Beneficiation of 6-0 mm fine-grain oil shale using vibrating air-dense medium fluidized bed separator

Abstract The throughput of oil shale is gradually increasing because of the high value it provides for different applications. However, during oil shale mining, a large amount of fine-grain (6-0 mm) material is produced. As the 6-0 mm material has higher oil content and better combustion performance, it can be effectively utilized by performing beneficiation through physical sorting to reduce impurities and upgrade the oil shale grade. In this paper, the physical properties of fine-grain (6-0 mm) oil shale were analyzed. The beneficiation of 6-0 mm oil shale using a vibrating air-dense medium fluidized bed was proposed. The effects of the vibration intensity Γ , gas velocity v , and bed height h on the beneficiation efficiency were systematically investigated. The distribution characteristics of the oil content in the upper, middle, and lower layers of the bed under the optimum operating parameters were studied. Under the optimum operating parameters ( v  = 1.46 cm/s, h  = 85 mm, Γ  = 10.87), the oil content in the upper layer material of the bed is uniform and the fluctuation of the oil content is gentle with better stability. The distribution of the oil content in the middle layer is disorderly, the fluctuation range expands further, and the stability is the worst. The oil content distribution in the lower layer material is uniform with a very small range of fluctuation, and the oil content distribution in the bed material is stable. The yields and oil content of the concentrate are 31.34% and 10.68%, while those of tailings are 68.66% and 0.92%, and the separating accuracy (probable error) is 0.125 g/cm 3 . In conclusion, 6-0 mm oil shale can be effectively beneficiated by the vibrating air-dense fluidized bed separator and it can be recycled and utilized efficiently.