Academic literature on the topic 'Carbonates de manganèse'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the lists of relevant articles, books, theses, conference reports, and other scholarly sources on the topic 'Carbonates de manganèse.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Journal articles on the topic "Carbonates de manganèse"
1
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.
Full textAbstract:
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.
2
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.
Full text
3
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.
Full textAbstract:
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.
4
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.
Full textAbstract:
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.
5
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.
Full textAbstract:
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.
6
Theingi, Mya, Ji Ma, Hui Zhang, Xiang Gao, Jian Hong Yi, and Qing Ming Chen. "Study of Structural and Electrical Transport Properties of Polycrystalline La1-XCaXMnO3 (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.
Full textAbstract:
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.
7
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.
Full textAbstract:
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.
8
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.
Full textAbstract:
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.
9
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.
Full textAbstract:
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.
10
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.
Full textAbstract:
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).
Dissertations / Theses on the topic "Carbonates de manganèse"
1
Pambo, Florent. "Conditions de formation des carbonates de manganèse protézoi͏̈ques et analyse minéralogique et géochimique des minerais à bioxydes de manganèse associés dans le gisement de Moanda (Sud-Est, Gabon)." Dijon, 2004. http://www.theses.fr/2004DIJOS004.
Full text
2
Dubois, Manon. "Environnement de dépôt et processus de formation des carbonates de manganèse dans les black shales paléoprotérozoiques du Bassin de Franceville (2.1 Ga ; Gabon)." Thesis, Montpellier, 2017. http://www.theses.fr/2017MONTT082.
Full textAbstract:
Le Bassin de Franceville situé au SE du Gabon présente une série de black shales (Formation FB) d'âge Paléoprotérozoïque (2.1 Ga) surmontant les grès de la Formation FA. Ce bassin peu déformé et non métamorphique représente une archive exceptionnelle des processus de dépôt de cette période de l’histoire de la Terre où la vie commence à se développer. En particulier, la Formation FB contient le protore d'un gisement mondial d'oxydes de manganèse exploité par la société Eramet-Comilog. L’objectif de ce travail est de préciser les conditions de formation de ce protore et de le replacer dans l’histoire du remplissage du bassin. Ce protore d'une épaisseur moyenne de 75 m est constitué de carbonates de manganèse ; il a fait l'objet d'une récente campagne de 24 forages carottés d'une profondeur moyenne de 125 m sur le plateau de Bangombé (Pl. Bangombé).A travers une approche pluridisciplinaire comprenant l'étude de ces forages et des affleurements clefs du bassin, ce travail porte sur la caractérisation i) de l'environnement de dépôt du protore et des séries qui l'encadrent (du toit du FA au toit du FB) ; ii) du mode de formation des carbonates de Mn à 2.1 Ga et iii) de l'architecture et de la répartition des hautes teneurs en Mn du protore représentant un gisement potentiel du futur.L’étude pétro-sédimentaire détaillée a permis de distinguer neuf unités (U1 à U9) au sein de la Formation FB organisées suivant un cycle rétrogradant jusqu’à U5 puis progradant jusqu’à U9. Ce découpage montre une évolution du milieu de dépôt depuis un domaine de shoreface contrôlé par des courants deltaïques (U1) évoluant vers des dépôts d’offshore restreint (U2). Ce bassin enregistre ensuite un système de chenaux-levées turbiditiques (U3) qui alimentent un réseau d'injectites reconnu sur l’ensemble du Pl. de Bangombé et qui traverse 150 m de série (U4 à U7) en affectant le protore et ainsi les teneurs en Mn. L'environnement de dépôt du protore (U5 et U6) marque l’isolement du bassin qui devient affamé et contrôlé par une sédimentation biochimique à l’origine du dépôt des carbonates de Mn. L'Unité 7 correspond à la réouverture des apports détritiques en domaine d'offshore supérieur puis en domaine de shoreface dominé par des dépôts de tempêtes et de chenaux sous-aquatiques deltaïques (U8), et enfin lagunaire (U9) dans lequel apparaissent les premiers métazoaires de l’histoire de la planète, suivant une séquence régressive.Une étude géochimique a permis de préciser les conditions de dépôt du protore qui se forme en milieu alcalin anoxique à sub-oxique. Dans ce milieu, nous montrons pour la première fois une précipitation directe des carbonates de Mn sous forme bactériomorphe induite par l'activité photosynthétique des cyanobactéries qui consomment le CO2/HCO3 et conduisant à une augmentation du pH favorable à la formation des carbonates de Mn. L'activité cyanobactérienne est conditionnée par l’absence de courants de fond qui augmentent la turbidité du milieu et stoppent cette dernière.Les corrélations diagraphiques et séquentielles permettent de préciser la répartition spatiale et temporelle du FB permettant ainsi de replacer le protore dans l’histoire tectono-sédimentaire du bassin. Une première phase syn-tectonique (U1 à U3) contrôle l’épaisseur et la mise en place de dépôts turbiditiques dans les parties subsidentes, de dépôts argileux sur les pentes et de dépôt de carbonates sur les hauts-fonds. La seconde phase post tectonique (U4 à U7) permet la mise en place de dépôts relativement isopaques, bien que le protore enregistre une subsidence plus importante au nord du Pl. de Bangombé. On observe ainsi, sur le Pl. de Bangombé, des teneurs en Mn qui augmentent vers le sud alors que l’épaisseur du protore augmente vers le NNE. Postérieurement au dépôt du FB, le protore est structuré par des failles qui le compartimentent en touches de piano limitant ainsi sa continuité sur le Pl. de BangombéThe Franceville Basin (2.1 Ga) in southeastern Gabon, hosts a black shale series well preserved (FB Formation) which represents an exceptional example of unmetamorphised Paleoproterozoic sediment strata. This basin includes the protore of one of the largest Mn-oxide laterite ore worldwide, mined by Eramet-Comilog. The aim of this this work is to determine formation conditions of this protore and to characterize the global sedimentary evolution of the FB Formation which include the protore. This 75 m thick protore is constituted of Mn carbonate-rich black shales which represent a potential ore deposit for the future. It was drilled, on the Bangombé plateau, during a recent campaign of 24 boreholes with an average depth of 125 m.Through multidisciplinary