Journal articles: 'Carbonates de manganèse'

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Kamgaing, Théophile. "Précipitation de carbonates de cations divalents dans les systèmes lacustres : intérêt, état des connaissances des mécanismes et suggestions (Revue critique de la littérature)." Revue des sciences de l’eau 28, no. 2 (July 7, 2015): 81–102. http://dx.doi.org/10.7202/1032292ar.

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Les carbonates de fer, de manganèse, de calcium et de magnésium précipités en solution des lacs sont documentés. Indicateurs de climat et de variation des caractéristiques chimiques des lacs, ils sont de plus en plus recherchés dans les sédiments. Souvent incomplets, les mécanismes de leur précipitation dans la colonne d’eau du lac et dans les eaux interstitielles sont reprécisés dans cette étude. D’après la littérature, la sidérite et la rhodochrosite précipitent en milieu réducteur saturé de carbonate de fer et de carbonate de manganèse respectivement. Ces prévisions sont confirmées dans cette étude, le potentiel redox étant un paramètre déterminant pour la précipitation du carbonate de fer. Toutefois, la littérature ne décrit pas suffisamment l’origine (géochimique ou biologique) des éléments constitutifs des solides carbonatés lacustres, encore moins les phénomènes qui stabilisent ces derniers ou les rendent vulnérables (dissolution). Cette étude apporte plus de précisions à l’endogènèse de ces carbonates, l’origine de leurs éléments constitutifs étant prise en compte. Elle montre que le caractère de l’eau (agressif ou incrustant) pourrait avoir un impact considérable sur le devenir de ces carbonates. Ainsi un dégazage forcé d’un lac rendrait ses eaux incrustantes, caractère idéal pour la précipitation des carbonates, mais néfaste à la stabilité des strates qui changent de composition après précipitation d’espèces chimiques. Par conséquent, tout projet de dégazage de lac devrait prendre en considération ce paramètre (caractère de l’eau) dans sa conception, sa mise en oeuvre et son exploitation.

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de Rafélis, Marc, Maurice Renard, Laurent Emmanuel, and Christophe Durlet. "Apport de la cathodoluminescence à la connaissance de la spéciation du manganèse dans les carbonates pélagiques." Comptes Rendus de l'Académie des Sciences - Series IIA - Earth and Planetary Science 330, no. 6 (March 2000): 391–98. http://dx.doi.org/10.1016/s1251-8050(00)00148-8.

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Xu, Hengchao, Xiaotong Peng, Kaiwen Ta, Taoran Song, Mengran Du, Jiwei Li, Shun Chen, and Zhiguo Qu. "Structure and Composition of Micro-Manganese Nodules in Deep-Sea Carbonate from the Zhaoshu Plateau, North of the South China Sea." Minerals 10, no. 11 (November 15, 2020): 1016. http://dx.doi.org/10.3390/min10111016.

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The occurrence of deep-sea ferromanganese nodules and crusts on the seafloor is widespread, providing an important resource for numerous metals such as Ni, Co, and Cu. Although they have been intensively studied in the past, the formation of micro-manganese nodules within carbonate rocks has received less attention, despite the considerable amounts of manganese released from the dissolution of the calcareous framework. The micro-petrographic and geochemical characteristics of reef carbonate rocks recovered from the Zhaoshu plateau in the Xisha uplift, north of the South China Sea, were studied using optical microscopy, scanning electron microscopy, confocal Raman spectrometry, and an electron probe micro-analyzer. The carbonate rocks are composed of biogenic debris, including frameworks of coralline algae and chambers of foraminifer, both of which are suffering strong micritization. Within the calcite micrite, numerous micro-manganese nodules were identified with laminated patterns. Mineral and elemental evidence showed that the Mn oxides in the carbonates are mixed with 10 Å vernadite, 7 Å vernadite and todorokite, both of which are closely associated with the carbonate matrix. The micro-nodules were found to have high Mn/Fe ratios, enriched in Ni and Cu and depleted in Co. We infer that theses nodules are mixed type with early diagenetic growth under oxic–suboxic conditions. The re-distribution of manganite within the rocks is likely influenced by micritization of the calcareous framework. We deduce that microbial-associated reduction of manganite induces the formation of diagenetic todorokite similar to nodules buried in marine sediments.

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Rincón-Tomás, Blanca, Bahar Khonsari, Dominik Mühlen, Christian Wickbold, Nadine Schäfer, Dorothea Hause-Reitner, Michael Hoppert, and Joachim Reitner. "Manganese carbonates as possible biogenic relics in Archean settings." International Journal of Astrobiology 15, no. 3 (July 2016): 219–29. http://dx.doi.org/10.1017/s1473550416000264.

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AbstractCarbonate minerals such as dolomite, kutnahorite or rhodochrosite are frequently, but not exclusively generated by microbial processes. In recent anoxic sediments, Mn(II)carbonate minerals (e.g. rhodochrosite, kutnahorite) derive mainly from the reduction of Mn(IV) compounds by anaerobic respiration. The formation of huge manganese-rich (carbonate) deposits requires effective manganese redox cycling in an oxygenated atmosphere. However, putative anaerobic pathways such as microbial nitrate-dependent manganese oxidation, anoxygenic photosynthesis and oxidation in ultraviolet light may facilitate manganese cycling even in an early Archean environment, without the availability of oxygen. In addition, manganese carbonates precipitate by microbially induced processes without change of the oxidation state, e.g. by pH shift. Hence, there are several ways how these minerals could have been formed biogenically and deposited in Precambrian sediments. We will summarize microbially induced manganese carbonate deposition in the presence and absence of atmospheric oxygen and we will make some considerations about the biogenic deposition of manganese carbonates in early Archean settings.

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Féliers, C., L. Patria, J. Morvan, and A. Laplanche. "Le péroxyde d'hydrogène en désodorisation physico-chimique : Rôle de la composition de la solution de lavage dans le mécanisme d'action." Revue des sciences de l'eau 14, no. 1 (April 12, 2005): 3–20. http://dx.doi.org/10.7202/705405ar.

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La désodorisation physico-chimique en stations d'épuration s'effectue généralement par lavage basique oxydant pour piéger les espèces soufrées réduites telles que H2 S ou CH3 SH. L'utilisation du peroxyde d'hydrogène n'est pas encore répandue en comparaison de celle du chlore. Cette étude a été menée afin de déterminer le comportement de H2O2 en fonction de la composition de l'eau de lavage. L'influence des paramètres : concentration en métaux (fer, manganèse, cuivre et zinc), pH, [H2O2], [CO32-], [HS-] a été étudiée en utilisant un plan d'expériences. La décomposition de H2O2 et la concentration de radicaux libres ont été mesurées pour chaque expérience. En présence de métaux, un pH élevé et une forte concentration en peroxyde sont les deux paramètres principalement responsables d'une forte décomposition. Cette décomposition serait accompagnée d'une production de radicaux avec [HO°]max =10-13 M. Cette valeur mesurée de radicaux dans le milieu n'explique qu'une petite part de la décomposition de peroxyde observée. Par conséquent, la majorité de la décomposition est due à des réactions soit à la surface des oxydes, soit en solution avec les cations dissous. Le mélange de métaux et de carbonates à pH 10,5 présente un effet de synergie sur la décomposition de H2O2. Ces résultats démontrent que malgré le pouvoir oxydant des radicaux HO° formés, l'utilisation de H2O2 en désodorisation ne sera possible qu'avec l'ajout de stabilisant.

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Theingi, Mya, Ji Ma, Hui Zhang, Xiang Gao, Jian Hong Yi, and Qing Ming Chen. "Study of Structural and Electrical Transport Properties of Polycrystalline La_1-XCa_XMnO₃ (x=0.33, 0.5 and 0.9) Prepared by a Co-Precipitation Method." Advanced Materials Research 652-654 (January 2013): 576–80. http://dx.doi.org/10.4028/www.scientific.net/amr.652-654.576.

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Manganite perovskite La1-xCaxMnO3(x=0.33, 0.5 and 0.9) have been prepared by chemical co-precipitation method. Ammonium carbonate was used to coprecipitate lanthanum, calcium and manganese ions as carbonates under basic condition. This precursor on calcining at 900°C yields La-Ca-Mn-O perovskite phase. Follow by sintering at 1200°C after the powders were pressed into pellets gave La1-xCaxMnO3(LCMO) polycrystalline ceramics. The crystal phases of the resulting powders and ceramics were examined by X-ray diffraction (XRD) technique. The morphology of the powders was observed by scanning electron microscopy (SEM) and electrical transport properties of ceramics were measured by conventional four-point probe technique.

