Project ForgeIn the elutriation leg of a commercial crystallizer containing a mixture of coarse and very fine crystals of the same material, a liquid is pumped vertically upward. The liquid velocity is adjusted such that it is slightly lower than the terminal velocity of the coarse crystals only. Hence
- Athe very fine and coarse crystals will both be carried upward by the liquid
- Bthe very fine and coarse crystals will both settle at the bottom of the tube
- the very fine crystals will be carried upward and the coarse crystals will settle
- Dthe coarse crystals will be carried upward and the very fine crystals will settle
Explanation
Coarse crystals have a higher terminal settling velocity than fine crystals of the same material. If the liquid's upward velocity is set just BELOW the coarse crystals' (higher) terminal velocity, it is still ABOVE the fine crystals' (lower) terminal velocity — so fine crystals get carried upward (elutriated) while coarse crystals settle against the upward flow.
Source: GATE CH 2013 (2013)
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