Use of forestry waste as an alternative raw material for generating metallurgical coke

Forestry waste (FW) is a significant renewable energy source in China. The substitution of coal blends (BC) with forestry waste to produce metallurgical coke was investigated aiming at expanding alternative resources and reducing CO₂ emissions in ironmaking process. The BC with different ratios of FW were carbonized in a fixed bed reactor, and the physicochemical structure of the coke derived from FW/BC co-carbonization was characterized by Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, solid-state ¹³C nuclear magnetic resonance, optical microscopy, and scanning electron microscopy. The results reveal that the suitable incorporation of FW in BC is 10 wt.%, and the index of coke quality exhibits a good correlation with the optical anisotropy index and the aromaticity of the as-obtained cokes. The partial substitution of BC with FW exhibits potential benefits for colloid formation, owing to the higher hydrogen in FW. However, as the substitution ratio of BC with FW increases, it inhibits coke agglomeration due to more tortuous stacked structures formation during volatile releasing process. Moreover, it was identified that the substitution of higher BC ratios with FW results in the partial replacement of aromatic carbons by oxygenlinked carbons and aliphatic carbons. This substitution leads to a reduction in the aromaticity of the as-obtained coke.