Ash Fluidity and Regulation Mechanism of Iron-Rich Low-Rank Coal in High-Temperature Gasification Process

Abstract

ABSTRACT To realize the high-efficiency utilization of iron-rich coal, it is necessary to conduct research on ash flow characteristics and regulatory mechanisms. The ash flow test was carried out, and we introduced additives such as Huajin red mud (HJ), pipe scale (GDG), diatomite (GZT), and Naomaohu coal (NMH). The results revealed that the elevated Fe2O3 content triggers the formation of metallic iron, leading to poor high-temperature fluidity. NMH and HJ additives have the ability to depolymerize SiO2 and Al2O3 structures. This generates higher contents of anorthite and sodium nepheline. The inclusion of GDG ash promoted the formation of cordierite and forsterite, contributing to improved slag flow. Caution is warranted when using a higher proportion of GDG ash additive, as excessive MgO can combine with Al2O3 to form a high-melting-point spinel mineral. GZT ash leads to an increase in quartz content. During cooling, mullite preferentially precipitates from the liquid phase, further reducing high-temperature fluidity.