Developing Iron Ore Pellets Using Novel Binders for H2-Based Direct Reduction

Abstract

The transformation from traditional iron- and steelmaking technologies to green H2-based new technologies will require an improvement in the quality and purity of iron ore burden materials. Iron ore pellets are essential inputs for producing direct reduced iron (DRI), but the conventional binders, used in iron ore pelletizing, introduce gangue oxides to the DRI and consequently increase the slag generation and energy consumption in the steelmaking unit. Partial and/or full replacement of the traditional binders with novel organic binders would significantly contribute to improving the process efficiency, particularly in the next-generation H2-based direct reduction technology. This study illustrates the feasibility of pelletizing magnetite iron ore concentrate using four organic binders: KemPel, Alcotac CS, Alcotac FE16, and CMC, in comparison to bentonite as a reference. The study explores the influence of binder type, binder dosage, and moisture content on the characteristics and properties of the pellets. The efficiency of binders was characterized by the moisture content, drop number test, cold compression strength, and H2 reduction of pellets. For dry pellets, CMS was superior among other binders including bentonite in developing dry strength. After firing, the pellets produced by the partial replacement of bentonite with 0.1 wt.% KemPel demonstrate a performance nearly identical to the reference pellets. While the complete replacement of bentonite with organic binder shows a lower performance of fired pellets compared to the reference, it may still be suitable for use in DR shaft furnaces. The cold-bonded pellets demonstrate a superior reduction rate compared to fired pellets.