A SIMPLE EQUATION FOR SINK-FLOAT DATA

The published results of the sink-float data on coals of different ori gins have been analysed for smoothing and interpolation. The cumulativ e weight fraction of material floating and the ash content of the floa t fraction were used to estimate the recoveries of ''non-ash'' and ''a sh'' material at each relative density level. A simple equation was th en derived relating recovery to the relative density. Further, it has been shown that these equations can be used for the purpose of interpo lation thereby reducing the need for carrying out sink-float tests at several relative density levels.