<p>The cement sector significantly contributes to industrial CO₂ emissions, and reducing the carbon emissions of the cement industry has become an urgent problem. Oxy-fuel combustion stands out as the greatest prospective technology in the carbon capture and storage field, with immense potential for achieving carbon reduction objectives. This study employs computational fluid dynamics (CFD) methods to investigate the characteristics of pulverized coal combustion and raw meal decomposition in a cement precalciner. Considering the influence of varying kinetic parameters of CaCO₃ on a precalciner, the flow and temperature field distributions, species distributions, raw meal decomposition rate, and NO_<i>x</i> generation under 21% O₂/79% N₂ and 21% O₂/79% CO₂ atmospheres were analyzed in detail. Results show that changing the combustion atmosphere from 21% O₂/79% N₂ to 21% O₂/79% CO₂ has no obvious effect on the flow field. However, the maximum temperature decreases; the NO_<i>x</i> emissions are reduced by 19%, and the high concentration of CO₂ in the flue gas simplifies the carbon capture process, helping to reduce energy consumption in the decarbonization of the cement industry. In addition, high CO₂ partial pressure reduced the decomposition rate of raw meal from 96.6% to 82.3%, and increased the outlet temperature by 118 K. Therefore, the pollutant emissions and carbon capture costs in the cement industry can be effectively reduced under the O₂/CO₂ atmosphere.</p>