Development of Autoclaved Aerated Concrete from Mechanically Activated Magnesium-Rich Nickel Slag

AbstractNickel slag autoclaved aerated concrete (NS-AAC) was fabricated through a hydrothermal synthesis method by using a novel solid waste, mechanically activated magnesium-rich NS, as the main raw material. The influence of the calcium:silicon (C∶S) ratio on the macroscopic and microscopic performance of NS-AAC was investigated. NS-AAC was analyzed by X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), and scanning electron microscopy (SEM). Results showed that a formulation with 0.65 of C∶S exhibited exceptional compressive and flexural strength, which were 3.5 and 2.1 MPa, respectively. The hydrothermal production of NS-AAC, transformed from C-S-H and Ettringite (AFt) to interfingered and overlapped tobermorite and anhydrite, resulted in exceptional mechanical properties. This work proposes a novel approach for the utilization of NS.