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Article

Extraction of Cobalt and Manganese from Ferromanganese Crusts Using Industrial Metal Waste through Leaching

by
Kevin Pérez
1,
Norman Toro
2,*,
Pedro Robles
3,
Felipe M. Galleguillos Madrid
4,
Edelmira Gálvez
5,
Francisco Javier González
6,
Egidio Marino
6,
Jonathan Castillo
7,
Ingrid Jamett
8 and
Pía C. Hernández
1,8,*
1
Departamento de Ingeniería Química y Procesos de Minerales, Facultad de Ingeniería, Universidad de Antofagasta, Antofagasta 1240000, Chile
2
Faculty of Engineering and Architecture, Universidad Arturo Prat, Iquique 1110939, Chile
3
Escuela de Ingeniería Química, Pontificia Universidad Católica de Valparaíso, Valparaíso 2340000, Chile
4
Centro de Desarrollo Energético Antofagasta, Universidad de Antofagasta, Antofagasta 1240000, Chile
5
Departamento de Ingeniería Metalúrgica y Minas, Universidad Católica del Norte, Antofagasta 1270709, Chile
6
Instituto Geológico y Minero de España (IGME-CSIC), Ríos Rosas, 23, 28003 Madrid, Spain
7
Departamento de Ingeniería en Metalurgia, Universidad de Atacama, Copiapó 1531772, Chile
8
Centro de Economía Circular en Procesos Industriales (CECPI), Facultad de Ingeniería, Universidad de Antofagasta, Antofagasta 1270300, Chile
*
Authors to whom correspondence should be addressed.
Metals 2024, 14(9), 1044; https://doi.org/10.3390/met14091044
Submission received: 2 August 2024 / Revised: 2 September 2024 / Accepted: 6 September 2024 / Published: 13 September 2024
(This article belongs to the Special Issue Flotation and Leaching Processes in Metallurgy (2nd Edition))
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Versions Notes

Abstract

:
Ferromanganese crusts are mineral resources distributed in the planet’s oceans. These deep-sea minerals stand out for their abundance and diversity of metals, with Mn and Co being the most abundant elements. These minerals are a good alternative to diversify the extraction of elements, which today are found at low grades on the Earth’s surface. For the co-processing of ferromanganese crusts to recover Co and Mn, there are few studies. These generally worked with the use of a reducing agent, and in many cases previous roasting processes. In the present investigation, two ferromanganese crusts that were collected from two seamounts in the central eastern Atlantic Ocean were characterized. Subsequently, these crusts were leached in an acid-reducing medium, adding steel waste (slag) with 99.73% Fe3O4 and 0.27% metallic iron from the steel industry as a reducing agent. Acid-reducing processes have previously been shown to yield high and rapid recoveries of Co and Mn from seabed minerals. However, there is no previous study using smelting slag as a reducing agent for the treatment of ferromanganese crusts. The best results of this research were obtained when working at 60 C, achieving joint extractions of Co and Mn of ~80% and ~40%, respectively, in 10 min. In addition, the process residues were analyzed, and the formation of contaminating elements or the precipitation of Co and Mn species was not observed.

