Preparation and properties of biomass char for ironmaking

Raw biomass was carbonized by two different heating patterns to produce biomass char at 400, 500, 600 and 700℃ for 30, 60 and 90 min. The composition, microstructure, and combustibility of the derived biomass char were investigated by scanning electron microscopy (SEM) and thermogravimetric analysis (TG-DTG). The effects of preparing conditions on the biomass char's yield and reactivity for reacting with CO₂ were studied. It is shown that the biomass char has typical duct structure or sheet structure, which is different from coal. The contents of N, S, ash and alkali metals in the biomass char are much lower, but its combustibility is better than coal samples, suitable for using as a reducing agent and a heating agent in ironmaking to partially replace coal and coke. The optimum preparing condition of biomass char for ironmaking is to carbonize raw biomass by a constant temperature heating pattern at 500℃ for 30 min.