Low- and ultra-low-carbon carbon-containing refractories: Development, challenges, and prospects

Over the past two decades, low-carbon carbon-containing refractories (LCCRs), particularly low-carbon MgO–C bricks, have undergone significant development and seen increasing application in clean-steel production, providing a more sustainable alternative to high-carbon MgO–C and magnesia–chrome refractories. The key challenge has been to maintain thermal-shock resistance, oxidation resistance, and corrosion performance despite the substantial reduction in carbon content. This review traces the evolution of LCCRs, beginning with the motivations and design principles underlying their development. Advances in aggregate engineering—including phase-transformation toughening, thermal-expansion mismatch design, and the use of microporous or coated aggregates—have restored toughness and spalling resistance even at carbon levels below 5 wt%. Carbon sources and binders have been redesigned not only to fill residual porosity but also to serve as precursors for in-situ secondary bonding phases, while catalytically modified binders produce nanocarbon networks that strengthen interfacial bonding. Multifunctional antioxidants, combined with atmosphere and porosity control, stabilise microstructures, suppress carbon loss, improve mechanical strength, and enhance corrosion resistance. Micro-/nano-reinforcements, surface coatings, and densification technologies have been employed to construct hierarchical architectures that further improve strength, thermal-shock resistance, and slag corrosion resistance. Extensive industrial trials have confirmed that these innovations can equal or exceed the campaign life of conventional refractories while reducing heat loss, minimising carbon pick-up, and improving steel cleanliness. The review concludes with a discussion of future prospects and remaining scientific challenges, offering guidance for the rational design of next-generation LCCRs.