To clarify the K modified effects over activated carbon (AC) supported Mn–Ce oxide catalysts, several Mn–Ce/AC and xK–Mn–Ce/AC mixed oxide catalysts prepared via an impregnation method supported on AC were investigated for low-temperature selective catalytic reduction (SCR) of NO with NH₃ in the simulated sintering flue gas. The Mn–Ce/AC catalyst with a K loading of 8% showed the highest catalytic activity, corresponding to 92.1% NO conversion and 92.5% N₂ selectivity at 225 °C with a space velocity of 12,000 h^–1. Furthermore, the 0.08K–Mn–Ce/AC catalyst exhibited better resistance to SO₂ and H₂O than Mn–Ce/AC, which could convert 72.3% and 74.1% of NO at the presence of 5% SO₂ and H₂O, respectively. After K modification, the relative ratios of Mn⁴⁺/Mnⁿ⁺ as well as Ce³⁺/Ceⁿ⁺ and surface adsorbed oxygen increased. Additionally, the reduction performance of the catalyst was improved obviously, and both acid strength and quantity of acid sites increased significantly after the K species were introduced in Mn–Ce/AC. Especially, the NO adsorption capacity of the catalyst was enhanced, which remarkably promoted the denitration efficiency and SO₂ resistance. The SCR of NO with NH₃ on K–Mn–Ce/AC catalysts followed the L-H mechanism.

During the converter steelmaking process, gas-slag-metal three-phase emulsification is realized by injecting gas to complete metallurgical tasks such as slagging, dephosphorization, decarburization, and heating. As green and intelligent development of the steel industry progresses, converter steelmaking injection technology is also constantly innovating. In this review, the types and applications of top blowing injection elements, bottom blowing injection elements, and injection the medium are reviewed. Three different types of combined blowing processes are compared. At the same time, the advantages and disadvantages of different bottom blowing elements and injection media are respectively discussed. Finally, based on the research and application status of converter injection technology, the development direction of converter steelmaking injection technology is discussed. Accelerating the innovation of converter steelmaking injection technology, especially the improvement and breakthrough of high efficiency, reductions the environmental burden, and long life technology, will play an important role in promoting the transformation and improvement of the steel industry.