study on these cores and key outcrops of the basin, this work focuses on : i) the depositional environment of the Mn-protore and FB Formation ; ii) the processes of formation of the Mn-carbonates at 2.1 Ga and iii) the architecture and distribution of Mn-rich levels of the protore on the Bangombé Plateau.A detailed sedimentological and petrological study allowed us to redefine the division of the FB into nine units, named U1 to U9 from the base to the top. These units show a fine upward cycle up to U5 and a reverse coarse loop until U9. This division leads to a new interpretation to propose an evolution from a shoreface depositional environment controlled by deltaic currents (U1) to an offshore depositional environment with anoxic conditions (U2). In this basin, a system of submarine fan is developed, feeding a network of sand injections (injectites) covering the Bangombé plateau (70 km²) and with a thickness of 150 m affecting U4 to U7, including the Mn-protore. The protore depositional environment formed below the wave base limit (U4, U5 and U6) in a starved basin, controlled by biochemical sedimentation allowed the formation of Mn-carbonates. The end of starved basin, would allow the re-opening of the detrital input into the offshore basin (U7). This basin is then filled by storm bar deposits intersected by deltaic sub-aquatic channels (U8). The U9 unit corresponds to a quiet lagoon environment, allowing the multicellular organism development for the first time on the planet.A geochemical study allowed the characterization of the depositional environment of Mn-carbonates as an anoxic to sub-oxic and alkaline environment. For the first time, we showed that the manganese carbonates, present as bacteriomorph forms, are precipitated from the seawater by the mediated photosynthetic cyanobacterial activity, which allows CO2 / HCO3 depression of the environment and a local increase of pH. The cyanobacterial activity is controlled by the absence of bottom currents, which increase the detrital input. This would stop the activity of the cyanobacteria and thus would lead to the decrease of the Mn-concentration along the protore.Finally, well-log and a sequential correlation analyses allowed us to detail spatial and timing repartition of FB Formation deposit, controlled by a tectono-sedimentary model. We propose two- tectono-sedimentary phases. A first syn-tectonic phase (U1 to U3) controls the depocentres and sedimentation gaps. Turbidite coarse deposits are located in the most subsident part, clay deposits rather on the slope and carbonates on shoals. A second post-tectonic phase (U4 to U7) allows isopach deposits. The Mn-protore formed during the post-tectonic phase. However, it shows a variable thickness due to subsidence to the north of the Bangombé plateau. So, on the Bangombé plateau, Mn-contents increase towards the south, whereas the protore thickness increases towards the NNE. Moreover sand injectites decrease Mn-content in the eastern part of the Bangombé plateau and impact on the economic evaluation of the Mn-carbonates. Currently, the protore is structured by post-sedimentary faults, which lead to a non-continuity of the high Mn levels on the Bangombé plateau
3
Ghalei, Mohammad. "Study of the speciation of Tc and its homologous Mn and Re in concentrated carbonate solution under γ and He2+ irradiation." Thesis, Nantes, Ecole des Mines, 2015. http://www.theses.fr/2015EMNA0226/document.
Full textAbstract:
Ce projet s’inscrit dans le cadre d’une étude fondamentale liée à l'oxydation et la réduction de ces éléments sous irradiation γ et He²⁺. ⁺. Tout d'abord la technique d’électrochimie a été utilisée pour la réduction du Mn (VII) afin d'obtenir les meilleures conditions expérimentales. Car les expériences étant réalisées sous irradiation ainsi les radicaux carbonate qui sont produits par radiolyse jouent un rôle important dans les réactions. La cinétique de formation et la décroissance des radicaux carbonate dans les solutions de carbonate concentrées ont été étudiés par radiolyse pulsée β pico-seconde. Après la réduction du Mn (VII) et l'oxydation du Mn (II) dans une solution de carbonate ([CO₃²⁻] = 5 mol.l⁻¹) sont réalisées sous irradiation γ et He²⁺. Par des données obtenues pour H₂ produit, les spectres UV-Vis et structure finale, les mécanismes de la réaction sont discutés. Re (III) est oxydé facilement dans une solution de carbonate concentré sous irradiation (γ et He²⁺) mais Re (VII) ne peut être réduite à moins que l'addition de formiate afin d'empêcher la formation de radicaux carbonate. De la même façon, Tc (VII) ne peut être réduit dans les solutions concentrées de carbonate sous irradiation (γ et He²⁺) sans ajout de formiate. L'état d'oxydation du produit final de la réduction de Tc(VII) a été déterminée par spectroscopie XANES et est de + IV. En outre, la structure finale du produit final a été déterminée par spectroscopie EXAFS. Le mécanisme de la réaction, le rendement radiolytique de décroissance et la formation du Tc et l’effet de concentration du carbonate sur la produit final de la réduction du Tc(VII) sous irradiation sont discutésThis project is one part of the fundamental study and deals with theoxidation/reduction reactions and speciation of technetium and its homologous manganese and rhenium in highly concentrated carbonate solutions under γ and He²⁺ irradiation. Firstly the electrochemistry experiment is carried out for the reduction of Mn(VII) in order to obtain the best experimental conditions. As the experiments are performed under irradiation, the carbonate radicals,which are produced by radiolysis, play an important role in the reactions. The formation and decay kinetics of the carbonate radicals in concentrated carbonate solutions were studied by electron picosecond pulse radiolysis. The reduction of Mn(VII) and the oxidation of Mn(II) experiments in carbonate solution ([CO₃²⁻] = 5 mol.l⁻¹) are carried out under γ and He²⁺ irradiation. By the obtained data from the produced H₂, UV-Vis spectra and the final structure determination, the mechanisms of the reaction are discussed. Re(III)is oxidized easily in concentrated carbonate solution under irradiation (γ and He²⁺) but Re(VII) cannot be reduced unless addition of formate in order to prevent carbonate radical formation. Also Tc(VII) cannot be reduced in concentrated carbonate solutions under irradiation (γ and He²⁺) without formate addition. The oxidation state of the final product of reduction of Tc(VII) was determined by XANES spectroscopy and is +IV. Moreover, the final structure of the product was determined by EXAFS spectroscopy. The mechanisms of reaction, decay and formation radiolytic yield of Tc and also the effect of concentration of carbonate on final product of reduction ofTc(VII) under irradiation are discussed
4
Rafélis, Saint Sauveur Marc de. "Apport de l'étude de la spéciation du manganèse dans les carbonates pélagiques à la compréhension du contrôle des séquences eustatiques du 3ème ordre." Paris 6, 2000. http://www.theses.fr/2000PA066396.
