Pelletization Using Humic Substance-based Binder

Abstract

ABSTRACTHumic substances exist widely in lignite coal as high molecular weight organic molecules. They can be used as binders in iron ore pelletization mostly in the form of salt, such as sodium humate and amine humate via extraction from lignite coal. It is worth determining if lignite can be used as a binder without extraction. As a composite binder of organic and inorganics, due to the combustion of humic substance, the strength of fired pellets made with humic substance-based binder decreases slightly. To compensate for this defect and make stronger pellets, cheap calcium bentonite was added into humic substance binder. In this study, a fluxed hematite concentrate was pelletized with various types of binders: lignite plus sodium hydroxide, calcium bentonite activated with modified humic acid (MHA), and MHA binder. Good quality pellets were obtained at optimal parameters. The results show that without extraction procedure, lignite plus sodium hydroxide can be directly used as a binder in pelletization of fluxed hematite; that calcium bentonite improves pellet strength when added to MHA; and that humic substance can partly replace calcium bentonite, reducing the dose of calcium bentonite.