Kinetic investigation of self-reduction basic oxygen furnace dust briquettes using charcoals from different biomass

Abstract

This work aimed to characterize charcoal, palm oil charcoal, eucalyptus bark charcoal, and basic oxygen furnace dust (BOFD) to produce self-reducing briquettes. It also intended to investigate the briquettes reduction kinetics, as the activation energy, and the controller mechanism. This approach using these biomass charcoal and steelmaking dust residue has not been reported in the literature. The BOFD was characterized by XRD, SEM-EDS, and ICP-OES. It was determined the content of ash, volatile materials, and fixed carbon in the charcoals. The briquettes were made with a stoichiometric percentage of carbon, 25%, and 50% excess of carbon. The reduction was conducted on thermobalance in the temperature range of 700−1100 °C. Isothermals were applied in each 50 °C with 25 min long to apply the kinetic method Forced Stepwise isothermal analysis (FSIA). The results showed that the BOFD is composed of 52.97 wt% total iron as magnetite, wustite and metallic iron. The kinetics analysis showed that the reduction of the self-reducing briquettes took place in two steps: the chemical reaction as controller mechanism at 700−800 °C with apparent activation energy between 62–138.6 kJ mol−1, and diffusion as controller mechanism with activation energies in the range of 333.4 kJ mol−1 and 450 kJ mol−1 at 850−950 °C, showing comparatively with charcoal that the palm oil charcoal and eucalyptus charcoal could be applied in self-briquettes reduction.

Keywords

• Basic oxygen dust furnace
• Biomass
• Self-reducing briquettes
• Kinetic analysis