Large-scale design and testing of an improved fine coal dewatering system
Abstract
Fine coal (-500 μm) is notoriously difficult to dewater. It is not
uncommon for a dewatered product to have a moisture content as
high as 30 per cent after vacuum filtration. This poses several
handling and financial problems to such an extent that a lot of fine
coal is discarded onto slurry waste ponds. A novel way of
dewatering fine coal was developed at North-West University. It
entails deliberately damaging the filter cake during dewatering to
allow for an increased flow of air through the cake at the expense of
the applied pressure differential. This method resulted in an average
improvement in final cake moisture of between 3 per cent and 5 per
cent when executed in the laboratory under controlled conditions. A
device was designed that could be fitted onto existing belt filters
that would damage the filter cake as it passes by. This device was
tested on a vacuum belt filter installation at a coal beneficiation
operation in the Waterberg coal field in South Africa. The results
showed a 3 per cent reduction in final moisture of the cake, proving
the validity of the method at full industrial scale.
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- Faculty of Engineering [1122]