1. Introduction

Ferromanganese (Fe-Mn) crusts represent a globally distributed mineral resource found in vast areas of the world’s oceans [1,2]. These crusts appear at depths ranging from 400 to 7000 m, primarily covering the flanks of underwater seamounts, ridges, and plateaus [3,4]. Fe-Mn Crusts were formed during intervals devoid of volcanic activity and are characterized by minimal sedimentation at the seamount interface with substantial volumes of ocean water [5,6,7], originating through either hydrothermal-hydrogenic or hydrogenic-diagenetic processes, as illustrated in Figure 1 [8,9,10]. Fe-Mn crusts exhibit a porous surface, characterized by a dark brown or black hue, with a distinctive spherical shape. Internally, these crusts display laminated, massive, columnar, and/or botryoidal textures. Ranging in thickness from 0.1 cm to 26 cm, the most substantial deposits rich in metals are typically encountered at depths ranging from 800 to 2500 m [11,12,13].
Undoubtedly, the principal attribute elevating the value of Fe-Mn crusts as a mineral resource lies in their remarkable abundance and diversity of metals, i.e., their polymetallic nature [15,16]. These include, but are not limited to, Co, V, P, Cd, As, Mo, Sr, Te, Ni, Ba [17,18,19] heavy and light rare earth elements, as well as the complete spectrum of platinum group elements [20,21,22], as outlined in Table 1.
The extensive array of elements present in Fe-Mn crusts plays a pivotal role in fostering the sustainable development of clean technologies, crucial for transitioning towards a reduction in carbon dioxide emissions. These technologies heavily rely on what are termed “critical raw materials”, a group of 34 substances recognized for their significance and scarcity in terms of Earth’s surface reserves. Notably, Fe-Mn crusts encompass over 10 of these 34 critical raw materials, as detailed in Table 2. The term “energy-critical elements” was created by a joint committee of the American Physical Society and Materials Research Society assembled in 2009 to investigate the material resources available to support emerging energy technologies [23,24]. Security of mineral supply has been identified by the European Commission as a priority challenge facing the raw materials sector.
It is essential to emphasize that overexploitation and the constant decrease in the grades of mineral deposits on Earth’s surface have caused an increase in production by mining companies in order to counteract this situation [25,26,27]. However, this practice entails the creation of significant environmental liabilities, such as the accumulation of large quantities of land and underwater waste during flotation processes, which is the most widely used metal recovery method globally [28]. Moreover, the uneven distribution of critical metals across Earth’s surface creates geopolitical tensions among major world powers. This is fueled by the limited supply available on the market in comparison to the soaring demand for these essential resources [6]. In response to the aforementioned scenario, underwater mining emerges as a promising alternative for metal extraction, with ferromanganese crusts standing out as a valuable resource for recovering cobalt and manganese. It is estimated that substantial quantities of these two elements are predominantly located in seabed reserves, making underwater mining an attractive prospect [29]. Limited research exists on the co-processing of ferromanganese crusts to extract cobalt and manganese. Typically, this involves leaching processes utilizing a reducing agent, with some instances incorporating preliminary roasting procedures.
Ju et al. [30] processed Fe-Mn crusts using a roasting method, incorporating sawdust as a reducing agent at a temperature of 723.15 K, followed by leaching at room temperature with a liquid/solid ratio of 10. The addition of sulfuric acid at a concentration of 0.5 mol/L resulted in impressive extractions, achieving 98.47% for cobalt and 99.32% for manganese within a 30 min timeframe. In another way, Inoue and Kawahara et al. [31] used an ammonia solution and SO2 as a reducing agent at moderate temperature (60 °C), pulp density of 2 g/L, SO2 150 mL/min, and ammonium carbonate at 1 mol/L, and extractions of 97% cobalt and 6% manganese were obtained in 120 min. Nakazawa and Sato [32] conducted bacterial leaching employing Thiobacillus ferrooxidans in an acidic medium (H2SO4), with elemental sulfur serving as the reducing agent and a pulp density of 0.1% (0.15 g of sample per 150 mL of leaching solution). Remarkably, researchers successfully extracted 90% cobalt and 70% manganese within an 18-day timeframe. Shibata et al. [33] worked with an acid-reducing medium, using H2O2 at 0.0365 mol/L, HCl at 0.1 mol/L, and 25 °C, achieving extractions of 90% Mn and 92% Co in 40 min. Furthermore, the researchers indicates that without the presence of an oxidizing agent, it was necessary to work at 3 mol/L of HCl and 30 °C to extract 95% Mn and 94% Co in 90 min. Niinae et al. [34] used ammonium sulfate and ammonium thiosulfate as reducing agents, ammoniacal solution (NH4)2SO3 at a concentration of 0.1 mol/L, and temperature of 70 °C, achieving extractions of 63% Mn and 39% Co in 120 min.
Conversely, in the context of employing steel slag as a reducing agent in an acidic medium for the simultaneous dissolution of cobalt and manganese, a recent investigation conducted by Pérez et al. [29] offers valuable insights. Exploring the dissolution of marine nodules at ambient temperature reveals the feasibility of this process, as evidenced by the reactions outlined in Table 3. These reactions, characterized by highly favorable Gibbs free energy values, were employed in a recent study. The researchers achieved extractions of 80% manganese and 35% cobalt within a 15 min timeframe employing a reducing agent ratio of 1/2 (nodules/steel slag) at room temperature. Intriguingly, under identical conditions, but at an elevated temperature of 60 °C, extractions surged to 98% for manganese and 55% for cobalt within the same 15 min duration.
Chile has an exclusive economic zone (EEZ) of 4,264,560 km2 with various underwater mineral resources, such as manganese nodules, underwater polymetallic sulfides, ferromanganese crusts, marine phosphorites, and submarine gas hydrates. In particular, for ferromanganese crusts, significant quantities are found in the volcanic ridge of which the Salas and Gómez, San Félix, and San Ambrosio islands are a part, and also the sedimentary basins that surround Easter Island, where these resources have significant concentrations of manganese (10%) [35]. On the other hand, Chile is a sulfuric acid-producing country and has extensive facilities for the treatment of minerals by hydrometallurgical means, which could be left unused due to the country’s production plan for the year 2030 to increase the treatment of materials through flotation processes to compensate for the drop in copper grades by increasing production. For the reasons previously stated, it is necessary to look for new alternative sources of valuable elements for processing by hydrometallurgical routes that are less polluting to the environment compared to flotation and pyrometallurgy.
In the present manuscript, a novel acid-reductive leaching mechanism is proposed by reusing steel residue (slag) from the steel industry in Chile for the joint recovery of cobalt and manganese from ferromanganese crusts.

