The Reflux Flotation Cell (RFC) has been developed as a game-changing technology to improve fine particle flotation, coarse particle flotation and plant capacity. It has been proved successful for coal flotation. This study compared graphite flotation and coal flotation in the RFC under the operation conditions established for optimizing coal flotation with an objective of extending the RFC to mineral flotation. It was interesting to find that graphite flotation in the RFC produced much lower combustible recovery than coal flotation especially at a high gas flux despite the same surface property and feed size of graphite and coal particles tested. Through the modelling of fluid flow, it was found that the lower combustible recovery from graphite flotation was due to the lower sphericity of graphite particles. The flaky graphite particles promoted a greater dynamic drag force and a greater particle settling velocity compared to coal particles with a greater sphericity. This increased the relative velocity between particles and bubbles in the RFC downcomer, unfavourable for bubble-particle attachment in graphite flotation in the RFC. In addition, a higher gas flux environment in the RFC downcomer produced a higher bubble slip velocity, further increasing the relative velocity between particles and bubbles, exacerbating graphite flotation. Furthermore, the extra gas in the inclined channels pushed more graphite particles to the tailing stream given the higher particle settling velocity. This study indicates a direction of how to optimize graphite flotation in the RFC.

回流浮选槽 (RFC) 是一项改变游戏规则的技术，旨在提高细颗粒浮选、粗颗粒浮选和工厂产能。煤浮选已被证明是成功的。本研究在为优化煤浮选而建立的操作条件下，比较了 RFC 中的石墨浮选和煤浮选，目的是将 RFC 扩展到矿物浮选。有趣的是，尽管测试的石墨和煤颗粒的表面性质和进料尺寸相同，但 RFC 中的石墨浮选产生的可燃回收率比煤浮选低得多，特别是在高气体通量下。通过流体流动建模，发现石墨浮选的可燃物回收率较低是由于石墨颗粒的球形度较低。与具有更大球形度的煤颗粒相比，片状石墨颗粒促进了更大的动态阻力和更大的颗粒沉降速度。这增加了RFC降液管中颗粒和气泡之间的相对速度，不利于RFC中石墨浮选的气泡-颗粒附着。此外，RFC降液管内较高的气体通量环境产生了较高的气泡滑移速度，进一步增加了颗粒与气泡之间的相对速度，加剧了石墨的浮选。此外，由于颗粒沉降速度较高，倾斜通道中的额外气体将更多的石墨颗粒推向尾矿流。本研究为RFC中如何优化石墨浮选指明了方向。