Ocean Manganese Nodules Research Articles

Investigation of the adsorption performance and mechanism of multi-source mineral composite calcination materials on heavy metal ions

To address the challenges of plume generation and the release of heavy metal ions caused by deep-sea mining operations, this study utilized multi-source minerals, including steel slag (SS), oceanic manganese nodules (OMN), attapulgite (AT), and sawdust (SD), to fabricate a multi-source mineral composite calcination material (MMCCM) through a sintering process, and then the preliminary heavy metal ion adsorption experiment was carried out. The results indicated that both Langmuir and Freundlich models can describe the adsorption behavior of Cu2+ in a single system, while the Freundlich model was more applicable in competitive systems. The adsorption of Co2+ and Ni2+ consistently aligned with the Langmuir model across all systems. The adsorptive behavior conformed to pseudo-second-order kinetics, indicating that chemisorption played a leading role. The intraparticle diffusion was the principal rate-limiting step, and the adsorption process was spontaneous. BET, TG-DTG, SEM-EDS, XRD, FT-IR and XPS elucidated that surface physical adsorption, ion exchange, complexation with functional groups, electrostatic attraction, and co-precipitation, which were the predominant adsorption mechanisms for MMCCM. Evaluations of regenerability, economy, security, and suitability demonstrated that MMCCM is an eco-friendly adsorbent, which provides materials and data support for future heavy metal marine sewage treatment, especially for immobilizing heavy metal in deep-sea sediments.

Adsorption of metal ions by oceanic manganese nodule and deep-sea sediment: Behaviour, mechanism and evaluation

Deep-sea mining disturbs the sediment on the seabed to form plumose flows, carrying metal ions that are transmitted through the food chain, posing a serious threat to marine ecosystems and human health. In this study, two types of marine raw materials were screened: Oceanic Manganese Nodules (OMN) and Deep-sea Sediments (DSS), and prepared the spherical regenerative adsorption materials OMN@SA, DSS@SA and OMN&DSS@SA using sodium alginate (SA) by sol-gel method. Preliminary investigations on the adsorption effect of metal ions were carried out. OMN@SA exhibited the best adsorption capacity, with the adsorption quantities for Cu2+, Co2+ and Ni2+ reaching 31.12, 21.11 and 16.66 mg/g, respectively. The adsorption behaviour is consistent with the Langmuir, pseudo-second-order kinetics and particle diffusion model, indicating that the adsorption process is mainly spontaneous, monolayer chemical adsorption, and the adsorption rate is mainly controlled by internal particle diffusion. SEM-EDS, XRD, FTIR and XPS analyses suggest that the adsorption mechanism includes surface physical adsorption, ion exchange, functional group complexation, electrostatic attraction and precipitation. The fixed bed column experiment shows that OMN@SA can effectively remove metal ions Cu2+, demonstrating excellent stability, safety and good regenerability. This study paves a new direction for the design of efficient and sustainable materials for heavy metal adsorption. More importantly, as marine primordial materials, OMN and DSS have strong technical and economic feasibility for future use in in-situ fixation of metal ions in seafloor sediments and restoration of the original seabed environment.

Extraction of various valuable elements from oceanic manganese nodules using coal gasification slag via reduction roasting-acid leaching process

In line with the concept of coal gasification slag treatment and marine mineral exploitation, this research proposed a residual carbon roasting-acid leaching process to extract various valuable metals from oceanic manganese nodules. The residual carbon obtained from coal gasification coarse slag was enriched via gravity separation without chemical treatment, and this carbon-high product served as an inexpensive reducing agent. The feasibility of carbon-high reduction of oceanic manganese nodules was explored using a thermogravimetric-mass spectrometric coupling system and thermodynamic analysis. The influence of mass ratio, roasting time, and roasting temperature on the reduction effect of oceanic manganese nodules was examined, and optimal conditions were determined through orthogonal tests. The results demonstrated that under the optimized conditions, the leaching rate of Mn exceeded 98%, and that of Cu, Co, and Ni exceeded 96%. The reduction and leaching processes were elucidated at the crystal scale through various ways. Finally, a comprehensive process flow diagram was summarized for the extraction of various valuable metals from oceanic manganese nodules using the residual carbon roasting-acid leaching process. This research will pave the way for the design of cost-effective and sustainable roasting reductants and reduction roasting processes for manganese oxide ores, contributing to economic and environmental benefits.