2. Materials and Methods

2.1. Ferromanganese Crusts

Samples Drago 0511/DR04-15 and Subvent 1/DA06-4 were recovered by dredge on the seamounts Echo and Gaire (central eastern Atlantic Ocean) during two cruises performed by the Geological Survey of Spain (IGME): Drago 0511 and Subvent 1 aboard the Spanish R/V Miguel Oliver and R/V Hesperides, respectively (Table 4).
The Echo and Gaire seamounts form part of the Canary Island Seamount Province, one of the biggest and most ancient volcanic and metallogenic provinces in the Atlantic Ocean [22]. Co-rich ferromanganese crust deposits cover the substrate rocks and sediments on the tops and flanks of the seamounts. Echo Seamount is a shallow guyot type seamount located in the southwest of the Canary Islands archipelago. Its morphology is represented by a flat top, summit at 253 m depth, and steeped slopes of different degrees. Guyot-type seamounts have this morphology due that during their history could be passed an islands period with sub-aerial and marine processes of erosion. Gaire Seamount is an elongated NNO-SSE volcanic submarine hill, along with a secondary smaller cone separated by a short east-west dorsal. This seamount rises from ca. 4900 m depth to 4600 m depth with stepped flanks and measuring 6 km in length and 5 km in width in the area of the secondary cone.
Mineralogical and petrographic analyses were conducted at IGME-CSIC laboratories on polished thin sections (ca. 30–120 μm thick) using a DM2700P Leica microscope (Leica, Wetzlar, Germany) coupled with a DFC550 digital camera. X-ray powder diffraction (XRD) was performed using a PANalytical X’Pert PRO diffractometer (Philips Analytical, Almelo, The Netherlands), with CuKα radiation, carbon monochromator and automatic slit. The analytical conditions were: CuKα radiation at 40 kV and 30 mA, a curved graphite secondary monochromator, scans from 2° to 70° (2θ), step size of 0.0170° (2θ) and step time 0.5°/min.
Bulk geochemistry of Fe and Mn was determined at IGME-CSIC using X-ray fluorescence (XRF) on PANalytical’s Zetium (Malvern Panalytical, Almelo, The Netherlands) equipment with a rhodium tube and fused pearl preparation (SuperQ, Malvern Panalytical, Almelo, The Netherlands). The accuracy of the data was verified using international standard NOD-A-1 (USGS), and precision was found to be better than ±5%. Analytical conditions were 50 kV voltage and 50 mA. The obtained contents were compared with certified international standards.
Trace Co, Ni, Cu and REY (rare earth elements plus yttrium) were analyzed using inductively coupled plasma mass spectrometry (ICP-MS) (Agilent 7500 ce, Agilent Technologies, Santa Clara, CA, USA) and inductively coupled plasma atomic emission spectroscopy (ICP-AES) (Varian Vista-MPX, Varian Inc., Palo Alto, CA, USA) measurements for Co and Ni. For these techniques, samples were prepared with an ultrapure 3-acid digestion (HF, HNO3, and HCl), dried until almost complete dryness, and the residuals were diluted with HCl 10%.

2.2. Iron Residue

The steel residue utilized, “slag” was sourced from the steel smelting operations of the CAP Company in Antofagasta, Chile. This residual material contained 82.65% Fe3O4, 13.03% Fe2O3, and 0.27% metallic iron (See Table 5). Initially ranging in size from 1 to 10 mm, it underwent size reduction in a mortar, resulting in particles sized between −140 and +100 µm.

2.3. Leaching Test

The leaching tests were carried out in a 200 mL glass reactor at 0.1 solid-to-liquid ratio (100 mL of acid solution (H2SO4) and Fe-Mn crust/Fe(res) ratio of 1/2. A total of 10 g of the mineral (ferromanganese crust) was kept under agitation and suspension using a 5-position magnetic stirrer (IKA ROS, CEP 13087-534, Campinas, Brazil) at 600 rpm and a particle size of −177 to +149 µm. The temperature was controlled using an oil-heated circulator (Julabo, St. Louis, MO, USA). The temperature range tested in the experiments was 25 to 60 °C. All tests were performed in duplicate, and analyses were carried out using 5 mL undiluted samples and AAS with a ≤5% variation quotient and 5–10% relative difference. The pH and oxidation-reduction potential were measurements of the leaching solutions and were carried out in a pH-ORP meter (HANNA HI-4222, St. Louis, MO, USA). The ORP solution was measured using an ORP electrode cell composed of a platinum-employed electrode and a saturated Ag/AgCl reference electrode.

3. Results and Discussion

3.1. Sample Characterization

The thickness of cobalt-rich ferromanganese crusts is 2.5 cm for Drago 0511/DR04-15 and 6.4 cm for Subvent 1/DA06-4. They show subspherical botryoids and sometimes current-smoothed upper surface with the appearance of typical hydrogenic crusts formed at the seafloor. Both crusts show a general internal layered pattern of typical black hue with a dark-brown layer covering volcanic rock substrate in the sample Subvent 1/DA06-4 and semi-consolidated carbonate sediments in the Drago 0511/DR04-15 (Figure 2). Polished sections of cut samples of crusts under the reflected light microscope show different internal structures: massive, dense to porous, and mottled.
The crusts are composed of poorly crystalline Fe and Mn oxyhydroxides. Fe–vernadite is the main Mn mineral with minor amounts of other Mn oxides such as asbolane and goethite as the main Fe minerals (Figure 3). Light-colored and porous thin laminations intercalated between massive and dense textures, abundant in the sample Subvent 1/DA06-4, correspond essentially to siliciclastic detrital accumulation. In addition to Fe-Mn oxyhydroxides, microscopic and XRD studies show the presence of small amounts of minority minerals, represented essentially by silicates (detrital quartz and feldspars and authigenic clays), carbonates (authigenic calcite and bioclastic accumulation), and authigenic phosphates (carbonate fluorapatite).
Bulk chemistry of both crusts reflects the main mineralogy (Table 6), showing high average contents of Fe (19.6 wt. %) and Mn (15.1 wt. %) and lower amounts of the other major elements (in total <15%). The sample Subvent 1/DA06-4 shows major abundance of siliciclastic elements (SiO2 13.8 wt. % and Al2O3 5.3 wt. %), and the sample Drago 0511/DR04-15 exhibits higher contents of elements linked to phosphates (CaO 6.05 wt. % and P2O5 2.47 wt. %) (Table 6). Among the trace elements, the crusts are enriched in many critical and strategic elements highlighted in this study: Co (up to 4262 µg/g), Ni (up to 2844 µg/g), Cu (up to 1342 µg/g), and rare earth elements plus yttrium (up to 2323 µg/g).
The sum of the major elements and their LOI (loss on ignition) reach 94 and 98 wt. %, respectively, which is within the error calculated for this kind of sample, characterized by high hygroscopy. Humidity calculated before the LOI of both samples is 21.3% and 6.4% respectively.