Full text
5
Langlet, Denis. "Enregistrement haute fréquence des conditions environnementales par les tests de bivalves : application des techniques de marquage,cathodoluminescence et chimie à l'huître Crassostrea gigas de l' Etang de Thau (Hérault, France)." Paris 6, 2002. http://www.theses.fr/2002PA066425.
Full text
6
Burté, Luc. "Etude des risques de colmatage et optimisation des procédés de traitement des doublets géothermiques superficiels." Thesis, Rennes 1, 2018. http://www.theses.fr/2018REN1B019/document.
Full textAbstract:
Les doublets géothermiques sur aquifères superficiels jouent un rôle important en France pour le chauffage, le rafraichissement et la production d’eau chaude sanitaire des bâtiments. La pérennité de ces installations est cependant conditionnée par la possibilité de pouvoir garantir dans le temps la production puis la réinjection de l’eau souterraine. Le colmatage de la boucle géothermale est un problème majeur qui affecte de nombreuses installations sur l’ensemble du territoire français et remet en cause leur viabilité technico-économique. La compréhension et la prédiction de ce phénomène nécessite de nouveaux moyens de caractérisation et de modélisation des processus biogéochimiques couplés au fonctionnement des boucles géothermales dans des environnements de subsurface hétérogènes. Cette thèse a ainsi fait l’objet d’une nouvelle collaboration entre le laboratoire Géosciences Rennes et l’entreprise Antea group pour identifier les mécanismes à l’origine de ces phénomènes de colmatage et d’en caractériser les paramètres influents dans le but de construire un outil d’analyse des risques permettant l’anticipation de ces processus de colmatage. Le premier volet de la thèse expose la synthèse des typologies de colmatage (biogéochimique, chimique, biologique et physique). Cette synthèse est issue de l’étude de la littérature sur la problématique de colmatage des forages d’eau et des retours d’expérience concernant les doublets géothermiques recensés et étudiés durant cette thèse. Le second volet présente les inventaires régionaux des problématiques de colmatage recensées en France dans différents contextes hydrogéologiques. Ces inventaires ont permis de délivrer un état des lieux à grande échelle de la problématique de colmatage et d’étudier les contextes associés à chaque type de colmatage. Dans le troisième volet, de nouvelles méthodologies de caractérisation in-situ des phénomènes de colmatage biogéochimique liés à l’oxydation du manganèse et du fer sont présentées. Elles ont été développées dans le cadre de ces travaux de thèse à partir des investigations menées sur différents sites confrontés à des problèmes d’exploitation. Ces méthodologies d’investigations pluridisciplinaires couplent la mesure des propriétés hydrauliques, des concentrations en éléments chimiques et de la diversité microbienne afin d’identifier la problématique impactant le fonctionnement de l’installation et d’en définir in fine les causes. Le quatrième volet expose les résultats d’une campagne de terrain effectuée sur un doublet géothermique impacté par un processus de colmatage biogéochimique. Cette campagne a permis d’identifier les composantes clés de la réactivité biochimique impliquée dans le colmatage : distribution du flux, hétérogénéité chimique et diversité microbiologique. A l’aide du code de calcul PHREEQC, un modèle géochimique simulant les cinétiques de précipitation observées a été développé. Il permet l’étude quantitative des mécanismes biogéochimiques favorisant l’apparition rapide du colmatage. Enfin, les retours d’expériences de l’exploitation des doublets sur nappes superficielles ont démontré le besoin d’une méthodologie fiable d’analyse des risques, permettant d’anticiper l’apparition des processus de colmatage à chaque étape de la vie du projet. Ainsi, à partir de la synthèse de la littérature scientifique et technique et des conclusions des études menées durant cette thèse, les facteurs de risques d’apparition des phénomènes de colmatage ont été déterminés. L’analyse des risques de colmatage intégrant ces différents facteurs a été implémentée à travers l’élaboration de méthodes développées sous Python 3. L’outil ARCADE (Analyse des Risques de Colmatage et Aide à la Décision) a été conçu d’une part pour évaluer le risque et d’autre part pour informer l’utilisateur averti des bonnes pratiques et moyens préventifs. Ces bonnes pratiques d’analyse et de gestion préventive sont présentées dans le dernier volet de cette thèseThe sustainability of geothermal systems using shallow aquifers for heating, cooling and hot water production depends on the possibility to ensure, over long time-scales, the production and the reinjection of groundwater in the aquifer. Clogging of the geothermal loop is a major issue affecting the technical and economic viabilities of numerous operations in France. The understanding and prediction of this phenomenon requires new methods of characterization and modelling of biogeochemical processes coupled to the operation of geothermal loops in heterogeneous subsurface environments. This thesis is thus the result of a new collaboration between the Géosciences Rennes lab and Antea group to identify the mechanisms at the origin of clogging phenomena and characterize their controlling parameters, in order to establish a risk assessment tool allowing the anticipation of clogging processes. The first part of the thesis describes the main clogging processes (biogeochemical, chemical, biological and physical). This synthesis is the result of (1) the study of the literature dealing with the clogging of water wells and (2) our feedbacks on the geothermal doublets identified and studied during this thesis. The second part presents the regional inventories of shallow geothermal systems impacted by clogging problems identified in different hydrogeological contexts in France. These inventories provide a large-scale perspective of clogging phenomena and allow to study the contexts associated with each type of clogging processes. In the third part, new methodologies for the in-situ characterization of biogeochemical clogging phenomena linked to manganese and iron oxidation are presented through case studies of sites affected by clogging issues. These interdisciplinary studies couple the measurement of hydraulic properties, chemical element concentrations and