a series of launders 40 a series of de aeration devices 50 and a reservoir 60 the housing 20 is used to house the plate arrays 30 launders 40 de aeration devices 50 and reservoir 60 it should be appreciated that the housing 20 may be shaped and sized differently according to design requirements it should also be appreciated that a top of the housing 20 is not shown in the figs in order to more clearly shown the plate arrays 30 and launders 40 there are six sets of plate arrays 30 however it should be appreciated that the number plate arrays 30 may be varied depending on design criteria each plate array 30 is made up of a set of spaced apart parallel inclined plates 31 for clarity only a minimal number of plates 31 have been illustrated within each plate array 30 it should be appreciated that the number of plates 31 the size of the plates 31 the angle of inclination of the plates 31 and the spacing of the plates 31 can again be varied according to design criteria longitudinal members 32 are located on sides of respective sets of plates 30 three launders 40 are used to catch the particles located with coal slurry after the coal slurry has passed through the plate arrays 30 launders 40 are spaced between respective.