, there is a depletion of high-grade mineral ores, and there is hence a need to increase production levels in the copper industry and diversify its market by extracting other elements. One of the strategies is to foster the production of lithium batteries, but the manufacture requires reserves of cobalt (Co) and manganese (Mn). Currently, Co reserves are not being exploited in Chile, and Mn production is almost negligible. This is due to the apparent shortage of high-grade ores on the land surface of the country. Given this scenario, the seabed manganese nodules are presented as a good alternative due to their high average grades of Co and Mn, which in turn would allow the growth of strategic value-added industries including lithium battery production. Chile’s current environmental regulations prevent the exploitation of marine resources. However, given technological advances worldwide, both in collection mechanisms and extractive processes, in addition to the needs generated from the future strategic plans, leads us to think about a project to exploit manganese nodules locally.

Characterization of Fines Produced by Degradation of Polymetallic Nodules from the Clarion–Clipperton Zone

“…With the development of various technologies for polymetallic nodule mining (see [39] for examples), some types of miners are now expected to entrain minimal amounts of sediment. However, based on our results, it is inferred that not only sediments around the nodules but also sediments "inside" the nodules will contribute significantly to the discharge.…”

The Reduction Behavior of Ocean Manganese Nodules by Pyrolysis Technology Using Sawdust as the Reductant

“…Their formation is the result of millions of years of mineral precipitation surrounding objects such as fish teeth, bones, etc. [7]. In addition, ocean manganese nodules are exploited two-dimensionally, reducing the costs in the mining process compared with three-dimensional 2 of 15 terrestrial deposits.…”

“…The extraction processes developed so far for ocean manganese modules can be mainly summarized by two categories: hydrometallurgy and pyro-hydrometallurgy processes [7,15,16]. Organic and inorganic reagents, such as HCHO, NH 3 OHCl, phenols, NO 2 , SO 2 , Na 2 SO 3 , H 2 O 2 , CH 3 OH, FeS 2 , coal, sucrose, glucose, lignite, sawdust, and nickel matte, are mainly used as reductants in different media to dissolve the targeted elements in hydrometallurgy process [17][18][19][20].…”

Manganese enrichment of polymetallic oceanic nodules via selective leaching process for energy storage applications

“…), there has been a recent surge to explore alternate sources for meeting the high demand for critical metals like Co, Ni, Cu, and Mn 1–3 . The earth's terrestrial resources are being continuously degraded, which has terrible implications, like the degradation of terrestrial copper deposits from 4% in the year 1900 to 0.5% in the recent years (with areas reaching as low as 0.26%), and the degradation of cobalt grades in Chile from 4%–5% in 1942 to current values as low as 1.6% 3,4 . Presently, the second largest importer of manganese ore is India.…”

“…Additionally, the hydrometallurgical route is more likely to be used for leaching of the manganese nodules because of their high‐water content capacity, which holds firmly even at high temperatures due to capillary condensation in extremely fine pores. This water content causes the pyrometallurgical stages to require high energy consumption, rendering it unsuitable 4 . The process includes separation and purification of high valued metal/materials from nodules, and it is mainly obtained through the aqueous route of acid/ammonia leaching, using various conventional/nonconventional reducing agents 11,16–17 .…”