3.2. Leaching Ferromanganese Crusts

Figure 4 and Table 7 illustrates the outcomes of the manganese and cobalt extraction from the studied ferromanganese crusts. The data reveal a positive correlation between the temperature of the system and the recovery of both elements, aligning with findings from prior studies on the dissolution of these elements from underwater resources [14,36]. Although there are no previous studies on recovering metals from ferromanganese crusts under the same operational conditions used in this research, a recent study undertook a project focused on extracting cobalt (Co) and manganese (Mn) from marine nodules [29]. This involved utilizing an acid-reducing medium along with the addition of steel scrap. Table 8 contrasts the findings from Pérez et al. [29] with the outcomes of the present investigation. Notably, under similar dissolution times and conditions, except for a slightly reduced particle size in the manganese nodules in Pérez et al. [29] research, a noteworthy disparity emerges. Greater manganese extractions from the marine nodules are evident, likely attributed to their higher concentration of Fe3O4 in the chemical composition, thereby enhancing acid-reducing dissolution. Additionally, in line with the hypothesis put forth by [author’s name], it is conceivable that the presence of gangue surrounding larger particles (Fe-Mn crusts) impedes diffusion rates. This hindrance can result in a decrease in reactant concentration, diminishing the driving force for mass transfer and consequently slowing down the reaction rate [37,38,39].
Regarding the redox potential and pH values, as described in previous studies [29,39], to effectively dissolve manganese in an acid-reducing medium (using iron), it is necessary to work in pH ranges from −2 to 8 and potential ranges between 1.4 and −1.2 V, while for cobalt. it is necessary to work in pH ranges from −2 to 4.5 and potential ranges between 0.8 and −0.25 V. In the results presented in Figure 5, it can be seen that for the dissolution of manganese in the two samples and temperatures studied was within a range of potential and pH that favor the dissolution of this element, while for cobalt, it can be observed that working at room temperature (25 °C) tends to increase the potential of the system after 5 min, working in ranges that are not appropriate to effectively dissolve the Co.

3.3. Residue Analysis

The waste from the two examined samples shows an absence of contaminating elements. Moreover, as highlighted in a prior study by Toro et al. [39], the elevated concentration of ferric and ferrous ions within the system enables operation within potential redox and pH ranges conducive to manganese dissolution, thereby preventing precipitation. Additionally, a recent investigation by Pérez et al. [29] demonstrated a similar effect in the context of cobalt, affirming that working in an acid-reducing medium with high concentrations of iron yields analogous favorable outcomes.

3.3.1. Drago 0511/DR04-15

Figure 6 shows the majority composition found by SEM-EDS of Si/S/O, Fe/S/O and Fe/O, associations of impurities of Al/Si/S/O, Mg/Si/O, and Fe/O, and Mn associations found from Fe/Mg/S/O with a size range from 8.3 µm to 13.7 µm long.
Figure 7 depicts an agglomeration of Fe/S/O particles, distinguished by red coloring in (1), green in (2), blue in (3), and green in (4). Furthermore, impurities manifest in associations such as Fe/Mn/S/O (indicated by purple coloration in (1), cyan in (2) and (3), and green in (4)), Mg/Si/O (with green coloration in (1), red in (2) and (3), and fuchsia in (4)), Si/S/O (displaying green in (1), orange in (2), fuchsia in (3), and orange in (4)), and Fe/O (red in (1), no coloration in (2), (3), or (4)) can be seen. The Fe/Mn/S/O particles exhibit lengths of 13.7 µm and 8.2 µm. Importantly, the analysis confirms the absence of contaminating elements and the non-precipitation of cobalt and manganese compounds (refer to Figure 8).

3.3.2. Subvent 1/DA06-4

Figure 9 illustrates the predominant composition identified through SEM-EDS, featuring the elemental combinations of Fe/S/O and Si/S/O. Additionally, impurity associations include Si/O, Ca/S/O, Ca/Mg/Fe/Si/O, Fe/O, Al/Si/S/O, and Al/Si/O. The Mn associations are identified as Mn/S/O, ranging in size from 4.5 µm to 12.3 µm in length.
Figure 10 provides a detailed view of an agglomeration of particles featuring Fe/S/O associations, distinguished by blue coloration in (1), purple in (2), red in (3), and without coloration in (4). Within this agglomerate, impurities manifest through associations such as Mn/S/O (indicated by cyan in (1), red in (2), pink in (3), and green in (4)), Ca/S/O (with pink in (1), olive green in (2), and without coloration in (3)), Al/Si/S/O (blue in (1), red in (2), olive green in (3), and pink in (4)), Si/S/O (exhibiting blue in (1), red in (2), olive green in (3), and red in (4)), and Al/Si/O (noted by no coloration in (1) or (2), green coloration in (3), and fuchsia in (4)). The Mn/S/O particles range in size from 4.5 µm to 12.3 µm in length. Similar to sample 1, there is no evidence of contaminating element formation in this sample (refer to Figure 11).

