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Paleoenvironment evolution of the East Philippine Sea recorded in the new-type ferromanganese crust since the terminal Late Miocene

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Science China Earth Sciences 2007年第8期50卷 1179-1188页

作者： XU ZhaoKai LI AnChun JIANG FuQing LI TieGang MENG QingYong JIN Ning Key Laboratory of Marine Geology and Environment Institute of OceanologyChinese Academy of SciencesQingdao 266071China Graduate University of Chinese Academy of Sciences Beijing 100039China

From systemic research of microstructure, geochemistry, uranium-series and 10Be isotope dating on a new-type deepwater ferromanganese crust from the East Philippine Sea, the paleoenvironment evolu-tion of the target area since the terminal Late Miocene was recovered. The vertical section changes of microstructure and chemical composition are consistent in the studied crust, which indicate three major accretion periods and corresponding paleoenvironment evolution of the crust. The bottom crust zone was formed in the terminal Late Miocene (5.6 Ma) with loose microstructure, high detritus content and high growth rate. Reductions of mineral element content, accretion rate and positive Ce-anomaly degree at 4.6 Ma indicate temporal warming, which went against the crust accretion and finally formed an accretion gap in the terminal Middle Pliocene (2.8―2.7 Ma). The more active Antarctic bottom sea-waters in the Late Pliocene (2.7 Ma) facilitated the fast transfer to the top pure crust zone. Hereafter, with the further apart of volcanic source and the keeping increase of eolian material (1.0 Ma), although surrounding conditions were still favorable, mineral element content still shows an obvious reducing trend. It thereby offers new carrier and data for the unclear paleoceanographic research of the target area since the terminal Late Miocene.

关键词： new-type ferromanganese crust record paleoenvironment evolution uranium-series dating 10Be isotope dating East Philippine Sea

The relationship between the growth process of the ferromanganese crusts in the Pacific seamount and Cenozoic ocean evolvement

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Science China Earth Sciences 2009年第8期52卷 1091-1103页

作者： DING Xuan GAO LianFeng FANG NianQiao QU WenJun LIU Jian LI JiangShan School of Marine Science China University of GeosciencesBeijing 100083China College of Resources and Environments Hebei Polytechnic UniversityTangshan 063009China National Geologic Experiment and Test Center Beijing 100037China Guangzhou Marine Geological Survey Guangzhou 510075China

Base on the Os isotope stratigraphy together with the empirical growth rate models using Co concentrations, the growth ages of the ferromanganese crusts MHD79 and MP3D10 distributed in the seamount of Pacific are confirmed. Through the contrast and research on the previous achievements including ODP Leg 144 and the crusts CD29-2, N5E-06 and N1-15 of the seamount of the Central Pacific, the uniform five growth and growth hiatus periods of them are found, and closely related to the Cenozoic ocean evolvement process. In the Paleocene Carbon Isotope Maximum (PCIM), the rise of the global ocean productivity promoted the growth of the seamount crust; the first growth hiatus (I) of the ferromanganese crust finished. In the Paleocene-Eocene Thermal Maximum (PETM), though the vertical exchange of seawater was weakened, the strong terrestrial chemical weathering led to the input of a great amount of the terrigenous nutrients, which made the bioproductivity rise, so there were no crust hiatuses. During 52-50 Ma, the Early Eocene Optimum Climate (EECO), the two poles were warm, the latitudinal temperature gradient was small, the wind-driven sea circulation and upwelling activity were weak, the terrestrial weathering was also weakened, the open ocean bioproductivity decreased, and the ferromanganese crust had growth hiatus again (II). From early Middle Eocene-Late Eocene, Oligocene, it was a long-term gradually cooling process, the strengthening of the sea circulation and upwelling led to a rise of bioproductivity, and increase of the content of the hydrogenous element Fe, Mn and Co and the biogenous element Cu, Zn, so that was the most favorable stage for the growth of ferromanganese crust (growth periods III and IV) in the studied area. The hiatus III corresponded with the Eocene-Oligocene boundary, is inferred to relate with the global climate transformation, celestial body impact event in the Eocene-Oligocene transition. From the early to the middle Miocene, a large-scale growth hiatus (hiatus period IV) of the ferromanga

关键词： Pacific seamount ferromanganese crust growth period and growth hiatus period Cenozoic ocean evolvement

New evidence of microbe origin for ferromanganese nodules from the East Pacific deep sea floor

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Science China Earth Sciences 2000年第2期43卷 187-192页

作者：胡文宣周怀阳顾连兴张文兰陆现彩符琦潘建明张海生 Department of Earth Sciences State Key Laboratory of Mineral Deposit Research Nanjing University Nanjing China Second Institute of Oceanography State Oceanic Administration Hangzhou China State Key Laboratory of Mineral Deposit Research Nanjing University Nanjing China

