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Using Natural Radionuclides to Trace Sources of Suspended Particles in the Lower Reaches of the Yellow River

Journal of Ocean University of China 2024年第1期23卷 99-108页

作者： ZHANG Han BURNETT CWilliam ZHANG Xiaojie ZHAO Shibin YANG Disong NAN Haiming YU Zhigang XU Bochao Frontiers Science Center for Deep Ocean Multispheres and Earth System and Key Laboratory of Marine Chemistry Theory and TechnologyMinistry of EducationOcean University of ChinaQingdao 266100China Laboratory for Marine Ecology and Environmental Science Qingdao National Laboratory for Marine Science and TechnologyQingdao 266071China College of Chemistry and Chemical Engineering Ocean University of ChinaQingdao 266100China Department of Earth Ocean and Atmospheric ScienceFlorida State UniversityTallahasseeFL 32306USA North China Sea Environmental Monitoring Center State Oceanic AdministrationKey Laboratory of Ecological Prewarning and Protection of Bohai SeaMNRQingdao 266033China Shandong Provincial Key Laboratory of Marine Ecological Environment and Disaster Prevention and Mitigation Qingdao 266033China

Natural radionuclides are powerful tools for understanding the sources and fate of suspended particulate matter(SPM).Particulate matter with different particle sizes behaves differently with respect to adsorption and desorption.We analyzed the activi-ties and distribution characteristics of multiple natural radionuclides(238U,226Ra,40K,228Ra,7Be and 210Pbex)on size-fractionated SPM at the Lijin Hydrographic Station(Huanghe or Yellow River)every month over a one-year period.Results showed that medium silt(16–32µm)was the main component.As expected,the activity of each radionuclide decreased with an increase of particle size.We examined the sources of SPM with different particle sizes using activity ratios of 226Ra/238U,228Ra/226Ra,40K/238U and 7Be/210Pbex,and concluded that SPM with different particle sizes originated from different sources.Our results indicate that fine SPM(32µm)was mainly derived from resuspension of riverbed sediment.During high runoff periods,the concentration of SPM increased significantly,and the pro-portion of fine particles originating upstream increased.Naturally occurring radioactive isotopes,especially on size-fractionated par-ticles,are therefore seen as useful tracers to understand the sources and behaviors of riverine particles transported from land to sea.

关键词： the Yellow River suspended particulate matter size-fractions radionuclides sediment sources water elutriator

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A Critical Evaluation of Optimizing the Potential for Ore Recovery from Mine Waste Using Multi-Elemental, Geochemical and Petrographic Analysis (MEGPA)

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Journal of Minerals and Materials Characterization and Engineering 2021年第3期9卷 301-315页

作者： Tamba Komba Geology Department Fourah Bay College University of Sierra Leone Freetown Sierra Leone

The growing world demand for metals necessitates the economic extraction of metals from ores of lesser grades and scheduled waste with potential for metal recovery. In which case, efficient skilled-beneficiation is required to achieve such demand. This research paper examines the potential of ore recovery from magmatic Ni-Cu-PGE waste rock in an open pit mine operation. The waste material contains a marginal cut-off grade between the ore and what has been scheduled to be produced as waste throughout its life of mine (LOM). The waste material has the potential for metal recovery to extend the LOM. The main aim was to investigate the appropriateness of the potential for metal recovery using the already generated waste as a baseline model for subsequent waste production. To achieve this aim, the primary objective was to use Multi-elemental, Geochemical and Petrographic Analysis (MEGPA) on carefully selected waste rock samples. While the specific objectives were to examine the liberation of metals and establish optimal cut-off grade based on suitable size fractions for ore recovery. Multi-elemental, geochemical and Petrographic Analysis were carried out on selected size fractions using various instruments such as Scanning Electron Microscope Energy Disperse X-ray (SEM-EDX), X-Ray Diffraction (XRD) and X-Ray Fluorescence (XRF), reflected and transmitted microscopes. Categorization of results shown the predominant bulk mineral abundance to be tremolite, a member of the amphibole group of silicate minerals with composition Ca2Si8O22·(OH)2. Moreover, the result revealed that the economic Ni and Cu sulphides are hosted in pentlandite and chalcopyrite within the waste samples. Liberation of mineral and recovery of metal are in the finer fractions size below 1.5 mm, and that optimum metal recovery is at ≤1 mm. It was concluded from the study that, there is potential for metal recovery from mines waste in finer fractions below 1.5 mm without posing significant metalliferous acid mi

关键词： Magmatic Ni-Cu-PGE AMD size-fractions PS Fragmentation

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