Galvanic Leaching of Seafloor Massive Sulphides Using MnO2 in H2SO4-NaCl Media

Kowalczuk, Przemyslaw B.; Manaig, Dan; Drivenes, Kristian; Snook, Ben; Aasly, Kurt; Kleiv, Rolf Arne

doi:10.3390/min8060235

Cited by 14 publications

(11 citation statements)

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“…The simultaneous leaching of manganese dioxide and sulfides such as chalcopyrite [9,10], sphalerite [11], and pyrite [12] in acid media has been investigated. In our previous paper [8], we showed that the dissolution rate of metals from SMS was accelerated in the presence of MnO 2 in the H 2 SO 4 -NaCl media. This acceleration was interpreted to be a result of galvanic interactions between the sulfide minerals of the SMS ore, such as chalcopyrite (CuFeS 2 ), isocubanite (CuFe 2 S 3 ), sphalerite ((Zn,Fe)S), pyrite/marcasite (FeS 2 ), and manganese dioxide (MnO 2 ).…”

Section: Introductionmentioning

confidence: 86%

“…Our previous study [8] investigated various factors such as the temperature, H 2 SO 4 concentration, and dosage of NaCl, that could influence dissolution of metals from SMS rock samples in the presence of pure manganese dioxide, as an oxidant. In this paper, we only emphasized changes in time and dosage of polymetallic nodules, while other leaching parameters, such as 1 M H 2 SO 4 , 1 M NaCl, 80 • C, 700 rpm, solid-to-liquid ratio of 50 g/L, were kept constant.…”

Section: Leachingmentioning

confidence: 99%

“…Simultaneous leaching of SMS and PN in the H 2 SO 4 -NaCl media was found to occur due to three possible routes: (i) Galvanic interactions between manganese dioxide and primary marine minerals of SMS (i.e., pyrite, isocubanite, chalcopyrite, sphalerite), (ii) the action of the Fe 3+ /Fe 2+ couple, as well as iii) possible action of chlorine gas generated in the mixed sulfate-chlorite media in the presence of MnO 2 , which has been readily utilized in the redox reaction. The possible dissolution mechanism was described in detail elsewhere [8].…”

Section: Leachingmentioning

confidence: 99%

“…The complex mineralogy and rapid oxidation of SMS provide challenges to conventional beneficiation by flotation [6][7][8], thus a new process to extract metals simultaneously by leaching of SMS and PN is proposed in this paper. The simultaneous leaching of manganese dioxide and sulfides such as chalcopyrite [9,10], sphalerite [11], and pyrite [12] in acid media has been investigated.…”

Section: Introductionmentioning

confidence: 99%

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Simultaneous Leaching of Seafloor Massive Sulfides and Polymetallic Nodules

et al. 2019

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Simultaneous leaching of seafloor massive sulfides (SMS) from Loki's Castle on the Arctic Mid-Ocean Ridge (AMOR) and polymetallic nodules (PN) from Clarion Clipperton Zone (CCZ) of the Central Pacific Ocean was studied. Leaching tests were conducted using sulfuric acid and sodium chloride, at a temperature of 80 • C for 48 h under reflux. The effect of PN-to-SMS ratio was examined. It was shown that simultaneous leaching of two different types of marine resources was possible resulting in high dissolution rates of metals. The proposed process has many advantages as it does not require pyrometallurgical pretreatment, and yields solid products (i.e., silica, barite, elemental sulfur, albite, microcline, muscovite), which might be utilized for various industrial applications.Minerals 2019, 9, 482 2 of 12 of eliminating gas emission, production of potentially recoverable solid residues and generation of acid, which could be recycled to the head of the process. The new approach holds promise for efficient processing of marine mineral resources. Materials and Methods MaterialsThis study utilizes an SMS sample collected from the Loki's Castle active hydrothermal vent field at the Arctic Mid-Ocean Ridge (AMOR), which occurs on the Mohn's Ridge at a depth of approximately 2400 m [16]. The SMS samples were collected as a part of the MarMine cruise [17]. More than 200 kg of loose boulders from the mound flanks were collected via grab sampling. The location and areas of operation are described elsewhere [7,17,18]. In order to prevent oxidation of sulfides, the collected rock samples were bagged, flushed with nitrogen, vacuum sealed, and stored at −21 • C.The polymetallic deep-sea nodules (PN) studied in this research were collected in the license area of Global Sea Mineral Resources (GSR) from Clarion Clipperton Zone (CCZ) of the Central Pacific Ocean. The samples were stored in plastic bags.Mili-Q water ® and analytically grade H 2 SO 4 and NaCl were used in the experiments. Methods

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Section: Introductionmentioning

confidence: 86%

Section: Leachingmentioning

confidence: 99%

Section: Leachingmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Simultaneous Leaching of Seafloor Massive Sulfides and Polymetallic Nodules

et al. 2019

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“…Ultimately, the methods utilised in this detailed mineralogical investigation provided the information necessary to steer downstream mineral processing experiments [58,59]. It was determined that these sulphide phases are extremely fine grained, with an average grain size of 9, 5, 4, and 11 µm for pyrite/marcasite, chalcopyrite, isocubanite, and sphalerite respectively, sub-1.5 µm minimum grain sizes for all minerals (after QEMSCAN analysis at 1 µm pixel spacing), and ubiquitous sub-micron intergrowths of Cu-Fe-S phases.…”

Section: Implications For Mineral Processingmentioning

confidence: 99%

Characterisation of Mineralised Material from the Loki’s Castle Hydrothermal Vent on the Mohn’s Ridge

et al. 2018

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Loki's Castle on the Arctic Mid-Ocean Ridge (AMOR) is an area of possible seafloor massive sulphide (SMS)-style mineralisation under Norwegian jurisdiction, which, due to mounting social pressure, may be a strategic future source of base and precious metals. The purpose of this study is to characterise mineralised material from a hydrothermal vent system on the AMOR in detail for the first time, and to discuss the suitability of methods used; reflected light microscopy, X-ray diffraction (XRD), whole rock geochemistry, electron probe micro-analysis (EPMA), and QEMSCAN. The primary sulphide phases, identifiable by microscopy, are pyrite and marcasite with minor pyrrhotite and galena, but multiple samples from the Loki's Castle contain economically interesting quantities of copper (hosted in isocubanite and chalcopyrite) and zinc (hosted in sphalerite), as well as silver and gold. This reinforces the notion that slow spreading ridges may host significant base metal deposits. Micro-textures (chalcopyrite inclusions and exsolutions in sphalerite and isocubanite respectively) are typically undefinable by QEMSCAN, and require quantitative measurement by EPMA. QEMSCAN can be used to efficiently generate average grain size and mineral association data, as well as composition data, and is likely to be a powerful tool in assessing the effectiveness of SMS mineral processing.

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Conceptual 3D Modeling and Direct Block Scheduling of a Massive Seafloor Sulfide Occurrence

Ellefmo

2022

Perspectives on Deep-Sea Mining

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Galvanic Leaching of Seafloor Massive Sulphides Using MnO2 in H2SO4-NaCl Media

Cited by 14 publications

References 36 publications

Simultaneous Leaching of Seafloor Massive Sulfides and Polymetallic Nodules

Simultaneous Leaching of Seafloor Massive Sulfides and Polymetallic Nodules

Characterisation of Mineralised Material from the Loki’s Castle Hydrothermal Vent on the Mohn’s Ridge

Conceptual 3D Modeling and Direct Block Scheduling of a Massive Seafloor Sulfide Occurrence

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