Using a fluorescence microscope and EPMA, abundant microbe "bodies" and clear mi-crobic fluorescent microstructure are determined in the ferromanganese nodules recently collected from the East Pacific deep sea floor. The microbic fluorescent structure shows a close relation to the formation of the ferromanganese nodules. According to their morphological features, the microbes are classified into two types: one is named clumpy microbe, which takes a bar-shaped manganese mineral as a pillar and grows like fasciculate coral, resulting in irregular cauliflorate nodules with rough surfaces; the other is called filamentous microbe, which grows in very thin arcuate and/or concentric circular laminae composed of a microbe layer and a metal (manganese and iron)-rich layer, leading to potato-shaped nodules with relatively smooth surfaces. It also can be seen that the two types of microbes are intergrown together, resulting in nodules complicated in compositions and shapes.

关键词： ferromanganese nodule microbic fluorescent microstructure clumpy microbe filamentous microbe.

Evaluation of reduction roasting and magnetic separation for upgrading Mn/Fe ratio of fine ferromanganese

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International Journal of Mining Science and Technology 2013年第4期23卷 529-533页

作者： Makhula Mpho Bada Samson Afolabi Ayo School of Chemical and Metallurgical Engineering Faculty of Engineering and the Built Environment University of the Witwatersrand Johannesburg South Africa Department of Mineral Processing Division Johannesburg South Africa Department of Civil and Chemical Engineering University of South Africa College of Science Engineering and Engineering Johannesburg South Africa

Low grade ferromanganese tailing was subjected to different mineralogical techniques, reduction roasting and magnetic separation to establish whether commercially acceptable manganese qualities and high Mn/Fe ratio could be obtained, and also to determine the best processing route for beneficiating this ore. The main manganese mineral within the feed sample is birnessite, with minor amounts of pyrolusite and todorokite. Size by assay analysis conducted presented a result with a yield of about 35.75% and Mn grade of 27.63% to coarse (−3.35 + 1 mm) and yield of 20.24% and Mn grade of 27.71% to (−1.18 + 0.50 mm) fraction. Two-stage high induced magnetic separations at 16,000 and 11,000 G produces Mn grades with similar grade to that obtained from the ferromanganese feed sample. Reduction roasting followed by magnetic separation on −1.18 + 0.50 mm at 1000 G recovered 72.31% Mn with a grade of 58.44% Mn, 2.52% Fe and 3.29% Si at Mn/Fe ratio of 23.22. This study reveals the influence of roasting in converting the hematite and goethite to magnetite and the response of the roasted fraction to magnetic separation.

关键词： ferromanganese Mn/Fe ratio Magnetic separation Mineralogy Reduction roasting

Activation Energy of Nitriding Medium Carbon ferromanganese Alloy

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Journal of Iron and Steel Research(International) 2013年第1期20卷 58-61,78页

作者： Saeed N Ghali Mamdouh M Eissa Micheal L Mishreky Steel Technology Department Central Metallurgical Research and Development Institute (CMRDI)Helwan 11421CairoEgypt

Investigation of some kinetics aspects of the reaction between nitrogen and medium carbon ferromanganese （MC-FeMn） was made. Nitriding process of fine medium carbon ferromanganese was carried out at temperature ranging from 973 to 1 223 K and time up to 480 min. Nitriding was carried out under nitrogen and hydrogen gas pressures. At temperature of 573 K, hydrogen gas was injected with pressure of about 0.2 MPa followed by injection of nitrogen gas up to 1.2 MPa. Sample mass was 35 g, nitrided in cylindrical chamber with 34 mm in inner diameter and 1 200 mm in length. The change in nitrogen pressure was taken as an indication for nitrogen pickup. The mass gain i.e. nitrogen pickup in kilograms per surface area （m2） was determined by time at different temperatures. Nitriding rate constants were calculated and the activation energy of nitriding process was derived from Arrhenius equation. The nitriding rate constant was found to be increased by increasing temperature of the reaction. The activation energy of nitriding process of fine medium carbon ferromanganese at time ranging up to 28 800 s is around 140 kJ/mol. It was found that the rate controlling step of the nitriding process of MC-FeMn is diffusion mechanism.

关键词： nitriding ferromanganese gas solid reaction activation energy

MAIN FACTORS STUDY OF THE CONTROLLING GEOCHEMICAL CHARACTERISTICS OF ferromanganese NODULES (Ⅰ)——GEOCHEMICAL CHARACTERISTICS OF ferromanganese NODULES

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Science China Chemistry 1992年第3期35卷 375-384页

作者：鲍根德 The Second Institute of Oceanography State Oceanic Administration Hangzhou 310012 PRC

The geochemical characteristics of ferromanganese nodules have been described in detail by the information study of major elements, trace elements, rare earth elements and infrared spectrophotometer, X-ray diffraction, electronic probing, electronic microscope analysis in 57 ferromanganese nodules of different types from the South China Sea and the Northern Central Pacific Basin. The result shows that (ⅰ) the different types of ferromanganese nodules have different geochemical characteristics; (ⅱ) there is a close relationship between Mn/Fe in ferromanganese nodules and their element content, mineral composition, nodule abundance, tenor (Cu+Co+Ni)%, growth Speed and sedimentary environment. It has suggested that Mn/Fe in nodules can be an indicator of classifying ferromanganese nodule types.

