A Study of the properties and microstructure of high-magnesium nickel slag powder used as a cement supplement

This research aims to use high-magnesium nickel slag crushed into a powder as a replacement for cement and to study their properties and microstructure in concrete. The particle diameter of the nickel slag powder was obtained lower than 75 μm after a process of crushing and sieving. The specific areas, absolute dry densities and particle size distribution (PSD) were analysed to obtain the physical properties of the material. The techniques applied to study their chemical and mineralogical composition were the X-Ray Florescence (XRF), the Scanning Electron Micrograph (SEM). The OPC type 1 was used as a reference in comparison to the experimental material of this research. Without a chemical admixture, the compressive strength of concrete after 28 days is fc' 30 MPa and the specific surface area is 4360 cm²/gr. The compressive strength of high-magnesium nickel slag powder is capable of replacing cement by 20% without altering properties of concrete. According to the XRF technique results, the nickel slag contains silica, calcium, magnesia, and alumina. Furthermore, the image of the SEM-EDS illustrated the slag particle to be sharp, irregular, and containing calcium, silicon, alumina, oxygen, and magnesium. This result confirmed that the XRF technique and SEM-EDS were accurate.