Preparation And Heat-treatment Schedules Of Glass-ceramics With Nickel Smelting De-iron Slag

The industry solid waste is generally prepared for higher-value products which conform to the eco-industrial circular economy. In the paper, the raw material comes from Jinchuan Group Ltd. By mixing with composition regular, clarifying and fluxing agents with casting process, secondary nickel slag (SNS) glass-ceramics can be prepared which is a kind of high mechanical properties and good corrosion resistance. The SNS glass-ceramics is not only used in the industry for its corrosion resistance, but also applied to the building materials. The quantitative analysis of SNS glass-ceramics at different heat-treatment conditions is obtained by Ohlberg scattering method, K method and Riteveld full spectrum fitting method. The XRD results show that the nucleation system exerts little influence on the mass fraction of phases in SNS glass-ceramics:augite,61%～63%; anorthite,21%～27%; glass phase,10%～17%. However, the crystallization system has great influence on the percentage of phase composition. When the crystallization temperatures remain at930℃,980℃,1030℃and1080℃, the mass fractions of augite are81.3%,63.6%,27.7%and20%, those of anorthite are0%,26.3%,48.1%and79%, those of glass phase are13.5%,13.7%,24.2%and1%, respectively. The energy diffraction spectrum (EDS) shows that the changes of three phases in SNS glass-ceramics are caused by ion exchange and migration.The mechanical strength, hardness and elasticity modulus values of SNS glass-ceramics are measured. The greatest strength values of SNS glass ceramic is283.3MPa when the glass-matrix nucleated at780℃for20hrs and then underwent a crystal growth heat treatment at980℃for1hr. The hardness H and elasticity modulus E are obtained by nano-indentation method. The hardness values of glass-matrix, augite and anorthite are9.5GPa,11.0GPa～11.5GPa and10.0GPa, respectively. In addition, the greatest value of elasticity modulus is as high as150GPa. The fracture toughness of SNS glass-ceramics is also obtained by nano indentation and Vickers hardness indentation method, which show almost the same results. The fracture toughness of glass-matrix is0.99MPa-m1/2. In the same way, the fracture toughness of two crystals, augite and anorthite, are1.90MPa·m1/2～2.15MPa·m1/2and3.36MPa·m1/2.The relationship of thermal analysis parameters and nucleation-temperature curve is determined. It is found that the change trend of peak height (8T)p temperature is consistant to the nucleation curve. The crystallization activation energies of SNS glass-ceramics are calculated as301.2kJ/mol and279.8kJ/mol by Owaza and Kissinger equation, respectively. The grain sizes distribution curves of SNS glass-ceramics are also obtained by the small X-ray scattering method (SXAS) and the curve obtained at780℃(nucleated for20h) and crystallized at980℃for1h is obvious different from others. The fractal analysis is used and the fractal dimensions of SNS glass-ceramics at different heat-treatment schedules are2.22-2.46.