DESIGN, FABRICATION, AND PERFORMANCE EVALUATION OF A LOW-COST OPEN-AIR FURNACE FOR ALUMINIUM AND PLASTIC RECYCLING APPLICATIONS

This study presents the design, fabrication, and experimental evaluation of a low-cost open-air furnace for melting aluminium and common thermoplastics, targeting small-scale recycling and artisanal foundry processes. Built from locally sourced materials including mild steel, refractory lining, ceramic wool insulation, and a graphite crucible, the furnace incorporates a blower-driven tuyere to support combustion. Melting performance was assessed across varying batch sizes (0.5–2.0 kg), measuring melting time, fuel consumption, peak temperature, and thermal efficiency. Results showed near-linear scaling of melting time and fuel use with batch mass. Aluminium melting averaged 27.7 to 98 minutes with 6.7–7.0% thermal efficiency, while plastic (HDPE) melted in 11 to 41 minutes with slightly lower efficiency (~6%). The furnace demonstrated consistent thermal performance with repeatable operation. Low efficiency was attributed to substantial heat losses through radiation, convection, and exhaust gases. Recommendations include enhanced refractory insulation, improved combustion air control, and heat recovery integration to reduce fuel consumption and emissions. Despite limitations, the furnace offers a practical, affordable technology for decentralized recycling in low-resource settings.