关键词： ferromanganese nodule geochemical characteristics the South China Sea the Northern Central Pacific.

The long-term effectiveness of ferromanganese biochar in soil Cd stabilization and reduction of Cd bioaccumulation in rice

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Biochar 2021年第4期3卷 499-509页

作者： Yuling Liu Haiyan Luo Boqing Tie Danyang Li Shoutao Liu Ming Lei Huihui Du Hunan Engineering&Technology Research Center for Irrigation Water Purification College of Resources and EnvironmentHunan Agricultural UniversityChangsha 410128People’s Republic of China Key Laboratory of Southern Farmland Pollution Prevention and Control Ministry of AgricultureChangsha 410128China Hunan Institute of Agro-Environment and Ecology Changsha 410128China

The application of Fe-Mn-modified biochar for the remediation of Cd-contaminated soil over long time periods has been little studied.In this paper,we describe the performance of coconut-shell-derived biochar modified with ferromanganese in relation to soil Cd stabilization and rice Cd bioaccumulation during a 3-year laboratory study.Different application dosages(0.05-0.5 wt%)and different rice varieties(the early and late rice)are also considered.The results show that ferromanganese is mainly loaded in biochar pores as MnFe_(2)O_(4),and that it decreases the specific surface area(SSA)and total pore volume of biochar.ferromanganese biochar(0.5 wt%)applied to paddy soil is more effective than the same dose of pristine biochar in decreasing the soil-exchangeable Cd fraction(27.42-41.92%vs 22.56-33.85%),predominantly by decreasing soil Eh and increasing root Fe plaques.ferromanganese biochar application helps to reduce Cd bioaccumulation in rice,especially in the grain(up to 48.6%-61.0%),and grain Cd levels(0.2 mg/kg)are all within the acceptable limit for food security in China.It is shown that ferromanganese modification and application can maintain soil at low redox status,keep root Fe plaques at a high level,and may also increase the stability of pristine biochar.All of these effects contribute to maintaining its high remediation efficiency over a 3-year inoculation period.The results presented in this paper demonstrate the potential appli-cations of ferromanganese biochar in soil remediation and the improvement of food safety.

关键词： Biochar ferromanganese Modification Cadmium Stabilization

Control of Oxygen Potential and Its Effect on Dephosphorization of ferromanganese

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Journal of Iron and Steel Research(International) 1999年第1期6卷 8-11页

作者： Dong Yuanchi Guo Shangxing Chen Erbao East China University of Metallurgy

The relation of Lp(the ratio P content in slag to P content in ferromanganese) and L,(the ratio Mn content in slag to Mn content in ferromanganese) with C content[C]in ferromanganese were tested by means of the equilibrium experiments of P and Mn between ferromanganese and BaO-BaF-MnO slag system.The results show that there exists in ferromanganese an optimum C content[C]* corresponding to maximum Land minimum L> which is closely related to oxygen potential in the system and the activity of P in the alloy.The control limits of oxygen potential in dephosphorization of ferromanganese are then analyzed.The theoretical limits and measures to improve ferromanganese dephosphorization with BaO-based slag are studied comprehensively based on previous research.

关键词： ferromanganese dephosphorization oxygen potential activity

STUDY ON MAIN FACTORS OF THE CONTROLLING GEOCHEMICAL CHARACTERISTICS OF ferromanganese NODULES (Ⅱ)——FORMATIVE MECHANISM OF DIFFERENT GEOCHEMICAL TYPE NODULES

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Science China Chemistry 1992年第4期35卷 500-512页

作者：鲍根德 The Second Institute of Oceanography State Oceanic Administration Hangzhou 310012 PRC

Based on the study of geochemical characteristics of the different Mn/Fe ferromanganese nodules, the formative mechanism of different geochemical type ferromanganese nodules are discussed in detail by analysing the relationship between different Mn/Fe nodules and their sediments (rock), pore water, overlying water, biological (bacteria) information from the rare earth element geochemistry, sedimentary geochemistry and biogeochemistry. The result shows that the formation mechanism of different Mn/Fe nodules is obviously different, and according to the formative mechanism, the ferromanganese nodules of the South China Sea and the Northern Central Pacific can be classified principally into three geochemical types: volcanic sedimentary mechanism (Mn/Fe≤1.50), oxidation diagenetic mechanism (Mn/Fe>1.50≤2.50) and suboxic organic diagenetic mechanism (Mn/Fe>2.50).

关键词： ferromanganese nodule geochemistry formative mechanism sediment overlying water pore water bacteria