Experiments and Modeling of Ash Mineral Evolution in Burning High-Sulfur Coal with Lime

摘要

The mineral phase evolution of ash was studied when high-sulfur coal was burnt with CaO at different proportions. Experiments were carried out in a drop-tube furnace. Modeling via FACTSAGE was performed by obtaining the absent thermochemical property data of the key mineral 3CaO-3Al2CV CaSO4 and expanding the database. It was found that the ash mineral phases follow a certain rule to evolve and have an immense potential for modification. At low CaO proportion, 2CaO·Al2O3·vSiO2 might be the dominant mineral phase in ash. However, with the increase of CaO addition, the amount of 2CaO·Al2O3· SiO2 may decrease and the amount of 2CaO·SiO2 and 3CaO·3AlO3·CaSO4 may increase noticeably. Owing to the excellent hydraulic characteristics of the latter two minerals, coal ash is very possible to become cement-like. The findings may open up an efficient way to burn the high-sulfur coal. The burning of high-sulfur coal with lime may result in an attractive sulfur fixation as well as a high-quality byproduct.