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Xu, Zhiming, Chengquan Wu, Zhengwei Zhang, Jinhong Xu, Xiyao Li, and Ziru Jin. "Separation of Fe from Mn in the Cryogenian Sedimentary Mn Deposit, South China: Insights from Ore Mineral Chemistry and S Isotopes from the Dawu Deposit." Minerals 11, no. 5 (April 23, 2021): 446. http://dx.doi.org/10.3390/min11050446.

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Manganese and Fe have similar geochemical properties in the supergene environment. Separation of Mn and Fe is an important process for the formation of high-grade sedimentary manganese deposits. Large-scale manganese carbonate deposits (total reserves of approximately 700 Mt) were formed during the interglacial of the Sturtian and Marinoan in South China. The orebodies are hosted in the black rock series at the basal Datangpo Formation of the Cryogenian period. The Fe contents in ores range from 1.15 to 7.18 wt.%, with an average of 2.80 wt.%, and the average Mn/Fe ratio is 8.9, indicating a complete separation of Mn and Fe during the formation of manganese ores. Here, we present element data of manganese carbonates and sulfur isotopes of pyrite from the Dawu deposit, Guizhou, China, aiming to investigate the separation mechanism of Mn and Fe and the ore genesis. The Fe in ores mainly occurs as carbonate (FeCO3) and pyrite (FeS2). The Mn, Ca, Mg and Fe exist in the form of isomorphic substitutions in manganese carbonate. The contents of FeCO3 in manganese carbonates are similar in different deposits, with averages of 2.6–2.8 wt.%. The whole-rock Fe and S contents have an obvious positive correlation (R = 0.69), indicating that the difference of whole-rock Fe content mainly comes from the pyrite content. The δ34SV-CDT of pyrite varies from 40.0 to 48.3‰, indicating that the pyrite formed in a restricted basin where sulfate supply was insufficient and the sulfate concentrations were extremely low. Additionally, the whole-rock Fe content is negatively correlated with the δ34S values of the whole-rock and pyrite, with correlation coefficients of −0.78 and −0.83, respectively. Two stages of separations of Mn and Fe might have occurred during the mineralization processes. The reduced seawater became oxidized gradually after the Sturtian glaciation, and Fe2+ was oxidized and precipitated before Mn2+, which resulted in the first-stage separation of Mn and Fe. The residual Mn-rich and Fe-poor seawater flowed into the restricted rift basin. Mn and Fe were then precipitated in sediments as oxyhydroxide as the seawater was oxidized. At the early stage of diagenesis, organic matter was oxidized, and manganese oxyhydroxide was reduced, forming the manganese carbonate. H2S was insufficient in the restricted basin due to the extremely low sulfate concentration. The Fe2+ was re-released due to the lack of H2S, resulting in the second-stage separation of Mn and Fe. Finally, the manganese carbonate deposit with low Fe and very high δ34S was formed in the restricted basin after the Sturtian glaciation.

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Sun, Yuedong, Jörn Peckmann, Yu Hu, Xudong Wang, Shanggui Gong, Yongbo Peng, Duofu Chen, and Dong Feng. "Formation of Tubular Carbonates within the Seabed of the Northern South China Sea." Minerals 10, no. 9 (August 29, 2020): 768. http://dx.doi.org/10.3390/min10090768.

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A remarkable exposure of tubular authigenic carbonates was found on the seafloor in the Dongsha area of the South China Sea (SCS). The tubular carbonates, around 2–3 cm in diameter and usually less than 10 cm in length, represent broken fragments of once-larger pipes that now protrude from muddy sediments. The morphology, carbon and oxygen stable isotope compositions, and trace and rare earth element contents of the carbonates were analyzed to decipher the mode of carbonate formation. The tubular carbonates exhibit a dark brown coating of iron and manganese hydrous oxides, indicating prolonged exposure to oxic bottom waters. The carbonate content of the micritic pipes falls between 12.5 and 67.3 wt.% with an average of 42.0 wt.%, suggesting formation within the sediment. This inference is supported by trace and rare earth element patterns including a moderate enrichment of middle rare earth elements. Low δ13C values (as low as −50.3‰, Vienna Pee Dee Belemnite (VPDB)) suggest that carbonate precipitation was induced by the anaerobic oxidation of methane. The unusually positive δ18O values of the carbonates (as high as +5.3‰, VPDB) are believed to reflect the destabilization of locally abundant gas hydrate. Taken together, it is suggested that pipe formation was initiated by sediment-dwelling organisms, such as crustaceans or bivalves. The burrows subsequently acted as conduits for upward fluid migration. The lithification of the sediment directly surrounding the conduits and the partial filling of the conduits with carbonate cement resulted in the formation of tubular carbonates. Turbidity currents, sediment slumps, or the vigorous emission of fluids probably induced the fragmentation of tubular carbonates within the sediment. The carbonate fragments had been further subjected to winnowing by bottom currents. This study provides insight into the interaction of megafauna burrowing with fluid migration and carbonate formation at hydrocarbon seeps, highlighting the role of bottom currents and mass wasting on the formation of fragmented tubular carbonates.

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Brusnitsyn, A. I., E. V. Starikova, M. V. Ignatova, and V. N. Kuleshov. "The Nadeiyakha Ore occurrence (Pai-Khoi, Russia): an example of ferromanganese metasediments in carbonaceous dolomitic shales." Литология и полезные ископаемые, no. 2 (March 28, 2019): 165–92. http://dx.doi.org/10.31857/s0024-497x20192165-192.

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The paper presents the results of study of metalliferous (ferromanganese and manganese) rocks at the Nadeiyakha ore occurrence (Pai-Khoi) discovered in 2010. The metalliferous deposit represents a stratiform body lying conformably in the Upper Devonian carbonaceous siliceous and clayey–carbonate–siliceous shales. The ore bed occurs 180 m below the regional Famennian manganiferous rock association in Pai-Khoi. Discovery of the Nadeiyakha ore occurrence suggests the existence of an additional age interval of Mn accumulation within the Devonian sequence of this region. The studied metalliferous rocks display structures and textures typical of the metasedimentary rocks. In terms of composition, they are divided into two varieties: (i) ferromanganese (quartz–carbonate) rocks composed of quartz, dolomite, kutnahorite, rhodochrosite, siderite, and calcite; (ii) manganiferous (quartz–rhodochrosite–silicate) rocks composed of quartz, rhodochrosite, tephroite, sonolite, and pyroxmangite. The Nadeiyakha ore occurrence is marked by the abundance of dolomite in the ferromanganese rocks and host shales. In terms of the relationship of indicator elements (Al, Ti, Fe, and Mn), ferromanganese and manganese rocks are comparable with the recent metalliferous and ore-bearing sediments. The carbon isotope composition in carbonates (δ13C from –16.4 to –7.8‰ PDB) corresponds to authigenic carbonates related to the involvement of carbon dioxide produced during the microbial decomposition of organic matter at the stage of dia- and/or catagenesis. Geological and petrographic observations show that the ferruginous and manganiferous sediments were deposited synchronously with the terrigenous–carbonate–siliceous sediments. Fe and Mn could be sourced from hydrothermal solutions or interstitial diagenetic waters. The latter version seems to be more probable. Metals were accumulated in a depression-trap characterized by a periodic stagnation of bottom waters. Such sedimentation setting promoted the formation of paragenetic association of ferruginous and manganiferous sediments with the carbonaceous sediments and fostered reductive conditions during the postsedimentary mineral formation. Calcium carbonates contained in the primary rocks were subjected to dolomitization during the dia- or catagenesis. This process was promoted by the mobilization of Mg released during the transformation of clay minerals owing to the montmorillonite–illite transition. Iron and manganese carbonates were formed during the later replacement of oxides of Mn3+, Mn4+, and Fe3+. Crystallization of manganese silicates also started at early stages of lithogenesis and terminated during the regional metamorphism of metalliferous rocks.

