Details

Autor(en) / Beteiligte

• Xie, Ruosong
• Ge, Rui
• Li, Zhishuncheng
• Qu, Guangfei
• Zhang, Yingjie
• Xu, Youxiao
• Zeng, Yingda
• Li, Ziying

Titel

Synthesis and influencing factors of high-performance concrete based on copper tailings for efficient solidification of heavy metals

Ist Teil von

• Journal of environmental management, 2023-01, Vol.325, p.116469-116469, Article 116469

Ort / Verlag

Elsevier Ltd

Erscheinungsjahr

2023

Link zum Volltext

Quelle

Elsevier ScienceDirect Journals Complete

Beschreibungen/Notizen

• Copper tailings containing a large amount of heavy metals such as Pb, Cu, As, Mn, and Cr discharged from its mining are a typical bulk solid waste, which is highly hazardous to human and the environment. This research proposed a sustainable and effective method for the environmentally sound utilization of copper tailings solid waste. A high-strength concrete material with copper tailings as the main raw material was successfully prepared, with a 28-day compressive strength of up to 85.35 MPa, the flexural strength reached 12.46 MPa, and the tailings utilization rate of 60%. The mechanical properties and heavy metal stabilization properties of the prepared high-performance concrete were obtained by adding coarse aggregates such as river sand, while changing the sand rate, cementitious material admixture and water-cement ratio. A long-term leaching experiment of the high-strength concrete material with 190 day was carried and proved that the material can be made with low or no risk of heavy metal contamination in copper tailings. Incorporation of copper tailings into the high-performance concrete hydration mainly contains three mechanisms: (i) Pore sealing effect generated by the formation of tailings geopolymer prompted the hardening of the geopolymer layer to form a monolithic package structure; (ii) The active SiO2 material in copper tailings reacts with Ca(OH)2 in the hydration products to produce a strong volcanic ash effect; (iii) the primary hydration of 3CaO·SiO2(C3S) and 3CaO·Al2O3(C3A) in the cement, and the secondary hydration reaction induced by the copper tailings and silica fume. These mechanisms are blended with each other to form a dense microstructure of the slurry, which embodies extremely high mechanical properties on a macroscopic scale, providing a reference role for the bulk utilization of copper tailings. [Display omitted] •Preparation of high-performance concrete from copper tailings.•This work realizes the high strength of concrete and eliminates heavy metal pollution.•The 28-day compressive strength of concrete reaches the best 85.35 MPa.•Concrete's leaching toxicity meets the requirements of class III water quality standard for surface water of China.•Long-term leaching toxicity experiments show that concrete is stable to heavy metal passivation.