bacterial diversity, to identify the specific issue impacting the operation and to define its causes. The fourth part presents the results of an interdisciplinary field campaign carried out on a geothermal doublet impacted by a biogeochemical clogging process. This campaign documented the key components involved in mixing induced biogeochemical reactivity: flow distribution, chemical heterogeneity and microbiological diversity. Using PHREEQC, a geochemical model simulating observed kinetics of precipitation was developed in order to quantitatively explore the biogeochemical mechanisms favoring rapid clogging. Feedback from shallow geothermal systems operation has demonstrated the need for a reliable risk analysis methodology that allowed to anticipate the apparition of clogging processes at each stage of the project life (part 5). From the synthesis of the scientific & technical literature and the conclusions of the studies carried out during this thesis, the risk factors for the appearance of clogging phenomena were determined. A clogging risk analysis integrating these factors was implemented through the development of methods developed under Python 3. The methodology of the ARCADE tool (Analyse des Risques de Colmatage et Aide à la Décision) is designed to assess the risk and to inform users of good practices and preventive methods. These good practices for analysis and preventive methods are presented in the last part of this thesis
7
Guiyeligou, Grace Daniella. "Étude paléo-environnementale des dépôts manganésifère paléoprotérozoique (2.1 Ga-GABON)." Thesis, Poitiers, 2019. http://www.theses.fr/2019POIT2321.
Full textAbstract:
Le Paléoprotérozoïque est une période cruciale de l’histoire de la Terre. Un des évènements importants enregistré à cette époque est celui connu sous le nom de Great Oxidation Event (GOE) de 2,45 à 2,32 Ga. Cet évènement va entrainer des changements globaux à l’échelle de la planète. Il va impacter les conditions physico-chimiques en favorisant une altération oxydante des continents. Cette dernière est à l’origine de l’explosion progressive des cyanobactéries photosynthétiques responsables d’une oxydation importante du milieu. Une vie multicellulaire complexe et organisée s’est développée suite à cet évènement. Le bassin paléoprotérozoïque (2,1 à 2,0 Ga) de Franceville, situé au Sud-est du Gabon montre des dépôts sédimentaires en très bonne état de conservation et constitue une archive exceptionnelle pour retracer les processus de dépôts de cette période. La série sédimentaire francevillienne est composée de quatre formations lithostratigraphiques de FA à FD. Les accumulations de manganèse sont spécifiquement visibles au niveau des zones de plateaux ou les plus importantes réserves sont situées dans les plateaux de Bangombé et d’Okouma. Ce travail accorde une attention particulière à la formation FB et plus particulièrement les sous-unités FB1b et FB1c situées sur le site Okouma où sont retrouvés des dépôts de fer, phosphore et de manganèse. Une étude pluridisciplinaire et multi-échelle s’est portée sur sept sondages d’Okouma, mis à disposition par la compagnie minière Eramet-Comilog. L’étude sédimentologique des différents échantillons a permis de diviser les sondages en trois unités : 1- inférieure constituée de faciès détritiques et notamment les pélites rubanées (FB1b), 2- une unité dite de transition qui marque le passage des formations FB1b à FB1c avec des faciès carbonatés riches en pyrite appelé dans ce travail black shales pyriteux et carbonates ferrifères et 3- une unité supérieure représentée par des blacks shales manganésifères ou s’intercale des grès fins à moyens. Ces faciès témoignent la mise en place d’un environnement marin d’une phase de transgression ayant débuté à la transition FA-FB. Les analyses pétrographiques et minéralogiques ont mis en évidence des minéraux argileux composés d’illite, chlorite et interstratifiés illite/ smectite. La réaction d’illitisation est quasiment achevée (90 % d’illite) comme en témoigne les interstratifiés ordonnés (R3). Les analyses géochimiques montrent que la formation FB1b est dominée par des matériaux détritiques tandis que ceux de la formation au-dessus FB1c par des processus chimiques. De même la plupart des éléments sensibles au redox (Mn, Zn, Ni, Co, Mo, Cd et Cu) montrent un changement redox passant d’un environnement oxique (FB1b) à anoxique (FB1c)Paleoproterozoic is a crucial period in the history of the Earth. One of the major events recorded at that time was the Great Oxidation Event (GOE) from 2.45 to 2.32 Ga. This event will lead to global changes on a global scale. It will impact the physico-chemical conditions by promoting oxidative alteration of the continents. The latter is at the origin of the progressive explosion of photosynthetic cyanobacteria responsible for a significant oxidation of the environment. A complex and organized multicellular life developed as a result of this event. The Paleoproterozoic basin (2.1 to 2.0 Ga) of Franceville, located in southeastern Gabon, shows sedimentary deposits in a very good state of conservation and constitutes an exceptional archive to trace the deposition processes of this period. The francevillian sedimentary series is composed of four lithostratigraphic formations from FA to FD. Manganese accumulations are specifically visible in the plateau areas where the largest reserves are located in the Bangombé and Okouma plateaus. This work pays particular attention to the FB formation and more particularly the FB1b and FB1c subunits located on the Okouma site where iron, phosphorus and manganese deposits are found. A multidisciplinary and multi-scale study was carried out on seven Okouma holes, provided by the mining company Eramet-Comilog. The sedimentological study of the various samples made it possible to divide the holes into three units: 1- lower, consisting of detrital facies and in particular banded heterolithics (FB1b), 2- a so-called transition unit that marks the passage of the FB1b to FB1c formations with carbonate facies rich in pyrite called in this work black shales pyriteux and iron carbonates and 3- a higher unit represented by manganiferous shale blacks or is interposed by fine medium sandstones. These facies testify to the establishment of a marine environment from a phase of transgression that began at the FA-FB transition. Petrographic and mineralogical analyses have revealed clay minerals composed of illite, chlorite and interlayered illite/smectite. The illitization reaction is almost complete (90% illite) as shown by the ordered interlayered (R3). Geochemical analyses show that the FB1b formation is dominated by detrital materials while those of the formation above FB1c are dominated by chemical processes. Similarly, most redox sensitive elements (Mn, Zn, Ni, Co, Co, Mo, Cd and Cu) show a redox change from an oxic environment (FB1b) to anoxic (FB1c)
