. SEM analysis of the particle morp

. SEM analysis of the particle morphologyFig. 1 demonstrates the micro-scale morphologies of paraffin, redmud, and the paraffin/red mud phase change energy storage composite.As shown in Fig. 1(a), the paraffin surface is relatively smooth andcompact and mainly in the form of disc-like shapes. Fig. 1(b) shows therather vague outline without a fixed shape of red mud with differentparticle sizes. There are pores between the particles. Compared with thepores between the particles observed in Fig. 1(b), there are few visiblepores after paraffin impregnation, as seen in Fig. 1(c)–(f), indicatingparaffin is well impregnated into the red mud pores.3.2. Laser particle size analyser analysis of the particle size distributionFig. 2 shows the particle size analysis of the red mud, paraffin andparaffin/red mud phase change composite. As we can observe fromFig. 2(a), the mean particle sizes of the red mud and paraffin are3.949 μm and 300.144 μm, respectively. The particle size range of red