Assessing the mobility of Zn, Pb and Ni during the weathering of Nkana smelter copper slag, Zambia
Mine slag dumps could be point-sources of possible pollutants to the surrounding water and soils. The purpose of this study was to investigate the leaching behavior of zinc, lead and nickel from Nkana copper slag dump of Kitwe in Zambia. To assess the toxicity and hazardous nature of the slag, Bath...
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Elsevier
2024-12-01
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| author | Jonas Harimana Misozi Makangila Jhonnah Mundike Kakoma Kenneth Maseka |
| author_facet | Jonas Harimana Misozi Makangila Jhonnah Mundike Kakoma Kenneth Maseka |
| author_sort | Jonas Harimana |
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| description | Mine slag dumps could be point-sources of possible pollutants to the surrounding water and soils. The purpose of this study was to investigate the leaching behavior of zinc, lead and nickel from Nkana copper slag dump of Kitwe in Zambia. To assess the toxicity and hazardous nature of the slag, Bath Leaching EN 12,457–2:2002, Toxicity Characteristic Leaching Procedure (TCLP) and Synthetic Precipitation Leaching Procedure (SPLP) were employed. The results from these techniques revealed that the copper slag was inert in the open or natural environment. Sequential extraction analysis was conducted to analyze the fractionation of the zinc, lead and nickel using a seven-step procedure. The sequential extraction analysis showed that the 3 metals were predominantly present in the residual fraction. The risk assessment code (RAC) showed that zinc and lead's mobility could pose an environmental risk categorized as low risk, with RAC values of 1.31 % and 1.50 %, respectively. Nickel's mobility fell within the no-risk category with a RAC of 0.32 %. Additionally, the effect of pH, particle size and contact time on the release of the 3 metals were investigated. The results showed that the highest concentrations of zinc and nickel were observed for longer period of exposure (>33 days), in acidic environments (pH 2.2 and pH 3.0), for particle size distribution (<75 μm). However, lead leaching was not affected by the variation of pH or particle size distribution but mostly by duration of exposure. X-ray diffraction (XRD) analysis revealed that diopside (CaMgSi2O6) and quartz (SiO2) constitute the primary phases within the sample. It is recommended to limit the exposure of slag material to acidic environments and minimize the fragmentation of the slag into finer particles as these conditions would promote increased release of zinc, lead and nickel to the surrounding environment. |
| format | Article |
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| issn | 2468-2276 |
| language | English |
| publishDate | 2024-12-01 |
| publisher | Elsevier |
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| series | Scientific African |
| spelling | doaj-art-8177bcd714b9467f8d7af15afa4fe3812025-08-20T01:57:08ZengElsevierScientific African2468-22762024-12-0126e0242610.1016/j.sciaf.2024.e02426Assessing the mobility of Zn, Pb and Ni during the weathering of Nkana smelter copper slag, ZambiaJonas Harimana0Misozi Makangila1Jhonnah Mundike2Kakoma Kenneth Maseka3Department of Environmental Engineering, School of Mines and Mineral Sciences, The Copperbelt University, Kitwe, Zambia; Corresponding author.Department of Environmental Engineering, School of Mines and Mineral Sciences, The Copperbelt University, Kitwe, ZambiaDepartment of Environmental Engineering, School of Mines and Mineral Sciences, The Copperbelt University, Kitwe, ZambiaSchool of Mathematics and Natural Sciences, The Copperbelt University, Kitwe, ZambiaMine slag dumps could be point-sources of possible pollutants to the surrounding water and soils. The purpose of this study was to investigate the leaching behavior of zinc, lead and nickel from Nkana copper slag dump of Kitwe in Zambia. To assess the toxicity and hazardous nature of the slag, Bath Leaching EN 12,457–2:2002, Toxicity Characteristic Leaching Procedure (TCLP) and Synthetic Precipitation Leaching Procedure (SPLP) were employed. The results from these techniques revealed that the copper slag was inert in the open or natural environment. Sequential extraction analysis was conducted to analyze the fractionation of the zinc, lead and nickel using a seven-step procedure. The sequential extraction analysis showed that the 3 metals were predominantly present in the residual fraction. The risk assessment code (RAC) showed that zinc and lead's mobility could pose an environmental risk categorized as low risk, with RAC values of 1.31 % and 1.50 %, respectively. Nickel's mobility fell within the no-risk category with a RAC of 0.32 %. Additionally, the effect of pH, particle size and contact time on the release of the 3 metals were investigated. The results showed that the highest concentrations of zinc and nickel were observed for longer period of exposure (>33 days), in acidic environments (pH 2.2 and pH 3.0), for particle size distribution (<75 μm). However, lead leaching was not affected by the variation of pH or particle size distribution but mostly by duration of exposure. X-ray diffraction (XRD) analysis revealed that diopside (CaMgSi2O6) and quartz (SiO2) constitute the primary phases within the sample. It is recommended to limit the exposure of slag material to acidic environments and minimize the fragmentation of the slag into finer particles as these conditions would promote increased release of zinc, lead and nickel to the surrounding environment.http://www.sciencedirect.com/science/article/pii/S2468227624003685ConcentrationExposureMobilityRiskToxic metals |
| spellingShingle | Jonas Harimana Misozi Makangila Jhonnah Mundike Kakoma Kenneth Maseka Assessing the mobility of Zn, Pb and Ni during the weathering of Nkana smelter copper slag, Zambia Scientific African Concentration Exposure Mobility Risk Toxic metals |
| title | Assessing the mobility of Zn, Pb and Ni during the weathering of Nkana smelter copper slag, Zambia |
| title_full | Assessing the mobility of Zn, Pb and Ni during the weathering of Nkana smelter copper slag, Zambia |
| title_fullStr | Assessing the mobility of Zn, Pb and Ni during the weathering of Nkana smelter copper slag, Zambia |
| title_full_unstemmed | Assessing the mobility of Zn, Pb and Ni during the weathering of Nkana smelter copper slag, Zambia |
| title_short | Assessing the mobility of Zn, Pb and Ni during the weathering of Nkana smelter copper slag, Zambia |
| title_sort | assessing the mobility of zn pb and ni during the weathering of nkana smelter copper slag zambia |
| topic | Concentration Exposure Mobility Risk Toxic metals |
| url | http://www.sciencedirect.com/science/article/pii/S2468227624003685 |
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