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Varentsov, I. M., and V. N. Kuleshov. "Rare elements — setting markers of the formation of the manganese and iron ore deposits of Kalahari and Postmasburg areas (South Africa). Communication 1. Kalahari manganese field." Литология и полезные ископаемые, no. 4 (July 9, 2019): 364–86. http://dx.doi.org/10.31857/s0024-497x20194364-386.

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In manganese ores of the Hotazel Formation (Transvaal supergroup) of the Lower Proterozoic, associated with banded ferrous silicites, high concentrations of a number of rare elements (B, Ge, W, Mo, Cr, Ni, Zn, Cd, Pb, Ag, Bi, As, Sb, Te, Se) were determined. High boron contents in oxide-carbonate ores (manganese lutites) are considered as a consequence of the concentration by chemsorbtion of this element on Mn-carbonates. It is proposed that as a result of hydrothermal transformations, a wide range of ore-forming (mainly Fe, Mn) and rare elements (including REE) was removed from the underlying andesite-basaltic hyaloclastite Ongeluk Formation In manganese ores and ferruginous silicites, typical values of cerium (Ce/Ce* 0.28–1.72) and europium (Eu/Eu* 0.57–16.31) anomalies were established, which may indicate that the initial sediments accumulated in the marginal shallow sea basin with a pronounced oxide surface water layer and close to anoxide conditions near the bottom. Metalliferous (Mn, Fe) sediments of a shallow water basin at different stages of lithogenesis were enriched with europium (positive Eu/Eu*), subjected to metasomatosis (with redistribution of manganese and the formation of manganese carbonates) and, subsequently, regional metamorphism (up to the stage of sericitic green schists).

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Neubeck, Anna, Magnus Ivarsson, Curt Broman, Jonathan Lima-Zaloumis, Wolfgang Bach, and Martin Whitehouse. "Carbon isotopic composition of Frutexites in subseafloor ultramafic rocks." Biogeochemistry 154, no. 3 (May 14, 2021): 525–36. http://dx.doi.org/10.1007/s10533-021-00806-7.

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AbstractMicrometer sized stromatolitic structures called Frutexites are features observed in samples from the deep subsurface, and hot-spring environments. These structures are comprised of fine laminations, columnar morphology, and commonly consist of iron oxides, manganese oxides, and/or carbonates. Although a biological origin is commonly invoked, few reports have shown direct evidence of their association with microbial activity. Here, we report for the first time the occurrence of subsurface manganese-dominated Frutexites preserved within carbonate veins in ultramafic rocks. To determine the biogenicity of these putative biosignatures, we analyzed their chemical and isotopic composition using Raman spectroscopy and secondary ion mass spectroscopy (SIMS). These structures were found to contain macromolecular carbon signal and have a depleted 13C/12C carbon isotopic composition of – 35.4 ± 0.50‰ relative to the entombing carbonate matrix. These observations are consistent with a biological origin for the observed Frutexites structures.

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Zhang, Bang-Lu, Chang-Le Wang, Leslie J. Robbins, Lian-Chang Zhang, Kurt O. Konhauser, Zhi-Guo Dong, Wen-Jun Li, Zi-Dong Peng, and Meng-Tian Zheng. "Petrography and Geochemistry of the Carboniferous Ortokarnash Manganese Deposit in the Western Kunlun Mountains, Xinjiang Province, China: Implications for the Depositional Environment and the Origin of Mineralization." Economic Geology 115, no. 7 (November 1, 2020): 1559–88. http://dx.doi.org/10.5382/econgeo.4729.

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Abstract The Upper Carboniferous Ortokarnash manganese ore deposit in the West Kunlun orogenic belt of the Xinjiang province in China is hosted in the Kalaatehe Formation. The latter is composed of three members: (1) the 1st Member is a volcanic breccia limestone, (2) the 2nd Member is a sandy limestone, and (3) the 3rd Member is a dark gray to black marlstone containing the manganese carbonate mineralization, which, in turn, is overlain by sandy and micritic limestone. This sequence represents a single transgression-regression cycle, with the manganese deposition occurring during the highstand systems tract. Geochemical features of the rare earth elements (REE+Y) in the Kalaatehe Formation suggest that both the manganese ore and associated rocks were generally deposited under an oxic water column with Post-Archean Australian Shale (PAAS)-normalized REE+Y patterns displaying characteristics of modern seawater (e.g., light REE depletion and negative Ce anomalies). The manganese ore is dominated by fine-grained rhodochrosite (MnCO3), dispersed in Mn-rich silicates (e.g., friedelite and chlorite), and trace quantities of alabandite (MnS) and pyrolusite (MnO2). The replacement of pyrolusite by rhodochrosite suggests that the initial manganese precipitates were Mn(IV)-oxides. Precipitation within an oxic water column is supported by shale-normalized REE+Y patterns from the carbonate ores that are characterized by large positive Ce (>3.0) anomalies, negative Y (~0.7) anomalies, low Y/Ho ratios (~20), and a lack of fractionation between the light and heavy rare earth elements ((Nd/Yb)PAAS ~0.9). The manganese carbonate ores are also 13C-depleted, further suggesting that the Mn(II) carbonates formed as a result of Mn(III/IV)-oxide reduction during burial diagenesis.

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Li, Qian Qian, Run Hua Fan, Yu Jun Bai, Chuan Bing Cheng, Gui Fang Liu, Lu Lu, and Pei Tao Xie. "Preparation of Nickel and Manganese Dioxide by Co-Precipitation and its Electrochemical Capacitive Properties." Materials Science Forum 814 (March 2015): 86–90. http://dx.doi.org/10.4028/www.scientific.net/msf.814.86.

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The precursor nickel and manganese carbonates were synthesized by co-precipitation with sodium carbonate as precipitant, and then nickel and manganese oxides were gained after calcination. The phase and morphology of the synthesized product were characterized by X-ray diffraction (XRD) and scanning electron microscope (SEM), and the electrochemical characterization was performed using cyclic voltammetry (CV), galvanostatic charge–discharge tests (GCD) and electrochemical impedance spectroscopy (EIS) in a 6mol/L KOH aqueous solution electrolyte. The result showed that the products were the mixture of nickel and manganese oxides and solid solution. nanoparticles and spherical particles were gained by controlling the molar ratio of nickel and manganese. All of the samples exhibited typical Faradic redox capacitance. The specific capacitance was different with the change of nickel and manganese molar ratio. The specific capacitance (Cs) reached 130F/g at 1A/g when the ratio was 2:1.

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Liu, Winnie, Jihua Hao, Evert J. Elzinga, Piotr Piotrowiak, Vikas Nanda, Nathan Yee, and Paul G. Falkowski. "Anoxic photogeochemical oxidation of manganese carbonate yields manganese oxide." Proceedings of the National Academy of Sciences 117, no. 37 (August 31, 2020): 22698–704. http://dx.doi.org/10.1073/pnas.2002175117.

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The oxidation states of manganese minerals in the geological record have been interpreted as proxies for the evolution of molecular oxygen in the Archean eon. Here we report that an Archean manganese mineral, rhodochrosite (MnCO3), can be photochemically oxidized by light under anoxic, abiotic conditions. Rhodochrosite has a calculated bandgap of about 5.4 eV, corresponding to light energy centering around 230 nm. Light at that wavelength would have been present on Earth’s surface in the Archean, prior to the formation of stratospheric ozone. We show experimentally that the photooxidation of rhodochrosite in suspension with light centered at 230 nm produced H2 gas and manganite (γ-MnOOH) with an apparent quantum yield of 1.37 × 10−3 moles hydrogen per moles incident photons. Our results suggest that manganese oxides could have formed abiotically on the surface in shallow waters and on continents during the Archean eon in the absence of molecular oxygen.

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Ryzhenko, B. N., M. V. Mironenko, and O. A. LImantseva. "Equilibrium and kinetic simulation of groundwater demanganation and deironing." Геохимия 64, no. 12 (December 20, 2019): 1247–60. http://dx.doi.org/10.31857/s0016-752564121247-1260.