8
Eames, Douglas J. "Direct causticizing of sodium carbonate with manganese oxide." Diss., Georgia Institute of Technology, 2000. http://hdl.handle.net/1853/7026.
Full text
9
Ferreira, Joaquim Matheus Freire. "Preparação de óxidos de zinco e manganês, via precipitação em solução homogênea, para utilização na agricultura como adubo foliar." Universidade de São Paulo, 2009. http://www.teses.usp.br/teses/disponiveis/97/97136/tde-27092012-125329/.
Full textAbstract:
A agricultura no Brasil vem se destacando ao longo dos anos como uma das principais atividades econômicas do país. A grande extensão em área, o clima favorável, os investimentos em pesquisa e o aumento da população mundial, vem auxiliando o Brasil a se destacar como celeiro mundial. O grande desafio, portanto, para uma agricultura sustentável é produzir mais sem desmatar os fragmentos ainda existentes de mata original. Para isso, uma das linhas de pesquisa que apresenta grande perspectiva de desenvolvimento é a de pesquisa do uso de fertilizantes que possam promover um suprimento eficiente das exigências nutricionais das plantas respeitando a atual exigência de proteção ao meio-ambiente. Este trabalho apresenta uma metodologia de preparação de óxidos de zinco e manganês hidratados para serem utilizados em formulações de adubos foliares. Utilizou-se para isto o método de precipitação em solução homogênea utilizando o experimento fatorial fracionado saturado Placket - Burman como ferramenta de trabalho. Inicialmente estudou-se a influência de fatores como: tipo de agente precipitante, rotação do agitador mecânico, excesso do agente precipitante e ordem de adição dos reagentes, pois influenciam diretamente na precipitação dos compostos. Estudou-se a distribuição do tamanho das partículas geradas, tomando esta variável resposta como parâmetro para a otimização da metodologia de síntese. Com os resultados obtidos pelo Planejamento Placket - Burman observou-se que o fator excesso de agente precipitante pouco influenciou na variável resposta. A partir dos fatores que mais influenciaram, montou-se nova matriz, agora com planejamento fatorial completo 23. Os fatores que mais influenciaram a variável resposta foram o tipo do agente precipitante, a ordem de adição dos reagentes e rotação do agitador mecânico. Observou-se portanto, com auxilio dos efeitos, a importância de cada fator na variável resposta. Os materiais obtidos foram caracterizados, por meio de difração de raios-X (DRX), analise térmica (TG), espectroscopia de infra-vermelho com transformada de Fourier (FTIR), microscopia eletrônica de varredura (MEV) e espectrofotometria de absorção atômica por chama (AAS). A distribuição do tamanho de partículas foi de 17,01 μm para o hidroxicarbonato de zinco e 5,32 μm para o carbonato de manganês. O hidroxicarbonato de zinco apresentou um teor de zinco em torno de 54,0 %, e, nesta matriz experimental, foi possível chegar a um modelo com bom ajuste para esta síntese. O carbonato de manganês, por sua vez, apresentou as um teor de Manganês em torno de 44,0 % e características adequadas de granulometria para ser utilizado como adubo foliar.The agriculture in Brazil has been standing out throughout the years as one of the main economical activities of the country. The great extension of the area, the favorable climate, the investments in research and the increase of the world population, has been assisting Brazil to stand out as a world barn. The great challenge, therefore, to a supportable agriculture is to produce more without deforesting the fragments still existing of original forest. That is, one of the methods of research which presents great perspective of development is the research of the use of fertilizer which can promote an efficient supply of the plants nutritional demanding respecting the current environmental protection demand. This work presents a methodology of mustered zinc and manganese oxide preparation to be used in formulations of leaf fertilizer. It was used for it, the precipitation in homogeneous solution method, using the fractioned factorial saturated experiment Packet-Burman as a work tool. Initially, it was studied the influence of the factors as: the type of precipitant agent, rotation of the mechanical shaker, excess of precipitant agent and the order of the addictions of the agents, for they influence directly in the compounds precipitation. It was studied the distribution of the size of the generated particles, taking this changeable response as a standard to a optimizing of the synthesis methodology. With the results obtained by the Planning Placket-Burman it was observed that the factor precipitant agent excess has little influenced the changeable response. From the factors on which most influenced them, it was set a new nuance up, now with a completed factorial planning 2.The factors which more influenced the changeable response were the type of precipitant agent, the order of reagent addiction and the rotation of the mechanic shaker. It was observed, therefore, with the help of the effects, the importance of each factor in the changeable response. The materials obtained were characterized, through the X-Ray diffraction(XRD), thermal analysis(TG), spectroscopy of infrared with transformed of Fourier(FTIR), eletronic microscopy with sweeping (MEV) and espectrophotometry of atomic absortion by flame (ASS). The distribution of the size of particles was 17,01 μm to the hidroxicarbonate of zinc and 5,32 μm to the carbonate of manganese. The hydroxicarbonate of Zinc has presented a level of Zinc around 54,0% and, in this experimental matrix, it was possible to get to a model with a good tunning for this synthesis. The manganese carbonate, on the other hand, has presented a level of manganese around 44,0% and adequate characteristics of particle sizes for being used as foliar fertilizer.
