The Experts below are selected from a list of 4254 Experts worldwide ranked by ideXlab platform
Jianwei Zhang - One of the best experts on this subject based on the ideXlab platform.
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Study on the Sloshing of Nickel Ore Slurries With Three Different Moisture Contents
Journal of Offshore Mechanics and Arctic Engineering, 2017Co-Authors: Jianwei ZhangAbstract:A combination of the moisture content, dynamic energy produced by the waves and the vessel engines along with the characteristics of the bulk cargo itself may lead the mixture to liquefy. When the liquefaction of the granular bulk cargo occurs, it may behave like a fluid and can cause the vessel to list or even capsize. In this study, based on a computational fluid dynamics (CFD) solver, a numerical model was developed to simulate the sloshing problem for Nickel Ore slurries with three different moisture contents. The volume of fluid (VOF) method is adopted to capture the movement of the fluid interface. To validate the present model, the simulation results were compared with experimental data. The numerical results are in good agreement with the experimental results. Finally, the present model was used to investigate the dynamic behavior of Nickel Ore slurries with different moisture contents combined with non-Newtonian Herschel–Bulkley and Bingham constitutive equations. After taking the grid and time step independence study, the dynamic moment impacted on the cargo hold model boundaries was calculated. The effects of different moisture contents, the excitation amplitude, and the frequency on the sloshing-induced moment and the free surface deformation were discussed extensively. The results confirm that the proposed model can be used to predict the movement of the Nickel Ore slurry and analyze its impact moment on the cargo hold model when it takes a roll motion.
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Parametric studies on Nickel Ore slurry sloshing in a cargo hold by numerical simulations
Ships and Offshore Structures, 2016Co-Authors: Jianwei ZhangAbstract:AbstractActed by waves, swing and vibration of the vessel, the granular bulk cargo which contains certain moisture content may liquefy and behave like a fluid in cargo hold. When the liquefaction of the cargo occurs, it can cause the vessel to list or even capsize. In this study, based on a computational fluid dynamics (CFD) solver and non-Newtonian constitutive equations, a numerical model was developed to study the sloshing of Nickel Ore slurry in a cargo hold. The volume of fluid method was used to capture the movement of the fluid interface. To validate the proposed model, the numerical results were verified by comparison with available experimental data. To fully understand the sloshing behaviour of the Nickel Ore slurry in the hold, the dimensional analysis was accomplished by using the Buckingham π theOrem. Designating the mean sloshing-induced moment amplitude as an indicator, the deduced eight non-dimensional parameters governing the sloshing of the Nickel Ore slurry in the cargo hold were invest...
Benoit Vigier - One of the best experts on this subject based on the ideXlab platform.
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Syntectonic Mobility of Supergene Nickel Ores of New Caledonia (Southwest Pacific). Evidence from Garnierite Veins and Faulted Regolith
Resource Geology, 2008Co-Authors: Dominique Cluzel, Benoit VigierAbstract:International audienceSupergene Nickel deposits of New Caledonia that have been formed in the Neogene by weathering of obducted ultramafic rocks are tightly controlled by fracture development. The relationship of tropical weathering and tectonic structures, faults and tension gashes, have been investigated in order to determine whether fractures have play a passive role only, as previously thought; or alternatively, if brittle tectonics was acting together with alteration. From the observation of time-relationship, textures, and mineralogy of various fracture fills and fault gouges, it may be unambiguously established that active faulting has play a prominent role not only in facilitating drainage and providing room for synkinematic crystallisation of supergene Nickel silicate, but also in mobilising already formed sparse Nickel Ore, giving birth to the very high grade Ore nicknamed "green gold"
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Syntectonic mobility of supergene Nickel Ores of New Caledonia (Southwest Pacific). Evidence from faulted regolith and garnierite veins.