Bioleaching of oceanic manganese nodules: Current progress and future prospects

AbstractThe extraction of manganese elements and other strategic elements from oceanic manganese nodules has become a strategic decision to ensure the security of global metal resources and the high‐quality green development of metal resource processing and metallurgy industry due to the gradual depletion of high‐quality terrestrial metal resources and the increase of difficult‐to‐select and difficult‐to‐smelt deposits. In order to achieve the enrichment and separation of diverse elements within oceanic manganese nodules, it is imperative to initiate chemical reactions that facilitate the breakdown of complex oxides, particularly manganese dioxide. Bioleaching is a viable treatment option for oceanic manganese nodules with low operating costs and environmental damage. However, the mechanism of oceanic manganese nodules bioleaching is not fully studied, and the prospect of technology development is uncertain. We have reviewed five influencing factors on bioleaching of oceanic manganese nodules: mineralogical characteristics, chemical reaction equilibrium, thermodynamic characteristics, microbial properties, and operational variables. It then makes new development recommendations and technological system suggestions for the future improvement of oceanic manganese nodule bioleaching, primarily focusing on the development of new technologies for challenging to select and difficult to smelt ores, the practicality of strategic energy metal development, the cell design and its materials revolution, environmental protection and management, and all‐round resource utilization. Solving the above critical technical issues will boost the high‐quality development of metal industry and environmental protection.

A Sustainable Low-Temperature Roasting and Water Leaching Process for Simultaneously Extracting Mn, Cu, Co, and Ni from Ocean Manganese Nodules

A Sustainable Low-Temperature Roasting and Water Leaching Process for Simultaneously Extracting Mn, Cu, Co, and Ni from Ocean Manganese Nodules

The effect of Fe3+ ions on the electrochemical behaviour of ocean manganese nodule reduction leaching in sulphuric acid solution.

The effect of Fe3+ ions on the ocean manganese nodule reductive leaching in imitated sulphuric acid solutions was investigated. This work is presented in two courses, including the influence of Fe3+ ions on valuable metal extraction and the electrochemical reductive dissolution of manganese nodules. The results show that the beneficial effects of Fe3+ ion can be interpreted based on two aspects: the first is the acceleration caused by the active transformation of Fe3+/Fe2+ pair, and the second is the hydrogen ion buffer action generated by Fe3+ ion hydrolysis on the surface. On one side, Fe3+ ion could lessen the hydrogen consumption happening at the interface layer of the nodule supported by the leaching test and cyclic voltammetry results. On the other side, Fe3+ ions could be converted into Fe2+ ions and then preferentially reduce manganese oxide leading to an acceleration of the charge transfer reaction of the manganese nodule based on cyclic voltammetry, polarization, and impedance analysis results. The reduction leaching of manganese nodules in sulphuric acid solution is mainly controlled by the electrochemical interface reduction corresponding to manganese oxide dissolution, and the active conversion of the Fe3+/Fe2+ couple affects the dissolution of high valence manganese oxide.

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

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.

Mineralogická charakteristika fosforitové konkrece s rodochrozitem z lokality Tabarky, severní Chřiby

The second occurrence of phosphorite in the Chřiby Mts. was found in a secondary position (pebble from stream gravel) in the northern part of the mountain massif at the Tabarky site. Its original host rock environment were Cretaceous-to-Palaeocene flysch sediments of the Soláň Formation, belonging to the Rača Unit of the flysch belt of the Outer Western Carpathians. Based on bulk chemical composition, the studied phosphorite concretion is formed by ca. 47 wt. % of carbonate-fluorapatite, 31 wt. % of carbonate (rhodochrosite to Fe-rich rhodochrosite), and 21 wt. % of detritic admixture. The grains of carbonate are zoned with increasing Fe/Mn ratio from core to rim. Accessory pyrite with elevated contents (0.X wt. %) of Mn, Ni, Co, Cu, As and Pb as well as very rare sphalerite were also found. Phosphorite is product of early diagenetic processes operating in unconsolidated host deep-sea sediments. The material source of this mineralization was in unstable components of host sediments, which were remobilized by pore fluids under reducing conditions associated with shallow burial. The geochemical signature suggests that material resembling oceanic manganese nodules could have participate during formation of the studied authigenic mineralization.