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Analysis of chemical equilibria among iron and manganese aqueous species at various Eh-pH conditions and aqueous CO2 concentration is done. Thermodynamic and equilibrium-kinetic simulation of iron and manganese aqueous species oxidations is developed for groundwater demanganation and deironing. Numerical simulation of chemical interactions in the system groundwater-aqueous oxygen-rock minerals-aqueous carbon dioxide is shown that deironing is effective enough but aqueous manganese(II) concentration is increased. It occurs because (Fe,Mn)CO3 solubility rate is too slow and (Fe,Mn)CO3 dissolution and removal of aqueous iron species results in secondary MnCO3 formation. Using published experimental data on carbonate dissolution kinetics, iron and manganese oxidation kinetics and the critical values of rate constants of iron and manganese homogenous oxidation, iron and manganese carbonates solubility, manganese homogenous catalytical oxidation on iron hydroxide suspension are chosen. The kinetics-thermodynamics model of underground oxidation of iron and manganese by dissolved oxygen have been developed. By numerical simulation of chemical interactions in the system groundwater saturated by oxygen-stratal water-intake rock minerals shows that deironing occurs effective enough but aqueous manganese concentration increased. It happens due to aqueous manganese slow oxidation and dissolution of (Fe,Mn)CO3. Also secondary MnCO3 formation is possible due to removal of aqueous iron specis. So underground demanganation is possible if there is no (Fe,Mn)CO3 among intake rock minerals or inconvenience of water contact with it.

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Tu, Zhongbing, Xiaoping Liang, Yu Wang, and Chengbo Wu. "Removal of Phosphorus from High-Phosphorus Manganese Ores by Ammonia-Ammonium Carbonate Leaching Method." Metals 9, no. 12 (December 16, 2019): 1354. http://dx.doi.org/10.3390/met9121354.

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High-phosphorus manganese ores provide an important source of manganese, which is regarded as an irreplaceable material in the steel industry. The ammonia-ammonium carbonate leaching method was proposed for the removal of phosphorus and extracting manganese from high-phosphorus manganese ore, both effectively and environmentally. To explore the dissolution behavior of phosphorus and manganese in the ammonia-ammonium carbonate solution, the effect of the ammonia-to-ammonium carbonate concentration ratio, the leaching temperature, and the liquid-to-solid ratio on manganese extraction and dephosphorization rate were investigated. In addition, the composition of precipitated manganiferous sample, which was obtained from high-phosphorus manganese ores by ammonia-ammonium carbonate leaching process, was also studied. The results indicated that more than 99.2% phosphorus was removed and more than 83.5% of manganese was extracted by ammonia-ammonium carbonate leaching under the following conditions: ammonia to ammonium carbonate concentrations: 14:2 mol/L; liquid/solid ratio: 5:1 mL/g; leaching temperature: 25 °C; The precipitated manganiferous sample has little impurities, Mn% is 44.12%, P% is 0.02%, P/Mn = 0.00045.

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Faria, Geraldo Lúcio, Nelson Jannotti, and Fernando Gabriel da Silva Araújo. "Particle disintegration of an important Brazilian manganese lump ore." Rem: Revista Escola de Minas 67, no. 1 (March 2014): 55–60. http://dx.doi.org/10.1590/s0370-44672014000100008.

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The manganese lump ore from Morro da Mina mine is typically silicate carbonated and presents a great economic potential for the ferroalloy companies installed in Minas Gerais. However, its low manganese content, associated with the lack of knowledge about its metallurgical properties makes it difficult for large scale application. This pioneering study aimed to amply investigate this lump ore's particle disintegration. One ton of ore from the mine was homogenized and quartered. Representative samples were characterized by different techniques, such as ICP-AES, XRD, SEM, BET and OM. Aiming to characterize particle disintegration, three parameters were proposed: Cold Disintegration Index (CDI), Decrepitation Index (DI) and Heating Disintegration Index (HDI). By using these indexes, it was possible to conclude that this manganese lump ore did not present significant disintegration at room temperature. At medium temperature test, slight decrepitation occurred, and at high temperatures, intense disintegration was detected. The carbonate decomposition and porosity growth were the main responsible factors for the ore hot particle disintegration.

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Lenz, C., T. Jilbert, D. J. Conley, M. Wolthers, and C. P. Slomp. "Are recent changes in sediment manganese sequestration in the euxinic basins of the Baltic Sea linked to the expansion of hypoxia?" Biogeosciences Discussions 11, no. 6 (June 25, 2014): 9889–918. http://dx.doi.org/10.5194/bgd-11-9889-2014.

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Abstract. Expanding hypoxia in the Baltic Sea over the past century has led to anoxic and sulfidic (euxinic) deep basins that are only periodically ventilated by inflows of oxygenated waters from the North Sea. In this study, we investigate the consequences of the expanding hypoxia for manganese (Mn) burial in the Baltic Sea using a combination of pore water and sediment analyses of well-dated sediment cores from 8 locations. Diffusive fluxes of dissolved Mn from sediments to overlying waters at oxic and hypoxic sites are in line with an active release of Mn from these areas. However, this flux of Mn is only small when compared to the large pool of Mn already present in the hypoxic and anoxic water column. Our results highlight two modes of Mn carbonate formation in sediments of the deep basins. In the Gotland Deep area, Mn carbonates likely form from Mn oxides that are precipitated from the water column directly following North Sea inflows. In the Landsort Deep, in contrast, Mn carbonate and Mn sulfide layers form independent of inflow events, with pore water Mn produced in deeper layers of the sediment acting as a key Mn source. While formation of Mn enrichments in the Landsort Deep continues to the present, this does not hold for the Gotland Deep area. Here, increased euxinia, as evident from measured bottom water sulfide concentrations and elevated sediment molybdenum (Mo), goes hand in hand with a decline in sediment Mn and recent inflows of oxygenated water (since ca. 1995) are no longer consistently recorded as Mn carbonate layers. We postulate that the reduction of Mn oxides by hydrogen sulfide following inflows has become so rapid that Mn2+ is released to the water column before Mn carbonates can form. Our results have important implications for the use of Mn carbonate enrichments as a redox proxy in marine systems.

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Sharma, Renu. "HREM studies of structure, defects and phase transformation in zirconia and Mn stabilised zirconia." Proceedings, annual meeting, Electron Microscopy Society of America 48, no. 4 (August 1990): 824–25. http://dx.doi.org/10.1017/s0424820100177258.

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Zirconia is known to exist in three different structure types: monoclinic, tetragonal and cubic. Monoclinic is the room temperature form that transforms to tetragonal and finally to cubic at progressively higher temperatures. The monoclinic to tetragonal transformation is reversible, exhibits hysteresis and has been widely studied by thermal analysis, high temperature x-ray diffraction and electron diffraction. This transformation has an undesirable effect on some materials properties. The cubic form of zirconia has been stabilised with yttria, calcia, alumina and magnesia. The decomposition of zirconium carbonate and zirconium manganese carbonate to the respective oxides and their phase tranformation has been studied in situ by electron diffraction and high resolution electron microscopy (HREM) and the results are reported here.The carbonates used in these studies were precipitated from their aqueous solution. Thin crystal fragment were dispersed on holey carbon grids using a suspension in ethanol. A JE0L 4000EX microscope, with double tilt goniometer and on-line Digital MicroVAX II image-analysis system, operating at 400KV, was used for HREM studies.

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Wu, Yan, Bin Shi, Huan Liang, Wen Ge, Chun Jie Yan, and Xiang Yang. "Magnetic Properties of Low Grade Manganese Carbonate Ore." Applied Mechanics and Materials 664 (October 2014): 38–42. http://dx.doi.org/10.4028/www.scientific.net/amm.664.38.

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Rapid reduction roasting of low grade manganese carbonate ore by coal and biomass fuels from Hunan, China was investigated. Magnetic separation behaviors and magnetic properties of raw manganese ore and roasted manganese ores were analyzed. After reduction by coal and biomass fuels, the manganese ores demonstrate a new Mn-Fe oxide phase, showing obvious mixed magnetic behaviors of ferromagnet and paramagnet, and the magnetic susceptibilities of roasting ores rapidly increase to almost two orders of magnitude in comparison of the raw ores. The results show that magnetizing roasting technology could enhanced the magnetic properties of the manganese ores about two orders of magnitude higher than raw manganese ore at low roasting temperature. Thereby, we deduce that the weak magnetic separation combined with high magnetic separation could be adequate for roasted manganese ore to satisfy the requirement of electrolytic manganese industry. Application of biomass in manganese ore roasting process is promising to the effective use of biomass and for decreasing the consumption of fossil fuels in the manganese industry.

