Journal
JOURNAL OF ENVIRONMENTAL MANAGEMENT
Volume 290, Issue -, Pages -Publisher
ACADEMIC PRESS LTD- ELSEVIER SCIENCE LTD
DOI: 10.1016/j.jenvman.2021.112608
Keywords
Cemented paste backfill; Tailings; Copper slag; Hydration product; Unconfined compressive strength; Microstructure
Categories
Funding
- State Key Laboratory of Safety and Health for Metal Mines [2019-JSKSSYS02]
- Hunan Provincial Natural Science Foundation Project [2020JJ5718]
- National Science Foundations of China [52074351, 52004330]
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The study found that sodium sulfate was more effective in improving mechanical performance, promoting the formation of C-S-H gel and improving pore distribution, but also led to the deposition of chloride compounds, which could affect mechanical properties.
Serious heavy metals pollution was characterized in the lead/zinc mine tailings dam and surrounding soils, as well as copper slag disposal sites. This study investigates the efficacy of modified granulated copper slag (MGCS) as a partial replacement of ordinary Portland cement (OPC) for lead/zinc mine tailings-based cemented paste backfill (CPB) application using Na2SO4 (CSN) and CaO (CSC) as alkali-activated materials. The effect of different scenarios was ascertained by unconfined compressive strength (UCS). Also, the correlated microstructural evolution and mineralogical phase generation were obtained by scanning electron microscopy (SEM), mercury intrusion porosimetry (MIP), and X-ray diffraction (XRD). The main findings proved that CSN was more effective in improving mechanical performance. Na2SO4 was found associated with C-S-H gel formation accompanied by a compact microstructure and better pore distribution with lower porosity. However, deposition of chloride compound was found in the surface layer of CSN samples, which could bring deterioration to the mechanical properties. Results above extend the knowledge of reusing MGCS as supplementary material to CPB, promoting the concept of a circular economy demand for both lead/zinc mine extraction and copper industries.
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