In order to achieve the established goal of "carbon peaking and carbon neutrality", the high-energy steel industry has made every effort to promote carbon emission reduction and accelerate the R&D and application of low-carbon cutting-edge technologies. The long-process sintering process is focused on, the details of the flue gas cycle sintering process and oxygen enrichment sintering technology are deeply investigated, and the flue gas circulation and step oxygen enrichment coupling sintering technology are developed. According to the gas characteristics, the O₂ volume fraction of the sintering machine bellow flue gas is reasonably selected, and 1%~2% of step oxygen enrichment is formed in the circulating flue branch, and the medium and high temperature gas flow medium with a high O₂ volume fraction (18%~20%) is supplied to the sintering. This technology focuses on using oxygen enrichment to make up for the shortcomings of insufficient O₂ volume fraction in circulating flue gas, improve the combustion efficiency of fuel in the sintering material layer, and realize the efficient recovery of waste heat of low-quality sintered flue gas, the reduction of solid fuel consumption, sintered minerals, quality improvement and other functional requirements.