In this paper, special attention is paid to the scavenging of refractory elements (Ca, Mg, Fe) by kaolin during combustion of a low rank coal. Combustion experiments were carried out on an electrically-heated drop tube furnace at 1300 degrees C. The raw coal and its blends with kaolin additive (1-10 wt% of coal mass) were respectively burned in simulated air atmosphere. Combustion-generated ashes were collected and analyzed by Computer-Controlled Scanning Electron Microscopy (CCSEM). The data were used to elucidate the scavenging of Na/Ca/Mg/Fe by kaolin and the transformation of inorganic species after kaolin addition. Quantitative X-ray diffraction (XRD) analysis and ash fusion tests were carried out to characterize the amount of amorphous species and the fusion temperatures of bulk ashes after kaolin addition, respectively. Backscattered electron images (BSE) were collected on the raw coal and coal/kaolin mixtures to demonstrate the role of the dispersion state of kaolin in metal scavenging. It is found that apart from Na, the added kaolin can also strongly scavenge the refractory elements (Ca and Mg, except Fe) during low rank coal combustion. The scavenging of Na/Ca/Mg by kaolin promotes the formation of amorphous and molten alumino-silicate particles. The high dispersion of fine kaolin particles in coal is a key factor affecting the scavenging process, which provides sufficient opportunities for the contact and reaction between Ca/Mg species and kaolin. Two possible routes are proposed for the scavenging of Ca/Mg by kaolin. One is that kaolin firstly reacts with sodium vapors, forming melting sodium alumino-silicates that favor the capture of Ca/Mg containing species. Another possible route is that, kaolin directly reacts with active CaO/MgO fumes produced from coal combustion, forming Ca/Mg containing alumino-silicates. Kaolin dosage has significant impacts on the ash fusion temperatures. Which firstly decreased with the increase of kaolin dosage, reaching to the lowest at 4 wt%. Then it sharply increased with the increase of kaolin dosage.