4. Conclusions

In the present investigation, the dissolution of Co and Mn was studied from two ferromanganese crusts recovered by dredge from two seamounts in the central eastern Atlantic Ocean. For this, this work was carried in an acid medium (0.1 mol/L of H2SO4)—reducer (steel residue (Fe-Mn crust/Fe(res) ratio of 1/2). at a medium temperature (25–60 °C) The main findings are detailed below.
  • Studied samples have a general hydrogenic origin formed essentially by Fe-vernadite with some diagenetic influence highlighted by the presence of 10 A Mn oxides (asbolane/buserite). Fe oxyhydroxides are represented essentially by goethite-group minerals. Geochemistry reflects the mineralogy with high contents of Fe and Mn (between 15 and 20 wt. %) and great contents of several CRM as Co, Ni, Cu and REE + Y (average 3300, 2600, 900 and 2300 µg/g, respectively).
  • A slight increase in the potential of the system was observed after 5 min of work at room temperature, which implies a decrease in the cobalt dissolution, because it is not possible to stably maintain the ideal redox potential range (0.8 to −0.25 V).
  • The best results of this research were obtained when working at 60 °C, achieving joint extractions of Co and Mn of ~80% and ~40%, respectively, in 10 min.
  • Precipitation of cobalt and manganese species is not observed in the residues studied.
In future work, it is necessary to investigate the purification of the PLS obtained in the present investigation, and in addition, the precipitation of Mn and Co. For following investigations, we put forth the technological flowchart presented in Figure 12 as an economical proposal to recover cobalt and manganese from ferromanganese crusts. In stage 1, the leaching mechanism presented in this manuscript is proposed, where Fe-Mn crust, H2SO4, and smelter slag are added in a stirred reactor. The product is a PLS rich in Mn and Co, which in stage 2 is put in contact with zero-valent iron (this is a good low-cost alternative, since it can be reused from metal finishing industry waste) to precipitate the manganese present in the solution. Then, in stage 3, the Co-rich PLS is concentrated (cleaned) in a solvent extraction stage, and finally in stage 4, the Co is recovered by electrowinning.

Author Contributions

Conceptualization, K.P. and F.M.G.M.; validation, I.J.; investigation, K.P., N.T., P.R., F.M.G.M., E.G., E.M., J.C. and P.C.H.; resources, P.R. and E.G.; writing—original draft preparation, K.P., N.T. and P.C.H.; writing—review and editing, E.G., F.J.G., E.M., J.C. and I.J.; supervision, N.T. and P.C.H.; funding acquisition, F.J.G. and E.M. All authors have read and agreed to the published version of the manuscript.

Funding

This research was funded by a European Horizon project (GSEU CL5-2021-D3-02-14, project 101075609).

Data Availability Statement

The raw data supporting the conclusions of this article will be made available by the authors on request.

Acknowledgments

Pedro Robles thanks the Fondecyt 1221702 project for supporting this investigation and the Pontificia Universidad Católica de Valparaiso for the support provided. Kevin Perez acknowledges the infrastructure and support of the PhD Program in Mineral Processes Engineering of the Universidad de Antofagasta. Felipe M. Galleguillos Madrid thanks the ANID/ FONDAP 1522A0006 Solar Energy Research Center SERC-Chile and ANID through research grant FONDECYT N° 11230550.

Conflicts of Interest

The authors declare no conflicts of interest.

