Experimental study on air dry separation and quality improvement of oil shale fines

Addressing the challenge of limited wet quality improvement of oil shale end ore (<13 mm) in the arid and water-scarce environment of Xinjiang, this study employs composite dry sorting technology and systematically investigates the effects of mineral properties and process parameters on sorting efficiency. The findings indicate that the ash content of the raw ore reaches 82.70%, with fine-grained material (≤0.5 mm) comprising over 60%. Additionally, the yield of low-density minerals (<2.35 g/cm3) is only 29.58%. A significant negative correlation exists between the density of oil shale and tar yield, with a density threshold of <2.35 g/cm3 corresponding to a tar yield of 8.35%. Through one-factor and optimization tests, optimal process parameters were established as 60% valve opening, 40 Hz vibration frequency, and a 70° eccentric block clamping angle. Under these conditions, the refined mineral yield achieved 61.98%, and the recovery of target minerals reached 93.27%. This study validates the feasibility and high efficiency of wind dry separation technology for upgrading oil shale end minerals, providing technical support for the clean utilization of oil shale resources in arid regions.