Resource Geology, 2008Co-Authors: Dominique Cluzel, Benoit VigierAbstract:Supergene Nickel deposits of New Caledonia that have been formed in the Neogene by weathering of obducted ultramafic rocks are tightly controlled by fracture development. The relationship of tropical weathering and tectonic structures, faults and tension gashes, have been investigated in order to determine whether fractures have play a passive role only, as previously thought; or alternatively, if brittle tectonics was acting together with alteration. From the observation of time-relationship, textures, and mineralogy of various fracture fills and fault gouges, it may be unambiguously established that active faulting has play a prominent role not only in facilitating drainage and providing room for synkinematic crystallisation of supergene Nickel silicate, but also in mobilising already formed sparse Nickel Ore, giving birth to the very high grade Ore nicknamed "green gold".
Ping Yang - One of the best experts on this subject based on the ideXlab platform.
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Optimization of the international Nickel Ore trade network
Resources Policy, 2021Co-Authors: Xiaojuan Dong, Zhiliang Dong, Ze Wang, Meihui Jiang, Ping YangAbstract:Abstract Optimizing the structure of the international Nickel Ore trade is of great significance for ensuring the supply of Nickel Ore. In this paper, we select data on the international Nickel Ore trade over ten years from 2009 to 2018 and identify major Nickel Ore net exporters and importers. Then, we construct Nickel Ore trade networks from the supply perspective and the demand perspective. Next, we design an improved dynamic programming model. Finally, we obtain the optimal trade network by solving the model based on an iterative algorithm. We find that the trade costs are reduced through the optimization of the Nickel Ore trade network, but the degree of reduction is not uniform. In addition, we find that the overall optimization proportion of the network in 2016–2018 is the lowest, and the Nickel Ore trade network during this period undergoes spontaneous optimization. Some countries in the trade network, such as Japan, need to be compensated for the increased costs after optimization through policy. We obtain the possible direction of trade optimization for importing and exporting countries for each year. The optimization direction of the Nickel Ore trade is then partly applied to real trade. Nickel Ore importing countries should expand the scope of their supply sources, and exporting countries should adjust the allocation structure of their resources as soon as possible. The optimization of international Nickel Ore trade networks can help reduce energy consumption, promote the rational distribution of mineral resources and realize the sustainable development of resources.
Cécile Quantin - One of the best experts on this subject based on the ideXlab platform.
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leaching behaviour of slag and fly ash from laterite Nickel Ore smelting niquelândia brazil
Applied Geochemistry, 2016Co-Authors: Vojtěch Ettler, Ondřej Sebek, Gildas Ratie, Jeremie Garnier, Zdenek Johan, Martin Mihaljevic, Jindřich Kvapil, Cécile QuantinAbstract:Abstract The laterite Nickel (Ni) Ore smelting operation in Niquelândia (Goias state, Brazil) produced large amounts of smelting wastes, stockpiled on dumps (slags) and in settling ponds (fly ash). In this study we present data on the chemistry, mineralogy and pH-dependent leaching behaviours of these two waste materials. Bulk chemical analyses indicated that both wastes contained significant amounts of potentially toxic elements (PTEs), with substantially higher concentrations in the case of the fly ash (up to 2.51 wt% Ni, 1870 mg/kg Cr and 488 mg/kg Co). The mineralogical investigations carried out using X-ray diffraction analysis (XRD), scanning electron microscopy (SEM) and electron microprobe (EPMA) indicated that the slag was mainly composed of silicate glass, olivine and pyroxene. In contrast, the fly ash was composed of Ni-bearing serpentine-like phases (originating from the furnace feed), Ni-bearing glass, olivine, pyroxene and spinel. The pH-dependent leaching behaviour was performed according the EU standard experimental protocol (CEN/TS 14997) in the pH range of 3–12. The leaching was highly pH-dependent for both materials, and the highest releases of PTEs occurred at pH 3. The slag generally exhibited an U-shaped leaching behaviour of the PTEs as a function of pH, and was found to release up to 48.0 mg/kg Ni, 25.6 mg/kg Cr, and 1.42 mg/kg Co. The fly ash was significantly mOre reactive, and exhibited its highest leaching level of PTEs between pH 3 and 7. The maximum observed release corresponded to 5750 mg/kg Ni, 4.35 mg/kg Cr, and 112 mg/kg Co. The leached Ni concentrations after 24 h of leaching in deionized water exceeded the limit for hazardous waste by mOre than 100x according to the EU legislation (40 mg/kg Ni). X-ray Absorption Near Edge Structure (XANES) and Extended X-ray Absorption Fine Structures (EXAFS) spectra indicated that Ni in the fly ash is predominantly bound in a serpentine-like phase, and during the fly ash experimental alteration it was mainly released from the second shell (corresponding to the atomic distances between Ni and Si, Mg, Fe in high-temperature silicates, glass, and partially dissolved serpentine). This study shows that disposal sites for the fly ash can represent a significant source of local pollution, and direct recycling of the fly ash in the smelting technology (as currently adopted at the Barro Alto new smelter and since few years also at the Niquelândia smelter) is the best environment-friendly option for handling of fly ash in the future.
