<p>The robust development of China's iron and steel (IS) industry supports the establishment of a new development pattern focused on “dominant domestic cycle and mutually reinforcing domestic and international cycles.” Reducing energy consumption and gas emissions while maintaining industrial scale has become a key focus for sustainable development. Existing literature has primarily focused on decoupling of economic growth and environmental impacts at the macro level, without systematically revealing the relationship between crude steel output and environmental burdens at the production process level. Consequently, the logarithmic mean divisia Index (LMDI) was employed to distinguish the drivers of energy consumption and gas emissions, extending the analysis to the production process level in this study. Subsequently, the decoupling relationship between energy consumption or gas emissions and crude steel output was elucidated, with advanced technologies serving as key quantifiable indicators. Results indicate that comprehensive energy consumption per ton of steel (Δ<i>E</i>_<i>K</i>) is the dominant factor in reducing energy consumption and gas emissions. Further analysis reveals that ironmaking and converters are the core processes for reducing (Δ<i>E</i>_<i>K</i>), contributing 33.29 and 23.47%, respectively. Decoupling results demonstrate that crude steel output and environmental burden are mostly weakly decoupled, with a trend towards improvement driven by advanced technologies and industry structural adjustments.</p> Graphical Abstract <p></p>