The catalytic effect of AQDS as an electron shuttle on Mn(II) oxidation to birnessite on ferrihydrite at circumneutral pH

Abstract Birnessite (δ-MnO2) is the most common manganese (Mn) oxide mineral in soils, sediments, and ocean manganese nodules, and it significantly affects the speciation and mobility of trace metals and organic pollutants. Abiotic oxidation of Mn(II) by dissolved O2 is an important birnessite formation pathway, however, it has rarely been reported at neutral pH due to its very slow oxidation kinetics. Anthraquinone-2, 6-disulfonate (AQDS) is an important electron shuttle in biotic systems and might induce birnessite formation by promoting abiotic Mn(II) oxidation. Herein, the effects of AQDS concentration and types of mineral surfaces on 24 mM Mn(II) oxidation were explored at pH 7.0 using macroscopic and spectroscopic analyses. In the absence of AQDS, birnessite cannot form through the abiotic oxidation of 24 mM Mn(II) unless pH ≥ 8.5. In contrast, birnessite rapidly forms at pH 7.0 in the presence of AQDS, which acts as a catalyst. The catalytic effect of AQDS first increases and then decreases with increasing concentration, and as a “shuttle”, the concentration almost remains constant during Mn(II) oxidation. Additionally, in the absence of ferrihydrite or in the presence of montmorillonite, which is an analogous insulating mineral, AQDS shows a weak catalytic effect on Mn(II) oxidation; thus, no birnessite forms. The mechanisms of Mn(II) oxidation promoted by AQDS and ferrihydrite can be described as AQDS acting as an electronic carrier with semiconductor ferrihydrite as a specific channel facilitating electron transfer between Mn(II) and O2 on its surface. This study provides new evidence that AQDS can transfer electrons in abiotic systems as in biotic systems, leading to efficient Mn(II) oxidation and birnessite formation through an abiotic pathway at circumneutral pH in various geological settings.

Bioleaching of Indian Ocean nodules with in situ iron precipitation by anaerobic Mn reducing consortia

In the present study selective iron-free extraction of Cu, Ni, Co and Mn from Indian Ocean manganese nodules by manganese reducing consortium is described. The consortium isolated from manganese ore mines of Joda, Odisha (India) and enriched with Indian Ocean manganese nodules was used for bioleaching under facultative anaerobic conditions in mineral salt media using organic carbon source. Bioleaching was carried out at 30°C without agitation. Recoveries of Mn, Ni and Co increased with time, while maximum Cu recovery occurred during the initial period followed by a decrease. A notable finding was that Fe dissolution remained extremely low, i.e. less than 42mgL−1 (3.0%), possibly due to in situ precipitation of iron. X-ray diffraction patterns of bioleach residues indicated formation of FePO4 and MnCO3 phases. Iron dissolution remained consistently low even with increasing pulp density and decreasing particle size. The Mn reducing consortia may thus help in selective leaching of Mn while preventing Fe from contaminating the leach liquor, which is desirable in downstream processing of metal production from Mn-nodule and ferromanganese ores.

Application of manganese nodules leaching residue for adsorption of nickel(II) ions from aqueous solution

Deep ocean manganese nodules are significant futuristic resource of copper, nickel and cobalt. After recovery of these valuable metals, a huge quantity of residue (~70 % of ore body) is generated. In the present paper, investigations carried out for the application of washed manganese nodule leaching residue (wMNR) for the removal of nickel (Ni) ions from aqueous solution by adsorption are described. Several parameters have been varied to study the feasibility of using wMNR as potential adsorbent for remediation of Ni(II)-contaminated water. The adsorption kinetics followed pseudo-first-order equation, and the rate of adsorption increased with solution temperature. Kinetics data of Ni(II) adsorption were also discussed using diffusion models of Webber–Morris and Dumwald–Wagner models. The equilibrium data were best fitted into Langmuir adsorption isotherm, and the maximum adsorption capacity was found to be 15.15 mg g−1 at pH 5.5 and temperature 303 K, which decreased to 10.64 mg g−1 upon raising the solution temperature to 323 K. The activation energy for Ni(II) adsorption onto wMNR was 9.56 kJ mol−1 indicated physical sorption. Desorption studies showed successful regeneration of adsorbent and recovery of Ni. This process can be utilized for removal and recovery of Ni from the industrial effluent.

Recovery of manganese and nickel from polymetallic manganese nodule using commercial extractants

The paper describes a process for the recovery of manganese and nickel from the sulfuric acid leach liquor of Indian Ocean manganese nodules using starch as the reductant. The leach liquor contained 22.85g/L manganese, 6.38g/L iron, 1.01g/L copper, 0.023g/L zinc, 0.09g/L cobalt and 1.44g/L nickel. From this leach liquor, Fe was first precipitated out with Ca(OH)2 at pH3.8 followed by the extraction of copper using LIX 84I. From the almost Fe- and Cu-free leach liquor, Zn was extracted out as an impurity with D2EHPA in kerosene, after which the extraction of Mn was carried out with NaD2EHPA. The extraction efficiency of manganese using NaD2EHPA was 99.93% in 2-stages at A:O ratio of 3:4. The co-extraction of cobalt with manganese was 43mg/L which was subsequently removed by scrubbing in two stages with MnSO4 solution. The stripping of manganese was achieved with 4% H2SO4 in 2-stages at A:O ratio of 1:1. After extraction of Mn, Ni was extracted with NaD2EHPA. The extraction isotherm of nickel reads 2-stages at A:O ratio of 3:2. The co-extraction of cobalt with nickel was 47mg/L for which the Ni-LO was scrubbed out with NiSO4 solution. The stripping efficiency of nickel was 99.93% with 0.5% H2SO4 in 2-stages at A:O ratio of 1:1.