10
FERNANDES, ALBERTO de A. "Desenvolvimento de processo quimico para obtencao da nsutita (gama-MnO sub(2)) de alta densidade empregada na fabricacao de pilhas." reponame:Repositório Institucional do IPEN, 2002. http://repositorio.ipen.br:8080/xmlui/handle/123456789/11021.
Full textAbstract:
Made available in DSpace on 2014-10-09T12:47:03Z (GMT). No. of bitstreams: 0Made available in DSpace on 2014-10-09T14:08:48Z (GMT). No. of bitstreams: 1 07916.pdf: 4553798 bytes, checksum: eb42be1de889c1f95e7ccdc661406a8d (MD5)
Dissertacao (Mestrado)
IPEN/D
Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP
Books on the topic "Carbonates de manganèse"
1
Márta, Polgári. A Mn geokémiája a feketepala képzödés és a diagenetikus folyamatok tükrében = Manganese geochemistry- reflected by black shale formation and diagenetic processes: Az Úrkúti karbonátos mangánérc képzödési modellje = model of formation of the carbonatic manganese ore of Úrkút. Budapest: Interbridge Fundation & Karpati Publish House, 1993.
Find full text
2
Kirchman, David L. Introduction to geomicrobiology. Oxford University Press, 2018. http://dx.doi.org/10.1093/oso/9780198789406.003.0013.
Full textAbstract:
Geomicrobiology, the marriage of geology and microbiology, is about the impact of microbes on Earth materials in terrestrial systems and sediments. Many geomicrobiological processes occur over long timescales. Even the slow growth and low activity of microbes, however, have big effects when added up over millennia. After reviewing the basics of bacteria–surface interactions, the chapter moves on to discussing biomineralization, which is the microbially mediated formation of solid minerals from soluble ions. The role of microbes can vary from merely providing passive surfaces for mineral formation, to active control of the entire precipitation process. The formation of carbonate-containing minerals by coccolithophorids and other marine organisms is especially important because of the role of these minerals in the carbon cycle. Iron minerals can be formed by chemolithoautotrophic bacteria, which gain a small amount of energy from iron oxidation. Similarly, manganese-rich minerals are formed during manganese oxidation, although how this reaction benefits microbes is unclear. These minerals and others give geologists and geomicrobiologists clues about early life on Earth. In addition to forming minerals, microbes help to dissolve them, a process called weathering. Microbes contribute to weathering and mineral dissolution through several mechanisms: production of protons (acidity) or hydroxides that dissolve minerals; production of ligands that chelate metals in minerals thereby breaking up the solid phase; and direct reduction of mineral-bound metals to more soluble forms. The chapter ends with some comments about the role of microbes in degrading oil and other fossil fuels.
Book chapters on the topic "Carbonates de manganèse"
1
Böttcher, Michael E. "Manganese (Sedimentary Carbonates and Sulfides)." In Encyclopedia of Geobiology, 541–42. Dordrecht: Springer Netherlands, 2011. http://dx.doi.org/10.1007/978-1-4020-9212-1_130.
Full text
2
Tu, Zhongbing, Xiaoping Liang, Xiangguan Yang, Shilei Ren, Chengbo Wu, and Yu Wang. "Recovery of Manganese by Roasting-Ammonia Leaching from Low-Grade Manganese Carbonate Ores." In Rare Metal Technology 2019, 99–107. Cham: Springer International Publishing, 2019. http://dx.doi.org/10.1007/978-3-030-05740-4_11.
Full text
3
Wang, Lin, Yan-hong Li, Jin-lin Lu, Wei Xu, and Hui-long Lin. "Thermal Decomposition Kinetics of Manganese Carbonate In the Process of MnZn Ferrite Preparation." In TMS 2016: 145thAnnual Meeting & Exhibition: Supplemental Proceedings, 335–42. Hoboken, NJ, USA: John Wiley & Sons, Inc., 2016. http://dx.doi.org/10.1002/9781119274896.ch40.