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21

SANTOS, M. C. D., A. R. MERMUT, D. W. ANDERSON, and R. J. ST. ARNAUD. "MICROMORPHOLOGY OF THREE GRAY LUVISOLS IN EAST-CENTRAL SASKATCHEWAN." Canadian Journal of Soil Science 65, no. 4 (November 1, 1985): 717–26. http://dx.doi.org/10.4141/cjss85-077.

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Micromorphology of three Gray Luvisolic soils under Boreal Forests occurring on late Wisconsinan age glacial till were studied. Profiles 1 and 2 occurred on loam with 8–10% carbonates; Profile 3 on clay loam till with 58% carbonates. The presence of various fecal pellets shows the importance of soil fauna in the decomposition of litter and the formation of aggregates in organic horizons. Aggrotubules and fecal pellets in the lower part of the profiles testified to the presence of biological activity even at depth. Several types of banded fabrics and iron-manganese nodules were observed, and are thought to result from temporary saturated conditions of the Ae horizons. Ferri-argillans occur as both illuviation (due to lessivage) and in situ weathering cutans. The weakest ferriargillans were found in the thickest profile. The most birefringent ferriargillans with strong continuous orientation and the most abundant iron-manganese nodules were found in Profile 3 which had the thinnest solum. This indicates that high carbonate content reduces the depth of solum, but not intensity of soil-forming processes. Considerable amount of weathering of the primary minerals, particularly sand-sized micas and feldspars in the C horizons was attributed to ancient chemical weathering. Analyses indicated the physical breakdown of sand particles to silt in the Ae horizons. Neocalcitans were observable in the relatively thicker Profiles 1 and 2 and calcans were specific to Profile 3 with extremely calcareous, dominantly dolomitic parent material. Key words: Luvisols, Boreal Forest soil, micromorphology, nodules, cutans, faunal activity

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Dasgupta, Somnath, P. K. Bhattacharya, H. Banerjee, M. Fukuoka, N. Majumdar, and Supriya Roy. "Calderite-rich garnets from metamorphosed manganese silicate rocks of the Sausar Group, India, and their derivation." Mineralogical Magazine 51, no. 362 (October 1987): 577–83. http://dx.doi.org/10.1180/minmag.1987.051.362.12.

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AbstractManganiferous garnets occur in metamorphosed Mn silicate-oxide and silicate-carbonate-oxide rocks of the Sausar Group, India. The garnets of the carbonatic rock show maximum calderite content (∼50 mole%). Increased Ca content in the bulk has been observed to be sympathetically related to the concentration of calderite, rather than the expected andradite component of the garnets. This is the consequence of the preferential partitioning of Ca in coexisting pyroxmangite and/or carbonate. Petrochemical characteristics of the diverse assemblages in response to the physical conditions of metamorphism show that the calderite solubility in manganiferous garnet is not only a function of pressure. Such characteristics only indicate that the mobile components in the bulk influenced the mineralogy of the assemblages at the ambient physical conditions of metamorphism, and this in turn controlled the calderite solubility in garnet.

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23

Sanz, A., MT Garcia-Gonzalez, C. Vizcayno, and R. Rodriguez. "Iron-manganese nodules in a semi-arid environment." Soil Research 34, no. 5 (1996): 623. http://dx.doi.org/10.1071/sr9960623.

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Relationships between the chemical, mineralogical, and morphological characteristics and the formation mechanisms of some iron-manganese (Fe–Mn) accumulations were investigated. The nodules studied were from a poorly drained soil profile with a high calcium carbonate content, located in a semi-arid environment. Three types of nodules, Fe-rich (typic or annular morphology) Mn-rich (aggregate morphology), and Fe–Mn-rich (compound morphology), were encountered, all of which were formed in situ. The nodules were found to contain goethite, and a low proportion of poorly crystallised Fe oxides and Mn oxides (birnessite and vernadite). However, they contained no siderite or rhodochrosite, both highly frequent occurrences in carbonatic systems with redox fluctuations. In the formation of compound nodules, Fe- and Mn-rich nodules may act as nucleating structures for subsequent accumulations in the form of coatings and/or matrix impregnations.

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Thiyagarajan, Chitdeshwari, R. W. Bell, J. Anderson, and I. R. Phillips. "Plant-available manganese in bauxite residue sand amended with compost and residue mud." Soil Research 50, no. 5 (2012): 416. http://dx.doi.org/10.1071/sr11342.

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Manganese (Mn) deficiency has been a constraint for revegetation on bauxite residue sand and there is still no effective strategy to remedy this problem. The effect of addition of organic amendments (piggery waste, biosolids, and commercial compost) and mineral amendments (unamended, seawater-neutralised residue mud, and carbonated bauxite residue mud) on Mn forms and availability in residue sand was studied. Incubation of residue sand with organic amendments (applied at rates of 0, 10, and 50 t/ha) over a 30-day period found little change in DTPA-extractable Mn concentrations, which remained below the critical level of 1 mg/kg. The DTPA-extractable Mn concentrations were comparable to those in the exchangeable fraction (DTPA-Mn = 0.931 × Exch-Mn + 0.358, r2 = 0.84) and, therefore, may provide an estimation of plant-available Mn. The highest Mn concentrations were consistently associated with the carbonate fraction, suggesting that Mn was either retained by surface adsorption reactions and/or co-precipitated with calcium carbonate. The addition of residue mud amendments generally reduced DTPA-extractable Mn, probably through adsorption by hydrous Fe and Al oxides. Leaching did not cause significant (P > 0.05) movement of Mn in residue sand columns, possibly due to the alkaline pH and specific adsorption reactions. Given the difficulty of increasing plant-available Mn by organic amendments, residue mud additions, leaching, and/or fertilisers, overcoming Mn deficiency in vegetation on bauxite residue sand may depend on using Mn-efficient species that are able to efficiently extract Mn associated with carbonate and Fe/Al oxyhydroxide fractions.

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Xia, Yanfeng, Zhe Qiang, Byeongdu Lee, Matthew L. Becker, and Bryan D. Vogt. "Solid state microwave synthesis of highly crystalline ordered mesoporous hausmannite Mn3O4films." CrystEngComm 19, no. 30 (2017): 4294–303. http://dx.doi.org/10.1039/c7ce00900c.

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Microwave calcination of ordered micelle templated manganese carbonate films leads to highly crystalline, ordered mesoporous manganese oxide, while similar temperatures in a furnace lead to disordered, amorphous manganese oxide.

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Rychagov, S. N., E. I. Sandimirova, M. S. Chernov, O. V. Kravchenko, and E. V. Kartasheva. "The Composition, Structure, and Origin of Carbonate Concretions Sampled in the South Kambalnyi Central Thermal Field, Kamchatka." Journal of Volcanology and Seismology 15, no. 4 (July 2021): 258–72. http://dx.doi.org/10.1134/s0742046321040059.

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Abstract Carbonate concretions are formed at the base of a sequence of hydrothermal clay in the South Kambalnyi Central Thermal Field situated in the southern part of the Kambalnyi volcanic mountain range, Kamchatka. The concretions have complex chemical and mineral compositions: apart from aragonite which is the main component of each layer, the chemical compounds identified there include oxides of iron and silicon, sulfates of calcium and barium, sulfides of iron and other metals, carbonates of iron and manganese, siliceous ferromanganese formations, nitrogen compounds, and phosphates of calcium and rare metals. The concretions have diverse structures and textures that indicate a multiphase character of formation for these mineral aggregates. It is thought that their formation was due to the discharge of deep-seated alkaline metalliferous solutions in a zone of rock argillization of the South Kambalnyi Central Thermal Field.

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Scarpelli, Wilson, and Élio Hiromi Horikava. "Gold, iron and manganese in central Amapá, Brazil." Brazilian Journal of Geology 47, no. 4 (December 2017): 703–21. http://dx.doi.org/10.1590/2317-4889201720170114.

