A Critical Review on Iron-Bearing Cold-Bonded Agglomerates and Their Disintegration in Ironmaking Shaft Furnaces
摘要
Blast furnaces and direct reduced iron (DRI) shaft furnaces are the primary reactors in modern ironmaking. Fine raw materials, such as iron ore fines, iron ore concentrates, fine fluxes, fine solid fuels, and steel mill fine byproducts, must be agglomerated before being charged into these shaft furnaces from the top. Currently, sintering and pelletizing are the dominant agglomeration technologies for processing fine iron-bearing raw materials. However, both processes require firing at approximately 1300 °C using fossil fuels, resulting in high CO2 emissions, significant energy consumption, environmental concerns, and substantial capital and operating costs. Cold-bonded agglomeration technologies present a promising alternative, potentially mitigating many of these issues. Despite their advantages, a major challenge remains: the tendency of iron-bearing cold-bonded agglomerates to disintegrate within shaft furnaces. Since these furnaces operate as counter-current reactors, the presence of excessive fines can impair burden permeability, reducing productivity, and complicating operations. The poor disintegration resistance of cold-bonded agglomerates has been a major barrier to their widespread adoption in large-scale blast furnaces and DRI shaft furnaces. This review paper examines the applications of iron-bearing cold-bonded agglomerates in shaft furnaces, with a particular focus on their disintegration behavior. Key aspects discussed include impacts, underlying mechanisms, measurement methods, and evaluation techniques of disintegration, aiming to address critical questions surrounding the viability of these agglomerates as sustainable ironmaking feedstocks.
Graphical Abstract