Scale Recycling Through Self-Reducing Briquettes to Use in EAF

• Published in: ISIJ International 2017/12/15, Vol.57(12), pp.2081-2090
• Main Authors: Bagatini, Maurício Covcevich, Zymla, Victor, Osório, Eduardo, Vilela, Antonio Cezar Faria
• Format: Article
• Language: English
• Subjects: charcoal; EAF; mill scale; reoxidation; self-reduction
• ISSN: 0915-1559; 1347-5460
• DOI: 10.2355/isijinternational.ISIJINT-2017-242

This work is part of a project which aimed to provide a theoretical and experimental basis for recycling of mill scale from mini-mill plants. The focus of the present study was to evaluate the kinetics and the mechanisms of reduction in self-reducing briquettes composed of scale, charcoal and binders, aiming its use in EAF. Such briquettes were submitted to the following tests: thermogravimetry in micro- and macro-thermobalances with analysis of the generated gas, evaluation of the temperature profile inside the briquette and the metallization degree obtained by tests carried out in muffle furnace at a high heating rate. Previous studies, concerning scale and charcoal taken together with the results of this work indicate that both, the kinetics of scale reduction and the heat transfer limit the overall reaction rate of the briquette. However, the relatively high metallization degree of 76% obtained in the high temperature tests indicates the interest in using such the briquettes for scale recycling in industrial plants. The risk of reoxidation is low due to the protective role of gas evolving from the briquette during self-reduction.