Full text
4
Wang, Lin, Yan-hong Li, Jin-lin LU, Wei XU, and Hui-long Lin. "Thermal Decomposition Kinetics of Manganese Carbonate in the Process of MnZn Ferrite Preparation." In TMS 2016 145th Annual Meeting & Exhibition, 335–42. Cham: Springer International Publishing, 2016. http://dx.doi.org/10.1007/978-3-319-48254-5_40.
Full text
5
Fang, Ting, and Jenq Gong Duh. "Synthesis of Well-Crystallized Manganese Oxide from Precipitation: Effect of Introducing Carbonate Anions." In High-Performance Ceramics III, 687–92. Stafa: Trans Tech Publications Ltd., 2007. http://dx.doi.org/10.4028/0-87849-959-8.687.
Full text
6
Nishri, Aminadav, and Arie Nissenbaum. "Formation of manganese oxyhydroxides on the Dead Sea coast by alteration of Mn-enriched carbonates." In Saline Lakes V, 61–73. Dordrecht: Springer Netherlands, 1993. http://dx.doi.org/10.1007/978-94-011-2076-0_5.
Full text
7
Fan, D., T. Liu, P. Yang, and J. Ye. "Occurrence of Anthraxolite (Bitumen) Spheroids in Xiangtan-Type Manganese Carbonate Deposits of South China." In Bitumens in Ore Deposits, 447–58. Berlin, Heidelberg: Springer Berlin Heidelberg, 1993. http://dx.doi.org/10.1007/978-3-642-85806-2_24.
Full text
8
"manganese carbonate." In Dictionary Geotechnical Engineering/Wörterbuch GeoTechnik, 837. Berlin, Heidelberg: Springer Berlin Heidelberg, 2014. http://dx.doi.org/10.1007/978-3-642-41714-6_130377.
Full text
9
"carbonate of manganese." In Dictionary Geotechnical Engineering/Wörterbuch GeoTechnik, 192. Berlin, Heidelberg: Springer Berlin Heidelberg, 2014. http://dx.doi.org/10.1007/978-3-642-41714-6_30511.
Full text
10
"Manganese Carbonates in Modern Sediments." In Isotope Geochemistry, 5–62. Elsevier, 2017. http://dx.doi.org/10.1016/b978-0-12-803165-0.00002-1.
Full textConference papers on the topic "Carbonates de manganèse"
1
Alvani, Carlo, Mariangela Bellusci, Aurelio La Barbera, Franco Padella, Marzia Pentimalli, Luca Seralessandri, and Francesca Varsano. "Reactive Pellets for Improved Solar Hydrogen Production Based on Sodium Manganese Ferrite Thermochemical Cycle." In ASME 2008 2nd International Conference on Energy Sustainability collocated with the Heat Transfer, Fluids Engineering, and 3rd Energy Nanotechnology Conferences. ASMEDC, 2008. http://dx.doi.org/10.1115/es2008-54170.
Full textAbstract:
Hydrogen production by water-splitting thermochemical cycle based on manganese ferrite /sodium carbonate reactive system is reported. Two different preparation procedures for manganese ferrite/sodium carbonate mixture were adopted and compared in terms of materials capability to cyclical hydrogen production. According to the first procedure conventionally synthesized manganese ferrite, i. e. high temperature (1250 °C) heating in Ar of carbonate/oxide precursors, was mixed with sodium carbonate. The blend was tested inside a TPD reactor using a cyclical hydrogen production/material regeneration scheme. After few cycles the mixture resulted rapidly passivated and unable to further produce hydrogen. An innovative method that avoids the high temperature synthesis of manganese ferrite is presented. This procedure consists in a set of consecutive thermal treatments of a manganese carbonate/sodium carbonate/iron oxide mixture in different environments (inert, oxidative, reducing) at temperatures not exceeding 750 °C. Such material, whose observed chemical composition consists in manganese ferrite and sodium carbonate in stoichiometric amount, is able to evolve hydrogen during 25 consecutive water-splitting cycles, with a small decrease in cyclical production efficiency.
2
Mohapatra, Ashwini, and Abhas Singh. "EFFECT OF MANGANESE ON FLUORIDE MOBILIZATION IN HIGH CARBONATED GROUNDWATER." In GSA 2020 Connects Online. Geological Society of America, 2020. http://dx.doi.org/10.1130/abs/2020am-349049.
Full text
3
Alghamdi, A., S. Salah, M. Otaibi, S. Ayirala, and A. Yousef. "Low pH Manganese Assisted Waterflooding Processes for Enhanced Oil Recovery in Carbonates." In IOR 2021. European Association of Geoscientists & Engineers, 2021. http://dx.doi.org/10.3997/2214-4609.202133022.
Full text
4
FEDUTIK, Yu A., A. A. ANTIPOV, and G. B. SUKHORUKOV. "MANGANESE CARBONATE PARTICLES PREPARATION BY COLLOIDAL AGGREGATION FOR HOLLOW POLYELECTROLYTE CAPSULES FABRICATION." In Physics, Chemistry and Application of Nanostructures - Reviews and Short Notes to Nanomeeting 2003. WORLD SCIENTIFIC, 2003. http://dx.doi.org/10.1142/9789812796738_0081.
Full text
5
Ai, Jiayi, Sandra Siljeström, Ningning Zhong, Simon George, and Lijuan Huang. "Microbially-Mediated Formation of Manganese Carbonates Hosted in Cryogenian Black Shales in South China." In Goldschmidt2020. Geochemical Society, 2020. http://dx.doi.org/10.46427/gold2020.22.
Full text
6
Zhao, Zhixi, Shanlin Zhao, and Yongfeng Jia. "Notice of Retraction: Oxidation of As(III) by Hydrous Manganese Oxide: Effect of Carbonate." In 2011 5th International Conference on Bioinformatics and Biomedical Engineering. IEEE, 2011. http://dx.doi.org/10.1109/icbbe.2011.5780763.
