Roles and applications status of binders in powder pelletizing

Binder plays an important role in bridging and agglomeration in the pelletizing of bulk materials, which can improve the sintering performance of pellet.The types of powder pelletizing binders, the bridging and bonding mechanism of each binder, and the pelletizing process of various powder materials such as smelting tailings, blast furnace soot, and mine tailings were focus on describing in the paper.After contacting water, bentonite is quickly dispersed into monomer and filled in the void of iron ore powder, which reduces the porosity of the pellets.Meanwhile, the generated adsorbed water layer can make the pellets cause plastic deformation when under impact and avoid fragmentation, thus improving the strength of the pellets.When cement is mixed with water, hydration reaction and crystallization hardening and consolidation will occur.The surface of particles is wrapped around with a thin layer of sodium silicate film, and the particles are connected by sodium silicate film to improve the strength of pellets after curing.The functional group in the organic binder improve the hydrophilicity of the material surface and enhance the interaction between particles.Bentonite is a common and widely used inorganic binder in pellets.Excessive dosage leads to a decrease in pellet grade and an increase in slag content.Part of bentonite and modification of organic binders can be used to reduce the amount of bentonite.Although organic binders will not reduce the grade of pellets, they are expensive compared to inorganic binders, and the mechanical strength of pellets is low, making it difficult to put into practical production on a large scale.The composite binder combines the advantages of the former two binders, with good comprehensive performance and great application prospects.