Baseline Testing of a Filter Press and Solid-Bowl Centrifuge for Dewatering Coal Thickener Underflow Slurry

Abstract

Laboratory testing was conducted to evaluate the performance of a plate-and-frame filter press and solid-bowl centrifuge for dewatering a bituminous coal refuse slurry. Filter press testing was conducted using a pilot-scale Technicas Hidraulicas (TH) filter press, which contains a single set of plates. The unit is also equipped with an air-blow system to remove additional moisture from the filter cake voids. Testing was conducted to evaluate the effects of filter time on filtrate flow and solids content, cake moisture, solids recovery, and unit capacity. Product moistures ranged from 27.3% to 29.6%. Filtrate solids contents were less than 0.6% with solids recoveries over 98%. The unit capacities ranged from 73 kg/hr/m2 to 131 kg/hr/m2, with the lower values corresponding to the lower cake moistures. Centrifuge testing was conducted using a Sharples P660 solid-bowl centrifuge. Testing was conducted at several slurry feed rates at one dam setting with another test at a second dam setting. Product moistures ranged from 24.2% to 36.4%. Centrate solids ranged from 0.5% to 11.0% with solids recoveries from 65.2% to 98.4%. The solids feed rates ranged from 89 kg/hr to 338 kg/hr. Lower product moistures were associated with higher solids feed rates but at lower solids recoveries.