Gildas Ratie - One of the best experts on this subject based on the ideXlab platform.
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leaching behaviour of slag and fly ash from laterite Nickel Ore smelting niquelândia brazil
Applied Geochemistry, 2016Co-Authors: Vojtěch Ettler, Ondřej Sebek, Gildas Ratie, Jeremie Garnier, Zdenek Johan, Martin Mihaljevic, Jindřich Kvapil, Cécile QuantinAbstract:Abstract The laterite Nickel (Ni) Ore smelting operation in Niquelândia (Goias state, Brazil) produced large amounts of smelting wastes, stockpiled on dumps (slags) and in settling ponds (fly ash). In this study we present data on the chemistry, mineralogy and pH-dependent leaching behaviours of these two waste materials. Bulk chemical analyses indicated that both wastes contained significant amounts of potentially toxic elements (PTEs), with substantially higher concentrations in the case of the fly ash (up to 2.51 wt% Ni, 1870 mg/kg Cr and 488 mg/kg Co). The mineralogical investigations carried out using X-ray diffraction analysis (XRD), scanning electron microscopy (SEM) and electron microprobe (EPMA) indicated that the slag was mainly composed of silicate glass, olivine and pyroxene. In contrast, the fly ash was composed of Ni-bearing serpentine-like phases (originating from the furnace feed), Ni-bearing glass, olivine, pyroxene and spinel. The pH-dependent leaching behaviour was performed according the EU standard experimental protocol (CEN/TS 14997) in the pH range of 3–12. The leaching was highly pH-dependent for both materials, and the highest releases of PTEs occurred at pH 3. The slag generally exhibited an U-shaped leaching behaviour of the PTEs as a function of pH, and was found to release up to 48.0 mg/kg Ni, 25.6 mg/kg Cr, and 1.42 mg/kg Co. The fly ash was significantly mOre reactive, and exhibited its highest leaching level of PTEs between pH 3 and 7. The maximum observed release corresponded to 5750 mg/kg Ni, 4.35 mg/kg Cr, and 112 mg/kg Co. The leached Ni concentrations after 24 h of leaching in deionized water exceeded the limit for hazardous waste by mOre than 100x according to the EU legislation (40 mg/kg Ni). X-ray Absorption Near Edge Structure (XANES) and Extended X-ray Absorption Fine Structures (EXAFS) spectra indicated that Ni in the fly ash is predominantly bound in a serpentine-like phase, and during the fly ash experimental alteration it was mainly released from the second shell (corresponding to the atomic distances between Ni and Si, Mg, Fe in high-temperature silicates, glass, and partially dissolved serpentine). This study shows that disposal sites for the fly ash can represent a significant source of local pollution, and direct recycling of the fly ash in the smelting technology (as currently adopted at the Barro Alto new smelter and since few years also at the Niquelândia smelter) is the best environment-friendly option for handling of fly ash in the future.
