Reaction Kinetics of Palm Char and Coke with Iron Oxides in EAF Steelmaking Slag

Abstract

The reaction kinetics, activation energy, and reduction rates of different carbon reductant properties with electric arc furnace (EAF) slag determine the effectiveness of carbon in EAF steelmaking. This article investigates the interaction between slag and carbonaceous materials derived from palm char and coke. Palm shells were converted into palm char using chemical activation method (phosphorus acid, H3PO4) and pyrolyzed at 450 °C for 2 h in a horizontal tube furnace. Then, all the carbonaceous materials were mixed with iron oxide from slag with mass ratio of 1:3.73. The reduction reaction was carried out in a horizontal tube furnace at different temperature ranges of 1250–1550 °C under argon gas to understand the reaction kinetics, activation energies, and reduction rates of iron oxide from EAF slag with palm char and coke. All iron oxides in EAF slag were completely reduced into metallic iron at 1550 °C for both reductants. The phase and quantity of reduced iron were confirmed by Rietveld refinement method using X-ray diffraction (XRD) pattern and energy-dispersive X-ray spectroscopy (EDX). Palm char/slag has lower activation energy value, E (38.52 kJ/mol), than coke/slag (47.75 kJ/mol). The reaction rate of palm char was found faster (4.99 × 10–5 mol/cm2 s) than coke due to larger specific surface area, higher pore volume, amorphous carbon structure, and higher fixed carbon with high volatile content leading to lower activation energy, thus accelerating the iron oxide reduction rates. This finding forms the basic understanding of the reaction between EAF slag and carbonaceous materials for future research on the production of palm char as a feasible carbon reductant in EAF steelmaking.