Froth flotation and subsequent dewatering circuit optimization

The proper selection of dewatering equipment downstream of flotation is vital in maximizing preparation plant yield. As such, mismatched flotation and dewatering equipment can lead to catastrophic reductions in plant profitability. This paper covers optimum flotation and subsequent dewatering circuit configurations for thermal and coking coal worldwide. The benefits of using deslime column flotation together with screen bowl centrifuges for thermal coals will be discussed, with numerous successful applications mentioned. Likewise for coking coals, conventional versus column flotation applications will be reviewed. The benefits of the Australian practices of dewatering "by-zero" froth concentrates using disc or horizontal belt vacuum filters will also be quantified. The advantages of using pressure filtration in the USA and Canada compared to using centrifuges on by-zero froth concentrates will be discussed in detail, with industrial examples. In particular, the frothing problems seen in many plants using centrifuges to dewater conventional by-zero froth, and more particularly column froth concentrates, will be highlighted. The paper will conclude with a section describing successful applications of slimes flotation followed by pressure filtration.