Centrifugal elutriation concentration

Hydrochloric acid-hydriodic acid elutriant. Prepared by mixing 1 ml of hydriodic acid stock solution with 9 ml of concentrated hydrochloric acid. The precipitate formed by hydrazine is removed by centrifuging the supernatant then is saturated with gaseous hydrogen chloride. The reagent must be prepared every few days because it decomposes easily. 

As in sedimentation, the concentration of the particles in the elutriators affects the results of measurement. Also the velocity in the elutriators tends to be parabolic rather than uniform and thus introduces errors in measurement. Centrifugal force can also be applied like that in the sedimentation to enhance the performance. Different designs, including horizontal elutriators, are available. 

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