Green coconut husk biochar- a sustainable reductant in ironmaking processes

This study explores the potential of green coconut husk biochar (GCB) as an alternative reductant in ironmaking by evaluating its composition, calorific value, and reduction efficiency in comparison to non-coking coal and coke. Pyrolysis of coconut husk at 500 °C for 45 min produced biochar with 65 % fixed carbon, 28 % volatile matter, and low ash content (5.5 %). The gross calorific value (GCV) peaked at 27.4 MJ/kg. Reduction experiments revealed that GCB exhibited faster initial reduction rates at all tested temperatures than both coke and non-coking coal, attributed to its higher volatile and hydrogen content, which promote reducing gas generation. FTIR analysis confirmed the presence of aliphatic C–H bonds and partially aromatic structures, indicating a balance between reactivity and thermal stability. Given its enhanced reduction performance, GCB shows promise not only as a standalone reductant but also as a blending component with conventional coal to improve early-stage reduction kinetics. These findings support the viability of biowaste-derived GCB in promoting more sustainable and efficient ironmaking processes.