“Zero-Waste”: A Sustainable Approach on Pyrometallurgical Processing of Manganese Nodule Slags

Sommerfeld, Marcus; Friedmann, David; Kühn, Thomas; Friedrich, Bernd

doi:10.3390/min8120544

Cited by 34 publications

(28 citation statements)

References 10 publications

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“…The slag can further be treated to produce ferromanganese and silicomanganese for the steel industry and the metal alloy will then undergo hydrometallurgical processing to separate the metals. Finally, the generation of a compact, environmentally stable and toxin-free final slag, applicable to the construction industry, ensures an almost zero-waste processing route for the nodules 99 .…”

Section: Unique (Or Favourable) Characteristics Of Deep-ocean Miningmentioning

confidence: 99%

Deep-ocean polymetallic nodules as a resource for critical materials

Hein

Koschinsky

Kühn

2020

Nat Rev Earth Environ

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257

127

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Deep-ocean polymetallic nodules (also known as manganese nodules) are composed of iron and manganese oxides that accrete around a nucleus on the vast abyssal plains of the global ocean 1-6. Polymetallic nodules vary in diameter from less than one to tens of centi metres and acquire economically interesting quantities of critical metals (metals that are essential to the security and economic wellbeing of a nation) from ocean water and/or sediment pore waters. As a result, the enormous quantities of these nodules-which are conservatively estimated to total 21 billion dry tons in the Clarion-Clipperton Zone 7,8 (CCZ; located in the northeast equatorial Pacific Ocean) alone (Fig. 1)-host considerable tonnages of critical metals that are essential for green energy, vehicles and infrastructure, as well as for new technology and military applications. This reservoir of critical metals has, therefore, triggered interest in new deep-ocean mining operations. However, the potential environmental impacts of such activities are of great concern and have hastened extensive research and evaluation in this area 9-11. Polymetallic nodules were first discovered on the seabed at a depth of approximately 4,300-5,500 m during the 1872-1876 voyage of the HMS Challenger to study the deep ocean 12. A number of nodules, which contained numerous shark teeth and cetacean ear bones, were collected from the western end of the CCZ nodule field 12. Early hypotheses suggested that polymetallic nodules form by alteration of volcanic rocks and grains, especially glass, which are transformed into manganese carbonates and, finally, into oxides that are deposited from solution to form nodules on water-rich sediments 12-14. However, later work-aided in part by the 1957-1958 International Geophysical Year-revealed the general source of the metals (seawater and sediment pore water) and the sorption processes that might be involved in the acquisition of minor metals by nodules 15-20. Economic interest in the deep-ocean polymetallic nodules developed in the 1960s 15,16 , which subsequently led to the formation of consortia in Germany,

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Section: Unique (Or Favourable) Characteristics Of Deep-ocean Miningmentioning

confidence: 99%

Deep-ocean polymetallic nodules as a resource for critical materials

Hein

Koschinsky

Kühn

2020

Nat Rev Earth Environ

Self Cite

257

127

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“…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].…”

Section: Introductionmentioning

confidence: 99%

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

Deng

Chi

et al. 2020

Minerals

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Ocean manganese nodules, which contain abundant Cu, Co, Ni and Mn resources, were reduced using biomass (sawdust) pyrolysis technology. Valuable metals were further extracted by acid leaching after the reduction process with high efficiency. The effects of sawdust dosage, reduction temperature, and time were investigated to obtain optimal operating parameters. The extraction rates of Mn, Cu, Co, and Ni reached as high as 96.1%, 91.7%, 92.5%, and 94.4%, respectively. Results from TGA show that the main pyrolysis process of sawdust occurs at temperature range of 250–375 °C with a mass loss of 59%, releasing a large amount of volatile substances to reduce the ocean manganese nodules. The pyrolysis activation energy of sawdust was calculated to be 52.68 kJ∙mol−1 by the non-isothermal kinetic model. Additionally, the main reduction reaction behind the main sawdust pyrolysis process was identified by the comparison of the assumed and actual TG curve. The thermodynamic analysis showed that the high valence manganese minerals were gradually reduced to Mn2O3, Mn3O4, and MnO by CO generated from sawdust pyrolysis. The shrinking core model showed that the reduction process is controlled by the surface chemical reaction with activation energy of 45.5 kJ∙mol−1. The surface of reduced ore and acid leached residue exhibited a structure composed of relatively finer pores and rougher morphology than the raw ore.

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“…Therefore, the pyrometallurgical process has three main products: the FeNiCoCu alloy, which is further processed by hydrometallurgical treatment, ferromanganese, and the slag as a mineral byproduct. [4,6] The Institute of Mineral and Waste Processing, Waste Disposal and Geomechanics (IFAD) at the Clausthal University of Technology was assigned by the BGR to develop a concept of a hydrometallurgical process for the treatment of the FeNiCuCo alloy. Based on literature research and supporting experiments, the focus was to develop an economically feasible process.…”

Section: Introductionmentioning

confidence: 99%

Concept for a Hydrometallurgical Processing of a Copper‐Cobalt‐Nickel Alloy Made from Manganese Nodules

Keber

Brückner

Elwert

et al. 2020

Chemie Ingenieur Technik

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The processing of manganese nodules for the production of raw materials has been a subject of research for many decades. The nodules contain many valuable metals like copper, cobalt and nickel. In recent years, the German Federal Institute for Geoscience and Natural Resources developed a process for the processing of manganese nodules based on a combined pyro‐ and a hydrometallurgical route. Clausthal University of Technology was assigned to develop the hydrometallurgical process for the treatment of a FeNiCuCo alloy. The developed process consists of pressurized sulfuric acid leaching with the suppression of hydrogen gas formation, precipitation and solvent extraction.

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“Zero-Waste”: A Sustainable Approach on Pyrometallurgical Processing of Manganese Nodule Slags

Cited by 34 publications

References 10 publications

Deep-ocean polymetallic nodules as a resource for critical materials

Deep-ocean polymetallic nodules as a resource for critical materials

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

Concept for a Hydrometallurgical Processing of a Copper‐Cobalt‐Nickel Alloy Made from Manganese Nodules

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