Application of ocean manganese nodules for the adsorption of potassium ions from seawater

Extracting potassium from seawater has great economic potential, although conventional methods offer low separation capacity and selectivity. In this study, a series of novel potassium ionic sieves (PISs) were synthesized using ocean manganese nodules (OMN) as raw materials. The PISs were characterized by XRD, SEM, and nitrogen adsorption–desorption. The potassium adsorption capacities and separation factors of PISs and OMN in KCl solution and sea brine showed that KMnO4 treatment will result in the highest adsorption and separation performance. The resulted sample OMN-C exhibit major composition of birnessite-type potassium manganese oxides and high micropore volumes. The adsorption capacities of OMN-C to K+ in KCl solution and sea brine were 35.2mgg−1 and 22.1mgg−1, respectively. The separation factor of OMN-C was α(K+/Na+)=108.6 and the sieve did not adsorb Mg2+, indicating its relatively high separation selectivity to K+. Therefore, OMN-C can selectively extract potassium from sea brine effectively. This study not only utilized the abundant OMN resources, but also prepared effective PISs, which showed great potential in the utilization of seawater.

Optimized Flowing Charateristics for Effective Lifting of Deep Ocean Manganese Nodules

Optimized Flowing Charateristics for Effective Lifting of Deep Ocean Manganese Nodules

Manganese precipitation kinetics and cobalt adsorption on MnO2 from the ammoniacal ammonium sulfate leach liquor of Indian Ocean manganese nodule

Precipitation of manganese from the SO2-roast leach ammoniacal ammonium sulfate solution bearing both high and low concentrations of manganese in the presence of copper, cobalt and nickel ions was carried out in a stainless steel reactor fitted with a turbo grid. Air/O2 was used to precipitate Mn as MnO2 from the solution. There was adsorption loss of cobalt from the solution. Precipitation of manganese from the solution was 57.2–99.9%. The maximum adsorption loss of Co was 22.1%. The precipitation of Mn and adsorption loss of cobalt from the solution followed the first order kinetics. The rate constants for the precipitation of manganese and loss of cobalt were evaluated and the experimental data were fitted to Freundlich and Langmuir adsorption isotherms.

Ocean manganese nodules as stromatolite with a fractal like-signature

Deep-sea manganese (Mn) nodules are problematic in terms of factors such as their characteristic form and genesis. There are many reports of bacterial species from manganese nodules. However, the genesis of these nodules has not been fully confirmed. Samples, mainly from the Clarion Clipperton Fracture zone in the Pacific Ocean, were examined by mineralogical methods and X-ray CT. Thin sections of these samples showed columnar stromatolite structures with rhythmic bands. Mineralized bacteria were observed by SEM and TEM. Surface morphology could be described as having a fractal-like nature. The fractal characteristics of spherical to dome-like forms were fundamentally composed of at least four ranks. The 4th order form corresponds to the stromatolite dome top shapes. Similar granular domain units and porous characteristics in manganese nodules were clearly observed by X-ray CT sections. Mathematical simulation based on fractal models reproduced similar morphological characteristics to the natural samples. So, we arrived at the concluding hypothesis that manganese nodules are aggregated stromatolite with fractal-like characteristics. Furthermore, we discussed the possibility that the nature of the layer manganese oxide minerals as the major component of the nodule and associated Fe-oxyhydroxide minerals may become an absorber/scavenger of strategic heavy metals and also toxic metals in the environments.