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ABSTRACT: Greenstone belts with deposits of gold, iron and manganese are common in the Paleoproterozoic Maroni-Itacaiunas Tectonic Province of the Guiana Shield. In Brazil, in the State of Amapá and northwest of Pará, they are represented by the Vila Nova Group, constituted by a basal unit of metabasalts, covered by metasediments of clastic and chemical origin. The basal metasediments, the Serra do Navio Formation, are made of a cyclothem with lenses of manganese marbles at the top of each cycle. Under the intense weathering of the Amazon, these lenses were oxidized to large deposits of high-grade manganese oxides. The exploitation of these oxides left behind the manganese carbonates and low-grade oxides. The overlaying Serra da Canga Formation presents a calcium and magnesium domain grading to an iron domain with banded silicate and oxide iron formations, mined for iron ores. Overlapping structures and superposed metamorphic crystallizations indicate two phases of dynamothermal metamorphism, the first one with axis to north-northeast and the second one to northwest, with an intermediate phase of thermal metamorphism related to syntectonic granitic intrusions. Shears oriented north-south, possibly formed during the first dynamothermal metamorphism and reactivated in the second, are ideal sites for hydrothermalism and gold mineralization, which is greater when occurs in iron formation and carbonate-bearing rocks, as it happened at the Tucano mine. Layered mafic-ultramafic intrusions in the greenstones represent a potential for chromite and platinum group elements. Pegmatites are source of cassiterite and tantalite exploited from alluvial deposits.

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Lenz, C., T. Jilbert, D. J. Conley, M. Wolthers, and C. P. Slomp. "Are recent changes in sediment manganese sequestration in the euxinic basins of the Baltic Sea linked to the expansion of hypoxia?" Biogeosciences 12, no. 16 (August 19, 2015): 4875–94. http://dx.doi.org/10.5194/bg-12-4875-2015.

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Abstract. Expanding hypoxia in the Baltic Sea over the past century has led to the development of anoxic and sulfidic (euxinic) deep basins that are only periodically ventilated by inflows of oxygenated waters from the North Sea. In this study, we investigate the potential consequences of the expanding hypoxia for manganese (Mn) burial in the Baltic Sea using a combination of pore water and sediment analyses of dated sediment cores from eight locations. Diffusive fluxes of dissolved Mn from sediments to overlying waters at oxic, hypoxic and euxinic sites are consistent with an active release of Mn from these areas. Although the present-day fluxes are significant (ranging up to ca. 240 μmol m−2 d−1), comparison to published water column data suggests that the current benthic release of Mn is small when compared to the large pool of Mn already present in the hypoxic and anoxic water column. Our results highlight two modes of Mn carbonate formation in sediments of the deep basins. In the Gotland Deep area, Mn carbonates likely form from Mn oxides that are precipitated from the water column directly following North Sea inflows. In the Landsort Deep, in contrast, Mn carbonate and Mn sulfide layers appear to form independently of inflow events, and are possibly related to the much larger and continuous input of Mn oxides linked to sediment focusing. Whereas Mn-enriched sediments continue to accumulate in the Landsort Deep, this does not hold for the Gotland Deep area. Here, a recent increase in euxinia, as evident from measured bottom water sulfide concentrations and elevated sediment molybdenum (Mo), coincides with a decline in sediment Mn content. Sediment analyses also reveal that recent inflows of oxygenated water (since ca. 1995) are no longer consistently recorded as Mn carbonate layers. Our data suggest that eutrophication has not only led to a recent rise in sulfate reduction rates but also to a decline in reactive Fe input to these basins. We hypothesize that these factors have jointly led to higher sulfide availability near the sediment–water interface after inflow events. As a consequence, the Mn oxides may be reductively dissolved more rapidly than in the past and Mn carbonates may no longer form. Using a simple diagenetic model for Mn dynamics in the surface sediment, we demonstrate that an enhancement of the rate of reduction of Mn oxides is consistent with such a scenario. Our results have important implications for the use of Mn carbonate enrichments as a redox proxy in marine systems.

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Lu, Jianming, David Dreisinger, and Thomas Glück. "Electrolytic manganese metal production from manganese carbonate precipitate." Hydrometallurgy 161 (May 2016): 45–53. http://dx.doi.org/10.1016/j.hydromet.2016.01.010.

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30

Yang, Yibo, Xiaomin Fang, Erwin Appel, Albert Galy, Minghui Li, and Weilin Zhang. "Late Pliocene–Quaternary evolution of redox conditions in the western Qaidam paleolake (NE Tibetan Plateau) deduced from Mn geochemistry in the drilling core SG-1." Quaternary Research 80, no. 3 (November 2013): 586–95. http://dx.doi.org/10.1016/j.yqres.2013.07.007.

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Manganese (Mn) in lake sediments reacts strongly to changes of redox conditions. This study analyzed Mn concentrations in oxides, carbonates, and bulk phases of the calcareous lacustrine sediments of a 938.5-m-long core (SG-1) taken from the western Qaidam Basin, well dated from 2.77 Ma to 0.1 Ma. Comparisons of extractions from diluted hydrochloric acid, acetic acid and citrate"bicarbonate"dithionite demonstrate that variations of Mn concentrations from acetic acid leaching (MnHOAc) are mostly responsible for Mn (II) fluctuations in the carbonate phase. Taking into account the relevant processes during weathering, transportation, deposition and post-deposition of Mn-bearing rocks, we conclude that Mn input from catchment weathering and paleolake redox condition provide the primary controls on variations in the Mn records of carbonate and oxide phases. We propose MnHOAc as a new sensitive indicator of paleolake redox evolution and catchment-scale climate change. The MnHOAc variations show a long-term upward decreasing trend, indicating a long-term decrease of Mn input from catchment weathering associated with increasing oxygen content in the paleolake bottom water. The great similarities of the MnHOAc record with other regional and global records suggest that paleolake redox changes and climatic drying in the Qaidam Basin may be largely related to global cooling.

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Sun, Da, Mao Lin Li, Can Hua Li, Rui Cui, and Xia Yu Zheng. "A Green Enriching Process of Mn from Low Grade Ore of Manganese Carbonate." Applied Mechanics and Materials 644-650 (September 2014): 5427–30. http://dx.doi.org/10.4028/www.scientific.net/amm.644-650.5427.

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The ammonium salt roasting method is proposed to enrich and recover Mn from low grade ore of manganese carbonate. It included a process of mixing the ore with NH4Cl by ball milling, roasting this mixed ore in pipe stove at 450°Cfor one hour and leaching the calcine with hot water to obtain MnCl2solution. Further, manganese is precipitated by NH3·H2Oand CO2released from roasting process, washing and drying to get concentrated manganese ore. The NH4Cl obtained by vaporizing the filtrate solution can be reused for the ammonium salt roasting process. The result indicates that Mn recovery rate can be reached to be more than 90%. This method is considered to be a green chemistry process to enrich and recover Mn from low grade ore of manganese carbonate.

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Zhang, Yuanzhong, Sarang M. Bhaway, Yi Wang, Kevin A. Cavicchi, Matthew L. Becker, and Bryan D. Vogt. "Rapid (<3 min) microwave synthesis of block copolymer templated ordered mesoporous metal oxide and carbonate films using nitrate–citric acid systems." Chemical Communications 51, no. 24 (2015): 4997–5000. http://dx.doi.org/10.1039/c4cc09808k.

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Lyu, Luyang, Li Xiao, Juntao Lu, and Lin Zhuang. "Manganese carbonate as active material in potassium carbonate electrolyte." Chemical Physics Letters 738 (January 2020): 136899. http://dx.doi.org/10.1016/j.cplett.2019.136899.

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34

Kotler, J. M., R. C. Quinn, B. H. Foing, Z. Martins, and P. Ehrenfreund. "Analysis of mineral matrices of planetary soil analogues from the Utah Desert." International Journal of Astrobiology 10, no. 3 (March 11, 2011): 221–29. http://dx.doi.org/10.1017/s1473550411000103.

