Abstract: To address the issues of low resource utilization and untapped economic potential of heavy-medium middlings, and to implement the principle of “maximizing coal resource extraction,” the Luliangshan Coal Preparation Plant compared microwave heating and liquid nitrogen condensation to determine the optimal pretreatment scheme, and conducted a feasibility study on the crushing, liberation, and re-separation of middlings. Using a combined methodology of pretreatment, crushing, screening, float-and-sink tests, X-ray diffraction (XRD), and scanning electron microscopy (SEM). The results indicate that liquid nitrogen condensation pretreatment is more conducive to density separation in subsequent float-and-sink tests. When middlings with a particle size of > 6 mm are crushed to below 6 mm for re-separation, the plant can increase clean coal production by 7 500 tons per year, while maintaining middling production at 187 800 tons.The average annual profit increase is estimated at 2.5989 million yuan. At this particle size, the dominant density fraction is 1.6～1.8 g/cm³ (yield of 47.24%), while the low-density fraction of < 1.4 g/cm³ reaches a yield of 7.73% with an ash content of 11.95%. The liberation effect between clean coal and reject is significantly superior to the > 13 mm crushing scheme. The designed 6 mm crushing and re-separation process for coking middlings effectively improves resource recovery, offering substantial economic benefits and resource utilization value.