Feasibility study on the crushing,liberation,and re-separation of middlings in Luliangshan Coal Preparation Plant
NAN Peng
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 Pre-paration Plant compared microwave heating and liquid nitrogen condensation to determine the optimal pretreat-ment scheme,and conducted a feasibility study on the crushing,liberation,and re-separation of middlings.Us-ing 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 2.598 9 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 liber-ation effect between clean coal and reject is significantly superior to the>13 mm crushing scheme.The de-signed 6 mm crushing and re-separation process for coking middlings effectively improves resource recovery,offering substantial economic benefits and resource utilization value.
Keywords：re-separation of middlingscoking middlingscrushing and liberationfloat-and-sink testX-ray dif-fraction(XRD)analysisliberation effect of clean coal and reject
Publication Date：2025-10-31
Online Publishing Date：2026-03-12(First online date of this platform, not the publication date of the document)
Pages：8( 30-37 )