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Metals 14 01044 g001
Figure 1. Formation of ferromanganese crusts (modified from [14]).
Figure 1. Formation of ferromanganese crusts (modified from [14]).
Metals 14 01044 g001
Metals 14 01044 g002
Figure 2. Image of Fe-Mn crust samples selected for this study. (A) Crust Drago 0511/DR04-15 was dredged from Echo Sm. (B) crust Subvent 1/DA06-4 from Gaire Sm.
Figure 2. Image of Fe-Mn crust samples selected for this study. (A) Crust Drago 0511/DR04-15 was dredged from Echo Sm. (B) crust Subvent 1/DA06-4 from Gaire Sm.
Metals 14 01044 g002
Metals 14 01044 g003
Figure 3. (A,B) X-ray diffraction (XRD) analysis of bulk samples. In samples Drago 0511/DR04-15 and Subvent 1/DA06-4, is possible recognize Fe oxyhydroxides represented by goethite-group (Gth) minerals and Mn oxides, essentially Fe-vernadite (Ver). In sample Subvent 1/DA06-4, it is also possible to recognize ~10 Å reflection due to the presence of todorokite (Tod), asbolane (Asb) or buserite (Bus), feldspars (Fsp) and peaks of carbonate-fluorapatite (CFA). Calcite (Cal) was detected in Drago 0511/DR04-15, and quartz (Qtz) peaks are shown in both samples.
Figure 3. (A,B) X-ray diffraction (XRD) analysis of bulk samples. In samples Drago 0511/DR04-15 and Subvent 1/DA06-4, is possible recognize Fe oxyhydroxides represented by goethite-group (Gth) minerals and Mn oxides, essentially Fe-vernadite (Ver). In sample Subvent 1/DA06-4, it is also possible to recognize ~10 Å reflection due to the presence of todorokite (Tod), asbolane (Asb) or buserite (Bus), feldspars (Fsp) and peaks of carbonate-fluorapatite (CFA). Calcite (Cal) was detected in Drago 0511/DR04-15, and quartz (Qtz) peaks are shown in both samples.
Metals 14 01044 g003
Metals 14 01044 g004
Figure 4. Manganese and cobalt extraction from ferromanganese crusts. (A): Drago 0511/DR04-15 (B): Subvent 1/DA06-4.
Figure 4. Manganese and cobalt extraction from ferromanganese crusts. (A): Drago 0511/DR04-15 (B): Subvent 1/DA06-4.
Metals 14 01044 g004
Metals 14 01044 g005
Figure 5. Effect of potential and pH on the extraction of Mn and Co from ferromanganese crusts.
Figure 5. Effect of potential and pH on the extraction of Mn and Co from ferromanganese crusts.
Metals 14 01044 g005
Metals 14 01044 g006
Figure 6. Scanning electron microscopy (SEM-EDS) micrograph of residue of Drago 0511/DR04-15. Magnification 1250×.
Figure 6. Scanning electron microscopy (SEM-EDS) micrograph of residue of Drago 0511/DR04-15. Magnification 1250×.
Metals 14 01044 g006
Metals 14 01044 g007
Figure 7. SEM micrograph with EDS analysis (color change) of residue Drago 0511/DR04-15. Magnification 1250× (70 µm).
Figure 7. SEM micrograph with EDS analysis (color change) of residue Drago 0511/DR04-15. Magnification 1250× (70 µm).
Metals 14 01044 g007
Metals 14 01044 g008
Figure 8. Scanning electron microscopy elemental analysis for sample Drago 0511/DR04-15 (SEM-EDS).
Figure 8. Scanning electron microscopy elemental analysis for sample Drago 0511/DR04-15 (SEM-EDS).
Metals 14 01044 g008
Metals 14 01044 g009
Figure 9. Scanning electron microscopy (SEM-EDS) micrograph of residue of Subvent 1/DA06-4. Magnification 1400×.
Figure 9. Scanning electron microscopy (SEM-EDS) micrograph of residue of Subvent 1/DA06-4. Magnification 1400×.
Metals 14 01044 g009
Metals 14 01044 g010
Figure 10. SEM micrograph with EDS analysis (color change) of residue Subvent 1/DA06-4. Magnification 1400× (20 µm).
Figure 10. SEM micrograph with EDS analysis (color change) of residue Subvent 1/DA06-4. Magnification 1400× (20 µm).
Metals 14 01044 g010
Metals 14 01044 g011
Figure 11. Scanning electron microscopy elemental analysis for sample Subvent 1/DA06-4 (SEM-EDS).
Figure 11. Scanning electron microscopy elemental analysis for sample Subvent 1/DA06-4 (SEM-EDS).
Metals 14 01044 g011
Metals 14 01044 g012
Figure 12. Technological flowchart proposal.
Figure 12. Technological flowchart proposal.
Metals 14 01044 g012
Table 1. Representative chemical compositions of ferromanganese crusts within Canary Island Seamount Province exploration areas (adapted from [22]).
Table 1. Representative chemical compositions of ferromanganese crusts within Canary Island Seamount Province exploration areas (adapted from [22]).
Echo SeamountPaps SeamountDrago SeamountTropic Seamount Atlantic MeanPacific MeanIndian Mean
SampleDR2-9DR3-1DR04-14DR7-8DR9-10DR9-11DR10-7DR11-2DR14-1DR13-11DR13-12DR13-13DR15-14ADR15-15DR16-5DR16-13MeanMin.Max.St. Dev.n = 25 + 18 + 13n = 2339n = 14
Fe (wt. %)26.4822.7225.9913.5520.2721.4924.7215.5826.5818.9126.0627.5826.5126.996.9828.3323.4513.5528.334.5618.8419.2723.6
Mn17.5314.1817.6613.0413.8214.4817.697.7219.0112.0518.2218.8416.9418.774.9221.7416.117.7221.743.5314.6821.3715.6
Mn/Fe0.660.620.680.960.680.670.720.500.720.640.700.680.640.700.700.770.690.500.960.100.781.110.66
