An approach for upgrading and pre-enrichment of coal-series oil shale

In this work, a centrifugal drum with a double cone angle structure was proposed to enhance the supergravity separation of coal-series oil shale. The influence of feeding speed and motor frequency on the flow membrane formation in the centrifugal drums were studied by simulation. The average thickness of the flow membrane in different centrifugal drums was compared by experimental test. A supergravity separation system was constructed to investigate the effects of different operational factors on the separation efficiency of coal-series oil shale, and to compare the ash removal efficiency of coal-series oil shale with different cone angle structure separation systems. The results indicated that the flow membrane thickness in the double cone angle centrifugal drum was thicker than that in the single cone angle structure. For the double cone angle drum, the thickness of the flow membrane formed on the upper cone was obviously higher than that on the lower cone. Under the same conditions, the oil content of 0.5–0.25 mm, 0.25–0.125 mm and 0.125–0.074 mm coal-series oil shale concentrates increased by 1.31%, 1.79%, and 2.39%, respectively. This study provides a new approach for achieving ash removal and quality improvement of coal-series oil shale.