Zhan Wenlong

The Interface Characteristics of High-Temperature Melt of CaO-Al 2 O 3 -MgO-SiO 2 System

The interface characteristics were studied, which contained surface tension and interfacial melting of CaO-Al2O3-MgO-SiO2 system in low basicity at high temperature. The CaO-MgO-Al2O3-SiO2 slag system interface model was simulated by Butler equation and Girifalco-Good equation. At the same time, in the CaO-MgO-Al2O3-SiO2 slag, of which the effect of different basicity on the melting behavior and temperature was simulated and calculated. The experimental result indicated that: the surface tension increases with the increase of A12O3 content in the slag system, when the basicity < 2.0. But the effect of the slag system will gradually decrease with the Al2O3 increasing. The increase of the content of magnesium can improve the melting temperature of slag system and decrease the melting range.

Effect of Microwave Irradiation on Improving Coal Grindability

The effect of microwave irradiation on grinding property of coal was studied by using Hardgrove grindability index tester. Superior grindability of coal was obtained to varying extent after microwave irradiation treatment. The variation in microstructure of pulverized coal during microwave irradiation was observed by utilizing scanning electronic microscope (SEM). The results indicated that the different microwave absorbance of minerals and carbon matrix led to cracks on their interface, by which coal particles were further pulverized and therefore the granularity of coal powder was reduced. Due to the different formation process of various coals, bituminite and anthracite are very different in physical and chemical properties. According to the content of coal pulverization, it can found that microwave irradiation has a stronger pulverizing effect on bituminite in comparison to anthracite.

Effect of Microwave Irradiation on Graphitization of Carbon Matrix in Pulverized Coal

In this study, Raman spectroscopy was utilized to investigate the evolution of char structure in pulverized coal (PC) during microwave irradiation. The results indicated that though microwave treatment was carried out at low powers of 132W or 264W, significant variation in char structure was still observed. Char structure turned out to be more irregular firstly under microwave irradiation. However, char structure of superior regularity was obtained with the extension of irradiation time. It can be conclude that short time microwave treatment may facilitate the chemical activity of coal, while long time microwave irradiation on PC may deteriorate its combustion or pyrolysis property.