Effect of bubbles addition on teetered bed separation

To improve the separation efficiency of a conventional Teetered Bed Separator (TBS) in beneficiation of fine coal with a wide size range, an Aeration TBS (A-TBS) was proposed in this investigation. The bubbles were introduced to A-TBS by a self-priming micro-bubble generator. This study theoretically analyzed the effect of bubbles on the difference in hindered settling terminal velocity between different density particles, investigated the impact of superficial water velocity (VSW) and superficial gas velocity (VSG) on bed fluidization, and compared the performance of the TBS and A-TBS in treating 1-0.25 mm size fraction particles. The results show that the expansion degree of fluidized bed which was formed by different size particles or has different initial height, is increased by the introduction of bubbles. Compared with the TBS, at the same level of clean coal ash content, the A-TBS shows an increase in the combustible recovery of clean coal, ash content of tailings, and practical separation density by 5.26%, 6.56%, and 0.088 g/cm(3) respectively, while it shows a decrease in the probable error (Ep) and VSW by 0.031 and 3.51 mm/s, respectively. The addition of bubbles at a proper amount not only improves the separation performance of TBS, but also reduces the upward water velocity. (C) 2015 Published by Elsevier B.V. on behalf of China University of Mining & Technology.