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AbstractPhyllosilicate minerals and hydrated sulphate minerals have been positively identified on the surface of Mars. Studies conducted on Earth indicate that micro-organisms influence various geochemical and mineralogical transitions for the sulphate and phyllosilicate minerals. These minerals in turn provide key nutrients to micro-organisms and influence microbial ecology. Therefore, the presence of these minerals in astrobiology studies of Earth–Mars analogue environments could help scientists better understand the types and potential abundance of micro-organisms and/or biosignatures that may be encountered on Mars. Bulk X-ray diffraction of samples collected during the EuroGeoMars 2009 campaign from the Mancos Shale, the Morrison and the Dakota formations near the Mars Desert Research Station in Utah show variable but common sedimentary mineralogy with all samples containing quantities of hydrated sulphate minerals and/or phyllosilicates. Analysis of the clay fractions indicate that the phyllosilicates are interstratified illite–smectites with all samples showing marked changes in the diffraction pattern after ethylene glycol treatment and the characteristic appearance of a solvated peak at ∼17 Å. The smectite phases were identified as montmorillonite and nontronite using a combination of the X-ray diffraction data and Fourier–Transform Infrared Spectroscopy. The most common sulphate mineral in the samples is hydrated calcium sulphate (gypsum), although one sample contained detectable amounts of strontium sulphate (celestine). Carbonates detected in the samples are variable in composition and include pure calcium carbonate (calcite), magnesium-bearing calcium carbonate (dolomite), magnesium, iron and manganese-bearing calcium carbonate (ankerite) and iron carbonate (siderite). The results of these analyses when combined with organic extractions and biological analysis should help astrobiologists and planetary geologists better understand the potential relationships between mineralogy and microbiology for planetary missions.

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Huggett, Jennifer. "Petrology and diagenesis of Palaeogene clays from Ølst and Ålbækhoved, Denmark." Bulletin of the Geological Society of Denmark 40 (December 30, 1993): 256–71. http://dx.doi.org/10.37570/bgsd-1993-40-11.

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The petrology and diagenesis of Paleocene and Eocene clays from 01st and Albrekhoved in northern Jutland, Denmark has been investigated using backscattered electron microscopy and XRD techniques. The Holmehus, 01st, Rpsnres and Lillebrelt Forma- tions were sampled at both localities, whilst at 01st, the Spvind Marl was also sampled. These sediments are extremely fine grained, smectite-rich, vari-coloured claystones with ash horizons in several formations. Smectite and carbonate minerals are the principal authigenic phases. Smectite is inferred to have formed as a result of alteration of volcanic glass, though it is unclear how much of the smectite is detrital. Three manganese bearing carbonate cements have been identified in all Formations sampled at both localities except the Holmehus Formation. These cements are manganoan calcite, calcian rhodochrosite and manganoan siderite. All occur as equant to subequant rhombs, up to 15 µm across, but typically 2-5 µm. Calcian rhodochrosite is present as overgrowths on rounded clay-size particles of high Mg (20%) calcite, which are either detrital grains or corroded authigenic cement. It also occurs as overgrowths on equant rhombs of earlier formed manganoan calcite. The manganoan siderite occurs as relatively large crystals (20 µm) scattered through the clay matrix and as concretions. Calcite cement is present in the Lillebrelt and 01st Formations. Quantitatively it is not as important as the more unusual Mn-bearing calcium carbonates.

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Mammadova, Aygul A., Sevinj N. Osmanova, Sabira A. Agayeva, Aydar A. Mejidov, and Imamaddin R. Amiraslanov. "Hydrothermal redox synthesis of cobalt and manganese spinels using metal nitrates." Butlerov Communications 60, no. 10 (October 31, 2019): 116–23. http://dx.doi.org/10.37952/roi-jbc-01/19-60-10-116.

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The hydrothermal reduction of cobalt, manganese and lithium nitrates with ethylene glycol was studied in the temperature range 100-270 оС in order to obtain nanostructured spinels. The phase composition, particle sizes of the reaction products, and their morphology studied by using IR spectroscopy, X-ray diffractometry, and scanning electron microscopy. We found that the nature of the reaction product of manganese and cobalt nitrates with ethylene glycol (EG) depends on the reaction temperature, the ratio of metal nitrate: ethylene glycol and reaction time. In excess of the reducing agent at temperatures up to 140 оС, observed the formation of metal oxalates. The main product of hydrothermal reduction of manganese nitrate with ethylene glycol at temperatures of 150 оC and 180 оC is manganese oxide Mn3O4 (Hausmanite). At 200 оС obtained the mixture of manganese oxide (Mn3O4) and carbonate (MnCO3). In accordance with the data of X-ray phase analysis at 220 оС and 240 оС, the only reaction product in both cases is manganese carbonate. It was obtained two types of structures on electron-microscopic images of the non-calcined sample at 200 оC: needle-shaped and spherical clusters. It can be assumed that these structures belong to the phases Mn3O4 (Hausmanite) and manganese carbonate MnCO3, respectively. When reduced cobalt nitrate with ethylene glycol in the temperature range 120-220 оC, gives a main amorphous phase, and on X-ray diffraction patterns are observed weak reflections corresponding to cobalt oxide Co3O4. It was shown that upon calcination (at 750 оС) of the samples during the reduction of the mixture of cobalt and manganese nitrates, was obtained the spinel phase of the composition (Co,Mn)(Co,Mn)2O4. In a similar way were obtained Li2CoMn3O8 and LiCoO2 phases (with average particle sizes of 42 nm and 30 nm), which can be used as cathodes in lithium batteries.

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Moerbeck-Filho, Pio, Suelen C. Sartoretto, Marcelo J. Uzeda, Maurício Barreto, Alena Medrado, Adriana Alves, and Mônica D. Calasans-Maia. "Evaluation of the In Vivo Biocompatibility of Amorphous Calcium Phosphate-Containing Metals." Journal of Functional Biomaterials 11, no. 2 (June 23, 2020): 45. http://dx.doi.org/10.3390/jfb11020045.

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Among the biomaterials based on calcium phosphate, hydroxyapatite has been widely used due to its biocompatibility and osteoconduction. The substitution of the phosphate group by the carbonate group associated with the absence of heat treatment and low synthesis temperature leads to the formation of carbonated hydroxyapatite (CHA). The association of CHA with other metals (strontium, zinc, magnesium, iron, and manganese) produces amorphous calcium phosphate-containing metals (ACPMetals), which can optimize their properties and mimic biological apatite. This study aimed to evaluate the biocompatibility and biodegradation of ACPMetals in mice subcutaneous tissue. The materials were physicochemically characterized with Fourier Transform InfraRed (FTIR), X-Ray Diffraction (XRD), and Atomic Absorption Spectrometry (AAS). Balb-C mice (n = 45) were randomly divided into three groups: carbonated hydroxyapatite, CHA (n = 15), ACPMetals (n = 15), and without implantation of material (SHAM, n = 15). The groups were subdivided into three experimental periods (1, 3, and 9 weeks). The samples were processed histologically for descriptive and semiquantitative evaluation of the biological effect of biomaterials according to ISO 10993-6:2016. The ACPMetals group was partially biodegradable; however, it presented a severe irritating reaction after 1 and 3 weeks and moderately irritating after nine weeks. Future studies with other concentrations and other metals should be carried out to mimic biological apatite.

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Birch, W. D. "Zinc-manganese carbonates from Broken Hill, New South Wales." Mineralogical Magazine 50, no. 355 (March 1986): 49–53. http://dx.doi.org/10.1180/minmag.1986.050.355.07.

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AbstractSpecimens of honey-brown to pinkish-brown globular carbonates encrusting concretionary goethite–coronadite from the oxidized zone at Broken Hill, New South Wales, have compositions in the rhodochrosite–smithsonite series. This may be the first extensive natural occurrence of this solid-solution series. Growth of the carbonates occurred in zones which have near uniform composition. The ratio MnCO3/(MnCO3 + ZnCO3) for each zone bears a linear relationship to the measured d spacing for the 104 X-ray reflections. Because cerussite is the only other mineral associated with the Zn-Mn carbonates and because of an absence of detailed locality information, the paragenetic significance of these minerals cannot be determined. The solutions depositing them may have been derived from the near-surface equivalents of the Zinc Lode horizons.

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Marzec, Michał, Agata Pieńko, Magdalena Gizińska-Górna, Aneta Pytka, Krzysztof Jóźwiakowski, Bożena Sosnowska, Agnieszka Kamińska, and Agnieszka Listosz. "The use of carbonate-silica rock (opoka) to remove iron, manganese and indicator bacteria from groundwater." Journal of Water and Land Development 34, no. 1 (September 26, 2017): 197–204. http://dx.doi.org/10.1515/jwld-2017-0054.

