Evaluation of High Mean of Maximum Reflectance(MMR) coals for coke making through selective crushing

Abstract Selective fine crushing of high Mean Maximum Reflectance (MMR) Australian coking coals—Sarji, Peak Down, and PLV—was studied to enhance coke quality and reduce wall pressure during coking. Each coal was crushed to varying degrees (-3.15 mm at 80%, 85%, 90%, and 95%) and carbonized in a pilot-scale coke oven. The resulting coke was evaluated for wall pressure, CSR, CRI, porosity, volatile matter, ash content, and power consumption. Results showed that increasing fine coal content, especially in Sarji coal, significantly reduced wall pressure (from 7.25 to 3.89 kPa) and porosity, while improving CSR (from 62.48 to 69.39) and reducing CRI (from 25.62 to 21.83). These benefits were linked to better particle packing, gas permeability, and reduced swelling. Additionally, coke from finer blends exhibited lower volatile matter and ash, enhancing thermal stability. Power consumption remained stable, highlighting process efficiency. Selective fine crushing proves to be an effective method for producing high-quality coke from high MMR coals.