Sulphuric acid leaching of low/medium grade managanese ores using a novel nitrogeneous reductant-NH3NH2HSO4

Low and medium grade land as well sea based manganese ores were used for manganese extraction in H2SO4 - NH3NH2HSO4 (hydrazine sulphate) medium For land based Mn ores, only Mn recovery is important but for sea nodules which contain substantial amounts Co, Ni, and Cu, their recovery is equally important. In the present studies four samples used were: Indian ocean manganese nodules, medium and low grade Mn ores of Gujarat, and low grade Mn ore of Orissa, India. The Mn content of these ores varied from 15 to 39%. The objective of this work is to establish a reductant which can be used for leaching Mn from all types of ores. The optimum conditions established for nodules by varying parameters such as time, temperature, pulp density, H2SO4 and NH3NH2HSO4 concentrations were: pulp density 10%, time 0.5h, temperature 110?C, NH3NH2HSO4 3.25 g/10g, H2SO4 2.0% (v/v) for 96.9% Mn, 85.25% Cu, 92.58% Ni and 76.5% Co extractions. More than 92% Mn could be leached from different types of ores by varying amount of reductant and acid concentration at 35?C. Depending on Mn content 1.0 to 1.2 times stochiometric amount of reductant and 1.5 to 1.8 times sulphuric acid were required for >92% Mn extraction.

Leaching of copper, nickel and cobalt from Indian Ocean manganese nodules by Aspergillus niger

The leaching of copper, nickel and cobalt from polymetallic manganese nodules from the Indian Ocean was investigated using a fungus — Aspergillus niger. Parameters such as initial pH, pulp density, particle size and duration of leaching were optimized for the bio-recovery of metals. At an initial pH of 4.5, 35 ºC temperature and 5% (w/v) pulp density, about 97% Cu, 98% Ni, 86% Co, 91% Mn and 36% Fe were dissolved in 30 days time using adapted fungus — as against only 4.9% Cu, 8.2% Ni, 27% Co, 6.3% Mn and 7.1% Fe solubilized in control experiment. The results indicate that A. niger released organic acids such as oxalic and citric acids which in turn reduced the host metal oxides/hydroxides to their lower valence states, and thus dissolving the base metals following the indirect mechanism. A comparison of results obtained with chemical leaching of sea nodules using citric and oxalic acids and bio-leaching using A. niger show that the leaching of metals was more effective in presence of the fungus. The appearance of some lower oxide phases of manganese and iron in the leach residue identified by XRD phase analyses may account for unlocking of the host lattice leading to release and dissolution of metals during leaching.

Manganese metallurgy review. Part I: Leaching of ores/secondary materials and recovery of electrolytic/chemical manganese dioxide

The world rapidly growing demand for manganese has made it increasingly important to develop processes for economical recovery of manganese from low grade manganese ores and other secondary sources. Part I of this review outlines metallurgical processes for manganese production from various resources, particularly focusing on recent developments in direct hydrometallurgical leaching and recovery processes to identify potential sources of manganese and products which can be economically produced.High grade manganese ores (>40%) are typically processed into suitable metallic alloy forms by pyrometallurgical processes. Low grade manganese ores (<40%) are conventionally processed by pyrometallurgical reductive roasting or melting followed by hydrometallurgical processing for production of chemical manganese dioxide (CMD), electrolytic manganese (EM) or electrolytic manganese dioxide (EMD).Various direct reductive leaching processes have been studied and developed for processing low manganese ores and ocean manganese nodules, including leaching with ferrous iron, sulfur dioxide, cuprous copper, hydrogen peroxide, nitrous acid, organic reductants, and bio- and electro-reductions. Among these processes, the leaching with cheap sulfur dioxide or ferrous ion is most promising and has been operated in a pilot scale. The crucial issue is the purification of leach liquors and the selective recovery of copper, nickel and cobalt is often difficult from solutions containing soluble iron and manganese. For treatment of manganese bearing materials including waste batteries, spent electrodes, sludges, slags and spent catalysts, a leaching or reductive leaching step is generally needed followed by various purification steps, which makes the processes less economically viable.It is concluded that the recovery of manganese from nickel laterite process effluents which contain 1–5 g/L Mn offers a growing low cost resource of manganese. Part II of this review considers the application of various solvent extraction reagents and precipitation methods for treating such manganese liquors.

Esterification of acetic acid with n-butanol over manganese nodule leached residue

Manganese nodule leached residue (MNLR) was obtained as waste material after selective extraction of Cu, Co and Ni from Indian Ocean manganese nodule. MNLR was washed with water to remove sulphate and other impurities present in its surface. The catalytic activity of the waste material was tested for liquid phase esterification of acetic acid with n-butanol. The effect of reaction time, catalyst amount, temperature and mole ratio of reactants on esterification was studied to optimize the reaction conditions. Water-washed manganese nodule leached residue (WMNLR) calcined at 400°C shows highest catalytic activity with 76.6% conversion having 100% selectivity towards n-butyl acetate. Esterification reaction follows first order kinetics with respect to acid and 0th order with respect to n-butanol. Conversion of C1–C4 aliphatic acids with n-butanol follows the following order: formic>acetic>proponoic>n-butyric.