Paraffin/red mud phase change energy storage composite incorporated gypsum-based and cement-based materials: Microstructures, thermal and mechanical properties.

In this study, paraffin/red mud phase change energy storage composites were fabricated at 4 mix proportions with paraffin to red mud ratios of 0.4:0.6, 0.45:0.55, 0.5:0.5, and 0.55:0.45 by a mixed mill-heating method. Scanning electron microscopy (SEM) and Fourier transform infrared (FT-IR) results reveal that paraffin flows well into red mud pores and has good compatibility. The differential scanning calorimetry (DSC) results reveal that the melting temperatures of the paraffin/red mud phase change energy storage composite vary from 75℃ to 85℃, and the latent heat value is approximately 25-40J/g. High thermal stability is observed by the thermogravimetric analysis (TG) method. The Brunauer Emmett Teller (BET) isotherms, laser particle sizer, X-ray diffraction analysis (XRD), and laser Raman spectrograph (LRS) show that the phase change energy storage composite does not produce a new material from the raw materials and that the material has a stable performance. Furthermore, the paraffin/red mud phase change energy storage composite was incorporated into the cement-based and gypsum-based materials at 10%, 20%, and 30% weight. The heat storage performance can be improved remarkably with an increase in the addition of phase change energy storage composite replacement. The compressive strength change is minimal with the addition of 10% and 20%, and the compressive strength decreases by nearly 40% with the addition of 30%. The paraffin/red mud phase change energy storage composite has a large influence on the flexural strength.