SiO25.4512.476.3918.4819.3216.3311.685.705.1112.186.806.578.147.508.003.659.723.6519.325.0710.4212.817.78
Al2O32.605.133.236.606.214.943.972.652.754.513.113.113.042.992.521.293.741.296.601.463.872.911.34
CaO3.374.003.118.192.652.983.2225.254.4512.205.042.995.593.5833.033.496.012.6525.255.892.534.280.75
TiO21.652.471.301.041.681.551.751.761.841.531.631.641.451.590.551.241.611.042.470.321.291.631015
K2O0.430.900.500.750.880.690.500.270.410.950.450.510.450.400.490.330.560.270.950.222.10.742.32
MgO2.212.962.264.482.732.512.041.792.252.001.961.981.892.041.791.902.331.794.480.682.172.041.72
P2O51.321.711.253.781.171.281.200.842.016.401.151.121.191.2118.081.091.780.846.401.461.431.560.38
Na2O1.701.621.561.671.932.471.761.131.811.501.521.941.582.121.381.771.741.132.470.311.92.322.24
H2O12.9510.7111.777.5610.5311.212.426.0611.398.7110.3211.7111.6513.173.9512.5910.856.0613.172.0111.215.3812.8
LOI26.9223.9026.3122.8723.6324.6725.7331.0825.7421.9626.2525.9026.8026.7417.3827.1525.7121.9631.082.17-28.73-
Co (µg/g)515753754245356042393767450242306745335948875090383446641698716947223359716910863919.54770.753126
V307221483143132618622005246510352446152725682830264327964323614236510353614716813.37584624
Zn754721670672656718709373708489669735625694356899673373899118570.67655.58533
Ni244327372252603632382734275615023558197224202513199424052481292427661502603610382326.853777.332558
Cu47653926115739696377714797985556519263955424903876642611573321798.78892.421254
Mo456354511214282355379103440283454504437457136644392103644133383.89435.92330
W10091129384428902911550114138951063284832913836.6279.6379.4478
Pb2284170722248261307148617368281762115716581861159518193372106162482622844451128.1315021058
As4784334792553793894163254703104394584694129956341825556378316.28329.08181
Tl728713795956171501165681112606031127855013728106.31100.3689.4
Ba45252893467317012474264935101031206139064601296434804086101558413360103158411286140719971668
Nb981389711611910012515412210010112389882785110851542052.6736.1774
La380343397172222276330189422330390412374402364402.333617242283265.26292.25286
Ce1913166318596921329140216941190177312831834200017621942449.772176163469221763861446.341157.081481
Pr82.7173.3688.1834.4046.2758.4570.3435.8789.2769.4586.3193.2282.9791.216189.9272.7934.4091.212064.3260.7768.8
Nd335299360150190240287143363285350375341373260.2836229714337581245.62251.67248
Sm67.7860.2573.3331.3740.0150.2359.1528.7473.6956.9671.5976.4571.0876.0149.7774.8260.7628.7476.4516.3156.4551.9560.2
Eu16.3114.5617.687.909.8412.2714.506.9317.4914.0217.0618.1217.2018.2012.7017.5014.646.9318.203.7711.9615.7910.8
Gd78.3570.4482.0639.7048.4059.9168.9735.7781.4866.1679.5081.2180.8184.7663.7277.5769.0135.7784.7616.0762.1552.9262
Tb10.829.8011.565.536.948.679.645.0111.409.4511.2611.4411.4312.098.7510.699.725.5312.092.259.548.839
Dy62.2656.3366.3034.4041.5850.9056.6329.2765.2355.4363.4563.4366.3368.875659.7256.0129.2768.8712.0849.5352.9649.4
Y19922023922517120920112026428522621924622955717321512028540.10167.31179.75163
Ho11.9511.1212.817.338.3010.3411.065.8212.7511.0612.0411.8912.7912.9012.4911.0710.885.8212.902.139.79.539.8
Er32.5130.8035.8221.7424.0329.0530.4916.3935.2131.3332.7832.5135.0935.0137.6929.6330.1616.3935.825.5128.528.426
Tm4.584.284.953.043.494.234.342.364.924.344.574.494.904.875.184.064.232.364.950.743.784.033
Yb28.3726.6530.8318.9322.2426.9127.6315.3330.4727.7128.5527.9830.4530.1733.6325.0526.4915.3330.834.4624.0826.2422.7
Lu4.063.934.432.943.384.004.112.304.594.104.134.024.374.235.283.483.872.304.590.613.83.543.46
%REY0.320.290.330.140.220.240.290.180.320.250.320.340.310.340.200.350.280.180.350.060.240.220.25
%HREY13.915.515.4025.315.717.014.913.120.114.913.816.216.214.840.111.715.511.725.33.2215.1317.4014.35
CeSN/CeSN2.482.412.282.063.012.532.553.302.101.952.302.352.302.330.682.632.441.953.300.352.411.892.3
Ce *0.370.360.340.280.450.380.380.490.300.260.340.350.340.35−0.210.400.360.260.490.060.40.260.38
YSN/HoSN0.480.560.530.880.590.580.520.590.590.740.540.530.550.511.270.450.570.450.880.110.510.560.49
Ru ** (ng/g)10.0911.429.0714.9316.0910.4412.9010.8614.2216.4314.8312.6918.689.72-11.5512.939.0718.682.8417.310.513
Rh **10.5515.908.8116.1217.559.1612.7918.2017.4919.7221.4113.8212.799.89-14.7614.608.8121.413.9230.81324
Pd **5.301.416.451.171.3612.731.4421.29<DL<DL1.492.871712.21-6.2515.66<DL17146.319.93.677
Os **1.001.210.650.931.360.771.071.251.571.871.040.591.340.97-0.981.110.591.870.34---
Ir **3.193.802.743.994.272.653.594.274.334.945.453.783.663.09-3.963.852.655.450.765.84.088
Pt **291160108222213112146159159173321208222103-13818210332164425270.17348
* calculated with methodology explained in Marino et al. [22]. ** Ce anomaly calculated as Ce * = Log (Ce/(2/3La + 1/3Nd)).
Table 2. Raw materials considered critical by the European Union in 2023.
