Oxygen-enriched　Combustion-flue　Gas　Recirculation　(OEC-FGR)　Technology　is　one　of　the　main　ways　to　solve　the　problem　of　CO2　emission　during　the　cement　production,　which　can　greatly　decrease　CO2　capturing　cost　while　realize　CO2　enrichment.　However,　there　is　a　lack　of　in-depth　study　of　atmosphere　change　on　the　performance　of　cement　clinker.　An　atmospheric　furnace　utilized　in　the　paper　to　calcinate　cement　clinker　and　pure　mineral　[2CaO·SiO2　(C2S),　No.33-0302,　P21/n　(14),　3CaO·SiO2　(C3S),　No.49-0442,　Cm　(8)]　under　air　and　O2/CO2　atmosphere,　and　the　influence　of　atmosphere　on　the　structure,　composition　and　performance　of　cement　clinker　and　pure　mineral　by　the　means　of　X-ray　diffractometer,　Transmission　Electron　Microscope　and　other　testing　methods　were　studied.　And　then,　the　mechanism　of　atmosphere　influence　on　the　performance　of　cement　clinker　was　revealed　through　simulation　calculations　and　a　Ca-SiO2　diffusion　model　was　constructed.　The　results　showed　that　the　diffusion　coefficients　of　Ca　in　hexagonal　system　and　tetragonal　system　SiO2　are　1.53　×　10−8　m2/s　and　1.26　×　10−8　m2/s,　respectively.　The　O2/CO2　atmosphere　is　conducive　to　the　generation　of　hexagonal　system　SiO2,　thereby　speeding　up　the　generation　of　3CaO·SiO2,　which　contributes　to　the　improvement　of　cement　clinker　strength,　so　the　appropriate　proportion　of　O2/CO2　atmosphere　is　conducive　to　the　improvement　of　cement　clinker　performance;　the　best　O2/CO2　ratio　in　the　study　is　0.31/0.69.　Performance　testing,　structural　analysis,　and　simulation　calculations　were　used　in　the　paper　to　reveal　the　mechanism　of　the　influence　of　atmosphere　on　cement　clinker,　providing　a　theoretical　basis　for　the　cement　industry　to　achieve　carbon　emission　reduction.　©　2025