Effects of SiO2 Al2O3-CaO/FeO Low-Temperature Eutectics on Slagging Characteristics of Coal Ash

The effects of low-temperature eutectics (LTEs) in SiO2-Al2O3-CaO/FeO on the slagging characteristics were comprehensively studied in the light of ternary phase diagram of 264 typical coal samples; and two novel criteria for coal ash slagging characteristics were proposed. The results show that LTEs are essentially the cause of inducing coal ash slagging, and their amounts are strong ly related to the slagging characteristics. Moreover, the summarized amount of SiO2 and Al2O3 (A, wt%) as well as that of CaO and FeO (B, wt %) can be considered as important factors regarding the formation of LTEs. In addition, both A and B have a significant linear correlation with the ash slagging index. Furthermore, the values of A and B can be employed to define the slagging level (slight, moderate, serious) with higher accuracy, compared with common criteria (e.g., ash softening temperature, base/acid ratio, SiO2-Al2O3 mass ratio and FeO-CaO mass ratio, etc.).