• • Semi-closed submerged arc furnaces (SAFs) exhibit CO emission factors of 7.06 kg/t (Facility A) and 3.66 kg/t (Facility B), significantly higher than closed SAFs, which show 1.41 kg/t (Facility C) and 0.51 kg/t (Facility D) for their pelletizing processes—a ~6-fold difference that mandates furnace-type-specific emission factors for accurate inventory compilation.
• • The study establishes a novel CO-to-NOx concentration ratio method, enabling continuous CO emission estimation from CEMS NOx data, which is critical for real-time monitoring and regulatory compliance in ferroalloy plants.
• • Furnace sealing degree and raw material ratios are the primary drivers of CO emission variability, with semi-closed furnaces suffering from air infiltration and incomplete combustion, leading to higher CO release per tonne of product.
• • The measured emission factors provide essential baseline data for updating national emission inventories and refining pollution reduction strategies, as previous reliance on generic factors led to significant under- or over-estimation of CO emissions in the high-carbon ferrochrome sector.