Solid Waste Resources for Green Blasting: Composite Fuel with Coal Slag Biochar for Liquid Oxygen Fracturing

Liquid oxygen (LOX) blasting is a rock-breaking technology known for its low dust, noise, and environmental impact. However, wood pulp paper, the traditional absorbent, often exhibits limited LOX adsorption capacity and energy release performance. Unlike prior studies focusing mainly on macroscopic blasting performance, this work engineers the fuel material itself from industrial and agricultural waste and links its structure and thermal behavior to blasting performance. To address these limitations, this study develops a novel porous composite fuel using coal gasification fines and corncob biochar via a foaming process, aiming to enhance LOX adsorption and promote industrial and agricultural waste utilization. LOX adsorption–desorption, ignition, heating rate, and blast funnel experiments and TG–DSC and TG–FTIR analyses were performed to compare the composite with virgin wood pulp paper. The results indicate that a 7:3 biochar-to-coal gasification fine ratio achieves 75% higher eLOX adsorption (0.531 g·cm− 3) than wood pulp paper. Furthermore, the composite fuel exhibits a lower ignition temperature (207.6°C), 50% higher heating rate (7.3°C·ms− 1), and 1.5-fold increase in blast funnel volume than the wood pulp paper. TG-DSC indicates more sustained and intense oxidation with higher heat release, while TG–FTIR shows staged gas evolution with early CO emissions and later dominant CO2–CO formation. Thus, the proposed composite fuel combines high LOX adsorption, rapid ignition, and strong explosive performance, thereby providing a sustainable, high-performance option for green demolition and rock-breaking operations.