Table 2. Raw materials considered critical by the European Union in 2023.
Critical Raw Materials
AntimonyCobaltGermaniumNatural GraphiteLight rare earths
BerylliumCokeIndiumNiobiumHeavy rare earths
BoratesFluorsparMagnesitePlatinum groupSilicon metals
ChromiumGalliumBismuthPhosphate rocksTungsten
LithiumTitaniumStrontiumBauxiteHafnium
Natural RubberVanadiumWolframTantalumScandium
CopperManganeseNickel
Table 3. Proposed reactions for the dissolution of cobalt and manganese from seabed minerals (adapted from [29]).
Table 3. Proposed reactions for the dissolution of cobalt and manganese from seabed minerals (adapted from [29]).
ReactionΔG° (kJ)Equation
Fe3O4 (s) + 4H2SO4 (l) = FeSO4 (aq) + Fe2(SO4)3 (s) + 4H2O (l)−264.27(1)
2FeSO4 (aq) + 2H2SO4 (aq) + MnO2 (s) = Fe2(SO4)3 (s) + 2H2O (l) + MnSO4 (aq)−221.44(2)
CoO + H2SO4 = CoSO4 + H2O−115.43(3)
Co3O4 + 4H2SO4 + 2FeSO4 = 3CoSO4 + 4H2O + Fe2(SO4)3−354.18(4)
Table 4. Sample location in the seamount, water depth and Fe-Mn crust thickness.
Table 4. Sample location in the seamount, water depth and Fe-Mn crust thickness.
SampleSeamountSample LocationLatitudeLongitudeWater Depth (m)Fe-Mn Crust Thickness (mm)
Drago 0511/DR04-15EchoWest flank25°19.51′ N19°18.92′ W1832–159325
Subvent 1/DA06-4GaireEast flank26°06.20′ N22°09.00′ W482364
Table 5. Chemical analysis of steel residue.
Table 5. Chemical analysis of steel residue.
ElementMass (wt. %)
Fe3O482.65
Fe2O313.03
Fe00.27
CaO0.75
SiO21.5
Al2O30.3
MgO0.2
SO30.08
P2O50.2
K2O0.015
MnO0.8
C0.2
Table 6. Bulk chemistry of samples in selected elements for this study.
Table 6. Bulk chemistry of samples in selected elements for this study.
ElementDrago 0511/
DR04-15A		SUBVEMT/
DA06-4		ElementDrago 0511/
DR04-15A		Subvent/
DA06-4
SiO2 (wt. %)6.9113.80Ag0.17<0.2
Al2O32.865.38Cd1.493.45
Fe2O328.4327.70Sb46.0231.75
Fe19.8819.37Te37.2618.06
CaO6.051.89Ba13741188
TiO21.030.96Tl69.25114.37
MnO18.6920.23Pb1566859
Mn14.4716.66Th31.98108.05
K2O0.470.83U11.498.71
MgO2.362.48Y169134
P2O52.470.80La240209
Na2O1.591.35Ce14201476
LOI22.8123.20Pr49.7056.89
SUM93.6798.62Nd205.00224.76
Mn/Fe0.730.81Sm41.8051.05
Be (µg/g)8.876.48Eu10.2012.19
V940.67674.22Gd49.5053.57
Cr25.0319.78Tb7.047.74
Co42622424Dy42.7043.23
Ni23592844Ho8.717.90
Cu4741342Er25.2021.77
Zn456430Tm3.523.07
As341231Yb22.0020.00
Se21.0629.56Lu3.413.00
Mo383.89376.52ΣREY22982323
Table 7. Chemical concentration of Mn and Co in the solution after leaching presented in Figure 4.
Table 7. Chemical concentration of Mn and Co in the solution after leaching presented in Figure 4.
ManganeseCobalt
(A)25 °C60 °C25 °C60 °C
Time (min)Concentration (g/L)Concentration (g/L)Concentration (g/L)Concentration (g/L)
20.013050,071050,000380,00068
30.030450,098600,000590,00106
50.056550.105850.000890.00127
70.065250.116000.000930.00140
100.082650.123250.001150.00166
(B)25 °C60 °C25 °C60 °C
Time (min)Concentration (g/L)Concentration (g/L)Concentration (g/L)Concentration (g/L)
20.010990.072220.000160.00033
30.029830.100480.000310.00063
50.059660.109900.000460.00077
70.067510.125600.000530.00087
100.086350.131880.000670.00099
Table 8. Comparison of the dissolution of Mn and Co from marine nodules and ferromanganese crusts in an acid-reducing medium.
Table 8. Comparison of the dissolution of Mn and Co from marine nodules and ferromanganese crusts in an acid-reducing medium.
Experimental Conditions and ResultsPérez et al. [29]This Work
Manganese NoduleFerromanganese Crust
Sample 1Sample 2Drago 0511/DR04-15Subvent 1/DA06-4
Temperature (°C)60606060
Particle size (µm)−140 + 100 µm−140 + 100 µm−177 + 149 µm−177 + 149 µm
Sulfuric acid concentration (mol/L)0.10.10.10.1
Mineral resource/iron scrap ratio1/21/21/21/2
Manganese extraction in 10 min (%)90878485
Cobalt extraction in 10 min (%)42404139
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Pérez, K.; Toro, N.; Robles, P.; Galleguillos Madrid, F.M.; Gálvez, E.; González, F.J.; Marino, E.; Castillo, J.; Jamett, I.; Hernández, P.C. Extraction of Cobalt and Manganese from Ferromanganese Crusts Using Industrial Metal Waste through Leaching. Metals 2024, 14, 1044. https://doi.org/10.3390/met14091044

AMA Style

Pérez K, Toro N, Robles P, Galleguillos Madrid FM, Gálvez E, González FJ, Marino E, Castillo J, Jamett I, Hernández PC. Extraction of Cobalt and Manganese from Ferromanganese Crusts Using Industrial Metal Waste through Leaching. Metals. 2024; 14(9):1044. https://doi.org/10.3390/met14091044

Chicago/Turabian Style

Pérez, Kevin, Norman Toro, Pedro Robles, Felipe M. Galleguillos Madrid, Edelmira Gálvez, Francisco Javier González, Egidio Marino, Jonathan Castillo, Ingrid Jamett, and Pía C. Hernández. 2024. "Extraction of Cobalt and Manganese from Ferromanganese Crusts Using Industrial Metal Waste through Leaching" Metals 14, no. 9: 1044. https://doi.org/10.3390/met14091044

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