• • The two-stage calcination process (light burning-briquetting-shaft kiln dead burning) exhibits a CO emission factor of 5.35 kg/t, establishing a benchmark for fuel-intensive sintering routes; this value is critical for accurate national emission inventories and mitigation target setting in the magnesia sector.
• • The suspension calcination–dead burning sintering process yields a CO emission factor of 5.18 kg/t, marginally lower than the two-stage route, indicating that process design variations within sintering technologies have limited impact on CO intensity, thus requiring process-level controls rather than simple technology switching.
• • The electric arc furnace melting process demonstrates a significantly lower CO emission factor of 1.40 kg/t, representing a 74% reduction compared to the two-stage calcination process; this quantifies the environmental advantage of electrified production and supports policy incentives for electric arc furnace adoption.
• • The study introduces a novel estimation method coupling manual CO measurements with CEMS data for NOx and PM, enabling CO emission factor derivation in the absence of online CO monitors; this methodological innovation is transferable to other industries with similar monitoring constraints, enhancing emission accounting accuracy.