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Abstract The study investigated the efficiency of removal of iron, manganese and indicator bacteria from potable groundwater by using carbonate-silica rock (opoka). The tests were performed in a laboratory in three filter columns supplied with water containing increased concentrations of iron and manganese. Two of the columns were filled with carbonate-silica rock with particle sizes of 2-5 mm; retention time for water in the columns was set at 1 h and 2 h. A third column was filled with 1-2 mm rock particles, with hydraulic retention time set at 1 h. High removal efficiencies were determined for iron, manganese and coliform bacteria and low removal efficiencies for psychro- and mesophilic bacteria. An increase in the alkalinity of the investigated water was also observed.

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Koroleva, L. F., L. P. Larionov, and M. N. Dobrinskaya. "Implants and bone technology with the use of doped calcium carbonate phosphates." Diagnostics, Resource and Mechanics of materials and structures, no. 6 (December 2020): 54–61. http://dx.doi.org/10.17804/2410-9908.2020.6.054-061.

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The possibility of obtaining an alloplastic biomaterial for the implant based on doped calcium carbonate-phosphates and polycaprolactone is studied. Nanocrystalline calcium carbonate-phosphate doped with cations of iron, magnesium, potassium, zinc, manganese, and silicon intended for bone repair by drug delivery is investigated. Histological studies have revealed that samples after 60 days in a living organism are covered by a connective tissue capsule. The formation of blood vessels and nerve endings is observed in the capsule.

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Liang, Huan, Feng Zhou, Ze Ying Wu, Chun Jie Yan, and Wen Jun Luo. "Surface Characteristics and Flotation Behaviour of Low-Grade Manganese Ore." Advanced Materials Research 962-965 (June 2014): 361–69. http://dx.doi.org/10.4028/www.scientific.net/amr.962-965.361.

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Evaluation possibility of low grade manganese mineral from Hunan by froth flotation technique was investigated. Manganese mineral sample was characterized with mineralogical analysis, XRD, and SEM studies for its mineral content and surface characteristics. XRD analysis showed that the gangue contents of manganese minerals are constituted mainly by dolomite as a carbonate mineral, quartz and feldspar. SEM indicated that existence of rhodochrosite, which mainly fills in the dolomite minerals. The influences of important factors on manganese mineral flotation are investigated. The size of grind, pulp pH, dosages of depressant and collector are essential to the effective recovery of rhodochrosite in manganese mineral flotation.

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42

Nikolenko, Nikolai V., and Irina M. Shapovalova. "Surface Properties of Manganese(II) Carbonate." Adsorption Science & Technology 20, no. 6 (July 2002): 541–47. http://dx.doi.org/10.1260/026361702321039465.

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The energies of unoccupied and occupied orbitals have been used as correlation parameters between the electronic and adsorptive properties of organic molecules. A model describing the chemisorption of organic compounds on MnCO3 was proposed. This involves three types of interaction: 1-, 2- and 3-electron donor–acceptor interaction between adsorbent and adsorbate frontier orbitals.

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43

Ensing,, Jaap G. "Bazooka: Cocaine-Base and Manganese Carbonate." Journal of Analytical Toxicology 9, no. 1 (January 1, 1985): 45–46. http://dx.doi.org/10.1093/jat/9.1.45.

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44

Huang, Tinglin, Xin Cao, Gang Wen, and Yingming Guo. "The study on chemical adsorption of dissolved oxygen on naturally formed co-oxides filter film in aqueous solution: combined characterization of XPS and TPD." Water Supply 15, no. 2 (December 9, 2014): 411–20. http://dx.doi.org/10.2166/ws.2014.130.

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The chemical adsorption of dissolved oxygen (DO) by co-oxide filter film-coated sands, formed through the filtration of ground water containing high concentrations of ammonia, manganese and iron, were studied. The results showed that the filter film consisted of silicates, carbonates, manganese and iron oxides and was constructed in a three-layer porous structure. The specific area of film-coated sands was 6.5 m2/g. The chemical adsorption sites of DO are composed of silicates, iron and manganese atoms, and the adsorption was a weak chemical effect. The O2− is the adsorbed species of DO.

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45

Black, J. R., C. B. Ammerman, and P. R. Henry. "Effects of High Dietary Manganese as Manganese Oxide or Manganese Carbonate in Sheep2." Journal of Animal Science 60, no. 3 (March 1, 1985): 861–66. http://dx.doi.org/10.2527/jas1985.603861x.

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46

Xu, Long Jun, Xing Min Wang, Hong Chong Chen, and Cheng Lun Liu. "Mn Forms and Environmental Impact of Electrolytic Manganese Residue." Advanced Materials Research 183-185 (January 2011): 570–74. http://dx.doi.org/10.4028/www.scientific.net/amr.183-185.570.

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Mn Forms and the effect on environment of electrolytic manganese residue (EMR) in Chongqing have been investigated through water extracting and sulpharic acid leaching. The ways of comprehensive utilization on EMR has been discussed in this research. The results show that the forms of Mn in EMR are chiefly water soluble Mn (II), the manganese carbonate and manganese dioxide. The groundwater pollution and the eco-environment damage will present if the EMR is randomly stacked and thrown. Having appropriate methods, the EMR may be used as recovery manganese (e.g. manganese sulfate and producing Fe-Mn bimetal oxide). The second residue from EMR can prepare water disposal agent.

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47

Wu, Wei, Peng Wang, Lu Lin, and Shi-fan Dai. "Manganese Ore Decomposition and Carbon Reduction in Steelmaking." High Temperature Materials and Processes 37, no. 8 (August 28, 2018): 741–47. http://dx.doi.org/10.1515/htmp-2017-0042.

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AbstractTo improve the direct alloying of manganese ore in steelmaking, the decomposition and carbon reduction of manganese ore was studied using a differential thermal analyzer and resistance furnace. The remaining material after manganese ore decomposition at 1,600 °C was a mixture of 43 % MnO, 40 % MnSiO3 and FeO, and 17 % MnSiO3. The remaining material after the carbon reduction of the manganese ore was a mixture of metal (30.8 % Mn7C3 and 16.1 % FeC3) and slag (2.5 % FeO, 5.1 % SiO2, and 18.8 % MnO). The high-temperature (1,200 ℃) decomposition and reduction of manganese ore produce manganese carbonate, manganese dioxide, and manganese salicylate sesquioxide. However, because it is not easy to decompose the manganese silicate in the manganese ore, the proportion of ore being reduced by carbon is small. Therefore, the increase of the manganese reduction of manganese silicate is critical to the direct alloying of manganese ore. Adding calcium oxide or magnesium oxide to the manganese ore improves the reduction of manganese ore, whereas adding slag from the initial stage or endpoint of the converter process has little effect on the manganese ore reduction.

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Kaithal, Akash, Markus Hölscher, and Walter Leitner. "Catalytic Hydrogenation of Cyclic Carbonates using Manganese Complexes." Angewandte Chemie 130, no. 41 (September 12, 2018): 13637–41. http://dx.doi.org/10.1002/ange.201808676.

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Kaithal, Akash, Markus Hölscher, and Walter Leitner. "Catalytic Hydrogenation of Cyclic Carbonates using Manganese Complexes." Angewandte Chemie International Edition 57, no. 41 (September 12, 2018): 13449–53. http://dx.doi.org/10.1002/anie.201808676.

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Hirose, Shoji, Takayuki Kodera, and Takashi Ogihara. "Synthesis and Electrochemical Properties of Al Doped Lithium Manganate Powders by Spray Pyrolysis Using Carbonate Aqueous Solution." Key Engineering Materials 485 (July 2011): 111–14. http://dx.doi.org/10.4028/www.scientific.net/kem.485.111.

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Al doped LiMn2O4 powders were prepared by spray pyrolysis using the aqueous solution of manganese carbonate. The aqueous solution, in which manganese carbonate was uniformly dispersed by a surfactant, was used as the starting solution. Al2O3 nanopowders, Al(OH)3 and Al(NO3)3·9H2O were used as the doping agent of Al. A scanning electron microscope photograph showed that Al doped LiMn2O4 powders had spherical morphology with broad particle size distribution. X-ray diffraction revealed that crystal phase of all samples were good agreement with spinel phase. The rechargeable capacity of Al doped LiMn2O4 cathode was about 110 mAh/g at 1 C regardless of doping agent. 75% of initial discharge capacity was maintained after 100 cycles

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Journal articles on the topic 'Carbonates de manganèse'

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