Some newer insights had been reported in this paper on synthesis and application of calcium aluminate coated graphite in alumina–carbon refractory castables. The course of evolution of AlO4 (tetrahedral) and AlO6 (octahedral) units in the nanocoating was investigated by XRD (X-ray diffraction), Raman spectroscopy and FTIR (Fourier transformed infrared spectroscopy) studies. An extended research on the resemblance and disparity between sol–gel and conventional refractory cements were also explored. FESEM (Field Emission Scanning Electron Microscopy), XRD of coated and uncoated graphites had been revisited with a special study on ESEM (environmental scanning electron microscopy) of those two. The hydrophilic thin film containing Ca-doped γ-Al2O3 phases rendered a decisive influence on graphite retention in castable matrix. A comparison between pore size distribution and thermogravimetric analysis (TGA) of two fired castable refractories advocated the superiority of the one containing coated graphite. Determination of corrosion and penetration indices by the static slag corrosion test, supplemented with microstructural studies, confirmed that the less porous castable containing coated graphites excelled again in the harsh environment. © 2015 Elsevier Ltd and Techna Group S.r.l.