Study on Reduction Mechanism of Iron Oxide by Industrial Lignin

To effectively utilize industrial lignin, a large amount of waste produced by the pulp and paper industry, this paper primarily explores its potential as a substitute for coal-based reducing agents in the reduction of iron oxides. The weight change, phase change, and activation energy change during the reduction of iron oxide by industrial lignin were characterized using detection methods such as TG-DTG-DSC, XRD, and SEM. The results show that the maximum weight loss rate of industrial lignin reducing iron oxide is (4.52%·min⁻¹) > Lu’an anthracite (2.01%·min⁻¹) > Shenmu bituminous coal (1.57%·min⁻¹). The activation energy variation range during the reduction of Fe₂O₃ by industrial lignin, calculated using the Flynn–Wall–Ozawa (FWO) method, is 241.91~463.51 kJ·mol⁻¹, and the activation energy first decreased, then increased, then decreased slightly with the increase of conversion fraction. There is a coupling effect in the reduction of Fe₂O₃ by industrial lignin.