In-situ stabilization/solidification of lead/zinc mine tailings by cemented paste backfill modified with low-carbon bentonite alternative
The improper stockpiling of lead/zinc mine tailings results in significant toxic impurities releasing, which threatens both the surrounding environment and human health. Cemented paste backfill (CPB) is considered an effective in-situ remediation way for managing lead/zinc mine tailings. In this stu...
| Main Authors: | , , , , , |
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| Format: | Article |
| Language: | English |
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Elsevier
2022-03-01
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| Series: | Journal of Materials Research and Technology |
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| Online Access: | http://www.sciencedirect.com/science/article/pii/S2238785422000990 |
| _version_ | 1819176562295046144 |
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| author | Qiusong Chen Kai Luo Yunmin Wang Xiaoshuang Li Qinli Zhang Yikai Liu |
| author_facet | Qiusong Chen Kai Luo Yunmin Wang Xiaoshuang Li Qinli Zhang Yikai Liu |
| author_sort | Qiusong Chen |
| collection | DOAJ |
| description | The improper stockpiling of lead/zinc mine tailings results in significant toxic impurities releasing, which threatens both the surrounding environment and human health. Cemented paste backfill (CPB) is considered an effective in-situ remediation way for managing lead/zinc mine tailings. In this study, the mechanical performance and heavy metal retention of CPB were evaluated by comparing the different binder strategies of ordinary Portland cement (OPC), Ca-bentonite, and Na-bentonite. The engineering properties of the mixtures were verified by uniaxial compressive strength (UCS) tests. The phase composition and internal microstructure were obtained by X-ray diffraction (XRD) and scanning electron microscopy (SEM). Toxicity characteristic leaching procedure (TCLP) was performed to ascertain the effectiveness of heavy metal retention capacity. The results showed that the use of bentonite effectively optimized the UCS at early ages. Despite the deterioration is observed at 28 days, the UCS values are still qualified for the engineering application. With XRD and SEM analysis, a great content of amorphous was quantitatively characterized, highlighting the importance of amorphous content in the regulation of mechanical properties. TCLP results indicate that all the Pb, Cd, and As are predominantly incorporated within the cementitious matrix, whereas the Zn is the only concern in which the leachability decreases with the Ca-bentonite proportion. The leachates met the regulation limits (0.1 mg/L) at the CPB samples with 1.28 wt% of Ca-bentonite. Overall, bentonite could be an attractive alternative for the in-situ remediation of lead/zinc mine tailings to revive the stockpile site and reduce the environmental influence of this solid waste. |
| first_indexed | 2024-12-22T21:12:44Z |
| format | Article |
| id | doaj.art-e0abe65522bb4338a90488171c6abc21 |
| institution | Directory Open Access Journal |
| issn | 2238-7854 |
| language | English |
| last_indexed | 2024-12-22T21:12:44Z |
| publishDate | 2022-03-01 |
| publisher | Elsevier |
| record_format | Article |
| series | Journal of Materials Research and Technology |
| spelling | doaj.art-e0abe65522bb4338a90488171c6abc212022-12-21T18:12:29ZengElsevierJournal of Materials Research and Technology2238-78542022-03-011712001210In-situ stabilization/solidification of lead/zinc mine tailings by cemented paste backfill modified with low-carbon bentonite alternativeQiusong Chen0Kai Luo1Yunmin Wang2Xiaoshuang Li3Qinli Zhang4Yikai Liu5School of Resources and Safety Engineering, Central South University, Changsha, 410083, China; Sinosteel Maanshan General Institute of Mining Research Co., Ltd., Maanshan, 24300, ChinaSchool of Resources and Safety Engineering, Central South University, Changsha, 410083, ChinaSchool of Resources and Safety Engineering, Central South University, Changsha, 410083, China; Sinosteel Maanshan General Institute of Mining Research Co., Ltd., Maanshan, 24300, ChinaSchool of Civil Engineering, Shaoxing University, Shaoxing 312000, ChinaSchool of Resources and Safety Engineering, Central South University, Changsha, 410083, ChinaDepartment of Geosciences, University of Padova, Padova, 35131, Italy; Corresponding author.The improper stockpiling of lead/zinc mine tailings results in significant toxic impurities releasing, which threatens both the surrounding environment and human health. Cemented paste backfill (CPB) is considered an effective in-situ remediation way for managing lead/zinc mine tailings. In this study, the mechanical performance and heavy metal retention of CPB were evaluated by comparing the different binder strategies of ordinary Portland cement (OPC), Ca-bentonite, and Na-bentonite. The engineering properties of the mixtures were verified by uniaxial compressive strength (UCS) tests. The phase composition and internal microstructure were obtained by X-ray diffraction (XRD) and scanning electron microscopy (SEM). Toxicity characteristic leaching procedure (TCLP) was performed to ascertain the effectiveness of heavy metal retention capacity. The results showed that the use of bentonite effectively optimized the UCS at early ages. Despite the deterioration is observed at 28 days, the UCS values are still qualified for the engineering application. With XRD and SEM analysis, a great content of amorphous was quantitatively characterized, highlighting the importance of amorphous content in the regulation of mechanical properties. TCLP results indicate that all the Pb, Cd, and As are predominantly incorporated within the cementitious matrix, whereas the Zn is the only concern in which the leachability decreases with the Ca-bentonite proportion. The leachates met the regulation limits (0.1 mg/L) at the CPB samples with 1.28 wt% of Ca-bentonite. Overall, bentonite could be an attractive alternative for the in-situ remediation of lead/zinc mine tailings to revive the stockpile site and reduce the environmental influence of this solid waste.http://www.sciencedirect.com/science/article/pii/S2238785422000990Lead-zinc mine tailingsCemented paste backfillsLow-carbon cementitious binderSustainabilityStabilization/solidification |
| spellingShingle | Qiusong Chen Kai Luo Yunmin Wang Xiaoshuang Li Qinli Zhang Yikai Liu In-situ stabilization/solidification of lead/zinc mine tailings by cemented paste backfill modified with low-carbon bentonite alternative Journal of Materials Research and Technology Lead-zinc mine tailings Cemented paste backfills Low-carbon cementitious binder Sustainability Stabilization/solidification |
| title | In-situ stabilization/solidification of lead/zinc mine tailings by cemented paste backfill modified with low-carbon bentonite alternative |
| title_full | In-situ stabilization/solidification of lead/zinc mine tailings by cemented paste backfill modified with low-carbon bentonite alternative |
| title_fullStr | In-situ stabilization/solidification of lead/zinc mine tailings by cemented paste backfill modified with low-carbon bentonite alternative |
| title_full_unstemmed | In-situ stabilization/solidification of lead/zinc mine tailings by cemented paste backfill modified with low-carbon bentonite alternative |
| title_short | In-situ stabilization/solidification of lead/zinc mine tailings by cemented paste backfill modified with low-carbon bentonite alternative |
| title_sort | in situ stabilization solidification of lead zinc mine tailings by cemented paste backfill modified with low carbon bentonite alternative |
| topic | Lead-zinc mine tailings Cemented paste backfills Low-carbon cementitious binder Sustainability Stabilization/solidification |
| url | http://www.sciencedirect.com/science/article/pii/S2238785422000990 |
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