Oil shale separation using a novel combined dry beneficiation process

Significant mineral impurities are produced during oil shale mining. However, inorganic minerals can be partially discarded, with an improvement in oil shale quality, through physical separation methods. Based on analysis of physical properties of oil shale, this paper firstly proposes a separation process combining compound dry cleaning and vibrated air dense medium fluidized bed (VADMFB) separation, for separation of oil shale across the full size range of 100-0 mm. We systematically analyzed the effects of changes in vibration amplitude and frequency on separation results and oil ratios for both systems. When oil shale with a size range of 100-6 mm was separated using compound dry cleaning, using optimal vibrational parameters of f = 53 Hz and A = 3.6 mm, yields of concentrate was 20.49%, respectively, with corresponding oil content of 11.20%, The probable error (E) was 0.155-0.21 with the largest oil content segregation degree. Oil shale with a size fraction of 6-0 mm was separated in a VADMFB separator at optimal vibrational conditions (f = 36 Hz and A = 2.5 mm). Resultant yields of concentrate was 21.70%, respectively, with corresponding oil content of 10.1%. E was 0.16-0.185 with the largest oil ratio segregation intensity. This study thus confirms that the proposed combined dry beneficiation process can effectively separate oil shale along the full size range of 100-0 mm.