Hydration Kinetics of Composite Cementitious Materials Containing Copper Tailing Powder and Graphene Oxide.

Shuhua Liu,Xinyi Zhao,Qiaoling Li

doi:10.3390/ma11122499

Abstract

The hydration heat evolution curves of composite cementitious materials containing copper tailing powder (CT) and graphene oxide (GO) with different contents are measured and analyzed in this paper. The hydration rate and total hydration heat of the composite cementitious materials decrease with the increase of CT dosage, but improve with the increase of CT fineness and GO dosage. The hydration process of the cementitious systems undergoes three periods, namely nucleation and crystal growth (NG), phase boundary reaction (I), and diffusion (D), which can be simulated well using the Krstulovic–Dabic model. The hydration rates of the three controlling processes of the composite cementitious system decrease with the increase of CT content, but improve slightly with the increase of CT fineness. GO enhances the controlling effect of the NG process of the cementitious systems with or without CT, thus promotes the early hydration as a whole.

Highlights

Copper tailings are waste materials generated during the purification of precious copper from the copper ores, and 128 t copper tailings will be left over per 1 t refined copper [1,2]
Some studies regarding the use of copper tailings as cement substitution have been conducted, and the results show that the pozzolanic activity of copper tailing powder is fairly low and its optimal replacement ratio is 5% without strength and durability reduction; the replacement ratio can reach up to 30–50% in mass concrete with consideration of the temperature control [2,7,8]
Discussion is the simplified name of CT6-30, 2 stands for 0.02% dosage of graphene oxide (GO)

Summary

Introduction

Copper tailings are waste materials generated during the purification of precious copper from the copper ores, and 128 t copper tailings will be left over per 1 t refined copper [1,2]. According to the United States Geological Survey Bureau, two trillion tons of copper tailings were produced worldwide in 2011 [3]. The cumulative copper tailings in China exceeded 3 trillion tons by 2014; only about 8.2% are recycled [3,4,5]. The rest are mainly disposed of in the tailing pond, which results in a lot of adverse effects. The heavy metal elements in copper tailings poison the surrounding soil and water. As copper tailings are definitely solid gravel, the tailing pond is prone to destabilize and collapse in the case of earthquakes and flooding [6]

Methods

Results

Conclusion