Full text
7
Fitzgerald, Eliza J., and Justin B. Richardson. "THE INFLUENCE OF MICROBIAL COMMUNITIES AND SECONDARY OXIDES ON MANGANESE CARBONATE AND AMPHIBOLITE WEATHERING." In 54th Annual GSA Northeastern Section Meeting - 2019. Geological Society of America, 2019. http://dx.doi.org/10.1130/abs/2019ne-327926.
Full text
8
Richardson, Justin B. "MANGANESE UPTAKE BY NORTHERN HARDWOODS ON MN-CARBONATE RICH MINE-TAILINGS – A GEOCHEMICAL CONUNDRUM IN WESTERN MASSACHUSETTS." In 54th Annual GSA Northeastern Section Meeting - 2019. Geological Society of America, 2019. http://dx.doi.org/10.1130/abs/2019ne-328032.
Full text
9
Puranen, Jouni, Leo Hyva¨rinen, Juha Lagerbom, Mikko Kylma¨lahti, Heli Koivuluoto, and Petri Vuoristo. "Manganese-Cobalt Spinel Coatings for SOFC Metallic Interconnects Manufactured by Conventional Plasma Spraying (PS) and Suspension Plasma Spraying (SPS)." In ASME 2011 9th International Conference on Fuel Cell Science, Engineering and Technology collocated with ASME 2011 5th International Conference on Energy Sustainability. ASMEDC, 2011. http://dx.doi.org/10.1115/fuelcell2011-54750.
Full textAbstract:
Protective coatings are used on ferritic stainless steel interconnects of solid oxide fuel cells (SOFCs) to prevent the oxidation and evaporation of volatile chromium compounds. Oxide scale is formed of chromium oxide (Cr2O3) which tends to react with the oxygen and water, forming chromium trioxide (CrO3) and chromium hydroxides (Cr2(OH)2). These compounds will migrate to the triple phase barrier (TPB) of a cathode and reduce back to Cr2O3. This reaction pathway is a notable reason for the degradation phenomena of the cell. Plasma spraying (PS) and suspension plasma spraying (SPS) were studied as possible manufacturing processes for thin Mn-Co-(Fe) spinel coatings. Powder for PS was manufactured by using a solid state reaction method from carbonates and oxide to form a MnCo1.8Fe0.2O4 and powder for SPS by co-precipitation process from nitrates to form a MnCo2O4 spinel structure. Using PS, coatings with thin and relatively dense structures were obtained. The composition of the coatings was homogeneous although, the decomposition of the spinel structure was noticed. The crystal structures of the PS coatings were partially restored by a separate annealing process. The spray parameters had a strong influence on the coating structure and the composition when SPS was used. The most homogenous coating structure was formed when low energy spraying parameters were used, whereas high energy parameters formed a columnar structure with larger cobalt rich areas. The decomposed spinel structure of the SPS coatings were fully restored by the annealing treatment. In SPS, more process optimization is needed to improve the coating quality and especially denseness.
10
Torrao, Guilhermina, Robert Carlino, Steve L. Hoeffner, and James D. Navratil. "Characterization of Plutonium Contaminated Soils From the Nevada Test Site for Remediation Method Selection." In ASME 2003 9th International Conference on Radioactive Waste Management and Environmental Remediation. ASMEDC, 2003. http://dx.doi.org/10.1115/icem2003-4610.
Full textAbstract:
Plutonium (239/240Pu) contamination in soils is an environmental concern at many U.S. Department of Energy (DOE) sites. Remediation actions have been attempted using different technologies, and clean-up plans have been implemented at several sites, such as the Nevada Test Site (NTS). During the 1950’s and early 1960’s, nuclear weapons testing at and near the NTS resulted in soil contaminated with plutonium particles. Clean-up efforts are continuing using conventional remediation techniques. However, the DOE desires to obtain technologies that can further reduce risks, reduce clean-up costs, and reduce the volume of contaminated soil for disposal. Low levels of plutonium contamination are distributed somewhat uniformly throughout the NTS soils and, as a result, it is difficult to obtain volume reductions above 70%. The subject of this research was to characterize the plutonium-contaminated soil from the Tonopah Test Range (TTR) north of the NTS. In order to select remediation methods, it is important to gain a better understanding of how plutonium is bound to the contaminated soil; thus, size separation, magnetic separation, and the sequential extraction (SE) methods were used for this purpose. The SE method consisted of targeting five operationally defined geochemical phases: ion exchangeable, bound to carbonates, bound to iron and manganese oxides (reducible), bound to organic matter, and resistant. Radiometric measurements were used to determine plutonium in each of these defined phases in the soil. Selected stable elements were also determined, to compare the operation of the SE method to other investigators. The SE experiments were performed with two types of samples: soil without heat treatment and soil with heat treatment. The MF treatment was used to destroy the organic content in the soil so as to further evaluate the SE procedure. Particle size analysis indicated that approximately 37% of the TTR soil by weight was larger than 300 micrometers and this fraction contained little plutonium, < 100 pCi/g. Thus, size separation may be useful as part of a remediation process. Magnetic separation tests showed that the magnetic fraction of the TTR soils is very small, and the non-magnetic fraction still contained the majority of the plutonium. Thus, a magnetic separation step in a treatment process would not be useful. Following SE, analysis results of the stable elements agreed with reported values. The SE results also indicated an association of plutonium with the organic and resistant defined phases. The main change in 239/240Pu distribution following heat treatment was an increase of plutonium recovery in the reducible phase. The SE results showed that fairly aggressive chemical treatment would be required if leaching were part of a remediation process.