Utilization of modified copper slag activated by Na2SO4 and CaO for unclassified lead/zinc mine tailings based cemented paste backfill

JOURNAL OF ENVIRONMENTAL MANAGEMENT

卷:290

Article

Chen, Qiusong^1,3  Tao, Yunbo¹  Feng, Yan¹  Zhang, Qinli¹  Liu, Yikai² 

[1] Cent South Univ, Sch Resources & Safety Engn, Changsha 410083, Peoples R China

[2] Univ Padua, Dept Geosci, I-35131 Padua, Italy

[3] Min Res Co Ltd, Sinosteel Maanshan Inst, Maanshan 243000, Peoples R China

关键词: Cemented paste backfill;    Tailings;    Copper slag;    Hydration product;    Unconfined compressive strength;    Microstructure;   

DOI  :  10.1016/j.jenvman.2021.112608

来源: Elsevier

【 摘 要 】

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.

【 授权许可】

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