Research on CO emission factors of typical magnesia production processes

Magnesia production processes generate carbon monoxide （CO） emissions； however， publicly available measured data on CO emission factors for these processes remain scarce， which constrains the accuracy of emission accounting and mitigation assessment in the industry. To address the lack of basic data on CO emissions from typical magnesia production processes， this study selected three representative magnesia-producing enterprises in Anshan， Liaoning Province， China， covering three typical technological routes： the two-stage calcination process （“light burning-briquetting-shaft kiln dead burning”）， the “suspension calcination-dead burning sintering” process， and the electric arc furnace melting process. Under the condition that enterprises were not equipped with online CO monitoring modules， an estimation approach coupling manual measurements with conventional indicators from the Continuous Emission Monitoring System （CEMS） was developed. By establishing characteristic concentration ratios between CO and nitrogen oxides （NOx） or particulate matter （PM）， and combining them with annual CEMS monitoring data， product-level CO emission factors were calculated. The results showed that the CO emission factors for the two-stage calcination process， the suspension calcination–dead burning sintering process， and the electric arc furnace melting process were 5.35， 5.18， and 1.40 kg/t， respectively， among which the emission level of the electric arc furnace melting process was significantly lower than that of sintering-based processes. This study provides enterprise-level measured CO parameters for the magnesia industry， filling the data gap in emission factors for typical technological routes. It also proposes an emission factor estimation method applicable under conditions where online CO monitoring data are unavailable， which can provide methodological support for pollutant emission accounting and emission inventory development in similar data-constrained industries.