Graphitic carbon spheres (GCS) with an average diameter of 1.6 μm were prepared via a hydrothermal carbonization combined catalytic graphitization method using glucose as carbon source and cobalt nitrate as catalyst precursor. The as-prepared GCS were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and Raman spectroscopy. It was found that the optimal weight ratio of Co catalyst for graphitization of amorphous carbonaceous spheres was 2.0 wt%, and the optimal temperature and dwelling time required for graphitization were respectively 1100 °C and 3 h.

Lightweight materials applied in construction field were prepared using waste iron mine tailings (WIMT) as raw materials, the commercial silicate cement (CSC) as cementing agent, NaOH as the alkali activator, and triethanolamine lauryl sulfate (TLS) as foaming agent via foam-gelcasting method. The effects of water/cement (W/C) mass ratio (0.6-1.0), addition of NaOH (0-0.15wt%) and foaming agent (0-0.3vol%) on the porosity, bulk density, and mechanical properties of the iron mine tailing-based lightweight materials were studied. The results showed that the mechanical properties of iron mine tailing-based lightweight materials were improved by adding NaOH, the as-prepared materials had a 7-day compressive strength of 5.18 MPa, porosity of 51.40%, bulk density of 1.73 g/cm3and thermal conductivity of 0.193 W・(m-1K-1) when the W/C ratio was 0.8, the mass ratio of WIMT/CSC/NaOH 1.85:1:0.15, and foaming agent content 0.3vol%.